R-717

[megaton]

Anyone ever work with industrial ammonia systems? I like to experiment with CFC and HCFC refrigerants, but most of my working knowledge is with ammonia equipment. Am I all alone?

[refer dude 2479]

I worked a little ammonia in the early 80's. Did not get enough of it to get good, but I did enjoy it quite a bit. If you are a solid hand at ammonia you will have no problems with freons. btu/# is much less for freons and you don't have to worry about driving all of the people out of the neighborhood if a little refrigerant gets away from you.

[megaton]

Originally posted by refer dude 2479
I worked a little ammonia in the early 80's. Did not get enough of it to get good, but I did enjoy it quite a bit. If you are a solid hand at ammonia you will have no problems with freons. btu/# is much less for freons and you don't have to worry about driving all of the people out of the neighborhood if a little refrigerant gets away from you.

300 yards is our minimum evacuation radius in the event of a "refrigerant release". (this is what the government calls a leak) I experiment with the halocarbons at home because of the legal implications of possessing ammonia!

I found that learning the refrigeration cycle was a lot easier when you can walk around (and sometimes climb into) the compressor, condenser, evaps, etc.

[ucp]

Ammonia has been sounding very intresting recently to learn about. Are Ammonia based refrigeration systems very similer to freon based ones? Can you suggest a good web site for trying to learn the basics?

[stenfam]

check out Vilter.
That is the one I have seen to be the best at pronounced education, that I have dealt with.
been a while.. but I bet it is vilter.com.

they do have god schools I KNOW. They may have some net stuff also.

dan

[mosquito coast]

I have been interested in this application:
http://www.homepower.com/files/solarice.pdf?search=ammonia

I wonder what sorts of material specific corrosion problems there would be?

[gbfromsd]

ammonia reacts with copper, brass, aluminium. all metals in contact with ammonia need to be of steel.

[lowtemp]

Ammonia systems require no driers. Ammonia will absorb and hold large amounts of moisture and not alter its refrigeration effect.

[shaun66]

used to work for CIMCO - too much travel
gone too much

[megaton]

Originally posted by gbfromsd
ammonia reacts with copper, brass, aluminium. all metals in contact with ammonia need to be of steel.
Anhydrous ammonia in the presence of moisture will dissolve copper and brass relatively quickly. Also do NOT use galvanized steel pipe, ammonia will strip the zinc coating off really quick. I have seen a 3/4 x 6" brass nipple completely dissolved overnight. When we perform maintenance on our compressors we will pump them down as close to atmospheric as possible and then bleed off the rest of the pressure into a 5 gallon bucket of water. I have used various pipe materials as a weight to keep purge hoses submerged in the bucket and have seen some surprising reactions between pipe, ammonia, and water!

[ucp]

Outside of what has been mentioned here already, what other major differences between cfc/hcfc systems -vs- ammonia? Do ammonia systems have expansion valves as metering devices? Does low temp ammonia have a pump down and defrost cycle similer to freon based freezers.
Thanks for any input!

[absrbrtek]

Its a surge drum not an expansion tank. This is used with flooded evaps. Then youve got recirc systems and the rarely used TXV on dx aplications.
Originally posted by ucp
Outside of what has been mentioned here already, what other major differences between cfc/hcfc systems -vs- ammonia? Do ammonia systems have expansion valves as metering devices? Does low temp ammonia have a pump down and defrost cycle similer to freon based freezers.
Thanks for any input!

[megaton]

Originally posted by ucp
Outside of what has been mentioned here already, what other major differences between cfc/hcfc systems -vs- ammonia?
Do ammonia systems have expansion valves as metering devices?
TXVs are used to a small extent, we use hand expansion valves to control liquid temperature (subcooling) between recirculators. Most modern ammonia systems will use a flooded evaporator/liquid overfeed setup. Liquid is subcooled in the recirculator by maintaining pressure with the compressor(s), liquid is then pumped to the evaporators and a liquid/gas mixture is returned to the recirculator where the gas is then drawn off by the compressor and sent to the condensor. Pumping the refrigerant is what usually confuses HVAC guys, but we do have +20 evaps that are fed with high pressure liquid and use TXV expansion systems.


Does low temp ammonia have a pump down and defrost cycle similer to freon based freezers.
Thanks for any input!

