Abstract: A polymer make-down system comprising: a mixing pump; a water source for providing a first quantity of water to piping at a suction end of the mixing pump; and a polymer source for providing a first quantity of polymer to piping at the suction end of the mixing pump; wherein the system is configured such that, after the first quantities of water and polymer have been mixed, a second quantity of water is provided so as to flush the mixture of the first quantities of water and polymer from the system. In another embodiment, the system further comprises a polymer check valve between the polymer source and the suction end of the mixing pump, wherein the polymer check valve is configured to prevent a flow of water to the polymer source. In another embodiment, the system further comprises recirculation piping coupled to piping at a discharge end of the mixing pump and to piping at an outlet end of the polymer check valve, wherein the recirculation piping is configured to be flushed by the second quantity of water.

Abstract: A vehicle electrical back-up circuit and method. Vehicle electrical devices normally receive the power required for their operation from a vehicle electrical system at a first voltage. An auxiliary storage battery is provided at a second, lower voltage. Preferably, charge is maintained in the battery by a charging circuit powered by the vehicle electrical system. A voltage booster circuit boosts the second voltage of the auxiliary storage battery back to the first voltage, providing auxiliary electrical power available for operating the electrical devices.

Abstract: A method and apparatus for improved flow control. A flow metering valve has an actuator formed of magnetic material which moves on response to an applied magnetic field to control fluid flow through the valve. A servo-control circuit receives a position command signal representative of a desired position of the actuator and produces an output command to produce a magnetic field in response thereto. The magnetic permeability of the actuator modifies the applied field and a magnetic field sensor measure the modified magnetic field to determine the position of the actuator. An actual position signal representative of the position of the actuator is negatively fed back to the servo-control circuit which produces an updated version of the output command.