Effect of Gasket Compression Resilience on the Tightness of Bolted Flange System

2016 ◽  
Vol 853 ◽  
pp. 328-334
Author(s):  
Xiao Tao Zheng ◽  
Jia Lin Zi Pan ◽  
Jiu Yang Yu
Keyword(s):  
Room Temperature ◽  
Design Calculation ◽  
Compression Force ◽  
Working Pressure ◽  
Flange Connection ◽  
Connection System ◽  
Gasket Material ◽  
Bolted Flange ◽  
Nonlinear Performance ◽  
Flange Angle

Gasket is an important sealing element of bolted flange connection structure. The nonlinear performance of the gasket material will make the flange angle and gasket compression force change. Therefore, it plays an important role in the tightness of bolted flange connection system. Apart from acknowledgment of this effect, there exists no established design calculation procedure that accounts for tightness. In this paper, the mechanical properties of the gasket at room temperature were studied, it is known that the rebound performance of the gasket is related to the initial preload. And the effect of the compressive resilience of the gasket on the tightness of the bolt flange system was discussed. The tightness of the bolt flange system can be achieved by adjusting the initial preload and working pressure of the gasket, it provides the basis for design and evaluate the tightness of bolted flange connection system.

Three-Dimensional Numerical Analysis for Bolted Flange Joints Considering Effect of Creep

2018 ◽  
Author(s):  
Lewen Bi ◽  
Lanzhu Zhang
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Numerical Analysis ◽  
Yield Strength ◽  
Room Temperature ◽  
Three Dimensional ◽  
Short Term ◽  
Flange Connection ◽  
Petroleum Chemical ◽  
Bolted Flange

Bolted flange joints are widely used in petroleum, chemical, nuclear and power industries, etc. With more and more devices are used at high temperature, the performance of flange connections becomes more complex, especially with creep of different components in flange connection. At elevated temperature, with the loss of bolt force and gasket force due to creep, the joints are prone to leak. Based on this, this paper analyzed the relaxation of bolt force at elevated temperature due to creep of bolt, flange and gasket separately and simultaneously. Besides, the influence of different initial installation stress of bolts was also studied. The results showed bolted flange joints relaxed due to gasket creep during early short term service. However, contribution of bolt and flange creep became more and more significant with the extension of time. With considering the creep of bolt, flange and gasket simultaneously, 50% to 60% of the bolt material yield strength at room temperature was recommended as the bolt initial installation stress for the joint case studied in this paper.

Analytical Modeling of the Contact Stress With Nonlinear Gaskets

2001 ◽  
Vol 124 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Michel Derenne
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Room Temperature ◽  
Analytical Modeling ◽  
Design Rules ◽  
Nonlinear Mechanical ◽  
Leak Tightness ◽  
Gasket Material ◽  
Bolted Flange ◽  
Contact Stress Distribution

Gasket contact stress and its variation through the gasket width is caused by the rotation of the flange and has an influence on the leakage tightness behavior of bolted flange joints. The future implementation by the ASME of proposed design rules is based on new gasket constants obtained from the ROTT (room temperature tightness) tests conducted on rigid platens. The gasket contact stress distribution needs to be addressed for the purpose of better joint tightness predictions. This paper presents a comprehensive analytical method that predicts the gasket contact stress distribution taking into account the nonlinear mechanical behavior of the gasket material. Based on the flange rotational flexibility, the proposed analytical model that is implemented in the “SuperFlange” program is supported and validated by numerical FEA and experimental analyses on flange rotations, radial distribution of gasket contact stress, and joint leak tightness.

Creep Modeling in Bolted Flange Joints

2004 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Akli Nechache
Keyword(s):  
High Temperatures ◽  
Contact Stress ◽  
Analytical Method ◽  
Calculation Procedure ◽  
Design Calculation ◽  
Bolted Joint ◽  
Load Relaxation ◽  
Gasket Material ◽  
Bolted Flange

Bolted flanged connections are used extensively in the petrochemical and nuclear industries. Under high temperatures, their leakage tightness behavior is compromised due to the loss of load as a result of creep of not only the gasket material but also the bolt and the flange materials. The relaxation of the bolt load and the corresponding loss of the gasket contact stress are not easy to assess analytically and consequently there is no established design calculation procedure. The objective of this paper is to present an analytical method that is part of the SuperFlange program [1] and is capable of predicting the load relaxation in a bolted joint when subjected to flange, bolt and gasket creep. The proposed method is validated by comparison with 3D FE models of different size flanges. In some cases, the relaxation caused by the flange and bolt materials is shown to be significant.

