The popularity of high-pressure water cleaning equipment has led to even more exacting demands being made on seals fitted to the water pump. For example, seals often have to operate in hot water, with high pressures on the pumping stroke and vacuum on the suction stroke. In the early cleaning equipment, the seals originated from oil hydraulic
components.

Oil seals were often used for sealing the gearbox. With these seals, it was impossible to meet the exacting demands of the suction stroke and the hot water. These seals also had a short service life. Damage to the pump motor was a common failure. It was caused by water passing the seal and entering the lubricating oil. Another common failure was damage to the surface of the plunger because the seals were too tight. Overcoming these problems led us to develop a new sealing system where the seals are carefully designed for the water and gearbox oil to ensure long service life. Our Parker Prädifa system uses three profiles W1, W2, and W7. It has features that overcome the earlier problems.

A special profile front ring for the suction operation. An additional lip on the gearbox seal preventing damage by water penetration. No pump failure through sticking or damaged plungers. The seal system design incorporates features based on value analysis which results in a sealing concept that can withstand extreme pressure variations, high temperatures, and minimal lubrication. High-pressure cleaning equipment incorporating these seals will meet the most exacting demands of the user.

Field of application

Working pressure:               ≤ 80 bar

Working temperature:        up to +80 ºC

Surface speed:                       ≤ 2 m/s

Installation:

The Parker Praedifa profile W2 is installed into an axial open groove usually with the aid of an insertion cone and a matched ring. The seal profiles are larger than the recess so insertion is easier if a small amount of a  suitable grease is smeared over the seal.

Compounds:

U-seal:                NBR rubberized fabric

(05018/05023).

Header ring:      Polyacetal (W5001

For special requirements (pressure, temperature, speed, etc.) please contact Service, so that suitable material can be recommended.