Patent ID: 6105832
Filing Date: 2000-08-22
Classification: B05C,F16K

Abstract:
A dispensing head, comprising:a valve body having a longitudinal body passageway formed therethrough between a distal end and a proximal end, the body passageway having a first section at the distal end having a first diameter and a second section at the proximal end having a second, smaller diameter, and an annular shoulder therebetween, the valve body further having a trigger inlet passageway at the distal end communicating with the first section;a dispensing liquid inlet tube formed through the valve body and communicating with the second section;a spring disposed within the body passageway first section and abutting the annular shoulder; anda spool valve/piston assembly disposed within the body passageway and extending through the spring, the spool valve/piston assembly comprising:a spool valve head formed at a proximal end of the spool valve/piston assembly and disposed within the second section, the spool valve head including a valve head passageway formed through a central, longitudinal axis of the spool valve head;a channel formed from an exterior surface of the spool valve/piston assembly to the valve head passageway for fluid communication therebetween;a first seal disposed around the spool valve/piston assembly and having the second diameter, the first seal located between the spool valve head and the spring; anda second seal disposed around the spool valve/piston assembly and having the first diameter, the second seal located between the spring and the trigger inlet passageway;wherein application of gas pressure to the trigger inlet passageway moves the spool valve/piston assembly in the proximal direction against the spring bias force, thereby aligning the channel with the dispensing liquid inlet tube, allowing dispensing liquid to enter the valve head passageway; andwherein removing the gas pressure from the trigger inlet passageway allows the spring bias force to move the spool valve/piston assembly in the distal direction, blocking the dispensing liquid inlet tube with the spool valve head and creating a cavity in the second section proximal of the spool valve head operative to suck back any dispensing liquid away from the proximal end of the valve body.