# Scotch Boiler Warm-Through



## Chillytoes

I have been trying to find some sort of schedule for warming through Scotch boilers. Preferably something more than it must be "done slowly", a statement surely open to any number of interpretations.
Of course the rate of firing will be dependent on such variables as the size of the boiler, whether there is any residual heat in the water, any method of positive circulation in use, type of fuel, etc, etc.

I have been through any number of books, including RN instructions, but nowhere can I find anything more than the most obscure mention of this important procedure. There is often some mention of the fact that forcing the boiler should be avoided at all costs but no definition of what would constitute forcing.

There's got to be a number of old steam men out there, so who told you blokes what to do? Who told you what rate to fire at and on what basis? 
How about telling me.


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## surfaceblow

The normal warm up procedure for a Scotch Boiler is a slow 12 to 15 hours to evenly warm up the boiler parts any faster the tubes would expand faster than the shell. You would increase the boiler pressure and water temperature by a slow firing rate then pull or bank the fire to hold that temperature until the entire boiler is evenly heated. Once the boiler is at 212 F you maintain that temperature without producing steam and hold that temperature for a number of hours before raising the temperature to the next level and so on. 

Joe


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## Basil

Only had a Scotch boiler on my first ship which was Diesel with all steam auxilliaries.

My ancient Tod & McGibbon's Elementary Q&A says:
At least 18 hrs to raise steam.
Water at bottom should be taken out by donkey pump and re-injected via the check valves or by using steam from the donkey boiler to operate the hydrokineter, if fitted. Also notes that the hydrokineter can pick up sludge from the bottom of the boiler and deposit same on heating surfaces.

Reed's Hints says at least 12 hours to raise steam and at least 8hrs from cold to pressure showing.
Light all fires going gently and circulate as above.
If an air cock is fitted on the boiler top, open and only close when steam is raised, air, of course, being harmful.


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## ARRANMAN35

Hi,
My experience is only with oil fired scotch boilers, the drill was to carry out the process slowly but continually until pressure was showing. small tips in the burners and they would be fired on a basis of 5 to 10 mins/hour rotating
furnaces starting with the lower centre one. Never had any problems with this method which had been passed down from older experienced steam hands.
A competent donkey man could with out recourse to manuals effectively carry out this procedure. Archie


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## Varley

I can't remember hearing 'hydrokineter' before.

Our dual pressure boilers had a heating coil fed from the other boiler (can't remember if this was from the primary/HP or not - presume so).


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## chadburn

I was taught and used this method myself, fire the wing furnaces first they also warmed the Boiler Shell and after a suitable period the centre. Nevertheless it is a slow process from cold hence the need for COSAG by the R.N.


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## Binnacle

After being laid up in the River Blackwater for months the tanker Polar Maid was raising steam to proceed to Preston to discharge her cargo of whale solubles. Additional crew joined including the master. The chief engineer and his engineers were in the process of raising steam, and after a day or two the after end of the ship was illuminated, however the bridge house remained In darkness and tilley lamps were still in use. As second mate I was keen to get the Brown’s gyro batteries charged up prior to sailing, so went along aft to find out from the C/E when we would get power amidships. It turned out that the newly joined master had ruffled old Wattie’s feathers by trying to impart a sense of urgency in the need to raise steam and get underway as we had to rendez vous with the Southern Harvester in Liverpool after Preston discharge. Wattie explained to me that he was “nae rushing his boilers for any man”. The boilers had been installed about forty years previous so his caution was understandable, he'd been on the ship for years.


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## Derek Roger

On Brocklebanks Maipura we had 3 Scotch Boilers each with 4 furnaces .
In port only one was in operation to supply steam to the deck gear and other services such as generators .
When in port with one boiler steaming the other 2 were kept warmed through by the hydro kineters . Getting ready for sea therefore only required about 4 to 6 hrs of building steam for the main propulsion at which time the va***e was raised in the condenser and the ship made ready . One watch required to the job under way .
The boilers were brought up to full pressure by rotating the furnaces with the very smallest tips until the boiler was warmed through.

At Stand Bye all the tips ( furnace injectors ) were replaced with the maximum sized tip.
|Control of steam demand was by a series of lights controlled from the E/R platform . Each boiler had four lights indicating how many furnaces were to be lit ; this was shown in the stokehold and the crew had to respond.

As I recollect the stokehold had a crew of 4 ; one fireman at each boiler and a Tindall overseeing operations .

At the boiler fronts during docking etc we had a fireman on each boiler monitoring and adjusting the boiler water level in each boiler 

The Engineers had to monitor and control all of that plus answer the telegraph and give the required movements .
Crew required was a total of 9 people including the oiler ( tail Whalla )
Happy Days Derek Never to be seen again .


