TWO WAYS OF READING __________
Now there are two ways to read this book, and if I know just how you had read it I could tell you in a minute whether to take hold of an engine or leave it alone. If you have read it one way, you are most likely to say "it is no trick to run an engine." If you have read it the other way you will say, "It is no trouble to learn how to run an engine." Now this fellow will make an engineer, and will be a good one. He has read it carefully, noting the drift of my advice. Has discovered that the engineer is not expected to build an engine, or to improve it after it has been built. Has recognized the fact that the principle thing is to attend to his own business and let other people attend to theirs. That a monkey wrench is a tool to be left in the tool box till he knows he needs it. That muscle is a good thing to have but not necessary to the successful engineer. That an engineer with a bunch of waste in his hand is a better recommendation than an "engineer license." That good common sense, and a cool head is the very best tools he can have. Has learned that carelessness will get him into trouble, and that to "forget" costs money.
Now the fellow who said "It is no trick to run an engine," read this book another way. He did not see the little points. He was hunting for big theories, scientific theories, something he could not understand, and didn't find them. He expected to find some bright scheme to prevent a boiler from exploding, didn't notice the simple little statement, "keep water in it," that was too commonplace to notice. He was looking for cuts, diagrams, geometrical figures, theories for constructing engines and boilers and all that sort of thing and didn't find them. Hence "It is no trick to run an engine."
If this has been your idea of "Rough and Tumble Engineering" forget all about your theory, and go back and read it over and remember the little suggestions and don't expect this book to teach you how to build an engine. We didn't start out to teach you anything of the kind. That is a business of itself. A good engineer gets better money than the man who builds them. Read it as if you wanted to know how to run an engine and not how to build one.
Study the following questions and answers carefully. Don't learn them like you would a piece of poetry, but study them, see if they are practical; make yourself thoroughly acquainted with the rule for measuring the horse-power of an engine; make yourself so familiar with it that you could figure any engine without referring to the book. Don't stop at this, learn to figure the heating surface in any boiler. It will enable you to satisfy yourself whether you are working your boiler or engine too hard or what it ought to be capable of doing.
SOME THINGS TO KNOW
Q. What is fire? A. Fire is the rapid combustion or consuming of organic matter.
Q. What is water? A. Water is a compound of oxygen and hydrogen. In weight 88 9-I0 parts oxygen to II I-I0 hydrogen. It has its maximum density at 39 degrees Fahr., changes to steam at 2I2 degrees, and to ice at 32 degrees.
Q. What is smoke? A. It is unconsumed carbon finely divided escaping into open air.
Q. Is excessive smoke a waste of fuel?
A. Yes.
Q. How will you prevent it A. Keep a thin fire, and admit cold air sufficient to insure perfect combustion.
Q. What is low water as applied to a boiler? A. It is when the water is insufficient to cover all parts exposed to the flames.
Q. What is the first thing to do on discovering that you have
low water?
A. Pull out the fire.
Q. Would it be safe to open the safety valve at such time?
A. No.
Q. Why not? A. It would relieve the pressure on the water which being allowed to flow over the excessive hot iron would flash into steam, and might cause an explosion.
Q. Why do boilers sometimes explode just on the point of
starting the engine?
A. Because starting the engine has the same effect as
opening the safety valve.
Q. Are there any circumstances under which an engineer is justified in allowing the water to get low? A. No.
Q. Why do they sometimes do it?
A. From carelessness or ignorance.
Q. May not an engineer be deceived in the gauge of water?
A. Yes.
Q. Is he to be blamed under such circumstances?
A. Yes.
Q. Why? A. Because if he is deceived by it it shows he has neglected something.
Q. What is meant by "Priming." A. It is the passing of water in visible quantities into the cylinder with the steam.
Q. What would you consider the first duty of an engineer on discovering that the water was foaming or priming A. Open the cylinder cocks at once, and throttle the steam.
Q. Why would you do this? A. Open the cocks to enable the water to escape, and throttle the steam so that the water would settle.
Q. Is foaming the same as priming?
A. Yes and no.
Q. How do you make that out? A. A boiler may foam without priming, but it can't prime without first foaming..
Q. Where will you first discover that the water is foaming? A. It will appear in the glass gauge, the glass will have a milky appearance and the water will seem to be running down from the top, There will be a snapping or cracking in the cylinder as quick as priming begins.