Every ammonia system I have operated uses hot gas defrost.
I will have to post pictures of some evaporator valve groups

[westcoast refer man]

Filter driers can be used in ammonia systems although not for water removal. Water combines with ammonia to form ammonium hydroxide, which in most situations is not harmful. Filter driers are better than strainers at removing mill scale, weld slag, and other solid contaminents that are common in ammonia steel pipe systems. Small amounts of water are okay, but moderate amounts skew the pressure temperature relationship of ammonia and can lead to higher than normal head pressures. Also, water can cause sludging of the compressor's oil, as well as cause corrosion in the system if sufficient amounts are present. In other words, yes, ammonia is more tolerant of water than normal refrigerants, but it can still pose problems to ammonai systems. Aluminum is acceptable material and will not react with Ammonia. There are manufacturers of refigeration components that use aluminum in there ammonia products. Oil is not readily miscable in these systems, which means on occaision the trapped oil must be removed (typically by manually draining it)from various vessels. Expansion valves are used, however liquid overfeed, high and low side floats are also common. Many types of compressors are used, but most typically reciprocating types are limited to relatively small systems. Since ammonia is such an efficient refrigerant, it is typically used for very large (100's of tons) systems and srew compressors are usually applied there. A good source of information can be obtained about Ammonia systems by reading "Industrial Refrigeration" by Stoecker, Business News Publishing Co. I'm sure it could ordered through any book store or internet service.

[refer dude 2479]

Originally posted by ucp
Outside of what has been mentioned here already, what other major differences between cfc/hcfc systems -vs- ammonia? Do ammonia systems have expansion valves as metering devices? Does low temp ammonia have a pump down and defrost cycle similer to freon based freezers.
Thanks for any input!

Ammonia is refrigeration for big kids. It is just a refrigerant and as such you could build a system similar to any cfc/hcfc system. The differances arise due to the nature of ammonia and not because of any system technology. Most ammoinia systems are industrial in nature and are large tonnage. Flooded or overpumped systems are the rule, and most low temp systems are two stage. Oil is a problem with ammonia in that it is not micsable with the ammonia and must be forced either manually or with mechanical devices to move back to the compressor. Ammonia is dangerous and should not be undertaken by someone new without the guidance of an experiance ammonia mechanic. It will kill or main you in a heartbeat.

[frozensolid]

A pound of ammonia expands to eight or ten times the volume of r-22. It is very heat sensitive, it goes critical at 270 something degrees. Everything about it is dangerous. You would not walk into a lion’s cage, without a lion tamer. Don't mess with an ammonia system, without an ammonia tamer.

[refer dude 2479]

Originally posted by frozensolid
A pound of ammonia expands to eight or ten times the volume of r-22. It is very heat sensitive, it goes critical at 270 something degrees. Everything about it is dangerous. You would not walk into a lion’s cage, without a lion tamer. Don't mess with an ammonia system, without an ammonia tamer.

amen to that. and even the lion tamer gets attacked some times. just ask roy.

[megaton]

Ammonia is refrigeration for big kids.
I LOVE this stuff!
http://bellsouthpwp.net/e/l/ellis460/EQUIP55.jpg
Receiver and recirculators
http://bellsouthpwp.net/e/l/ellis460/EQUIP (18).jpg
Frick RWBII 177 Rotary screw compressor (500hp)

These pictures are of typical ammonia equipment. The sheer size of this stuff is a different ballpark than HVAC, although the same principles apply. The pictured system cools a 600,000 sq. ft. warehouse with 11,000,000 cu. ft. of
-10 freezer space. Note that the bright orange receiver in the first picture is 18' tall X 54" diameter. The operating charge of this system is roughly 38,000 lbs. of refrigerant. This stuff can be dangerous because ammonia will explode at 15 to 26% concentration in air (much lower if it contains oil vapor, which is most likely). I have pictures of a plant that recently did just that.

ReferDude knows his stuff.







[Edited by megaton on 09-01-2004 at 10:59 PM]

[refer dude 2479]

Originally posted by megaton
Ammonia is refrigeration for big kids.
I LOVE this stuff!
http://bellsouthpwp.net/e/l/ellis460/EQUIP55.jpg
Receiver and recirculators
http://bellsouthpwp.net/e/l/ellis460/EQUIP (18).jpg
Frick RWBII 177 Rotary screw compressor (500hp)








It is just a refrigerant and as such you could build a system similar to any cfc/hcfc system. The differances arise due to the nature of ammonia and not because of any system technology. Most ammoinia systems are industrial in nature and are large tonnage. Flooded or overpumped systems are the rule, and most low temp systems are two stage. Oil is a problem with ammonia in that it is not micsable with the ammonia and must be forced either manually or with mechanical devices to move back to the compressor.
Ammonia is dangerous and should not be undertaken by someone new without the guidance of an experiance ammonia mechanic. It will kill or main you in a heartbeat. [/B][/QUOTE]

very nice.

and a p.s. to my earlier post.......

almost all of the installations ( at least the ones that I have seen) you can eat off of the equipment.

