TEMA R : confined gasket 1

[pHreaC]

Does a CAMM-profile gasket require an outer ring to be confined?

Do I list it under the solid metal gaskets?

 

[SnTMan]

pHreaC, I don't believe TEMA would consider this gasket confined by adding the outer ring, I think a better practice would be to confine it with flange turns, see the left hand sketch of Fig. RCB 6.5. The bottom sketch refers specifically to spiral wound gaskets, which can be considered confined when a outer ring is used.

For use with piping flanges, I would use the centering ring and would not worry too much about whether it is considered confined or not.

A Kamm (CAMM) profile is a solid metal grooved gasket with a soft facing, typically graphite. I'm not sure what you mean by "list", but it does not use the m & y values of a flat solid metal gasket, but more usually they are supplied by the gasket maker. I have used the values for grooved metal gaskets from Table 2.5-1 in the past to insure more bolting than I would get using the gasket maker's m & Y which are typically pretty low.

Regards,

Mike

 

[doct9960]

pHreac,

It has been a while since I've read TEMA, so I may be wrong.

Confined gaskets, as the name suggests, are gaskets "confined" by grooves (i.e. flanges grooves, pass partition grooves).

Outer rings on Kammprofile gaskets just ensures proper gasket positioning on contact surfaces.

 

[pHreaC]

An outer ring is a way of confining a gasket. So if I were to use a spiral wound gasket and add an outer ring to it, it would be confined and ok with TEMA R.

The reason of the confinement is 'blow out' of the seal. I don't see how a camm profile would 'blow out'. Tema however specifically tells you that a solid metal gasket is considered not confined (blow out possible?!). Is a camm profile to be considered under solid metal gaskets or not? Is a camm profile without outer ring confined (inner ring is present and is used to align)?

Hope this clears out my question.

grtz

 

[SnTMan]

pHreaC, I suppose this is kind of a grey area, and sure, it doesn't seem likely a solid metal gasket would blow out (but see below), but for a typical body flange joint with a kammprofile gasket on a heat exchanger, I would omit the outer ring and confine the gasket with the flange turn.

If using pipe flanges for the body flanges I would add the outer ring more for centering than anything, and would not be too concerned as to whether the gasket was confined.

The TEMA rules are necessarily somewhat general. As for solid metal gaskets exiting the joint, condsider a 72" dia. x 1/4" wide gasket as compared to an 18" dia. x 1" wide. The former might want to be confined.

Regards,

Mike

 

[doct9960]

pHreaC,

An outer ring is a way of confining a gasket. So if I were to use a spiral wound gasket and add an outer ring to it, it would be confined and ok with TEMA R.

Spiral wound gaskets confined by grooves are okay for TEMA R, but spiral wound gaskets confined by stud bolts are NOT. Ask your shell and tube heat exchanger manufacturer. They should be able to explain what's required for TEMA R service. Also see page D-20 of the Garlock catalog below to distinguish what's confined and what's not...

http://www.tagteam.com/tt/sl.ashx?z=3327af57&dataid=55078

Is a camm profile to be considered under solid metal gaskets or not?

Kammprofile is not considered a SOLID metal gasket. It is considered a semi-metallic gasket because it has metallic and non-metallic components.

Is a camm profile without outer ring confined (inner ring is present and is used to align)?

A Kammprofile (whether it has an outer ring or not) is confined if it is contained in a groove. Most of the TEMA R STHE's I've handled (back in the 90's) had the gaskets confined on the OD, usually male-female types. I've never heard of a Kammprofile with inner ring.

 

[doct9960]

SnTMan,

I'm unfamiliar with the flange turn. Can you describe what it looks like or do you know if there are sketches available in the web? Can't wait for Monday to borrow TEMA from our heat exchanger guys and have a look at that Fig. RCB 6.5. My long weekend started today.

 

[gr2vessels]

Just a helping hand for your weekend (Happy 4th July!), RCB-6.5 sketch.
Cheers,
gr2vessels

 

[SnTMan]

doct9960, "turns" are just shorthand speak for the machined male-female steps as shown in the left hand sketch of figure RCB-6.5, kindly provided by gr2vessels.

My long weekend starts today, noon. Happy 4th to all.

Mike

 

[DG72]

See the TEMA interpretation below.

TEMA inquiry # RCB 6.5 (312):
"Will any gasket type which includes an outer metal retaining ring meet the requirements of a "confined gasket" between two raised face flanges, or must the gasket be spiral wound type? For example, would Kammprofile Style ZA or ZG, IDT Style WS3885-DB also qualify as "confined" type?"

TEMA response:
Although TEMA cannot address specific designs or trademark products, any gasket with a solid metal outer retaining ring that prevents a direct radial leak path to the environment in the event of gasket extrusion or 'blowout" meets the intent of the TEMA "confined" joint.

 

[pHreaC]

So an outer ring makes a gasket confined. But is it necessary to have on outer ring on a Kammprofile to be in compliance with TEMA R?

grtz

 

[SnTMan]

Well, I was not familiar with DG72's interp. It seems an outer ring on a Kammprofile will meet the "confined" requirement.

Thanks, DG72.

Mike