Part 8
_When you have_ your boiler furnace to repair, and cannot get fire clay, take common earth mixed with water, in which you have dissolved a little salt; use same as fire clay, and your furnace will last fully as long.
_To make iron take bright polish_ like steel, pulverize and dissolve the following articles in one quart of hot water: Blue vitriol 1 oz., borax 1 oz., prussiate of potash 1 oz., charcoal 1 oz., salt 7½ pt.; then add one gallon of linseed oil, mix well, bring your iron or steel to the proper heat, and cool in the solution.
_To write inscriptions on metal_, take 4 oz. of nitric acid and 1 oz. of muriatic acid, mix and shake well together, then cover your metal surface to be engraved, with bees-wax or soap, write your inscription plainly in the wax clear to the metal, then apply the mixed acids, carefully filling each letter. Let it remain from three to five minutes according to appearance desired, then throw on water, which stops the etching process, scrape off the bees-wax or soap, and the inscription is complete.
_To remove rust from steel._—Brush the rusted steel with a paste composed of ½ oz. cyanide potassium, ½ oz. castile soap, 1 oz. whiting, and enough water to make a paste; then wash the steel in a solution of ½ oz. cyanide potassium and 2 oz. of water.
_A solvent for rust._—It is often very difficult, and sometimes impossible, to remove rust from articles made of iron. Those which are most thickly coated are most easily cleaned by being immersed in, or saturated with, a solution of chloride of tin. The length of time they should remain in this bath is determined by the thickness of the rust, generally twelve to twenty-four hours is long enough. The solution ought not to contain a great excess of acid if the iron itself be not attacked. On taking them from the bath, the articles are rinsed first in water, then in ammonia, and quickly dried. The iron when thus treated has the appearance of dull silver; a simple polishing gives it its normal appearance.
_One of the best varnishes_ for smoke stacks or steam pipes is good asphaltum dissolved in oil of turpentine.
_Iron or steel immersed_ warm in a solution of carbonate of soda (washing soda) for a few minutes will not rust.
_Cement to fasten iron to stone._—Take 10 parts of fine iron filings, 30 parts of plaster of Paris, and ½ part of sal ammoniac; mix with weak vinegar to a fluid paste and apply at once.
_Cement for joints._—Paris white, ground, 4 lbs.; litharge, ground, 10 lbs.; yellow ochre, fine, ½ lb.; ½ oz. of hemp, cut short; mix well together with linseed oil to a stiff putty. This cement is good for joints on steam or water pipes; it will set under water.
_The average consumption of coal_ for steam boilers is 12 pounds per hour for each square foot of grate surface.
_One ton of coal_ is equivalent to two cords of wood for steam purposes.
_Doubling the diameter_ of a pipe increases its capacity four times.
_A cubic foot_ of water contains 7½ gallons.
_A gallon weighs_ 8⅓ pounds.
_Water expands_ ¹/₉ of its bulk in freezing.
_Ice weighs_ 56½ pounds per cubic foot.
_Engineers can judge_ of the condition of their machinery by the tone it gives out while running. Every make of engine has a peculiar tone of its own. The engineer becomes accustomed to that, and any departure from it at once excites a suspicion that all is not right. The engineer may not know what is the matter, he may have no ear for music, but the change in tone of his machine will be instantly perceptible and will start him upon an immediate investigation.
_An Indicator_ is an instrument used to determine the indicated horse-power of an engine; it shows the action of the steam in the cylinder and serves as a guide in setting valves to get the greatest amount of energy from the steam used.
_Atmospheric pressure_ is the weight of the air.
_To take lime from injector tubes_, mix one part muriatic acid and ten parts soft water. Immerse tube in this mixture over night.
_Compound for Cooling Heavy Bearings._—For cooling heavy pillow block bearings, or the steps of upright shafts, the following will be found very valuable: Four pounds of tallow, one-half pound of sugar of lead, three-fourths pound plumbago. When the tallow is melted (not boiling) add sugar of lead and let it dissolve; then put in the plumbago, and stir the whole mass until cold.
_A mixture_ of soft soap and black lead makes an excellent lubricant for gears, as it lessens the abrasion and noise and has the advantage over tallow of not becoming hard. It is also easily removed should it become necessary to clean the parts on which it has been used.
