Previous in Forum: Hydrotest Temperature As Per UG-99(h)   Next in Forum: Radioactive Elements for Castings
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
18 comments
Rate Comments: Nested
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10

Pneumatic Leakage Crises

01/13/2012 11:04 PM

Dear TEAM

I am working on a project for a customer building equipments sourced with 125 bar pneumatic. We have used flareless (bite-type) piping. Fittings are rated for 300 bar.

We are facing a problem of leakage thru the fitting ends. The leakage occurs from portside as well as pipe side.

We attempted the following.

1) Re-tightening the fittings

2) Used teflon tapes on the threads

3) At some places we had the doubt of piping depth inside the fittings. So we replaced the pipes also.

Can our forum suggest some more tips on how to arrest the leakages.

We have a Coltri make compressor to generate pressure.

Thanks. Awaiting your support friends.
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
2
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33392
Good Answers: 1817
#1

Re: Pneumatic Leakage Crises

01/13/2012 11:22 PM

These can be tricky to work with, I prefer the flare type fittings which are much easier to work with if you ask me....That being said, I always finish the tightening the fitting under pressure just enough to stop the leak, the risk of overtightening seems to always be a problem with me, I guess I'm a little heavy handed at times...The tube end must be perfectly square to the seat, and the tube must be seated under force....The tube end must be perfectly smooth and clean, no scratches no residue..

__________________
 All living things seek to control their own destiny....this is the purpose of life
Register to Reply Good Answer (Score 2)
Go to Next Good Answer
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#2
In reply to #1

Re: Pneumatic Leakage Crises

01/14/2012 1:12 AM

Thanks for your prompt response....:)

We have a design constraint....We have to use flare-less type....We will surely check as per your suggestions....

But I need specific advise on how to arrest the leakages.... can i use sealant???

Thanks.....
Register to Reply
user-deleted-1105
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#3
In reply to #2

Re: Pneumatic Leakage Crises

01/14/2012 4:31 AM

"We have a design constraint".
I'd question where the 'design contraint' originated .
I often find such constraints are created out of thin air by someone who has no idea what they are talking about. When they are subsequently questioned they say things like "oh it doesn't matter I just thought it was a good idea". At which point the project resumes a sensible course.
Del

__________________
 health warning: These posts may contain traces of nut.
Register to Reply
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#4
In reply to #3

Re: Pneumatic Leakage Crises

01/14/2012 5:58 AM

We might have to agree to your statement...Bot would be unfair on us if we accept the flaw at this stage....anyways we as manufacturer are facing the problem and need to resolve this....We may try out using Parker E02 fittings...which may resolve the pipe side leakages but still the port side leakages will need to be addressed.. Please guide...
Register to Reply
user-deleted-1105
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#5
In reply to #4

Re: Pneumatic Leakage Crises

01/14/2012 7:06 AM

Sorry, it's not my field and I have no experience. I was only commenting on arbitary 'design constraints'
Del

__________________
 health warning: These posts may contain traces of nut.
Register to Reply
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33392
Good Answers: 1817
#6
In reply to #4

Re: Pneumatic Leakage Crises

01/14/2012 8:43 AM

What you're asking is how to do something improperly...While there may be some sort of sealant that would work such as "Leak tite", it's still a trial and error kind of thing...There is no proper way of doing something improperly...imo

__________________
 All living things seek to control their own destiny....this is the purpose of life
Register to Reply
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#13
In reply to #6

Re: Pneumatic Leakage Crises

01/18/2012 7:48 AM

We are eventually trying out a Parsons make anaerobic sealant....As an Engineer I fully agree to your say there cannot be a proper way way for doing things improperly....

I have also prepared test coupons of plumbings on Sandvik and Parker Tubes. Result will be known soon.....
Register to Reply
JayGeeBSE
Associate

Join Date: Mar 2009
Posts: 48
#7

Re: Pneumatic Leakage Crises

01/14/2012 8:57 AM

Talk to the fitting supplier. They have sold these things to do this job; it is their job to make them work. My experience has generally been they are keen to help. Everyone likes to be asked for advice and to show off their expertise.
Register to Reply
RAMConsult
Guru
Engineering Fields - Power Engineering - New Member

Join Date: May 2007
Location: NYC metropolitan area.
Posts: 3230
Good Answers: 444
#8

Re: Pneumatic Leakage Crises

01/14/2012 1:21 PM

You have not mentioned the piping material, are you sure it's compatible with the fitting? If the material is too soft for the bite mechanism it will slowly creep out as the bite pressure is increased, ultimately the mechanism will bottom out and the grip will continue to diminish, the problem is only made worse if there is a lot of vibration or movement at the fitting. As was previously mentioned the fitting manufacturer is the best guide for this phenomena.

__________________
 “Tell me and I forget. Teach me and I remember. Involve me and I learn.” Ben Franklin.
Register to Reply
3
Wal
Guru

Join Date: Jun 2011
Location: Phnom Penh
Posts: 4019
Good Answers: 102
#9

Re: Pneumatic Leakage Crises

01/15/2012 3:50 AM

What are the ferrule (aka bush, olive, sleeve...) and pipe materials?

Teflon thread tape is an excellent QA tool. If I see teflon tape anywhere other than on a threaded seal then I know it's been mal-assembled.

There are only two places these can leak. Between the pipe and the ferule and between the ferule and the seat.You can't tell which is leaking when it is assembled because the lock nut covers it. That's why you are seeing leakage form both ends. The thread on the locknut does not form a seal it only transmits the mechanical force to the mating parts. No amount of teflon will work.

There is normally a bearing washer between the nut and the ferrule so the ferrule doesn't bind and rotate with the nut. Are these properly installed?

