Patent ID: 7156896

Claim:
A separating tank assembly for a dental vacuum system, the separating tank assembly comprising: a separating tank connected to a vacuum pump, the separating tank having an inlet for liquid and solid debris; and a drain tank in fluid communication with the separating tank via an outlet and an intermediate check valve; a control valve secured to the drain tank and coupled with the separating tank via a tube, the control valve selectively opening the drain tank (1) to the separating tank via the tube and (2) to atmosphere; a level sensor disposed in the drain tank, the level sensor supplying a level signal to the control valve; and a sewer drain in fluid communication with the drain tank via a drain check valve, wherein vacuum pressure in the separating tank and the drain tank maintains the intermediate check valve in an open position enabling fluid communication between the separating tank and the drain tank, and wherein vacuum pressure in the separating tank and the drain tank maintains the drain check valve in a closed position blocking fluid communication between the drain tank and the sewer drain, wherein when the level sensor detects that a predetermined level in the drain tank has been reached, the control valve opens the drain tank to atmosphere such that a pressure differential between the separating tank and the drain tank causes the intermediate check valve to close and the drain check valve to open.