Part 41 (1/2)
Before placing a new boiler in service, a careful and thorough exa The boiler as erected should correspond in its baffle openings, where baffles are adjustable, with the prints furnished for its erection, and such baffles should be tight The setting should be so constructed that the boiler is free to expand without interfering with the brickwork
This ability to expand applies also to blow-off and other piping After erection all mortar and chips of brick should be cleaned fro and then slacked slightly until the setting has beco The boiler should be exa to insure the absence of dirt, any foreign material such as waste, and tools Oil and paint are sometimes found in the interior of a new boiler and where such is the case, a quantity of soda ash should be placed within it, the boiler filled ater to its normal level and a slow fire started After twelve hours of slow si, the fire should be allowed to die out, the boiler cooled slowly and then opened and washed out thoroughly Such a proceeding will rerease fro and tube difficulties when the boiler is placed in service
The water colu should be examined and known to be free and clear The water level, as indicated by the gauge glass, should be checked by opening the gauge cocks
Thea boiler in operation is described later in the discussion of boiler settings
A boiler should not be cut into the line with other boilers until the pressure within it is approximately that in the steam main The boiler stop valve should be opened very slowly until it is fully opened The arrange should be such that there can be no possibility of water collecting in a pocket between the boiler and the main, from which it can be carried over into the steaular operation the safety valve and steae should be checked daily In small plants the steam pressure should be raised sufficiently to cause the safety valves to blow, at which tie should indicate the pressure at which the valve is known to be set If it does not, one is in error and the gauge should be compared with one of known accuracy and any error at once rectified
In large plants such a reat to be allowed Here the gauges and valves are ordinarily checked at the ti assured of not sticking by daily instantaneous opening throughof the safety valve acts not only as a check on the gauge but insures the valve against sticking
The water coluhly at least once on every shi+ft and the height of water indicated by the glass checked by the gauge cocks The bottoht These should be opened at least once daily to blow from the mud drum any sediment that may have collected and to reduce the concentration The a down and the frequency is, of course, determined by the nature of the feed water used
In case of loater, resulting either from carelessness or from some unforeseen condition of operation, the essential object to be obtained is the extinguishi+ng of the fire in the quickest possible manner Where practicable, this is best acco of a heavy stream of water from a hose on the fire Another enerally reco of the fire et ashes or fresh fuel A boiler so treated should be cut out of line after such an occurrence and a thorough inspection e, if any, has been done before it is again placed in service
The efficiency and capacity depend to an extent very reater than is ordinarily realized upon the cleanliness of the heating surfaces, both externally and internally, and too much stress cannot be put upon the necessity for systeular feature in the plant operation
The outer surfaces of the tubes should be blown free fro periods being dependent upon the class of fuel used Thesoot from the tubes is by means of a steam lance hich all parts of the surfaces are reached and swept clean There are nuned to be per Where such devices are installed, there are certain features that e of water of condensation within the setting co into contact with the boiler tubes, it will tend toward corrosion, or if in contact with the heated brickill cause rapid disintegration of the setting If the steaainst the tubes, erosion may take place Where such permanent soot blowers are installed, too ainst these possibilities
Internally, the tubes redients of which a study of the chapter on the i quantities in all feed waters Not only has the presence of scale a direct bearing on the efficiency and capacity to be obtained froainst the burning out of tubes
In the absence of a blow-pipe action of the flames, it is impossible to burn a metal surface where water is in intimate contact with that surface
In stoker-fired plants where a blast is used, and the furnace is not properly designed, there is a danger of a blow-pipe action if the fires are allowed to get too thin The rapid formation of stea of the metal of the tubes
Any formation of scale on the interior surface of a boiler keeps the water from such a surface and increases its tendency to burn Particles of loose scale that e at certain points in the tubes and localize this tendency at such points It is because of the danger of detaching scale and causing loose flakes to be present that the use of a boiler compound is not recommended for the removal of scale that has already formed in a boiler This question is covered in the treatment of feed waters If oil is allowed to enter a boiler, its action is the sa the water away fro 41]
It has been proven beyond a doubt that a very large percentage of tube losses is due directly to the presence of scale which, in many instances, has been so thin as to be considered of nosurfaces in a clean condition cannot be e can best be accomplished by means of an air or water-driven turbine, the cutter heads of which41 shows a turbine cleaner with various cutting heads, which has been found to give satisfactory service
Where a water-driven turbine is used, it should be connected to a puallons per minute per cleaner at 150 pounds pressure This pressure should never be less than 90 pounds if satisfactory results are desired Where an air-driven turbine is used, the pressure should be at least 100 pounds, though 150 pounds is preferable, and sufficient water should be introduced into the tube to keep the cutting head cool and assist in washi+ng down the scale as it is chipped off
Where scale has been allowed to accumulate to an excessive thickness, the work of removal is difficult and tedious Where such a heavy scale is of sulphate for the boiler ater to which there has been added a quantity of soda ash, a bucketful to each dru the water to boil for twenty-four hours with no pressure on the boiler It should be cooled slowly, drained, and the turbine cleaner used immediately, as the scale will tend to harden rapidly under the action of the air
Where oil has been allowed to get into a boiler, it should be re the boiler in service, as described previously where reference isout with soda ash
Where pitting or corrosion is noted, the parts affected should be carefully cleaned and the interior of the drums should be painted hite zinc if the boiler is to remain idle The cause of such action should be immediately ascertained and steps taken to apply the proper re an internal inspection of a boiler or when cleaning the interior heating surfaces, great care ainst the possibility of stea the boiler in question froh the careless opening of the boiler stop valve or some auxiliary valve or fro have resulted frolect of this precaution
Boiler brickwork should be kept pointed up and all cracks filled The boiler baffles should be kept tight to prevent by-passing of any gases through the heating surfaces
Boilers should be taken out of service at regular intervals for cleaning and repairs When this is done, the boiler should be cooled slowly, and when possible, be allowed to stand for twenty-four hours after the fire is drawn before opening The cooling process should not be hurried by allowing cold air to rush through the setting as this will invariably cause trouble with the brickwork When a boiler is off for cleaning, a careful examination should be made of its condition, both external and internal, and all leaks of stea stopped If water is allowed to coration will take place If water is allowed to come into contact with the metal of the boiler when out of service, there is a likelihood of corrosion