Mechanical seal refers to a device for preventing fluid leakage caused by at least one pair of end faces perpendicular to the rotation axis under the action of the fluid pressure and the compensating mechanism elastic force (or magnetic force) and the auxiliary seal. .

The elastic loading mechanism and the auxiliary seal are the mechanical seals of the metallic tube. We call it the metal bellows seal. In the light seal, there is also a rubber bellows for auxiliary sealing. The rubber bellows has limited elastic force, and generally needs to be supplemented with a spring to satisfy the loading elasticity. "Mechanical seals" are often referred to simply as "machine seals."

Mechanical seals are shaft seals for rotating machinery. Such as centrifugal pumps, centrifuges, reactors and compressors. Since the drive shaft runs through the inside and outside of the device, there is a circumferential gap between the shaft and the device, and the medium in the device leaks outward through the gap. If the pressure inside the device is lower than atmospheric pressure, the air leaks into the device, so there must be a A shaft seal that prevents leakage. There are many types of shaft seals. Because mechanical seals have the advantages of less leakage and long life, the world's mechanical seals are the most important shaft seals in these equipments. Mechanical seals, also known as end seals, are defined in the relevant national standards: "The at least one pair of end faces perpendicular to the axis of rotation are held together by the action of the fluid pressure and the compensating mechanism's spring force (or magnetic force) and the auxiliary seal. a device that prevents fluid leakage by sliding relative to each other."

1, the main components

Moving ring, static ring, cooling device and compression spring (depending on the specific equipment).

2, auxiliary seals

Sealing ring (O-shaped, X-shaped, U-shaped, wedge-shaped, rectangular flexible graphite, PTFE coated rubber O-ring, etc.).

3. Elastic compensation mechanism

Spring, push ring.

Spring seat and key or various screws.

Classification of mechanical seals:

Divided into single end, double end; balanced, unbalanced; any direction of rotation, fixed rotation.