Pressure washer with spray nozzle valve allowing the buidling up of pressure in the outlet conduit when said valve is closed.

摘要

A pressure washer (10) for delivering liquid under high pressure has an inlet conduit (14) connected to a liquid supply, an outlet conduit (24) connected to a spray nozzle (30) with a valve (40) which is selectively openable for spraying liquid and a plurality of piston operated pumping cylinders connected in parallel between the inlet conduit (14) and the outlet conduit (24). A bypass conduit (72) recirculates liquid from the outlet (24) to the inlet conduit (14). A valve (62) in the bypass conduit (72) selectively permits leakage from the outlet conduit (24) when the spray nozzle valve (40) is open and opens communication between the outlet conduit (24) and the bypass conduit (72) when the spray nozzle valve (40) is closed and pressure builds up in the outlet conduit (24).