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## Bob_F

*Weir Hydrokineter*



Varley said:


> I can't remember hearing 'hydrokineter' before.
> 
> Our dual pressure boilers had a heating coil fed from the other boiler (can't remember if this was from the primary/HP or not - presume so).


This was basically a circulator usually near the bottom of the boiler which was fed by live steam. When the steam was on, the boiler water was being circulated, normally the boiler wasn't fired until vapour or steam was coming from the vents. There is a good picture of this in Sothern's Verbal Notes and Sketches.
Bob_F


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## MWD

A proceedure I used very successfuly on twin burner vertical Cochran boilers and Babcock & Wilcox watertube units was to fire on one burner fitted with a small tip for about half an hour and then switch off and leave everything overnight for the boiler to naturally circulate and warm through throughly. Next morning the 8 to 12 could then put a small burrner tip in and fire continuously until the correct head of steam was reached and the unit ready for steaming.

MWD.


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## vectiscol

An interesting thread for a layman! The process seems quite prolonged compared to that of a steam railway locomotive. Was that just because marine boilers were much larger?


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## spongebob

Modern fire tube boilers based on the original 'Scotch Marine ' design have developed to a three pass wet back function but the start up water circulation problems remain and in most cases where a faster warm up is required thy are fitted with a low head external circulating pump that takes its suction from the bottom of the pressure vessel and discharges the water back into the boiler at the same level as the boiler feed water sparge pipe. 

Bob


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## chadburn

vectiscol said:


> An interesting thread for a layman! The process seems quite prolonged compared to that of a steam railway locomotive. Was that just because marine boilers were much larger?


Yes would be the answer I guess, mind you I have a warming up proceedure for my central heating boiler when Winter comes, I don't just bang the heating on!!


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## Chillytoes

Thanks for your interest gents. Every little bit of info helps. But I still find it difficult to understand why this very important subject received so little attention in the contemporary literature. Almost like some sort of ancient guild secret.

Thanks, Basil for your quote from Reed's Useful Hints. Even though I have a 1911 copy on my shelf, it was the only book I didn't look at. Murphy's Law in full flight! It's actually the only one I've come across which has anything like a schedule. Actually a very good and complete treatment.

One other thing I have wondered at is in relation to the hydrokineter. Would you have more than one fitted on a large boiler? And what would be the steam consumption of a hydrokineter? Never seen anything about that. And if it was used for about 6 to 8 hours during the warm through, what about the water level? How would all the steam in the form of valuable feed be recovered?


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## japottinger

Derek Roger said:


> On Brocklebanks Maipura we had 3 Scotch Boilers each with 4 furnaces .
> In port only one was in operation to supply steam to the deck gear and other services such as generators .
> When in port with one boiler steaming the other 2 were kept warmed through by the hydro kineters . Getting ready for sea therefore only required about 4 to 6 hrs of building steam for the main propulsion at which time the va***e was raised in the condenser and the ship made ready . One watch required to the job under way .
> The boilers were brought up to full pressure by rotating the furnaces with the very smallest tips until the boiler was warmed through.
> 
> At Stand Bye all the tips ( furnace injectors ) were replaced with the maximum sized tip.
> |Control of steam demand was by a series of lights controlled from the E/R platform . Each boiler had four lights indicating how many furnaces were to be lit ; this was shown in the stokehold and the crew had to respond.
> 
> As I recollect the stokehold had a crew of 4 ; one fireman at each boiler and a Tindall overseeing operations .
> 
> At the boiler fronts during docking etc we had a fireman on each boiler monitoring and adjusting the boiler water level in each boiler
> 
> The Engineers had to monitor and control all of that plus answer the telegraph and give the required movements .
> Crew required was a total of 9 people including the oiler ( tail Whalla )
> Happy Days Derek Never to be seen again .


Interested in the manning numbers quoted in the boiler room Derek. We had four Scotch boilers on SS Maihar two abreast and fronts facing each other, and only ever had two men in the stokehold. The feed water stop valves, and gauge glasses etc were all in the boiler room. The aftermost two boilers were arranged with backs to the engine room with a narrow cross alleyway(coolest place in the engine room!) and bulkhead and access doorway between boiler and engine room. Thus the fronts were unseen from us un ER but had repeat press. gauges on the ER bulkhead. .
Jim


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## Basil

> Thanks, Basil for your quote from Reed's Useful Hints. Even though I have a 1911 copy


Aahh, I have the much more up to date 6th edition - 1917


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## dannic

Went to college in 75, learnt about smoke tube boilers, warming through, gauge glass practice etc. knowing would never see them other than preservation jobs. Joined MT Oloibiri - 2 scotch boilers, Cochran Lamont as I recall, no worries about warming through, it was just a case of hiding from whichever piece of the uptake fell off next.
Dan


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## Varley

It would be interesting to know in what year "fire tube" (Father's vocabulary) became "smoke tube". Some bizarre early political correctness?


