Hydraulic hose and fittings in the hydraulic system application note which
In the hydraulic system design, selection of hoses and hose fittings are usually the last stage in the design and selection of importance can easily be underestimated or ignored . In fact , hose and  Hydraulic ferrules  with the functionality of the entire system and plays a vital role in life .1 , hoseGenerally , a synthetic rubber, rubber hose inner layer , used to keep the fluid transfer hose tube. Hoses need for the wires or fibers woven or wound together with a reinforcing layer to resist pressure within the tube . In order to protect the internal layers of rubber hose, outside in the enhancement layer there is a layer of synthetic rubber protective layer . They are called the inner layer , reinforcing layer and the outer layer 2 , the working pressureSelection of the need to ensure the hose and Hydraulic tube fittings  are the maximum recommended working pressure greater than or equal to the maximum working pressure of the system . System pressure or pulse peak pressure must be less than or equal to the maximum working pressure of the hose assembly .the test pressureTest is usually used water or other suitable medium at ambient temperature. Hose assembly should be 2 times the working pressure dwell 30-60 seconds no leakage, no pressure drop , in order that the Assembly passes the pressure test . This test is performed according to standard ISO 1402 . burst pressureThis means that the resulting pressure of the hose rupture should be given at least 4 times the working pressure ( present, most enterprises are 4 times the pressure hose to the design and production ) , but the product in the sample hose burst pressure value only as production testing purposes, not as a basis for selection hose .fluid compatibilityHose assembly must be in contact with the medium has good chemical compatibility , or may cause the hydraulic system is not working properly or hose premature aging and failure  the temperature rangeTo avoid affect the performance of rubber hoses , media, and the surrounding environment temperature should not exceed the temperature range of the hose to adapt itself , otherwise it would be premature aging of the hose , resulting in leakage. hose bend radiusHose hose bend radius is calibrated at its maximum working pressure for continuous operation can achieve the minimum bend radius , this bending mode of operation , should not affect the performance of the hose .Bending radius of the hose does not mean it can not be measured softness .The minimum bend radius of the hose bent to use , it will seriously affect the strength of the hose , causing the hose failure . Hose and hose connector transitional minimum straight length equal to or greater than 1.5 times the outer diameter of the hose . hose and fittings for storageTo ensure that the hose used in the period , should establish a proper system to be stored on the hose control . In German-speaking countries , hose and hose assembly must be stored in accordance with the standard DIN 20066:2002-10 to execute. Relevant parts are summarized as follows : Assemble hose assembly must be used within four years ( from date of manufacture hose timer ) . Hose assembly from the date of production time, which shall not exceed the useful life of six years , in these six years, the storage time should not exceed 2 years.