Leaking regulator rod

[runner42]

I am faced with a leak between the neck ring and the regulator actuating rod. The rod dia is 3/16" (0.1875") and the neck ring and gland holes are sized at a number 11 drill (0.191"), giving a 0.0035" clearance. My number 11 drill I subsequently found out to be 0.1925" giving a 0.005" clearance. This something I can correct, however the title 'gland' suggest that some form of packing is required, which is not shown. From the drawing can you suggest where the packing should go and what type would be useful.

For your information the gland (the smaller of the two) goes into the regulator flange first followed by the neck ring which is used ti secure the assembly to the regulator flange and backhead.

Brian


Regulator neck gland by Brian Leach, on Flickr

[chrisb]

The usual packing material would be graphited yarn packed round the regulator rod in the 3/8” bore and compressed by the gland follower(neck ring). I managed to pick up the leftovers of some 3mm square graphited PTFE valve packing before I left the power station in 2016

[ettingtonliam]

Surely the packing goes between the neck ring and the gland? In the old days we'd just have used graphite string, but shouldn't be any problem getting a 3/8" OD 3/16" ID O ring should there?

[uuu]

EKP supplies still list graphited yarn for sale - there are probably others too.

It often comes as square section - so the method is to cut two or more tiny lengths to go round your rod with as little gap as possible - a bit like a piston ring. And, as with a piston ring, you put them in with the gaps on opposite sides.

Wilf

[ettingtonliam]

Your drawing shows a small chamfer on the bore at the inner end of the gland. This helps to squeeze the graphite packing down on to the rod. Probably a good idea to chamfer the bore of the neck ring at the large end too.

[runner42]

Thanks for the replies, well spotted on the small chamfer on the neck ring. Unfortunately graphite yarn isn't readily available down under so an O ring would be an alternative. This requires a groove to sit in and would this be in the same place as the chamfer on the neck ring?

Brian

[steamer5]

Hi Brian,
Company local to me shows it as available. Not sure if the post internationally. They show it in 3mm either 1m or 8 m roll. A meter would last a long time.
The other thing you could try is graphfoil…. This stuff, cheap enuff, bet the postage isn’t! www.ceramaterials.com/product/graphite-tape-foil-crinkle-cut/

Cheers Kerrin

[mbrown]

For glands like this, I usually twist PTFE tape between my fingers into a string and pack the gland with rings made from that. It compresses down to fill the space fully and, if I remove it, comes out as a single piece as if it were solid PTFE. I have never had any leakage and it makes for very smooth operation of the valve or spindle.

Malcolm

[flyingfox]

Greetings, I have found that the method, mentioned by Malcolm (as above) works well, or you could even machine a solid piece of PTFE to fit, slightly compress it and that will work well, and last a long time.
Regard
Brian B

[ettingtonliam]

Aug 23, 2023 1:53:52 GMT runner42 said:

Thanks for the replies, well spotted on the small chamfer on the neck ring. Unfortunately graphite yarn isn't readily available down under so an O ring would be an alternative. This requires a groove to sit in and would this be in the same place as the chamfer on the neck ring?

Brian

If you can find an O ring 3/8" dia and 3/16" bore, it should just fit straight in and be clamped by the gland. No need for chamfers in this case. Just make sure the leg of the gland is long enough to compress the O ring.

[weary]

3/16" x 3/32" is a standard size in US, example.

Phil.

[jma1009]

Hi Brian,

If you would like some suitable stuff for stuffing the gland box on your regulator gland I will happily send you some via airmail.

Just as an aside, I totally ignored Don Young’s drilling sizes. For a ground stainless regulator rod that you have presumably ‘miked up’ (it may not be exactly dead on 3/16th) I would centre and drill the bush No.13 with a drill from my brass set, and then ream it 3/16” bore. I have a number of 3/16th reamers, and I can choose one to suit the size and finish of the rod.

It’s a rod that principally turns in it’s bearing bush and gland. The packing shouldn’t be there to take up slack of a No.11 drill. Drill it undersize, then ream it for a proper bearing fit.

