Frick Premature Seal Failures

We have a new account that has a Frick RWBII 100E R-22 that has experienced several seal failures. We were able to view the last seal. The mating surfaces were in good shape however the O- rings were stretched.

I think the seal was installed the first of 2006 and the drip rate was 0 and is now 10 drips per min.

Other data: R-22, suction 9 psi (.6 bar), head 142 psi (9.79 bar), discharge temp 147* (63.9C), oil separator temp 142* (61.1C), oil cooler in 146* (63.3C), oil cooler out 101* (38.3C).

Oil analysis good with Clavus 68 oil. No apparent vibration (no previous vibration analysis). Alignment status good.

This system has two compressors in parallel it was relocated from another plant I believe it was previously NH3 now R-22. No problem with other compressor. The problem compressor operates loaded to about 50% or less most of the time.

Any ideas?

Thanks Steve

Hi Steve, with regards to your leaking shaft seal, have you checked the end float?
How many hours has the compressor done?
If the compressor has in excess of 30K hours and the float is out of tolerance it would indicate the need for major overhaul/bearing replacement.:o

Kind regards

Chopper

Hi Steve, I had the same thing some time ago (2001) with some seals from Howden on Ammonia screw Compressors units. Had to pump down and change 2 of the seals in 4 weeks, no fun with the motor weight of 3/4 of a tonne every time you had to check and adjust the realignment of the drive coupling. It turned out to be that the seals had come in with the wrong type of rubber "O" ring's. When you looked at the "O" rings they seemed to be over sized or stretched.
Has the Danfoss CD been OK.
Arthur

Arthur has a good point on the O-rings. Different elastomers will react to a change in fluids or refrigerants.

Sometimes they swell up, so after the O-ring is removed they looked stretched out or larger than the original size.

In other situations, the O-rings can become brittle and leak.

I don't know if Frick uses a different elastomer for ammonia or R-22 in their seals, but I do know that leaks can sometimes develop after the refrigerant has been changed to a different type. Same thing applies to oil also.

Frick has a very string statement about using their own brand of oil to maintain the compressor warranty. If the system was originally using NH3 and a semi-synthetic oil and was afterwards changed to R-22 and a mineral based oil, anything could possibly happen. The shaft seals are usually the first thing to show up.

Sorry for not replying earlier Steve. Your PM came in during the middle of a problem I was involved in.

Best Regards,
US Iceman

having dealt with fricks for many years I would bet on mis alignment or a motor that has some movement laterally on the shaft. i does not take much of an alignment problem to damage a seal face or oring seals

As to oil Frick they for years used Sun oil for their product.
nothing special, but the mention of the oil was more to keep from mixing several types and to get replacement sales.
.

Sorry to weigh in so late. Missed this one as it came by.
We have experienced this problem many times. Almost always after a plant has changed to a different type of oil.
My understanding is that in the last few years many Oil Suppliers have increased the solvent content of their oils. This affects the O rings causing them to fail.
The Rubber parts in a seal may change from time to time. An old stock seal may use a different formulation than current production.
Another problem that can occur is if you let the Seal parts contact solvents. (This happened to me) Automotive Brake Cleaners which many people use can cause some O rings to swell on contact.
I have also noticed a lot of Manway gaskets on Screws being very badly swollen lately on NH3.
According to information we have, Manway gaskets on ***** systems must be of VIRGIN Neoprene to avoid deterioration. I recently had a problem and cut my own out of 60 Durometer Neoprene.

As noted above, first the hours on the compressor and the end float.

Next, the history of the machines. Was all of the old oil removed? Were the seals renewed wit hthe refigerant and oil change.

If there was an oil change, is the new oil compatible with seal materials?

Taking the machines out of ammonia service and going into R22 may be part of the problem. There have been several articles about possible contamination due to the ammonia absorbtion into the cast iron casing. My approach on this has been to diassemble the compressors and chemically boil the parts to insure cleanliness and reduce the possibility of contamination. Also, the oil systems needs to be throughly flushed and charged with new oil of the proper type.

Good luck,
Ken

TXiceman;
Very good about the possible contamination in the castings. That had never occured to me. Do you have any of those articles in electronic form?

