flange screw connections

Flange fittings are generally used to connect lines to hydraulic pumps or hydraulic motors. They seal with an O-ring or sealing sleeve on a flat support surface of the pump or motor onto which the flange is tensioned using screws. The connection to pipes or hoses is made using cutting ring fittings or internal threads. A distinction is made between flange screw connections with a square hole pattern (the hole circle of the flange's mounting holes is crucial here: 35, 40 or 55 mm) or flanges with an SAE hole pattern of 3000 PSI / 6000 PSI. SAE flanges are usually clamped onto the flat support surface using special SAE flange halves using screws.