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water line should also be carefully searched for. Fusible plugs, to be effective, must be kept clean, and the only opportunity for cleaning them is at the time of washing out the boiler. Therefore while working on the upper part of the boiler, attention should be given to the fusible plug. If it is one of the ordinary kind, screwed into the back head above the tubes, it should be taken out and cleaned and before replacing it the thread should be well coated with à mixture of cylinder oil and plumbago, which will prevent it from sticking. If the fusible plug is one of the type consisting of a brass tube extending from the top of the shell to the water level, the lower end of this tube should be cleaned of all mud or scale.

Having thus finished above the tubes, the mud and scale should again be scraped from the bottom, after which the hose should be inserted through the front man-hole that should be in every horizontal boiler.

Some authorities argue that a man-hole should not be cut in the bottom part of a boiler head, giving as their reason that it weakens the head, but the logic is not sound, for the reason that the man-hole can be reënforced in such a manner as to make it fully as strong as the solid sheet, and when we consider the great advantage of having a man-hole in the bottom, both as regards washing out and also for repairs, it is plain that it is really a necessity.

After washing out all the loose mud and scale that it is possible to get from the bottom, the boiler washer should next go inside and, with scrapers and tools made for the purpose, he should scrape and chip off all the scale that he can from the bottom, because there is where lies the greatest danger from burnt sheets caused by accumulations of scale preventing the

water from getting to the metal. Much good work may be accomplished in this way and no boiler washer should consider the job complete until he has gone through the boiler both top and bottom, and not only cleaned but inspected it. Any loose rivets, broken or loose braces, signs of corrosion or pitting should be at once reported to the' chief engineer or superintendent. It will thus be seen that great responsibility rests with the boiler washer, for the reason that he is the man that is in closest touch with the inside of the boiler, and it is due to the manner in which he does his work inside the boiler whether a defect is discovered and repaired in time or whether it is allowed to go until the result is often a grave disaster. The author desires to enter a plea for this hard-worked and too often underpaid craftsman, and hereby expresses the wish that his services were better appreciated.

The water column or combination should receive particular attention each time the boiler is washed out. The lower pipe leading to the boiler is liable to become clogged with scale, and if not cleaned regularly it is sure to cause trouble by preventing a free flow of the water from the boiler to the gauge glass.

If the boiler is of the horizontal tubular type, the tubes should be scraped inside, and with water tube boilers use the steam jet to blow the soot and ashes from between the tubes. Soot, in addition to choking the draft, is also a non-conductor of heat.

After the hand-hole and man-hole plates have been replaced the boiler may be filled with water to the proper level, and while this is being done it is in order to take a look into the furnace for any broken grates or accumulations of clinkers on the side walls or bridge wall. These clinkers should be chipped off, also the

bottom of the boiler should be swept clean of ashes and examined for any defects, such as fire cracks about the rivets most exposed to the heat. These cracks may often exist some time before being discovered unless a close inspection is made. They are small cracks radiating from the rivet holes outward past the rivet heads one-half to three-quarters of an inch, and are always liable to extend farther until they become a source of danger unless arrested in time. They may be closed up sometimes with the caulking tool, but if one should be found several inches in length, a hole should be drilled at the outer end of the crack and a rivet put in. This will generally stop it. Fire cracks occur in the girth seams only, and especially the seam nearest the fire.

It is essential that the bridge walls of horizontal boilers be kept in good repair, in order that as much fire brick surface as possible may be exposed to the heat. This will greatly aid combustion and prevent smoke.

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Firing Up. After the boiler washer has completed his task the next thing in order is firing up, and in doing this if care and good judgment are not exercised there is danger of doing much damage to the boiler, especially if it has been filled with cold water. very light fire should be started at first and kept that way until the water gets to the boiling point at least, after which the fire may be gradually increased until the steam gauge shows a few pounds pressure, when it will be safe to urge the fire still more. The bad effects resulting from the unequal expansion or contraction. of the sheets and undue stress upon the rivets, all caused by rapid changes of the temperature of the boiler from hot to cold or vice versa, cannot be

guarded against too carefully, and they are liable to be brought about in two ways: first, by haste in cooling down a hot boiler that is to be washed out, and secondly, by starting a heavy fire under a cold boiler. That part of the boiler most exposed to the heat will become hot while other parts farthest removed from the fire may still be cold. Very often there is a difference of 150° or 200° in the temperature of different parts of the boiler for a time during the firing up process, and the same dangerous conditions may be caused also by blowing all the water out of a boiler while under a pressure of 15 or 20 lbs., as is the custom of some persons when preparing a boiler for washing out. Either custom cannot be too strongly condemned.

Sometimes a boiler is needed in a hurry after having been washed out, and in such an emergency it should be filled with warm water; in fact, it is better to always fill a boiler with warm water if it is possible to do so after washing out.

Connecting with the Main Header. When the gauge shows a pressure that is within 10 or 15 lbs. of being the same as that carried on the other boilers it should be watched closely, and when the pressure becomes the same as that in the main the connecting valve should be opened slightly, just sufficient to allow a light flow of steam through it, which can be easily detected by placing the ear near the valve chamber. This steam may be passing from the boiler to the header or vice versa, but whichever way it is going the valve should not be opened any farther until the pressure in the main pipe and in the boiler is equalized, when it will be found that the valve may be opened easily. While connecting the boiler the dampers should be closed.

Care should always be exercised in connecting a recently fired up boiler, and the engineer should be certain that the steam gauge and pop valve are in good working order. Otherwise there is liability of a serious accident occurring, either in breakage of the steam pipe, or what is still worse, a boiler explosion

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