Patent ID: 8387657

Claim:
An internal valve system comprising: a first pressure sensor to detect an inlet pressure of a valve; a second pressure sensor to detect an outlet pressure of the valve; a controller operatively coupled to the first pressure sensor and the second pressure sensor to determine a position of the valve corresponding to one of a plurality of predetermined operational states of the valve including at least an open state, a closed state and a bleed state based on a comparison of the inlet pressure and the outlet pressure received by the respective first and second pressure sensors, the controller is to determine that the valve is in the closed state when a pressure differential between the inlet pressure and outlet pressure exceeds a valve opening differential pressure value, determine that the valve is in the bleed state when the differential pressure between the inlet pressure and the outlet is not equalized, and determine that the valve is in the open state when the pressure differential between the inlet and the outlet pressures reaches a valve opening differential pressure value; and an indicator to provide an indication that the valve is prepared to receive a detachable fluid pipe when the valve is in the closed state, the indicator to provide an indication that the valve is in the bleed state to prevent pumping of fluid through the valve prior to an equalization of pressure across the valve, and the indicator to provide an indication that the valve is prepared to pump fluid through the fluid pipe when the valve is in the open state.