Pump apparatus and system for containing and metering uniform pulses of

Abstract

A system is provided for delivering controlled quantities of a steady stream of a fluid to an application zone. The system includes a positive displacement pump for producing uniform pulses of small quantities of said fluid. The pump has a piston housing with an elongated bore extending from a first open end to a position proximate a second closed end and a pumping chamber region at said second end. The pumping chamber is provided with a pumping fluid inlet and a pumping fluid outlet. A reciprocating and rotating piston, is positioned for rotational and reciprocating motion within said elongated bore of said piston housing, from a first position in which said piston substantially occupies the space within said pumping chamber and displaces pumping fluid from said pumping chamber to a second position in which said piston is substantially removed from said pumping chamber and draws pumping fluid into said chamber. A barrier fluid inlet means is provided at a position which is between said elongated bore first end and said pumping chamber and adjacent said piston. Barrier fluid is delivered to the elongated bore at a pressure which is greater than the maximum fluid pressure within said pumping chamber, in order to produce a positive pressure differential which precludes migration of pumping fluid from said pumping chamber, along the piston, to said first open end. A mixing chamber is provided for mixing pumped fluid with air. The mixture is delivered to an application zone through an elongated restricted flow conduit, whereby said fluid and said air transform from a pulsed flow at said flow conduit first end to a steady flow at said second end.