Feed Check Valve 14364i
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CONTENTS
CONTENTS Introduction Check valve definition Industrial application Types of valve and its application Selection of check valve Feed check valve Application Design and analysis explanation Introduction about pro-E and analysis Finite element analysis Photography Conclusion Reference
INTRODUCTION
INTRODUCTION In fast moving world the time is very important criteria. But in the manual program time takes more and more for every work in the world In the production department drawing is very important for design the various parts. In the manual work, its takes more time and is also very difficult to draw various components compare to CAD. So, to avoid these difficulties, CAD implements for quick & accurate design. Computer aided design have various packages are Auto CAD, Pro-E, etc. Auto CAD is using for 2D drawing and Pro-E is the latest implement in CAD, Which is especially using for 3D modeling. Most of the industry Pro-E is using for creating a new Design and modification of existing Design. Before to start the production we can visualize entire parts and assembly view of the model by using Pro-E. We were design the entire part of FEED CHECK VALVE and assembled it. Ansys software is used for analyzing the 3d modeling objects. The ANSYS program has much finite element analysis, capabilities, ranging from a simple, linear, static analysis to a complex non–linear, transient dynamic analysis.
CHECK VALVE
CHECK VALVE Check valves are mechanical valves that permit gases and liquids to flow in only one direction, preventing process flow from reversing. They are classified as one-way directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the valve closed. The mechanics of check valve operation are not complicated. Check (non-return) valves are installed in pipelines to allow flow in one direction only; helping to protect equipment and processes. The operation, benefits, applications and selection of different designs, including lift, disc, swing and wafer check valves are explained in this tutorial.
The printable version of this page has now been replaced by The Steam and Condensate Loop Book
View the complete collection of Steam Engineering Tutorials
Check valves, or non-return valves, are installed in pipeline systems to allow flow in one direction only. They are operated entirely by reaction to the line fluid and therefore do not require any external actuation. In this text, the expected, or desired direction of flow is termed 'forward flow', flow in the opposite direction is 'reverse
flow'.
INDUSTRIAL APPLICATION
INDUSTRIAL APPLICATION Pump The check valves on this steam locomotive are located under the small dome between the chimney and the main dome. check valves are often used with some types of pumps. Piston-driven and diaphragm pumps such as metering pumps and pumps for chromatography commonly use inlet and outlet ball check valves. These valves often look like small cylinders attached to the pump head on the inlet and outlet lines. Many similar pump-like mechanisms for moving volumes of fluids around use check valves such as ball check valves. The feed pumps or injectors which supply water to steam boilers are fitted with check valves to prevent backflow.
Industrial processes Check valves are used in many fluid systems such as those in chemical and power plants, and in many other industrial processes. Check valves are also often used when multiple gases are mixed into one gas stream. A check valve is installed on each of the individual gas streams to prevent mixing of the gases in the original source. For example, if a fuel and an oxidizer are to be mixed, then check valves will normally be used on both the fuel and oxidizer sources to ensure that the original gas cylinders remain pure and therefore nonflammable.
Domestic use Some types of irrigation sprinklers and drip irrigation emitters have small check valves built into them to keep the lines from draining when the system is
shut off. Also used with most home made snowmakers. Check valves used in domestic heating systems to prevent vertical convection, especially in combination with solar thermal installations, also are called gravity brake. Rainwater harvesting systems that are plumbed into the main water supply of a utility provider may be required to have one or more check values fitted to prevent contamination of the primary supply by rainwater.
The application of mathematics to the operation of check valves is of relatively recent origin. Pool, Porwit, and Carlton40 describe a calculation method for check valves with a hinged disc that involves setting up the equation of motion for the disc and applying to that the deceleration characteristic of the flowing fluid within the system. Before the equation of motion for the disc can be written, certain physical constants of the valve must be known. The calculation determines the reverse flow velocity at the instant of sudden shut-off.
TYPES OF VALVE AND APPLICATION
TYPES OF VALVE AND APPLICATION:
Ball Check Valves
Double Check Valves
Global Style Silent Check Valves
Hydraulic Check Valves
Submersible Check Valves
Ductile Iron Check Valves
Swing Check Valves
Wafer Check Valves
Stainless Steel Check Valves
Plastic Check Valves
Auto Drain Check Valves
There are a number of reasons for using check valves, which include:
Protection of any item of equipment that can be affected by reverse flow, such as flow meters, strainers and control valves.
To check the pressure surges associated with hydraulic forces, for example, water hammer. These hydraulic forces can cause a wave of pressure to run up and down pipe work until the energy is dissipated.
Prevention of flooding.
Prevention of reverse flow on system shutdown.
Prevention of flow under gravity.
Relief of vacuum conditions.
Although check valves can effectively shut off reverse flow, they should never be used in place of an isolation valve to contain live steam, in a section of pipe.
As with isolation valves, there are a number of different check valve designs, each suited to specific applications. The different types of check valve and their applications are discussed in this tutorial, along with the correct sizing method.
Ball Check Valves Ball check valves contain a ball that sits freely above the seat, which has only one through hole. The ball has a slightly larger diameter than that of the through hole. When the pressure behind the seat exceeds that above the ball, liquid is allowed to flow through the valve. But once the pressure above the ball exceeds the pressure below the seat, the ball returns to rest in the seat, forming a seal that prevents backflow.
Double check valve A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It is also a valve used in air brake systems on heavy trucks. Usage in Water Supply: In the case of usage in water supply, it consists of two check valves assembled in series. This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage. Small valves may be so compact as to be barely noticeable, particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, for isolation and testing. Often, test cocks (very small ball valves) are in place to attach test equipment for evaluating whether the double check assembly is still functional.
The double check valve assembly is suitable for prevention of back pressure and back siphon age, but is not suitable for high hazard applications. It is commonly used on lawn irrigation, fire sprinkler and combi boiler systems. If the hazard is higher, even a relatively low hazard such as using antifreeze in the fire sprinkler system, then a more reliable check valve such as a reduced pressure zone device may be mandated.
Hydraulic Check Valve The function of a check valve is to prevent flow in one direction and allow flow in the other direction. Check valves commonly use a poppet and light spring to control flow as shown in the figure below. If P 1A1> P2A2 + spring force + friction, then flow occurs in the direction of the arrows. If P1A1< P2A2 + spring force + friction, then the poppet would be pushed to the left, against the stop, prohibiting flow in the reverse direction. He most common method for deg a check valve is illustrated in the Figure 1. Different manufacturers may utilize other design approaches. For example, another type of check valve is a ball that pushes against a spring. Operation is similar to the check valve shown in Figure 1 except a ball replaces the piston. Check valves are used in hydraulic systems anytime flow in a selected direction is not desirable or may create a problem. Parallel Pump Installations – to prevent outlet flow from one pump at a slightly higher pressure from flowing to the other pump (see Figure 3). In this type of pump installation, one of the two check valves is designed to open at a slightly higher pressure than the other. For example, say the left pump is powered by the aircraft’s engine and the right pump is power by an electric motor. In this
type of application the engine driven pump generally has a larger flow capacity over that of the electrical driven pump. The electrical driven pump is intended as a backup for the engine driven pump. In this case the check valve on the electrical driven pump could be set to open (crack) about 50 psi more than the engine driven pump. This will ensure the engine driven pump supplies the system leakage flow during periods of no hydraulic flow demands and will also help reduce electrical motor noise variability. When considering the use of a check valve, the following factors should be evaluated: Pressure Rating – make sure the valve is rated appropriately for the system pressure Regulation Range – go into and out of the checked flow position Pressure Drop Across the Valve – this will affect design pressure available to downstream components and thus, the sizing of those components Temperature Rating – valve should be rated for fluid temperatures and applicable environmental temperatures Valve Materials – valve should be sufficient to proof and burst testing, not be susceptible to corrosion and other environmental considerations, operate properly under temperature extremes Seals/Clearances – affects overall reliability of the valve. Some valves may not use seals and will maintain tight clearances between piston and housing to minimize
leakage through the valve. The design characteristics can be affected by environmental conditions and aging/wear over time. Leakage – what is the leakage through the valve in the checked position under all environmental conditions? Failure Modes – the dominant failure modes consist of the piston jamming in either the open or the closed position. Clogging is also a possibility.
