Talk:Superheater

Damper vs front-end throttle

Based on my reading of the article, the damper and the front-end throttle appear to counter-act each other. The damper seems to lock steam out of the superheater when the throttle is closed, to prevent the superheater parts from overheating, while the front end throttle seems to keep the steam in the superheater when the throttle is closed - wouldn't this reproduce the problem that the damper is meant to eliminate? Or, if the damper closes first, wouldn't the superheater tubes be empty of steam, eliminating the usefulness of the front-end throttle? --Badger151 (talk) 19:01, 14 January 2010 (UTC)

The damper acts on the flue gases outside the superheater elements, not on the steam inside them. Biscuittin (talk) 20:00, 20 June 2012 (UTC)

One thing puzzles me about the Front-end throttle - what about burst superheater elements? Normally, the escaping steam can be shut off by closing the regulator (throttle). With the Front-end throttle this would not work. Is there an emergency stop valve? Biscuittin (talk) 20:43, 20 June 2012 (UTC)

Power plant boilers

I would like to propose that this is added at the bottom of the main/intro section for the article

Superheaters are also commonplace within power plant boilers for exactly the same reason. However, they are prone to blocking with ash. In many cases standard steam soot blowers struggle to keep this area free from ash build up and now new techniques such as cleaning using sound waves using sonic soot blowers are being employed.

Collieman (talk) 15:47, 14 April 2011 (UTC)

Unreferenced and possible COI issues. Andy Dingley (talk) 16:38, 14 April 2011 (UTC)

Citation tag added

I think this is dubious so I have added a Citation Tag:

"Another benefit of the front end throttle is that superheated steam is immediately available. With the dome throttle it took quite some time before the super heater actually provided benefits in efficiency. One can think of it in this way: if one opens saturated steam from the boiler to the superheater it goes straight through the superheater units and to the cylinders which doesn't leave much time for the steam to be superheated. With the front-end throttle, steam is in the superheater units while the engine is sitting at the station and that steam is being superheated. Then when the throttle is opened, superheated steam goes to the cylinders immediately".

The delay would only affect the first few piston strokes so, in my judgement, the effect on thermal efficiency would be negligible. Biscuittin (talk) 20:09, 20 June 2012 (UTC)

High Pressure Steam Only Goes One Way?

I'm totally missing why the superheated steam doesn't expand back from the superheater into the steam dome and elsewhere. I'm assuming that the superheater is being fed continuously from the steam dome and throttle. Why doesn't the superheater feed backwards as well as forwards into the valves and cylinders.Longinus876 (talk) 04:48, 16 November 2013 (UTC)

The purpose of a superheater is to raise the temperature, not the pressure. As you note, obviously the mass flows from the high pressure to the low pressure portion. However Pascal's principle only applies statically, not dynamically. When the regulator/throttle valve is open and the engine is allowing steam to expand through it, there is a pressure gradient across the superheater connected between them. As even a wide-open regulator still has some throttling effect, the pressure downstream of the regulator valve is lower than that before the valve.

This usually becomes clearer if you can find annotated diagrams of a powerstation or ship, with turbines and something like a once-through Benson boiler. Locomotives weren't always as clearly, or as efficiently, segregated. One of Stanier's was over-superheated to such an extent that the last part of the superheater is thought to have been losing heat to the exhaust gases. It would have worked better with a slightly shorter superheater. Andy Dingley (talk) 13:20, 16 November 2013 (UTC)

I'm sorry, was that English you were speaking?Longinus876 (talk) 04:14, 17 November 2013 (UTC)

So the pressure is still higher at the steam dome than in the superheater? Does that sound right? I think I see what you're saying. Thank youLonginus876 (talk) 14:21, 18 November 2013 (UTC)

I've never yet seen a positive contribution from you, so after this I just don't give a damn whether you understand it or not. Andy Dingley (talk) 18:49, 18 November 2013 (UTC)

Who told you that you own Wikipedia. You're a hostile piece of shit and should be thrown off the site. ESaD Longinus876 (talk) 14:04, 22 December 2013 (UTC)

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British shunters?

