O-ring seal three types of detailed explanation

The metal O-ring seal has excellent sealing performance, high temperature resistance, corrosion resistance and air tightness, and is especially suitable for high pressure and high vacuum sealing. It can be used as a sealing element with different diameters.
Metal O-rings have been commercialized abroad, and you can buy products with different materials, specifications and forms. The United States, Japan, Britain, and the United States have manufacturers and companies specializing in the production of such seals. At present, there are also metal O-rings of various specifications and different materials in China, and they are also made by manufacturers, and their performance is still good.

There are currently three types of metal O-rings (as shown): non-self-tightening, self-tightening, and inflatable.

Metal O-ring form

Non-self-tightening O-rings are suitable for use in fully constrained or semi-constrained designs to seal vacuum, low pressure and pipe seals with corrosive media.

Self-tight O-rings are only suitable for semi-constrained designs. There are many small holes drilled inside the ring. Due to the internal pressure of the same operating pressure in the tube, the self-tightening is increased. As long as the flange and the fastener have sufficient strength and rigidity, the infinitely high pressure can be sealed, and the pressure can be used. Up to 8500 atmospheres, sometimes even above 7,000 atmospheres, is the most structural form of this type of sealing pressure.

The inflatable O-ring is suitable for full-constrained or semi-constrained design. The tube is filled with inert gas. The pressure is generally 40~50 kg/cm2, which can be determined according to the application requirements. Although the strength of the pipe is lowered at high temperatures, the gas pressure is increased at the same time, which enhances the rebound ability and compensates for the sealing performance. Usually used for 400~800°C

The sealing mechanism of the metal O-ring is similar to that of the flat pad. The resilience generated by the deformation of the pre-tightening ring causes a certain stress on the sealing surface. This stress causes the surface material of the hollow ring to yield, fills the unevenness on the sealing groove, and compensates for the non-parallelism of the sealing surface to achieve the sealing. That is, the elasticity of the hollow ring tightly fits the sealing surface of the ring and the groove to achieve sealing. Therefore, in the main manufacturing process of the O-ring, the polished surface, the cutting, the bending, the pier, the butt welding, the grinding, the inspection, the polishing, the surface finish is required. When sealing active media, high ductility compensating materials should also be plated or sprayed. Of course, the flange face that matches the O-ring has the same requirements.

The choice of tubing for metal O-rings can be based on the physicochemical properties of the sealing medium, equipment operating pressure, temperature and load characteristics. The wall thickness is determined by the characteristics of the medium and the design pressure; the outer diameter of the tube is determined by the diameter of the 0-ring.