Sealing Performance Evaluation of Pipe Flange Connection With Spiral Wound Gasket Under Cyclic Thermal Condition

2009 ◽  
Author(s):  
Yoshio Takagi ◽  
Hiroyasu Torii ◽  
Toshiyuki Sawa ◽  
Yuya Omiya
Keyword(s):  
Thermal Expansion ◽  
Elevated Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Compression Tests ◽  
Flange Connection ◽  
Leakage Test ◽  
Sealing Performance ◽  
Spiral Wound

Although a lot of pipe flange connections are exposed to elevated temperature during long-term plant operation, a sealing performance of the pipe flange connections at elevated temperature is not well understood because of the experimental difficulty and the analytical problems which result from the lack of the materials properties of gaskets at elevated temperature. The authors have been evaluating the effects of the material properties of spiral wound gaskets (SWG) and the sealing performance of the pipe flange connections at elevated temperature with numerical and experimental analysis. The gasket stress induced by the mismatch of the thermal expansion between the gasket and flange/bolt increased as increasing the temperature in the case that the thermal expansion coefficient of the gasket was larger than that of bolt/flange material and the sealing performance of the pipe flange connection was improved. However, the thermal expansion coefficient declines at temperatures higher than 210 °C. In addition, the binder compositions of SWG vaporize and the mechanical properties slightly change at high temperature such as higher than 200°C. Therefore, the sealing performance of pipe flange connection with SWG might decline more than 200°C. The sealing performance and long-term durability of pipe flange connection with SWG at elevated temperature were evaluated in this study. The long term leakage test with heat cycle revealed that the sealing performance of pipe flange connection didn’t show any degradation for 21 days. The compression tests for the new, the thermal aged and the used gaskets were done to investigate the effect of material characteristics on the long term sealing performance. In addition to the leakage test and the compression tests, the thermal characteristics of SWG were evaluated by the Thermogravimetry/Differential Thermal Analyzer (TG/DTA) measurement. The measurement showed the weight loss of SWG more than 130°C. According to those experimental results and FE analysis, the effect of temperature on the sealing performance was discussed.

Effect of Material Properties of Gasket on the Sealing Performance of Pipe Flange Connections at Elevated Temperature

2015 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yoshio Takagi ◽  
Hiroyasu Torii
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Elevated Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Material Properties ◽  
Compression Tests ◽  
Flange Connection ◽  
Sealing Performance ◽  
Spiral Wound

The sealing performance of the pipe flange connection depends on the compressive gasket stress. Therefore, the unexpected leakage can be avoided by estimating the change in compressive gasket stress during operation. In order to make such estimation, the material properties of the gasket are required as well as those of bolt and flange material. When the pipe flange connection is used under heated condition, the thermal expansion coefficient shows an important role. For example, if the thermal expansion coefficient of gasket is larger than that of pipe flange material, the gasket stress is expected to be increased by increasing the temperature and the sealing performance of pipe flange connection is improved. However, a gasket tends to be softening at high temperature. Beside, the creep phenomenon of gasket induces the decrease of gasket stress. Thus, the behavior of the gasket is complicated and it should be investigated to make a reliable design. In this paper, the high temperature properties, including thermal expansion and stress relaxation property of spiral wound gasket with expanded graphite are examined by compression tests at elevated temperature. The stress analysis with high temperature material properties obtained from the compression tests also conducted to estimate the sealing performance of pipe flange connection. As a result, the pipe flange connection with spiral wound gasket is expected to keep the superior sealing performance at 300 C for long time.

Stress Analysis and Sealing Performance Evaluation of Pipe Flange Connection at Elevated Temperature

2008 ◽  
Author(s):  
Yoshio Takagi ◽  
Hiroyasu Torii ◽  
Toshiyuki Sawa ◽  
Naoki Kawasaki
Keyword(s):  
Thermal Expansion ◽  
Elevated Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Material Properties ◽  
Strain Curve ◽  
Flange Connection ◽  
Sealing Performance ◽  
Higher Temperature ◽  
Experimental Difficulty

Although a lot of pipe flange connections are exposed to elevated temperature during plant operation, a sealing performance of the pipe flange connections at elevated temperature is not well understood because of the experimental difficulty and the analytical problems due to the lack of the materials properties of gaskets at elevated temperature. The authors have been evaluating the sealing performance of the pipe flange connections at elevated temperature with numerical and experimental analysis and showed the strong effect of the material properties of the gaskets, like a thermal expansion coefficient and a stress-strain curve, on the sealing performance. In order to make a further evaluation, the effect of material properties on the sealing performance was analyzed by using FEM. In the FE analysis, the material properties were varied to evaluate the effect of them on the sealing performance. Furthermore, the material properties and the mechanical characteristic of the gasket were evaluated as a function of temperature. The obtained properties were used to reanalyze the sealing performance of the pipe flange connection. As a result, the gasket stress induced by the mismatch of the thermal expansion between the gasket and flange/bolt increased as increasing the temperature in the case that the thermal expansion coefficient of the gasket was larger than that of bolt/flange material and the sealing performance of the pipe flange connection was improved. However, the improvement in the sealing performance at elevated temperature was not expected so much at higher temperature due to the less increment of the thermal expansion and thermal stress of the gasket. This paper discuss about the change in the sealing performance of the pipe flange connection under elevated temperature considering the material properties and mechanical characteristics of the gasket.