The Analysis of Bolted Flange Joints under Internal Pressure at High Temperature

2016 ◽  
Vol 853 ◽  
pp. 335-340
Author(s):  
Xiao Tao Zheng ◽  
Yang Cheng ◽  
Jiu Yang Yu
Keyword(s):  
Internal Pressure ◽  
Operation Time ◽  
Security Level ◽  
Creep Equation ◽  
Flange Connection ◽  
Bolt Preload ◽  
Connection System ◽  
Bolted Flange ◽  
Relationship Of ◽  
Unloading Deformation

Working temperature, internal pressure and the creep of bolted flange joints are the direct factors that influencing the gasket stress of bolted flange joints, the tightness of the whole system will be reduced because of these factors. thus the security level of bolted flange connection will be affected. In this paper, the deformation coordination equation of bolted flange connection system, the gasket compressive and resilient performance, as well as the gasket creep equation are combined to study the effect of internal pressure on bolted flange connections under a certain bolt preload and operating temperature, the equation about the relationship of the gasket force and internal pressure is simplified, and the main objective of the work is the calculation of the time-correlated gasket force, flange rotation and gasket unloading deformation under the different internal pressure. The results show that when the internal pressure is greater, the gasket force is smaller, on the contrary, the leakage rate are greater. Through the relevant conditions, in a period of the safe operation time, the maximum working internal pressure is got when reaching the condition of corresponding level of tightness.

Multi-Component ZnO-In2O3-SnO2Thin Films Deposited by RF Magnetron Co-Sputtering

2007 ◽  
Vol 124-126 ◽  
pp. 119-122 ◽  
Author(s):  
Chang Sik Son ◽  
Jae Sung Hur ◽  
Byoung Hoon Lee ◽  
Sang Yul Back ◽  
Jeong Seop Lee ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Visible Range ◽  
Rf Power ◽  
Working Pressure ◽  
Average Transmittance ◽  
Sno2 Thin Films ◽  
Ar Gas ◽  
Sputtering System ◽  
High Chemical Stability

Multi-component ZnO-In2O3-SnO2 thin films have been prepared by RF magnetron co-sputtering using targets composed of In4Sn3O12(99.99%) [1] and ZnO(99.99%) at room temperature. In4Sn3O12 contains less In than commercial ITO, so that it lowers cost. Working pressure was held at 3 mtorr flowing Ar gas 20 sccm and sputtering time was 30 min. RF power ratio [RF1 / ( RF1 + RF2 )] of two guns in sputtering system was varied from 0 to 1. Each RF power was varied 0~100W respectively. The thicknesses of the films were 350~650nm. The composition concentrations of the each film were measured with EPMA and AES. The low resistivity of 1-2 × 10-3 and an average transmittance above 80% in the visible range were attained for the films over a range of δ (0.3 ≤ δ ≤ 0.5). The films also showed a high chemical stability with time and a good uniformity.

Correlation on Scatter Between Torque Coefficient and Bolt Preload in Pipe Flange Connection

2016 ◽  
Author(s):  
Yuya Omiya ◽  
Masahiro Fujii
Keyword(s):  
Control Method ◽  
Torque Control ◽  
Flange Connection ◽  
Bolt Preload ◽  
Torque Coefficient ◽  
Gasket Material

In this paper, a mechanism of variation in axial bolt force in pipe flange connection during bolt tightening process is investigated. Especially, Correlation between torque coefficient and bolt preload is investigated. The actual pipe flange connection is tightened by a wrench due to the torque control method. Axial bolt forces were measured in the tightening process. The three types of gasket are chosen in this paper. As a result the good relationships are seen between torque coefficient and axial bolt force. The effect of gasket material on the relationships between torque coefficient and bolt preload is not seen.

Bolted Flange Joint Made of Glass Fibre Reinforced Polymer (GFRP) for Oil and Gas Pipelines

2018 ◽  
Author(s):  
Muhsin Aljuboury ◽  
Md Jahir Rizvi ◽  
Stephen Grove ◽  
Richard Cullen
Keyword(s):  
Glass Fibre ◽  
Oil And Gas ◽  
High Strength ◽  
Flange Joint ◽  
Element Analysis ◽  
Glass Fibre Reinforced Polymer ◽  
Linear Behaviour ◽  
Glass Fibre Reinforced ◽  
Gasket Material ◽  
Bolted Flange

The objective of this work is an experimental and numerical investigation for a bol Richard Cullen ted composite flange connection for composite pipes, which are used in the oil and gas applications, and obtain a joint with high strength and high corrosion resistance. For the experimental part, we have designed and manufactured the required mould, which ensures the quality of the composite materials and controls its surface grade. Based on the ASME Boiler and Pressure Vessel Code, Section X, this GFRP flange has been fabricated using biaxial glass fibre braid and polyester resin in a vacuum infusion process. Numerically, an investigation is carried out using 3D finite element analysis (FEA) of a bolted GFRP flange joint including flange, pipe, gasket and bolts. This model has taken into account the orthotropy of the GFRP material and the non-linear behaviour of the rubber gasket material for both the loading and non-loading conditions. Furthermore, the leakage propagation between the flange and the gasket has also been simulated in this investigation by using the pressure-penetration criteria PPNC in ANSYS. Finally, the flange has been tested under the internal pressure and the agreement between the experimental and numerical results is excellent.

