Hydraulic oil refers to a fluid which transmits power or carries a load in systems. It is used in stationary and mobile machines. In addition to power transmission, hydraulic oil lubricates mobile parts and cools the system. Hydraulic oil fulfills these requirements: suitable viscosity, pressure endurance and non-foaming properties.
Types of Hydraulic Oils
The two basic categories of hydraulic oils are mineral and synthetic. Mineral oils are refined from petroleum. Synthetic oils are manufactured polyalphaolefins or ester oils. Mineral oils are most commonly used because the supply of crude oil has made them inexpensive. Another advantage is that mineral oils can be produced in a wide range of viscosities for diverse applications.
Water is environmentally friendly, cheaper than oil and fireproof. Hydraulic fluid consists of 99% base stock, usually mineral oil, with 1% additives. Other base stocks may be required for specialty purposes.
Manufacturing Process
There are a few steps in manufacturing hydraulic oil. First, start with crude oil. Crude oil is refined to create a base oil. This base oil is mixed with additives to create the final hydraulic oil product.
Frictional resistance between hydraulic cylinders and seals increases with wedging. Hydraulic cylinders are made within very close tolerance standards. If tolerance standards are met, clearance remains within the wedging limit.