Abstract: Apparatus and method for controlling the operation of a plurality of nozzles for spraying a liquid substance on a product. The nozzles have different flow volumes and are located adjacent the product. A sensor measures the quantity of the product, and a control responsive to the sensor opens selected nozzles to produce a desired ratio of the quantity of the substance to the quantity of the product. There is further provided another sensor for measuring the quantity of the substance, the control being responsive to the two sensors and operative to determine the actual ratio of the quantity of the substance to the quantity of the product and to adjust the actual ratio to match the desired ratio.

Abstract: A liquid flow system comprising a bidirectional liquid pump, a bidirectional electric motor coupled to drive the pump, and a liquid flow line having the pump connected therein. The system further comprises a motor control circuit connected to power the motor in either the forward or the reverse direction. The control circuit includes a switch for connecting the motor windings to the power lines, the switch being operable to instantly reverse the power connections when the motor is operating in the forward direction and thereby powering the motor-pump to an instant stop and then immediately powering the motor in the reverse direction. The pump thereby instantly reverses the liquid flow in the flow line and abruptly terminates the flow. To quickly start the flow again in the forward direction later on, a priming loop is connected to the pressure side of the pump, so that the pump is able quickly to develop pump pressure.