Pressure/vacuum (PV) valve for fuel storage tanks, in-line pressure-vacuum valve test unit, and combination thereof
A flow-through pressure-vacuum valve includes a valve body having a tank-side opening and a vent-side opening. A pressure relief valve (e.g., a ball held in a corresponding seat by gravity) is positioned within a first passageway through the body. The ball is moved from the first valve seat to open the first passageway when pressure at the tank-side opening exceeds pressure at the vent-side opening by a predetermined pressure differential. A vacuum relief valve is positioned within another passageway (e.g., a serpentine passageway). The vacuum relief valve (e.g., also a ball held in a corresponding seat by gravity) is positioned within the serpentine passageway. Analogously, the ball is moved from the valve seat to open the serpentine passageway when pressure at the tank-side opening is less than the pressure at the vent-side opening by a predetermined pressure differential.
1. An in-line pressure-vacuum valve test system comprising:
an in-line pressure-vacuum valve test unit comprising:
a body having a tank-side end, a valve-side end, and an axial passageway extending entirely through the body from the tank-side end to the valve-side end, the axial passageway defining a tank-side port and a valve-side port;
a test port in a sidewall of the body;
a radial passageway extending from the test port into the axial passageway; and
a test probe having a hollow therethrough, the test probe inserted into the test port such that:
the test probe extends through the radial passageway and into the axial passageway;
the test probe seals the axial passageway between the tank-side port and a valve-side port; and
the hollow in the test probe cooperates with the axial passageway to create a path through the hollow in the test probe, into the axial passageway, and through the valve-side port;
a vent pipe having a first vent pipe segment coupled to the tank-side port; and
a pressure-vacuum valve coupled to the in-line pressure-vacuum valve test unit, wherein the pressure-vacuum valve comprises:
a valve body having a tank-side opening and a vent-side opening;
a pressure relief passageway that extends through the valve body from the tank-side opening to the vent-side opening;
a vacuum release passageway that extends through the valve body from the tank-side opening to the vent-side opening; and
a pressure relief valve within the pressure relief passageway, the pressure relief valve comprising:
a valve seat and a valve member, the valve member moved into the valve seat and held therein by gravity to close the pressure relief passageway, the valve member being moved from the valve seat to open the pressure relief passageway when pressure at the tank-side opening of the valve body exceeds pressure at the vent-side opening of the valve body by a first predetermined pressure differential;
a vacuum relief valve within the vacuum release passageway, the vacuum relief valve comprising:
a valve seat and a valve member, the valve member moved into the valve seat and held therein by gravity to close the vacuum relief passageway, the valve member being moved from the valve seat to open the vacuum relief passageway when pressure at the tank-side opening of the valve body is less than the pressure at the vent-side opening of the valve body by a predetermined pressure differential.
2. The in-line pressure-vacuum valve test system of claim 1 , wherein the pressure-vacuum valve is in-line with the vent pipe upstream of the in-line pressure-vacuum valve test unit.
3. The in-line pressure-vacuum valve test system of claim 2 , wherein the flow-through pressure-vacuum valve is positioned at a height of less than six feet (approximately 1.83 meters) from the surface from which the vent pipe emerges from a fuel storage tank, and the in-line pressure-vacuum valve test unit is in-line with the vent pipe below the flow-through pressure-vacuum valve.
4. The in-line pressure-vacuum valve test system of claim 2 , wherein the flow-through pressure-vacuum valve is positioned at a height of up to four feet (approximately 1.22 meters) from the surface from which the vent pipe emerges from a fuel storage tank, and the in-line pressure-vacuum valve test unit is in-line with the vent pipe below the flow-through pressure-vacuum valve.