_The axles and axle arms_ of a traction engine should be well greased or oiled before moving, to prevent them from being cut and wearing both hub and axle rapidly.
WORKSHOP RECIPES.
LOAM.—Mixture of brick, clay and old foundry sand.
PARTING SAND.—Burnt sand scraped from the surface of castings.
BLACK WASH.—Charcoal, plumbago and size.
BLACKENING FOR MOLDS.—Charcoal powder, or in some instances fine coal dust.
MIXTURE FOR WELDING STEEL.—One part sal ammoniac, ten parts borax, pounded together and fused until clear. Then it is poured out and after cooling, reduce to powder.
RUST-JOINT CEMENT.—(Quickly setting.) One part sal ammoniac in powder (by weight), two parts flour of sulphur, eighty parts iron borings, made into a paste with water.
RUST JOINT.—(Slowly setting.) Two parts sal ammoniac, one part flour of sulphur, 200 parts iron borings. The latter cement is the best if the joint is not required for immediate use.
RED LEAD CEMENT FOR FACE JOINTS.—One part white lead, one part red lead, mixed with linseed oil to the proper consistency.
CASE HARDENING.—Place horn, hoof, bone dust, or shreds of leather, together with the article to be case hardened, in an iron box; subject to blood red heat, then immerse the article in cold water.
CASE HARDENING WITH PRUSSIATE OF POTASH.—Heat the article, after polishing, to a bright red; rub the surface over with prussiate of potash; allow it to cool to dull red, and immerse it in water.
CASE HARDENING MIXTURES.—Three parts of prussiate of potash, one part sal ammoniac; or, one part of prussiate of potash, two parts sal ammoniac and two parts bone dust.
GLUE TO RESIST MOISTURE.—One pound of glue, melted in two quarts of skim-milk.
MARINE GLUE.—One part of India rubber, twelve parts mineral naphtha or coal tar. Heat gently, mix, and add twenty parts of powdered shellac. Pour out on a slab to cool. Heat to about 250 degrees and it is ready for use.
GLUE CEMENT TO RESIST MOISTURE.—One part glue, one part black rosin, ¼ part red ochre, mixed with the least possible quantity of water; or, four parts of glue; or, one part oxide of iron, one part of boiled oil (by weight).
BABBITTING BOXES.
When the babbitt in a box is badly worn, and needs re-babbitting, remove the cap, take out the shaft and chip all the old babbitt out of both box and cap; then replace the shaft in the box, and line it up perfectly level and square by putting liners in between the shaft and the edges of the box; then put stiff putty around the shaft and against the box at both ends, to prevent the babbitt from running out; then heat the babbitt metal until it runs freely, and pour it into the box until it is full; then put on the cap, and place about the same amount of liners between its ends and the top of the shaft as was put under the shaft, with long liners of sheet iron or tin extending from one end to the other of the box, parallel with and on both sides of the shaft; then put putty around the shaft and against the cap at both ends; heat the metal again, and pour it in through the oil hole. After it is cool, remove the cap and liners, drill out the oil hole and replace the cap, being careful to put just enough liners under it so that the box will be tight and still have the shaft run cool.
COMPOUND ENGINES.
The Compound Engine dates from the year 1781, when Hornblower, a contemporary of Watt, conceived the idea of utilizing the force in the exhaust steam of the simple engine in a second cylinder.
From his crude design, the constant progress of experiment has developed the marvelous engines now used in ocean steamers, and in both large and small power plants, also on locomotives. Some of the compound engines built in the early part of the century show results, according to the records, not far behind the best attainable in modern times.
The era of the Compound locomotive engine began in Europe in 1876, but in this country half a dozen years would almost cover its history.
However, in this short time, its advantages in putting to profitable use the entire force of the steam supplied, has been so clearly shown, that it has evidently come to stay. Its availability as an efficient, economical, powerful high speed locomotive, demonstrates the value of the Compound as a farm traction engine, and makes it plain that it will be extremely serviceable on this class of engines.
