Patent ID: 8590811

Claim:
In combination, a liquid pump that is not specially designed to produce foam to be used to produce foam and an arrangement for enabling the pump to produce foam, the pump having a liquid sucking inlet and a liquid expelling outlet, the arrangement including: a tank for containing foaming liquid, a discharge conduit, a supply conduit having a suction hole between its first and second ends, the suction hole being formed in a wall of the supply conduit and a filtering net screen; an end of the discharge conduit being adapted to be connected to the pump outlet; a first end of the supply conduit being adapted to be connected to the pump inlet; the supply conduit being adapted to be located in the tank so (1) the first end of the supply conduit is connected to the pump inlet and positioned such that the pump is operable if a level of the foaming liquid in the tank is below the first end, (2) the suction hole positioned such that the pump is operable if the level of the foaming liquid in the tank is above the suction hole, and (3) the second end of the supply conduit is exposed to air; the filtering net screen being in the discharge conduit so the filtering net screen can obstruct flow from the pump outlet; the area of the hole being such that liquid can not circulate via the hole, except during circulation of air in the supply conduit at a speed greater than a determined speed.