US 5,035,580 A · Bypass mode control for high pressure washing system

Abstract

A pressure washing system is disclosed which consists of a hydraulic pump driven by a variable speed internal combustion engine, a nozzle gun connected to the pump outlet, an unloader valve that senses the demand state of the nozzle gun for delivering water under pressure to the gun on demand, and for recirculating water to the pump inlet when the gun is in a non-demand position, and a throttle control device. The throttle control device senses pump outlet pressure and controls engine speed as a function of the demand/non-demand mode of the nozzle gun. Water is accordingly delivered at a high flow rate to the nozzle gun in the demand state, but recirculated at a much lower flow rate when the nozzle gun is in a demand state. The throttle control device also senses fluid pressure from the pump outlet to operate between engine starting and engine running modes. When hydraulic pressure is 0 or less than a predetermined threshold pressure, water is bypassed through a low-pressure hydraulic circuit to reduce the engine load during a manual start. After the engine has been started and the pump reaches the threshold pressure, the throttle control device operates to control the engine speed.

Claims17

Dependent claims

Control apparatus for producing mechanical motion in response to increasing fluid pressure after a predetermined minimum pressure has been reached, comprising:

a body defining an internal chamber, a fluid inlet leading into the chamber and a fluid outlet leading from the chamber;
piston means disposed in the chamber and movable in response to fluid pressure between first and second positions, said piston means defining fluid passage means disposed between said fluid inlet and said fluid outlet;
actuator means carried by the piston means for producing usable mechanical motion as a function of movement of said piston means;
and pressure actuated, normally open valve means disposed in said passage means for establishing fluid flow between said inlet and outlet in its open mode, and movable to a closed position when pressure at said inlet reaches a predetermined level to block fluid flow between the inlet and outlet, the valve means comprising a ball member, an annular seat member disposed in the passage means and forming part thereof, and spring means for urging the ball away from the seat member;
the piston means and valve means being together constructed and arranged so that, when the valve means closes and fluid flow is blocked, the piston means is movable from the first to the second position by fluid pressure at said inlet, whereby the actuator means is moved.

2 more elements

In a hydraulic system including hydraulic pumping means, variable speed motor means operably connected to drive the hydraulic pumping means and including throttle cable means actuatable to vary the speed of said motor means, the hydraulic pumping means having an inlet connected to a source of hydraulic fluid, an outlet for delivering pressurized hydraulic fluid, a utility device having demand and non-demand states connected to the pump outlet for utilizing the pressurized fluid, and unloader valve means disposed between the pump outlet and utility device for establishing fluid communication between the pumping means outlet and utility device when the utility device is in a demand state, and for causing hydraulic fluid to be recirculated from the pumping means outlet to the pumping means inlet when the utility device is in a non-demand state, the improvement which comprises:

a body defining an internal chamber, a fluid inlet leading into the chamber and a fluid outlet leading from the chamber;
first conduit means connecting the pumping means outlet with said fluid inlet and second conduit means connecting the fluid outlet to the pumping means inlet;
piston means disposed in the chamber and movable in response to fluid pressure between first and second positions;
actuator means carried by the piston means and movable as a function of movement of said piston means, the actuator means being operably connected to the throttle cable means;
and pressure actuated, normally open valve means disposed in the chamber for establishing fluid flow between said inlet and outlet in its open mode, and movable to a closed position when pressure at said inlet reaches a predetermined level to block fluid flow between the inlet and outlet;
the piston means and valve means being together constructed and arranged so that, when the valve means closes and fluid flow is blocked, the piston means is movable from the first to the second position by inlet fluid pressure, whereby the actuator means is moved to vary the speed of said motor means.

3 more elements

Dependencies are inferred from the claim text.

Bypass mode control for high pressure washing system

Life of this patent

Bypass mode control for high pressure washing system

Life of this patent

Abstract

Claims17