ASME B16.5 3" 600# RING JOINT DIMENSION UNCERTAINTY

[timsch]

I am reviewing a drawing for a 3" 600# RTJ VanStone thermowell. ASME B16.5, Table 5, refers to note 4 when sizing the ring gasket. It clearly states to use the #30 ring rather than the #31. However, when I consider the K_min dimension, I am uncertain whether to use the dimension that corresponds to the #30 ring, which would be 5.25" diameter, or whether to use the dimension that corresponds to the #31 ring, which would be 5.75" diameter. Initially, I thought that 5.25" would be the correct choice, but now that I see the actual part being made and how little material is left on the outside of the groove in the VanStone, I'm second-guessing myself. The reference to Note 4 is shown in the ring-selection part of Table 5, but not in the K-diameter part.

 

[SnTMan]

timsch, I am briefly looking thru an older version, but it looks to me like the 5.75" dimension (K) is tabulated (Table F5) for the subject flange.

Regards,

Mike



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

 

[timsch]

SnTman, looking at the note again, I see that it states "...ring and groove number R30 are used...", which does not specifically include the K-dimension. Looks like I've got some parts to scrap.

 

[SnTMan]

Ouch, sorry...

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

 

[DraftingMan]

timsch,

Are you using lapped flanges? Note 4 on Table 5 is only if you are using lapped flanges.​

John H. Dunten, CD
Certified Drafter

 

[LittleInch]

Interestingly, the table provides no K dimension for the R30 option(!)



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[timsch]

Yes, the VanStone thermowell uses a lap joint flange. The thermowell is machined from solid barstock and includes the stub end that the LJ flange slips over.

Table 5 has many instances where three dots are used rather than a dimension, which I take to mean that the previously indicated size is the one, similar to "ditto". The layout is a little odd, and the exceptions with note 4 tripped me up this time. A corresponding note in the K-dim section could have prevented my mistake.