How to prevent water, air and solid impurities from entering hydraulic oil in daily maintenance of hydraulic pumps

1. Choose the right hydraulic oil

Hydraulic oil plays the role of transmitting pressure, lubricating, cooling and sealing in hydraulic pump. Improper selection of hydraulic oil is the main reason for early failure and durability decline of hydraulic pump. The hydraulic oil should be selected according to the grade specified in the random "Instruction for Use". The hydraulic oil of different grades cannot be mixed to prevent the hydraulic oil from chemically reacting and changing its performance. Dark brown, milky white, odorous hydraulic oil is deteriorating oil and cannot be used.

2. Prevent solid impurities from mixing into the hydraulic pump

When refueling, the staff must pay attention to use clean work clothes and gloves when refueling to prevent solid impurities and fibers from falling into the oil. The filling of hydraulic oil must be filtered by the filter trolley. In order to ensure the cleanliness of the oil, the solid trolley should be cleaned regularly. At the same time, in order to increase the speed of refueling, the filter from the fuel tank cannot be removed.

During maintenance, the oil passages of the Rexroth hydraulic pump may be exposed when removing the hydraulic oil tank inspection hole, filter cover, fuel cap, hydraulic oil and other parts, so be sure to avoid dust. When disassembling these parts, be sure to clean them before opening them. For example: when removing the fuel cap of the hydraulic oil tank, first remove the soil around the fuel tank cap, and after the fuel tank cap is loosened, remove the impurities remaining in the joint part, and then open the fuel tank cap. Hydraulic hoses and components should be carefully cleaned, and then air-dried before assembly. Do not forget to clean the filter when changing the oil. Before installing the filter element, carefully check whether there is any dirt in the filter element housing. If there is, use a special material to wipe it, and then install it after wiping it clean.

3. Cleaning of hydraulic oil tank

Drain the deteriorated hydraulic oil, open the fuel tank cover, someone will enter the fuel tank with clean flour and make dough, wipe all corners of the fuel tank with the dough, then seal the fuel tank and add hydraulic oil.

4. Prevent air from invading the hydraulic pump

At normal temperature, the hydraulic oil contains 6~8% air. When the pressure is reduced, the air will be separated from the oil to form air bubbles. When these air bubbles burst, the hydraulic components will be "cavitated". This phenomenon is exacerbated when large amounts of air enter the hydraulic oil. The compressibility of hydraulic oil increases, the operation will be unstable, and the working efficiency will decrease.

In addition, the entry of air will also oxidize the hydraulic oil, causing the oil to deteriorate. To prevent the intrusion of air, you need to do the following two things:

①Maintenance and oil change must be carried out in accordance with the steps in the "Instruction Manual" to remove the air in the hydraulic pump.

②The oil suction line of the hydraulic pump must be well sealed and the oil surface cannot be exposed.

5. Prevent water from invading the hydraulic pump

If the oil contains too much water, the hydraulic components are likely to be corroded, the oil may deteriorate, the strength of the lubricating film may be reduced, and the mechanical wear will be aggravated. Pay attention to prevent moisture intrusion during maintenance. In addition, pay attention to tightening the lid of the oil storage tank when it is not in use. It is best to put it upside down. Oils with high water content must be filtered several times before they can be used, and the drying filter paper should be replaced once for each filtration. After filtering, you can drop the oil on the hot iron plate, there is no steam and immediately burn to prove that the filter is clean, so that you can refill.

6. Maintain a suitable oil temperature

The working temperature of the hydraulic pump is generally controlled between 30 and 80 °C. If the oil temperature of the hydraulic pump is too high, it will cause: the viscosity of the oil is reduced, which is easy to cause leakage and reduce the efficiency; the strength of the lubricating oil film is reduced, which accelerates the wear of the machine; Hose premature aging, etc.