Top up valves and anti-vacuum valves.

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Boustrophedon
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Top up valves and anti-vacuum valves.

Post by Boustrophedon » Wed Aug 23, 2017 7:38 pm

I have a Cheddar Samson with a top up valve and an anti vacuum valve, now both of these do the same job; they let stuff in and don't let stuff out.

So why do you need both? Surely a anti vacuum valve could be made to allow filling through it?

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Gralyn
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Re: Top up valves and anti-vacuum valves.

Post by Gralyn » Thu Aug 24, 2017 9:08 am

Isn't the anti vacuum valve (snifting valve?) in the live steam line after the regulator and the top up valve only in the boiler before the regulator?.
Regards Graham.

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Boustrophedon
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Re: Top up valves and anti-vacuum valves.

Post by Boustrophedon » Thu Aug 24, 2017 10:14 am

Gralyn wrote: Thu Aug 24, 2017 9:08 am Isn't the anti vacuum valve (snifting valve?) in the live steam line after the regulator and the top up valve only in the boiler before the regulator?.
Nope, one is on the boiler the other is on top of the sight glass fitting.

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f.schulz
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Re: Top up valves and anti-vacuum valves.

Post by f.schulz » Thu Aug 24, 2017 9:05 pm

The top up valve over the sight glas seems to be be an additional mounted tune up part. As I know was this not ex works.

Its function beside feeding is to rinse free the sight glass for better function during water feeding.

Regner use this technology since a long time very successfull in there 4mm sight glasses by feeding the boiler in this way.

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Chris Cairns
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Re: Top up valves and anti-vacuum valves.

Post by Chris Cairns » Sun Sep 03, 2017 12:01 pm

f.schulz wrote:The top up valve over the sight glass seems to be be an additional mounted tune up part. As I know was this not ex works.
That's how Regner do it.

A goodall type water filler valve was included with most Cheddar Models locomotives, but was fitted into a spare boiler bushing, not on top of the sight glass.

The Cheddar Samson was not supplied with a vacuum relief valve (I do not have one on my Samson nor my Iver, but have one on my Cheddar/GRS tram), and with no spare boiler bushing owners have had to resort to fitting it on the top of the sight glass.

The Cheddar Models vacuum relief valve uses a ball internally so you would have to modify the bottom seat so that you could still pump water through the valve past that ball, and that would surely only work with no boiler pressure?

Chris Cairns

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