Can anyone explain the W1 Gresley water tube boiler?

[Simon Robinson 4Participant @simonrobinson4]

Hi

I've been reading about the LNER W1 Gresley water tube fire box boiler. Can anyone explain in simple terms how this worked? 

Also has this design ever been used in small scale coal fired live steam locomotives such as 5" gauge? Is it a complicated boiler to construct compared to traditional boilers? 

 

thanks

Edited By Simon Robinson 4 on 05/01/2018 17:21:13

[Simon Robinson 4Participant @simonrobinson4]

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Gresley water tube fire box boiler works same as Yarrow boiler.

**LINK**

[BazyleParticipant @bazyle]

It it just a yarrow boiler as used in ships. Instead of the fire going inside the tubes up the boiler it goes around a set of tubes that are carrying the water. Instead of the fire being enclosed by the water jacket of the firebox it has to be enclosed in a firebrick enclosure. Key point: fire outside tube instead of inside.

For convenience the tubes start off connected to a lower thick tube ("mud drum" and end in a big tube or thin boiler at the top. As the tubes are near vertical the hot water rises fast and this circulation is supposed to help heat transfer. There is a set of tubes and drum each side like a tent with the small collecting boiler along the ridge. The fire is in the middle.

This configuration can be lighter and there isn't a big body of water sloshing around in the big boiler cavity which is good for ships in a storm but less necessary for locos unless the track maintenance is rather bad.

Someone in the North London club has a very nice model in 3 1/2" which I think won a medal at the ME some years ago. edit I don't know if this model was a yarrow boiler just he loco was very nicely done.

 

Edited By Bazyle on 05/01/2018 18:04:14

[Neil WyattModerator @neilwyatt]

Google Briggs Boiler, much loved by Australians, easy to build and in practice they seem to work as well as conventional Boilers.

Neil

[richardandtracyParticipant @richardandtracy]

I can't entirely agree with Neil. They do not 'work as well as.. ' conventional boilers. There are significant theoretical advantages in efficiency, time to developing steam and weight saving. The theoretical advantages were not all realised.

With less water in the boiler for a given external volume they get to steam quicker. With the majority of the outer case lined with fire brick, the average temperature of combustion is increased, leading to a better theoretical efficiency. The water tubes have a larger surface area to volume ratio, so in theory the smaller quantity of water can heat up quicker. It is possible to ensure that cooler water is heated up by cooler gasses – increasing the efficiency compared to a more conventional boiler. Due to a lower mass of water, the boiler power to weight ratio can be increased.

In practice, it it difficult to get all the listed advantages in a size as small as a train, and the boiler requires even more active management than a conventional boiler. The reduced weight of the loco can have implications for the tractive effort. In ships these boilers had massive weight savings – though the effect was more power for the same weight rather than reduced overall boiler weight.

Regards

Richard.

[duncan webster 1Participant @duncanwebster1]

If I google Briggs boilers I get some with firebox sidewalls made from water filled tubes and some with firebrick. Is the a definitive description?

[Neil WyattModerator @neilwyatt]

Posted by duncan webster on 06/01/2018 00:20:58:

If I google Briggs boilers I get some with firebox sidewalls made from water filled tubes and some with firebrick. Is the a definitive description?

Both!

Essentially water filled tubes lining the insides of a firebrick box.

Neil

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