Hydraulic Fluids are considered as the most important requirement for any hydraulic system. In the fluid power industry, the primary factor that distinguishes hydraulics and pneumatics (the two important power transmission techniques) is the presence of fluids. Also, no operation is possible in a hydraulic system without any hydraulic fluid.
Hydraulic system uses incompressible hydraulic fluids(also called hydraulic oils/liquids) to transfer energy from one part of the system to another. These fluids are stored in a reservoir and during the operation of the hydraulic system the pump will suck these fluids and pass it through the pipings towards other components.
Hydraulic oils play an important role in improving the productivity of the system. Most of the hydraulic systems are designed for operations involving maximum speed, pressure, and temperature. Analyzing the oil for contaminants and providing proper maintenance to the oil will reduce premature failure of the system.
Hydraulic fluid is selected depending on the application it needs to perform. There are some properties for an ideal hydraulic fluid. It includes viscosity, lubrication properties, demulsibility(the ability to release water), chemical and environmental stability, fire resistance, low flammability ( Is hydraulic fluid flammable? ), foam resistance, low volatility, etc. We can discuss more related to these hydraulic fluids properties in another article. Here, the functions of hydraulic fluids are highlighted.
- Power generation:
Every hydraulic system work using Pascal’s principle. The incompressible fluid present in the system will transfer energy from one point to another and it generates the power for completing the operation. The pump in the system will initiate the flow and pressure is developed at the point of restrictions. Also, force multiplication and direction control are possible.
- Remove Contaminants:
The presence of contaminants will damage the system or reduces productivity. The contaminants can be solid particles or water content. Hydraulic fluids have an important role in removing these contaminants present in the system. The fluid carries all the foreign particles towards the filter.
- Lubrication and Protection:
Proper lubrication is required for eliminating the risk of wear and premature failures. Continuous sliding of the hydraulic component(pumps, motors, valves, etc..) parts will create high friction. The hydraulic fluids can reduce friction by creating a lubricating film between the moving parts.
- Sealing: Most of the hydraulic systems will use separate seals to prevent leakage and entry of foreign particles. But, the hydraulic components like control valves will operate with tight clearances. The hydraulic fluids present in between the mechanical parts will also provide sealing functions.
- Heat Transfer:
Continuous rubbing of components against the metal surface will generate excessive heat. The circulating fluid will remove the heat generated.