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Mechanical Seal Skills Requirement

A mechanical seal means a means for preventing fluid leakage caused by at least one pair of end faces perpendicular to the axis of rotation which are retained and slid under the action of the fluid pressure and the resilient force (or magnetic force) of the compensating mechanism and the auxiliary seal.

The elastic loading mechanism with the auxiliary seal is the metal seal of the mechanical seal we call the metal bellows seal. In the light seal, there are rubber bellows for auxiliary sealing, rubber corrugated tube is limited, generally need to supplement the spring to meet the loading elastic. "Mechanical seal" is often referred to as "seal".

A mechanical seal is a shaft seal for a rotating machine. Such as centrifugal pumps, centrifuges, reactors and compressors. As the drive shaft penetrates inside and outside the equipment, there is a circumferential gap between the shaft and the device, and the media in the equipment leaks out through the gap. If the pressure in the equipment is below atmospheric pressure, the air leaks into the equipment, so there must be a A shaft seal that prevents leakage. Many types of shaft seals, because the mechanical seal with less leakage and long life, etc., so the world's mechanical seal is the most important shaft seal in these devices. The mechanical seal, also known as the end seal, is defined in the relevant national standard: "The end faces of at least one pair of faces perpendicular to the axis of rotation remain in contact with the action of the fluid pressure and the resilient (or magnetic) of the compensating mechanism and the auxiliary seal A device that prevents fluid leakage from moving relative to each other.

Summary of principles

Mechanical seal is a pair of pairs of vertical relative to the axis of the relative sliding end of the fluid pressure and compensation mechanism of the elastic (or magnetic) under the action of the paste and with an auxiliary seal to achieve leakage of the shaft seal device.

Commonly used mechanical seal structure consists of static ring (static ring), rotating ring (moving ring), elastic element spring seat, set screw, rotary ring auxiliary seal ring and static ring auxiliary sealing ring and other components, anti-pinning fixed To prevent the static ring from rotating.

The rotating rings and the stationary rings are also often referred to as compensating rings or non-compensating loops, depending on whether they have axial compensation capability.

Seal ring is the ring and the static ring of the general (the same below), is the main component of the mechanical seal. The seal ring determines the performance and life of the mechanical seal to a large extent, and therefore makes some demands on it.

Have sufficient strength and stiffness

Under working conditions (such as pressure, temperature and sliding speed, etc.) is not damaged, the deformation should be as small as possible, the working conditions can still maintain the sealing. Especially the sealing end to have sufficient strength and a certain degree of corrosion resistance to ensure that the product has a satisfactory service life.

Have good thermal shock resistance

To this end, the requirements of the material has a high thermal conductivity and a small linear expansion coefficient, to withstand thermal shock will not crack.

Small coefficient of friction

Seal ring matching should have a small coefficient of friction.

Good self-lubricating

Work in the event of a short period of dry friction, do not damage the sealed face. Therefore, the seal ring to have a good self-lubricating, sealing ring material and sealing fluid but also a very good wetting.

Simple structure

Seal ring structure should be a simple symmetry, give priority to the use of the overall structure, can also be used in combination (such as inlay) seal ring, try to avoid the use of sealed end-face spray structure.

Seal rings are easy to manufacture

Installation and maintenance to be convenient, the price should be low.