Standard_Parts_Catalogue

Page 1614 | 3.5 Controlling, Venting, Sealing of Liquids and Gases GN 774.1 Breather Caps Plastic, with Membrane 1 d 1 2 d 2 3 Color How to order 1 2 3 GN774.1-70-G1 ¼ -RT Breather caps GN 774.1 prevent the build up of a pressure drop over liquids in a tank. They are used when a tank has to be rapidly emptied. The elastic mem- brane ensures a sufficient supply of air to prevent any vacuum build-up in the tank. Besides that, the back pressure behind the membrane will prevent the escape of any liquid in the tank to the outside, especially during trans- port. If the tank is turned upside down with the additional back pressure from the liquid, it will be sufficient to keep the outlet firmly shut. see also... • Filler Strainer GN 664 / GN 664.1 → Page 1634 / 1636 • Breather Caps GN 663 → Page 1612 Information • Upper part (cap) Plastic (Polypropylene PP) - - Temperature resistant up to 50 °C - - Red, RAL 3000 RT Membrane and flat seal EPDM (Ethylene propylene diene rubber) - - Green, RAL 6001 GN Membrane and flat seal FKM (Fluor rubber, Viton ® ) - - Symbol black printed • Lower part (threaded part) Plastic (Polypropylene PP) - - Temperature resistant up to 50 °C - - Black • Elastomer Characteristics → Page 2158 • Plastic Characteristics → Page 2158 • RoHS Specification 3 1 2 d 1 d 2 d 3 d 4 l 1 l 2 Air flow rate in l / min. Pressure drop in mbar FKM EPDM 70 G 1 1 ⁄ 4 33 68,5 17 59 50 360 370 40 320 330 30 260 280 20 210 230 10 140 160  5 110 130 Sealing membrane Original design TVD.