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b. The two lubricators were placed in the environmental chamber and subjected to different temperatures. Prior to starting each test at the given temperature, each lubricator was filled with 9 pails (143 Kg or 315 lbs) of the grease to be tested. At each test temperature, both lubricators were filled with the exact same grease. The grease was then leveled in the tank and a measurement taken for the height of the grease in the reservoir. At each temperature set point, the grease was allowed to acclimate for a minimum of 24 hours before testing commenced. The test greases were evaluated at the following temperatures:
a. 37.8°C (100°F) b. 50°C (50°F) c. 0°C (32°F) d. -17.8°C (0 F) e. -23.3°C (-10°F)
** Additionally, after the 24 hour acclimation period, the un-worked penetration of the test grease was also measured at each temperature for each grease. Grease was placed in a standard penetromer cup and the cup was placed inside the environmental chamber during the acclamation period.
c. Because a quantity of grease was lost from each prior test temperature, the grease lost (pumped out from prior test) was weighed and an equal amount of new grease was added to each lubricator to maintain consistency in testing procedures. The entire grease was then allowed to acclimate to the next desired test temperature.
d. The same grease was tested in both lubricators side by side and at the same time.
The testing included the following train simulations:
The digital train simulator was programmed to simulate twenty-five car trains with 60-ft truck centers running at 5 miles per hour (mph) or 8 kilometer per hour (kph). After each train, the system was shut down for one minute before the next train would starts. Based on past field experiences, it is estimated that about 0.8 pounds (36 grams) of grease should be pumped for every 100 axels passing the wheel sensor (two lubricating bars – one each side of the track). The goal was to program each lubricator in a way that 0.4 pounds (18 grams) of grease would be pumped for every 100 axels since only one lubricating bar was being used.
a. It was determined that the lubricator from OEM 1 unit set to pump for 0.35 seconds every 5 axles outputs 0.3778 lb (~18 grams) of NLGI grade 1 grease at 37.8°C (100°F) during one train pass using the simulator. The OEM 2 lubricator unit was set to pump for 3.5 seconds on every axle. The settings on the OEM 2 unit were such because a relay is used to simulate a wheel count every time the OEM 1 unit’s pump engages. It was also determined that the settings on the OEM 2 unit output 0.3908 lb (~18 grams) at the same conditions above. The output for each lubricator was similar in like conditions and was close to a desirable 0.8 pound (36 grams) per 100 wheels (figuring one bar system should be half of that).
b. Since each test started at the highest test temperature, after each test at each temperature, the environmental chamber was cooled to the next lower temperature and the grease and all the equipment were allowed to acclimate for a minimum of 24 hours
c. The same simulation was run at each temperature.
e. Grease output was weighed and new grease was added to the reservoir to make up lost grease in previous test.
1.2.1 Measurements The measurements recorded for each test grease during the environmental chamber tests is outlined below.
a. The weight of total grease pumped per temperature - lbs. b. Adherence of grease to steel (manual/visual) c. Funneling/cavitation. A measurement was taken at the highest and lowest point in the reservoir once each test run was completed. This was also considered a measure of slump-ability and show any funnel formation towards the pump inlet.
d. Unworked penetration of grease at each acclimated temperature (1/10’s millimeter)
e. A severe reduction in grease output is considered an indication of pump cavitation. In which case, output grease was examined for air pockets. Figures 1 through 4 show the arrangement of the two OEM lubricators in the environmental chamber, the quantity and position of grease in the reservoirs, and the position of grease dispensing bars in metal drums respectively.
Figure 1. The test grease dispensors from two OEMs (OEM 1 at left and OEM 2at right).
Figure 2. Arrangement of test grease dispensors and dispecing bars in the environmentalm chamber.
Figure 3. Placement of test grease in reservoirs to allow for observation of funnling and slumping.
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LUBE MAGAZINE NO.130 DECEMBER 2015
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