(1) The inner and outer layers of the high pressure hose wall are oil-resistant rubber, and the middle is (2 to 4 layers) interspersed braided steel wire or winding wire. The poor quality of the hose will show: uneven thickness of the hose wall; steel wire braided too tight, too loose or too few layers of steel wire; poor rubber seal the outer layer caused by wire corrosion; poor sealing of the inner layer of rubber and high-pressure oil into the steel wire Layer; adhesive layer and steel layer adhesion lack.
(2) Improper selection of crimping pressure and crimping speed when assembling hoses and joints, or unreasonable selection of structure, material, and size of the joints can all lead to over-tightening or excessive looseness of hoses and joints, leading to early damage at joints. During assembly, if the buckle pressure is too small, that is, if the pressure between the joint and the hose is too loose, the hose may come out of the joint at the initial stage of operation under the effect of the oil pressure; when the hose and the joint are assembled, if the buckle pressure is used to overcome Fast, easy to form internal rubber damage and wire layer fracture, so that the hose in the application of premature damage. In addition, unreasonable joint design, poor processing quality, will also cause damage to the internal plastic; if the joint material is not properly selected, in the buckle process easily deformed, thus affecting the buckle quality, shorten the life of the hose.
Improper use Under the premise of quality assurance, if used improperly, the service life of hoses will be greatly shortened. In practice, most high-pressure hoses were damaged due to improper use.
(1) Frequent, violent pressure shocks. High-pressure hoses appear to burst. Normally, they are not caused by too much static pressure, but are related to the violent level and number of pressure shocks. When the construction machinery is in operation, the sudden increase or decrease of the oil pressure in the oil pipe will repeatedly occur, which will cause frequent pressure impacts on the oil pipe, resulting in increased damage to the oil seals of various departments, foaming and cracking of the hose, and loosening of the pipe joints. Leakage phenomenon. Therefore, when operating, the valve stem must not be pulled too hard and must be flat.
(2) hose selection, device is not reasonable. When changing the high-pressure hose, the length of the selected hose, the number of layers of the steel wire, the shape and size of the joint must be reasonable, and the bending level of the hose should be minimized; when tightening the joint nut, the hose should not be distorted, excessively bent and Twisting will greatly reduce the service life of the hose; for some parts that are susceptible to friction, protective measures should be taken to prevent the hose from bursting due to wear.