The hydraulic main pump is a kind of fluid pump. About the fluid sealing, it usually uses the mechanical seal to contain the fluid within a vessel (typically pumps, mixers, etc.) where a rotating shaft passes through a stationary housing or occasionally, where the housing rotates around the shaft.

Mechanical seals are usually fixed at the point of entry or exit of a rotating shaft. Typically it is used to prevent the leakage of one high-pressure fluid into a lower pressure fluid.

* Seal kits are made of specialized materials for the maximizing durability with wear resistance, properly heat treated body to produce optimum performance of the machine and life time seal and lubriion which were thoroughly checked by standard rule on each seal kit in order to ensure a perfect sealing. Thus, the perfect oil sealed lubriion is assured of life time service operation in terms of retaining the oil lubricant for the perfect operation between piston and cylinder.