Investigation on Different Tightening Sequences on Several Bolted Flange Types, Dimensions and Their Associated Gasket Types

2011 ◽  
Author(s):  
Hubert Lejeune ◽  
Yves Birembaut ◽  
Alexander Riedl ◽  
Arne Schunemann
Keyword(s):  
Quality Factor ◽  
Type A ◽  
Strain Gauges ◽  
Flange Connection ◽  
Elapsed Time ◽  
Torque Wrench ◽  
The Us ◽  
Bolted Flange

In the last years, several projects have been performed on alternative tightening sequences in the US and in Japan. This work has led to the publication of documents introducing alternative tightening procedures as JIS B 2251:2008 / HPIS Z 103 TR (JAPAN) and the new revision of ASME PCC-1:2010. In this study, the required bolt torque is calculated according EN1591-1 [1] (EN standard for bolted flange calculation according to a given tightness class) to achieve a given tightness class for each investigated gasket (6 types) and flange type (CLASS/PN)/dimension (from 4″/DN100 to 16″/DN400). The calculated bolt torque is then applied using a hydraulic torque wrench following three tightening sequences based on Legacy cross-pattern of ASME PCC-1:2010, alternative pattern #1 of ASME PCC-1:2010 and HPIS Z 103 TR. The bolted flange connection is then pressurized with Helium. The load for each bolt is continuously monitored using strain gauges, through the bolt-up phase and during pressurization. The average obtained bolt load, the bolt load scatter, the evolution of bolt load versus passes and elapsed time are compared for all the tested configurations (tightening sequence/ bolted flange type & dimension/ gasket type). A “Quality factor” is defined enabling comparison between the tightening quality (according to several criteria) of the different investigated tightening sequences in the tested configurations.

Effects of Post-Tightening on the Residual Bolt Force and the Sealing Performance of Flanged Connections With PTFE Gaskets (Long Term Effects at Room Temperature)

2011 ◽  
Author(s):  
Taiki Hagiri ◽  
Takashi Kobayashi ◽  
Kengou Nishiura ◽  
Kazuaki Uchiyama
Keyword(s):  
Room Temperature ◽  
Test Results ◽  
Long Term Effects ◽  
Viscoelastic Characteristic ◽  
Sealing Performance ◽  
Nominal Size ◽  
Gasket Material

It is known that bolt forces reduce significantly after tightening bolted flanged connections in which expanded PTFE gaskets are used. Bolts are often post-tightened in practice after a while to compensate for the reduction of bolt forces. The viscoelastic characteristic of expanded PTFE gaskets is the main cause for the phenomenon. However, the long term effects of the post-tightening on the residual bolt forces and the sealing performance of flanged connections have not been clarified yet. In this study, two sets of flanged connections (2 inch in nominal size), in which PTFE gaskets were used, were prepared and tightened. One of the flanges was post-tightened after a designated time. The reduction of bolt forces and the change in the sealing performance were measured for about two months. The results were compared with those of flanges without post-tightening. Based on the test results, the effectiveness of post-tightening was discussed from the viewpoint of the residual bolt force and the sealing performance. It has been clarified that the effectiveness of post-tightening depends on gasket material and that post-tightening is effective for expanded PTFE gaskets.

Reduction of Fugitive Emissions From Bolted Flanged Connections by Using PTFE Blended Gasket

2016 ◽  
Author(s):  
Takashi Kobayashi ◽  
Koji Sato ◽  
Akira Muramatsu ◽  
Toshiyuki Sawa
Keyword(s):  
Heat Resistance ◽  
Pressure Vessel ◽  
Room Temperature ◽  
Research Council ◽  
Estimation Method ◽  
Leak Rate ◽  
Fugitive Emissions ◽  
Flange Connection ◽  
Sealing Performance ◽  
Creep Characteristic

Gasket is the key element which determines the tightness of bolted flanged connection. PTFE blended gaskets which have recently been developed and come onto the market have a superior sealing performance as well as the chemical and temperature resistances and can contribute to reduce fugitive emissions. This paper deals with the sealing behaviors of the PTFE blended gasket and the tightness of a bolted flanged connection in which the gasket is used. The gasket is mainly composed of PTFE and graphite and has a high tightness and heat resistance up to 300 degree C. The creep characteristic is improved by the graphite filler. In this paper, the estimation method of the tightness of bolted flanged connections based on the sealing behavior of gasket is demonstrated. The estimated results are validated by experiments using a flange connection. It is shown that the leak rate below the tightness class 4 defined in the Room Temperature Tightness Test (ROTT, Pressure Vessel Research Council) can be obtained using the PTFE blended gasket.

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