This invention relates to pressure washers, and, more particularly, to a pressure washer which is equipped with a flow control switch for shutting off power to the pressure washer if fluid is not flowing through the pressure washer.
Pressure washers are well known devices for delivering water or other washing fluid under high pressure, e.g., about 1200 to 2000 psi. Pressure washers conventionally include a pump assembly which includes a plurality of pumping pistons which are driven by an electric motor or an internal combustion motor. Fluid is commonly supplied to the pump by a garden hose. Pressure washers of this type are described in U.S. Pat. Nos. 5,068,975, 5,067,654, and 5,174,723.
Conventional electric pressure washers utilize a main power switch which requires the operator of the pressure washer to physically move the switch from one position (off) to another position (on) to supply electrical power to the electric motor of the pressure washer. If the power cord is plugged into an electric outlet, the electric motor will start and will continue to run until the switch is physically moved to the off position.
If the electric motor is started without water or other washing fluid being supplied to the pressure washer, the pump might overheat and fail without the cooling and lubrication which the water provides. Electrical and mechanical safety hazards could also result from that type of operation.
If the flow of water is stopped after the pressure washer is turned on, for example, if a kink develops in the garden hose which supplies the water or if another person turns off the water faucet, similar difficulties could arise if the motor was not turned off and the pump continued to run.
Many current pressure washers include a by-pass valve and a by-pass passage which activates when the high pressure gun is deactivated. Since the electric motor and pump continue to run, it is necessary to recirculate the water in a by-pass mode to cool the pump. Many units have a time limit of around five minutes during which the unit may be operated in the by-pass mode. If this time limit is exceeded, damage to the pump can result.