An expansion tank includes a tank body mounted inside a housing forming a sump, and defining an internal expansion volume. A fluid inlet opening in the tank body is in communication with the sump and the expansion volume. A combination valve may be disposed on a lower end of the tank to control fluid flow between the sump and the expansion volume. The valve may be a combination duckbill valve and umbrella valve. Fluid enters the expansion volume through the umbrella valve when sump pressure exceeds expansion volume pressure by a first predetermined amount, and fluid exits the expansion volume through the duckbill valve to the sump when expansion volume pressure exceeds sump pressure by a second predetermined amount. The tank body may include a cover on which an inlet tube is formed.

An expansion tank includes a tank body mounted inside a housing forming a sump, and defining an internal expansion volume. A fluid inlet opening in the tank body is in communication with the sump and the expansion volume. A combination valve may be disposed on a lower end of the tank to control fluid flow between the sump and the expansion volume. The valve may be a combination duckbill valve and umbrella valve. Fluid enters the expansion volume through the umbrella valve when sump pressure exceeds expansion volume pressure by a first predetermined amount, and fluid exits the expansion volume through the duckbill valve to the sump when expansion volume pressure exceeds sump pressure by a second predetermined amount. The tank body may include a cover on which an inlet tube is formed.

A thermodynamic valve for retaining vapours and gases and relieving pressure and vacuum for use in the venting of tanks or reservoirs of combustible liquids (fluids), said valve comprising: upper diaphragm ring (3a) and lower diaphragm ring (3b) that act through the thermodynamic action of the positive and negative pressures inside positive pressure (4) and negative pressure (5) chambers fixed to one another, a cap (2) screwed on the body of positive pressure chamber (4) and having upwardly directed lateral openings and a rupture seal (1) fitted in the upper section of cap (2). A base (5.1) with an inner fire-break fabric (6) is positioned on the inner lower section of negative pressure chamber (5) and connected to the fuel tank venting pipe.

A thermodynamic valve for retaining vapours and gases and relieving pressure and vacuum for use in the venting of tanks or reservoirs of combustible liquids (fluids), said valve comprising: upper diaphragm ring (3a) and lower diaphragm ring (3b) that act through the thermodynamic action of the positive and negative pressures inside positive pressure (4) and negative pressure (5) chambers fixed to one another, a cap (2) screwed on the body of positive pressure chamber (4) and having upwardly directed lateral openings and a rupture seal (1) fitted in the upper section of cap (2). A base (5.1) with an inner fire-break fabric (6) is positioned on the inner lower section of negative pressure chamber (5) and connected to the fuel tank venting pipe.

A pressure relief valve for a reservoir has a housing body forming first and second subchambers in fluid communication. A first opening in a bottom surface of the housing body forms a first valve seat. At least one second opening in the bottom surface forms a second valve seat along an outer perimeter. A diaphragm member is biased against the second valve seat and is configured to deflect off of the second valve seat under a negative pressure. A sealing ball is gravitationally biased against the first valve seat and raises off the first valve seat in response to a positive pressure. A cover sheet on an upper surface of the housing body partially encloses the chamber and traps the sealing ball in the first subchamber. The cover sheet includes an aperture aligned with the second subchamber providing an ambient pressure port coupled to ambient atmosphere.

A thermodynamic valve for retaining vapours and gases and relieving pressure and vacuum for use in the venting of tanks or reservoirs of combustible liquids (fluids), said valve comprising: upper diaphragm ring (3a) and lower diaphragm ring (3b) that act through the thermodynamic action of the positive and negative pressures inside positive pressure (4) and negative pressure (5) chambers fixed to one another, a cap (2) screwed on the body of positive pressure chamber (4) and having upwardly directed lateral openings and a rupture seal (1) fitted in the upper section of cap (2). A base (5.1) with an inner fire-break fabric (6) is positioned on the inner lower section of negative pressure chamber (5) and connected to the fuel tank venting pipe.

A thermodynamic valve for retaining vapours and gases and relieving pressure and vacuum for use in the venting of tanks or reservoirs of combustible liquids (fluids), said valve comprising: upper diaphragm ring (3a) and lower diaphragm ring (3b) that act through the thermodynamic action of the positive and negative pressures inside positive pressure (4) and negative pressure (5) chambers fixed to one another, a cap (2) screwed on the body of positive pressure chamber (4) and having upwardly directed lateral openings and a rupture seal (1) fitted in the upper section of cap (2). A base (5.1) with an inner fire-break fabric (6) is positioned on the inner lower section of negative pressure chamber (5) and connected to the fuel tank venting pipe.

A P/V valve that can be positioned at a working height above grade (i.e., a height reachable by a service technician positioned at grade) while still providing appropriate resistance to fire and explosion by venting to atmosphere at an appropriate height above grade (e.g., 12 feet) is disclosed. In certain exemplifications of the present disclosure, the P/V valve features a diaphragm actuated two-way poppet valve actuatable by a valve piston. In alternative exemplifications of the present disclosure, the P/V valve is positioned intermediate grade and the distal end of a P/V valve riser pipe and is contained in a vault fluidly connected to the P/V valve riser pipe, the P/V valve locally venting in the vault, which is hermetically sealed to the P/V valve riser pipe.

A P/V valve that can be positioned at a working height above grade (i.e., a height reachable by a service technician positioned at grade) while still providing appropriate resistance to fire and explosion by venting to atmosphere at an appropriate height above grade (e.g., 12 feet) is disclosed. In certain exemplifications of the present disclosure, the P/V valve features a diaphragm actuated two-way poppet valve actuatable by a valve piston. In alternative exemplifications of the present disclosure, the P/V valve is positioned intermediate grade and the distal end of a P/V valve riser pipe and is contained in a vault fluidly connected to the P/V valve riser pipe, the P/V valve locally venting in the vault, which is hermetically sealed to the P/V valve riser pipe.

A liquid storage tank has a breathing valve that vents the tank's headspace at a high-pressure value and admits an ambient gas at a low-pressure value. A controller generates a first control signal when the percentage of the catalyst gas is less than a catalyst threshold, a second control signal when the percentage of the catalyst gas exceeds the catalyst threshold, and a third control signal when the pressure in the headspace is equal to a low-pressure threshold between the breathing valve's low-pressure value and high-pressure value. The first valve is only opened to output inert gas at a discharge pressure greater than the breathing valve's high-pressure value in response to the second control signal. The second valve is only opened to output inert gas at a discharge pressure that is between the breathing valve's low-pressure value and high-pressure value in response to the third control signal.