Abstract: An injector pump for introducing metered amounts of fluid into a process line which pump typically is actuated by a gas powered timing relay. A diaphragm or other impermeable member mounted in the pump housing defining a pump chamber for the fluid to be pumped and a piston chamber for a piston having a plunger sliding in a plunger guide to define a pressure chamber between the plunger and the diaphragm. A high pressure seal is carried in the plunger guide to provide sealing about the plunger when there is a high pressure in the pressure chamber, while permitting leakage along the plunger when there is a low pressure in the pressure chamber, thereby providing for pumping of measured amounts of fluid which may be under high pressure and/or highly corrosive, while maintaining isolation between the pump mechanism and the fluid.

Abstract: An oscillating or timing valve, sometimes known as an air relay, suitable for use with a chemical injector. A valve housing with sliding poppet, sliding piston and adjustable needle, with the poppet movable in one direction to close an exhaust port and with the piston movable in the opposite direction to engage the poppet and close the outlet or drive port and open the exhaust port. The piston oscillates between the drive port open and the drive port closed conditions, with the timing adjusted by varying the needle orifice and the size of the chamber fed through the needle orifice. The oscillating valve does not utilize any diaphragms or springs.