The reason for the bubbling on the outer surface of the hose is that the quality of the hose is not

1 fault of outer layer
(1) cracks in the exterior of the hose
The main reason for the crack in the exterior of the hose is the bending of the hose in the cold environment.
(2) bubbling on the outer surface of the hose
The reason for the bubbling on the outer surface of the hose is that the quality of the hose is not qualified, or the improper use of the hose is used.
(3) the hose is not broken but a large amount of oil is permeated
The hose was oozing oil but no rupture was found. The reason is that the inner glue is eroded and scratched through the high-pressure liquid flow in the hose until the large area leaks out the steel wire layer, resulting in a lot of oil leakage.
(4) the outer rubber layer of the hose is seriously deteriorated and the surface appears microcrack which is the natural aging performance of the hose. Because of aging and deterioration, the outer layer is continuously oxidized to make the surface covered with a layer of ozone, thickening with time. When the hose is in use, it will produce tiny cracks if it is slightly curved. In this case, the hose should be replaced.
2 internal glue layer failure
(1) the hose in the hose is hard and crack: the main reason is that the rubber products are flexible and plastic due to the addition of plasticizers. But the overheated hose will overflow the plasticizer.
(2) hose tube serious deterioration, obviously swollen: hose tube causes serious deterioration, obvious swell is oil hose rubber material and hydraulic system is not compatible, hose by chemical and metamorphism.
3 is shown in the failure of the strengthening layer
(1) the rupture of the hose, the rupture of the rusty hose of the braided steel wire near the crack, the inspection of the outer rubber layer, and the rust of the braided steel wire near the crack. This is mainly due to the effect of wet or corrosive substances on the layer, which weakens the strength of the hose and causes high pressure to rupture.
(2) the reinforcing layer of the hose is not rusty, but the irregular broken wire appears in the reinforced layer.
When the hose ruptured and the outer rubber layer was removed, no rust was found in the reinforcement layer, but the irregular wire breaking in the length direction of the strengthened layer was mainly caused by the high frequency impact force of the hose.
4 malfunction at the rupture
(1) the hose is broken at one or more places, the cracks are neatly, and the other parts are kept good.
The main reason for this phenomenon is that the system pressure is too high, and the pressure resistance of the hose is exceeded.
(2) torsion at the rupture of the hose
The cause of this phenomenon is that the hose is caused by excessive torsion during the installation or use of the hose.
Summary, through the above analysis, the following matters should be paid attention to in the use of hydraulic hose in the future:
The hose arrangement should avoid the heat source as far as possible, away from the performance of the engine exhaust pipe. When necessary, a casing or protective screen can be used to prevent the hose from being heated and deteriorated.
(2) hoses must be crossed or may be rubbed against the mechanical surfaces when working. Apply hose clamps or springs to protect the outer layer of rubber hoses.
When the hose must be bent, the bending radius should not be too small, and it should be greater than 9 times the outer diameter. The joint of the hose and the joint should have a section of a straight line that is 2 times larger than the outer diameter of the tube.
(4) hose installation should avoid being in a tight state. Even if there is no relative movement between ends of the hose, the hose should be kept loose. The flexible hose will expand and decrease in strength under pressure.
Do not twist the hose during the installation process. If the hose is slightly torsional, it may reduce its strength and release the joint. When assembling, the connector should be tightened on the hose instead of fastening the hose on the joint.
The hose in key parts such as configuration, suggestions for their regular inspection or replacement.