Suck-back liquid dispensing valve and valve assembly

Abstract

A suck-back valve selectively actuatable for dispensing liquid in its open condition from an associated liquid storage container, and for avoiding continued presence of excess dispensed liquid about the exit orifice in the closed condition of the valve, is formed at least in part of a spring member and a pin. The spring member includes a distal web that defines a valve seat and a dispensed liquid exit orifice, a proximal web, and a plurality of flexibly elastic bands helically connecting the distal and proximal webs. The pin includes an elongated shaft having a proximal end secured to the proximal web and carrying a substantially hollow frustoconical cone at its distal end. The cone has an outer valving surface for releasable abutment with the valve seat and the shaft has a bore of predetermined cross-sectional extent defined longitudinally along and within the shaft to create a continuous fluid passageway through and along the pin. Dispensed liquid remaining proximate the exit orifice is sucked back into the liquid container through the shaft bore as the valve returns from its open to its closed condition under the return urgency of the elastic bands.