Recommended clearance between shaft and packing ring (solid)?

[MechEngineer2012]

Hello everyone,

Could you provide the recommended clearance (min and max) between the shaft and the packing ring (solid ring made graphite)? We are transitioning from split packing to a solid one-piece design for a pump. As the packing will be compressed, we need to ensure that the clearance between the shaft's outer diameter and the packing's inner diameter is not too high. Are there standard clearances for this and could you please share them? Thank you.

 

[mfgenggear]

Please fund the o ring manufacturing design instructions.

 

[MechEngineer2012]

mfgenggear:

Thank you for replying. We are talking about compression packing though?

I found a resource below which sates other dimensions of stuffing box except the clearance.

https://www.klinger.dk/media/3263/design_selection_for_packings-uk.pdf

 

[MechEngineer2012]

Hello All,

could you kindly respond to this post by sharing your comments and any relevant information you may possess? I would greatly appreciate your response.

 

[TugboatEng]

There is no clearance between the shaft and packing ring. The packing ring is supposed to be compressed against the shaft and gland surfaces.

 

[Artisi]

Does the OP mean lantern ring?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[MechEngineer2012]

TugboatEng:

Certainly, I understand the functioning of non-metallic packing within the stuffing box inner diameter and the application of a packing gland to compress it, thereby reducing leakage. I am asking about the establishment of tolerance limits for both the stuffing box bore ID and the shaft outer diameter (OD). Achieving a precise, no-clearance scenario through machining is impractical. Therefore, it is needed to define acceptable upper and lower tolerance limits for both the shaft OD and stuffing box bore ID.

Artisi:
No, I am asking about packing which is usually cut and split in stuffing box and compressed using gland. In this case, it is solid.

 

[geesaman.d]

I'd be asking the solid ring packing supplier for their recommendations. My company uses braided packing so I suspect my regular fits may not apply here.