Cheers,
Julian

[ettingtonliam]

I'd agree with Julian. Ignore what DY says about drill sizes, drill and ream so its a close fit. 5 thou clearance on a 3/16" regulator rod is too much to rely on the packing, string or O ring, to take up. Rat up a drain pipe springs to mind. Don't want any chance of a steam leak through that gland just where your pinkies are going be, do you?

[runner42]

Aug 23, 2023 22:13:23 GMT jma1009 said:

Hi Brian,

If you would like some suitable stuff for stuffing the gland box on your regulator gland I will happily send you some via airmail.

Just as an aside, I totally ignored Don Young’s drilling sizes. For a ground stainless regulator rod that you have presumably ‘miked up’ (it may not be exactly dead on 3/16th) I would centre and drill the bush No.13 with a drill from my brass set, and then ream it 3/16” bore. I have a number of 3/16th reamers, and I can choose one to suit the size and finish of the rod.

It’s a rod that principally turns in it’s bearing bush and gland. The packing shouldn’t be there to take up slack of a No.11 drill. Drill it undersize, then ream it for a proper bearing fit.

Cheers,
Julian

Hi Julian,

thanks for the kind offer. I have taken your advice and reamed the new neck ring and used bronze instead of LG2. It's a very good fit. An O ring is the first try, but I don't know what compression is advisable if any. Teflon tape is readily available and I shall use that if the O ring does not perform.  

Brian.

[runner42]

Aug 24, 2023 11:08:27 GMT ettingtonliam said:

I'd agree with Julian. Ignore what DY says about drill sizes, drill and ream so its a close fit. 5 thou clearance on a 3/16" regulator rod is too much to rely on the packing, string or O ring, to take up. Rat up a drain pipe springs to mind. Don't want any chance of a steam leak through that gland just where your pinkies are going be, do you?

You are so right.

Brian

[runner42]

What did DY intend when designing the neck ring and gland? Looking at the drawing the gland 3/8" dia is 5/16" - 13/64" = 0.1094" wide and occupies this space in the regulator flange. The neck ring 3/8" dia is 3/8" wide and occupies this space in the regulator flange. The regulator flange 3/8" dia bore is 1/4" + (7/16" - 3/16") = 0.5". Change from fractions to decimal. So the gap between the gland and neck ring is 0.5" - (0.375"+0.1094") which is 0.5"- 0.4844" = 0.0156". This isn't enough for an O ring, but is it enough for say PTFE tape or is a wider gap required by removing some metal from the neck ring?

Brian

[ettingtonliam]

Where do these dimensions come from? They don't seem to tally with the drawing in your first post. Especially, the neck ring in your drawing only occupies 7/64 of the 3/8" bore, the rest fits into the 1/4" bore. Anyway, glands don't normally fit into their bores right up to he flange, theres usually a gap between he gland flange and the body flange, to allow for future adjustment as the packing 'settles in'

[runner42]

Aug 31, 2023 6:58:48 GMT ettingtonliam said:

Where do these dimensions come from? They don't seem to tally with the drawing in your first post. Especially, the neck ring in your drawing only occupies 7/64 of the 3/8" bore, the rest fits into the 1/4" bore. Anyway, glands don't normally fit into their bores right up to he flange, theres usually a gap between he gland flange and the body flange, to allow for future adjustment as the packing 'settles in'

We are saying the same thing your using fractions 7/64" and I am using decimal 0.1094". So the gap between the neck ring and gland is still 0.0156". The question is what gap is required say for an O ring and or PTFE tape? If reduction is required what part should be reduced to accomodate the selected form of packing?

Brian

[steamer5]

Hi Brian,
Looking at the gland design, you could quite easily have an 1/8” gap & O-Ring or packing to fill it. Like ellingtonliam says above the gland isn’t normally pulled down tight on the flange. In industry if a gland packing gets down close to having the flange down tight it will get repacked, doing so is usually not done with the equipment on line unless the pressure is low!
If you are interested I have a day off tomorrow & can find out what the 3mm graphite packing is worth?

Cheers Kerrin

[ettingtonliam]

Nothing needs to be reduced. You are assuming that the gland is pulled up tight to the body. It isn't, so you've plenty of room for an O ring or soft packing, whichever you choose.