The octagonal pad is made of metal material by forging and heat treatment and mechanical processing into a solid metal gasket with a cross-sectional shape of octagonal shape. It has a radial self-tightening seal and is a standard R-type metal ring pad. Its principle of action is The gasket is in contact with the inner and outer surfaces (mainly the outer side surface) of the flanged trap groove, and is pressed to form a sealing action.
Chinese name octagonal mat material Carbon steel, stainless steel 304, 316, etc. Shaped octagonal, oval Applicable range -200-800 °C 2.0-42 MPa
Material: carbon steel, stainless steel 304, 316, etc.
Shape: octagonal, oval
Scope of application: Temperature: -200-800 ° C Pressure: 2.0-42 MPa
Suitable for: high temperature, high pressure pipe flange sealing.
The octagonal metal ring pad is installed in the ladder ring groove on the flange surface. When the connecting bolt is tightened, it is axially compressed and the upper and lower ladder grooves are tightly pressed to produce plastic deformation, forming an annular sealing band to establish an initial seal. After boosting, the ring pad is radially expanded by the pressure of the medium. The shims of the gasket and the trapezoidal groove are more tight and self-tightening. However, an increase in the pressure of the medium also causes the flange and the connecting bolt to deform, resulting in a relative separation between the sealing faces, and the gasket sealing ratio is relatively lowered. Therefore, the ring pad can be considered as a semi-self-tightening seal.
The octagonal metal ring pad is mainly in surface contact with the flange groove. Although it is not easy to be in close contact with the flange groove compared with the elliptical ring pad, it can be used again, and the cross section is made up of straight lines for easy processing. At the same time, the hardness of the octagonal metal ring pad should be lower than the flange surface of 15~20HB.
Octagonal metal ring pad performance characteristics:
1. High temperature resistance and high pressure resistance, suitable for high pressure flanges;
2, the seal is durable and reliable;
3. Adapt to the working conditions of pressure and temperature fluctuations;
Octagonal metal ring pad application range: usually used in high temperature and high pressure steam, gas, solvent pipe flange, tower tank, pressure vessel, high speed joint surface, high temperature and high pressure valve, cover. Wellhead device and seal on the tree in the oil and gas industry
The metal ring pad was originally from the United States. It was used in the boiler field in the early 1920s. It was later used for manhole cover and sealing of other windows of the autoclave. It was particularly valued in the petroleum production and refining industry. As the temperature and pressure of steam power plants increase, the use of metal ring mats is becoming more widespread.