hydraulic pipe fittings  including pipes and fittings, selection principles are: to ensure that the oil for laminar flow tube, pipe as short as possible to reduce the pressure loss; according to the working pressure, the installation location to determine the structure of pipes and connections to ensure that hydraulic adaptors and pipe fittings have sufficient strength, good seal; hydraulic pipe fittings  and pumps, valves and other connections shall determine its interface size diameter; easy assembly and disassembly. To ensure clean lubrication system and the supply line to the mechanical equipment clean and grease bearings must be installed to remove the pre-cleaning. Cleaning cleaning and pickling two kinds of kerosene. Will need to be cleaned to remove pipe and hydraulic pipe fittings , pipe with a cloth (to afford yarn) James kerosene to wipe the tube ends and joints soaked in kerosene cleaning, bsp adaptercoated with oil or grease filled, sealed at both ends and good to be installed; in the hydraulic system, whether it is a metal fitting, or the hose connector is prone to leakage problems. Pipeline to try to avoid the heat radiation and cooling water temperature is too high or too low spray and other place, especially hose fittings, piping and other equipment should not affect the operation of the host, to be safe, reliable, easy to work, observation, maintenance cloth.