Abstract: An improved method and apparatus for cleaning liquid-carrying hoses, and the like. A suitable cleaning solvent is passed under pressure through the hose. The pressure of the solvent delivered to the hose is measured and used to control the pressure of compressed air mixed with the solvent to maintain a turbulent flow of a predetermined mix ratio for various solvent pressures. The turbulent solvent/compressed air mixture increases scrubbing of the hose to reduce the cleaning time and the quantity of solvent required to clean the hose.

Abstract: This invention concerns a system for insuring and accurately controlling the turbulent flow of a pressurized mixture of a gas and a cleaning fluid for purging and cleaning ducts. The pressures of cleaning fluid and the gas are continuously sensed and transduced into electrical signals for controlling valves for the pressurized gas to maintain and insure its pressure at a predetermined amount relative to the pressure of said cleaning fluid, so that when the gas and fluid are mixed in a turbulator, turbulent flow is insured. The improvements of this circuit include a pressure sensor transducer for sensing the pressure of the input of the air to the turbulator and feeding it back to the main air pressure transducer for accurately maintaining a predetermined ratio between the gas and cleaning fluid pressures within less than about 1 psi in at least pressures of 150 psi. A pressure warning signal indicates when the gas and/or cleaning fluid pressure is too low to produce effective turbulent flow.