The Compound Traction Engines belonging to the class known as the “Woolf,” or continuous expansion type, are so constructed that the steam passes directly from the high pressure to the low pressure cylinder without the intervention of any receiving chamber or steam chest. This arrangement is considered much better adapted to traction engine work, and to produce superior results under the varying conditions of this class of work than the “cross” compound, or what is generally styled the “receiver” type of compound engines, in which the high pressure cylinder exhausts into a receiver connected with the steam chest of the low pressure cylinder.
In the Woolf Compound as constructed, the cylinders are either cast in one piece, end to end, or cast separately and bolted together in substantially the same way, in order that perfect alignment can be secured by boring both cylinders at the same operation. This makes it not only easy to get them in line at the start, but it prevents any possibility of their getting out of line, which is a very important feature.
The pistons of both cylinders are upon the one rod, thus requiring only one cross-head, connecting rod and crank. There is but one steam chest, in which a valve is placed, with such relation to the valve seat which contain the ports leading to both cylinders, that it performs the double function of first admitting the steam to the high pressure cylinder, cutting off the admission at the proper time to allow expansion to take place there, and after high pressure piston has reached the end of its stroke, passing on the steam to the low pressure cylinder, where it is further expanded and exhausted in the usual manner after its work is done.
The valve is specially designed with cavities so arranged as to co-operate in increasing the area of opening to double the amount obtainable with an ordinary valve having the same travel.
Without some special provision, the full power of the compound engine cannot be exerted in starting, as the steam operates primarily on the high pressure piston only, which has led to the condemnation of the compound as a traction engine. This objection has been thoroughly overcome in the Woolf by means of a “converting valve,” rendering it possible to admit steam directly to the large or low pressure cylinder, thus largely increasing the power obtainable from the engine, even when exerting its maximum power as a compound. This arrangement can be used not only in starting, but also in cases of emergency, such as climbing steep hills, getting out of bad places on the road, or disposing of an especially tough cut in sawing, etc.
Without increasing the boiler pressure beyond that ordinarily used, the compound engine gets fully one-third more force out of the steam used than is at present obtainable with the simple engine as commonly worked.
In other words, the compound will show results compared favorably with a good condensing simple stationary engine doing the same work.
BALL TANDEM COMPOUND ENGINE.
The heavy case iron base is cast in two sections, the rear part being securely bolted to the front section. To the front section is also bolted the main engine frame. This frame contains the bar guides for the cross-head, and pillow block bearing for the double disc crank shaft, and also forms the front head for the low pressure cylinder, which is securely bolted to it.
The high pressure cylinder is attached to the low pressure cylinder by two brackets securely bolted, and is supported by a pedestal, bolted to the rear part of base. By this arrangement, both the high and low pressure pistons are upon the same piston rod, which necessitates of but one cross-head, connecting rod and crank.
The valve of the high pressure cylinder is operated and completely under the control of the automatic shaft governor attached to one of the band wheels, while the valve of the low pressure cylinder receives its motion from a single eccentric on crank shaft at opposite side of engine.
When engine is running, the steam enters the high pressure cylinder first, and after performing its work there, exhausts through the receiver pipe into the low pressure cylinder, and there exerts its minimum force by expansion, and passes out to the condenser, if used, or exhausts into the open air.
EXAMINATION OF ENGINEERS APPLYING FOR A LICENSE.
QUESTIONS WITH ANSWERS.
Q. How long have you run an engine?
Q. Have you done your own firing?
Q. What kinds of engines have you run?
Q. What would be your first duty if called upon to take charge of an engine?
A. To ascertain the exact condition of the boiler and all its attachments, such as safety valve, steam gauge, water gauge and cocks, pump, injector, blow-off valve, etc.; also the engine.
Q. How often would you blow off your boiler?
A. Once a week or month, according to the condition of feed water used.
Q. How many feet of heating surface is allowed per horse-power by builders of boilers?
A. From 12 to 15 square feet for flue and tubular boilers.
Q. How much steam pressure will be allowed on a boiler 40 inch diameter, ⅜ thick, 60,000 pounds T. S., ⅛ T. S. factor of safety?
A. One-sixth of tensile strength of plate multiplied by thickness of plate, divided by one-half of the diameter of boiler gives safe working pressure.
