Patent ID: 7021498

Claim:
A spray urethane gun assembly comprising: a main body having a bore and a mixing chamber, an elongated spool longitudinally slidably mounted in said main body bore and movable between an extended position and a retracted position, an actuator for moving said spool between said extended position and said retracted position, a first and second inlet ports formed in said main body, a first and a second outlet ports formed in said main body, wherein said first inlet and first outlet are adapted to be connected with a source of polyol and wherein said second inlet and said second outlet are adapted to be connected with a source of isocyanate, a first axially extending fluid passageway formed in said spool, said first fluid passageway fluidly connecting said first inlet port with said first outlet port when said spool is in one of said retracted position or extended to thereby recirculate polyol to said polyol source, and said first fluid passageway fluidly connecting said first inlet port with said mixing chamber when said spool is in the other of said retracted or extended position, a second axially extending fluid passageway formed in said spool, said second fluid passageway fluidly connecting said second inlet port with said second outlet port when said spool is in said one of said retracted or extended position to thereby recirculate isocyanate to said isocyanate source, and said second fluid passageway fluidly connecting said second inlet port with said mixing chamber when said spool is in said other of said retracted or extended position, and a dispensing port formed in said main body and open to said mixing chamber.