How to match the air cooler of hydraulic reasonably

1. Expected value of oil temperature

   The working temperature of the hydraulic system is generally expected to be kept in the range of 30-55℃, the highest is no more than 65℃, and the lowest is no less than 15℃. If the hydraulic system cannot control the oil temperature within the above range by relying on natural cooling, an oil cooler must be installed. 

      Depending on the cooling medium, there are three types of coolers: air-cooled, water-cooled, and refrigerant. 

      The most commonly used in traditional hydraulic systems is a water-cooled oil cooler, which is generally installed in the return line or low pressure oil line of the hydraulic system. 

     In recent years, with the rapid development of the equipment manufacturing industry at home and abroad and the increase of people awareness of environmental protection, people not only have higher  requirements for equipment functionality and stability in use, but also raised questions about whether equipment energy consumption and emissions are environmentally friendly Claim. In terms of cooling systems, high-efficiency, energy-saving, carbon-reducing, and environmentally friendly air coolers are entering a stage of rapid development as their main components. Especially with more and more cases of air cooling for imported equipment, the advantages of using air coolers have been further proved and recognized.

   According to the functional requirements of hydraulic oil temperature control in the range of 30-55℃, air cooling is completely achievable. 

       At present, many people still think that the water-cooled type is better than the air-cooled type. This is completely a misunderstanding: whether the cooling effect can be achieved in general equipment use places has nothing to do with the cooling method. The key lies in whether the cooling power of the oil cooler you choose is the same. Match the heating power of your equipment (system). The simplest example: the heating power of the equipment is 1Kw, and you choose a cooler with a cooling efficiency of 0.5Kw, whether it is air-cooled, water-cooled or refrigerant type, it is impossible to meet your design requirements within the required time period. Going up is just doing it.  

       To be emphasized: In hydraulic systems, most failures are often caused by the cleanliness and temperature of the hydraulic oil not meeting the requirements.


      When you consider the expected value of oil temperature, also consider the two elements of ambient temperature and temperature difference (ΔT). Air cooling uses the air in the working environment as the cooling medium. During the heat exchange (cooling) process, the temperature of the air rises, taking away the heat from the radiator. Therefore, the temperature of hydraulic oil will be higher than that of hot air. Usually after the system reaches thermal equilibrium, the controllable range of the oil tank oil temperature is 10-15℃ higher than the ambient temperature. For example, the ambient temperature is 35℃, then the oil temperature can be controlled within the range of 45-50℃. More difficult. If the ambient temperature is 25°C, the oil temperature can be controlled below 35°C. The greater the temperature difference, the better the cooling effect. The premise of the above results must be achieved under the condition of matching the choice of cooling capacity.

Therefore, the expected oil temperature of hydraulic stations using air coolers is usually controlled within the range of working environment temperature + (10-15) ℃. If the temperature of your working environment is higher than 40℃, the most ideal oil temperature can only be above 55℃, and the use of air cooling is a bit reluctant. Only other cooling methods can be used.