Causes of oil leakage in hydraulic tubes

There are many types of pipelines used in hydraulic systems. Depending on the working pressure and installation location of the hydraulic system, steel pipes, copper pipes, rubber pipes, nylon pipes and plastic pipes are used. Once these pipelines are damaged and leak oil, it will pollute the environment and affect the normal function of the system, and even endanger safety.
When repairing or replacing hydraulic pipelines, if inferior pipelines are installed in the hydraulic system, oil leakage will occur within a short period of time due to their low pressure-bearing capacity and short service life. The main symptoms of poor quality of hard oil pipes are uneven pipe wall thickness, which reduces the load-bearing capacity; the main symptoms of inferior hoses are poor rubber quality, insufficient steel wire layer tension, and uneven weaving, which results in insufficient load-bearing capacity. Under the impact of pressure oil, It is easy to cause pipeline damage and oil leakage.
Causes of oil leakage in hydraulic tubes
1. Poor pipeline bending
During the process of assembling hard pipes, the pipes should be bent according to the specified bending radius. Otherwise, different bending internal stresses will be generated in the pipes, and leakage will gradually occur under the action of oil pressure. If the bending radius of the hard pipe is too small, the outer pipe wall of the pipe will become thinner and the inner pipe wall will have wrinkles, which will cause the pipe to have great internal stress at the bend and greatly weaken the strength. When strong vibration or high pressure impact occurs, the pipe will collapse. The road is prone to transverse cracks and oil leakage; if there is a large ovality in the bend of the hard pipe, longitudinal cracks are prone to occur and oil leakage occurs when the oil pressure in the pipe pulsates.
When installing the hose, if the bending radius does not meet the requirements or the hose is twisted, it will cause damage to the hose and cause oil leakage.
2. The installation and fixation of pipelines does not meet the requirements.
Common improper installation and fixation include:
(1) When installing oil pipes, forcibly assemble them regardless of the length, angle, and threads of the pipes, which will deform the pipes and generate installation stress. At the same time, it is easy to damage the pipes, resulting in a decrease in its strength;
(2) Do not pay attention to the fixation when installing the oil pipe. When the bolts are tightened, the pipe will rotate together, causing the pipe to twist or collide with other parts and cause friction, shortening the service life of the pipe;
(3) The pipeline clamps are sometimes too loose, which increases the friction and vibration between the pipeline and the clamps; sometimes they are too tight, causing the pipeline surface (especially the aluminum pipe) to be pinched and deformed; these situations will cause the pipeline to be damaged and cause damage. oil leak;
(4) The tightening torque of pipeline joints seriously exceeds the regulations, causing the bell mouth of the joint to break, causing the thread to be strained and tripped, resulting in serious oil leakage accidents.
3 Hydraulic pipeline fatigue damage or aging
Observation and analysis of a large number of hard hydraulic pipeline fractures show that the rupture of hard pipes is a kind of fatigue damage, so there must be alternating loads on the pipelines. When the hydraulic system is working, the hydraulic pipeline has to withstand high pressure. Coupled with the alternating stress caused by unstable pressure, vibration stress caused by equipment vibration, assembly stress, etc., the hard pipe will be exposed to material defects. , corrosion points or damage will cause stress concentration, and the pipeline will suffer fatigue damage and fracture, resulting in oil leakage. For rubber pipelines, they will age, harden and crack due to high temperature, high pressure, severe bending and distortion, and finally the oil pipe will burst and leak oil. Long Ben hydraulic steel pipe
4 Hydraulic oil contamination and pipeline surface contamination
When the hydraulic oil is contaminated, the oil pipe will be worn and corroded, accelerating the rupture of the pipe and causing oil leakage. Moreover, this damage is not easy to detect, making the harm more serious.
Since hydraulic systems are easily contaminated, hydraulic oil containing solid contaminants is similar to the abrasives used to grind metal processing surfaces, which increases the friction between the oil and the inner wall of the pipeline. Moreover, usually the hardness of solid pollutant particles is much higher than the hardness of the inner wall material of the conduit, which accelerates the wear of the inner wall of the conduit and even scratches the inner wall. Especially when the flow rate of the liquid is high and unstable (fast flow rate and large pressure pulsation), the material on the inner wall of the conduit will be impacted and peeled off.
When the hydraulic oil contains water, it will cause the hydraulic oil to form an emulsion, which will reduce the lubrication and anti-corrosion effects of the hydraulic oil and accelerate the wear and corrosion of the inner wall of the pipeline. When the hydraulic oil contains a large number of bubbles, the bubbles are compressed in the high-pressure pipeline, and the surrounding oil flows to the space originally occupied by the bubbles at high speed, causing a strong hydraulic impact. Under the impact of the high-pressure liquid mixture, the inner wall of the pipeline is affected by Corroded and peeled off. All of the above situations will eventually cause the pipeline to rupture and cause oil leakage.
In addition, the outer surface of the pipeline is often stained with moisture, sludge and dust. If the protective layer is damaged, corrosion will easily occur, leading to a decrease in strength, until explosive oil occurs in places with high temperature, high pressure, severe bending and distortion.