View Full Version : Small electric oil pump

16-09-2013, 08:50 PM
Can you recommend me a small electrical driven oil pump for NH3?
Purpose: long oil cooler lines to an aircooled oil cooler holding thick oil at a longer standstill at lower ambient temperatures.
This pump should help at startup to overcome the pressure drop in the cold coil till the oil reaches a certain temeprature and becomes less viscous.
There's now a problem it takes to long before we have a proper oil circulation in the coil and we go over the safety time of the oil flow.
Another idea: installing a PHE inside the machine room and using the now oil cooler as a glycol cooler, cooling the PHE. This is more work and more expensive.

16-09-2013, 09:03 PM
Can you not fit an oil heater or is this not practical?

16-09-2013, 09:21 PM
Hello Brian,...no, impossible. The lines are not the biggest problem but what to do with the horizontal oil cooler of +/- 4 m long and +/- 1.2 m width? We can't heat up the whole cooler coil at an ambient of -10C. Bitzer recommends heating the oil up till 20C.
The oil in the oil separator is electrical heated with 2 submerged heaters.
But as soon oil needs to be cooled, the 3 ways valve gradually turns open to allow flow to the oil cooler but the flow then decreases due to the thick oil in the lines and coil.
I haven't noticed this myself but the owner says this and the original installer admits 'there's a problem'
The Court appointed me to find a solution for this.
If we could help with the circulation through the outside coil at +/- 15 m from the machine room, then we can start up I guess. I know Sabroe and Stahl did this in the past.
The machine now needs to be started in winter after a cold weekend standstill +/- 5 times or more before proper oil flow is established.

16-09-2013, 10:25 PM
Hi Peter.
Have you concidered changing the type of oil.
To one with a lower pour point. Many of the newer Semi or ful synthetics operate at extremely low temps.
Is this an option you have concidered?

Transfer Pump details:-

http://www.rpm-fuels.co.uk/fuel-pumps/piusi-viscomat-gear-oil-pump.aspx (http://www.rpm-fuels.co.uk/fuel-pumps/piusi-viscomat-gear-oil-pump.aspx)

Open drop down menu for options.

This pump is listed as in 110v option only being available in 60hz 110v.

I have used American 115v (110v) 60 hz Power tools at home and
There is no problem!

This type of pump is self primimg and suitable for refrigerant oils.
The link is a UK one but I am sure this type / brand would be available to you within your home market Peter.



23-09-2013, 07:12 PM
Grizzly and others, have you ever used this type of HP pump?http://www.th-witt.de/witt/useranhaenge/liste/en/06_wor/02_bdp2/01_bdp2_manual_en.pdf

The link for the electric pump you gave me Grizzly seems also interesting. Is it suited for NH3? Pressure is anyhow not a problem I see

23-09-2013, 07:49 PM
Hi Peter.
I have used Witt semi and Hermetic pumps many times.
But have yet to come across the version you show above.
Sorry i cannot help further.
The transfer pump I gave you the link for. I only use as that, meaning to add new oil to systems.

I doubt it would be much good as a permanent option.


23-09-2013, 08:02 PM
Even with a pump you'll still be pumping (possibly) -10c oil to the compressor, surely you will still need to heat it?


23-09-2013, 08:13 PM
Hey Peter, I have a pump like that, it is practically new, The plant I have used for is closed.

if you want it, I can pack it and send it over, Just let me know.

23-09-2013, 10:08 PM
1078810788This is the schematic. The detail of the compressors in the middle can be fond in the pdf.

23-09-2013, 10:25 PM
Thanks Chemi but it isn't for me, I'm only allowed to make proposals to solve some problems with the setup.

mad fridgie
23-09-2013, 10:48 PM

24-09-2013, 04:00 PM
Hi Peter.
Sorry I forgot to mention the Pump I originally listed.Was because it is suitable to carry around in an mobile engineers vehicle, being 240v 0r 110v (115v american but works happily on 110v 50hz!).
There are quite a few available if you concider a 3ph motor.
Good Luck.

25-09-2013, 12:40 AM
What about a Danfoss oil burner pump, positive displacement, and usually has flare fittings but could be removed for steel nipples.