Q. What causes a boiler to foam? A. There are a number of causes. It may come from faulty construction of boiler; it may have insufficient steam room. It may be, and usually is, from the use of bad water, muddy or stagnant water, or water containing any soapy substance.
Q. What would you do after being bothered in this way?
A. Clean out the-boiler and get better water if possible.
Q. How would you manage your pumps while the water was
foaming.
A. Keep them running full.
Q. Why? A. In order to make up for the extra amount of water going out with the steam.
Q. What is "cushion?" A. Cushion is steam retained or admitted in front of the piston head at the finish of stroke, or when the engine is on "center."
Q. What is it for? A. It helps to overcome the "inertia" and momentum of the reciprocating parts of the engine, and enables the engine to pass the center without a jar.
Q. How would you increase the cushion in an engine?
A. By increasing the lead.
Q. What is lead? A. It is the amount of opening the port shows on steam end of cylinder when the engine is on dead center.
Q. Is there any rule for giving an engine the proper lead?
A. No.
Q. Why not?
A. Owing to their variation in construction, speed, etc.
Q. What would you consider the proper amount of lead,
generally.
A. From I/32 to I/I6.
Q. What is "lap?" A. It is the distance the valve overlaps the steam ports when in mid position.
Q. What is lap for?
A. In order that the steam may be worked expansively.
Q. When does expansion occur in a cylinder? A. During the time between which the port closes and the point at which the exhaust opens.
Q. What would be the effect on an engine if the exhaust
opened too soon?
A. It would greatly lessen the power of the engine.
Q. What effect would too much lead have. A. It would also weaken the engine, as the steam would enter before the piston had reached the end of the stroke, and would tend to prevent it passing the center.
Q. What is the stroke of an engine?
A. It is the distance the piston travels in the cylinder.
Q. How do you find the speed of a piston per minute? A. Double the stroke and multiply it by the number of revolutions a minuet. Thus an engine with a 12 inch stroke would travel 24 inches, or 2 feet, at a revolution. If it made 200 revolutions a minute, the travel of piston would be 400 feet a minute.
Q. What is considered a horse power as applied to an
engine?
A. It is power sufficient to lift 33,000 pounds one foot high
in one minute.
Q. What is the indicated horse power of an engine? A. It is the actual work done by the steam in the cylinder as shown by an indicator.
Q. What is the actual horse power? A. It is the power actually given off by the driving belt and pulley.
Q. How would you find the horse power of an engine? A. Multiply the area of the piston by the average pressure, less 5; multiply this product by the number of feet the piston travels per minute; divide the product by 33,000; the result will be horse power of the engine.
Q. How will you find the area of piston?
A. Square the diameter of piston and multiply it by .7854.
Q. What do you mean by squaring the diameter? A. Multiplying it by itself. If a cylinder is 6 inches in diameter, 36 multiplied by .7854, gives the area in square inches.
Q. What do you mean by average pressure? A. If the pressure on boiler is 60 pounds, and the engine is cutting off at 1/2 stroke, the pressure for the full stroke would be 50 pounds.
Q. Why do you say less 5 pounds?
A. To allow for friction and condensation.
Q. What is the power of a 7 x 10 engine, running 200 revolutions, cutting off at 1/2 stroke with 60 pounds steam? A. 7 x 7 = 49 x .7854 = 38.4846. The average pressure of 60 pounds would be 50 pounds less 5 = 45 pounds; 38-4846 x 45 = 1731.8070 x .333 1/3, (the number of feet the piston travels per minute) 577,269.0000 by 33,000=17 1/2 horse power.
Q. What is a high pressure engine? A. It is an engine using steam at a high pressure and exhausting into the open air.
Q. What is a low pressure engine? A. It is one using steam at a low pressure and exhausting into a condenser, producing a vacuum, the piston being under steam pressure on one side and vacuum on the other.
Q. What class of engines are farm engines?
A. They are high pressure.
Q. Why?
A. They are less complicated and less expensive.
Q. What is the most economical pressure to carry on high
pressure engine?
A. From 90 to 110 pounds.
Q. Why is high pressure more economical than low pressure? A. Because the loss is greater in low pressure owing to the atmospheric pressure. With 45 pounds steam the pressure from the atmosphere is 15 pounds, or 1/3, leaving only 30 pounds of effective power; while with 90 pounds the atmospheric pressure is only 1-6 of the boiler pressure.
