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Engineering machinery hydraulic valve cavitation corrosion mainly related to these! |
| Author：FA Date：8/24/2018 8:04:41 PM |
Engineering machinery hydraulic valve cavitation corrosion mainly related to these! Analysis of the causes of cavitation of hydraulic valve from the formation of cavitation of hydraulic valve, not considering the structural factors of hydraulic valve, the production of cavitation is mainly related to the bubble of hydraulic oil and frequent movements of hydraulic valve. (1) frequent action of hydraulic valve. In the hydraulic system, all kinds of hydraulic valves control the flow pressure, flow rate and flow direction by changing the size of the valve hole and the flow area and pressure difference to meet the requirements of force (or torque), speed and direction required by the actuator. The frequent action of hydraulic valve makes the change frequency of oil pressure too fast and too high, which will directly cause the formation of air bubbles and accelerate the burst speed of air bubbles. Tests have shown that the rate of cavitation increases where pressure changes frequently. (2) the hydraulic oil produces air bubbles. In hydraulic transmission, hydraulic oil always contains a certain amount of air. Air can be dissolved in hydraulic oil or mixed in the form of bubbles. For mineral hydraulic oil, the dissolved air is 6% ~ 12% at room temperature. The critical pressure of air separation into bubbles in oil is related to oil type, oil and air solubility. To prevent the hydraulic oil from bubble, can slow down the occurrence of cavitation. In addition to reasonable design, scientific material selection and improvement of processing technology, reasonable use of hydraulic equipment is of vital importance to reduce hydraulic broad cavitation. In the process of use to reduce the hydraulic valve cavitation, mainly to reduce as far as possible the hydraulic oil bubble and the correct operation of the hydraulic valve. (1) operate the hydraulic valve correctly. The frequency of oil pressure change directly affects the rate of bubble formation and fracture, the part where the pressure change frequency is high and the rate of gas erosion is fast. Therefore, when operating hydraulic valves should be stable, the process should not be too fast, too strong, to reduce hydraulic impact, thereby reducing the occurrence of cavitation. (2) reduce air bubbles produced by hydraulic oil. In order to reduce the air bubble produced by hydraulic oil, the following important considerations are taken into account: 1) prevent the hydraulic oil temperature from being too high. The cooling system should be maintained in a timely manner to keep the temperature of the cooling system within the proper range to reduce the energy released when the bubble bursts. 2) reasonable selection and use of hydraulic oil. The hydraulic system has strict requirements on the variety, brand and anti-foam of hydraulic oil, and should be added or replaced as required. If the oil has poor foaming resistance and is prone to vaporization and foam formation, cavitation may occur. 3) vent after maintenance and oil change. If the hydraulic system is not fully vented after maintenance and oil change, there will be gas in the system, which will easily produce cavitation under the action of high temperature and high pressure. Therefore, after maintenance and oil change, the hydraulic system should exclude the air in the system according to the random "operating instructions". 4) prevent the "empty" phenomenon of hydraulic pump. Hydraulic pump "suction empty" refers to the pump inhaled by the oil mixed with air (not dissolved air in the oil). The air mixed with the oil is usually suspended in the oil in the form of small bubbles. These bubbles will flow with the oil continuously, which will increase the production of gas erosion. For this reason, the hydraulic pump suction pipe joint shall be strictly sealed. The oil in the oil tank should be filled according to the regulations; The oil suction pipe must be immersed into the designated position of the oil tank, which can effectively prevent the hydraulic pump "empty" phenomenon. In a word, the above on the basis of analyzing the formation process of the hydraulic valve cavitation, think without considering hydraulic valve structure factors under the premise of the generation of cavitation and hydraulic oil creating the frequent movement of bubbles and hydraulic valve, and thus put forward to reduce hydraulic valve cavitation in addition to the reasonable design, scientific selection, improving processing technology measures, such as the rational use of hydraulic equipment is very important to reduce hydraulic valve cavitation. In the process of use to reduce the hydraulic valve cavitation, mainly to reduce as far as possible the hydraulic oil bubble and the correct operation of the hydraulic valve. |