Q. How do you estimate the strength of a boiler?
A. By its diameter and thickness of material, single or double riveted.
Q. Which is the stronger, single or double riveted?
A. Double riveted is from 14 to 18 per cent. stronger than single.
Q. What is the use of a mud drum on a boiler?
A. To collect all the sediment from the water used in the boiler.
Q. What causes sediment to accumulate in boilers?
A. The use of impure or muddy water.
Q. How often should it be blown out?
A. Three or four times a day.
A. How much grate surface do boiler makers allow per horse-power?
A. About two-thirds of a square foot.
Q. What is the steam dome of a boiler used for?
A. For dry steam to collect in.
Q. Of what use is a safety valve on a boiler?
A. To prevent overpressure.
Q. What is your duty with reference to it?
A. Open it once or twice a day to see that it is in good order.
Q. Of what use is a check valve?
A. To prevent the water in boiler from returning into the pump or injector.
Q. What effect has cold water on hot boiler plates?
A. It will fracture them.
Q. How should the gauge cocks be located on a boiler?
A. So that the lowest gauge cock is about 1½ inches above the top row of flues.
Q. Where should the blow-off valve be located?
A. At the bottom of the fire box in locomotive style of boiler, or in the mud drum when used.
Q. How would you have check valve arranged?
A. With a stop cock between the boiler and check valve.
Q. Does a man-hole in the top shell of boiler weaken it?
A. Yes, to a certain extent.
Q. How many valves in a common plunger pump?
A. Two, a receiving and a discharge valve.
Q. How are they situated?
A. One at suction, the other at discharge end.
Q. How do you find the proper size of safety valve for boiler?
A. Two square feet of grate surface is allowed for one inch area of common lever valve, or three square feet of surface to one inch area of spring valve.
Q. Why do pumps fail to work at times?
A. Leak in the suction, leak around the plunger, leaky check valve, or valve out of order.
Q. Why do injectors fail to work at times?
A. Leak in suction, grit or dirt under seat of valve, or valve not seated properly.
Q. How often should a boiler be examined and tested?
A. Twice a year at least.
Q. How would you test a boiler?
A. By tapping it with a light hammer, and hydrostatic test, using warm water.
Q. Where does the feed water enter the boiler?
A. Below the water level, where the feed water will not strike the heated plates.
Q. What causes priming of boilers?
A. Too high water, not steam space enough, dirty feed water, misconstruction of boiler, or engine being too large for its capacity.
Q. How can you keep boilers clean or remove scale from them?
A. By regularly cleaning them thoroughly, and by the use of compounds.
Q. If you found a thin plate in your boiler what would you do?
A. Patch it on the inside, first cutting out the damaged part.
Q. Why cut out the damaged part of sheet, when putting on a patch?
A. To allow the water to rest against the patch to protect it from the intense heat.
Q. What would be the result if the damaged part of sheet was not cut out?
A. The water not coming in contact with the patch, it would soon bulge from the heat and crack.
Q. Why patch it on the inside?
A. Because the action that has weakened the plate before will act upon the patch, when this is worn it can be replaced.
Q. If you found you had to put on several patches what would you do?
A. Reduce the steam pressure.
Q. If you found a blister what would you do?
A. Cut it out and put a patch on the fire side.
Q. If you found a plate buckled or sagged what would you do?
A. Put a stay bolt through the center of the sag.
Q. What would you do with a cracked plate?
A. Cut out the damaged part and put a patch over it.
Q. How would you change the water in a boiler when steam is up?
A. By supplying more feed water and opening the surface blow-off at short intervals.
Q. When blowing off a boiler, would you leave the blow-off cock to attend to other work?
A. Never.
Q. What would you do to relieve the pressure on the boiler if the safety valve was stuck and steam constantly rising?
A. Cover the fire with coal or ashes, close draught door and open damper in smoke box; work off the steam with the engine and when boiler has cooled down put the safety valve in working order.
Q. What may be the result if you allow the water in the boiler to get low?
A. Burning of the crown sheet and flues and perhaps cause an explosion.
Q. Would you turn feed water into a boiler in which the water was very low?
A. Never, without first pulling the fire or covering it with dry ashes and allowing the steam to go down.
Q. If you allow water in the boiler to get too high what would be the result?
A. It would cause priming or foaming.
Q. Is priming or foaming dangerous to an engine?
A. Yes. It may cause breaking of cylinder head and wrecking of the engine.
Q. What are other causes for foaming or priming of a boiler?
A. Dirty and impure water.
A. W. STEVENS TRACTION ENGINE.
The position of the side crank engine upon the boiler allows of having the Rear Gear traction attachment.