The Effect of the Thermal Expansion Coefficient on the Sealing Performance of Pipe Flange Connections With NiTi Shape Memory Alloy Gaskets

2006 ◽  
Author(s):  
Yoshio Takagi ◽  
Teruhisa Tatsuoka ◽  
Toshiyuki Sawa
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Research Council ◽  
Nickel Titanium ◽  
Niti Shape Memory Alloy ◽  
Ti Alloy ◽  
Sealing Performance

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to endure a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. The authors have paid attention to the super elasticity of the shape memory alloys like Nickel-Titanium (Ni-Ti) alloy and evaluated its applicability to a gasket. In the process, leakage tests of the flange connections with Ni-Ti alloy gaskets were done and the sealing performance was evaluated with the new gasket constants and the tightness parameter proposed by PVRC (Pressure Vessel Research Council, ASME). The results revealed that Ni-Ti alloy gaskets showed a superior sealing performance to the conventional aluminum gasket. However, the thermal expansion coefficient of Ni-Ti alloy is smaller than that of stainless steel of which the flange is made. The increase in temperature of the flange like 20 °C to 40 °C accordingly induced a slight degradation of the sealing performance. In this paper, the effect of the change in temperature on the sealing performance of the pipe flange connections with Ni-Ti alloy gasket was numerically evaluated with the measured thermal expansion coefficient. Moreover, the effect of the clamped temperature on the sealing performance was evaluated taking into account the temperature dependence of the mechanical properties of Ni-Ti alloy.

The Stress Analysis and the Sealing Performance Evaluation of the Pipe Flange Connection at Elevated Temperature

2010 ◽  
Author(s):  
Yoshio Takagi ◽  
Hiroyasu Torii ◽  
Toshiyuki Sawa ◽  
Yuya Omiya
Keyword(s):  
Thermal Expansion ◽  
Performance Evaluation ◽  
Elevated Temperature ◽  
Material Properties ◽  
Fe Analysis ◽  
Flange Connection ◽  
Leakage Test ◽  
Precise Evaluation ◽  
Sealing Performance ◽  
Diameter Pipe

The authors have been evaluating the effects of the material properties of spiral wound gaskets (SWG) and the sealing performance of the pipe flange connections at elevated temperature with numerical and experimental analysis. The contact gasket stress increased by the mismatch of the thermal expansion between the gasket and flange/bolt as increasing the temperature and the sealing performance of the pipe flange connection was improved. The authors have also evaluated the effect of scatter in axial bolt force and revealed the assembly efficiency is not as high as expected in case of large nominal diameter pipe flange connection. Following the previous studies, the sealing performance of pipe flange connection and the assembly efficiency with SWG at elevated temperature were further evaluated with the experimental leakage test and 3-D FE analysis in this study. In order to make a precise evaluation, the experimentally obtained material properties of SWG were used in the analysis. The uniform axial bolt force tests and the scattered axial bolt force test were done to compare the sealing performance and the assembly efficiency evaluated by the ratio of the tightness parameter of each test at elevated temperature. Although the leak rate improved as increasing the temperature, the assembly efficiency decreased. The leakage based assembly efficiency was proposed according to the experimental results and numerical analyses.

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.

scholarly journals Out-of-Plane Thermal Expansion Coefficient and Biaxial Young’s Modulus of Sputtered ITO Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 153
Author(s):  
Chuen-Lin Tien ◽  
Tsai-Wei Lin
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Young's Modulus ◽  
Heating Temperature ◽  
Glass Substrates ◽  
Ito Thin Films

This paper proposes a measuring apparatus and method for simultaneous determination of the thermal expansion coefficient and biaxial Young’s modulus of indium tin oxide (ITO) thin films. ITO thin films simultaneously coated on N-BK7 and S-TIM35 glass substrates were prepared by direct current (DC) magnetron sputtering deposition. The thermo-mechanical parameters of ITO thin films were investigated experimentally. Thermal stress in sputtered ITO films was evaluated by an improved Twyman–Green interferometer associated with wavelet transform at different temperatures. When the heating temperature increased from 30 °C to 100 °C, the tensile thermal stress of ITO thin films increased. The increase in substrate temperature led to the decrease of total residual stress deposited on two glass substrates. A linear relationship between the thermal stress and substrate heating temperature was found. The thermal expansion coefficient and biaxial Young’s modulus of the films were measured by the double substrate method. The results show that the out of plane thermal expansion coefficient and biaxial Young’s modulus of the ITO film were 5.81 × 10−6 °C−1 and 475 GPa.

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