Patent ID: 8459203

Claim:
A powder coating feed method using a dense phase powder pump having at least one feed chamber fitted with a powder intake valve and a power outlet valve, the method comprising: (a) generating a partial vacuum in said at least one feed chamber to aspirate coating powder into the feed chamber through the open powder intake valve while the powder outlet valve is closed; (b) closing the powder intake valve and opening the powder outlet valve; (c) introducing a compressed gas into the feed chamber to discharge the coating powder from the feed chamber through the open powder outlet valve while the powder intake valve is closed; (d) closing the powder outlet valve and opening the powder intake valve; wherein generating a partial vacuum in the feed chamber by a control signal during the cycle segment (a) or when passing from the cycle segment (d) to the cycle segment (a) no earlier than simultaneously with generating a control signal to open the powder intake valve, wherein the initial partial vacuum buildup in the feed chamber takes place no earlier than simultaneously with the beginning of opening the powder intake valve, wherein generating the partial vacuum using the control signal during the cycle segment (a) or when passing from the cycle segment (d) to the cycle segment (a) at a predetermined delay time after the control signal opening the powder intake valve was generated, and wherein the partial vacuum buildup in the feed chamber begins at a defined time delay after opening the powder intake valve, using a pinch valve as the powder intake valve and as the powder outlet valve, wherein the pinch valves further comprise a flexible hose that separates a valve duct on the inner hose side from a pressure chamber on the hose outside and in that the hose is radially compressed shut by the pressure of an applied compressed gas introduced into the pressure chamber, thereby closing the valve duct.