SimonD’s workbench

[SimonT]

Simon,
As Graham said, there are various different vacuum pumps. These should not be confused the the Vacuum Ejector mounted on the driver's side of the firebox. Main differences are the size and mountings. All have the pepper pot (I'll stay with the popular name) although early engines such as some of the 4-4-0s had the pepper pot above the footplate. The large tank engines carried the pepper pot on the front of the drivers side tank.

Vacuum pumps were either hung off the frames or hung on the heavy framing that carried the hanging plate. viz.


My photo of the 42 in Steam. The vacuum pumps show up infrequently in Swindon GAs.

This is the vacuum pump in the 94. it is mounted onto the inside of the left frame. I've yet to add the pepper pot. I hope to do set of prints for the motion at some time in the future when my life calms down a bit.
A real 94 photo

Hope this helps.
Simon

 

[simond]

Thanks Simon, Jan, all,

It appears that there are different castings (length to suit the stroke) and it appears that the oil pot may be mounted directly or indirectly, and now, perhaps the pepper pot / limiting valve / adjusting valve may also be direct or remote as well. Try as I might, I cannot see a pepper pot on the photos of the 136x panniers, and as there must have been some kind of limiting valve, I conclude it was remote, possibly between the pump and the retaining valve & reservoir.

I have adjusted the CAD to make the rib flat-sided, I'll let Chris decide if he wants a pepper pot or not! The pipe is not modelled in the CAD as it is a bit of bent copper wire on the model...

The hanging bracket is still to be made.

 

[simond]

A remove makes my memory strained, but some GWR engines had both ejectors (large/small) and pumps. The pump was on the drivers side, I think between the first and middle axles. Linked to the crosshead, I seem to recall. It would take the place of the ejector once the loco was up and running. Vacuum (said in my head with an associated Midlands accent - 'Vacum' - as my footplate trainer worked out of Birmingham) could be maintained by the small ejector.

Origins of the Great Western Vacuum Brake

Introduction In the development of the locomotive engine the initial challenge was to make the machine go. Stopping was less of a pri...

janfordsworld.blogspot.com

Cheers

Jan

Jan,

thanks for this. What a most interesting lady!

Anyone with a few minutes to hand can learn a lot from that website. Fantastic!

cheers
Simon

 

[Pencarrow]

Confused, which bit are people calling a pepper pot? I assumed it was this part, but now think not...



More than happy with that CAD Simon. Make it so...

 

[Dave Holt]

That's the lubricator.
Dave.

 

[simond]

The pepper pot is much smaller and were it modelled would be between the oil pot / lubricator (circled in red) and the rear valve box, on top of the rib, which is actually a cast-in passage.

It’s brass, about 2” high, and an inch or so in diameter and has an array of holes (like a pepper pot) in the top to let excess vacuum out

You can see one in the lower picture in Simon’s post above. Like a brass test tube wrong way up.

 

[Dave Holt]

Simon.

Looking back at the more side-on photos (page 74), I agree that there is no visible vacuum relief valve. Perhaps, due to the short stroke (20" vs usual 28/30"?), there just isn't space to include the valve mounting on the pump body and so it is incorporated in the pipework, as you suggest.
Dave.

 

[Pencarrow]

Bit slow at the back of the class... This bit?

 

[simond]

yes, that's the baby.

dont worry, it took me a while too...

and that one has holes around the outside, like a poppy seed head, rather than in the top like a pepper pot, but don't let that bother you

Right, I have new 3D cad, so all I need to do is print it. And unsolder the pipe and resolder the pipe and figure out how to make the bracket.

That's the agenda for the next modelling sessions. Then the decoder and speaker and KA if I can.

Then...
drumroll...

 

[Pencarrow]

Pity I stupidly blocked off the void in the boiler, plenty of room there. Iirc, the weight is mainly in the side tanks.

 

[Dog Star]

Did you guys not follow my link to a photo of a pepper pot?

Never mind, you are now on the same page.

 

[simond]

Did you guys not follow my link to a photo of a pepper pot?

Never mind, you are now on the same page.

I did, Graham, but it confused me. My excuse was that rather than take my time, I read it in a hurried lunchtime and jumped, predictably, to the wrong conclusions - which were, to be fair, fuelled by the entire lack of pepper pots on the 1366 drawings & photos.

I think we have now concluded, as concurred by Dave Holt, that the limiting/relief valve was elsewhere, so Chris‘ loco shall have an oil pot, with the big top, and improved rib shape, but no pepper pot. I shall kick off the prints this evening.

so thanks to you, and to everybody else who contributed to the collective.

cheers
Simon

 

[Pencarrow]

Did you guys not follow my link to a photo of a pepper pot?

Never mind, you are now on the same page.

Yes but totally confused by the fact that the 1366 didn't visibly have one and then there were photos of locos that did visibly have one. Oh and it's Great Western... You wouldn't find strange things like pepper pots on Bulleids...

 

[simond]

Yes but totally confused by the fact that the 1366 didn't visibly have one and then there were photos of locos that did visibly have one. Oh and it's Great Western... You wouldn't find strange things like pepper pots on Bulleids...

Well, as is well known, GW locos are all the same

 

[Dave Holt]

You wouldn't find strange things like pepper pots on Bulleids...

Oh yes you would. Here's the brake ejector and steam brake valve (blowing steam rather badly) on 35006, P&O. The valve in question is on the bottom of the ejector, in the centre of the photo. Somewhat bigger than the item fitted to GWR vacuum pumps, but serving the same purpose.

Not sure of the origins of the photo but copyright to the 35006 P&O Society.
Dave.

 

[Pencarrow]

Well, as is well known, GW locos are all the same

Bit like their signal boxes... All standard... Found out the hard way when building this...

 

[Pencarrow]

Oh yes you would. Here's the brake ejector and steam brake valve (blowing steam rather badly) on 35006, P&O. The valve in question is on the bottom of the ejector, in the centre of the photo. Somewhat bigger than the item fitted to GWR vacuum pumps, but serving the same purpose.
View attachment 227026
Not sure of the origins of the photo but copyright to the 35006 P&O Society.
Dave.

Yes, but that's a proper Southern jobbie.

 

[SimonT]

jobbie

Bit harsh.

 

[simond]

Bit harsh.

Yeah, but at least it’s been polished

 

[3 LINK]

Yeah, but at least it’s been polished

I thought you couldn’t polish a Jobbie..