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## Peter Short

Here are the notes I made in the 1980's while studying for Third Marine ticket.

I think the problem is summed up on one of the attached pages thus:

_Because almost every surface of a scotch boiler is stayed, extreme care is needed in heating up. Steam must be raised slowly to equalise temperatures throughout the boiler to avoid excess stress._

_Also, 30-50 tonnes of water takes a long time to heat up._


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## david freeman

An interesting side line to this, is pressure testing a scotch boiler after major repairs. The furnace fronts off, then before the whole boiler was subjected to a pressure test: Then placed in the furnace was a wood fire to each furance to heat the water to blood heat, and allowwed to stand to permiate the boiler before the working pressure test was applied. At sea one would use feed water from the hotwell? would you not? before pressurising the boiler.


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## Peter Short

David,

Re. hydraulic testing of new boilers. While re-reading my notes, I noticed this:

_By using hot water in test, small leakages can be sealed by expansion, therefore cooler water probably preferred by surveyor._

I post this just as a point of interest, not trying to pretend I have any marine boiler experience.


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## eldersuk

david freeman said:


> An interesting side line to this, is pressure testing a scotch boiler after major repairs. The furnace fronts off, then before the whole boiler was subjected to a pressure test: Then placed in the furnace was a wood fire to each furance to heat the water to blood heat, and allowwed to stand to permiate the boiler before the working pressure test was applied. At sea one would use feed water from the hotwell? would you not? before pressurising the boiler.



This opens another can of worms. 

Using cold (ambient) water, at what pressure should a hydraulic test be conducted? 

I have heard some Chief Engineers state it should be no more than 10 psi.
On the other hand I have heard a Class surveyor insist on the full working pressure. Granted he was a 'makey learny' surveyor, but he WAS the surveyor - the guy who signs the paper.

Any thoughts?

Derek


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## david freeman

eldersuk said:


> This opens another can of worms.
> 
> Using cold (ambient) water, at what pressure should a hydraulic test be conducted?
> 
> I have heard some Chief Engineers state it should be no more than 10 psi.
> On the other hand I have heard a Class surveyor insist on the full working pressure. Granted he was a 'makey learny' surveyor, but he WAS the surveyor - the guy who signs the paper.
> 
> Any thoughts?
> 
> Derek


Alas my rule book and memory has me? Testing to the safe working pressure (design of The boiler), was done and is to test the shell Seams and straps with( Boilers With rivetted Joints), and the connections of the front and rear boiler face plates and the, combustion chamber, Furnace tubes connections/rivetted joints. This was true I believe for all designs of fire tube boilers. All welded seams and manufactured water tube boilers then one should read or is advised to read the CLASS requirements, and the regulations governing the class societies rules.


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## Chillytoes

To overcome the circulation problem when warming through scotch boilers, there were a number of methods, ruses, etc. used, most of which have been noted in this thread. But the one that I like was noted in an 1898 translation of a French author and I just have to quote it: 
"The circulators used at Indret by M. Garnier are thoroughly efficient. They consist of small centrifugal pumps, fixed outside the shells, which take water from the bottom and discharge it at a little below the water level. The pumps are turned by hand while raising pressure and are worked by steam when sufficient pressure is raised."
Worked by hand!!!? Who had that wonderful, satisfying and fulfilling job? The lucky bugger!


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## offcumdum sanddancer

To expand and agree with what others have said on this subject, here is what Jackson and Morton say in Reed's Steam Engineering Knowledge for Marine Engineers, first edition, 1969, says on page 40. (I have a first edition, apparently!!!)
(h) Connections are usually provided so that the boiler water can be circulated when raising steam. In fig 24a the boiler water is drawn from the bottom of the boiler through the blow down valve by means of the feed pump and delivered back into the boiler through the auxilliary feed check valve.

An alternative means of circulating is shown in fig 24b this is known as the "Weirs Hydrokineter", an auxiliary steam supply is necessary for its operation. The steam passes through the nozzle where it falls in pressure but gains in velocity, the steam flow then entrains water into the converging cones wherein the steam is completely condensed. A current of water is now circulating around the boiler and this enables steam to be raised more rapidly. When raising steam in a Scotch boiler care must be taken to ensure that the heating up process is uniform throughout the boiler otherwise straining of the boiler will take place and this could lead to tubes "springing" and subsequent leakages, in addition cracks could develop in the plating if the stresses are high. It is customary to take as long as practicable to raise steam and this may be as long as 24 hours if no circulation means are provided other than natural convection currents.