[megaton]

very nice.

and a p.s. to my earlier post.......

almost all of the installations ( at least the ones that I have seen) you can eat off of the equipment.

Thanks, The government is very high on cleanliness. If your equipment is dirty, they assume the same is true for your safety programs and compliance paperwork. Keeping a machine room clean is no small task, there are 9 compressors like the one pictured in this particular machine room. The smallest one has a 165 gallon oil charge. The largest one (pictured) has 320 gallon oil charge. Rotary screw equipment requires a lot of oil. We use high pressure liquid on a thermosyphon setup with a shell and tube heat exchanger just to cool the oil in these things. Our oil cooling capacity is roughly twice the capacity of a supermarket rack.
The evaporative condensors on this system evaporate about 70,000 to 80,000 gallons of water a day. The smaller of these condensors has 4 twin axial 60" fans, the larger one has 6. I like bein' a big kid, but the suction strainer cover on these compressors weighs more than a 3 ton hermetic compressor! Sometimes I'm a TIRED big kid!

[Edited by megaton on 09-01-2004 at 11:22 PM]

[ucp]

Originally posted by westcoast refer man
Filter driers can be used in ammonia systems although not for water removal. Water combines with ammonia to form ammonium hydroxide, which in most situations is not harmful. Filter driers are better than strainers at removing mill scale, weld slag, and other solid contaminents that are common in ammonia steel pipe systems. Small amounts of water are okay, but moderate amounts skew the pressure temperature relationship of ammonia and can lead to higher than normal head pressures. Also, water can cause sludging of the compressor's oil, as well as cause corrosion in the system if sufficient amounts are present. In other words, yes, ammonia is more tolerant of water than normal refrigerants, but it can still pose problems to ammonai systems. Aluminum is acceptable material and will not react with Ammonia. There are manufacturers of refigeration components that use aluminum in there ammonia products. Oil is not readily miscable in these systems, which means on occaision the trapped oil must be removed (typically by manually draining it)from various vessels. Expansion valves are used, however liquid overfeed, high and low side floats are also common. Many types of compressors are used, but most typically reciprocating types are limited to relatively small systems. Since ammonia is such an efficient refrigerant, it is typically used for very large (100's of tons) systems and srew compressors are usually applied there. A good source of information can be obtained about Ammonia systems by reading "Industrial Refrigeration" by Stoecker, Business News Publishing Co. I'm sure it could ordered through any book store or internet service. I'm curios. Do you think we might see Ammonia systems more often in smaller tonnages some day? Why is Ammonia preferred over cfc/hcfc systems in the industrial arena?

Thank you.

[westcoast refer man]

There are ammonia systems out there under 100 tons for sure. I don't know (doesn't mean they don't exist)of any manufacturers of small tonnage (5 tons and less)compressors. However, The biggest reason for the predominance of Ammonia in large tonnage systems is it's efficiency and installed cost compared to the usual players. On the down side, local fire departments usually have their own guidelines regarding adequate dispersion systems (systems that allow the local fire department to release the ammonia charge into water in an emergency situation)and there are no universally accepted codes for safety provisions that I'm aware of.

[megaton]

The main 3 reasons ammonia is used in larger systems is
(1) Efficiency. Lower horsepower required per ton of refrigeration
(2) Price! the going rate for ammonia is about 8 to 12 CENTS a pound. Calculate the cost for a 40,000 lb. charge of R-22.
(3) Pressure. Most ammonia systems operate with a high side pressure of 150 psig or less. Low side pressures range from 10" hg to 35 psig

Ammonia isn't used in most residential or commercial systems because of its PUNGENT odor. Great for leak detection (there's no question whether or not you have a leak in an ammonia system) but most people would become slightly unpopular with their neighbors after they choked half of the neighborhood out of their homes. If you've never smelled anhydrous ammonia, it can be very uncomfortable. The smell of ammonia gives way to the feeling of being hit in the nose rather quickly. Example: Cleaning ammonia is a 3 to 5% ammonia in water solution, Anhydrous Ammonia, Refrigeration grade is 99.885% pure and contains no water (theoretically). I have seen ammonia used indirectly in air conditioning systems. The school where I received my Operator I Certification used a Hasegawa 3 cylinder (still 65 hp) compressor for chilled water/ice bank air conditioning
http://www.nh3gccc.com
This is their website, check it out, they have 5 test systems and have a lot of pictures and information.
http://www.garpltc.com
This is the website for the school that I received Operator II and Technician training. They have some good information also.

