The Stoker's Catechism

by W. J. Connor

17. Question.—What is the most important appendage to a steam boiler?

Answer.—The safety-valve, but it is not always a safety-valve, when it is weighted to twice the amount the boiler is certified to be worked at safely. As an instance: Amongst the many engines employed at the Midland Extension Works, St. Pancras, was a light steam crane for hoisting earth from the deep excavations, there were in use small wooden skips, and the pressure of steam was forty-five lb.; but after a time there arrived large iron skips that the crane could not lift, even when empty; there were about twenty men depending on the crane for their work and the navvy-ganger was anxious for "something to be done," and the crane man hinted about weighting the safety-valve, and no sooner said than almost done; the safety spring balance was screwed down, and a railway chair suspended from it by strong copper wire, and the steam allowed to rise until it reached ninety lb. on the inch, and the big iron skips were hoisted with their load of heavy ballast as easily as the wooden ones had been. The boiler happened to stand it.

18. Question.—Have you any other instance?

Answer.—Yes; in an establishment in Hammersmith some years ago, the stoker was in the habit of putting a bit of iron on the end of the horizontal lever of a safety valve when the steam rose too high, and the manager was about, and when it went down he would take off the bit of iron and put it where he could find it for the next occasion. The manager had gone away one day, and advantage was taken of it to have a little carouse in which most of the men took a part; and when the steam rose the stoker popped his bit of iron on the lever and all was quiet for a time, when another noisy safety-valve began to blow off, and on went another bit of iron that stopped the noise, and during all this time the fires of seven or eight boilers were burning fiercely, and the stoker should have checked his fires instead of what he had done; but in the midst of the carouse all the boilers began to belch forth steam when the manager came on the scene. The stoker tried to pick off the bits of iron before the manager could see them, but the steam was to high for that; and when at last the noise subsided and the steam had cleared away, the whole of the revellers were on view, caught in a trap, as there was only one exit. Most of the men were fined or suspended, the bits of iron were discovered on the levers, and the stoker had a week's notice to clear out, and lock-up valves were fitted on every boiler and the keys kept in the manager's desk ever after.

19. Question.—Can you always depend on the safety-valve lifting when the steam rises?

Answer.—I always keep an eye on the pressure gauge, and if I find that the safety-valve does not lift at the pressure it ought to lift at I know that the valve is sticking, and I lift the lever and let the steam out; the cause of the sticking may be that the valve has worn down in its seat and becomes conical, or there may be a shoulder on the valve that would cause it to stick, or it may be that the lever and fulcrum were smeared with oily dirty waste in the process of cleaning and not wiped off, but left to bake between the parts, which would prevent the free action of the safety valve.

20. Question.—Why is the safety-valve lifted at times, especially when getting steam up?

Answer.—It is often done by old stokers as well as new ones, and is more of a silly habit than of trying the pressure of the steam, especially as there is nowadays a pressure gauge for every boiler in a stoke-hold. By lifting the safety-valve while steam is in the boiler and dropping it down again is a dangerous practice; there is a rush of steam to the valve when lifted, and when it drops the rush of steam is instantly stopped, and rebounds like an india-rubber ball hit against the wall, and this commotion within the boiler is likely to blow the stop-valve to pieces or the manhole cover off. Besides that, there is always dust floating on the surface of the water, especially in a boiler just cleaned, and when the valve is lifted the dust is carried up with the steam, and when the valve is dropped the dust is caught under it and often causes the valve to leak.

21. Question.—When the water in the gauge-glass appears motionless while the boiler is working, what does it portend, and how would you proceed to rectify the stagnation of the water?

Answer.—It portends that the passage for the water is choked and requires clearing, and I would lose no time in commencing to rectify the stoppage; as a stoker who is responsible for the safety of the boiler I am always prepared for emergencies. I commence by shutting both cocks of the glass, the steam and the water, and unscrew the small bolt in the water gauge, which is fixed there for the purpose of clearing the tube that conveys the water to the glass, and with an iron wire in one hand, I open the water cock with the other hand, and push the wire into the small hole from which I took the bolt, giving several pushes and pulls while the water and steam are flying out, until the tube is quite clear; then I withdraw the wire, shut the cock, and serve the steam cock in like manner; and while I was doing all this the bottom cock of the gauge (the blow-out cock) was open from the beginning. Then I commence to put the pressure on the glass by warming it with steam from the top cock slowly; then I open the water cock a little, and so on, alternately; then I commence shutting the blow-out cock a little. By these manœuvres the pressure on the glass is put on gradually instead of popping it on too suddenly and breaking the glass, as is often done by the more-haste-the-less-speed stoker; now I shut the bottom cock and open the other two, and the water bounds into the glass quite frisky, and the boiler is safe for the present.