DESIGN AND ANALYSIS OF GATE VALVE BODY AND SEAT RING

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International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 3, March 2017, pp. 131–141 Article ID: IJMET_08_03_015 Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed

DESIGN AND ANALYSIS OF GATE VALVE BODY AND SEAT RING

S. Sathishkumar Assistant Professor, Department of Mechanical Engineering,

Vel Tech, Avadi, Chennai, Tamil Nadu, India

R. Hemanathan UG. Scholar, Department of Mechanical Engineering,


R. Gopinath UG. Scholar, Department of Mechanical Engineering,


D. Dilipkumar UG. Scholar, Department of Mechanical Engineering,


ABSTRACT Gate valves are used when a straight-line flow of fluid and minimum restriction is

desired. Gate valves are so named because the part that either stops or allows flow of fluid through the valve acts somewhat like the opening or closing of a gate and is called, appropriately, the gate. This gate valve is widely used in various industries like refineries, petrochemical complexes, fertilizer plants, power generation plants (hydro - electric, thermal and nuclear) steel plants and allied industries etc. for a various process. The objective of this project is to perform a stress analysis and temperature distribution of valve body of the Gate Valve. The seat ring is welded with the valve body by using gas tungsten arc welding. A model of body and seat ring of Gate Valve is developed in SOLID WORKS 2014, and analyzed in ANSYS 15. Gate valve stress analysis and temperature distribution is done by Finite Element Method using ANSYS 15. The main purpose is to create a model of the gate valve body and analysis the load deformation, stress concentration, temperature distribution and directional heat flow in the valve body at the place where the seat ring is welded. Key words: gate valve, temperature distribution, tungsten arc welding, SOLID WORKS 2014, ANSYS 15. Cite this Article: S. Sathishkumar, R. Hemanathan, R. Gopinath and D. Dilipkumar, Design and Analysis of Gate Valve Body and Seat Ring. International Journal of Mechanical Engineering and Technology, 8(3), 2017, pp. 131–141. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3

Design and Analysis of Gate Valve Body and Seat Ring


1. INTRODUCTION

1.1. Gate Valve A gate valve also known as a sluice valve is a valve which opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats are planar, so gate valves are often used when a straight-line flow of fluid and minimum restriction is desired. The gate faces can be parallel, but are most commonly wedge-shaped. Gate valves are primarily used to permit or prevent the flow of liquids, but typical gate valves shouldn't be used for regulating flow, unless they are specifically designed for that purpose. Because of their ability to cut through liquids, gate valves are often used in the petroleum industry. For extremely thick fluids, a specialty valve often known as a knife gate valve is used to cut through the liquid. On opening the gate valve, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening. This means that flow rate does not change evenly with stem travel. Also a partially open gate tends to vibrate from the fluid flow. Most of the flow change occurs near shutoff with a relatively high fluid velocity causing gate and seat wear and eventual leakage if used to regulate flow. Typical gate valves are designed to be fully opened or closed. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss.

Figure 1 Gate Valve

Gate valves are actuated by a threaded stem which connects the actuator (e.g. hand wheel or motor) to the gate. They are characterized as having either a rising or a non rising stem, depending on which end of the stem is threaded. Rising stems are fixed to the gate and rise and lower together as the valve is operated, providing a visual indication of valve position. The actuator takes the form of a nut which is rotated around the threaded stem to move it. Non rising stem valves are fixed to, and rotate with, the actuator, and are threaded into the gate. They may have a pointer threaded onto the upper end of the stem to indicate valve position, since the gate's motion is concealed inside the valve. Non rising stems are used underground or where vertical space is limited. Gate valves are primarily designed to serve as isolation valves. In service, these valves generally are either fully open or fully closed. When fully open, the fluid or gas flows through the valve in a straight line with very little resistance. It should not be used in the regulation or throttling of flow because accurate control is not

S. Sathishkumar, R. Hemanathan, R. Gopinath and D. Dilipkumar


possible. Furthermore, high-flow velocity in partially opened valves may cause erosion of the discs and seating surfaces. Vibration may also result in chattering of the partially opened valve disc. An exception to the above are specially designed gate valves that are used for low-velocity throttling; for example, guillotine gate valves for pulp stock.

1.2. Seat Ring The valve seat is a surface inside the body of a valve that comes into contact with the disk, which is a moveable component that restricts and allows flow through the valve. The valve seat has several important purposes, including:

Preventing compressed or combustion gasses from getting into the manifold.