[Edited by megaton on 09-02-2004 at 09:21 PM]

[frozensolid]

My understanding of moisture in an ammonia system is that it turns into aqua ammonia. Periodically this aqua ammonia needs to be drained out of the system. The aqua ammonia migrates to, and is drained from the evaporator.

Is this correct?

[refer dude 2479]

Originally posted by ucp

Originally posted by westcoast refer man
Filter driers can be used in ammonia systems although not for water removal. Water combines with ammonia to form ammonium hydroxide, which in most situations is not harmful. Filter driers are better than strainers at removing mill scale, weld slag, and other solid contaminents that are common in ammonia steel pipe systems. Small amounts of water are okay, but moderate amounts skew the pressure temperature relationship of ammonia and can lead to higher than normal head pressures. Also, water can cause sludging of the compressor's oil, as well as cause corrosion in the system if sufficient amounts are present. In other words, yes, ammonia is more tolerant of water than normal refrigerants, but it can still pose problems to ammonai systems. Aluminum is acceptable material and will not react with Ammonia. There are manufacturers of refigeration components that use aluminum in there ammonia products. Oil is not readily miscable in these systems, which means on occaision the trapped oil must be removed (typically by manually draining it)from various vessels. Expansion valves are used, however liquid overfeed, high and low side floats are also common. Many types of compressors are used, but most typically reciprocating types are limited to relatively small systems. Since ammonia is such an efficient refrigerant, it is typically used for very large (100's of tons) systems and srew compressors are usually applied there. A good source of information can be obtained about Ammonia systems by reading "Industrial Refrigeration" by Stoecker, Business News Publishing Co. I'm sure it could ordered through any book store or internet service. I'm curios. Do you think we might see Ammonia systems more often in smaller tonnages some day? Why is Ammonia preferred over cfc/hcfc systems in the industrial arena?

Thank you.

Here on the west coast ammonia is only used for industrial applications or special "heavy" commercial applications because of the health hazard to the public. When I first got into the trade, 1973, there was a small market that had an ammonia/brine system for the case and box refrigeration. This was an old system from the late 40's or early 50's. There was a small leak in the mechanical room, some of which drifted out to the parking lot. people complained about the smell and of the irritation to thier eyes and nose and any other moist area on the body. We got the leak fixed and the system charged, but within a week the fire department red taggged the store because of local health codes. The store never reopened. It was a great system, but the politics of protecting people had changed from the time that it had been installed.

By way of example to show the increased refrigerating effect if a pound of R-22 boils off at a saturation temp of 0 deg it will absorb about 95 btu at 39 psia. One pound of ammonia boiling off at 0 deg will absorb about 570 btu at 30 psia. You get a lot more refrigerating effect for moving a lot less refrigerant with ammonia. It keeps the size of the equipment down on large tonnage systems.

Had the chance to see this comparison first hand in the early 80's. The company I worked for ( whos name will remain unknown)did a large storage freezer job in the valley for a regional frozen food distribution plant. Every system in this facility was ammonia, and very nicely done and maintained. The unnamed company decided to go with a freon system (R-502) with open drive Carriers. This on warehouse had 8 5H120 compressors for the storage freezer and 4 5H60 compressors for the loading dock. The horsepower was about the same as the ammonia systems that were of comparable size, but the compressor displacement differance was stagering. The ammonia systems fit neatly into semi small mechanical rooms. The R-502 system was in a room that was about 50 ft by 20 ft and it was wall to wall.

Worked on another industrial packing plant in the valley that the same company built. It was R-22 overpumped system that held 22000 lbs of R-22. The customer actually put in a rail spur so that they could take delivery of the refrigerant by rail car. How stupid. It worked fine but what the heck were they thinking.