Lift check valves Lift check valves are similar in configuration to globe valves, except that the disc or plug is automatically operated. The inlet and outlet ports are separated by a cone shaped plug that rests on a seat typically metal; in some valves, the plug may be held on its seat using a spring. When the flow into the valve is in the forward direction, the pressure of the fluid lifts the cone off its seat, opening the valve. With reverse flow, the cone returns to its seat and is held in place by the reverse flow pressure. If a metal seat is used, the lift check valve is only suitable for applications where a small amount of leakage, under reverse flow conditions, is acceptable. Furthermore, the design of a lift check valve generally limits its use to water applications, subsequently they are commonly used to prevent reverse flow of condensate in steam traps and on the outlets of cyclic condensate pumps. The main advantage of the lift check valve lies in its simplicity, and as the cone is the only moving part, the valve is robust and requires little maintenance. In addition, the use of a metal seat limits the amount of seat wear. The lift check valve has two major limitations; firstly, it is designed only for installation in horizontal pipelines, and secondly, its size is typically limited to DN80.
The piston-type lift check valve is a modification of the standard lift check valve. It incorporates a piston shaped plug instead of the cone, and a dashpot is applied to this mechanism. The dashpot produces a damping effect during operation, thereby eliminating the damage caused by the frequent operation of the valve, for example, in pipeline systems, which are subject to surges in pressure, or frequent changes in flow direction (one example would be a boiler outlet).
Swing check valves A swing check valve consists of a flap or disc of the same diameter as the pipe bore, which hangs down in the flow path. With flow in the forwards direction, the pressure of the fluid forces the disc to hinge upwards, allowing flow through the valve. Reverse flow will cause the disc to shut against the seat and stop the fluid going back down the pipe. In the absence of flow, the weight of the flap is responsible for the closure of the valve; however, in some cases, closure may be assisted by the use of a weighted lever. As can be seen from Figure 12.3.2, the whole mechanism is enclosed within a body, which allows the flap to retract out of the flow path. Swing check valves produce relatively high resistance to flow in the open position, due to the weight of the disc. In addition, they create turbulence, because the flap 'floats' on the fluid stream. With abrupt changes in flow, the disc can slam against the valve seat, which can cause significant wear of the seat, and generate water hammer along the pipe system. This can be overcome by fitting a damping mechanism to the disc and by using metal seats to limit the amount of seat wear.
Wafer check valves Both lift and swing check valves tend to be bulky which limits their size and makes them costly. To overcome this, wafer check valves have been developed. By definition wafer check valves are those that are designed to fit between a set of flanges. This broad definition covers a variety of different designs, including disc check valves and wafer versions of swing or split disc check valves.
Disc check valves The disc check valve consists of four main components: the body, a disc, a spring and a spring retainer. The disc moves in a plane at right angles to the flow of the fluid, resisted by the spring that is held in place by the retainer. The body is designed to act as an integral centering collar that facilitates installation. Where a 'zero leakage' seal is required, a soft seat can be included. When the force exerted on the disc by the upstream pressure is greater than the force exerted by the spring, the weight of the disc and any downstream pressure, the disc is forced to lift off its seat, allowing flow through the valve. When the differential pressure across the valve is reduced, the spring forces the disc back onto its seat, closing the valve just before reverse flow occurs. This is shown in Figure. The presence of the spring enables the disc check vale to be installed in any direction.
Swing type wafer check valves These are similar to the standard swing check valves, but do not have the full-bodied arrangement, instead, when the valve opens, the flap is forced into the top of the pipeline. Subsequently, the flap must have a smaller diameter than that
of the pipeline, and because of this, the pressure drop across the valve.
Swing type check valves are used mainly on larger pipeline sizes, typically above DN125,
because on smaller pipelines the pressure drop, caused by the disc
'floating' on the fluid stream, becomes significant. Furthermore, there are significant cost savings to be made by using these valves on larger sizes, due to the small amount of material required for the construction of the valve. There is however one problem with using larger size valves; due to their size, the discs are particularly heavy, and therefore possess a large amount of kinetic energy when they close. This energy is transferred to the seat and process fluid when the valve slams shut, which could cause damage to the seat of the valve and generate water hammer.
Cast Iron Check Valves Flomaton Corporation manufactures Cast Iron Check Valves with high strength epoxy coated ductile iron body (1”-2” have cast steel body), disc and follower with threaded female x female connection. Flomaton’s ductile iron series 80DI are one of the most popular valves in the water well industry today. They are specifically designed for use with submersible pumps or other applications where it is necessary for the check valve to be installed in the well casing. The 80DI series valves will provide excellent service in any application where a conventional check valve is recommended and is vertically
mounted.
For
general
installations,
request
bulletin
#810.
Click on a link below to view cast iron check valve applications and specifications and to enter a RFQ.
Wafer check valve applications Wafer check valves are becoming the preferred type of check valve for most applications, due to their compact design and relatively low cost. The following is a list of some of their most common applications:
Boiler feed lines - The check valve is used to prevent boiler water being forced back along the feed line into the storage tank when the feed pump stops running. Furthermore, a disc check valve with a heavy-duty spring and a soft seat can be fitted in the boiler feed line to prevent flow under gravity into the boiler when the feed pump is shut off.
Steam traps - Other than with steam traps discharging to atmosphere, check valves should always be inserted after a steam trap to prevent back flow of condensate flooding the steam space. The check valve will also prevent the steam trap from becoming damaged by any hydraulic shock in the condensate line. It should be noted that when using blast discharge type steam traps, the check valve should be fitted at least 1 m downstream of the trap.
SELECTION OF CHECK VALVES
SELECTION OF CHECK VALVES Most check valves are selected qualitatively by comparing the required closing speed with the closing characteristic of the valve. This selection method leads to good results in the majority of applications. However, sizing is also a critical component of valve selection, as discussed in the following. If the application is critical, a reputable manufacturer should be consulted.
Check Valves for incompressible Fluids These are selected primarily for their ability to close without introducing an unacceptably high surge pressure due to the sudden shut-off of reverse flow. Selecting these for a low pressure drop across the valve is normally only a secondary consideration. The first step is qualitative assessment of the required closing speed for the check valve. Examples of how to assess the required closing speed in pumping installations are given in this page. The second step is the selection of the type of check valve likely to meet the required closing speed, as deduced from page.
Check Valves for Compressible Fluids Check valves for compressible fluids may be selected on a basis similar to that described for incompressible fluids. However, valve flutter can be a problem for high lift check valves in gas service.
FEED CHECK VALVE
FEED CHECK VALVE: A feed check valve is one of the important boiler mountings. It helps to regulate the supply of feed water to the boiler and thus enables to maintain constant water level. It is usually fitted in the feed pipe line close to the boiler shell so as to lie just below the normal water level. The feed water is pumped into the boiler through the feed check valve which prevents its flowing back due to pressure in the boiler. The following figure shows one of the simple types of the feed check valves used in the boiler feed systems. It is assembled to the feed water pipe line with its horizontal flange bolted to the flange of the inlet pipe and vertical flange bolted to the flange bolted to the flange of the delivery pipe. A gun metal valve seat in the part takes its seating on the valve seat such that its webs project sufficiently long into the valves seat so as to be well guided during its lift and fall. The amount of the feed water flowing through the check valve depends on the lift of the valve which in turn depends on the gap between the lower end of the spindle which is screwed through the cover and the top of the valve. This gap can be varied by turning the handle fitted at the top of the spindle and secured to it using a hexagonal nut and washer. The cover is fitted to the body by six studs and hexagonal nuts. To prevent the leakage of the steam between the spindle and the cover a gland is mounted on the cover, so as to retain the packing in the stuffing box provided in the cover, and connected to it by the studs and the hexagonal nuts.
Feed water Regulator Feed water is the water to be supplied into steam boiler. Requirement of feed water is regulated by ABMA (American Boiler Manufacturing Association). Water treatment is one of step in this requirement. Temperature of feed water influence
efficiency of steam boiler, higher temperature will increase the efficiency, so feed water heater is required in the feed water system. Amount of feed water is maintained to keep steam boiler on the range of NOWL (Normal Operation Water Level). Maintain water level is totally important to keep steam boiler safe from both short term overheating or long term overheating and also damage turbine generator. There are three types of feed water regulators commonly used in the power plant system. The type of feed water regulator is generally used based on function, size, and the principal working. The following below are the feed water regulator type
1.
Thermostatic Expansion Regulator This type is feed water regulator which uses inclined tube and connects it
between feed water control valve and boiler. If the water level in the boiler indicates low level, the tube will get expansion, so the feed water control valve will supply the feed water.
2.
