- Dec 12, 2018 -
Common faults and causes of high pressure hose
1 Failure of the outer layer
(1) Cracks appear on the outside of the hose
The main cause of cracks in the appearance of the hose is that the hose is bent in a 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 unqualified or improperly used during work.
(3) The hose is not broken but a lot of oil seepage
The hose leaked a lot of oil but no crack was found. The reason was that when the hose passed through the high-pressure liquid flow, the inner rubber was washed away and scratched until a large area leaked out of the steel wire layer, causing a large amount of oil leakage.
(4) The outer rubber layer of the hose is seriously deteriorated, and the surface is slightly cracked. This is a natural aging performance of the hose. Due to aging deterioration, the outer layer is continuously oxidized to cover the surface with a layer of ozone, which is thickened with time. The hose is slightly bent when used, and micro cracks are generated. In this case, the hose should be replaced.
2 Internal rubber layer failure
(1) The inner rubber layer of the hose is hard and cracked: the main reason is that the rubber is flexible and plasticizable due to the addition of plasticizer. However, if the hose is overheated, the plasticizer will overflow.
(2) The inner rubber layer of the hose is seriously deteriorated and obviously swells: the inner rubber layer of the hose is seriously deteriorated. The reason for the obvious swelling is that the inner rubber material of the hose is incompatible with the oil used in the hydraulic system, and the hose is chemically deteriorated. .
3 performance failure in the reinforcement layer
(1) The hose is broken, and the rusted hose of the braided steel wire near the break is broken. The outer rubber layer is peeled off and the woven wire near the crack is found to be rusty. This is mainly due to the fact that the layer is exposed to moisture or corrosive substances, which weakens the strength of the hose and causes cracking at high pressure.
(2) The hose reinforcement layer is not rusted, but the reinforcement layer is irregularly broken.
The hose was broken, and the outer layer was not peeled off, but the reinforcing layer was rusted, but the broken layer appeared irregularly in the longitudinal direction. The main reason was that the hose was subjected to high-frequency impact.
4 Faults manifested at the rupture
(1) One or more hoses are broken, the gaps are neat, and the other parts are well maintained.
The main reason for this phenomenon is that the system pressure is too high, exceeding the pressure resistance of the hose.
(2) Torsion at the rupture of the hose
This phenomenon occurs because the hose is excessively twisted during installation or use.
In summary, through the above analysis, the following should be noted when using hydraulic hoses in the future:
1 Hose layout should avoid heat source and keep away from the performance of engine exhaust pipe. If necessary, a device such as a casing or a protective screen may be used to prevent the hose from being deteriorated by heat.
2 Where the hose must be crossed or where it may rub against the mechanical surface, use a protective device such as a hose clamp or spring to prevent damage to the outer layer of the hose.
3 When the hose must be bent, the bending radius should not be too small and should be greater than 9 times the outer diameter. The hose and joint joint shall have a straight section that is more than twice the outer diameter of the pipe.
4 When installing the hose, avoid tightening. Even if there is no relative movement at both ends of the hose, keep the hose slack. The tensioned hose will expand under pressure and the strength will decrease.
5 Do not twist the hose during installation. A slight twist of the hose may reduce the strength and loosen the joint. The fitting should be tightened onto the hose instead of tightening the hose to the fitting.
6 If the hose is placed on a critical component, it is recommended to periodically check or replace it.
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