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gpeterman
30-10-2014, 10:16 AM
Hi all -

I need to pull down the NH3 main receiver to replace the manual gauge. I'm looking for a recommendation for a vacuum pump. The tank capacity is approximately 3000 gallons.

Thanks.

Glenn

RANGER1
30-10-2014, 11:28 AM
Gpeterman,
If you are just trying to get rid of a few fumes the cheapest suggestion is a steam ejector.
otherwise known as a Venturi.
use water & it dilutes the ammonia as you go.
good water pressure needed & a light non return valve in ammonia line connected to vessel.
it can pull 20" vacuum.
Water containing ammonia residue may not suit you though.
Another option we have used is a more expensive vacuum pump.

Tony
30-10-2014, 11:28 AM
The bigger the better - just make sure there are no brass or copper component parts in it otherwise the ammonia will eat them.

RANGER1
30-10-2014, 12:03 PM
http://www.busch.nl/en/products/product-portfolio/r-5/info/

Probably 10 m3 hr ok otherwise to big.
Suits 1/2" threaded connection.

http://www.gahanrahan.com.au/brown.pdf

steam ejector

Magoo
31-10-2014, 12:57 AM
Yellow Jacket in the US of A do an ammonia vac pump.

McFranklin
05-11-2014, 02:10 AM
If this is a one time thing you might consider having your ammonia supplier give you a quote to provide a pump out service.
Otherwise I have used Howe Corporations G series recips. They also make an aircooled system.
Additional many ammonia refrigeration contractors have an older compressor rigged up as a pump out machine.

Josip
05-11-2014, 08:17 AM
Hi, gpeterman :)


Hi all -

I need to pull down the NH3 main receiver to replace the manual gauge. I'm looking for a recommendation for a vacuum pump. The tank capacity is approximately 3000 gallons.

Thanks.

Glenn

Not sure, but I assume manual gauge means mechanical analog gauge.

This is a good example of a very bad design or only of very bad installation work.

This is very strange for me. Installation of the gauge without isolating valve. What a costly job when need to calibrate or replace a broken instrument.

Do you have some other connection to install that gauge in parallel instead to empty complete vessel!?!

It is possible to use some of the installed compressors to evacuate system vessel or some part of the system, but that is not very simple with main receiver.

Anyhow, with system compressor it is not possible to do the job that good as with a vacuum pump.

Best regards, Josip :)

RANGER1
05-11-2014, 12:14 PM
I first interpreted it as a level gauge, now not sure.

Josip
05-11-2014, 04:05 PM
Hi, RANGER :)


I first interpreted it as a level gauge, now not sure.


Maybe you are right anyhow there must be isolating valve/s ....

Best regards, Josip :)

Grizzly
05-11-2014, 06:12 PM
Just as an observation Guys!
I have been Pumping Down, Isolating, Purging and Vacuuming systems for many Years.
Many times I just use a standard Robin 5cfm Vacuum Pump.
The plastic handles go brittle and crack eventually as the ammonia fumes attack the plasticiser in the plastic of the handle.

Theoretically the copper / brass in the motor could be affected however I have yet to experience this!
Keep an older pump handy and when it does eventually fail then the loss is felt even less.
My colleague has an old small open drive vacuum pump which works a treat, don't forget you are only trying to boil off the traces once you have purged down to atmospheric.
Pete have you considered push pulling the ammonia into large pre vacuumed receivers.

Prior to purging off the residual vapours?
Grizzly

gpeterman
06-11-2014, 09:58 PM
Thanks folks for all the suggestions. This is the mechanical gauge (level transmitter) situated in the end bell of the horizontal main receiver. There are isolation valves for the different heat exchangers and condenser lines feeding back into the receiver. The packing o-ring is leaking and once the liquid is evacuated I wanted to be able to pull a vacuum on the receiver just to make I got the leak sealed.

Josip
07-11-2014, 12:13 AM
Hi, gpeterman :)



Thanks folks for all the suggestions. This is the mechanical gauge (level transmitter) situated in the end bell of the horizontal main receiver. There are isolation valves for the different heat exchangers and condenser lines feeding back into the receiver. The packing o-ring is leaking and once the liquid is evacuated I wanted to be able to pull a vacuum on the receiver just to make I got the leak sealed.

Maybe ... I'm not sure but hope you can do it ....