Hydraulic Regulator This type is feed water regulator which consist tube, fin, and jacket. This regulator use tube which be connected between water column in the steam drum and feed water control valve. When water level show low level which means that amount of steam steam is higher than water, the steam will enter the tube, at the certain temperature and pressure, the valve will open to supply feed water into steam boiler.
3.
Float Regulator This type is feed water regulator which uses floating equipment like a ball and connects it to the boiler. The floating ball will move up and down parallel with water level in the boiler. A connecting system must be set up between this equipment and the feed water control to maintain the steam boiler water level in the range NOWL. 1. The boiler feed water regulator valve used in many power plants is required to transition from feed pump recirculation to operation of the unit. Not only is the valve used to initially fill the steam drum, it is also used to control flow during normal operation when the steam drum is under pressure. This valve, therefore, must address cavitations during initial operation and provide adequate range ability to address the entire feed water requirements. Turndowns of at least 75:1 are common.
APPLICATION
APPLICATION Building Maintenance Compressor Discharge Condensate Lines Chemical Processing Boiler Feed & Discharge Compressor Discharge Food Beverage & Drug Autoclaves Boiler Feed & Discharge Mining Boiler Feed & Discharge Mine Dewatering Petroleum Production & Refining Boiler Feed & Discharge Compressor Discharge Petroleum Production & Refining Pump Discharge Steam Lines Power Generation Boiler Feed & Discharge Compressor Discharge Primary Metals Chemical Lines Compressor Discharge
DESIGN AND ANALYSIS
DESIGN AND ANALYSIS The main objective of this project is to design and analysis the feed check valve. Here we take to analysis the feed check valves temp distribution on our design. The design model is done in the Pro.e software and the design part is saved in IGES format. It is imported to ansys software. The details of element attributes such as element type and material properties. Then the volume is meshed using meshing option load values (temp) are added to the required surfaces. The
solution is carried out using ansys solver. Finally the results are obtained by using general post processer.
Material and its properties: Material:
cast steel
Properties: Density:
7850 kg/mm^3
Specific heat:
419 J/kg k
Youngs modulus:
2.07*10^11 Gpa
Poisson ratio:
0.29
Thermal conductivity:
46.7 w/m’c
INTRODUCTION TO CAD/CAM
INTRODUCTION TO CAD/CAM CAD/CAM is a term which means computer-aided design and computeraided manufacturing. It is the technology concerned with the use of digital computers to perform certain functions in design and production. This technology is moving in the direction of greater integration of design and manufacturing, two activities which have traditionally been treated as district and separate functions in a production firm. Ultimately, CAD/CAM will provide the technology base for the computer-integrated factory of the future. Computer – aided design (CAD) can be defined as the use of computer systems to assist in the creation, modification, analysis, or optimization of a design. The computer systems consist of the hardware and software to perform the specialized design functions required by the particular firm. The CAD hardware typically includes the computer, one or more graphics display terminals, keyboards, and other peripheral equipment. The CAD software consists of the computer programs to implement computer graphics on the system plus application programs to facilitate the engineering functions of the company. Examples of these application programs include stress-strain analysis of components, dynamic response of mechanisms, heat-transfer calculations, and numerical control part programming.
THE DESIGN PROCESS
THE DESIGN PROCESS: The process of deg is characterized by six identifiable steps or phase 1. Recognition of need 2. Definition of problem 3. Synthesis 4. Analysis and optimization 5. Evaluation 6. Presentation
APPLICATION OF COMPUTERS FOR DESIGN: The various design-related tasks which are performed by a modern computer-aided design system can be grouped into four functional areas: 1. Geometric modeling 2. Engineering analysis 3. Design review and evaluation 4. Automated drafting
Geometric modeling In computer-aided design, geometric modeling is concerned with the computer- compatible mathematical description of the geometry of an object. The mathematical description allows the image of the object Components in an assembly, or highlight dimensions, or a host of other purposes
Engineering analysis CAD/CAM systems often include or can be interfaced to engineering analysis software which can be called to operate on the current design model. Examples of this type are 1. Analysis of mass properties 2. Finite element analysis The analysis may involve stress –strain calculations, heat-transfer computations, or the use of differential equations to describe the dynamic behavior of the system being designed. A steady state thermal analysis may be either linear, with constant material properties; or non linear, with material properties that depend on temperature. The thermal properties of most material do vary with temperature, so the analysis usually is non linear, including radiation effects also makes the analysis non linear.
INTRODUCTION ABOUT PRO-E AND ANALYSIS
INTRODUCTION ABOUT PRO-E AND ANALYSIS PRO-E: Pro-Engineer is a powerful application. It is ideal for capturing the design intent of your models because at its foundation is a practical philosophy. Founder of this Pro-Engineer is Parametric Technology Corporation. After this version they are released Pro-E 2000i2, Pro-E 2001, Pro-e Wildfire, Pro-e Wildfire2.0… pro-e 5.0.,In 2011, PTC rebranded Pro/Engineer as Creo Parametric. The current version of the software is 1.0. Pro/ENGINEER (Pro/E for short) is a commercial CAD/CAM package that is widely used in industry for CAD/CAM applications. It is one of the new generation of systems that not only over a full 3-D solid modeller, in contrast to purely 2-D and surface modellers, but also parametric functionality and full associativity. This means that explicit relationships can be established between design variables and changes can be Pro/ENGINEER is a feature based, parametric solid modeling program. As such, it's use is significantly different from conventional drafting programs. In conventional drafting (either manual or computer assisted), various views of a part are created in an attempt to describe the geometry.
ANSYS: The ANSYS program has many finite element analysis capabilities, ranging from a simple, linear, static analysis to a complex non – linear, transient dynamic analysis. A typical ANSYS analysis has three distinct steps: Building the model Applying loads and obtain the solution Review the results.
BUILDING THE MODEL:
Building a finite element model requires a more of an ANSYS ’s time than any other part of the analysis. First you specify the job name and analysis title. Then, define the element types, real constants, and material properties, and the model geometry.
DEFINING ELEMENT TYPES: The analysis element library contains more than 100 different element types. Each element type has a unique number and a prefix that identifies the element category. Example: beam, pipe, plant, shell, solid.
DEFINING ELEMENT REAL CONSTANTS: Element real constant are the properties that depend on the element type, such as cross sectional properties of a beam element. For example real constants for BEAM3 , the 2-d beam element, or area, moment of inertia(IZZ), height , shear deflection constant (SHEAR Z), initial strain (ISTRN) different elements of same type may have different real constant values.
DEFINING MATERIAL PROPERTIES: Most elements types require material properties.
Depending on the
application, material properties may be: Linear or non linear Isotropic, Arthotropic, or an isotropic Constant temperature or temperature – dependant As with element type and real constant, each set of material properties has a material reference number. The table of material reference number verses material
property set ids called material property table. Within, one analysis you may have multiple material properties set.
MATERIAL PROPERTY TEST: Although you can define material properties separately for each element analysis, the ANSY program enables you to store a material property set in an archival material library file, then retrieve the set and reuse it in multiple analysis. The material library files also enable several ANSYS to share common used material property data.
OVERVIEW OF MODEL GENERATION: The ultimate purpose of finite element analysis which to recreate mathematical the behavior of an actual engineering system. In other words, the analysis must be an accurate mathematical model of a physical prototype. In the broadest sense, this model comprises all the nodes, elements, material properties, real constant, boundary conditions, and other features that are used to represent the physical system. In ANSYS terminology, the term model generation usually takes on the narrower meaning of generating the nodes and elements that represent the spatial volume and connectivity of actual system.
Thus, model generation in this
discussion will mean the process of define the geometric configuration model’s nodes and elements. The ANSYS program offers you the following approaches to model generation: Creating a solid model within ANSYS. Using direct generation Reporting a model created in CAD system.
MESHING YOUR SOLID MODEL: The procedure for generating a mesh of nodes & elements consists of three main steps: Set the element attributes Set mesh controls Generate the mesh controls, The second step, setting mesh controls, is not always necessary because the default mesh controls are appropriate for many models. If no controls are specified, the program will use the default setting on the de size command to produce a free mesh. As an alternative, you can use the small size feature to produce a better quality free mesh.
FREE ARE MAPPED MESH: Before meshing the model, and even before building the model, it is important to think about whether a free mesh or a mapped mesh is appropriate for the analysis. A free mesh has no restrictions in of element shapes, and has no specified pattern applied to it. Compared to a free mesh, a mapped mesh is restricted in of the element shape it contains and the pattern of the mesh. A mapped area mesh contains either only quadrilateral or only triangular elements, while a mapped volume mesh contains only hexahedron elements. In addition, a mapped mesh typically has a regular pattern, with obvious rows of elements. If you want this type of mesh, you must build the geometry as series of fairly regular volumes and or areas that can accept a mapped mesh.
