Abstract: 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.

Abstract: 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.