How are bubbles in hydraulic oil produced? How to solve it?
December 02, 2021
The hydraulic oil is the hydraulic medium used in the hydraulic system using the hydraulic pressure energy, which plays the role of energy transmission, anti-wear, system lubrication, anti-corrosion, anti-rust, and cooling in the hydraulic system. Some friends asked about the increase of foam in the use of hydraulic oil, and asked what happened? We must first look for the reason, not blindly add anti-foaming agents, we must prescribe the right medicine!
The usual causes of bubbles in hydraulic oil are as follows: 1. It is likely that the hydraulic oil is improperly stored and mixed with water; 2. It may be related to the mixed use of hydraulic oils of different brands; 3. Leakage of seals, joints, and pipelines; 4. The amount of hydraulic oil is seriously insufficient 5. It may be related to the design of the fuel tank, such as a small fuel tank volume, insufficient spacing between the oil suction pipe and the oil return pipe, etc. 6. It is also possible that the return oil splashes or is severely agitated, and foam is formed; 7. It may be caused by oil pump leaks, etc. Solution: 1. Generally, anti-foam additives are added to the oil. Currently, the widely used Anti-foaming Agent is simethicone. The effect of adding anti-foaming agent to hydraulic oil can not prevent the foaming tendency of lubricating oil, but can only reduce the stability of foam adsorption film and shorten the existence time of foam. 2. Use silicone oil defoamer Silicone oil has a good defoaming effect, at the same time, it has a small dosage, low volatility, good oxidation resistance and high temperature resistance. However, silicone oil is insoluble in lubricating oil. The emulsion of silicone oil and lubricating oil is an unstable system, which is easy to layer and lose its defoaming effect. The defoaming effect of silicone oil and its durability are determined by the degree of dispersion in the lubricating oil. Generally speaking, only when silicone oil particles are smaller than 100 µm can they show defoaming effect, and a few microns are more stable. In order to improve the dispersion stability of silicone oil, the silicone oil can be formulated into a solution and added dropwise to the lubricating oil under high-speed stirring (3000-6000r/min). It can also be treated with colloid milling to make the particle size of the silicone oil reach 1-3 µm, even Below 0.5µm. 3. A 60 mesh metal diagonal net can be installed at the bottom of the fuel tank to defoam. 4. If you need to completely eliminate the foam, use a vacuum oil filter to filter the hydraulic oil.