SETTING ELEMENT ATTRIBUTES: Before you generate a mesh of nodes and elements, you must first define the appropriate element attributes. That is, you must specify the following Element type Real constant set Material properties set
Element co-ordinate system: LOADING:
The main goal of finite element analysis is to examine how a structure or component response to certain loading condition. Specifying the proper loading conditions, therefore, a key stepping analysis. You can apply loads on the model in variety of ways in ANSYS program. LOADS:
The word loads in ANSYS terminology includes boundary. Coupled field loads are simple case of one of the above loads, where results from analysis are used as loads in another analysis. For examples you may apply magnetic forces calculated in magnetic field analysis are force loads in structural analysis.
HOW TO APPLY LOADS: You can apply loads most loads either on the solid model (on key points, line, areas) or on the finite element model ( on nodes and elements). For example, you can specify forces at a key point or a node. Similarly, you can specify
convections (and other surface loads) on lines and areas or nodes and element faces. No matter how you specify loads, the solver expects all loads to be in term of finite element model. Therefore if your specify loads on the solid model, the program automatically transfers them to the nodes and element at the beginning of the solution. SOLUTION:
In the solution phase of the analysis, the computer takes over and solves the simultaneous equations that the finite element method generates. The result of the solution is a nodal degree of freedom values, which form the primary solution, and b) derived values, which form the element solution. The element solution is usually calculated at the elements integration points. The ANSYS program writes the results to the database as well as to the result file. Several methods of solving the simultaneous equations are available in the ANSYS program: frontal solution, sparse direct solution, Jacobi Conjugate gradient (JCG solution, incomplete cholesky conjugate (ICCG) solution, preconditioned conjugate gradient (PCG) solution, automatic iterative solver option (ITER). The frontal solver is the default, but you can select a different solver.
POST PROCESSING: After building the model and obtaining the solution, you will want answers to some critical question: will the design really work when put to use? How high are the stresses in this region?
How does the temperature of this part vary with
time? What is the heat loss across my model? How does the magnetic flow
through this device? How does the placement of this object affect fluid flow? The post processors in the ANSYS program can help you find answer these questions and others. Post processing means reviewing the results of an analysis. it is probably the most important step in the analysis, because you are trying to understand how the applied loads affect your design, how good you finite element mesh is, and so on. DISPLAYING RESULTS GRAPHICALLY:
Graphics display is perhaps the most effective way to review results. You can display the following types of graphics in post1. Contour displays Deformed shape displays Vector displays Path plots Reaction force displays Particle flow traces.
INTRODUCTION TO STRUCTURAL ANALYSIS Structural analysis is probably the most common application of the finite element method.
The term structural (or structure) implies not only civil
engineering structures such as bridges and buildings, but also naval, aeronautical and mechanical structures such as ship hulls, aircraft bodies and machine housings, as well as mechanical components such as pistons, machine parts and tools.
Types of structural analysis: The seven types of structural analysis provided by ANSYS are given below.
1.
Static analysis: used to determine displacement, stresses etc. under static
loading conditions. Both linear and non-linear static analyses. Non – Linearity’s can include plasticity, stress stiffening, large deflection, large strain, hyper elasticity, surfaces, and creep. 2. Modal analysis: used to calculate the natural frequencies and mode shapes of a structure. Different mode extraction methods are available.
3.
Harmonic analysis: used to determine the response of a structure to
harmonically time varying loads.
4. Transient dynamic analysis: used to determine the response of a structure to arbitrarily time varying loads. All non-linearity’s mentioned under static analysis above are allowed.
5. Spectrum analysis: an extension of the model analysis, used to calculate stress and strain due to response spectrum or a PSD input (random vibrations). 6. Buckling analysis: used to calculate the buckling load and determine the buckling mode shape. Both linear (eigenvalue) buckling and non –linear buckling analyses are possible. 7. Explicit dynamic analysis – ANSYS provides an interface to the LS-Dyna explicit finite element programs is used to calculate fast solution for large deformation dynamics and complex problems.
INTRODUCTION TO THERMAL ANALYSIS: A steady state thermal analysis calculates the effects of steady thermal loads on a system or component. Engineer/analysts often perform a steady state analysis before doing a transient thermal analysis, to help establish initial conditions. A steady – state analysis also can be the last step of a transient thermal analysis, performed after all transient effects have diminished.
You use steady – state thermal analysis to determine temperatures, thermal gradients, heat flow rates, and thermal loads that do not vary over time cause heat fluxes in an object that. Such loads include the following.
Convections Radiations Heat Flow rates Heat fluxes (heat flow per unit area) Constant temperature boundaries.
FINITE ELEMENT ANALYSIS
FINITE ELEMENT ANALYSIS Finite element analysis (FEA) has become commonplace in recent years, and is now the basis of a multibillion dollar per year industry. Numerical solutions to even very complicated stress problems can now be obtained routinely using FEA, and the method is so important that even introductory treatments of Mechanics of Materials { such as these modules { should outline its principal features. In spite of the great power of FEA, the disadvantages of computer solutions must be kept in mind when using this and similar methods: they do not necessarily reveal how the stresses are influenced by important problem variables such as materials properties and geometrical features, and errors in input data can produce wildly incorrect results that may be overlooked by the analyst. Perhaps the most important function of theoretical modeling is that of sharpening the designer's intuition; s of finite element codes should plan their strategy toward this end, supplementing the computer simulation with as much closed-form and experimental analysis as possible. Finite element codes are less complicated than many of the word processing and spreadsheet packages found on modern microcomputers. Nevertheless, they are complex enough that most s do to program their own code. A number of prewritten commercial codes are available, representing a broad price range and compatible with machines from microcomputers to supercomputers1. However, s with specialized needs should not necessarily shy away from code development, and may the code sources available in such texts as that by Zienkiewicz2 to be a useful starting point. Most finite element software is written in Fortran, but some newer codes such as felt are in C or other more modern programming languages.
In practice, a finite element analysis usually consists of three principal steps:
1. Preprocessing: The constructs a model of the part to be analyzed in which the geometry is divided into a number of discrete sub regions, or \elements," connected at discrete points called nodes. Certain of these nodes will have displacements, and others will have prescribed loads. These models can be extremely time consuming to prepare, and commercial codes vie with one another to have the most friendly graphical \preprocessor" to assist in this rather tedious chore. Some of these preprocessors can overlay a mesh on a preexisting CAD .so that finite element analysis can be done conveniently as part of the computerized drafting-and-design process.
2. Analysis: The dataset prepared by the preprocessor is used as input to the finite element code itself, which constructs and solves a system of linear or nonlinear algebraic equations
K[ij] u[j] = F[i] Where u and f are the displacements and externally applied forces at the nodal points. The formation of the K matrix is dependent on the type of problem being attacked, and this module will outline the approach for truss and linear elastic stress analyses. Commercial codes may have very large element libraries, with elements appropriate to a wide range of problem types. One of FEA's
principal advantages is that many problem types can be addressed with the same code, merely by specifying the appropriate element types from the library.
3. Post processing: In the earlier days of finite element analysis, the would pore through reams of numbers generated by the code, listing displacements and stresses at discrete positions within the model. It is easy to miss important trends and hot spots this way, and modern codes use graphical displays to assist in visualizing the results. A typical postprocessor display overlay colored contours representing stress levels on the model.
PHOTOGRAPHY
PHOTOGRAPHY FEED CHECK VALVE
EXPLODED VIEW
ANALYSED VIEWS:
CONCLUSION
CONCLUSION The design of the project was successfully completed using pro/E. The problems, which emerged during the design of the machine where successfully over come using pro/E. The design of the project involved making use of most of the important features of pro/E is versatile and comprehensive software foe threedimensional solid modeling. Protrusion and cut are used as main feature to develop the components. The components are drawn very using PRO/E. We can change the size of the component easily by using parametric feature (i.e.) no need for redraw the components. Analysis has been completed by using the ansys software efficiently and quickly. From this we conclude that every work has been completed confidently with PRO/E and Ansys, and can draw and analyze any complicated machine drawing efficiently and quickly.
