Inpro Seal with trico Constant oiler...............

[ferreiro]

Hi all,
We have picked up a problem with a pump in the chemical industry.The pump has had a Inpro-vbx bearing isolator fitted.The pump has constant oiler and a normal breather.The client is complaning that the oil is draining off to quickly from the constant oiler into the pumps housing.The oil then is above the level of the seal and therefore drains away through the seal's drain motion.
The bearing isolator supplier has advised that the breather and constant oiler be removed with both holes been sealed and a site glass be fitted with a top-up pointbeen fitted.
Any persons..................
BestRobert

 

[JJPellin]

We have seen this problem regulary with the standard design Trico constant level lubricator. Usually the problem has to do with a pressure imbalance. Some pumps have a cooling fan on the coupling end that draws a sight vacuum along the shaft. This causes a slight negative pressure in the housing and the oil level in the housing rises accordingly. The oiler is tricked into adding excessive oil and the high oil level lets oil be drawn out along the shaft. This can happen even with a noraml breather vent. It is easy to test if this is the problem. Remove the breather temporarily. If the oiler stops adding oil and the leakage stops, this is the problem. I would recommend replacing the oiler with a pressure balance design. This configuration uses an equalization line from the oiler to the housing so that both see the same pressure. With this oiler you can plug the vent and reduce contaminants even further. Simply adding a larger vent could seem to solve the problem. But I have seen good data that the combination of a big vent with bearing isolators can increase the rate of air exchange to three times what it would be with lip seals. And any air exchange increases the introduction of contaminants (water and dust, mostly). Let me know if this is helpful and I can provide more detail if you like.

 

[assco]

A closed loop oiler from Trico and removal of the breather would work great. If oil contamination is a concern get rid of the labrynth seals and put magnetic isolators and a bullseye on the pump.

 

[electricpete]

One other aspect is placement of the oiler. For rolling bearing with lower ball ~ 1/4-1/2 in oil. The bearing acts like an oil pump. Oiler tap should be placed at the discharge side of that oil pumping action.

 

[MJDW]

Just a quick note, as we have been experiencing similar problems with these bearing isolators for some time. Originally we had VBX but when problem persisted that went to VBXX and we are now at VBXXD's ! Believe it or not there is another version about to be released.
The length of the isolator has increased from 13mm to +30mm in the mean time!
We have physically measured the bearing housings to ensure the settings of the oilers are correct and played with the housing vents to no avail.
Isolators are susceptible to higher oil levels, but we are not convinced that Inpro or their agents understand the mechanics of the oil in bearing housing, as they have suggested it is the pump manufacturers problem.
Watch this space.