The Institute of Marine Engineers book, 'The Running and Maintenance of Marine Machinery, fifth edition, page 13, states that "Care should be taken to raise steam slowly and to tighten up manhole door joints as the boilers warm up. Steam at working pressure should not be raised on Scotch boilers in less than twelve hours (twenty-four hours is preferable)

As when I went up for my second's steam ticket I had no experience of anything other than watertube boilers and turbines and was all too aware that there was a certain examiner of engineers (Grant) in Newcastle who, I was lead to believe, was reputed to ask people like me questions about Scotch boilers and reciprocating triple expansion engines, I made sure that I knew as much as I could from sources like this.

Attached fig. 24 (a) and (b)


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## chadburn

It was indeed important to know about the older Engineroom equipment as that was the Examiners era, during my "run up" for my Ticket I made sure I had experience on some of the older vessel's including coal burners.


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## zebedee

vectiscol said:


> An interesting thread for a layman! The process seems quite prolonged compared to that of a steam railway locomotive. Was that just because marine boilers were much larger?


Hello Vectisol, a rather belated reply to your query. The long time is not due to difference in sizes, rather it is due to constructional differences. Scotch or fire-tube boilers have the furnace(s) surrounded by water and 
so the water beneath them is not heated uniformly. Locomotive boilers were/are water-tube boilers. In these the water is heated externally and thus uniformly, promoting more even circulation. I hope this brief explanation is of some help. Lionel
Ouch! Ouch!I am afraid I have made a very very basic mistake in stating that locomotive boilers are water tube ones. They most definitely are not, although the comments on differences in construction are true and these differences largely account for the disparity in time needed to raise steam from cold in these different types of boilers. There is a very good illustration of a Scotch boiler on Wikipedia as a first entry under Scotch boilers, there is an inferior illustration of locomotive type boilers also available. Please try and accept my unreserved apologies for my stupid mistake: it was not ignorance, just plain stupidity!


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## Varley

Amateur's question. Isn't heating of tubular furnace of fire tube boiler mainly radiant and therefore uniform WRT surrounding water?

From memory of Steambloc tubes mainly (exclusively?) above furnace so additional heat transfer from tubes would have been top only. I don't remember any circulating system (except to the waste heat / 'economiser') but then these were all auxiliary boilers).


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## baileysan

Scotch Boilers
The old story was rush them up at your peril. We used to start at least 36 hours before, longer if possible, and with small tips 10mins per hour then gradually increasing firing. Circulate from the bottome to the top .
Couple up with the Cochran so the SB was never pushed until really necessary. I sailed on many SB and fortunatley never had any problems.


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## spongebob

The original 'bread and butter' scotch marine boilers were coal fired and the low set furnaces had fixed fire grate surfaces that limited the primary heat release to the upper half of the furnace. This ensured a mass of 'dead' cooler water under the furnace that could only be moved by partial blowdown and/or slower conductive effect during the warm up period.
Modern fire tube boilers are still built but the designs usually involve higher mounted furnaces and a fire tube bank beside and under the furnace that promotes faster circulation and start up time. Circulating pumps that draw the boiler water from under the furnace flue and transfer it to just under the water level are often used .
Again the majority of these boilers are oil or gas fired and the furnace flue becomes a fully radiant heat transfer area.

Bob


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## spongebob

Varley said:


> It would be interesting to know in what year "fire tube" (Father's vocabulary) became "smoke tube". Some bizarre early political correctness?


A blast from the past David but my understanding that the fire tube was the furnace tube or primary heating surface and the boiler pass tubes were the smoke variety . The 'fire' has become very hot products of combustion by then but no longer flaming 

Bob


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## 76deemac

Chillytoes said:


> I have been trying to find some sort of schedule for warming through Scotch boilers. Preferably something more than it must be "done slowly", a statement surely open to any number of interpretations.
> Of course the rate of firing will be dependent on such variables as the size of the boiler, whether there is any residual heat in the water, any method of positive circulation in use, type of fuel, etc, etc.
> 
> I have been through any number of books, including RN instructions, but nowhere can I find anything more than the most obscure mention of this important procedure. There is often some mention of the fact that forcing the boiler should be avoided at all costs but no definition of what would constitute forcing.
> 
> There's got to be a number of old steam men out there, so who told you blokes what to do? Who told you what rate to fire at and on what basis?
> How about telling me.


