Effects of Scatter in Bolt Preload of Pipe Flange Connections With Gaskets on Sealing Performance

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Mitsuhiro Matsumoto ◽  
Satoshi Nagata
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Flange Connection ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. It is necessary for evaluating the sealing performance of the pipe flange connections with the gaskets subjected to intemal pressure to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. This paper deals with the leakage of the pipe flange connections with a spiral wound gasket and that with a compressed sheet gasket tightened by the torque control method. The scatter in the axial bolt forces was measured in the experiments. The contact gasket stress distributions at the interfaces of the pipe flange connections with the gaskets were calculated under the measured axial bolt forces by using elasto-plastic finite element method (FEM) taking into account hysteresis and non-linearity in the stress-strain curves of the gaskets. The effects of the scatter in the axial bolt forces tightened by the torque control method on the gas leakage were also examined by using the actual pipe flange connections. As the result, a difference in an amount of gas leakage measured was found to be substantial between our study and PVRC procedure. By using the calculated contact gasket stress distributions under the internal pressure and the results of the leakage tests, the sealing performance was evaluated. It is found that the sealing performance is worse in the actual pipe flange connection than that evaluated by PVRC procedure.

Stress Analysis and the Sealing Performance Evaluation of Pipe Flange Connections With Gaskets Subjected to Internal Pressure and External Bending Moment: Effects of Scatter in Bolt Preload

2004 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Wataru Maezaki ◽  
Satoshi Nagata
Keyword(s):  
Finite Element Method ◽  
Internal Pressure ◽  
Control Method ◽  
Bending Moment ◽  
Torque Control ◽  
Stress Distributions ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Spiral Wound

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. It is necessary for evaluating the sealing performance of the pipe flange connections with the gaskets subjected to internal pressure and external bending moment to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. This paper deals with the leakage of the pipe flange connections with a spiral wound gasket subjected to internal pressure and external bending moment tightened by the torque control method. The scattered axial bolt forces were measured in the experiments. The contact gasket stress distributions at the interfaces between pipe flanges and the gasket were calculated under the measured axial bolt force by using elasto-plastic finite element method (FEM) taking into account hysteresis and non-linearity in the stress-strain curves of spiral wound gasket. The effects of the scatter in the axial bolt forces tightened by the torque control method on the gas leakage were also examined by using the actual pipe flange connections under internal pressure and external bending moment. By using the calculated contact stress distributions and the results of the leakage tests, the sealing performance was evaluated. It is found that the sealing performance is worse in the actual pipe flange connection than that evaluated by PVRC procedure.

FEM Stress Analysis and Sealing Performance in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Distributions ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Element Method

The contact gasket stress distributions of a non-circular flange connection with a compressed asbestos sheet gasket subjected to internal pressure were analyzed taking account a hysteresis of the gasket by using finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed asbestos sheet gasket under internal pressure. By using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. A difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated. abstract text here.

Evaluation of the Sealing Performance in Bolted Flange Connection Under Heat Condition and Internal Pressure: The Effect of Scatter in Bolt Preloads

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshio Takagi ◽  
Katsuhiro Yamada
Keyword(s):  
Internal Pressure ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Heat Condition ◽  
Flange Connection ◽  
Gas Leakage ◽  
Sealing Performance ◽  
Torque Wrench ◽  
Bolted Flange

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. It is necessary for evaluating the sealing performance of the pipe flange connections with the gaskets subjected to internal pressure to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. Especially, when gases are used in the pipe flange connections with gaskets at a high temperature, it is necessary to evaluate the amount of gas leakage. In this study, when bolts and nuts in a pipe flange connection were tightened using a torque wrench, the axial bolt forces were measured and then the amount of gas leakage in the pipe flange connection at 50,100,150 and 200 °C was measured under internal pressure. Leakage tests were performed using Helium gases. In addition, the thermal stress distributions at the interfaces between pipe flanges and the gasket under heat condition (temperature 50,100,150 and 200 °C) and internal pressure were calculated by using the finite element method (FEM) taking into account hysteresis in the stress-strain curves of a spiral wound gasket. By using the calculated contact stress distributions and the results of the leakage tests, the sealing performance was evaluated.

Effects of Scatter in Bolt Preload on the Sealing Performance of Pipe Flange Connections Under Internal Pressure (Case Where the Nominal Diameter of Pipe Flange Connection is 20″)

2010 ◽  
Author(s):  
Yoshio Takagi ◽  
Toshiyuki Sawa ◽  
Hiroyasu Torii ◽  
Yuya Omiya
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Flange Connection ◽  
Nominal Diameter ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Contact Stress Distribution

It has been well known that a scatter in axial bolt forces in pipe flange connections tightened by the torque control method is substantial. In practice, pipe flange connections with the large nominal diameter tightened by the torque control method have been used in chemical industry, and so on. In our study, the characteristics of the connections with smaller nominal diameter (less than 8″) have been shown. So, in an optimum design of pipe flange connections with gaskets, it is necessary to understand the characteristics of the pipe flange connections with large nominal diameter under internal pressure and the contact gasket stress distributions due to the scatter in axial bolt forces in the connections tightened by the torque control method. In this paper, the experimental and FE analyses were done to evaluate the effect of scatter in axial bolt force on the gasket stress distribution and the sealing performance of pipe flange connections with 20″ nominal diameter. Two types of torque controlled assembling procedures, that is, ASME PCC-1 and JIS B 2251 procedures, are evaluated as an assembling procedures and an effect of scatter in the axial bolt forces obtained from the above methods is examined. Then, the effect of scatter in the axial bolt forces on the sealing performance of the connection is evaluated. The contact stress distribution in the larger pipe flange connection with 20″ nominal diameter under internal pressure is analyzed using FEM by taking into account a non-linearity and a hysteresis. The measured scatter in the axial bolt forces is applied in the FEM calculations.