I think it is possible to replace packing with o-ring or only o-ring with both valves closed ... but then you need only to drain ammonia from the bottom of your level transmitter I believe a very small amount ... when you close the valve then ammonia is coming behind cone ...

then you remove packing gland with o-ring ... when you unscrew packing gland take care that spindle remain in closed position ...

even if valve is leaking a little it is possible (with good preparation of material needed) to do that under protection mask ... I suggest you to be two people to do that job ... I was there believe me ...

of course I can be completely wrong if your valves are of some different construction and not like this on link below, but I doubt ...

http://www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/01/PDKD0A902_SVA.pdf
... page 6 ...


valves are usually constructed and designed for easy change of seal for spindle

Best regards, Josip :)

Grizzly
07-11-2014, 07:13 AM
Hi gpeterman.
Thanks for coming back to us all with a further explanation!
2 things, as I think Josip is implying.
it is unusual to have a level column or glass etc, which does not have isolation valves either side of it?
Never seen it before.
The other is why are you using considering using a vacuum to prove a pressure vessel?
You got me there!
Of course I may be misunderstanding what you mean.

Grizzly

RANGER1
07-11-2014, 09:02 AM
Hi, gpeterman :)




Maybe ... I'm not sure but hope you can do it ....

I think it is possible to replace packing with o-ring or only o-ring with both valves closed ... but then you need only to drain ammonia from the bottom of your level transmitter I believe a very small amount ... when you close the valve then ammonia is coming behind cone ...

then you remove packing gland with o-ring ... when you unscrew packing gland take care that spindle remain in closed position ...

even if valve is leaking a little it is possible (with good preparation of material needed) to do that under protection mask ... I suggest you to be two people to do that job ... I was there believe me ...

of course I can be completely wrong if your valves are of some different construction and not like this on link below, but I doubt ...

http://www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/01/PDKD0A902_SVA.pdf
... page 6 ...


valves are usually constructed and designed for easy change of seal for spindle

Best regards, Josip :)

josip we obviously do not know exact type or brand of valve yet.
But with Danfoss there are a variety of valve designs, some from the earlier days where the gland actually hold washers that hold the whole spindle assembly in.
These older valves Sabroe/Danfoss the spindle does not move in or out, but moves shoe assembly internally.
These can catch you out if on front seat.
Have had this on Sabroe recips & older SAbroe/Danfoss valves.
It would be extremely unusual not to be able to backseat a valve to repair gland, but if in doubt pump it out, even if it's a atmospheric pressure or slight vacuum.

RANGER1
07-11-2014, 09:04 AM
Thanks folks for all the suggestions. This is the mechanical gauge (level transmitter) situated in the end bell of the horizontal main receiver. There are isolation valves for the different heat exchangers and condenser lines feeding back into the receiver. The packing o-ring is leaking and once the liquid is evacuated I wanted to be able to pull a vacuum on the receiver just to make I got the leak sealed.

gpeterman can you send a picture of valve in question if possible.

piewie
23-11-2014, 04:05 AM
Just use a standard vacuum pump and then change the oil once or twice when you are done. Nearly all the vac pump manufacturers do an ammonia compatible style pump.

Grizzly
23-11-2014, 11:40 AM
Just use a standard vacuum pump and then change the oil once or twice when you are done. Nearly all the vac pump manufacturers do an ammonia compatible style pump.

You did not bother to read my first post then?
Grizzly

sterl
08-12-2014, 05:20 PM
Fuller or Allis Chalmers rotary vane driven by an engine. That from one of the contractors with old compressors lying around....

weagle
22-02-2015, 09:18 PM
Just as an observation Guys!
I have been Pumping Down, Isolating, Purging and Vacuuming systems for many Years.
Many times I just use a standard Robin 5cfm Vacuum Pump.
The plastic handles go brittle and crack eventually as the ammonia fumes attack the plasticiser in the plastic of the handle.

Theoretically the copper / brass in the motor could be affected however I have yet to experience this!
Keep an older pump handy and when it does eventually fail then the loss is felt even less.
My colleague has an old small open drive vacuum pump which works a treat, don't forget you are only trying to boil off the traces once you have purged down to atmospheric.
Pete have you considered push pulling the ammonia into large pre vacuumed receivers.

Prior to purging off the residual vapours?
Grizzly

Best answer yet. Exactly what I was going to say