It depends upon how close the rocks you are.


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## Peter Hewson

When surveying, on Hydraulic test, I would always ask for Working Pressure plus 10% or 10psi. unless the construction or repair specification had asked for another figure. I always had them done at "ambient" temperature. Right or wrong, I never had a failure. Raising steam the rule of thumb was 10Min/hr or 5min/1/2hr. until steam was seen and the cocks closed. Again never let me down in a 20 year career. Often took 2 or 3 days to get a Boiler back on line including the steam test, safety`s set. I signed a few off in the West Country. None to my knowledge have subsequently had problems that track back to my era.


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## Chillytoes

This thread has been very interesting. Much mentioning of the Weir's Hydrokineter, but as I was idly thumbing through Simpson's Naval Constructor there appeared in the back an ad for Eckliff Circulators. The ad says they can raise steam from cold to 120 psi in 45 minutes! Dr Google doesn't seem to be able to bring up an image or any details, so has anybody seen one or know something about them? (The book was printed 1914)


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## captainconfusion

With respect I suggest care in how you interpret your diagnostic of raising steam to 120psi, in 45 minutes. For instance what are you questioning, the design of the boiler, its manuafacture steam rating or is it a main plant or auxilary boiler.
Scotch boilers as per reeds and macgibbons, either as fitted a single boiler-Deep sea trawler, or as main propulsion for a main triple engine.bauu wak plant or as a pure steam turbine plant {reaction turbine] again on fresh water or salt water feed., While you are reading all these history books, are you the C/E oe 2/e who has something to comply with.
Or are you an a old land based steam plant. Here as in all cases you or one has to be responsible and read the makers manual, and comply within reason. ?????
You are asking the questions, why, are you running the plant as a responsible manger, or just shooting the breeze for a variation of plant you have no real knowledge of??? Hence the Certificate standards for engineers and classification societies in the marine industry, A scotch boiler for the main plant of a deepsea vessel is a potential bomb, if not treated with respect, The same could be said for a lancashire boiler as found in land steam plant


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## Chillytoes

Captain C
You seem to have missed the point entirely. I was intrigued by the startling claims in this ad and since I had never heard of Eckliff Circulators I thought perhaps someone on this site would know of them. This particular bit of kit was made by Eckliff Automatic Boiler Circulating Co. of 47 Shelby Street, Detroit Michigan and as already stated, the ad was circa 1914. Given my experience, 22 years at sea, Chief's Steam & Motor Certificate of Competency, my question is of mere professional interest. Isn't that what this site is about?


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## davidrwarwick

Here's the patent for Eckliff Circulator, read that for a description of how it works (or is supposed to):-


US1138864A - Circulator. - Google Patents




US939991A - Water-circulator for boilers. - Google Patents


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## captainconfusion

Thank you david, the many pages of information/patents etc, are enlightening. I apologise to 'CHILLY TOES' if I have appeared abrupt in my response to him.
This later information by David is varied both in designs/patents and years, and the 1914 reference 120psi in 45 mins, send shivers down my back.
I have attempted to read all the info on davids web site address, however I do not and still do not understand, without going back to college what this bit of ==kit== Does??? Is the flue circulation or boiler water circulation, and it drift into boiler supported by masonry,[Land based boiler scotch or lancashire] and his description of various water tube deigned boilers-NO Mention of design steam pressures or superheat temperatures, or rated out put.
As 'CHILLY TOES' states it needs understanding, and a simpler explanation of ==Eckliff Automatic Boiler Circulating Co. of 47 Shelby Street, Detroit Michigan and as already stated, the ad was circa 1914.===


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## Chillytoes

Dave,
Well spotted! A copy of the original patent application! I have printed off a copy and intend to read it all in due course. Just goes to show all this stuff is out there, you have to know how to find it.
In the meantime, I started this thread as a result of questions from a friend who is associated with a heritage vessel fitted with a Scotch marine boiler. His concern was the length of time specified for start-up and the need for volunteer(s) to be available for 24 hours or all-nighters. I was only aware of the hydrokineter for circulation, but since they only have one boiler, that was out of the question. So I suggested they fit a small electric pump drawing from the bottom of the boiler and returning to the top via, say, the donkey feed check or maybe the surface blow-off connection. (On page 151 of 8th Edition (1913) , *Sothern's Verbal Notes*..... shows a branch between the Bottom blow-off and the Ship's side blow-off which is marked _'Donkey suction pipe for circulating',_ so the idea is not original.) The pump was duly fitted and they were able to reduce the warm-through time, to their particular satisfaction. 
Here's the ad which started this discussion.


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