Abstract: An apparatus for injecting a treatment chemical into an oil well produced using a subsurface pump, preferably a subsurface rotary pump, is described. Crude oil is pumped upward from a subsurface oil production zone through a central production pipe in the well. A small portion of produced fluid is diverted through a by-pass line interconnecting the production pipe and the annular space of the well between the production pipe and the well casing. A venturi nozzle comprising a throat of reduced diameter is mounted in the by-pass pipe. A suction pipe interconnects a chemical storage container containing a treatment chemical with the nozzle throat. Under the action of the venturi nozzle a suction pressure is created in the nozzle throat whereby the treatment chemical is drawn through the suction pipe and mixes with the fluid in the by-pass line thereby delivering the chemical to the well annulus.

Abstract: A fuel metering and actuation system includes a main centrifugal pump 16 supplying fuel to the combustor 18. Gear pump 50 takes suction from the main pump discharge and supplies actuators 42, 44, 45, 46 at high pressure. Variable set point pressure relief valve 56 operates to decrease the gear pump pressure level when high pressure is not required. Selection valve 21 directs discharge from the gear pump 50 to the combustor 18 when the main pump 16 supplied insufficient pressure for the fuel nozzles. Bypass line 30 around the selector valve with check valve 82 permits main pump 16 discharge fuel to be used for the actuator if the gear pump 50 becomes inoperative.