|
Post by runner42 on Aug 31, 2023 23:30:31 GMT
Thanks, but unfortunately we are not on the same page. both replies use the term 'body', is this referring to the regulator flange or the neck ring? My assumption is that the packing or O ring sits between the gland and the neck ring and bearing on the regulator rod, so for an O ring for example the gap should be 1/16" the width of the O ring.
Brian
|
|
|
Post by steamer5 on Sept 1, 2023 0:04:00 GMT
Hi Brian, The regulator flange will become part of the boiler, ie soldered in. The neck ring goes inside the regulator flange, with its flange hard up in the bottom taking up the 1/4 hole in the flange, guess it’s done this way so if you get wear in the neck ring it’s easy to replace, the O-Ring or packing comes next, followed by the gland, so yes your assumption is correct. The gland is then tightened down to put a little squeeze on what ever packing you decide to use to prevent leakage, the gland should not end up hard against the face of the regulator flange, his allows for adjustment of the packing if leakage occurs. When the gland flange ends up tight against the regulator flange, it’s time to replace your packing! You should be able to get 2 orings in for packing.
Cheers Kerrin
|
|
|
Post by runner42 on Sept 1, 2023 7:14:47 GMT
Thanks Kerrin for not loosing patience with me, but I have had a eureka moment today, that being I had incorrectly thought that the neck ring was the gland and the gland the neck ring. My initial post shows this error but was not picked up, which perpetuated a disconnect between your's and others advice and my understanding of this advice. However the residual concern is that with the gland when hard up against the regulator flange only provides a gap between the neck ring and gland of 1/64" or 0.1625", which is not enough for an O ring, yet you indicate two O rings are possible. So I am a little farther forward but still not there yet.
Brian
|
|
|
Post by steamer5 on Sept 1, 2023 10:49:09 GMT
Hi Brian, No problem, we are all here to share & learn! You don’t need the gland to be hard up against the regulator bush. I’ve been trying to find a reasonable picture but haven’t, but did find this… youtube.com/shorts/YnmsL3RflSQ?si=4Xxcwzj3j6GOb-QwIt’s a valve but the principle is the same. The person is adjusting the gland to stop the leak & you can see that the gland isn’t hard down, allowing further adjustment as required. When the gland does either get hard down, or adjusting it doesn’t stop the leak then the packing will need to be replaced. Hopefully this helps . Cheers Kerrin
|
|
mbrown
Elder Statesman
Posts: 1,720
|
Post by mbrown on Sept 1, 2023 13:07:49 GMT
Not sure if this picture helps - these are components on 99 3462. There is a fuller description in my thread. 20230219_160514 by malcolm brown, on Flickr - it shows the regulator rod with the stop silver soldered on. Above that L to R - quadrant which fits over the backhead bush; neck ring; PTFE tape packing (after it had been inserted and tightened up); bush that goes into the backhead bush which has the space for the gland packing and carries the gland studs; gland; handle. They are in the wrong order as the neck ring and packing go inside the bush before being tightened down by the gland. Looks like this when assembled... 20230219_164052 by malcolm brown, on Flickr Malcolm
|
|
|
Post by runner42 on Sept 2, 2023 0:24:49 GMT
Well it took some time to get there but this is it? Regulator gland by Brian Leach, on Flickr Just one more detail to cover. Is this type of gland packing suitable for O rings, because I thought that O rings should not be compressed and this design depends on compression to form a seal. Brian
|
|
|
Post by steamer5 on Sept 2, 2023 3:40:58 GMT
Hi Brian, You got it! Roger is the O-Ring expert. There’s, as always, an app for orings. Just had a look at the one I have, there must be a woops in it as it won’t do your size, even though it is within the range! Orings can be compressed, we have them at work sealing piston covers at way higher pressure than our boilers. I guess you are looking at 3/8 OD by 1/16 to give you rod size hole then the compression should not need to be much.
Cheers Kerrin
|
|
Neale
Part of the e-furniture
5" Black 5 just started
Posts: 279
|
Post by Neale on Sept 2, 2023 7:05:14 GMT
Would it be possible to machine a small step under the flange around the neck of the flange to set the compression on the O-ring when the gland fixing nuts are tightened while looking externally like a classic gland+packing arrangement? I.e. visually leaving small gap under flange.
