Sealing forms for chemical centrifugal pumps without leakage

The pursuit of leak free centrifugal pumps in chemical equipment has led to the increasing application of magnetic pumps and shielded pumps. However, there is still a long way to go to truly achieve no leakage, such as the lifespan issues of magnetic pump isolation sleeves and shielding pump shielding sleeves, material pitting issues, and reliability issues of static seals.

1. There are two types of sealing forms: static sealing and dynamic sealing.

For static sealing, only two sealing forms are usually used: sealing ring and sealing gasket, and O-ring is widely used in sealing rings; For dynamic seals, packing seals are rarely used, mainly mechanical seals, which are divided into single and double end faces, balanced and unbalanced types. Among them, the balanced type is more suitable for sealing high-pressure media, which usually refers to a pressure greater than 1.0MPA. The double end face machine seal is mainly used for high temperature, easy crystallization, viscous, particle containing, and toxic volatile media. The double end face machine seal should inject isolation liquid into the sealing chamber, and its pressure is generally 0.07-0.1MPA higher than the medium pressure.

2. Sealing material.

The material for static sealing of chemical pumps usually uses fluororubber material, and in special cases, polytetrafluoro material may be used; The material of mechanical sealing dynamic and static rings should be carefully selected, and not all should be made of hard alloy. If all hard alloys are chosen, the price will be very high.