Hydraulic lifter jacks rely heavily on the hydraulic oil used to perform effectively. When choosing a hydraulic oil, there are several factors to consider:
Appropriate viscosity and good viscosity-temperature characteristics
Viscosity is the first factor to consider when choosing a hydraulic oil. If the viscosity is too high under the same working pressure, the resistance to movement in the hydraulic components will increase, resulting in an increase in temperature, reduced suction capacity for the hydraulic pump, and an increase in power loss due to pressure drop in the pipeline. If the viscosity is too low, it will increase volumetric losses in the hydraulic pump, increase internal leakage in the components, and cause the oil film in the sliding parts to become thinner, which reduces the supporting capacity.
Good lubricity (anti-wear properties)
Hydraulic systems have many moving parts that require lubrication to prevent surface wear during relative motion. Especially in systems with high pressure, the anti-wear properties of the hydraulic oil must be much higher.
Good oxidation resistance
Hydraulic oil used in lifter jacks will undergo oxidation during use. The acidic substances produced by the oxidation will increase the corrosiveness of metals, and the sediment produced by the oil will block the filter and small gaps, causing the hydraulic system to malfunction. Therefore, good oxidation resistance is required.
Good anti-shear stability
As hydraulic oil passes through pumps, throttle valves, and gaps, it undergoes severe shear, causing some large-molecule polymers in the oil, such as thickening agents, to break into smaller molecules, reducing viscosity. When the viscosity drops to a certain level, the oil cannot be used, so good anti-shear stability is required.
Good rust and corrosion resistance
Hydraulic oil will inevitably come into contact with moisture, air, and acidic substances produced by oxidation during use, which will cause metals to rust and corrode, affecting the normal operation of the hydraulic system.
Good anti-emulsification and hydrolytic stability
Hydraulic oil mixed with water from different sources during work is subject to hydraulic pumps and other components.
Strong anti-foaming and air-release properties
In the hydraulic oil tank, air bubbles mixed into the oil during circulation will not only reduce the pressure of the system, worsen lubrication conditions, produce abnormal noise and vibration, but also increase the contact area between the oil and air, accelerating oxidation of the oil. Therefore, hydraulic oil needs to have good anti-foaming and air-release properties.
Compatibility with sealing materials
The poor compatibility between hydraulic oil and sealing materials used in lifting jacks can cause the sealing materials to expand, soften, or harden, resulting in a loss of sealing performance. Therefore, the hydraulic oil and sealing materials must be compatible with each other.