5.1 Sampling: Sufficient grease samples should be prepared for each test to fill 2 test ball bearings (each ball bearing needs about 4g);
A minimum of 15g grease samples shall be provided;
(3) Check whether the sample is not uniform, such as oil, phase change or pollution.
If any of the above occurs, a fresh sample should be taken.
5.2 Preparation of the instrument: Rinse the water storage tank and the water flow channel with distilled water, and wipe off the grease deposited on the surface of the tank.
Clean the test bearings with cleaning solvent (5.2).
Ensure that the water flow rate can be maintained at the specified speed during the experiment of 60min.
5.3 Fill the weighing ball bearing with 4.00g±0.05g grease sample, put the ball bearing and the weighing protective plate into the bearing sleeve, and install the component on the shaft sleeve of the water storage tank.
Record the quality of ball bearing, protective plate and grease to 0.01g.
5.4 Inject not less than 750ml distilled water into the tank, but keep the water level below the bearing sleeve, and do not start the ball bearing running.
At this time, a section of rubber tube or a piece of metal baffle is connected to the capillary nozzle to prevent water from spraying on the bearing sleeve, and the water circulation pump is started to control the water temperature to reach the required test temperature. If the test is conducted at a higher temperature (79 ° C ±2 ° C), a pre-selected heat source is needed to heat the water to reach the specified temperature.
5.5 When the water temperature reaches the specified temperature, adjust the by-pass valve to make the water flow rate be 5mL /s± 0.5mL /s, adjust the water nozzle position, and make the water beam just spray on the bearing protective plate 6mm above the opening joint of the bearing housing.
5.6 Start the motor and make the bearing run continuously for 60min±5min at a speed of 600r/min±30r/min.
5.7 After the end of the experiment, turn off the motor and heater, take off the test ball bearing and the protective plate, and place them on the surface dish that has been weighed. Separate the protective plate and the ball bearing, and turn their inner surface upward to expose the wet grease to the air.
5.8 Dry the ball bearing and protective plate in an oven at 77 ° C ±6 ° C for 15h, cool them to room temperature, then weigh them and determine the amount of water loss of grease.
Accurate to 0.01g.
Grease left on the guard plate and grease lost on the surface plate during drying shall not be counted as water loss.
Note: Grease containing low viscosity base oils may cause some quality loss due to the evaporation of lubricating oil during drying.
The drying humidity of grease containing high viscosity oil is increased to 93 ° c ±3 ° C in order to remove moisture during the specified period