Water jet rock breaking cannon - has lubricating and sealing arrangement with stepped piston inside stepped cylinder

摘要

The lubricating and sealing assembly is used on a water jet gun producing a narrow high pressure jet for rock working. The gun (2) has a high pressure cylinder (4) with a stepped inner surface (6) in which operates the floating plunger designed as a differential piston. The larger part (10) of the plunger is adjacent to the gas space (12) and the smaller central plunger part (14) is next to the fluid chamber (16). The step (18) of the plunger forms with the stepped interior (6) an intermediate chamber (22) connected with the low pressure zone through an opening (20). During the operation of the plunger (8) a dosed quantity of fuel is admitted through openings (24) into the gas space (12), which after ignition propels the plunger while water present in chamber (16) is being forced at a high pressure as a jet through the discharge orifice (26).