PDA

View Full Version : Nh3 systems







CT2
12-03-2006, 07:47 PM
I am looking for information on Nh3 systems . I work at a soft drink company and would like to understand the refrigeration system on our fillers. We have 10 Vilter compressors that range from 25 hp to 125 hp that feed three chillers in the filler room. next to each chiller appears to be a liquid reciever just before the metering device

thats about the extent of my knowlege and I cant find anything in my refrigeration books from school

thanks

Andy
12-03-2006, 08:13 PM
Hi CT2:)

Would these be "MO JO Plants:confused:

Mojourney plants, built in the good old USA for syrup cooling.

If they are I will explain their operation.

Kind Regards. Andy:)

CT2
12-03-2006, 08:37 PM
Andy , thanks for the reply

yes , the system cools the mix , it is then pumped into the filler where the mix and co2 are filled into the container

Andy
12-03-2006, 08:51 PM
Hi CT2:)

A simple flooded NH3 system.

liquid is feed from the receiver out side. This HP liquid is injected into the Surge vessel inside thru an injector nozzel, this causes circulation of the ammonia in the Surup cooling jacket the liquid entering goes to the top of the jacket, sucking cold Ammonia from the bottom of the Jacket and mixing it to the incomming ammonia by venturi effect. The charge is resonably critical in these systems, as is the condensing temperture and the opening degrees of the injector valve, all effect the proper circulation in the jacket.

Hope this helps:D

Kind Regards. Andy:)

CT2
12-03-2006, 10:38 PM
so if I understand you correctly the ammonia doesnt actually vaporize ,it remains in a liquid or saturated vapor in the chiller
does the ammonia vaporize in the system or do the compressors pump liquid?/ saturated vapor?

CT2
12-03-2006, 10:45 PM
how do you determine if the charge is correct. I understand that occasionally ammonia has to be added to the system. On each of the Surge vessels there is a sight glass and I have watched the level changing during operation

CT2
12-03-2006, 10:46 PM
please excuse my little knowlege on these systems , I would like to learn as much as I can about them

guapo
16-03-2006, 01:00 PM
Hi CT2,
I used to work in coca-cola, and now I am a contractor of their refrigeration. Most of the system is carbo cooler MO JO. What company are you working? eric

US Iceman
16-03-2006, 01:24 PM
Hi CT2,


so if I understand you correctly the ammonia doesn't actually vaporize ,it remains in a liquid or saturated vapor in the chiller

does the ammonia vaporize in the system or do the compressors pump liquid?/ saturated vapor?

The liquid does evaporate into a vapor inside of the coolers. The compressors only compress vapor, NEVER liquid.

I do not have any literature for the systems you have, but you may be able to find some information by doing a an internet search.

If I can find some information for you, I will post it here.

Please ask any questions you may have. We are glad to help.

Andy
16-03-2006, 08:41 PM
so if I understand you correctly the ammonia doesnt actually vaporize ,it remains in a liquid or saturated vapor in the chiller
does the ammonia vaporize in the system or do the compressors pump liquid?/ saturated vapor?
CT2 please see Icemans Post.

Kind Regards. Andy:)

Andy
16-03-2006, 08:44 PM
how do you determine if the charge is correct. I understand that occasionally ammonia has to be added to the system. On each of the Surge vessels there is a sight glass and I have watched the level changing during operation

Experience, is essential:D

Suction superheat is also required;)

Level is important;)

Also the product leaving temperature, the operator will have a good idea if the plant is cooling to it,s usualy standard.:D

Kind Regards Andy:)

CT2
23-03-2006, 04:23 AM
Andy , Guappo and us iceman

thank you all for your help

Guappo , I am working at the 7-up bottleing co of San Franscico

Us Iceman: I have tried several google searches on nh3 refrigeration and havent found anything that teaches plant systems . I work on night shift and unfortunatly the journeymen working day shift know the most about our system and are willing to share the least with the rest of us

we had a case the other night in which our product temps rose to 60 degrees F and thankfully with my limited knowlege of our system I was able to find the trouble and make the correction

US Iceman
23-03-2006, 01:43 PM
CT2, try searching on the RETA website.

http://www.reta.com

They will not have instructional material listed you can read, but you can order the industrial refrigeration books. Most of the information you need is within the first two volumes.

Yes it will cost you some money, but you WILL get some very good information on the basic systems.


...the journeymen working day shift know the most about our system and are willing to share the least with the rest of us

Job protection or just selfish. Unfortunately, this is encountered by most people starting out. Industrial refrigeration is the worse because the people that know something sometimes don't like to share.

