SWG 2

[Inchtain]

Good morning,

As it is known, most spiral wound gaskets problems occur during installation? Is is possible to use even adhesive drops to help install them?

Additionally, we have a heat exchanger cap where the gap between its flange and tube sheet flange and we did all the recommended installing steps for the gasket and we still have some leaks.

We though of installing a weld ring gasket. So, any information on this type and how to dismantle the cap in the future when we use such type of gaskets?

Thanks a lot

 

[SnTMan]

Cut the weld.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Inchtain]

Thanks SnTMan

By cutting the weld, does that affect the mating flanges? and is it possible to re-weld it?

Regards,

 

[SnTMan]

These are usually make up of two halves, each half seal welded to one flange face. At assembly the two halves are welded together, forming the seal.

Careful work can removes the two seal welds without unacceptable damage to the flange.

The weld ring gasket is not reusable, I'd think.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[SnTMan]

Inchtain, if you are not using inner and outer rings on your SWG you should consider it.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

@ photoInchtain
Can you send us more information?: diameter, pressure, drawing, PHOTO....etc.

May be incorrect secuence of bolts tensioning.

Regards

 

[mk3223]

IMO, it looks that there is a misalignment between the heat exchanger head and tube sheet.
May consider to perform a mechanical leak seal repair to stop the tube sheet leak as a temporary fix for operation. And then, plan a permanent repair with an equipment replacement.
And, consider to improve the SWG design per SnTMan suggestion, if not already done so..

 

[Inchtain]

Thank you for the informative replies.

Mr mk3223, what mechanical seals that can be applied?

Well, to extend the discussion beneficially, I am adding some details:

Mix feed (Tubes)/Dry Gas Exchanger (Shell)
Design Pressure (Shell & Tubes): 55.5 kg/cm2
Design Temperature (Shell & Tubes) 70 degrees Celsius
Diameter: 1478 meter
Shell Material and thickness: ASTM A 240 TP 304 (31 mm)
About 2mm gap only between the mating flanges of the channel camber and the tube sheet where we experienced leaks even we tried all proper installation procedures.

Currently, I'm afraid I do not have any photo or drawing for the equipment.

Thanks in advance for your continuous support.

Kindest regards,

 

[r6155]

@ Inchtain
More data: quantity, diameter and length of bolts
For 1478 mm diameter several mistakes can be made: incorrect gasket, pass-partition area no considered in calculations, improper installation and tensioning of bolts, weight of the channel, ........etc.

"we tried all proper installation", how do you know? Were you there during the test? Do you have enough experience for this test?. Sorry.

Try to check the calculations, something is wrong.

Regards

 

[mk3223]

Refer to the Vendor of the Leak Seal repair:

[link ]

https://www.teaminc.com/service-solutions/maintenance-repair/leak-sealing-repair

[/url]

 

[GD2]

Inchtain,
Heat Exchanger joint leaks are common. I also notice that you have only a 2 mm gap between the flanges which is not a huge concern for misalignment and bolting preload.
What is more noticeable to me is the process. You have a gas service.
The simplest way to look at it, is to doubt the gasket design itself.
if it is an old exchanger, the design technology has improved over period of time.
Contact the manufacturer and bring up the issue. They get feedback from customers like you from all around.
Thy may have changed the gasket design to jacketed, kamprofile etc. over the years. Kamprofile is very popular with gas service.

GDD
Canada

 

[Inchtain]

Good morning,

Here, I attached all the related data for the subject Exchanger.

Have a nice day

 

[BJI]

As it is known, most spiral wound gaskets problems occur during installation? Is is possible to use even adhesive drops to help install them?

Have you inspected the gasket, was it damaged during installation? You have a recess so likely adhesive is not needed but can be used sparingly if necessary.

Have you checked the surface finish and flatness in accordance with ASME PCC-1? There was no mention of your assembly bolt stress or procedure. There is nothing wrong with a spiral wound gasket, you should definitely not use a welded seal. What were the input parameters in your ASME PCC-1 Appendix O calculation to determine the bolt load? Have you tried contacting a bolting specialist?

 

[r6155]

1)No vent nozzle is on left channel, hence air is trapped during hydrostatic pressure test.
2)Bolt tensioner shall be used for stud 1 3/4”, required elongation must be controlled (no torque).
3)I insist, may be incorrect secuence of bolts tensioning

Regards

 

[Inchtain]

Is there a typical tension procedure that you have r6155?

 

[BJI]

Torque is used successfully everyday. What was the torque used and target bolt stress?

 

[r6155]

@ Inchtain-
Search in internet Hydraulic Torque Wrench and Hydraulic Bolt Tensioner

@ BJI-
Do you think that tensioning by torque for stud 45 mm (1 3/4")x 440 mm is a good practice?

Regards

 

[Inchtain]

Good morning,

Mr. BJI, Why cannot we uses a welded ring gasket? what are the cons from using it?
Anyhow, is it easy for anyone to do the calculations based on ASME PCC-1 Appendix? any clues?

I remember both torque and manual tightening were performed following a numerical sequence by a specialized company without success. However, I could not find the old used values.

Any idea on how to calculate the required tension or torque amount?

and which is the difference between the two procedures?

Thanks

 

[r6155]

@ Inchtain
Sorry, you are very confused.
Read (slowly) PCC-1 and try to understand.
Do you have the original design calculations?
If this HE was designed (year 1992) with SWG, why do you think you change to a welded joint? ......ummmmmm.
Search in your drawing information about torque value, lubricaction or elongation of bolts.

Regards

 

[Inchtain]

The heat exchanger was designed and manufactured in 1991.

No indication of the torque value, lubrication or elongation of bolts in its drawing and data sheets. To make things worse, the factory closed in 2011.

Regards,