BIBLIOGRAPHY 1. PTC Series Manual for Pro-E. 2. Machine Drawing by K.R.Gopalakrishna 3. CAD/CAM by Groover. 4. Www. PTC. COM 5. Www. Mech.nwu.edu/ Pro-E /toc.htm 6. www.Ansys.com
CONTENTS Introduction Check valve definition Industrial application Types of valve and its application Selection of check valve Feed check valve Application Design and analysis explanation Introduction about pro-E and analysis Finite element analysis Photography Conclusion Reference
INTRODUCTION
INTRODUCTION In fast moving world the time is very important criteria. But in the manual program time takes more and more for every work in the world In the production department drawing is very important for design the various parts. In the manual work, its takes more time and is also very difficult to draw various components compare to CAD. So, to avoid these difficulties, CAD implements for quick & accurate design. Computer aided design have various packages are Auto CAD, Pro-E, etc. Auto CAD is using for 2D drawing and Pro-E is the latest implement in CAD, Which is especially using for 3D modeling. Most of the industry Pro-E is using for creating a new Design and modification of existing Design. Before to start the production we can visualize entire parts and assembly view of the model by using Pro-E. We were design the entire part of FEED CHECK VALVE and assembled it. Ansys software is used for analyzing the 3d modeling objects. The ANSYS program has much finite element analysis, capabilities, ranging from a simple, linear, static analysis to a complex non–linear, transient dynamic analysis.
CHECK VALVE
CHECK VALVE Check valves are mechanical valves that permit gases and liquids to flow in only one direction, preventing process flow from reversing. They are classified as one-way directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the valve closed. The mechanics of check valve operation are not complicated. Check (non-return) valves are installed in pipelines to allow flow in one direction only; helping to protect equipment and processes. The operation, benefits, applications and selection of different designs, including lift, disc, swing and wafer check valves are explained in this tutorial.
The printable version of this page has now been replaced by The Steam and Condensate Loop Book
View the complete collection of Steam Engineering Tutorials
Check valves, or non-return valves, are installed in pipeline systems to allow flow in one direction only. They are operated entirely by reaction to the line fluid and therefore do not require any external actuation. In this text, the expected, or desired direction of flow is termed 'forward flow', flow in the opposite direction is 'reverse
flow'.
INDUSTRIAL APPLICATION
INDUSTRIAL APPLICATION Pump The check valves on this steam locomotive are located under the small dome between the chimney and the main dome. check valves are often used with some types of pumps. Piston-driven and diaphragm pumps such as metering pumps and pumps for chromatography commonly use inlet and outlet ball check valves. These valves often look like small cylinders attached to the pump head on the inlet and outlet lines. Many similar pump-like mechanisms for moving volumes of fluids around use check valves such as ball check valves. The feed pumps or injectors which supply water to steam boilers are fitted with check valves to prevent backflow.
Industrial processes Check valves are used in many fluid systems such as those in chemical and power plants, and in many other industrial processes. Check valves are also often used when multiple gases are mixed into one gas stream. A check valve is installed on each of the individual gas streams to prevent mixing of the gases in the original source. For example, if a fuel and an oxidizer are to be mixed, then check valves will normally be used on both the fuel and oxidizer sources to ensure that the original gas cylinders remain pure and therefore nonflammable.
Domestic use Some types of irrigation sprinklers and drip irrigation emitters have small check valves built into them to keep the lines from draining when the system is
shut off. Also used with most home made snowmakers. Check valves used in domestic heating systems to prevent vertical convection, especially in combination with solar thermal installations, also are called gravity brake. Rainwater harvesting systems that are plumbed into the main water supply of a utility provider may be required to have one or more check values fitted to prevent contamination of the primary supply by rainwater.
The application of mathematics to the operation of check valves is of relatively recent origin. Pool, Porwit, and Carlton40 describe a calculation method for check valves with a hinged disc that involves setting up the equation of motion for the disc and applying to that the deceleration characteristic of the flowing fluid within the system. Before the equation of motion for the disc can be written, certain physical constants of the valve must be known. The calculation determines the reverse flow velocity at the instant of sudden shut-off.
TYPES OF VALVE AND APPLICATION
TYPES OF VALVE AND APPLICATION:
Ball Check Valves
Double Check Valves
Global Style Silent Check Valves
Hydraulic Check Valves
Submersible Check Valves
Ductile Iron Check Valves
Swing Check Valves
Wafer Check Valves
Stainless Steel Check Valves
Plastic Check Valves
Auto Drain Check Valves
There are a number of reasons for using check valves, which include:
Protection of any item of equipment that can be affected by reverse flow, such as flow meters, strainers and control valves.
To check the pressure surges associated with hydraulic forces, for example, water hammer. These hydraulic forces can cause a wave of pressure to run up and down pipe work until the energy is dissipated.
Prevention of flooding.
Prevention of reverse flow on system shutdown.
Prevention of flow under gravity.
Relief of vacuum conditions.
Although check valves can effectively shut off reverse flow, they should never be used in place of an isolation valve to contain live steam, in a section of pipe.
As with isolation valves, there are a number of different check valve designs, each suited to specific applications. The different types of check valve and their applications are discussed in this tutorial, along with the correct sizing method.
Ball Check Valves Ball check valves contain a ball that sits freely above the seat, which has only one through hole. The ball has a slightly larger diameter than that of the through hole. When the pressure behind the seat exceeds that above the ball, liquid is allowed to flow through the valve. But once the pressure above the ball exceeds the pressure below the seat, the ball returns to rest in the seat, forming a seal that prevents backflow.
Double check valve A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It is also a valve used in air brake systems on heavy trucks. Usage in Water Supply: In the case of usage in water supply, it consists of two check valves assembled in series. This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage. Small valves may be so compact as to be barely noticeable, particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, for isolation and testing. Often, test cocks (very small ball valves) are in place to attach test equipment for evaluating whether the double check assembly is still functional.
The double check valve assembly is suitable for prevention of back pressure and back siphon age, but is not suitable for high hazard applications. It is commonly used on lawn irrigation, fire sprinkler and combi boiler systems. If the hazard is higher, even a relatively low hazard such as using antifreeze in the fire sprinkler system, then a more reliable check valve such as a reduced pressure zone device may be mandated.
Hydraulic Check Valve The function of a check valve is to prevent flow in one direction and allow flow in the other direction. Check valves commonly use a poppet and light spring to control flow as shown in the figure below. If P 1A1> P2A2 + spring force + friction, then flow occurs in the direction of the arrows. If P1A1< P2A2 + spring force + friction, then the poppet would be pushed to the left, against the stop, prohibiting flow in the reverse direction. He most common method for deg a check valve is illustrated in the Figure 1. Different manufacturers may utilize other design approaches. For example, another type of check valve is a ball that pushes against a spring. Operation is similar to the check valve shown in Figure 1 except a ball replaces the piston. Check valves are used in hydraulic systems anytime flow in a selected direction is not desirable or may create a problem. Parallel Pump Installations – to prevent outlet flow from one pump at a slightly higher pressure from flowing to the other pump (see Figure 3). In this type of pump installation, one of the two check valves is designed to open at a slightly higher pressure than the other. For example, say the left pump is powered by the aircraft’s engine and the right pump is power by an electric motor. In this
type of application the engine driven pump generally has a larger flow capacity over that of the electrical driven pump. The electrical driven pump is intended as a backup for the engine driven pump. In this case the check valve on the electrical driven pump could be set to open (crack) about 50 psi more than the engine driven pump. This will ensure the engine driven pump supplies the system leakage flow during periods of no hydraulic flow demands and will also help reduce electrical motor noise variability. When considering the use of a check valve, the following factors should be evaluated: Pressure Rating – make sure the valve is rated appropriately for the system pressure Regulation Range – go into and out of the checked flow position Pressure Drop Across the Valve – this will affect design pressure available to downstream components and thus, the sizing of those components Temperature Rating – valve should be rated for fluid temperatures and applicable environmental temperatures Valve Materials – valve should be sufficient to proof and burst testing, not be susceptible to corrosion and other environmental considerations, operate properly under temperature extremes Seals/Clearances – affects overall reliability of the valve. Some valves may not use seals and will maintain tight clearances between piston and housing to minimize
leakage through the valve. The design characteristics can be affected by environmental conditions and aging/wear over time. Leakage – what is the leakage through the valve in the checked position under all environmental conditions? Failure Modes – the dominant failure modes consist of the piston jamming in either the open or the closed position. Clogging is also a possibility.