Oh well enough rambling

[megaton]

Originally posted by frozensolid
My understanding of moisture in an ammonia system is that it turns into aqua ammonia. Periodically this aqua ammonia needs to be drained out of the system. The aqua ammonia migrates to, and is drained from the evaporator.

Is this correct?

In my experience, aqueous ammonia will somewhat (combine?) with oil carry over, making a gooey gray sludge that will be trapped in the liquid line strainers (blocking refirigerant flow), or will seperate out in the "oil pots". (a small vessel located on the "drop leg" of the recirculators, or the lowest point in the system.) This may be true on DX evaps with electric or atmospheric defrost. All of the systems I have worked with use hot gas defrost, which will force almost anything out of an evap and back to the recirculators.

[Edited by megaton on 09-03-2004 at 04:59 AM]

[ucp]

I noticed the mention of recirculating liquid? Excuse my inquisitiveness, but are you guys saying the the liquid ammonia(liquid line) has to be recirculated? What is the reason to recirculate?

Thank you!

[smilies]

Originally posted by megaton

The smallest one has a 165 gallon oil charge. The largest one (pictured) has 320 gallon oil charge. Rotary screw equipment requires a lot of oil.

What kind of oil?



Originally posted by megaton

The evaporative condensors on this system evaporate about 70,000 to 80,000 gallons of water a day.

Pics of water line?



Originally posted by megaton

the suction strainer cover on these compressors weighs more than a 3 ton hermetic compressor!

Any pics of these as well?

[BHD]

Anhydrous ammonia

Makes a great fertlizer, farmers buy it by the ton,
the current price on fertlizer grade is about $375 a ton,

It will swrink dollar bills,
it will make a piece of red meat look cooked,
If you get in you eyes (liquid) you will more than likey lose you eye,
to storng of a wiff of it will take away you ablity to smell
it is a very hazardus product,

[megaton]

Originally posted by jerrycoolsaz

Originally posted by megaton

The smallest one has a 165 gallon oil charge. The largest one (pictured) has 320 gallon oil charge. Rotary screw equipment requires a lot of oil.

What kind of oil?
Frick #3, not sure of specifics of oil, never researched it because we have to use manufacturers oil for warranty.


Originally posted by megaton

The evaporative condensors on this system evaporate about 70,000 to 80,000 gallons of water a day.

Pics of water line?
Each condensor has a 3" galvanized steel supply line. Not much to look at. Trying to find pics of recirculator pump and make up valve.


Originally posted by megaton

the suction strainer cover on these compressors weighs more than a 3 ton hermetic compressor!

Any pics of these as well? 2" thick 14" dia steel plate.. Will post pics later

[refer dude 2479]

Originally posted by ucp
I noticed the mention of recirculating liquid? Excuse my inquisitiveness, but are you guys saying the the liquid ammonia(liquid line) has to be recirculated? What is the reason to recirculate?

Thank you!

Low pressure low temperature liquid is pumped from the pumping receiver to the coils. The coils are flooded with liquid refrigerant and the return line from the coil goes back to the pumping receiver. The high pressure liquid line enters the pumping receiver through a metering valve and flow is usually controled by a level float in the pumping receiver. The compressor suction draws off of the top of the pumping receiver. This is a simple explaination but I hope it helps.

[westcoast refer man]

Liquid is "recircualted" (aka liquid overfeed)in a ratio greater than the required flow rate (Liquid is feed at a rate greater than the evaporation rate). Example, if the needed flow rate to do the cooling is 1000 lbs/hr, and the recirc rate is 3:1, then the required flow rate is 3000 lbs/hr. The needed flow rate is just the refrigeration effect of a lb of ammonia liquid boiling off to vapor considering the tonnage involved. It's not hard to figure, but let's not get into that if we don't need to.

One reason plants and evaporators are set up in this fashion is to "wring out" all the possible btus that you can out of a given evap coil size. In other words, same coil with same surface, fins per inch, cfm, etc, you will get more tonnage out of it. the trade off is that you have to pay for a recirc. vessel, pumps, and the kw the make em run. There are other advantages and disadvantages as well. Recirc systems are primarily found in large tonnage plants where the various trade offs make financial sense.

[nh3man!]

