Hochdruckreiniger mit Bypass.

摘要

A pressure washer (10) for delivering a liquid under high pressure has an inlet conduit (30) connected to a liquid supply and an outlet conduit (50) coupled to a spray nozzle (18) which can be operated to control the delivery of liquid through the spray nozzle (18). Liquid, e.g., water, is pumped from the inlet (30) to the outlet conduit (50), elevating its pressure significantly. A bypass conduit (56) enables recirculation of the liquid from the outlet (50) to the inlet conduit (30). A bypass system (14), disposed between the outlet conduit (50) and the bypass conduit (56), includes a shuttle valve (70) which moves between first and second positions at which it respectively blocks or opens the liquid path from the outlet conduit (50) to the bypass conduit (56). The shuttle (70) is such that, when the liquid pressure on the side of the shuttle (70) facing the spray nozzle (18) is approximately equal to or greater than the liquid pressure in the outlet conduit (50), the shuttle (70) moves to a position which unblocks the bypass conduit (56), approximately equalizing the pressure across the shuttle (70) and protecting the washer's (10) components and enhancing its operability. A nozzle seal arrangement in the pressure washer's pump (12) comprises a pair of seals (230,236) between each piston (190) and cylinder (32) wall of the pump (12). One of the seals pivots in response to side to side wobbling of the piston (190) while maintaining proper sealing conditions.