Lift check valves Lift check valves are similar in configuration to globe valves, except that the disc or plug is automatically operated. The inlet and outlet ports are separated by a cone shaped plug that rests on a seat typically metal; in some valves, the plug may be held on its seat using a spring. When the flow into the valve is in the forward direction, the pressure of the fluid lifts the cone off its seat, opening the valve. With reverse flow, the cone returns to its seat and is held in place by the reverse flow pressure. If a metal seat is used, the lift check valve is only suitable for applications where a small amount of leakage, under reverse flow conditions, is acceptable. Furthermore, the design of a lift check valve generally limits its use to water applications, subsequently they are commonly used to prevent reverse flow of condensate in steam traps and on the outlets of cyclic condensate pumps. The main advantage of the lift check valve lies in its simplicity, and as the cone is the only moving part, the valve is robust and requires little maintenance. In addition, the use of a metal seat limits the amount of seat wear. The lift check valve has two major limitations; firstly, it is designed only for installation in horizontal pipelines, and secondly, its size is typically limited to DN80.
The piston-type lift check valve is a modification of the standard lift check valve. It incorporates a piston shaped plug instead of the cone, and a dashpot is applied to this mechanism. The dashpot produces a damping effect during operation, thereby eliminating the damage caused by the frequent operation of the valve, for example, in pipeline systems, which are subject to surges in pressure, or frequent changes in flow direction (one example would be a boiler outlet).
Swing check valves A swing check valve consists of a flap or disc of the same diameter as the pipe bore, which hangs down in the flow path. With flow in the forwards direction, the pressure of the fluid forces the disc to hinge upwards, allowing flow through the valve. Reverse flow will cause the disc to shut against the seat and stop the fluid going back down the pipe. In the absence of flow, the weight of the flap is responsible for the closure of the valve; however, in some cases, closure may be assisted by the use of a weighted lever. As can be seen from Figure 12.3.2, the whole mechanism is enclosed within a body, which allows the flap to retract out of the flow path. Swing check valves produce relatively high resistance to flow in the open position, due to the weight of the disc. In addition, they create turbulence, because the flap 'floats' on the fluid stream. With abrupt changes in flow, the disc can slam against the valve seat, which can cause significant wear of the seat, and generate water hammer along the pipe system. This can be overcome by fitting a damping mechanism to the disc and by using metal seats to limit the amount of seat wear.
Wafer check valves Both lift and swing check valves tend to be bulky which limits their size and makes them costly. To overcome this, wafer check valves have been developed. By definition wafer check valves are those that are designed to fit between a set of flanges. This broad definition covers a variety of different designs, including disc check valves and wafer versions of swing or split disc check valves.
Disc check valves The disc check valve consists of four main components: the body, a disc, a spring and a spring retainer. The disc moves in a plane at right angles to the flow of the fluid, resisted by the spring that is held in place by the retainer. The body is designed to act as an integral centering collar that facilitates installation. Where a 'zero leakage' seal is required, a soft seat can be included. When the force exerted on the disc by the upstream pressure is greater than the force exerted by the spring, the weight of the disc and any downstream pressure, the disc is forced to lift off its seat, allowing flow through the valve. When the differential pressure across the valve is reduced, the spring forces the disc back onto its seat, closing the valve just before reverse flow occurs. This is shown in Figure. The presence of the spring enables the disc check vale to be installed in any direction.
Swing type wafer check valves These are similar to the standard swing check valves, but do not have the full-bodied arrangement, instead, when the valve opens, the flap is forced into the top of the pipeline. Subsequently, the flap must have a smaller diameter than that
of the pipeline, and because of this, the pressure drop across the valve.
Swing type check valves are used mainly on larger pipeline sizes, typically above DN125,
because on smaller pipelines the pressure drop, caused by the disc
'floating' on the fluid stream, becomes significant. Furthermore, there are significant cost savings to be made by using these valves on larger sizes, due to the small amount of material required for the construction of the valve. There is however one problem with using larger size valves; due to their size, the discs are particularly heavy, and therefore possess a large amount of kinetic energy when they close. This energy is transferred to the seat and process fluid when the valve slams shut, which could cause damage to the seat of the valve and generate water hammer.
Cast Iron Check Valves Flomaton Corporation manufactures Cast Iron Check Valves with high strength epoxy coated ductile iron body (1”-2” have cast steel body), disc and follower with threaded female x female connection. Flomaton’s ductile iron series 80DI are one of the most popular valves in the water well industry today. They are specifically designed for use with submersible pumps or other applications where it is necessary for the check valve to be installed in the well casing. The 80DI series valves will provide excellent service in any application where a conventional check valve is recommended and is vertically
mounted.
For
general
installations,
request
bulletin
#810.
Click on a link below to view cast iron check valve applications and specifications and to enter a RFQ.
Wafer check valve applications Wafer check valves are becoming the preferred type of check valve for most applications, due to their compact design and relatively low cost. The following is a list of some of their most common applications:
Boiler feed lines - The check valve is used to prevent boiler water being forced back along the feed line into the storage tank when the feed pump stops running. Furthermore, a disc check valve with a heavy-duty spring and a soft seat can be fitted in the boiler feed line to prevent flow under gravity into the boiler when the feed pump is shut off.
Steam traps - Other than with steam traps discharging to atmosphere, check valves should always be inserted after a steam trap to prevent back flow of condensate flooding the steam space. The check valve will also prevent the steam trap from becoming damaged by any hydraulic shock in the condensate line. It should be noted that when using blast discharge type steam traps, the check valve should be fitted at least 1 m downstream of the trap.
SELECTION OF CHECK VALVES
SELECTION OF CHECK VALVES Most check valves are selected qualitatively by comparing the required closing speed with the closing characteristic of the valve. This selection method leads to good results in the majority of applications. However, sizing is also a critical component of valve selection, as discussed in the following. If the application is critical, a reputable manufacturer should be consulted.
Check Valves for incompressible Fluids These are selected primarily for their ability to close without introducing an unacceptably high surge pressure due to the sudden shut-off of reverse flow. Selecting these for a low pressure drop across the valve is normally only a secondary consideration. The first step is qualitative assessment of the required closing speed for the check valve. Examples of how to assess the required closing speed in pumping installations are given in this page. The second step is the selection of the type of check valve likely to meet the required closing speed, as deduced from page.
Check Valves for Compressible Fluids Check valves for compressible fluids may be selected on a basis similar to that described for incompressible fluids. However, valve flutter can be a problem for high lift check valves in gas service.
FEED CHECK VALVE
FEED CHECK VALVE: A feed check valve is one of the important boiler mountings. It helps to regulate the supply of feed water to the boiler and thus enables to maintain constant water level. It is usually fitted in the feed pipe line close to the boiler shell so as to lie just below the normal water level. The feed water is pumped into the boiler through the feed check valve which prevents its flowing back due to pressure in the boiler. The following figure shows one of the simple types of the feed check valves used in the boiler feed systems. It is assembled to the feed water pipe line with its horizontal flange bolted to the flange of the inlet pipe and vertical flange bolted to the flange bolted to the flange of the delivery pipe. A gun metal valve seat in the part takes its seating on the valve seat such that its webs project sufficiently long into the valves seat so as to be well guided during its lift and fall. The amount of the feed water flowing through the check valve depends on the lift of the valve which in turn depends on the gap between the lower end of the spindle which is screwed through the cover and the top of the valve. This gap can be varied by turning the handle fitted at the top of the spindle and secured to it using a hexagonal nut and washer. The cover is fitted to the body by six studs and hexagonal nuts. To prevent the leakage of the steam between the spindle and the cover a gland is mounted on the cover, so as to retain the packing in the stuffing box provided in the cover, and connected to it by the studs and the hexagonal nuts.
Feed water Regulator Feed water is the water to be supplied into steam boiler. Requirement of feed water is regulated by ABMA (American Boiler Manufacturing Association). Water treatment is one of step in this requirement. Temperature of feed water influence
efficiency of steam boiler, higher temperature will increase the efficiency, so feed water heater is required in the feed water system. Amount of feed water is maintained to keep steam boiler on the range of NOWL (Normal Operation Water Level). Maintain water level is totally important to keep steam boiler safe from both short term overheating or long term overheating and also damage turbine generator. There are three types of feed water regulators commonly used in the power plant system. The type of feed water regulator is generally used based on function, size, and the principal working. The following below are the feed water regulator type
1.
Thermostatic Expansion Regulator This type is feed water regulator which uses inclined tube and connects it
between feed water control valve and boiler. If the water level in the boiler indicates low level, the tube will get expansion, so the feed water control valve will supply the feed water.
2.
Hydraulic Regulator This type is feed water regulator which consist tube, fin, and jacket. This regulator use tube which be connected between water column in the steam drum and feed water control valve. When water level show low level which means that amount of steam steam is higher than water, the steam will enter the tube, at the certain temperature and pressure, the valve will open to supply feed water into steam boiler.