NH3 is my home! I love this stuff. If there are any ?'s on this I would be happy to entertain! Maybe if there is enough interst we could get our own topic!!!!! :)

[kingvalve]

I worked in a large ammonia freezer/ice making plant in the late 1960's/early 1970's. I forget the tonnage of the system but it was definately several hundred, was a two stage system using Frick rotary comps for the 1st stage and 2 cylinder Frick recip comps for the 2nd stage. The largest of these 2 cylinder Fricks was a 12x12, that was a huge machine driven by a 500hp electric motor. In the summertime the heat in the plant was almost unbearable and the noise level even worse.
Does anyone else have experience working with these old 2 cylinder Frick comps? I have tried to find pics of them on the net without a lot of success. I assume they have been out of production for a long time. Thank you.

[nh3man!]

There are still many Frick, Vilter and York heavy duty compressors in use in my area. Mostly as backup but they still run and can take more liquid than there little brothers!!!!! :)

[Learner]

I did a little bit of NH3 work in the 70's, but not enough to be a pro at it.

Are sulphur sticks still used for leak testing? Where can they be purchased?

What are the various methods used for leak testing NH3?

[nh3man!]

The great thing about NH3 is it is self alarming!!!!!! Yes sulphur sticks are still use with great success!!!! Even the smallest of leaks are noticed!!!! Ya just gotta love this stuff!!!!!! Smells like MONEY!!!!!! :D:D:D:D

[Andy Schoen]

Originally posted by frozensolid
My understanding of moisture in an ammonia system is that it turns into aqua ammonia. Periodically this aqua ammonia needs to be drained out of the system. The aqua ammonia migrates to, and is drained from the evaporator.

Is this correct?

You are correct. The more scientific term is ammonium hydroxide. Ammonia is very hygroscopic, and it readily reacts with water to form this stuff.

westcoast refer man is quite correct in stating a refrigeration filter-drier in ineffective at removing moisure from an ammonia system. The problem is water becomes ammonium hydroxide too quickly for the filter-drier to do anything about it.

[Andy Schoen]

Not only is ammonium hydroxide called "aqua ammonia", I see where it is also called "Spirit of Hartshorn".

One might try calling Vilter's technical support and ask them what to do about the "Spirit of Hartshorn" in your ammonia system... :D

[nh3man!]

There is a desicant dryer for ammonia now but is very expensive. Also you can rent a unit and distill your own sysem. Takes several days on a large system but does work.

[Andy Schoen]

I'd be curious to know more about a desiccant filter-drier that can remove ammonium hydroxide. A google search wasn't helpful. In fact, it brought me back to this thread... :)

[kingvalve]

My most vivid memory of moisture (air) inflitration into an ammonia system is that it would slowly push up the head pressure of the system to the point where the air had to be bled from the system...or eventurally the safety valves on the condensers would lift.
Air removal was usually done on a Sunday morning when the plant was shut down for that purpose. I am sure there are now more sophisticated ways of doing the job but back then the preferred way of getting the job done was to attach a rubber hose to the top of the condenser and let 'er blow! Actually you were told by your boss to go slowly and allow only the air to escape but that was so dang slow, and besides, the boss was usually home in bed sound asleep on a Sunday morning so some of the shift engineers would string the hose outside and let 'er rip, by the time the hose had a nice coating of frost it could be safety assumed that there wasn't much air! left in the system. This was back in the early 1970's....oh, the memories!
If anyone else has stories of plant operations of times past, please post them...just don't incriminate yourself...too badly!

[megaton]

Originally posted by kingvalve
My most vivid memory of moisture (air) inflitration into an ammonia system is that it would slowly push up the head pressure of the system to the point where the air had to be bled from the system...or eventurally the safety valves on the condensers would lift.
Air removal was usually done on a Sunday morning when the plant was shut down for that purpose. I am sure there are now more sophisticated ways of doing the job but back then the preferred way of getting the job done was to attach a rubber hose to the top of the condenser and let 'er blow! Actually you were told by your boss to go slowly and allow only the air to escape but that was so dang slow, and besides, the boss was usually home in bed sound asleep on a Sunday morning so some of the shift engineers would string the hose outside and let 'er rip, by the time the hose had a nice coating of frost it could be safety assumed that there wasn't much air! left in the system. This was back in the early 1970's....oh, the memories!
If anyone else has stories of plant operations of times past, please post them...just don't incriminate yourself...too badly!

All of our systems use automatic refrigerated purgers, but from time to time we'll still have to "blast one off". The last one I had to deal with was a system that was shutting down on high discharge pressure...Operating with about 175 lbs of air in it! Took about 10 hours of gagging truck drivers to get that one solved! That's the downside of running a 14" vacuum on the low stage!

