Hardware talks with you about the knowledge of custom metal sealing gaskets

Customized metal sealing gaskets occupy a very important position in modern industrial enterprises. The quality of the sealing is directly related to the continuity of production, energy saving and environmental protection, and people's physical and mental health. Therefore, the development of gaskets has attracted more and more attention. With the rise of modern industry, especially the modern petroleum, chemical industry, atomic energy industry, and large-scale power stations, pressure vessels are developing in the direction of high temperature, high pressure, high vacuum, cryogenic, large-scale and multi-series, and new requirements for gasket sealing are constantly being put forward. , A variety of new materials and new structures continue to appear, and their sealing performance is also very different. In addition, pressure fluctuations, temperature changes, bolt pre-tightening, flange inclination, misalignment, sealing surface defects, and medium corrosion will all have a great impact on the sealing effect. Therefore, how to correctly select the appropriate customized metal gasket according to the working conditions and how to install it correctly is the key to ensuring the sealing effect. Important factors affecting gasket selection Gasket selection is not an easy task, especially in the selection of gasket sealing materials, many factors must be considered. The variables that appear at the flange connection seem to be endless, and all these uncertain factors affect the sealing effect of the gasket. In the past, the parameters of 'TEMP' (temperature, application, medium, pressure) seemed to be sufficient. But today, the processing quality of the flange, the amount of bolt thread embedding, the amount of flange rotation, the amount of bolt tightening, the filler of the medium and the surface treatment of the flange, all affect the sealing effect of customized metal gaskets. Therefore, a comprehensive consideration of various parameters can make an appropriate choice. (Temperature) In most selection processes, the temperature of the fluid is the primary consideration. This will quickly narrow the selection, especially from 200°F (95°C) to 1000°F (540°C). When the operating temperature of the system reaches the limit of the high continuous operating temperature of a particular gasket material, a higher grade material should be selected. This should also be the case under certain low temperature conditions. (Application) The important parameters in the application are the type of flange and the bolts used. The size, number, and grade of bolts in the application determine the payload. The effective area to be compressed is calculated from the contact size of the gasket. The effective gasket sealing pressure can be derived from the load of the bolt and the contact surface of the gasket. Without this parameter, it would be impossible to make a choice among many materials. (Medium) There are thousands of fluids in the medium, and the corrosiveness, oxidation and permeability of various fluids vary greatly. Choose the material according to these characteristics when selecting the model. In addition, the cleaning of the system is also taken into consideration to prevent the erosion of the gasket by the cleaning fluid. (Pressure) Each type of gasket has its highest ultimate pressure. The pressure-bearing performance of the gasket decreases with the increase of the material thickness. The thinner the material, the greater the pressure-bearing capacity. The selection is based on the pressure of the fluid in the system. If the pressure fluctuates frequently, you need to know the details in order to make a choice. (PT value) The so-called PT value is the product of pressure (P) and temperature (T). The pressure resistance capacity of each gasket material is different at different temperatures, which is considered comprehensively. Under normal circumstances, the gasket manufacturer will give the maximum PT value of the material. Selection steps (to determine the standard used for gaskets) Generally, the standard used for gaskets is the same as that used for flanges. The commonly used standards are: China National Standard (GB), Machinery Industry Standard (JB/T), Chemical Industry Standard (HG), International Standard (ISO), etc. (Determine the nominal diameter and nominal pressure of the gasket) The nominal diameter and nominal pressure of the gasket are the same as those of the flange. Such as: DN100-PN2.5. (Determine the type of gasket) Determine the type of gasket used according to the nominal pressure and the high temperature of the medium. It is mainly divided into flexible graphite, polytetrafluoroethylene, rubber, non-asbestos fiber gaskets and spiral wound gaskets, wave live pressure gaskets, oval gaskets and octagonal gaskets. As asbestos gaskets are being phased out due to environmental protection and health reasons, it is not recommended in this article. (Determine the form of gaskets) The forms of gaskets are mainly divided into four categories: non-metallic soft gaskets, spiral wound gaskets, metal composite gaskets and metal gaskets. The specific gasket form should be selected according to the flange form and with reference to the technical parameters provided by each manufacturer. (Determine the material and model of the gasket) The material of the gasket should be determined according to the temperature, pressure, and corrosion properties of the medium, and then the type of the gasket should be determined according to the above content. The type of gasket generally includes six parts: gasket form, material, nominal diameter, nominal pressure, standard number, manufacturer or brand. The above is about the selection of custom metal gaskets. If you have other questions about gaskets, you can leave a message, and we will answer for you in a moment. Or call the hardware service hotline: