Regulations on hydraulic oil and grease for dowty retarder

The provisions of the original standard for hydraulic oil and grease of the dowty retarder are too specific and meticulous, and do not meet the principle of maximum freedom set by the standard. There are also many inconveniences in the implementation of the standard. The new standard only stipulates the pour point and freezing point that affect the low-temperature use performance of hydraulic oil: "The pour point of the hydraulic oil used in the dowty retarder should be 15 C or more lower than the minimum temperature in the use area or the freezing point should be lower than the minimum temperature in the use area 18 C or more."

The pour point refers to the lowest temperature at which the cooled sample can flow under specified test conditions. Freezing point refers to the maximum temperature when the oil surface of the cooled sample no longer moves under the specified test conditions. Usually the pour point of the same oil is slightly higher than the freezing point, as long as the pour point or freezing point of the hydraulic oil meets the above requirements, it can meet the normal use of the dowty retarder.

The new standard also stipulates that "the grease of the dowty retarder should meet the requirements of the return time", that is, as long as the grease can meet the requirements of 5.1.8 for the return time under the conditions of the lowest temperature in the area of use. According to this principle, each design and production unit can specifically determine the performance index of the grease and select the grease.