Asks another Black 5 builder yet to reach this stage...
|
|
|
Post by ettingtonliam on Sept 2, 2023 8:01:37 GMT
Surely 3/8" OD x 3/32" if its to fit a 3/16" regulator rod?
|
|
|
Post by ettingtonliam on Sept 2, 2023 8:02:47 GMT
Would it be possible to machine a small step under the flange around the neck of the flange to set the compression on the O-ring when the gland fixing nuts are tightened while looking externally like a classic gland+packing arrangement? I.e. visually leaving small gap under flange. Asks another Black 5 builder yet to reach this stage... Sorry, I don't see the point of that.
|
|
|
Post by steamer5 on Sept 2, 2023 9:51:15 GMT
Surely 3/8" OD x 3/32" if its to fit a 3/16" regulator rod? Woops! Should have looked at the conversation chart, instead of relying on my best guess memory! Cheers Kerrin
|
|
uuu
Elder Statesman
your message here...
Posts: 2,813
|
Post by uuu on Sept 2, 2023 12:46:53 GMT
Because the nuts are not particularly tight, you might consider a lock-nut to hold them once you've got the amount of squeeze you want.
Wilf
|
|
|
Post by brucevoelkerding on Sept 2, 2023 13:07:40 GMT
Brian - a little more Information. A 3/16" ID x 3/32" wide x 3/8" OD O-Ring is specified as a "-106" (at least it is in the USA, here one calls it a "dash 106"). All O-Rings are molded from the same Molds. This means that different Compounds (Buna-N, Viton, etc) will have slightly different Dimensions post-molding. The typical Dimensions listed for O-Rings are the AN (average shrinkage) Rate post-molding. O-Ring dimensions are actually specified by ID and Width (cross-section) with the OD being a Reference Dimension. For a -106 : 0.174" +/- 0.005" ID 0.103" +/- 0.003" Width 0.380" (ref) average OD
|
|
Neale
Part of the e-furniture
5" Black 5 just started
Posts: 279
|
Post by Neale on Sept 2, 2023 13:53:08 GMT
Would it be possible to machine a small step under the flange around the neck of the flange to set the compression on the O-ring when the gland fixing nuts are tightened while looking externally like a classic gland+packing arrangement? I.e. visually leaving small gap under flange. Asks another Black 5 builder yet to reach this stage... Sorry, I don't see the point of that. There seems to be a discussion of traditional packing materials, in which case you lightly tighten the gland nuts enough to compress the packing to form a good seal and preferaby, as recently mentioned, use locknuts to stop anything moving. You can always retighten a touch if/when it leaks, until you run out of compression and then you strip out the old packing and replace. Or, you use an O-ring. These are designed to work with a specific amount of compression (depending on exactly what it is sealling against what?) in which case the gap between the end of the neck ring and the gland must be well-defined. Not depending on just how much you tighten the gland nuts. In a modern design, this would be set by just clamping up the nuts so all was correct, but as this is a traditional model, there should be a gap between the two flanges. How do you set this so the O-ring has the right amount of nip? Hence building in a spacer so that everything can be tightened without spoiling the appearance.
Personally, I would go for something that it is more difficult to assemble wrongly - I can imagine that if this were our club loco, some bright spark would come along and "I'll just tighten that - those nuts are a bit loose."
|
|
|
Post by ettingtonliam on Sept 2, 2023 14:56:47 GMT
You nip up the nuts until the O ring just doesn't leak?
|
|
Neale
Part of the e-furniture
5" Black 5 just started
Posts: 279
|
Post by Neale on Sept 2, 2023 18:31:40 GMT
One of the fun things about model engineering is that in any group of n model engineers, there will be n+1 conflicting opinions! So much depends on skills, experience, and knowledge (and where and how you gained them), plus materials and tools available. I'm the kind of model engineer who would rather sit in front of a CAD screen and then CNC machine a component than get out hacksaw and files... I'm sure that "nip it up until it stops leaking" would work, but my (purely personal) preference is to try to avoid that kind of approach. At the end of the day, all that really matters is how it behaves on the track. Pretty academic for me anyway - at current rate of progress, I won't be making these bits for another 10 years or so. All good fun!
|
|
|
Post by runner42 on Sept 3, 2023 8:47:44 GMT
There's some more information to take on board from the additional replies depending on how things progress from hereon. The basic premise is to tighten until the leak stops and if sucessful don't fix if it aint broke. However, there is another consideration, that being are we talking about a water leak and a steam leak? At the moment I am considering a water leak albeit a very small weep every 5 or so minutes between the regulator rod and the gland and occurs only when I operate from open to shut and vise versa. This is achieved by filling the boiler with water up to the top of the steam dome, which is quite a bit higher than the regulator rod and gland. The reason for this preliminary water test is so I don't need to close off the steam dome to enable a steam test to be undertaken. I am considering when using PTFE tape wether this benifits from some settling in with the temperature rise during a steam test will cause expansion to close off this occassional weep.
Brian
|
|
|
Post by britannia on Dec 12, 2023 16:20:14 GMT
Yes, a simple O ring does the trick in my experience
|
|