Influence of Loading Rate on Deformation Behaviour and Sealing Performance of Spiral Wound Gasket in Flange Joint

2017 ◽  
pp. 83-93
Author(s):  
N. Rino Nelson ◽  
N. Siva Prasad ◽  
A. S. Sekhar
Keyword(s):  
Loading Rate ◽  
Deformation Behaviour ◽  
Flange Joint ◽  
Sealing Performance ◽  
Spiral Wound

Application of Plastic Region Bolt Tightening to Flange Joint Assembly: Behavior of Large Diameter Flange

2009 ◽  
Author(s):  
Shinobu Kaneda ◽  
Hirokazu Tsuji
Keyword(s):  
Internal Pressure ◽  
Large Diameter ◽  
Plastic Region ◽  
Load Factor ◽  
Past Study ◽  
Flange Joint ◽  
The Past ◽  
Sealing Performance ◽  
Assembly Behavior ◽  
Bolted Flange

In the past study the plastic region tightening has been applied to the bolted flange joint with smaller nominal diameter and its advantages have been demonstrated, however, behavior of the bolted flange joint with larger diameter is not investigated. Flange rotation of the bolted flange joint with large diameter increases when the internal pressure is applied. Gasket stress is not uniform and it may cause leak accident. So, it is necessary to investigate the behavior of the larger diameter flange. The present paper describes the behavior of bolted flange joint with large diameter under plastic region tightening. Firstly, API 20-inch flange joint tightened to the plastic region by bolt with a smaller diameter and superiority in the uniformity of the axial bolt force is demonstrated. And then the internal pressure is applied to the bolted flange joint and the behavior of the additional axial bolt force is demonstrated. The axial bolt force decreases with increasing the internal pressure, and the load factor is negative due to increasing of the flange rotation. However, the load factor of the bolted flange joint tightened to the plastic region by using the bolt with the smaller diameter approached zero. Using the bolts with smaller diameter is advantageous to the flange joint with the larger diamter, whose load factor is negative, to prevent the leakage. Additionally, the leak rate from the bolted flange joint is measured and the sufficient sealing performance is obtained.

Impact of Including Spiral Wound Bead Width in Gasket Area

2019 ◽  
Author(s):  
Kathryn Worden ◽  
Mark Ruffin
Keyword(s):  
Outer Diameter ◽  
Full Width ◽  
Bolted Joint ◽  
Bead Width ◽  
Sealing Performance ◽  
Narrow Width ◽  
Winding Wire ◽  
Sealing Elements ◽  
Area Determination ◽  
Spiral Wound

Abstract Bolted joint and gasket designers currently calculate spiral wound gasket stress in one of three ways. The differences lie in gasket area determination. The first is the historical Boiler & Pressure Vessel Code calculation method of using an effective sealing width which is half or less of the full dimensional width. Found to be inadequate for creating consistently acceptable sealing performance, those promoting and affecting lower leaks rates and emissions opt to use a gasket’s full width to determine gasket area and stress. The full width of a spiral wound gasket is currently being determined in two different ways among industry participants. Most use the dimensioned outer diameter which includes the bead of winding wire that does not contact the flange surface. Some exclude the width of the bead. Inclusion or exclusion of the bead has a significant impact on gasket seating stress for sealing elements of narrow width as the width of the bead represents a large percentage of the overall dimensions. In this paper, all three methods will be discussed focusing on gasket stresses for NPS calculated from the preferred method of full width comparing the inclusion and exclusion of the bead width.

Effects of Nut Thinning due to Corrosion on the Strength Characteristics and the Sealing Performance of Bolted Flange Joints Under Internal Pressure

2011 ◽  
Author(s):  
Tsutomu Kikuchi ◽  
Yuya Omiya ◽  
Toshiyuki Sawa
Keyword(s):  
Internal Pressure ◽  
Yield Stress ◽  
Strength Characteristic ◽  
Small Scale ◽  
Screw Thread ◽  
Flange Joint ◽  
Bearing Surface ◽  
Sealing Performance ◽  
Bolted Flange ◽  
Screw Threads

The effects of nut thinning due to corrosion on the strength characteristic and the sealing performance in 3B bolted flange joints under internal pressure are examined from both FEM calculations and experiments. The following results are obtained. When bolts and nuts in a bolted flange joint are tightened with 50% of yield stress, no yield region at the engaged screw thread occurs, however, when they arc tightened with 90% of the yield stress, a small scale yield region occurs at the roots of the engaged three screw threads from the bearing surface of the nut. While verifying this phenomenon using FEM, it was newly discovered that when the height of the nut was reduced to 1/3 (equivalent to approximately two threads) of the original dimensions according to the standards, the sealing performance could no longer be assured.

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.

Characterization of Sealing Behavior of Gaskets for the Leak Rate Based Design of Gasketed Bolted Flanged Connections

2008 ◽  
Author(s):  
Takashi Kobayashi
Keyword(s):  
Internal Pressure ◽  
Testing Procedure ◽  
Test Method ◽  
Leak Rate ◽  
Test Results ◽  
Japanese Industrial Standard ◽  
Sealing Performance ◽  
Stress Levels ◽  
Spiral Wound

This paper discusses the sealing behavior of gaskets according to the gasket testing procedure HPIS Z104 established in Japan. The testing procedure consists of eleven gasket stress levels while the internal pressure is constant. It takes about 3 hours to complete one test, which is acceptable for gasket manufacturers. The test method is going to be effective as the Japanese Industrial Standard (JIS) soon. Several sheet gaskets and spiral wound gaskets were tested based on the test method HPIS Z104 and test results are compared and discussed in this paper. Based on the test results, experimental formulas are proposed to approximate the sealing behavior of gaskets. It is shown that the sealing behavior of gaskets can be well characterized using the proposed testing procedure and the experimental formulas. The formulas have the possibility of application to the design of gasketed bolted flanged connections. It is also shown that the sealing performance of spiral wound gaskets with graphite and PTFE fillers is as good as that of sheet gaskets under an equal gasket load.

