Hydraulic fluids carries many properties such as the range of the operating temperature and the viscosity, and these are all subjected to a certain standard set by the International Organization for Standardization or more commonly known as ISO. There are other standard giving bodies but ISO is recognized globally and followed by most. With these standards as guide, the manufacturer will be able to put every fluid under certain categories while buyers can easily choose the right fluid depending on their needs and applications.
Types of hydraulic fluids
The International Organization for Standardization has categorized fluid types based on their supply and availability as well as its applications.
- Mineral-Oil based Hydraulic fluids. They are so called mineral-oil based hydraulic fluids because it contains mineral oil as one of its base components. This is considered as one of the fluids that can be obtained at a lower cost but proven to give a high performance. The mineral oils in the components are classified into three which includes HL, HM and HH fluids. The HH type of fluids is considered as a refined type of mineral oil and contains no additives. It has the ability to transfer power with less lubrication but it cannot resist an increase in the temperature. Its applications in industries are very limited. Some applications include the use in manual operated jacks and pumps and hydraulic system with low pressure. The HL fluids are the ones that have oxidants and rust inhibitors in its components which are proven to be helpful in making sure that the system can withstand chemical attacks as well as contamination in its water content. Main application is in piston pumps. The last type is the HM fluid which has anti-wear additives.
- Fire Resistant Fluids. Compared to the mineral oil based fluids, these types of fluids create less heat even when burned. This is typically used in operations where the equipment is more likely prone to any danger of fire like in the metal processing or military operations.
- Environmental Acceptable Hydraulic Fluids or EAHF. In applications where there is a likely event of the fluid being leaked into the environment, the EAHF is commonly used in order to make sure there will be no negative impacts on the environment and the surroundings