The Metal Ring Seal is a kind of stainless steel hollow sealing ring, which is made by various precision processing and coated with different special material, which can meet the different application conditions . What is the metal ring seal? What is the sealing mechnism of the metal ring seal? Let’s take a look together.

Introduction of Metal Ring Seal

The metal seal ring is made of hollow seamless tubes. Its materials can be stainless steel, copper, aluminum, titanium and other alloys after precision machining, special welding, precision grinding, grinding and polishing. Different metal materials can be selected according to different use environment conditions, the outer surface of the metal seal ring can be coated with nickel, chromium, gold, silver and polytetrafluoroethylene. So metal seal ring can meet the needs of applications under different environmental conditions.

The metal seal ring is suitable for the sealed object without relative motion, which is also called static sealing. The seal ring can be made into circular, elliptical, rectangular and other geometric shapes according to specific usage requirements.

The sealing mechanism of the metal seal ring is similar to that of the sealing gasket. It also has the resilience generated by the deformation of the pre-tightened ring. The sealing contact surface of the ring produces contact stress. The contact stress causes the yield deformation of the ring surface to supplement the unevenness of the sealing surface to achieve the sealing requirements. The metal sealing hollow ring is a hollow tube, and the sealing contact surface is very small (compared with the sealing gasket), so the required sealing pre-tightening force is much smaller than the sealing gasket.

When in use, the metal seal ring should be installed in the matching installation groove, and the depth of the installation groove is slightly smaller than the pipe diameter of the seal ring to ensure that the seal ring has the required deformation for sealing after pre-tensioning. When the pressure of the sealed medium is higher than the atmospheric pressure, It should be positioned on the outer circle of the ring, and the outer circle of the ring should match the outer circle of the corresponding groove. When the pressure of the sealed medium is lower than atmospheric pressure (vacuum), it should be positioned on the inner circle of the ring, and the inner circle of the ring should match the inner circle of the corresponding groove.

Analysis of The Mechnism of Metal Ring Seal

After the sealing ring is installed in the sealing groove, its cross section undergoes contact compression stress and deforms. A predetermined initial contact pressure Po is generated on the contact surface. Even if there is no medium pressure or the pressure is very small, the O-shaped sealing ring can achieve sealing by its own elastic force. When the pressure medium is filled in the cavity, it will be under the action of the medium pressure. The O-shaped sealing ring is displaced and moved to the low pressure side, and its elastic deformation is further increased, filling and closing the gap.

At this time, the contact pressure of the coupling surface used for the sealing pair rises to Pm. Pm=Pa Pp. Once the contact pressure (0.1MPa) transmitted to the contact surface through the O-ring Pp=KPK-pressure transmission coefficient. For rubber O-ring K=1, P is the pressure of the sealed liquid (0.1MPa).

Thereby greatly increasing the sealing effect. Due to the general K21, so Pm>P. It can be seen that as long as there is an initial pressure on the O-ring, an absolute seal without leakage can be achieved. This property of changing the contact state of the O-ring seal by the pressure of the medium itself to achieve sealing is called self-sealing.

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By Johnny from Sonkit Industry

Email: johnny@sonkit.cn