The Role of Hydraulic Oil Coolers
Hydraulic oil coolers remove excess heat from the oil used to lubricate equipment, vehicles and machinery. They prevent the system from overheating, which leads to a drop in performance and a significant reduction in equipment life. This article describes the role of the hydraulic oil cooler and how to select the right one for your application.
A hydraulic oil cooler is a heat exchanger that uses either air or water to cool the hydraulic fluid in the system. The system works by passing the hot oil through a radiator-like core that is exposed to a constant flow of colder water or air. The cooling medium absorbs the thermal energy and carries it away from the oil, where it is shed into the atmosphere.
Over time, this causes the thermal energy to build up in the oil, causing it to heat up. This has two negative effects: It reduces the effectiveness of the oil as a lubricant and causes the components in the system to suffer from excessive wear due to reduced viscosity.
The temperature of the oil affects its chemical stability in the presence of oxygen, which accelerates the oxidation process. This shortens the life of the oil and, if not dealt with, can cause significant damage to the system. Depending on the system design, this can lead to loss of production and costly repairs.
Arrhenius’ law states that for every 10°C increase in oil temperature, the rate of oxidation doubles. This explains why it is so important to keep the bulk oil temperature as low as possible.
A system is designed to work at a specific viscosity and, when the oil starts to thin, this will cause mechanical damage to the seals and moving parts. It will also reduce the efficiency of the hydraulic system as it is less able to deliver the required power.
As such, it is crucial to maintain the correct oil temperature and a properly installed and sized hydraulic oil cooler is vital for this. Bowman manufactures a wide range of marine oil coolers to suit most applications. These are available as a shell and tube, brazed plate or bar plate product and they can be supplied with or without fans and motors. They can be used with fresh, clean or contaminated sea water and can include sealing rings for easy maintenance of the cooling tubes.
Bowman’s range of oil coolers are available with Cupro-nickel or titanium tube stacks and all units are fabricated from stainless steel to allow them to operate in a variety of conditions. It is recommended that all Cupro-nickel tubes be ‘conditioned’ prior to use in order to create a natural protective layer of oxide on the inside of the tube, which protects them from corrosion and helps extend their lifetime. We regularly hear of marine oil coolers that have been in service for over 20 years! Contact the team at Bowman for advice on selecting the correct unit to suit your system. We can use our computer aided selection software to determine the most appropriate model for your application.