Created on:2021-12-21 13:40

Flushing of hydraulic system

Flushing of hydraulic system

(1) First cleaning. The first cleaning of the hydraulic system is carried out after the pre installation (trial assembly of pipes), all the pipes are removed and disassembled.

The first cleaning shall ensure that a large number of obvious and possible cleaned metal burrs, powder, sand dust, paint, oxide skin, oil stains, cotton yarn, rubber particles and other dirt are carefully cleaned. Otherwise, the first installation of the hydraulic system is not allowed.

The first cleaning time depends on the size of the hydraulic system, the required filtration accuracy and the pollution degree of the hydraulic system. When the predetermined cleaning time is reached, it can be determined whether the cleaning work is completed according to the type and quantity of impurities filtered in the filter screen.

The first cleaning is mainly for pickling pipeline and cleaning oil tank and various components. There are several methods for pipeline pickling.

1) Degreasing and initial washing. Remove the burr on the oil pipe, degrease (Degrease) with sodium hydroxide, sodium sulfate, etc., and then clean with warm water.

2) Pickling. Soak and wash in 20% ~ 30% dilute hydrochloric acid or 10% ~ 20% dilute sulfuric acid solution for 30 ~ 40min (the solution temperature is 40 ~ 60 ℃), and then wash with warm water. The cleaning pipe must be vibrated or knocked to cause the oxide scale to fall off.

3) Neutralization. Soak and wash in 10% caustic soda (soda) solution for 15min (the solution temperature is 30 ~ 40 ℃), and then wash with steam or warm water.

4) Antirust treatment. After drying in clean and dry air, apply antirust oil.

After confirming that the cleaning is qualified, the first installation can be carried out.

(2) Second cleaning. The second cleaning of the hydraulic system is the internal circulation cleaning of the system after the first installation of the cleaning circuit.

The purpose of the second cleaning is to clean the residual dirt after the first installation, such as sealing fragments, cleaning oil of different quality, antirust oil, sand particles washed out from the inside of the casting and powder from metal running in, and then conduct the second installation to form a formal system, so as to ensure the smooth formal adjustment, commissioning and normal operation. For the hydraulic equipment just purchased from the manufacturer, if it has been cleaned as required, only the parts processed and installed on site can be cleaned.

The steps and methods of the second cleaning are as follows.

1) Cleaning preparation.

① Preparation of cleaning oil. The cleaning oil can be the working oil or test oil of the hydraulic system of the cleaned mechanical equipment. Kerosene, gasoline, alcohol or steam are not allowed to be used as cleaning media to avoid corrosion of hydraulic components, pipelines and oil tanks. The amount of cleaning oil is usually 60% ~ 70% of the oil in the oil tank.

② Preparation of oil filter. A temporary oil return filter shall be connected to the cleaning pipeline. Generally, oil filters with mesh accuracy of 80 mesh and 150 mesh are selected for use after the initial stage and later stage of cleaning, so as to filter out impurities and dirt in the system and keep the oil clean.

③ Clean the oil tank. Before cleaning the hydraulic system, clean the oil tank first. After cleaning, wipe the inner surface of the oil tank with silk cloth or vinyl resin sponge before adding cleaning oil. It is not allowed to wipe the oil tank with cotton cloth or fiber. Some enterprises use dough to clean the oil tank, which can also get an ideal cleaning effect.

④ Preparation of heating device. Cleaning oil generally has corrosion ability to non oil resistant rubber. If it is heated to 50 ~ 80 ℃, the rubber sludge and other sundries in the pipeline can be easily removed. Therefore, the oil shall be heated and cooled for about 12h respectively during cleaning, so the heating device shall be prepared.

Home    Article    Flushing of hydraulic system