Views:25 Author:Site Editor Publish Time: 2019-09-29 Origin:Site
The reasons for hose assemblies failures are as below:
1. The hydraulic (emulsion) system pressure source adopts three-piston pump or five-piston pump. The rated pressure is high, the flow rate is large, the pressure pulsation is large, and the components of the pipeline are easily fatigue damaged.
Especially the main liquid supply pipeline works for a long time under the high impulse pressure state. The weak connection failure of the high-pressure hose, such as the sealing ring, fittings, adapters, etc., is much higher than the high-pressure hose supporter. Because of High-pressure hoses only withstand high pressure when the bracket is in motion, the action time is short, and the mechanism of failure is different.
2. The emulsion medium has high density and poor corrosion resistance.
In particular, the water quality and alkalinity of different mining areas vary greatly. The management in use is not strict. The downhole emulsion often does not reach the specified oil-water ratio. Rubber has been immersed in this medium for a long time, and it will inevitably deteriorate, harden and age.
3. Due to the use characteristics of underground equipment, the cleanliness of the medium is low, and the medium contains more gas.
(1) On the one hand, cavitation is highly prone to occur, and when cavitation occurs, the pressure peak can exceed 1 GPa;
(2) On the other hand, high-speed and the large-flow emulsion is wrapped with fine impurities, impacting the inner the surface of the hose and the joint assembly, which will plow a groove and cause wire erosion.
The damage of the rubber layer in the high-pressure hose accelerates the corrosion of the steel mesh of the hose and reduces the compressive strength of the high-pressure hose. The pressure wave has a strong impact on the high-pressure hose assembly and the joint assembly, and causes breakage (breaking) of the dangerous section of the high pressure hose assembly and the joint assembly.
4, coal mine production environment has dust, humidity, alkaline water.
The vibrating hose line rubs against the environmental object, causing abrasion to the hose surface rubber, anti-corrosion layer on the fittings is detached, thereby promoting the damage process.
5. The factories producing high-pressure hose assemblies and intermediate joint components are mostly small and medium-sized enterprises, subject to technical, equipment, capital and other conditions.
Some do not even process according to the technical requirements of the drawings. The high-pressure hose assembly and pipeline accessories do not meet the technical requirements, the product quality is uneven, the strength is low, the life is short, and the pollution is serious, which poses hidden dangers for sudden safety accidents.
6, the design layout is not reasonable
Under normal conditions, the high-pressure hose is mainly subjected to internal pressure and a certain (bending) external force. The incorrect arrangement makes the high-pressure hose long-term in additional force (tension, torsion) and reduces the service life of the high-pressure hose assembly.
7, the failure of hose components for long life use
Due to the inability to inspect and accurately determine whether the high-pressure hose and components fail or reach the service life, there are a large number of components that are used for longer life, these high-pressure hoses are often prone to failure during use, resulting in increased failure rates.