Chromatography Forum

Hi all,
i have just finished refurbishing an E2M30 Edwards pump ( i changed the blade kit and the clean and overhaul kit). I let it purge for some minutes and when i measured the vacuun it was 3,2x10-3 mbar which is extremely good. After a couple of hours it was 1.5x10-1, i opened the gas ballast valve for 15 minutes and it dropped to 3,4x10-3 mbars. 3hours later the external temperature of the pump was extremely high and the oil colour turned grey. I checked the blades, measured the distance to the rotors but it was good (0,07mm). I used a new bottle of oil from a different firm (ultra grade 19 but not Edwards) since i thought that maybe there was an issue with this lot of Edwards oil i had in my stock, but i still have the same problem. I would appreciate your help in this.

Thanks
Derick

I have not used the E2M30 but do use the E2M18 Edwards pumps. The oil in ours seems to discolor quickly right after changing it. We use Inland 45 oil which is clear when new, and not even a day later it will have a reddish/amber color which I think comes from the heat. I am not sure of the specs on the Ultra 19 oil, but I know the Inland 45 has very low vapor pressure for better vacuum, you may want to try that and see what happens.

Hi all,
i have just finished refurbishing an E2M30 Edwards pump ( i changed the blade kit and the clean and overhaul kit). I let it purge for some minutes and when i measured the vacuun it was 3,2x10-3 mbar which is extremely good. After a couple of hours it was 1.5x10-1, i opened the gas ballast valve for 15 minutes and it dropped to 3,4x10-3 mbars. 3hours later the external temperature of the pump was extremely high and the oil colour turned grey. I checked the blades, measured the distance to the rotors but it was good (0,07mm). I used a new bottle of oil from a different firm (ultra grade 19 but not Edwards) since i thought that maybe there was an issue with this lot of Edwards oil i had in my stock, but i still have the same problem. I would appreciate your help in this.

Thanks
Derick

When a cool pump starts up it often shows a good vacuum, later as the oil warms up the vacuum reading rises due to the vapor pressure of the hot oil. That is normal but going up to the 10-1 area is more than usual. The oil lube circuit should be rechecked. The oil blade in the EM pumps can be put in 90 degrees off as it is a square section. The rounded tips must be set into the counterbore so the blades rotates correctly. Also the distributor valve on the top of the pump stator must be assembled correctly. It is easy to tighten it down but have the rubber seal (disc) not centered. That will also affect the lubrication and then the vacuum. Both shaft seals should be open to the oil blade to allow oil pressure to build up.
"45" oil is synthetic fluid used in mass specs for stable peaks. Hydrocarbon oil peaks can vary slightly. Inland U19 is the same as Edwards Unltragrade 19, it is a higher temperature hydrocarbon oil originally designed for use in hotter running Edwards RV pumps. Now Edwards use it for all direct drive pumps as it is better than the original Inland 19. I suggest you invest in a small IR tempersture "gun", about $50 at Sears Hardware. This will let you check the actual oil box temperature for a monthly record. Mark a dot or cross below the oil level and measure at the same place each time. If you are using the Edwards oil mist filters we can supply the EMF Mist & Odor elements at the best prices, offering the Odor as a single item rather than only a 5-pack that Edwards sells. We also have MF30 filter elements at good prices. Check http://www.VacuumAndLowPressure.com for prices, free shipping on the EMF element sets.

I have not used the E2M30 but do use the E2M18 Edwards pumps. The oil in ours seems to discolor quickly right after changing it. We use Inland 45 oil which is clear when new, and not even a day later it will have a reddish/amber color which I think comes from the heat. I am not sure of the specs on the Ultra 19 oil, but I know the Inland 45 has very low vapor pressure for better vacuum, you may want to try that and see what happens.

I would think that the 45 oil would discolor due to contaminants from your process than due to heat. Although the pumps run hot, especially when used on LC-MS with the gas ballast open it is not enough to burn the oil that quickly. Off course there may be contaminants inside the oil box form process too. You probably won't see much difference on a vacuum gauge between the readings of these oils. 45 is synthetic fluid to give stable MS peaks. If you use EMF20 oil mist filters we can supply Mist & Odor elements at the best prices, free shipping from our website www.VacuumAndLowPressure.com. We also have small items for the auto drain kits if needed.

I would think that the 45 oil would discolor due to contaminants from your process than due to heat. Although the pumps run hot, especially when used on LC-MS with the gas ballast open it is not enough to burn the oil that quickly. Off course there may be contaminants inside the oil box form process too. You probably won't see much difference on a vacuum gauge between the readings of these oils. 45 is synthetic fluid to give stable MS peaks. If you use EMF20 oil mist filters we can supply Mist & Odor elements at the best prices, free shipping from our website http://www.VacuumAndLowPressure.com. We also have small items for the auto drain kits if needed.

Thanks for the info. That pump is actually used on an ICP/MS so there is all kinds of junk that gets pumped through the oil.