A pressure washer for delivering a liquid under high pressure has an inlet conduit connected to a liquid supply and an outlet conduit connected to a spray nozzle which can be operated to control the delivery of liquid through the nozzle. A bypass conduit enables recirculation of the liquid from the outlet conduit to the inlet conduit. A bypass system, disposed between the outlet conduit and the bypass conduit, includes a shuttle valve which moves between first and second positions at which it respectively blocks or opens the liquid path from the outlet conduit to the bypass conduit. The shuttle includes an axial passage from its inlet to its outlet side which passage has a narrowed jet outlet such that, when the liquid flows through the spray nozzle and the outlet conduit, the pressure drop across the shuttle moves the shuttle to the first position, while when the flow out the spray nozzle is stopped or significantly blocked, pressure on the side of the shuttle facing the spray nozzle rises to the level at the inlet side of the shuttle, which moves the shuttle to unblock the bypass conduit. A spring aids the return motion of the shuttle to the second position.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation in part of U.S. patent application Ser. No. 07/634,063, filed Dec. 26, 1990, now U.S. Pat. No. 5,086,975 which is a continuation of U.S. patent application Ser. No. 07/462,733, filed Jan. 19, 1990, now abandoned, which is a Continuation-In-Part of U.S. patent application Ser. No. 07/297,620, filed Jan. 17, 1989, now abandoned.
In a high-pressure cleaner of the type comprising a) a high-pressure pump (3), b) a motor driving said pump (3), c) a liquid supply (1,2) connected to the suction side (8) of the pump (3), d) a cleaning gun (4) connected to the delivery side (6) of the pump (3) through a delivery duct (10) and comprising a manually operable stop valve, and e) a bypass valve (16,17) adapted to in its open condition to allow flow frem the delivery side (6) to the suction side (8) of the pump (3), the main novel feature is f) flow-sensing mechanism (15,20) associated with the delivery duct (10) and adapted to open the bypass valve (16,17) when flow in the delivery duct ceases or decreases below a predetermined magnitude and to act upon it in the closing direction when flow is equal to or above the predetermined magnitude. With this arrangement, it is possible to utilize the positional change of the bypass valve member (16) for other purposes, such as switching-off the motor (not shown) for the pump (3) by a mechanism means of a normally closed switch (12) operated through a motion-delaying mechanism, such as a spring (35) in combination with a dashpot arrangement (27,36,37,13).
A washing machine including a boiler, a motor-driven pump controlled by a control device to pump warm water from the boiler to a spray gun through a water supply pipe, a check valve installed in the water supply pipe, a water return pipe for sending water from the water supply pipe back to the boiler, an unload valve for releasing pressure from the water supply pipe, a water volume detector connected to the water supply pipe between the unload valve and the spray gun to accumulate water from the water supply piping and being actuated when accumulated water volume drops below a predetermined value, a pressure detector mounted on the unload valve and actuated when the unload valve is opened, and a control device driven by the water volume detector to start the motor when the water volume detector is actuated, or driven by the pressure detector to turn off the motor when the pressure detector is actuated.
A low profile positive displacement pump system is disclosed. The pump system includes a gasoline powered engine with a vertically disposed crank shaft. The system also includes a piston pump with at least one horizontally disposed piston, and a pump shaft assembly which mounts onto the crank shaft. A base including a cavity for retaining the pump is provided. The engine mounts directly onto the base, and fixes the orientation of the pump shaft assembly with respect to a driven end of each piston. The pump shaft assembly includes at least one eccentric camming surface for contacting a driven end of the piston and for causing each piston to complete one stroke per revolution of shaft rotation. A high pressure piston pump base is disclosed, comprising a main body including an upper surface, wherein the upper surface is suitable for mounting directly to a mounting flange of a gasoline powered engine having a vertically disposed drive shaft. A central cavity is provided which is of a size and shape suitable for retaining a high pressure pump. The cavity is of a size suitable for holding the pump stationary during operation. A high pressure, low profile twin piston pump suitable for being driven by means of a gasoline powered engine with a vertically disposed crank shaft is also disclosed.
A low profile positive displacement pump system is disclosed. The pump system includes a gasoline powered engine with a vertically disposed crank shaft. The system also includes a piston pump with at least one horizontally disposed piston, and a pump shaft assembly which mounts onto the crank shaft. A base includes a cavity configured for retaining the pump. The engine mounts directly onto the base, and fixes the orientation of the pump shaft assembly with respect to a driven end of each piston. The pump shaft assembly includes at least one eccentric camming surface for contacting a driven end of the piston and for causing each piston to complete one stroke per revolution of shaft rotation. The base comprises a main body including an upper surface, wherein the upper surface is suitable for mounting directly to a mounting flange of the gasoline powered engine.
A safety shutoff system for steam and combination steam and water cleaners for permitting safe shutoff at the hand held spray gun thereof. The system includes a fluid reservoir connected to a first valve by a first conduit having a first pump for pumping fluid from the reservoir towards the first valve. A by-pass conduit connects the first valve to the fluid reservoir. An outlet conduit is connected to the first valve. The first valve controls fluid flow between the first conduit and the outlet conduit. The first valve blocks fluid flow from the first conduit into the outlet conduit upon detection of a pressure in the outlet conduit greater than a predetermined pressure such that fluid flowing from the first conduit passes into the by-pass conduit. The outlet conduit has a spray gun with a shutoff valve and a fluid heater between the first valve and the shutoff valve. A first switch detects the rate of fluid flow through the outlet conduit, and triggers deactivation of the heater when the rate of fluid flow through the outlet conduit between the first valve and the heater is less than a predetermined rate. A second switch detects the temperature of fluid in the outlet conduit between the heater and the shutoff valve, and triggers deactivation of the heater when the temperature of the fluid in the outlet conduit between the heater and the shutoff valve exceeds a predetermined temperature.
