Patent ID: 7810744

Claim:
In a fluid reservoir for a paint spray gun comprised of a receptacle and a lid that can be placed thereon, wherein the lid has provision for placing the fluid reservoir on the paint spray gun or an adapter and wherein the receptacle has a ventilation port that can be opened and closed by means of a valve, the improvement comprising: a double seat valve with two valve seats one after the other in the direction of flow and separated from one another; said double seat valve being comprised of (a) the ventilation port formed as a tapered through hole in a wall of the receptacle to define a first valve seat; (b) an open hollow cylinder surrounding said tapered through hole, said open hollow cylinder having a preselected external diameter, oriented normal to the receptacle wall, and having an exterior surface extending from the receptacle wall to its open end, said exterior surface of said hollow cylinder defining a second valve seat adjacent said receptacle wall; (c) a closure element received on said open hollow cylinder and being in engagement with the exterior surface, said closure element being composed of a hollow cylindrical base body having an internal diameter substantially equal to said preselected external diameter of said open hollow cylinder, and a cap formed on one end of said base body; (d) said cap including a support part that extends from said cap and terminates at its lower end in a tapered plug for cooperating with said tapered hole to form a first tight seal; (e) a portion of said hollow cylindrical base body contacting said second valve seat defined by said exterior surface of said hollow cylinder adjacent said receptacle wall to form a second tight seal (f) said closure element being displaceable relative to said open hollow cylinder between a first position, in which the ventilation port is closed off by the double seat valve and any leakage of liquid from the receptacle through the first tight seal will be trapped by the second tight seal, and a second position, in which the double seat valve is open and an equalization of pressure is achieved via ventilation flow.