| 摘要 |
A pressure washer for delivering liquid under high pressure has an inlet conduit connected to a liquid supply, an outlet conduit connected to a spray nozzle with a valve which is selectively openable for spraying liquid and a plurality of piston operated pumping cylinders connected in parallel between the inlet conduit and the outlet conduit. A bypass conduit recirculates liquid from the outlet to the inlet conduit. A valve in the bypass conduit selectively permits leakage from the outlet conduit when the spray nozzle valve is open and opens communication between the outlet conduit and the bypass conduit when the spray nozzle valve is closed and pressure builds up in the outlet conduit. Each piston in a pumping cylinder is driven to reciprocate through its pumping cylinder. The piston also moves laterally because there is an eccentric connection between the piston and a common rotary pin for each of the pistons of each of the pumping cylinders. Appropriate valves direct liquid flow only from the inlet conduit through the pumping cylinders to the outlet conduit. Additional liquid may be supplied to and mixed with the liquid in the outlet conduit through a valve at a venturi connection in the outlet conduit. A pressure gauge connected with the outlet conduit measures pressure there.
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