3.
Float Regulator This type is feed water regulator which uses floating equipment like a ball and connects it to the boiler. The floating ball will move up and down parallel with water level in the boiler. A connecting system must be set up between this equipment and the feed water control to maintain the steam boiler water level in the range NOWL. 1. The boiler feed water regulator valve used in many power plants is required to transition from feed pump recirculation to operation of the unit. Not only is the valve used to initially fill the steam drum, it is also used to control flow during normal operation when the steam drum is under pressure. This valve, therefore, must address cavitations during initial operation and provide adequate range ability to address the entire feed water requirements. Turndowns of at least 75:1 are common.
APPLICATION
APPLICATION Building Maintenance Compressor Discharge Condensate Lines Chemical Processing Boiler Feed & Discharge Compressor Discharge Food Beverage & Drug Autoclaves Boiler Feed & Discharge Mining Boiler Feed & Discharge Mine Dewatering Petroleum Production & Refining Boiler Feed & Discharge Compressor Discharge Petroleum Production & Refining Pump Discharge Steam Lines Power Generation Boiler Feed & Discharge Compressor Discharge Primary Metals Chemical Lines Compressor Discharge
DESIGN AND ANALYSIS
DESIGN AND ANALYSIS The main objective of this project is to design and analysis the feed check valve. Here we take to analysis the feed check valves temp distribution on our design. The design model is done in the Pro.e software and the design part is saved in IGES format. It is imported to ansys software. The details of element attributes such as element type and material properties. Then the volume is meshed using meshing option load values (temp) are added to the required surfaces. The
solution is carried out using ansys solver. Finally the results are obtained by using general post processer.
Material and its properties: Material:
cast steel
Properties: Density:
7850 kg/mm^3
Specific heat:
419 J/kg k
Youngs modulus:
2.07*10^11 Gpa
Poisson ratio:
0.29
Thermal conductivity:
46.7 w/m’c
INTRODUCTION TO CAD/CAM
INTRODUCTION TO CAD/CAM CAD/CAM is a term which means computer-aided design and computeraided manufacturing. It is the technology concerned with the use of digital computers to perform certain functions in design and production. This technology is moving in the direction of greater integration of design and manufacturing, two activities which have traditionally been treated as district and separate functions in a production firm. Ultimately, CAD/CAM will provide the technology base for the computer-integrated factory of the future. Computer – aided design (CAD) can be defined as the use of computer systems to assist in the creation, modification, analysis, or optimization of a design. The computer systems consist of the hardware and software to perform the specialized design functions required by the particular firm. The CAD hardware typically includes the computer, one or more graphics display terminals, keyboards, and other peripheral equipment. The CAD software consists of the computer programs to implement computer graphics on the system plus application programs to facilitate the engineering functions of the company. Examples of these application programs include stress-strain analysis of components, dynamic response of mechanisms, heat-transfer calculations, and numerical control part programming.
THE DESIGN PROCESS
THE DESIGN PROCESS: The process of deg is characterized by six identifiable steps or phase 1. Recognition of need 2. Definition of problem 3. Synthesis 4. Analysis and optimization 5. Evaluation 6. Presentation
APPLICATION OF COMPUTERS FOR DESIGN: The various design-related tasks which are performed by a modern computer-aided design system can be grouped into four functional areas: 1. Geometric modeling 2. Engineering analysis 3. Design review and evaluation 4. Automated drafting
Geometric modeling In computer-aided design, geometric modeling is concerned with the computer- compatible mathematical description of the geometry of an object. The mathematical description allows the image of the object Components in an assembly, or highlight dimensions, or a host of other purposes
Engineering analysis CAD/CAM systems often include or can be interfaced to engineering analysis software which can be called to operate on the current design model. Examples of this type are 1. Analysis of mass properties 2. Finite element analysis The analysis may involve stress –strain calculations, heat-transfer computations, or the use of differential equations to describe the dynamic behavior of the system being designed. A steady state thermal analysis may be either linear, with constant material properties; or non linear, with material properties that depend on temperature. The thermal properties of most material do vary with temperature, so the analysis usually is non linear, including radiation effects also makes the analysis non linear.
INTRODUCTION ABOUT PRO-E AND ANALYSIS
INTRODUCTION ABOUT PRO-E AND ANALYSIS PRO-E: Pro-Engineer is a powerful application. It is ideal for capturing the design intent of your models because at its foundation is a practical philosophy. Founder of this Pro-Engineer is Parametric Technology Corporation. After this version they are released Pro-E 2000i2, Pro-E 2001, Pro-e Wildfire, Pro-e Wildfire2.0… pro-e 5.0.,In 2011, PTC rebranded Pro/Engineer as Creo Parametric. The current version of the software is 1.0. Pro/ENGINEER (Pro/E for short) is a commercial CAD/CAM package that is widely used in industry for CAD/CAM applications. It is one of the new generation of systems that not only over a full 3-D solid modeller, in contrast to purely 2-D and surface modellers, but also parametric functionality and full associativity. This means that explicit relationships can be established between design variables and changes can be Pro/ENGINEER is a feature based, parametric solid modeling program. As such, it's use is significantly different from conventional drafting programs. In conventional drafting (either manual or computer assisted), various views of a part are created in an attempt to describe the geometry.
ANSYS: The ANSYS program has many finite element analysis capabilities, ranging from a simple, linear, static analysis to a complex non – linear, transient dynamic analysis. A typical ANSYS analysis has three distinct steps: Building the model Applying loads and obtain the solution Review the results.
BUILDING THE MODEL:
Building a finite element model requires a more of an ANSYS ’s time than any other part of the analysis. First you specify the job name and analysis title. Then, define the element types, real constants, and material properties, and the model geometry.
DEFINING ELEMENT TYPES: The analysis element library contains more than 100 different element types. Each element type has a unique number and a prefix that identifies the element category. Example: beam, pipe, plant, shell, solid.
DEFINING ELEMENT REAL CONSTANTS: Element real constant are the properties that depend on the element type, such as cross sectional properties of a beam element. For example real constants for BEAM3 , the 2-d beam element, or area, moment of inertia(IZZ), height , shear deflection constant (SHEAR Z), initial strain (ISTRN) different elements of same type may have different real constant values.
DEFINING MATERIAL PROPERTIES: Most elements types require material properties.
Depending on the
application, material properties may be: Linear or non linear Isotropic, Arthotropic, or an isotropic Constant temperature or temperature – dependant As with element type and real constant, each set of material properties has a material reference number. The table of material reference number verses material
property set ids called material property table. Within, one analysis you may have multiple material properties set.
MATERIAL PROPERTY TEST: Although you can define material properties separately for each element analysis, the ANSY program enables you to store a material property set in an archival material library file, then retrieve the set and reuse it in multiple analysis. The material library files also enable several ANSYS to share common used material property data.
OVERVIEW OF MODEL GENERATION: The ultimate purpose of finite element analysis which to recreate mathematical the behavior of an actual engineering system. In other words, the analysis must be an accurate mathematical model of a physical prototype. In the broadest sense, this model comprises all the nodes, elements, material properties, real constant, boundary conditions, and other features that are used to represent the physical system. In ANSYS terminology, the term model generation usually takes on the narrower meaning of generating the nodes and elements that represent the spatial volume and connectivity of actual system.
Thus, model generation in this
discussion will mean the process of define the geometric configuration model’s nodes and elements. The ANSYS program offers you the following approaches to model generation: Creating a solid model within ANSYS. Using direct generation Reporting a model created in CAD system.
MESHING YOUR SOLID MODEL: The procedure for generating a mesh of nodes & elements consists of three main steps: Set the element attributes Set mesh controls Generate the mesh controls, The second step, setting mesh controls, is not always necessary because the default mesh controls are appropriate for many models. If no controls are specified, the program will use the default setting on the de size command to produce a free mesh. As an alternative, you can use the small size feature to produce a better quality free mesh.
FREE ARE MAPPED MESH: Before meshing the model, and even before building the model, it is important to think about whether a free mesh or a mapped mesh is appropriate for the analysis. A free mesh has no restrictions in of element shapes, and has no specified pattern applied to it. Compared to a free mesh, a mapped mesh is restricted in of the element shape it contains and the pattern of the mesh. A mapped area mesh contains either only quadrilateral or only triangular elements, while a mapped volume mesh contains only hexahedron elements. In addition, a mapped mesh typically has a regular pattern, with obvious rows of elements. If you want this type of mesh, you must build the geometry as series of fairly regular volumes and or areas that can accept a mapped mesh.