There is one reason why any oil company or compressor manufacture says dont mix oils. The types of additives in the oils are usually not compatible with other oils. This can lead to changes in oil chemistry, the anti foaming agent in one oil will react with the anti foaming agent in another oil and create a foamy mess. Also the change of oil type from a Mineral Based oil to a Semi or Full synthetic will cause problems. There are more solvents in the Mineral based oils and this results in seal swell, when changing to a Semi or full synthetic it results in the seal trying to shrink back to its original form, but it has already taken a set and will end up being loose. There is even a problem with some PAO and HT oils that they are too pure and result in the original elastomeric components of the seal being taken out. Some of these oils now have seal swell agents marketed as seal conditioners. All this does it attempt to replicate the level of oils found in the seals so they do not shrink.

Oh BTW I also share TXiceman's view from first hand experience, never change compressor from ammonia to another refrigerant or vise versa, without disassembly and cleaning, too many microscopic voids in the castings that can lead to contamination. I am even leary of System change outs from R-22 to Ammonia with out massive cleanup efforts.

NH3LVR,

There have been some articles published within IIAR I believe. There have also been a few Corporate "White Papers" published. I will have to see if I can locate one of these tomorrow in my archives.

I purged a lot of old stuff from my files last year. Some are in storage until we get our house completed and move in.

Ken

TXiceman
Appreciate the efforts. A slight delay while you take care of personal business is not of consequence.
Strangely enough one of our accounts plans to change from a Synthetic to Capella tommorow. We shall see how it goes.

NH3LVR,

Why is the customer changing oil types from a synthetic to Capella?

Have they been experiencing problems, or just concerned about cost?

hi
sorry to jumpin here for a question im new here and cant seem to find out how to post my own question.
where do you post from!

icetec9,

Go the Industrial forum and pick a sub-forum you feel is applicable to your question.

There is a button that says something like "start new thread".

Click on that and you are off and running.

Welcome icetech9!
USiceman-I do not know the reason. It was mentioned today as a possibility. I talked to the boss tonight and he told me if I go out there tomorrow that it will be going on. Am not too sure this is a good idea. Will keep you informed if anything strange develops. I am concerned as we will not be able to get all the oil out of the coalescing filters and chambers-much less out of the casting. My part is too upgrade the Software (Frick) and troubleshoot a Liquid Injection problem on another machine.

From experience and testing the coalescing elements may contain up to a couple gallons of oil in the fibers. We weighed them before and after to try to get an understanding how much the picked up and on a 30"x12" element they picked up anywhere from 7 to 12 lbs after being exposed to oil. Its better just to change the elements. Hopefully you can talk them in to doing the elements.

Are they going to just drain the separator, change the filters, clean the stainer and add?

Are they going to just drain the separator, change the filters, clean the stainer and add?[/quote]

Seems like that is the plan. Am not in the shop this morning. We are waiting for a delivery of a check valve from Denmark before going out. This machine is cobbled together with a second vertical separator having been added. A total of six filters I believe. A lot of room for trouble. Hopefully reason will prevail, or we will get lucky. I will point out the extra oil in the separator filters when we get there.

I can not understand the reason for changing the oil from a synthetic to a mineral based oil unless he is running mineral based oils in other machines and wants the common oil in all.

As for changing oils, be very careful and get all of the old oil out of the system. Change the oil separator elements and oil filters. Pressurize the oil system blow all of the low points to get the maximum of the oil out.

As noted above, oil manufacturers will generally state that they can mix oil, my experinece has been not to mix oil types or manufacturers. They use different additive packages and can cause problems when mixed. They can also use different viscosity improvers.

One of the most common problems seen when mixing oils is an increased in oil carry over and more oil foaming in the crankcase or oil separator.

If the oil is not throughly removed prior to a change, the unit will ofetn require a second oil change in a week or two to farther clan the oil system.

I can not find the paper on cross contamination on NH3/R22 conversions.

Ken

Quote:

---

Originally Posted by NH3LVR

Hopefully reason will prevail, or we will get lucky.

---

Myself, I would rather approach this as a planned attack. The changing to different oil types makes me nervous for all of the reasons already stated.

I would like to find out what the reason is for changing the oil in the first place. More problems may be created than those hoped to be solved, if you know what I mean.

Ken, are you thinking of the paper written by Ron Cole I believe?