I found this to be true when I started. I also used the RETA books at that time because they were the ONLY source of information available. Other than contractors or manufacturers who will help, but usually only when you are spending money!

CT2
23-03-2006, 05:10 PM
US iceman : thank you I will look at the sites you have mentioned . I dont mind spending money on books that will make money for me in the long run

Ken Cooper
28-03-2006, 09:12 PM
You can go to reta. com and get a order form and order refrigeration books. Its cheaper if you become a member. You can order the books and the exam and answer sheet and mail the answer sheet in to reta and they will give you a certificate. My company paid for my as part of training. I have recently completed Ref. course 1-2-3-4. Bacic electricty 1-2 and Control theory 1-2. hope this helps and good luck.

US Iceman
28-03-2006, 09:29 PM
Ken,

Have you taken the CARO or CIRO certification exams?

What did you think of the training material and books?

Thanks,
US Iceman

Ken Cooper
28-03-2006, 09:51 PM
Hellow US Iceman. No I have not taken the CARO or CIRO exams yet my employer told me if I wanted to take them they would pay for it so I will probably check in to in later. I found the books to be very useful Ref. 1-2-3-4- and basic Electyicty 1 and 2 However I found Control Theory 1-2 to be boring and a little to advanced for me at this time. I highly recommend Ref. books 1-2-3 and 4 for anyone starting out in NH3. Ref.

US Iceman
28-03-2006, 09:57 PM
Book 3 is currently undergoing revision at this time.

I also seem to remember hearing something about another book being revised, but I don't remember which one it is.

If your employer will pay for the certification exams you are a lucky one. Some employers are beginning to take this seriously, others are waiting for it to be free I think.:rolleyes:

sagittarius
29-03-2006, 06:54 AM
Hi,CT2.I am a new too.but I have read a book,maybe help you.The name is "Industrial Refrigeration HandBook".Mc Graw Hill published.

CT2
03-05-2006, 07:07 PM
Guapo , Iceman and Andy

well I got a bit of an education on our system and I walked away with a better understanding of how things work and what does what.

we have three frame and plate chillers and one of them leaked product.
only one of the mechanics there had any idea how this was assembled and that was years ago. he only remembered the factory rep putting it together.

we took it apart and changed the gaskets on all of the plates and put it together 4 times , still chasing the leak when someone remembered that we had three plates in stock from the installation.
after replacing the end plate and two additional plates we stopped the leak.
I evacuated the system on my shift, I should say the isolated part of the system, found a small ammonia leak with a smoke stick , fixed that leak , evacuated again and after holding 30 " of vacuum we put it back in operation
I do thank you all for your help, anthony

US Iceman
03-05-2006, 07:19 PM
When you say a "smoke stick" I am assuming you are using sulphur sticks??

Don't they smell nice.:eek:

CT2
04-05-2006, 09:41 AM
yes, sulphur sticks

yea , when you hit a leak I dont know what is worse , the ammonia or the smoke from the sticks

Josip
04-05-2006, 12:51 PM
yes, sulphur sticks

yea , when you hit a leak I dont know what is worse , the ammonia or the smoke from the sticks

:) :) Hello, CT2,

but definitely it is 100% proved that you have a leak:rolleyes: then you have a break (for beer) waiting for fresh air

Best regards,

Josip:)

US Iceman
04-05-2006, 01:10 PM
...when you hit a leak I don't know what is worse , the ammonia or the smoke from the sticks

My vote is for the sulphur sticks. Ammonia smells pretty good compared to the sulphur cloud.:D

AMARNATH JHA
04-05-2006, 01:21 PM
All the compressors compress low temperature low pressure vapour not liquid.If the liquid enters into the compressor chamber it is called liquid stroke which is very fatal for the machine.
AMARNATH JHA

Josip
04-05-2006, 01:41 PM
All the compressors compress low temperature low pressure vapour not liquid.If the liquid enters into the compressor chamber it is called liquid stroke which is very fatal for the machine.
AMARNATH JHA

:) Hello, AMARNATH JHA

yes, definitely must be vapour, but not necessarily low temp and low press :)

to pump liquids we use pumps not compressors,

it is dangerous causing damages but not fatal for all compressors:rolleyes:

Best regards,

Josip:)

CT2
15-05-2006, 07:06 PM
I am mostly familiar with refrigeration compressors and I

I wasnt there to see them draw the liquid out of the chillers reciever , but I was there when we slowly throttled liquid back in the tank, and that gave me a better understanding of what was taking place in the system