SETTING ELEMENT ATTRIBUTES: Before you generate a mesh of nodes and elements, you must first define the appropriate element attributes. That is, you must specify the following Element type Real constant set Material properties set
Element co-ordinate system: LOADING:
The main goal of finite element analysis is to examine how a structure or component response to certain loading condition. Specifying the proper loading conditions, therefore, a key stepping analysis. You can apply loads on the model in variety of ways in ANSYS program. LOADS:
The word loads in ANSYS terminology includes boundary. Coupled field loads are simple case of one of the above loads, where results from analysis are used as loads in another analysis. For examples you may apply magnetic forces calculated in magnetic field analysis are force loads in structural analysis.
HOW TO APPLY LOADS: You can apply loads most loads either on the solid model (on key points, line, areas) or on the finite element model ( on nodes and elements). For example, you can specify forces at a key point or a node. Similarly, you can specify
convections (and other surface loads) on lines and areas or nodes and element faces. No matter how you specify loads, the solver expects all loads to be in term of finite element model. Therefore if your specify loads on the solid model, the program automatically transfers them to the nodes and element at the beginning of the solution. SOLUTION:
In the solution phase of the analysis, the computer takes over and solves the simultaneous equations that the finite element method generates. The result of the solution is a nodal degree of freedom values, which form the primary solution, and b) derived values, which form the element solution. The element solution is usually calculated at the elements integration points. The ANSYS program writes the results to the database as well as to the result file. Several methods of solving the simultaneous equations are available in the ANSYS program: frontal solution, sparse direct solution, Jacobi Conjugate gradient (JCG solution, incomplete cholesky conjugate (ICCG) solution, preconditioned conjugate gradient (PCG) solution, automatic iterative solver option (ITER). The frontal solver is the default, but you can select a different solver.
POST PROCESSING: After building the model and obtaining the solution, you will want answers to some critical question: will the design really work when put to use? How high are the stresses in this region?
How does the temperature of this part vary with
time? What is the heat loss across my model? How does the magnetic flow
through this device? How does the placement of this object affect fluid flow? The post processors in the ANSYS program can help you find answer these questions and others. Post processing means reviewing the results of an analysis. it is probably the most important step in the analysis, because you are trying to understand how the applied loads affect your design, how good you finite element mesh is, and so on. DISPLAYING RESULTS GRAPHICALLY:
Graphics display is perhaps the most effective way to review results. You can display the following types of graphics in post1. Contour displays Deformed shape displays Vector displays Path plots Reaction force displays Particle flow traces.
INTRODUCTION TO STRUCTURAL ANALYSIS Structural analysis is probably the most common application of the finite element method.
The term structural (or structure) implies not only civil
engineering structures such as bridges and buildings, but also naval, aeronautical and mechanical structures such as ship hulls, aircraft bodies and machine housings, as well as mechanical components such as pistons, machine parts and tools.
Types of structural analysis: The seven types of structural analysis provided by ANSYS are given below.
1.
Static analysis: used to determine displacement, stresses etc. under static
loading conditions. Both linear and non-linear static analyses. Non – Linearity’s can include plasticity, stress stiffening, large deflection, large strain, hyper elasticity, surfaces, and creep. 2. Modal analysis: used to calculate the natural frequencies and mode shapes of a structure. Different mode extraction methods are available.
3.
Harmonic analysis: used to determine the response of a structure to
harmonically time varying loads.
4. Transient dynamic analysis: used to determine the response of a structure to arbitrarily time varying loads. All non-linearity’s mentioned under static analysis above are allowed.
5. Spectrum analysis: an extension of the model analysis, used to calculate stress and strain due to response spectrum or a PSD input (random vibrations). 6. Buckling analysis: used to calculate the buckling load and determine the buckling mode shape. Both linear (eigenvalue) buckling and non –linear buckling analyses are possible. 7. Explicit dynamic analysis – ANSYS provides an interface to the LS-Dyna explicit finite element programs is used to calculate fast solution for large deformation dynamics and complex problems.
INTRODUCTION TO THERMAL ANALYSIS: A steady state thermal analysis calculates the effects of steady thermal loads on a system or component. Engineer/analysts often perform a steady state analysis before doing a transient thermal analysis, to help establish initial conditions. A steady – state analysis also can be the last step of a transient thermal analysis, performed after all transient effects have diminished.
You use steady – state thermal analysis to determine temperatures, thermal gradients, heat flow rates, and thermal loads that do not vary over time cause heat fluxes in an object that. Such loads include the following.
Convections Radiations Heat Flow rates Heat fluxes (heat flow per unit area) Constant temperature boundaries.
FINITE ELEMENT ANALYSIS
FINITE ELEMENT ANALYSIS Finite element analysis (FEA) has become commonplace in recent years, and is now the basis of a multibillion dollar per year industry. Numerical solutions to even very complicated stress problems can now be obtained routinely using FEA, and the method is so important that even introductory treatments of Mechanics of Materials { such as these modules { should outline its principal features. In spite of the great power of FEA, the disadvantages of computer solutions must be kept in mind when using this and similar methods: they do not necessarily reveal how the stresses are influenced by important problem variables such as materials properties and geometrical features, and errors in input data can produce wildly incorrect results that may be overlooked by the analyst. Perhaps the most important function of theoretical modeling is that of sharpening the designer's intuition; s of finite element codes should plan their strategy toward this end, supplementing the computer simulation with as much closed-form and experimental analysis as possible. Finite element codes are less complicated than many of the word processing and spreadsheet packages found on modern microcomputers. Nevertheless, they are complex enough that most s do to program their own code. A number of prewritten commercial codes are available, representing a broad price range and compatible with machines from microcomputers to supercomputers1. However, s with specialized needs should not necessarily shy away from code development, and may the code sources available in such texts as that by Zienkiewicz2 to be a useful starting point. Most finite element software is written in Fortran, but some newer codes such as felt are in C or other more modern programming languages.
In practice, a finite element analysis usually consists of three principal steps:
1. Preprocessing: The constructs a model of the part to be analyzed in which the geometry is divided into a number of discrete sub regions, or \elements," connected at discrete points called nodes. Certain of these nodes will have displacements, and others will have prescribed loads. These models can be extremely time consuming to prepare, and commercial codes vie with one another to have the most friendly graphical \preprocessor" to assist in this rather tedious chore. Some of these preprocessors can overlay a mesh on a preexisting CAD .so that finite element analysis can be done conveniently as part of the computerized drafting-and-design process.
2. Analysis: The dataset prepared by the preprocessor is used as input to the finite element code itself, which constructs and solves a system of linear or nonlinear algebraic equations
K[ij] u[j] = F[i] Where u and f are the displacements and externally applied forces at the nodal points. The formation of the K matrix is dependent on the type of problem being attacked, and this module will outline the approach for truss and linear elastic stress analyses. Commercial codes may have very large element libraries, with elements appropriate to a wide range of problem types. One of FEA's
principal advantages is that many problem types can be addressed with the same code, merely by specifying the appropriate element types from the library.
3. Post processing: In the earlier days of finite element analysis, the would pore through reams of numbers generated by the code, listing displacements and stresses at discrete positions within the model. It is easy to miss important trends and hot spots this way, and modern codes use graphical displays to assist in visualizing the results. A typical postprocessor display overlay colored contours representing stress levels on the model.
PHOTOGRAPHY
PHOTOGRAPHY FEED CHECK VALVE
EXPLODED VIEW
ANALYSED VIEWS:
CONCLUSION
CONCLUSION The design of the project was successfully completed using pro/E. The problems, which emerged during the design of the machine where successfully over come using pro/E. The design of the project involved making use of most of the important features of pro/E is versatile and comprehensive software foe threedimensional solid modeling. Protrusion and cut are used as main feature to develop the components. The components are drawn very using PRO/E. We can change the size of the component easily by using parametric feature (i.e.) no need for redraw the components. Analysis has been completed by using the ansys software efficiently and quickly. From this we conclude that every work has been completed confidently with PRO/E and Ansys, and can draw and analyze any complicated machine drawing efficiently and quickly.
BIBLIOGRAPHY 1. PTC Series Manual for Pro-E. 2. Machine Drawing by K.R.Gopalakrishna 3. CAD/CAM by Groover. 4. Www. PTC. COM 5. Www. Mech.nwu.edu/ Pro-E /toc.htm 6. www.Ansys.com
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