How to Solve the Problem of Overheating in Hydraulic Systems ?

Overheating in hydraulic system is a common problem. Infact, after leaks, it is the second most serious problem that occurs in hydraulic machines. While the leak problem is easily accessible and solved, the problem of overheating is not well-understood by the user and hence leads to serious problem later on.

What is the main cause of overheating ?

Hydraulic fluid in operation heats up when there is inefficiency, which is caused by losses of input power. This gets converted to heat. The heat load in a hydraulic system’s is equal to the total power lost through inefficiencies. If the total input power lost to heat is more than the heat dissipated, the hydraulic system will overheat.

What should be the hydraulic fluid temperature?

The normal fluid temperature is 180°F. When the hydraulic system operates at temperatures above 180°F, it can damage most seal compounds and degrade the oil and hence this should be avoided. Usually, the fluid temperature becomes high when viscosity falls below the optimum value for the hydraulic system’s components. This is attained only when the temperature is below 180°F, depending on the fluid’s viscosity grade. To achieve stable fluid temperature, the capacity of a hydraulic system to dissipate heat must be greater than its heat load.

Solving the heat problem

There are two ways to solve the problem of overheating in hydraulic systems:

• Increase heat dissipation or
• Decrease heat load

It is to be noted that dissipation of heat of hydraulic system takes place through the reservoir. Therefore, it is necessary to check the reservoir fluid level. If the level is low, then fill to the correct level. There should be no blockage like buildup of dirt or debris to airflow around the reservoir.

Check the heat exchanger. Make sure that the core is not blocked. The ability of the heat exchanger to dissipate heat depends on the temperature and flow-rate of both the hydraulic fluid and the cooling air or water circulating through the exchanger. It is necessary to inspect the performance of all cooling circuit components. Replace them if required.

Drop in pressure means more heat

Heat is generated when there is a pressure drop. This implies that any component that has abnormal, internal leakage will lead to an increase in the heat load on the hydraulic system and can cause it to overheat. This can be the leaking of the cylinder or an incorrectly adjusted relief valve. Find out and replace any heat-generating components.

Conclusion

If you continue to use a overheated hydraulic system, your system will be damaged eventually. So whenever, you feel that your system is starting to overheat, shut it down, find the cause and fix it.