[megaton]

Originally posted by nh3man!
The great thing about NH3 is it is self alarming!!!!!! Yes sulphur sticks are still use with great success!!!! Even the smallest of leaks are noticed!!!! Ya just gotta love this stuff!!!!!! Smells like MONEY!!!!!! :D:D:D:D

Sulphur sticks make ya gag worse than the ammonia!

[kingvalve]

Well, the "ammonia room" has been quiet has a few weeks now. Everyone too busy getting ready for Christmas?

A question for you all - whats the oldest ammonia compressor you have seen - operating or otherwise? I know this may be a tough question as I am not sure the various manufacturers dated their compressors in a manner which was easy to decipher.

Personally, I have a fondness for old mechanical equipment, not sure if I would rather see a 1955 eight cylinder Chevy or a 1955 two cylinder 12x12 reciprocating Frick...or York...or Vilter. Have fun, hope to see you all back in the room shortly...

[megaton]

http://bellsouthpwp.net/e/l/ellis460/exp.JPG
The basic layout of a Frick rotary screw compressor package. Compressor is oil injected so it discharges through an oil seperator to remove oil from the discharge stream. The cover on the end is for access to the coalescer filters which remove most of the oil from the discharge gas. These compressors use oil for lube, cooling and rotor sealing, this unit has an oil charge of 225 gallons.
There are some pics of this systems recirculators and receiver farther back in this thread. This (and another) system cools a 600,000 sq ft frozen food warehouse.



Check out this website, there is a picture of a Frick 2 cyl built ca.1896 with a !!!27"!!!bore and !!!48"!!! stroke!
http://www.threshermen.org/clubprojectsFrame1Source1.htm

[Edited by megaton on 12-12-2004 at 02:01 AM]

[kingvalve]

Thanks, megaton, for the info, very informative, very interesting.

It would take me awhile to get the hang of operating an ammonia plant again after all the years of being away from it, the basics are still the same but the "accessories" have certainly changed.

How loud are those units, is hearing protection a necessity? The plant I worked in during the late 60's early 70's was a screamer, the two cylinder recrips weren't really loud at all, where the noise came from was 3 first stage rotary Fricks. They were loud to begin with, and liquid floodback was a frequent problem, once liquid started to slug back and the rotarys picked it up, they would scream like jet engines. Very hard on the comp vanes also, seems like every other year they had to be torn down for vane replacement. Very hard on the ears also, remember this was before hearing protectors had been invented...lol, actually no one wanted to wear them for fear of being called a wimp...lol.

[megaton]

These units are very loud. We were required to take dB readings to determine where hearing protection was required...Most machine rooms are 120-130dB (with multple units running). 30,000 hours runtime on a rebuild is a major selling point, as is "stepless" capacity control. I have operated some rotary vane units, the sound is a lot different than rotary screw units. rotary vane units have a high pitched whine, rotary screw units sound kinda like a 2 cycle Detroit diesel at full throttle. (if that helps any)

[Edited by megaton on 12-16-2004 at 07:53 PM]

[kingvalve]

Well, thought it was time to bring the R-717 out of the basement.
Who has had experience with industrial ice machines? Back in my ammonia days we had several North Star ice machines each capable, I think, of producing 50 ton/day. These machines used a rotating water rail assy which gravity fed a water supply down over the vertical cylinderical evap. A rotating ice cutter assy removed the ice from the evap on a continuous basis. I beleive each revolution of the ice cutter took possibly a minute or so.
The gear reduction for the water rail/cutters used a system whereby the gear oil was sealed in the reducer with mercury. Every so often for reasons which I do not completely remember, the mercury would leak out of the gear box and the oil would also be subsquently lost. The mercury and oil would then have to be replaced. This was back in the days before mercury became a hazadrous product...lol, it was handled without any precaution whatsoever, not ever a pair of gloves. In fact, if you forget to take off your gold wedding ring you would find afterward that the mercury had turned it from a gold to a silver/lead color.
Haven't seen a North Star ice machine in 30 years, I wonder if they are still being made?

[megaton]

Industrial Ice Machine = any evaporator with a bad defrost regulator! I haven't had much experience with ice machines, but the operator school I went to had all of their test systems set up on different types of ice machines. One system had an evap/scraper setup similar to the one you described...though I highly doubt any mercury was used in it!