FEM Stress Analysis and an Evaluation of the Sealing Performance in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference

The contact gasket stress distributions of a non-circular flange connection with a compressed sheet gasket subjected to internal pressure were analyzed taking into account of the hysteresis behavior of the gasket by using the finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed sheet gasket under internal pressure. Using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

Effects of Scatter in Bolt Preload on the Sealing Performance in Bolted Flange Connections With Cover of Pressure Vessel Under Internal Pressure

2006 ◽  
Author(s):  
Satoshi Nagata ◽  
Toshiyuki Sawa ◽  
Seiichi Hamamoto
Keyword(s):  
Internal Pressure ◽  
Pressure Vessel ◽  
Torque Control ◽  
Control Methods ◽  
Stress Distributions ◽  
Flange Connection ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Bolted Flange

It has been well known that the scatter in axial bolt forces of bolted flange connections tightened by torque control methods is substantial. In evaluating the sealing performance of a bolted flange connection with a gasket subjected to internal pressure, it is necessary to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the flange connections tightened by torque control methods. This paper deals with the leakage of a bolted flange connection with a cover of pressure vessel including a spiral wound gasket tightened by a torque wrench. The scatter in the axial bolt forces was measured using strain gauges attached at the shank of bolts. The amount of leakage from the bolted flange connection with cover of pressure vessel was measured by so-called pressure decay method. The gas employed was Helium. From the measured leakage, the actual assembly efficiency is examined. The eight bolts and nuts were tightened according to the ASME PCC-1 method and Japanese method developed by High Pressure Institute (HPI). The difference in the bolt preload was shown between the ASME method and the HPI method. The contact gasket stress distributions at the interface of the flange connection with the gasket were calculated under the measured axial bolt forces by means of finite element analysis. Using the calculated gasket contact stress distribution, the amount of gas leakage was estimated. The estimated gas leakage was compared with the measured results.

Stress Analysis and Sealing Performance Evaluation in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2004 ◽  
Author(s):  
Wataru Maezaki ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Performance Evaluation ◽  
Internal Pressure ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference

The contact gasket stress distributions of a non-circular flange connection with a compressed asbestos sheet gasket subjected to internal pressure were analyzed taking into account of the hysteresis behaviors of the gasket by using the finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed asbestos sheet gasket under internal pressure. Using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

Effects of Scatter in Bolt Preload of Pipe Flange Connections With Spiral Wound Gaskets Under Internal Pressure: In Case of Larger Pipe Flange Connection With 20" Nominal Diameter

2004 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Wataru Maezaki
Keyword(s):  
Internal Pressure ◽  
Contact Stress ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Gas Leakage ◽  
Nominal Diameter ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Helium Gas

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. In practice, pipe flange connections with the larger nominal diameter tightened by the torque control method have been used, frequently. So, in an optimum design of pipe flange connections with gaskets, it is necessary to understand the characteristics of the pipe flange connections with larger nominal diameter under internal pressure and the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. In this paper, the leakage tests were performed in the actual larger pipe flange connections with 20” nominal diameter using helium gas. Then, the effects of the scatter in the axial bolt forces tightened by the torque control method on the gas leakage were also examined. By using the calculated contact stress distributions and the results of the leakage tests, the sealing performance was evaluated.

FEM Calculation and Evaluation of Sealing Performance in Oil Pan Wavy-Shaped Flange Gasketed Connections

2011 ◽  
Author(s):  
Ryou Kurosawa ◽  
Kentaro Tenma ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Design Method ◽  
Light Weight ◽  
Stress Distributions ◽  
Flange Connection ◽  
Sealing Performance ◽  
Bolt Spacing ◽  
Good Agreement

The oil pan wavy-shaped flange connection, while is a type of the box-shaped flange connections, has been used for the oil-pan in the vehicles such as cars and motorcycles to seal inner fluid. Though the light weight of these connections is important, the design method has not been established, since no research for evaluating the sealing performance of the wavy-shaped flange connections has been conducted. In this paper, The contact gasket stress distribution in a oil pan wavy-shaped flange connection under the internal pressure is examined taking into account a gasket hysteresis using finite element method (FEM) for estimating a location where a principal leakage occurs and for calculating the amount of leakage. Leakage tests were also conducted to validate the estimated results using an actual connection under internal pressure. The effects of flange shape and difference in types of inner fluid (gas / liquid) are examined on the contact gasket stress distributions and the sealing performance in the connections. It is found that the estimated amount of leakage is in a fairly good agreement with the measured results. Furthermore, discussion on the effect of the bolt spacing and the gasket width on the sealing performance are made.

FEM Analysis and an Evaluation of the Sealing Performance in Flexible Box-Shape Flanged Bolted Joints With Gaskets Subjected to Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Yasuaki Tatsumi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Fem Analysis ◽  
Bolted Joints ◽  
Stress Distributions ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference ◽  
Element Method

The contact gasket stress distributions of rectangular box-shape flange connections with compressed joint sheet gaskets subjected to internal pressure were analyzed taking account hysteresis of the gaskets using finite element method (FEM). Leakage tests were also conducted using actual rectangular box-shape flange connections with compressed joint sheet gaskets under internal pressure. By using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

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