The Stoker's Catechism

by W. J. Connor

22. Question.—What would be the consequence if the steam cock of the water gauge was choked, while the water cock was clear, or vice versa?

Answer.—The consequence would be most serious for the boiler, as the water would be forced up into the glass by the steam under it, and would make it appear as if too much water was in the boiler, and the stoker would proceed in the usual way to blow out some of this, apparently, surplus water; and then watch to see it come down to the working level in the glass, but he watches in vain—it will never come down. He might empty the boiler dry, and the water in the glass will be there as long as a breath of steam remains in the boiler to keep it up. And in the event of the water-cock being choked while the steam-cock was clear the consequence would be equally dangerous, for the water that was in the glass before the stoppage occurred would remain in it, for the stoppage would not allow it to drop down into the boiler again; so there it would remain, and when the stoker came round to look at his boiler, unless he happened to notice that no movement of the water was visible, he would pass on without further ado, and remain in total ignorance of his danger. Hence the necessity for the stoker to blow out his water gauge every time he comes in front of his boiler, and if the water enters the glass in a sluggish or dilatory way the cocks need to be cleared of the partial stoppage, and let the water enter the glass with a rush.

23. Question.—Could a boiler collapse without affecting the fusible plug?

Answer.—Yes; the tank that supplied the boiler with water leaked badly, and to stop the leaks a quantity of fine oatmeal was mixed with water and poured into it, and in due time reached the boiler; but instead of the oatmeal permeating the whole of the water in the boiler, it never got beyond the parts surrounding the fireplace; it stuck on the sides and top thickly, and was baked hard on them. After a few days the sides of the fire-tube bulged inwards nearly twelve inches, and the boiler had to be stopped and blown out, and the fusible plug was found to be unaffected—it was one selected by a Boiler Insurance Company, who had to repair this damage, and the stoker was exonerated from blame, but there is little doubt that if the plug had leaked the mishap would have been attributed to shortness of water and the stoker would be blamed for what he did not do, and get the sack into the bargain.

24. Question.—Why is it that an injector can force water into a boiler from which the steam comes to work the injector at a greater pressure than is in the boiler?

Answer.—The secret of the working of the injector is due to the velocity of the steam issuing from the point of a conical tube, and water issuing from another conical tube somewhat larger than the steam cone, and a partial vacuum created in the barrel by the steam and cold water meeting—as both cones face each other. The cones are about four inches long, one and a quarter inch wide at the mouths, and about one half of an inch at the points. The suction pipe, steam pipe and delivery pipe are about one inch diameter, and the overflow pipe half an inch diameter, and the water tank three feet below the level of the injector, the space within the barrel might be twelve square inches; the water and steam cocks are supposed to be always open, and this is how the injector is started working. The water-wheel is turned partly round, and a figured disc behind it indicates the quantity of water let into the barrel, while the steam is let in by turning a wheel attached to a quick-screw spindle; then there are ructions inside—the steam and water have come together, and the water overflows through the half-inch pipe; but by a little manipulation of the water, air will soon start it working; then the overflow ceases, and the air rushes into the pipe and hums, and the injector is working. And the reason of its working is, in my humble opinion, the concentration of water and steam, with the vacuum thrown in, that gives additional pressure to the water in the injector. I might venture to say it gives fully ten lb. on the square inch over and above the pressure of steam within the boiler.

25. Question.—The noise created by the injector while working being very objectionable, could it be mitigated? And, if so, how?

Answer.—Yes; I succeeded in quieting an injector in one establishment where anything louder than the scratching of a goose-quill was considered a nuisance. I first began by putting a piece of paper against the mouth of the overflow pipe while the injector was working, and the noise ceased, but soon after that the paper was sucked up into the injector. I then applied a leathern disc, which answered well, and proved just the right thing; sometimes the water blurted out, but not often, and the leathern disc was permanently established; but the injector would not work with water above 100 degrees of heat; so I would start with cold water and gradually turn on the hot water and shut off the cold, and she never noticed the change, but the noise was stopped.

26. Question.—How would you quiet a noisy pump—one of those stuck up in a corner of the stoke-hold that can be heard, but not often seen?

Answer.—I had one of them once—a very good little "Manchester Donkey Pump," but as noisy as they make 'em—and it became a question whether she should be discarded for an injector; she was bolted to a wall in the basement of a block of offices and could be heard throughout the building, and my employer told me that he would willingly give a 5l. note to anyone who would stop the noise. The donkey was vertical; I took off both valve covers and drilled a ⅜-inch hole in each projection from the cover that gave the valve its lift, and drove a wooden peg into each hole from the under side, and rasped them down to give the required lift, and put the covers on again and started the donkey, and after some more raspings of the plugs I started her again, and this time was successful; she worked like india-rubber, no noise whatever, and I gained more than was offered to quiet her—a cheque of 21l. This happened in Draper's Gardens, Throgmorton Avenue, E.C.