Precautions for hydraulic system pollution control and filter selection

Precautions for hydraulic system pollution control and filter selection

More than 80% of hydraulic system failures are caused by oil pollution. Controlling oil pollution can prolong the service life of hydraulic components and hydraulic oil and ensure the continuous and reliable operation of the system.

There are two main measures to control the pollution of hydraulic system oil: one is to prevent pollutants from entering the system, and the other is to filter and purify the hydraulic system oil.

One to prevent pollutants from entering the system

It prevents illness from entering the mouth considerably. Design a well-sealed fuel tank, select an air filter with good filtering performance, pay attention to removing impurities in components and pipelines when installing the system, use a good dust-proof seal on the cylinder, and strictly filter the new oil injected into the system to prevent pollutants from entering the system Measures.

2. Filtration and purification of hydraulic system oil

The suction filter, the pipeline filter and the return oil filter complete the oil filtration and purification. The following points should be paid attention to when selecting the filter:

1 The suction port filter should be a filter with low filtration accuracy and large flow capacity. The suction filter with poor flow capacity is likely to cause cavitation. The suction filter is used to block large particles of pollutants from entering the hydraulic pump. To prevent suspension in the oil The air bubbles enter the system. Generally, do not use suction filters for plunger pumps, the reason is omitted.

2 The pipeline filter is generally installed upstream of the more important components, and the filtering accuracy should be higher than the matching clearance of the component friction pair. The servo system pipeline filter should not use the bypass check valve, and the pressure resistance of the filter element should be high.

3 The pressure resistance of the return oil filter is low. In a system with a thicker piston rod, the flow through the filter is greater than the pump flow. When selecting the filter, pay attention to the flow rate of the filter. product.

4 Selection of filter flow rate: Appropriately increasing the filter flow rate will extend the filter life.

5 Selection of filter accuracy: When selecting the main filter of the system, such as the accuracy of the pipeline filter, the filter should be able to remove the particles of the dynamic oil film thickness of the hydraulic component movement, because once the particles of this size enter the movement pair In the gap, the surface of the component will be worn and the gap will increase, so that larger particles enter the gap, causing further wear and tear, resulting in a "chain reaction" of severe wear. The "chain reaction" is a bit like a pyramid scheme. , Can quickly lead to component failure.

The above-mentioned hydraulic system pollution control is mainly aimed at solid particles. The pollution sources of the hydraulic system also include water and air, and the hazards cannot be ignored. . . . . . In short, the entire process of hydraulic system design, manufacture, installation, use and maintenance must pay attention to the control of hydraulic system pollution.

Tips:

1 The visual limit of human eyes is 40μm, and the wear of hydraulic components is generally smaller than 40μm particles, which are invisible to the naked eye.

2 Definition of filtration ratio: ß x = the number of particles larger than the size xμm in the upstream / the number of particles larger than the size xμm in the downstream

x: is the size of the particles, in μm

In the hydraulic servo system, a filter with a filtration ratio β3 ≥200 is generally required.

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