Hydraulic oil coolers are crucial to a hydraulic system for two reasons: they stabilize the viscosity of hydraulic fluid by keeping it at a stable temperature, and they remove excess heat that can degrade the performance and life of the circuit components. Specifying the correct cooler saves time, money and maintenance costs.
Essentially, a cooler removes excess heat from hydraulic oils by convective and conductive methods. The cooling medium, typically water or air, is circulated through a network of tubes extending from the cooler shell. The heat-absorbent tubes are designed with wide, high-cross-section areas to promote air flow and leverage the hydraulic oil’s natural ability to absorb heat. Coolers are also engineered to resist pressure losses.
Most of the cooler types operate on a conductive transfer principle where heat in the hydraulic oil is conducted into the cooling medium and sheds at a higher temperature. The fluid and the cooling medium move continually through the cooling system ensuring thermal saturation and equilibrium are never attained.
The main types of coolers include passive models that require no power and dynamic models powered by electric fans. Passive models feature wide cross-sectional surfaces and fins that direct the hydraulic oil into the air stream to transfer its heat to the coolant. The airstream then passes across the surface of the fluid and sheds its heat into the surrounding environment, reducing the oil temperature by up to 40°F.
Coolers are required whenever the hydraulic system’s heat generation exceeds the cooling capability of the reservoir, piping and hardware. Without a cooling system, the excessive heat will reduce the oil’s lubricating capabilities and cause premature wear on primary system components such as hydraulic pumps and motors.
Fortunately, hydraulic coolers are available in a wide range of sizes and mounting options to provide equipment owners with the most flexibility for their specific applications. They can be mounted directly on the tank or on the wall of a machine, or they can be remotely mounted up to 55’ horizontally and 110’ vertically to accommodate the needs of large mobile equipment, commercial and industrial processing machines, and other machinery with hydraulic power systems.
A cooling system is especially beneficial for equipment that operates in challenging conditions such as mining, construction, agriculture and trucking, where ambient temperatures are higher than usual. A properly sized hydraulic oil cooler can also eliminate hot oil problems such as nuisance shutdowns, bounce and chatter, and leveling issues caused by overheated hydraulic fluid.
Overheating is a leading cause of hydraulic system failure. The excessive heat robs the hydraulic oil of its natural properties and it becomes thick and loses its non-compressible qualities, turning into a system-degrading goop. Overheating also shortens the seal life of the hydraulic system’s components. The proper installation of a hydraulic oil cooler prevents this damage and allows for the continued safe operation of equipment under a wide variety of operating conditions. Bowman offers a full line of hydraulic oil coolers that are sized to match the heat load of the system. A computer based selection program can recommend the ideal model for a given application.