EN 764 Steel Sheet Metal Breather Valve Caps, with Double Valve

Part Number F - With filter	Part Number FD - With filter and double valve (only for d~1~ = 81 mm)	d₁	d₂ Pipe thread		Bayonet mount	d₃	d₄	d₅	d₆	l₁	l₂	l₃	l₄	l₅ ≈	l₆	A/F	Opening pressure in mbar Type FD


764-47-G1/4-F		1.85	G 1/4	-	-	0.28	2.05	1.57	1.06	0.39	0.20	2.01	1.38	0.51	2.60	0.67	-
764-47-1/4NPT-F		1.85	-	1/4 NPT	-	0.28	2.05	1.57	1.06	0.39	0.20	2.01	1.38	0.51	2.60	0.67	-
764-47-BA-F		1.85	-	-	BA	0.28	2.05	1.57	1.06	0.39	0.20	2.01	1.38	0.51	2.60	0.67	-
764-81-3/4NPT-F		3.19	-	3/4 NPT	-	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	-
	764-81-3/4NPT-FD	3.19	-	3/4 NPT	-	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	350
764-81-G3/4-F		3.19	G 3/4	-	-	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	-
	764-81-G3/4-FD	3.19	G 3/4	-	-	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	350
764-81-BA-F		3.19	-	-	BA	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	-
	764-81-BA-FD	3.19	-	-	BA	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	350

d₁	d₂ Pipe thread		Bayonet mount	d₃	d₄	d₅	d₆	l₁	l₂	l₃	l₄	l₅ ≈	l₆	A/F	Opening pressure in mbar Type FD

1.85	G 1/4	1/4 NPT	BA	0.28	2.05	1.57	1.06	0.39	0.20	2.01	1.38	0.51	2.60	0.67	-
3.19	G 3/4	3/4 NPT	BA	0.67	3.27	2.83	1.93	0.63	0.47	2.76	1.65	0.67	3.15	1.18	350

Description of Function


						EN 764 filler breathers with double valve are normally used when the fluid container is under pressure, yet air has to flow in from the outside in case of underpressure (decreasing fluid level). This is achieved by combining two valves (check / bypass valve). The inlet valve allows air to enter at an underpressure of 30 mbar or higher. The second valve only opens at an overpressure of > 350 mbar. The air filter prevents contamination of the fluid from outside (dust). It is made of PU foam with a grade of filtration of 40 µm. The overpressure inside the container ensures that the air volume, which is flowing in or escaping due to the fluctuating fluid level, is kept to a minimum. This reduces filter fouling and substantially increases the service life, especially in dusty environments. In addition, a pressurized container has a positive effect on the function of the pump and prevents the formation of foam. The valve seal ensures that no fluid will leak, especially if the fluid is strongly moved or during transport.

						Air flow rate [l/min] as a function of the pressure difference Δp [mbar] container / outside space (type F with filter).

						Pressure gradient Δp [mbar] in the container as a function of the air flow rate [l/min] at a valve opening pressure of 350 mbar (type FD with filter and double valve).