TEMA type-P head - Packing Seating Stress

[Tomtation]

Hello

Does anyone have experience with TEMA P-type heads with external packing? I am wondering about:
1. what the initial seating stress should be.
2. how to determine the amount of torque on the bolts when assembling the joint.
3. how much force is generated due to the friction between the packing and the skirt of the floating tubesheet.
4. how to determine the minimum thickness of the packing box flange.

Any help, ideas or suggestions would be appreciated.

Regards

Tomtation

 

[SnTMan]

Tomtation, unfortunately, yes. I hate the d*mn things. However:

1 - typically pretty low values, struggled with this for years until I found something to hang my hat on. See attached from a Garlock handbook. Bottom line: m = 1.5, y = 3800. Lower values can be used if trying to justify a given bolting.

2 - see attached

3 - don't know, never cared. My guess is, negligable.

4 - packing boxes, glands, etc are generally designed per Appendix 2 as either loose or integral flanges, depending. This is where it is nice to have reliable m, y numbers. Note that facings are generally considered additive and can be pretty large.

Regards,

Mike

 

[Tomtation]

Thanks Mike. Some additional comments.

1. Since I posted that thread I've found the following paper online which gives some suggested values for y and an m=2.0. See attached file.
2. I find the required bolting to seat the packing is 40%+ higher than those given in TEAM Table RCB-5.22.
3. I've designed the packing gland ring and packing box based on pressure acting over the face of the packing contact area only since there is no hydrostatic end load. The flanges are still heavier than I expected due to the gasket seating condition. For example in Table RCB-5.22 it gives the minimum thickness as 1.125" but I'm calculating 2" based on a y = 2900 psi and m = 2.0 and a G=25.4375" for 1/2" square packing.
4. I suspect that the friction forces between the packing and floating tubesheet could be quite high which must be resisted by the gland bolts. Unfortunately TEMA does not address this.

Regards
Tomtation

 

[SnTMan]

Well, see, that's why I hate the d*mn things. Then they leak

Regards,

Mike