The Engine frame, guides for cross-head, cylinder, steam chest, saddles, brackets and both pillow block bearings for crank shaft are cast in one piece and bolted to the boiler.
The frame is cast oval, and cross-head guides are of the locomotive style.
The Engine is furnished with a Friction Clutch, a specially designed Reversing Gear, Governor, Marsh steam pump, Injector; and is mounted upon an open bottom fire box locomotive boiler, with ash pan under fire box and dome at rear end.
The boiler is mounted upon the traction wheels by brackets bolted to the rear end, which contain the boxes for the main axle and cross shaft.
The traction wheels are of the cast iron rim type, with spokes cast in both rim and hub.
The steering wheel and band wheel are on opposite sides of boiler, and both engine and boiler are supplied with all necessary fittings.
Q. How would you stop foaming?
A. Close the throttle long enough to show the true level of water. If the level of the water is sufficiently high, feeding and blowing off will usually correct the difficulty.
Q. What would you do if you discovered the water gone from sight in the water glass?
A. Pull the fire or cover it over with dry ashes, and allow the boiler to cool off as quickly as possible; and would not open or close any of the steam outlets.
Q, What is a traction engine?
A. A traction engine is an engine the power of which is transmitted to the driving or ground wheels by a combination of gearing.
Q. What is an exhaust pipe?
A. The pipe through which the exhaust steam escapes from cylinder to smoke stack.
Q. What is the feed pipe?
A. The pipe through which the feed water passes from pump or injector to the boiler.
Q. What is the steam pipe?
A. The pipe through which steam is taken from the dome to the steam chest.
Q. What is a pet cock?
A. A small cock used in check valves, pipes and places where draining off water is necessary to prevent freezing.
Q. What is clearance in a steam cylinder?
A. It is the space between the cylinder head and piston head when the latter is at end of the stroke.
Q. What is “cushion” in a steam cylinder?
A. Cushion is the compression of steam let in through the lead of the valve in the clearance of the cylinder, and is for the purpose of catching the weight of the piston and rod, cross-head and connecting rod when the engine reaches the end of each stroke. It also keeps the engine from pounding.
Q. How much water would you blow off at any one time while running?
A. Never blow off more than one gauge.
Q. What are your general views regarding boiler explosions?
A. The greatest causes are from ignorance, carelessness and neglect.
Q. What precaution should you take if necessary to stop with a heavy fire in the furnace?
A. Close the draught door, and put the injector or pump at work.
Q. What is the proper height to carry water in the boiler?
A. About 2½ inches above top row of flues.
Q. At what pressure should you blow off a boiler?
A. At a pressure not to exceed ten pounds.
Q. If you wished to increase the power of an engine what would you do?
A. Increase its speed or get higher steam pressure.
Q. How do you find the horse-power of an engine?
A. Multiply the speed of piston travel in feet per minute by the total effective pressure upon the piston in pounds, and divide the product by 33,000.
Q. What is meant by “brass bound”?
A. Brass bound means that the half brasses touch each other and cannot be driven up any closer by the key.
Q. How would you remedy a brass bound box on crank-pin or wrist-pin?
A. Take off the boxes and file off the top and bottom edges, being careful not to take off too much.
Q. Does a perfect fitting or an imperfect fitting valve have the most friction?
A. An imperfect fitting one.
Q. How would you refit an imperfect fitting or leaky valve?
A. It should be re-faced on a planer or filed and scraped until it fits seat perfectly tight.
Q. How is a steam engine rated?
A. By amount of horse-power developed.
Q. What is a foot-pound?
A. One pound of force exerted through one foot of space.
Q. How many foot-pounds are required to lift 100 pounds one foot?
A. One hundred.
Q. How many foot-pounds required to lift one pound 100 feet?
A. One hundred.
Q. To lift 110 pounds through 300 feet how many foot-pounds required?