Maximum liquid level control valve

Abstract

A maximum liquid level control valve for limiting the flow of liquid petroleum gas into a tank having a valve body, a float pivotally attached to the valve body, a closure flap, a spring acting between the valve body and the closure flap, and a cam device movable by the float. The control valve which is mounted to a flange welded to the side wall of the tank has a valve seat and a passage for liquid to flow through the valve body into the tank. The closure flap is movable toward the valve seat to a closed position and away from the valve seat to an open position. The closure flap is movable to the closed position under incoming liquid pressure. When the liquid level in the tank is below the maximum liquid level, the cam device acts on a stem which is attached to the closure flap. With the cam acting on the stem, the closure flap cannot be moved to the closed position in response to incoming liquid pressure. When the maximum liquid level is reached, the cam device rotates unblocking the stem, the spring constant of the spring is overcome by incoming liquid pressure, and the closure flap is moved to the closed position. When the tank is filled, the source of liquid petroleum gas is shut off and any pressure trapped within the control valve and working against the closure flap is released through a bleeder hole. Then the spring returns the closure flap from the closed position to the open position.

Dependencies are inferred from the claim text.