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.

Monitoring systems and methods for a relief valve system. In one example, a monitoring system for a relief valve includes at least one tilt sensor coupled to one or more of a cover or a latch of the relief valve. The at least one tilt sensor is associated with an interface. Upon detection by the at least one tilt sensor that one of the cover is open or the latch is unlocked, a signal is transmitted by the interface indicating one or more of the cover is open or the latch is unlocked.

A pressure relief valve to balance the pressure between a cargo tank and the ambient atmosphere is described. The valve is so arranged that the velocity of the out flowing gas jet at no time is under a preset value when the valve is in open position. The valve comprises a valve body (2) designed to act against a valve seat (1) located in a structural outlet (5a) from the cargo tank, which valve body (2) is connected to a rod (7) extending into the structural outlet (5a) opening (5). The rod (7) is being supported and guided by a frame structure (6) extending into the structural outlet (5a) opening (5) and fixed to the structural outlet (5a).

A pressure relief valve to balance the pressure between a cargo tank and the ambient atmosphere is described. The valve is so arranged that the velocity of the out flowing gas jet at no time is under a preset value when the valve is in open position. The valve comprises a valve body (2) designed to act against a valve seat (1) located in a structural outlet (5a) from the cargo tank, which valve body (2) is connected to a rod (7) extending into the structural outlet (5a) opening (5). The rod (7) is being supported and guided by a frame structure (6) extending into the structural outlet (5a) opening (5) and fixed to the structural outlet (5a).

A thief hatch has a pressure relief valve and vacuum relief valve. Each valve may use a weighted pallet with a diaphragm that sits in operation on a seat surrounding a throat. Pressure from the interior of the tank, for the pressure relief valve, or pressure from atmosphere, for the vacuum relief valve, presses the diaphragm against the seat. If the pressure rises too much, the pallet and diaphragm will lift off the seat to relieve pressure.

A thief hatch has a pressure relief valve and vacuum relief valve. Each valve may use a weighted pallet with a diaphragm that sits in operation on a seat surrounding a throat. Pressure from the interior of the tank, for the pressure relief valve, or pressure from atmosphere, for the vacuum relief valve, presses the diaphragm against the seat. If the pressure rises too much, the pallet and diaphragm will lift off the seat to relieve pressure.

Monitoring systems and methods for a relief valve system. In one example, a monitoring system for a relief valve includes at least one tilt sensor coupled to one or more of a cover or a latch of the relief valve. The at least one tilt sensor is associated with an interface. Upon detection by the at least one tilt sensor that one of the cover is open or the latch is unlocked, a signal is transmitted by the interface indicating one or more of the cover is open or the latch is unlocked.

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.

A pressure relief valve to balance the pressure between a cargo tank and the ambient atmosphere is described. The valve is so arranged that the velocity of the out flowing gas jet at no time is under a preset value when the valve is in open position. The valve comprises a valve body (2) designed to act against a valve seat (1) located in a structural outlet (5a) from the cargo tank, which valve body (2) is connected to a rod (7) extending into the structural outlet (5a) opening (5). The rod (7) is being supported and guided by a frame structure (6) extending into the structural outlet (5a) opening (5) and fixed to the structural outlet (5a).

A pressure relief valve to balance the pressure between a cargo tank and the ambient atmosphere is described. The valve is so arranged that the velocity of the out flowing gas jet at no time is under a preset value when the valve is in open position. The valve comprises a valve body (2) designed to act against a valve seat (1) located in a structural outlet (5a) from the cargo tank, which valve body (2) is connected to a rod (7) extending into the structural outlet (5a) opening (5). The rod (7) is being supported and guided by a frame structure (6) extending into the structural outlet (5a) opening (5) and fixed to the structural outlet (5a).