聚四氟乙烯、 椭圆垫、 金属包垫、金属平垫，今天我们就来详细介绍一下这几种密封垫片。 The types of gaskets include industrial rubber plates, metal winding gaskets, polytetrafluoroethylene, oval gaskets, metal blankets, and metal flat gaskets. Today we will introduce these types of gaskets in detail.
工业橡胶板 First, industrial rubber sheet
The rubber sheet is used as a flange gasket, which is mostly used for pipes or manholes and hand holes that are frequently disassembled, and the pressure does not exceed 1.568MPa. Among the various types of gaskets, the rubber gasket is the softest and has a good bonding performance, and the sealing effect can be exerted under a small pre-tightening force. Because of this, when the internal pressure is applied, the gasket is easily extruded due to the thicker or lower hardness of the gasket. The rubber sheet is used in organic solvents such as benzene, ketone, ether, etc., which is prone to swelling, weight gain, softening, and stickiness, resulting in seal failure. Generally cannot be used if the swelling degree exceeds 30%.
Under low pressure and vacuum conditions, rubber pads are more suitable. The rubber material has good compactness and low air permeability. For example, fluoro rubber is the most suitable sealing gasket for vacuum containers, and the vacuum degree can reach 1.3 × 10-7Pa. When the rubber pad is used in the vacuum range of 10-1 ~ 10-7Pa, it needs to be baked and exhausted.
Second, metal winding pads
Metal winding pads cleverly use the heat resistance, resilience and strength of metals and the softness of non-metallic materials, so the sealing performance is better, and the performance of winding flexible graphite pads with stainless steel tape is the best. Its pre-tightening ratio is smaller than that of asbestos winding pads, and there is no shortcoming of leakage of asbestos fiber pores.
Teflon has a low coefficient of friction, and the gasket is easy to slide outwards when pre-tensioned, so it is best to use a concave and convex flange surface. When a flat flange is used, the outer diameter of the gasket can contact the bolt, and the bolt can be used to prevent the gasket from slipping outside. Because the glass-lined equipment is sintered after spraying a layer of enamel on the metal surface, the glaze layer is very brittle, coupled with uneven spraying and flow of the glaze layer, the flange surface is flat. The metal composite gasket is easy to damage the glaze layer, so it is recommended to use a polytetrafluoroethylene blanket with a core material made of asbestos sheet and rubber. This kind of cushion is easy to fit on the flange surface and is resistant to corrosion.
Fourth, the metal pad
The advantages of metal cladding are high strength, non-fragile, strong and strong, but the rebound force is limited. The flange surface needs to be flat and the fastening force is high to achieve good results. According to different materials, it can be combined into 201, 304, 316 stainless steel coated graphite (temperature-resistant 650 degrees) coated pads, asbestos coated pads, ceramic fiber coated pads and other forms.
Material: Q235A, stainless steel, copper, aluminum, etc.
Filling material: flexible graphite, asbestos, non-asbestos, ceramic fiber (10%), etc.
Uses: Suitable for sealing flanges of pressure vessels with larger diameters. Seals for pumps, pipes, valves, pipes and flanges of various equipment.
Five, metal flat pad
Generally used for medium and high pressure valves, pipes and smaller diameter equipment flanges. The use pressure is 1.568 ~ 31.36MPa and the latter is 1.568 ~ 3.92MPa according to the temperature. The gasket material is selected according to the medium and temperature.