"An exception was shunting locomotives (switchers). British shunting locomotives were rarely fitted with superheaters" So, are we claiming that British as opposed to American shunters rarely used superheaters? As far as I know, small locomotives such as shunters and often narrow-gauge units rarely used them in either country, so I don't see why it specifies British shunters. I suspect the same applies to locomotives around the world, for that matter. In fact, I notice all the examples in the article deal with British railways and British locomotives. There are no examples available of superheaters in service in the US, and their findings on the efficiency matter? I've seen tags claiming that articles focus excessively on an American point of view, but is there one for other countries as well?.45Colt 15:30, 14 August 2014 (UTC)

@.45Colt: It's easier to prove a positive than a negative. If we have sources that are purely about British locos, and they say that superheaters were rarely used on shunting engines, we can infer that British shunting locomotives were rarely fitted with superheaters. But we cannot use those sources for practice in any other country. If we find a book about American locos, and it also says that superheaters were rarely used on switchers, we can then infer that American switchers were rarely fitted with superheaters; but again, this does not indicate what was done in other countries. Ideally we would locate a book that describes different practices in various countries; but although books with titles like "Steam locomotives of the world" exist, these are often picture-heavy and don't go into technical details, except in the cases of the unusual and curious: rack locos in Switzerland, for example.

As regards tags, you're probably thinking of {{Globalize/US}} or {{Globalize/North America}} - these are part of a whole series, and then there is the generic {{globalize}}. --Redrose64 (talk) 17:53, 14 August 2014 (UTC)

I've got a book here somewhere that says the same thing about American shunters. It's a very technical book; I'll see if I can't find it in the mess somewhere..45Colt 14:02, 16 August 2014 (UTC)

The first practical superheater???

The first practical superheater is stated as dating from the 1880s and 1890s. Whilst this may be true for steam locomotives, SS Carnatic (1862) relied on "a considerable degree of superheat" in order to achieve good fuel efficiency from her compound engine. This quote is from:
Jarvis, Adrian (1993). "Chapter 9: Alfred Holt and the Compound Engine". In Gardiner, Robert; Greenhill, Dr. Basil. The Advent of Steam - The Merchant Steamship before 1900. Conway Maritime Press Ltd. pp. 158–159. ISBN 0-85177-563-2.
Carnactic's superheater would appear to predate the mention in this article by almost 20 years. I suggest that some sort of correction or further research is needed on the early history of the superheater. ThoughtIdRetired (talk) 19:32, 24 September 2014 (UTC)

Rename to locomotive superheater or cover non-locomotive superheaters ?

Simpler IMO to rename this to superheater (locomotive) when we have sufficient non-locomotive content for a separate article ? - Rod57 (talk) 13:18, 5 November 2015 (UTC)

The ideal scope would still be superheater though, and the thermodynamics remains the same. The biggest difference is likely to be locomotive superheaters vs. compounds and turbines. Loco superheating appears around 1900, at just the time that the new electricity plants are starting to move towards turbines. We need a strong split by sections, but I don't think it's enough to justify splitting. Andy Dingley (talk) 13:43, 5 November 2015 (UTC)

In the UK, compounding generally didn't fare well (witness all those Webb and Worsdell compounds rebuilt as simples by their successor CMEs), but superheating did. Indeed, the most successful British compounds were also superheated. --Redrose64 (talk) 15:17, 5 November 2015 (UTC)

No, compounding was standard practice for most industries. Don't confuse steam engines and steam locomotives. Andy Dingley (talk) 23:00, 5 November 2015 (UTC)

I'm not. I was responding to your phrase "locomotive superheaters vs. compounds". --Redrose64 (talk) 23:41, 5 November 2015 (UTC)

Temperature

How is it possible to write an article on "superheaters" in locomotives without mentioning an operating temperature? Superheated connotes a very large range. Wikibearwithme (talk) 02:49, 16 March 2017 (UTC)

There wasn't an operating temperature, as such. In locos, all that "superheated" means is that the temperature of the steam was raised above the boiling point for a given working pressure. It might be only a few degrees; the aim was to extract further energy from the hot flue gases and so improve efficiency. --Redrose64 🌹 (talk) 08:42, 16 March 2017 (UTC)

The point is to raise the steam temperature, providing more efficient expansion in the cylinders. The effect of "energy for free" from flue gas heat is secondary.

Superheaters, outside railways, have a designed operating temperature and will be carefully maintained at it. The "850 / 850" naval boiler standard for one. Railways see varying loads on a small boiler so can't maintain such things as constant, but there is a design temperature and the French fitted pyrometers to express locos. Andy Dingley (talk) 11:12, 16 March 2017 (UTC)

Create 'Desuperheater' article as well?

I'm not the person to do it (don't understand all the wiki stuff), but I think it would be great to also mention desuperheaters and link to/create an article called 'Desuperheater'.

Also add language links?

• oververhitter = superheater (nl:Oververhitter <> Superheater)
• stoomkoeler = desuperheater

M.J.W.B. (talk) 10:25, 5 July 2023 (UTC)

@M.J.W.B.: Do uou have any sources? --Redrose64 🌹 (talk) 21:32, 5 July 2023 (UTC)

Sorry, no! Just working on a patent translation (Dutch into English) and am researching these terms. M.J.W.B. (talk) 08:52, 6 July 2023 (UTC)