Recirculating paint system having a valved quick disconnect fluid coupling assembly

A method of connecting and disconnecting a fluid conduit to a nozzle of a spray gun such that during connection and disconnection excess fluid does not escape from the conduit, the steps of the method comprising:

• connecting a fluid fitting to said spray gun, said fluid fitting including a cylindrical stem having an outer periphery and a fluid passage;
• connecting a valve body to a discharge end of said conduit, said valve body having a bore extending therethrough for passing said fluid to said fluid passage;
• positioning an annular seal mechanism having a first end face opposite a second end face and being in sealed relation with a wall of said bore, said annular seal mechanism having a central passage extending between said first and second end faces thereof and a cross-section of said central passage being less than the cross-section of said outer periphery, said second end face forming a conical skirt;
• biasing a closure member against the first end face to prevent fluid passage through said bore;
• inserting the stem into the central passage through the second end face whereby the conical skirt expands outwardly as the outer periphery is brought into sealed engagement with the second end face before the stem engages the closure member to inhibit flashback of the fluid;
• continuing the insertion of the stem until the stem engages the closure member;
• forcing the closure member from engagement with the first end face to enable fluid flow through the fluid passage;
• and
• withdrawing the stem from the central passage whereby the closure member is brought into sealed engagement with the first end face before said outer periphery disengages the second end face to inhibit flashback of the fluid.

In a recirculating fluid supply system including

• a spray nozzle for discharging a fluid,
• conduit means, including a conduit having first and second end portions, for receiving from a supply and supplying the fluid to said spray nozzle in an amount in excess of that required and for returning to the supply the excess fluid not discharged from the spray nozzle,
• a first fluid connection means for fluidly connecting the first end portion of the conduit to the fluid supply, and
• a second fluid connection means for fluidly connecting the second end portion of the conduit to the spray nozzle,
• the improvement wherein said second fluid connection means comprises
• a first valve body fluidly connected to said spray nozzle,
• a second valve body having a fluid bore extending therethrough, said second valve body fluidly connected to said conduit taxi connectable to said first valve body,
• said second valve body including a seal means mounted in the bore for assisting in sealing said second valve body, said seal means having a first end face opposite a second end face and a fluid passage extending between the end faces, said second end face forming an inwardly tapered skirt, a closure member mounted in said fluid passage for movement between a first position to a second position, respectively, for preventing and permitting the fluid to pass through said fluid passage and said bore, said closure member being normally biased into sealing engagement with the first end face and in covering relation with the fluid passage opening thereon, and
• said first valve body including an elongated tubular stem which is adapted to be inserted into said fluid bore to progressively establish sealing engagement with the second end face as said skirt expands outwardly before said stem engages said closure member thereby inhibiting flow or flashback of fluid, with said stem thereafter engaging the closure member and moving the closure member from its first position in covering engagement with the seal means and into its second position spaced from the first end face to permit flow.