The Stoker's Catechism

by W. J. Connor

12. Question.—How would you prepare a boiler for the inspection of a boiler inspector?

Answer.—I would blow her right out, take off the manhole cover, take out the safety valve, take out all firebars and the bridge, take down flue-port brickwork, have the boiler and flues thoroughly cleaned and swept, have a lamp or candle ready to light, a hand hammer and chisel, or scraper, a pailful of clean water, and a wad of cotton waste. When the inspector arrives, he quickly dons his overalls; I hand him the light and the tools and waste, and he is into the fireplace in a jiffy; down the side flues, under the boiler, giving a whack with the hammer now and then, and scraping off any suspicious scale, etc.; and when he comes out, as black as any sweep, he slips out of the overalls, gives them a whack against the wall, folds them up tight, and crams them into the black bag; has a dive in the pail, and is soon ready to go off somewhere else. But he tells me something about the boiler before he goes—not to my discredit.

13. Question.—How do you proceed to get her to work again, and what materials do you use?

Answer.—I first proceed to build the bridge and flue-ports, put in the firebars, the thin bars at the sides; then I replace the safety-valve, taking care not to damage it or its seat, fill the boiler with clean water, put in the boiler the usual quantity of Naenaires Anti-Corrosion liquid, or the powder, make the manhole joint with plaited three-strand spun yarn and stiff putty (red lead and white lead) and lay the fire, which is done in this way: throw a dozen shovelfuls of coals towards the bridge, and to left and right of it till they reach near to the dead-plate, leaving the centre clear for the firewood; then throw in three or four shovelfuls of coals over the wood, with oily waste or paper in front, and she is ready for lighting, and the "fire is laid." The material for the bridge and the flue ports are firebricks and fireclay; these are rather expensive, but I learnt a wrinkle in the building up of bridge and flues. Through the frequent removals of these for boiler inspection and the hitting of the end of the long poker, several bricks were broken every three months, and I came to the decision to try stock bricks faced with fireclay as mortar; and I was more than satisfied with the result, and ever since then I used stock bricks and fireclay only.

14. Question.—How high should the top of the bridge be from the crown of the boiler or from the fire-tube?

Answer.—The bridge should be about nine inches from the crown of the fire-tube, if it were eight the draught would be curtailed, if it were ten the draught under the bars would be diminished, through much air passing over the bridge instead of under the firebars. As I had permission from my employers to build the bridge to the best advantage for myself in keeping up the steam, and having tried different heights for many years, I found that nine inches was the nearest to perfection. And in these experiments two additional bridges were built in one boiler; six feet behind the ordinary bridge was a concave bridge and six feet behind that was a convex bridge. The concave bridge was built close up to the bottom of the fire-tube, and resembled a small archway, and extended down to within nine inches of the bottom or shell of the fireplace; the convex bridge was built on the bottom of the shell and reached to within nine inches of the fire-tube. When the flame from the furnace shot over the ordinary bridge, it clashed down under the concave bridge, then rose up and swept through the convex bridge and away to the bottom flues; the object of these three bridges, in one tube and for one fire, was to keep the flame and heat in the boiler as long as possible, instead of the heat flying swiftly over the bridge and out of the boiler. This experiment seemed to answer very well, but as there were several other boilers connected with this one there was no opportunity of testing it correctly, but the three bridges remained established, and were frequently shown to engineers and others.

15. Question.—What advantage is there in having the blow-off pipe of a boiler entering it from the top instead of at the bottom?

Answer.—I am not aware of any advantage in it, but I am aware of a disadvantage in it, and it is this, that while the boiler is being blown right out for the purpose of cleaning, or other reasons, the stoker will often commence doing some other work, and in due course the boiler is filled up with water, and the fire lighted, and by-and-by the stoker comes to see what progress she is making; he looks at the water-gauge but sees no water in it because it has syphoned out of the boiler; at first the heated air pressed on the water and forced it through the blow-off pipe, and then the pipe became a syphon, and the pressure increasing as the water leaves the boiler, she is soon emptied, and if the fire is not raked out, soon burnt. Such a mishap could not happen to a boiler with the blow-off pipe at the bottom, for when the stoker blows out his boiler he must shut the cock before he can fill her, and when filled there is no chance of the water escaping out again.

16. Question.—Is there not some disadvantage in having the blow-out cock at the bottom of the boiler?

Answer.—Yes; the cock and pipe are subject to corrosion on account of water dripping down on them from the stoke-hold floor, as some stokers quench their clinkers and ashes while they are up against the front of the boiler, instead of drawing them forward a few inches from the front: and as the pipe is out of sight under the plates of the floor, nobody takes the trouble to lift them and examine—not only the pipe and the cock, but that part of the boiler where the water streams down from the drenched ashes so frequently. So there are disadvantages in both methods of blowing out the boiler, and always will be, until the stoker learns his business, and takes an interest in his work, not only for his own sake, but his employer's also.