Abstract: A pinch valve includes a body with a passageway extending therethrough, a flexible sleeve mounted within the body and surrounding the passageway, and a cavity between the sleeve and the body. An inlet opening provides control fluid flow into the cavity, while an outlet opening allows for fluid exhaust from the cavity. The diameters of the inlet and outlet openings are fixed, with the inlet diameter being smaller than the outlet diameter. A two-way control valve opens and closes the outlet opening, and thereby controls opening and closing of the pinch valve.

Abstract: A foam marking system is provided with separate tanks for water and foam concentrate. A water pump and a concentrate pump deliver water and concentrate from the respective tanks to a mixing chamber at a pre-selected ratio. The water pump is controlled by a master control, while the concentrate pump is controlled by a slave control depending from the master control. The master control generates and output signal which is sent to both the water pump and the slave control, such that the slave control and concentrate pump operate as a function of the master control and water pump, so that the selected mix ratio can be maintained, regardless of the output level of the foam from the system. A foam generation chamber connected to the mixing chamber and to an air source generates foam when the foam solution is mixed with air.