Packing rings for pump piston - with constant friction to the cylinder lining

摘要

The piston has two end discs and an annular slot in the length between them. This slot is fitted with =1 sealing ring and =1 elastic support ring. When the sealing rings swell in service they press on to the elastic ring which has space enough to deform, thus preventing increased pressure on the cylinder lining. Similarly, if the sealing rings shrink by drying, the elastic ring expands on to them and ensures continued sealing efficiency.