Permitting a particular amount of heat to travel through the valve to the cylinder head.

Maintaining the proper seal of a mounted valve.

Reducing wear-resistance by resisting pressure and high heat. The valve seat ring creates a shutoff surface. Typically held in place by pressure, a seat

ring may also be threaded and screwed into the valve body. The valve seat ring is a crucial part for maintaining the strength of the seal within the valve and facilitating a seal that is free of leaks

Figure 2 Seat Ring

2. METHODOLOGY Methodology is the systematic, theoretical analysis of the methods applied to a field of study. It comprises the theoretical analysis of the body of methods and principles associated with a branch of knowledge.



3. MATERIALS The material used for the valve body and seat ring and then for the base material are as follows

The material used is ASTM A216 grade WCB is a type of ASTM A216 cast steel.

Table 1 Material properties

S/NO MATERIAL PROPERTIES RANGES 1 Young’s Modulus 210 Gpa 2 Poisson Ratio 0.29 3 Specific heat capacity 450 J/kg-K 4 Thermal Expansion 12 µm/m-K 5 Tensile Strength(UTS) 570Mpa 6 Tensile Strength(proof) 290 Mpa 7 Density 7.8 g/cm3 8 Strength to Weight Ratio 73 kN-m/kg 9 Specific heat capacity 450 J/kg-K 10 Modulus of Resilience 200 kJ/m3



4. PROCESS

4.1. Pre Heating of the Filler Material Preheating involves heating the base metal, either in its entirety or just the region surrounding the joint, to a specific desired temperature, called the preheat temperature, prior to welding. Heating may be continued during the welding process, but frequently the heat from welding is sufficient to maintain the desired temperature without a continuation of the external heat source. The interpass temperature, defined as the base metal temperature between the first and last welding passes, cannot fall below the preheat temperature. Interpass temperature will not be discussed further here.

There are four primary reasons to utilize preheat: (1) It lowers the cooling rate in the weld metal and base metal, (2) The slower cooling rate provides an opportunity for any hydrogen that may be present to diffuse out harmlessly without causing cracking (3) It reduces the shrinkage stresses in the weld and adjacent base metal, which is especially important in highly restrained joints. (4) It raises some steels above the temperature at which brittle fracture would occur in fabrication.

Table 2 Preheat and Inter pass Temperatures

Thickness (In.) Minimum Preheat and Inter pass Temperature

(F)

Maximum Preheat and Inter pass Temperature

(F)

Up to ¾ 50 400 ¾ to 1½ 125 400

1½ to 2½ 175 400 More than 2½ 225 400

Additionally, preheat can be used to help ensure specific mechanical properties, such as notch toughness.

4.2. Welding of the Seat Ring with the Gate Valve The gate valve body is welded with the seat ring by using the gas tungsten arc welding process and also by various process like metal inert gas welding and also by friction arc welding. Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by an inert shielding gas (argon or helium), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it.



Figure 3 Gas tungsten arc welding Figure 4 Friction arc welding

4.3. Heating the Valve in the Furnace After the welding process the valve body is heated in the furnace in order to avoid stress concentration in the welded area and to avoid the uneven temperature distribution in the valve body. A furnace is a device used for high-temperature heating. The name derives from Greek word fornax, which means oven. The heat energy to fuel a furnace may be supplied directly by fuel combustion, by electricity such as the electric arc furnace, or through induction heating in induction furnaces. The valve body is heated in the furnace at a temperature of 650°C for 3-4 hours.

Figure 5 furnaces

5. MODELLING

5.1. Gate Valve Solid modeling finds wide applications that cut across functional boundaries such as use of solid modeling in finite element analysis. Further more solid models are used to evaluate the size, shape and weight of products early during the conceptual design phase.

The modeling of components of gate valve is carried out using SOLID WORKS 2014 Solid Works (stylized as SOLIDWORKS) is a solid modeling computer-aided design

(CAD) and computer-aided engineering (CAE) computer program that runs on Microsoft Windows. Solid Works is published by Dassault System



Figure 6 Drawing sheet of the valve body Figure 7 Gate Valve Model

5.2. Seat Ring

Figure 8 Drawing sheet of the seat ring Figure 9 Seat ring model

6. FINITE ELEMENT ANALYSIS

6.1. Before Problem Identification The finite element method (FEM) is a numerical method for solving problems of engineering and mathematical physics. Here The FEA is done by the ANSYS work bench

Figure 10 Valve body after meshed Figure 11 Total deformation of the valve body



7. PROBLEM IDENTIFICATION AND SOLUTION After the welding of the seat ring with the valve body there will be many uneven stress concentration and uneven temperature distribution

7.1. Welding Defects Cracks Undercut Distortion

7.2. Solution The remedy for the following problem identified the valve body after welding with the seat ring is heated in the furnace to make even temperature distribution and even stress concentration in the valve body .A furnace is a device used for high-temperature heating. The heat energy to fuel a furnace may be supplied directly by fuel combustion, by electricity such as the electric arc furnace, or through induction heating in induction furnaces.

