Hydraulic fittings connect pipes, hoses to components (pumps, valves, cylinders, etc.) or together to create a system through which hydraulic oil can flow without leakage, fittings should be able to withstand high pressure and leak proof, and changes in fittings allow designers to change flow direction, split flow direction, and change elevation of lines.
Fitting geometry includes plugs, unions, elbows, crosses, and others. Care is needed to identify the threads of the connection. Some connectors from one standard seem to enter another standard port, but there is not enough thread engagement to ensure safety.
Connection types include: welding (socket welding, butt welding, sliding sleeve, etc.), thread, flange connection, barb connection, quick disconnection, push connection, 37 ° flared connection, 24 ° tapered connection, reverse flared connection, nail lock, end face seal, push connection, etc.
Some important considerations in selecting the type of fitting are working pressure, vibration, fitting type, required accessories, pipe size, flow, material and price of conductor or component, and the hydrodynamic industry is trying to turn to fittings with elastic seals to prevent leakage.