If everything else is OK then a tiny amount of sealant on the ferule inside and on the seat may compensate for small voids(damage, material imperfections) that the ferrule won't squeeze into when tightened home by the nut.

Dirt and rough handling are not your friends when jointing.

__________________
 Difficulty is not an obstacle it is merely an attribute.
Register to Reply Good Answer (Score 3)
Go to Next Good Answer
jsmclaren
Member

Join Date: Feb 2011
Posts: 8
Good Answers: 1
#10

Re: Pneumatic Leakage Crises

01/16/2012 9:22 AM

What is the media in the pipe? What is the rate of leakage? What method have you used to confirm the location of the leak(s)? I am just trying to confirm you are chasing the right problem. My expertise is in leak detection, and, based on your answers I may have some suggestions that could help solve the problem.
Register to Reply
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#12
In reply to #10

Re: Pneumatic Leakage Crises

01/18/2012 7:44 AM

Media is Air....We use liquid soap method to check leakage...
Register to Reply
2
FredM
Associate

Join Date: Nov 2011
Location: Grand Rapids, MI USA
Posts: 29
Good Answers: 1
#11

Re: Pneumatic Leakage Crises

01/16/2012 12:10 PM

Good morning,

The other thing you need to examine closely is the actual assembly of the fitting to the tubing. One poster touched on this when he said that the tubing needed to be cut off square (NO more than 2* from square). You should also use a hack saw, not a tube cutter. De-burr the tubing lightly and make sure the end and the tube going into the fitting are clean and free of debris or defects. Next make sure you are assembling the fitting properly. Parker Ferulok requires the nut to be turned 1+3/4 turns from finger tight. EO and other brands may be similar. Consult your vendor or their web site for proper assembly procedures. You may also use a light oil on the threads of the body and nut to reduce friction. Mark the body and nut if necessary and count the turns. Do not re-use a fitting body to set multiple ferrules. You will never go wrong if you follow this procedure.

While I have never used Ferulok with air at such pressures, with hydraulics I have never had a leaky fitting at up to 400+ Bar when properly assembled.

And by the way, do not use teflon tape on the ferrule sealing portion of the assembly, period. You may use it on the port threads if you wish, but I would throw it away and use a quality non-teflon based pipe dope. Teflon tape properly or improperly used can shred and leave pieces that can move downstream and create trouble with other components, especialy orifices and the like.

I hope this helps. Please let me know if I can be of further assistance.
Register to Reply Good Answer (Score 2)
No more Good Answers. Go to first "Almost" Good Answer
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#14
In reply to #11

Re: Pneumatic Leakage Crises

01/18/2012 7:50 AM

Definately your sugesstions will help....Let me try out and let you know....
Register to Reply
FredM
Associate

Join Date: Nov 2011
Location: Grand Rapids, MI USA
Posts: 29
Good Answers: 1
#15
In reply to #14

Re: Pneumatic Leakage Crises

01/18/2012 12:55 PM

You are welcome Gajendra. If I can answer any questions or explain anything else let me know.

Also, I forgot to add this. Once the ferrule is assembled onto the tubing, if the fitting is disassembled, the correct procedure for reassembling and tightening is approximately 1/8 to 1/4 turn from finger tight. You will definitely feel the resistance increase as you tighten it. Over tightening, whether flareless bite or flare will result in deformation of the ferrule and tubing in a flareless bite-type assembly, or in a flare type the deformation of the flare seat on the fitting and even cracking of the flare on the tubing itself, none of which can be fixed by additional tightening! :)

Proper make-up is a major key to success.

Good luck!

Fred
Register to Reply Score 1 for Good Answer
No more "Almost" Good Answers.
pritam
Guru
Engineering Fields - Mechanical Engineering - New Member India - Member - New Member

Join Date: Aug 2008
Location: City of destiny, INDIA
Posts: 775
Good Answers: 67
#16
In reply to #15

Re: Pneumatic Leakage Crises

01/19/2012 6:27 AM

Dear Fred, GA to your both comments and congratulations for your first GA. It's really a nice answer, Mr. Gajendra will appreciate. A useful discussion for OP.
Register to Reply
FredM
Associate

Join Date: Nov 2011
Location: Grand Rapids, MI USA
Posts: 29
Good Answers: 1
#17
In reply to #16

Re: Pneumatic Leakage Crises

01/19/2012 11:24 AM

Thank you Pritam, I am honored. I hope the discussion will be beneficial to Mr. Gajendra and it will help him resolve his problems. I'm glad to be a part of the forum and able to contribute.

Have a great day!
Register to Reply
Gajendra.Gawand
Active Contributor

Join Date: May 2011
Location: Godrej And Boyce Mnf Co Ltd
Posts: 10
#18
In reply to #15

Re: Pneumatic Leakage Crises

01/24/2012 5:04 AM

Dear Fred,

Thanks for the valuable inputs. Our exhaustive investigations are pointing towards the Tube quality. It apparently seems the tube supplied were not of good quality. We investigated on the pipe metallurgy, finish...and the results were not matching to supplier claims... Now We have ordered tubes directly from Sanvik..

Presently we solved the problem by applying removable type sealant. For Threads SONLOK 3290 and for the bitting ferrule SONLOK 3638

But your insights will be very handy in putting back the things back in order.

Thanks TEAM.....
Register to Reply
Register to Reply
Have a Different Question?
18 comments

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

FredM (3); Gajendra.Gawand (6); JayGeeBSE (1); jsmclaren (1); pritam (1); RAMConsult (1); SolarEagle (2); user-deleted-1105 (2); Wal (1)

Previous in Forum: Hydrotest Temperature As Per UG-99(h)   Next in Forum: Radioactive Elements for Castings

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Mechanical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (100 right now)
Show Members
Advertisement