Improvement of Flange Tightening Method for Small Bore Low Rating Bolted Flanges

2010 ◽  
Author(s):  
Masako Mori ◽  
Akira Nebu ◽  
Takashi Kanno
Keyword(s):  
Axial Force ◽  
The Other ◽  
Test Results ◽  
Other Hand ◽  
Sealing Performance ◽  
Bolted Flange ◽  
Seating Surface ◽  
Spiral Wound

An appropriate flange tightening methods for small bore and low rating piping flange joints are clarified to improve the sealing performance of the bolted flange joints and the workability of flange tightening work. It is said that lubricant on the screw of the bolts and the nut-seating surface can minimize the variability of axial force acting on flange bolts, while this process might make it harder to tight the bolts uniformly especially for small bore low rating flanges. So, in this paper the appropriate condition to apply lubricant is clarified by a series of bolt tightening tests and sealing tests results. On the other hand, for the bolted flanges applying spiral wound gaskets, measuring the gasket compress dimensions help us to prevent uneven tightening balance and to perform the appropriate tightening work. Appropriate gasket compress dimensions are also clarified to ensure the sealing performance for the flanges based on the sealing tests results. Based on these test results, recommended flange-tightening methods have been summarized as an instruction and tightening work procedure to improve the sealing performance of the bolted flanges and the workability of flange tightening work.

Analysis of the Compression Behavior of Spiral Wound Gaskets

2009 ◽  
Author(s):  
A. Fitzgerald Jerry Waterland ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Pressure Vessel ◽  
Compression Behavior ◽  
Sealing Performance ◽  
And Performance ◽  
Flexible Graphite ◽  
Spiral Wound

Recent updates to the ASME B16.20 standard for spiral wound gaskets now require inner rings on all flexible graphite and PTFE filler spiral wound gaskets [1]. This new requirement is intended to prevent the occurrence of inward buckling; however the addition of an inner ring can have significant impact on the spiral wound gasket compression behavior and possibly its sealing performance. This paper explores the compression behavior and sealing performance of spiral wound gaskets, with and without inner rings, and thus provides a better understanding of their performance capabilities in ASME B16.5 flanges, as well as their design and performance within ASME Boiler & Pressure Vessel Code Appendix 2 flanges [2].

Sealing Performance Evaluation for Bolted Flange Joint with Spiral Wound Gasket Based on the Bolt Force

2019 ◽  
Vol 795 ◽  
pp. 246-253
Author(s):  
Fa Kun Zhuang ◽  
Xiao Peng Li ◽  
Guo Shan Xie ◽  
Jin Shi ◽  
Yian Wang
Keyword(s):  
Performance Evaluation ◽  
Internal Pressure ◽  
Chemical Plant ◽  
Leakage Rate ◽  
Flange Joint ◽  
Rate Model ◽  
Rate Parameter ◽  
Sealing Performance ◽  
Bolted Flange ◽  
The Relationship

Leakage accidents often occur at the bolted flange joints, which are widely used in the petro-chemical plant. This is mainly resulted by the reduction of bolt force during operation. Therefore, bolt force is very important for sealing performance of the joints in service. Based on the leakage rate parameter, the relationship between the bolt force and gasket stress was derived. Moreover, the leakage rate model was established on the basis of bolt force. With this model, the leakage rate can be directly calculated through the bolt force, and the sealing performance can be evaluated. In order to verify this model, corresponding experiments have been performed. It shows that with the internal pressure increasing, the bolt force increases and the gasket stress reduces. There exists a monotonic relationship between the bolt force and gasket stress. The theoretical gasket stress value corresponds well with the experimental value. The calculated leakage rates for the joints also agree well with the experimental value. Then, it is feasible to evaluate the sealing performance for the bolted flange joints based on the bolt force.

An Estimation of Long-Term Sealing Performance for Bolted Pipe Flange Connections With Spiral Wound Gaskets Under Elevated Temperature

2020 ◽  
Author(s):  
Koji Sato ◽  
Toshiyuki Sawa
Keyword(s):  
Elevated Temperature ◽  
Heat Conduction Problem ◽  
Estimation Method ◽  
Transient State ◽  
Sealing Performance ◽  
Nominal Size ◽  
Calculation Results ◽  
Flexible Graphite ◽  
Spiral Wound

Abstract SWGs (Spiral Wound Gaskets) are well known as a most used gasket type in bolted pipe flange connections all over the world. Recently, the connections with SWGs have been used under more severe conditions such as higher temperature and pressure, and in addition, the connections have been used in the more long-term application. Thus, it is necessary for plant owners (gasket users) to know the long-term characteristics of the connections with SWGs from a standpoint of integrity in the connections. In this study, the objective is to establish a long-term estimation method of sealing performance for bolted pipe flange connections with SWGs under elevated temperature. The long-term characteristics of pipe flange connections with SWGs are estimated using FEM calculations in which the fundamental mechanical characteristics of SWGs such as compression property under changed temperature is considered, thermal expansion behavior, creep relaxation and sealing performance are taken into considerations. For verification of FEM calculations, the experiments are carried out for the pipe flange connections with SWGs of which the nominal size is ASME class 300 2inch under elevated temperature and internal pressure. The gasket used is chosen as SWG with flexible graphite filler. The change in axial bolt forces and an amount of leakage are measured and the measured results are fairly coincided with the FEM calculation results. In addition, the contact gasket stress in the connection with SWG is shown in 72 months. The FEM calculations are performed as heat conduction problem in transient state.

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