Thanks guys - very interesting thread. We have used PAO for ammonia for the last 15 years or more. It is about 50% more expensive than typical mineral oil, but is pretty well indestructible, so oil life is not an issue. In the early days we had occasional trouble with leaky o-rings - typically about one job in ten would have a leak somewhere, but could be any o-ring from compressor body, shaft seal or solenoid valves. We now use CPI's version of PAO with their seal conditioning additive: you can buy the oil and additive ready mixed, or even small pails of additive to put in existing plants. No more leaks and no other problems = money well spent!

cheers
Andy P

I think Ron's paper was presented a few years back at IIAR. I don't have ready access to these papers, maybe you do. I also believe Mike Laukes did an internal paper at FES.

Ken

I must apologize. I was misinformed as to the nature of the Oil being used in the plant I referred to.
It is not a synthetic.
Changing from one mineral based oil to another is not of as much concern to me, although I realize there still could be problems.
I spoke to the Facility Manager yesterday. He was concerned about foaming with the oil he had been using. Also he has used Capella for many years and is comfortable with it.

I know some oils are more prone to foaming with a particular refrigerant than some others. An ammonia, Capella and Suniso both have a good track record for a mineral based oil.

However you still need to watch for a time after the oil change as the old oil may cause some excessive foaming for a period of time. Just be sure and blow down all of the low points to get as much oil out as possible. It is still a very good idea to replace the coalescer elements as they hold a fair amount of oil. I would also dump any recliamed oil for the next month if you have an automatic oil reclaim and return system.

I would also recommend they you get an oil samlpe for analysis after 40 hours of operation. I know this may seem extreme, but I have seen problems with a simple oil change as you are looking at now.

Ken

I agree with TXiceman, dump the reclaimed oil and do some sampling. The additives that manufactures use for pour point depressants, anti foaming agents, anti wear additives and other modifiers differ between oil brands. Sometimes when oils are mixed it causes reactions between the agents, I have seen where oil brands are mixed they can become a foamy mess in the compressor as the additives react with each other.

Sorry to come late on this one,
But it depends which Frick Compressor you are talking about. For the TDSH 163 and bigger, there are actually at least 2 type of seals available.
The standard type is steel to carbon type, and I have seen it leaking quiet often.
The revision type, is actually a York Shaft seal, the one that were on the YCCH compressors, and they are carbon to carbon type.
We have some special marine applications where all the shaft seals have been replaced to this carbo-carbon type and we haven't had any problems for the last 5 years.

There is a retrofit kit available to move from the standard type to the revision type.

Have had similar problems on several makes of screws, if set has been relocated check that it is firmly anchored down and have lazer alignment techician check coupling alignment cold then recheck hot alignment, set to a medium. While coupling is split get end float checked and motor bearing checked. Motor bearings should be minimum C3 grade/ close tolerance.But generally if o/ring appears to grow it is of wrong compound and will lose all sealling charactoristic.
Hope this helps
Magoo New Zealand:)

York/Frick has 2 types of seals. The bellows style and the spring type. The spring type has failures regularly with the dynamic oring failing and sticking to the shaft causing the spring tension between the faces to get out of spec.

The bellows seal is a great improvement over the spring style. The seal life is greatly improved.

absrbrtek

Do you know if the spring type seal is field convertable to th bellows?

See info at start of thread.

Steve

Hello

the o-rings that were used earlier were made of nbr
you should use for ***** hnbr now

regards and succes Art

Thanks Art that was most helpful.

Steve

Couple quick questions, We have RWF 316E Frick screws for our ammonia refrigeration. I've just started with the company this year and have inherited (4) 600hp units with chronic shaft seal problems and a system plagued with issues. So Im learning and attacking these one at a time. First question is does anyone have a general life expenctancy of a shaft seal? Does anyone have any background knowledge of these machines that may help lead to a solution, cause apparently our main service vendor has been working on this for some time and the people before me just throwing money at the problem, Id rather pay for a solution. Any thoughts? Any and all help is greatly appreciated!

Driz

There is published data about seal replacement times, i think it is about 20,000 plus hrs. i don't remember i am an exe and all my techs are out in field i will let you know.

We also had an issue with oil compatability-seal issues (Oring swealling) when we got that resolve seal life was much better.

There are many other issues that can affect seal life. US Icemanman is a site moderator who is very knowledgable in this area as well as those who have posted above.

Review info in previous post by others it is all great info