8. RESULT AND DISCUSSION

8.1. After Problem Rectification

8.1.1. Valve Body during Static Structural Analysis

Figure 12 Total deformation of the valve body after welding

Figure 13 Equivalent stress (von mises stress) in the valve body and seat ring after welding



Figure 14 Principle stress in the valve body after welding

8.1.2. Valve Body Using Steady State Thermal Analysis

Figure 15 Temperature distribution at the valve body after welding

Figure 16 Total heat flux on the valve body after welding

Figure 17 Directional heat flux in the valve body after welding with the seat ring



8.1.3. Analysis of the Valve after Heating in Furnace

Figure 18 Total heat flux in the valve body after heating in the furnace

Figure 19 Total deformation in the valve body after heating in the furnace

9. CONCLUSION Thus the body of the gate valve which is known as valve body and seat ring is modeled by using the modeling software SOLIDWORKS and then it is analyzed using the Finite Element Analysis software ANSYS for various aspects such as total deformation, equivalent stress(von mises stress), maximum principle stress for stress concentration and then temperature, total heat flux, directional heat flow for temperature distribution are analyzed and then to avoid some welding defects like crack, distortion, undercut, overlap the valve body is heated in the furnace and this heating of the valve body is also analyzed with the finite element analysis software

REFERENCES

[1] Mr. Pradip Bhaskar Patil, Prof. V. R. Gambhire “Structural Analysis of Gate Valve Body Using F.E.A.” International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Vol. 3 Issue 6, June – 2014.

[2] Klaus-Dieter Schoenborn, “Fatigue Analysis of a Welded Assembly Using ANSYS Workbench Environment” ANSYS Service @ CADFEM GmbH, Germany.

[3] Dr. K.H. Jatkar, Sunil S. Dhanwe, “Finite Element Analysis of Gate Valve” International Journal of Engineering and Innovative Technology (IJEIT) Volume 2, Issue 10, April 2013.

[4] Pujari A.A1, Joshi G.S2, “Anyalysis and Design Optimization of 8’’- 600# Gate Valve Body Using Fea and Stress Anylasis” International Journal of Research in Engineering and Technology.



[5] Sonali Mantati1, A. N. Surde2, “Finite Element Analysis of Flexible Wedge Type (2”#150) Gate Valve” International Journal of Emerging Technology and Advanced Engineering, Volume 5, Issue 6, June 2015.

[6] S. Sathishkumar, Dr. M. Kannan, P. Amirthalingam, S. Arunkumar and N.S. Natesh, Material Development for Thermo Mechanical Strained Structural Application. International Journal of Mechanical Engineering and Technology , 7(6), 2016, pp. 236–244

[7] Shubham Srivastava, Kiran Shet and Satish Kulkarni. A comparative study of two methodologies for nonlinear finite element analysis of knife edge gate valve sleeve, International Journal of Mechanical Engineering and Technology, 6(12), 2015, pp. 81-90.

AUTHOR DETAILS

S. Sathishkumar is currently a Assistant Professor in the Department of Mechanical Engineering Vel Tech Avadi, Chennai-600062, Tamilnadu, India. He Received his BE (Mechanical Engineering) in Asan Memorial College of Engineering & Technology, Chengalpet, Tamilnadu, India and ME (Engineering Design) From SKP Engineering College, Tiruvannamalai, Tamilnadu, India. He has Published 9 International Journal 4 Papers in International Conferences and 1 National Conferences

R. Hemanathan, Final year UG Student, Department of Mechanical Engineering ,Vel Tech, Avadi,Chennai-62, Tamilnadu, India

R. Gopinath, Final year UG Student, Department of Mechanical Engineering ,Vel Tech Avadi ,Chennai-62, Tamilnadu, India

D. Dilipkumar, Final year UG Student, Department of Mechanical Engineering, Vel Tech Avadi, Chennai-62, Tamilnadu, India