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.

Abstract: Dual voltage isolating paint reservoirs for an electrostatic color change paint spray system. The reservoirs are formed from electrically insulated tubes which are wound into helices of different diameters and coaxially positioned to occupy the space otherwise occupied by a single helical reservoir tube.

Abstract: A paint color change system and method for sequentially supplying different color electrically conductive paints to an electrostatic applicator. Paint is supplied through a supply hose to a first isolated reservoir and the supply hose is purged and dried to form a voltage block. While paint is supplied through a first delivery hose from the first reservoir to an applicator, a second reservoir is cleaned, paint is supplied to the second reservoir through a supply hose, and the supply hose is purged of paint and dried to form a voltage block. Upon completion of coating with the first color paint, the first delivery hose is purged of paint and dried to form a voltage block and paint then is supplied from the second reservoir through a second delivery hose to the coating applicator. If the same color paint is applied from both reservoirs, the first delivery hose can be cleaned and dried after paint delivery from the second reservoir has started to permit continuous coating.