Pump sprayer

In a hand pump having a tubular plunger and a coaxial valve sleeve on the plunger shiftable freely between port opening and port closing positions in response to relative movement between the plunger and a barrel that telescopically receives the plunger and sleeve in frictional engagement with the sleeve, the improvement comprising:

• said plunger having a neck encircled by said sleeve and said neck being of diametrically reduced dimensions with respect to the remainder of the plunger,
• said neck including a radially inwardly tapering section at one end thereof and a radially outwardly tapering section at the opposite end thereof,
• there being a receiving port in the neck between said sloping sections thereof for communicating the inside of the plunger with the barrel when the sleeve is in its port opening position,
• said sleeve being generally hyperbolic in longitudinal cross section, having a radially inwardly bowed inner surface that is generally complemental to the neck of the plunger,
• said inner surface of the sleeve having a pair of radially outwardly extending, annular steps therein on opposite sides of said receiving port, presenting a pair of shoulders at the radially inward extent of said steps in position for alternate sealing engagement with the corresponding tapering sections of said neck as the sleeve moves between its port opening and port closing positions,
• said plunger being of mutually detachable two-part construction at said neck, a first of said parts containing said inwardly tapering section of the neck and the second of said parts containing said outwardly tapering section of the neck,
• said receiving port being located in said second part,
• said first part being provided with a first transversely extending annular end face circumscribing the tubular passage of the plunger, said second part being provided with a second transversely extending, annular end face abutting said first face in coaxial registration therewith and circumscribing a recess in the second part, said receiving port comprising a notch through said second face that communicates said recess with the exterior of the plunger,
• said second part being provided with a fluted stem projecting out of said recess and into the passage of the plunger, said stem being frictionally retained by said passage,
• said second part being provided with an alternative symmetrical set of outwardly tapering section, second annular face, receiving port notch, recess, and fluted stem opposite the aforementioned corresponding components such that said second part may be inverted end-for-end during assembly of the two parts.