Thermic Syphon

I completely agree with your last message Duncan - specially the second paragraph.

I suspect that the inspector from Jons original message was simply suggesting the removal of the combustion chamber along with the cross tubes. That won't affect the boiler integrity surely?

Also 'design changes' to a published design?? I haven't seen a model boiler drawing for 3 1/2" gauge that doesn't have some kind of recommended modification.

Phil H

I think it should be mentioned that the discussion with my inspector was more of an informal chat; I'm a while off boiler making yet. I am primarily trying to keep him involved at every stage both from the point of view of making sure I do things correctly and to enable him to sign it off with confidence when the time arrives.

It's raising some interesting points, I'll follow this with interest.

I realise that my question was parallel to the main topic, but ...

Jeff Dayman suggests that the term Thermic Syphon is used because that was the term on the patent. Well a patent cannot be had for an idea (etc) which is already well known and in general use. So, it cannot be the same as 'thermosyphon'. So why can no-one tell me what the difference is, please?

Regards, Tim

Wikipedia seems to cover it pretty well Tim, with Thermic Syphon describing a device and thermosysphon an effect. To be honest, the devices in LBSC's combustion chambers seem to resemble Galloway tubes rather than thermic syphons.

Looking up thermic syphons reminded me of Field boilers as used on fire engines and trams, where the tubes that project into the firebox have a concentric inner tube so that they draw in colder water by the thermosyphon effect. Going off-topic, do any models use Field tubes?

Brian

Thermo syphon was the term applied to the cooling system of the low powered vehicle engines preceding WW2, and immediately afterwards. Being of low specific power output, (Think Austin 7, Austin 10, Ford 8, Ford 10 etc).there was little need for a high volume (mass flow) of coolant to be forced around the engine, so there was no coolant pump. The coolant flow was derived from convection. The coolant, heated within the cylinder block and cylinder head, rose to the top of a tall radiator, where it was cooled by the air flowing around the tubes and fins. As it cooled, it increased in density, and fell to the bottom of the radiator. Convection then drew it back into the bottom of the cylinder block, ready to abstract heat and so cool the engine. And so the coolant circulated, slowly and steadily.

As engines became more sophisticated and and increased in power for their size, the greater heat rejection required higher mass flows, so a coolant pump became necessary, to prevent local hot spots, and to carry away the greater quantity of heat from the engine.

In VERY round figures, whatever power is available at the flywheel, a similar quantity goes into the cooling system, and has to be dissipated.

Howard

typo corrected

Edited By Howard Lewis on 19/08/2018 17:56:13

Hello Howard

If you read my message here dated 15/08 you will see that I have no difficulty with the thermosyphon idea. My question sought an explanation of what was special or new and so was called by the different term Thermic Siphon. And I have read the Wiki topic but the functioning of the device is not explained in a way that I can understand. My fault entirely, no doubt.

Regards, Tim

Tim,

It's probably all beyond my comprehension, but ... You may find it worth reading the eleven patents that feature the term "thermic syphon" in their title or description: **LINK**

https://worldwide.espacenet.com/searchResults?submitted=true&locale=en_EP&DB=EPODOC&ST=advanced&TI=&AB=thermic+syphon&PN=&AP=&PR=&PD=&PA=&IN=&CPC=&IC=

There are probably others, relevant, but that seems a good place to start.

MichaelG.

.

Edit: reduced the list from 13 to 11, by enclosing the two words within double quotation marks.

Edited By Michael Gilligan on 19/08/2018 18:32:14

Hello Tim,

Maybe the term "Thermic Syphon" was coined in the same way that "New Blue XXXXX" was the selling point for some apparently new detergent.

Many many years ago, a washing machine manufacturer produced one where "The Electronic Brain" was programmed by a large square "composite" piece with various slots cut into the edge.

The salesman was expounding the virtues of "The Electronic Brain" when I said, "A series of micro switches?"

"Er... Yes"

A well known fact can be dressed up in fancy language to confuse, or leave in awe, the uninitiated. (Look at the hype in some supposedly technical TV documentaries)

"Excreta Taurum, Erudite Vincit"?

Howard

As I read it a Nicholson Thermic Syphon (later shortened to thermic syphon) uses the same phenomenon as a thermo-syphon to circulate water but applied in a different way.

Cool water from the bottom of the boiler rises through a specially shaped tube inside the firebox that adds heat faster to the water by increasing the heating surface whilst also circulating water throughout the boiler to reduce scale formation and stressful temperature differences. The output of the syphon is designed to not splash water which would wet the steam. The physical construction of a Thermic Syphon strengthens the firebox and supports the crown and brick arch. There are other advantages. Much more to it than a basic thermo-syphon as used to cool an IC engine.

Physical phenomena cannot be patented, but Nicholson applied the thermo-syphon principle to a boiler with a novel construction, application and benefits that were patentable.

Nicholson had a number of original ideas and I guess he named his device for patent purposes in a way that indicated it was based on respectable scientific principles. It really works, at least in full size. He must have been a clever bloke.

Dave

Thanks, Dave - there at last - well done.

Cheers, Tim