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Causes and Prophylactic Measures of Hydraulic Cylinder Cavitation
There are some honeycomb cavity on cylinder inner wall and piston and piston rod surface of hydraulic cylinder,this is the result of cavitation.Cavitation can cause rough on the cooperation surface of the cylinder and piston rod, lead hydraulic cylinder inside leaking,reducing working speed.The The combination of cavitation and other forms corrosion will accelerate the corrosion of main parts of the hydraulic cylinder and thus seriously affect the normal use of machinery.
1.Factors of Cavitation
When the hydraulic cylinder surface parts and hydraulic oil make relative movement, dissolved gas in the hydraulic oil easy to precipitate and formation of air bubbles.These bubbles will break down after flow to high pressure area,micro fluidic and impact force with high temperature and high pressure creating in this instant, repeated acts on the surface of hydraulic cylinder parts,make the surface of parts produce cavitation.The cause of cavitation is related with the hydraulic system structure, the hydraulic cylinder parts material, hydraulic oil quality, manufacturing and maintenance.
(1)Hydraulic system structure
If the pipeline of hydraulic system, the access of control valve are too narrow and bends are too much, will lead the hydraulic oil temperature rise, increase the impact, then easy to produce bubbles in the hydraulic oil, causing the cavitation of the hydraulic cylinder.
(2)Hydraulic cylinder parts material
If the material of the hydraulic cylinder has good strength, toughness and corrosion resistance,its ability to better anti cavitation; otherwise prone to cavitation.Another influence is the uniformity of the material organization,more uneven material organization,its weaknesses and low resistance to corrosion areas will be easy to generate cavitation.
(3)Hydraulic oil quality
The quality of the hydraulic oil is an important factor for cavitation . Hydraulic oil will shock with valves and piping inevitably at work, if the hydraulic oil resistant foam is poor, it is easy to produce foam, and causing cavitation on the hydraulic cylinder and other parts . If the frequency change of hydraulic oil pressure is too fast, it will promote the formation of bubbles,and speed up the bubbles burst. For example, the oil in and out area of the hydraulic cylinder, due to pressure changes in the frequency of relatively high,the degree of cavitation is relatively higher than other parts.
(4)Manufacturing and maintenance
The cavitation caused by quality of assembly and repair for hydraulic cylinder is also can not be discounted.If the hydraulic system is not fully exhaust assembly or repair,the presence of gas under the action of high temperature and high pressure will cause cavitation.
2.Measures to Prevent Cavitation
Although the hydraulic cylinder cavitation impact factors are so many , but if take active preventive measures,cavitation can be avoided.Its measures are as follows:
(1)select a qualified hydraulic oil
Better quality and suitable grade of hydraulic oil can effectively prevent the bubbles generated during operation.Optional hydraulic oil shall comply with the relevant technical requirements of the premise , referring to the region's temperature,and raise according to the dipstick standard.
Furthermore, keep the hydraulic system clean. You should always check the oil character, oil level and oil color, if found foam or becomes milk white,indicating hydraulic oil has been mixed with the air,you should carefully check the air source and and replaced with new oil. If you use a high water-based hydraulic oil,you should configure the high-mounted hydraulic tank to increase pressure of the pump inlet, prevent hydraulic cylinder cavitation.
(2)Choose the appropriate hydraulic oil additive
Choose the appropriate hydraulic oil additive what can effectively suppress the phenomenon of turbidity or hydration,prevent foaming, stable quality hydraulic oil, make hydraulic oil maintain normal performance for a long time.
(3) Prevent high temperature of the oil,reduce hydraulic shock
The rational allocation of hydraulic oil cooling device can prevent hydraulic oil too high. If there is phenomenon of high temperature oil in your work,you should find out the reasons and solve immediately to eliminate the condition of hydraulic oil bubbles.In addition,in the process of hydraulic system,frequent increase the engine throttle is forbidden,stable manipulation can mitigate the impact of hydraulic oil to the hydraulic components.
(4)Correct assembly and repair hydraulic cylinders
The hydraulic cylinder block, piston and other major parts should be assembled and repair according to the lower limit of dimensional tolerances,which can very well reduce the occurrence of cavitation . If the hydraulic cylinder parts cavitation has appeared,the only method is using optical polishing sandpaper to remove cavitation pitting and surface fouling,not with ordinary fine sandpaper to polish treatment .
After maintenance,the cylinder should run under no-load and stable condition,make the hydraulic oil gain fully recyclable. If the hydraulic system mix with air,artificial exhaust canbe done:slow release the not of the cylinder oil inlet or return pipe,when the bubble is completely discharged tighten the nut.
More knowledge about the cylinder,contact us.Hei Yan is professional for the pipe fittings equipment such as hot elbow machine,pipe bending machine,hyarulic press machine and the ancillary facility,accessories.