Q. Does it require any more fuel to carry I00 pounds than it does to carry 60 pounds? A. It don't require quite as much.
Q. If that is the case why not increase the pressure beyond this and save more fuel? A. Because we would soon pass the point of safety in a boiler, and the result would be the loss of life and property.
Q. What do you consider a safe working pressure on a boiler? A. That depends entirely on its diameter. While a boiler of 30 inches in diameter 3/8 inch iron would carry I40 pounds, a boiler of the same thickness 80 inches in diameter would have a safe working pressure of only 50 pounds, which shows that the safe working pressure decreases very rapidly as we increase the diameter of boiler. This is the safe working pressure for single riveted boilers of this diameter. To find the safe working pressure of a double riveted boiler of same diameter multiply the safe pressure of the single riveted by 70, and divide by 56, will give a safe pressure of a double riveted boiler.
Q. Why is a steel boiler superior to an iron boiler?
A. Because it is much lighter and stronger.
Q. Does boiler plate become stronger or weaker as it becomes heated? A. It becomes tougher or stronger as it is heated, till it reaches a temperature Of 550 degrees when it rapidly decreases its power of resistance as it is heated beyond this temperature.
Q. How do you account for this? A. Because after you pass the maximum temperature of 550 degrees, the more you raise the temperature the nearer you approach its fusing point when its tenacity or resisting power is nothing.
Q. What is the degree of heat necessary to fuse iron?
A. 2912 degrees.
Q. Steel?
A. 2532 degrees.
Q. What class of boilers are generally used in a threshing
engine?
A. The flue boiler and the tubular boiler.
Q. About what amount of heating and grate surface is required per horse power in a flue boiler. A. About 15 square feet of heating surface and 3/4 square feet of grate surface.
Q. What would you consider a fair evaporation in a flue
boiler?
A. Six pounds of water to I pound of coal.
Q. How do these dimensions compare in a tubular boiler. A. A tubular boiler will require I/4 less grate surface, and will evaporate about 8 pounds of water to I pound of coal.
Q. Which do you consider the most available?
A. The tubular boiler.
Q. Why?
A. It is more economical and is less liable to "collapse?"
Q. What do you mean by "collapse?"
A. It is a crushing in of a flue by external pressure.
Q. Is a tube of a large diameter more liable to collapse than one of small diameter? A. Yes.
Q. Why? A. Because its power of resistance is much less than a tube of small diameter.
Q. Is the pressure on the shell of a boiler the same as on the
tubes?
A. No.
Q. What is the difference? A. The shell of boiler has a tearing or internal pressure while the tubes have a crushing or external pressure.
Q. What causes an explosion? A. An explosion occurs generally from low water, allowing the iron to become overheated and thereby weakened and unable to withstand the pressure.
Q. What is a "burst?" A. It is that which occurs when through any defect the water and steam are allowed to escape freely without further injury to boiler.
Q. What is the best way to prevent an explosion or burst? A. (I) Never go beyond a safe working pressure. (2) Keep the boiler clean and in good repair. (3) Keep the safety valves in good shape and the water at its proper height.
Q. What is the first thing to do on going to your engine in
the morning?
A. See that the water is at its proper level.
Q. What is the proper level?
A. Up to the second gauge.
Q. When should you test or try the pop valve?
A. As soon as there is a sufficient pressure.
Q. How would you start your engine after it had been standing over night? A. Slowly.
Q. Why? A. In order to allow the cylinder to become hot, and that the water or condensed steam may escape without injury to the cylinder.
Q. What is the last thing to do at night? A. See that there is plenty of water in boiler, and if the weather is cold drain all pipes.
Q. What care should be taken of the fusable plug? A. Keep it scraped clean, and not allow it to become corroded on top.
Q. What is a fusible plug? A. It is a hollow cast plug screwed into the crown sheet or top of fire box, and having the hollow or center filled with lead or babbit.
Q. Is such a plug a protection to a boiler?
A. It is if kept in proper condition.
Q. Can you explain the principle of the fusible or soft plug as it is sometimes called? A. It is placed directly over the fire, and should the water fall below the crown sheet the lead fuses or melts and allows the steam to flow down on top of the fire, destroys the heat and prevents the burning of crown sheet.
Q. Why don't the lead fuse with water over it? A. Because the water absorbs the heat and prevents it reaching the fusing point.
Q. What is the fusing point of lead?
A. 618 degrees.
Q. Is there any objection to the soft plug?
A. There is, in the hands of some engineers.
Q. Why? A. It relieves him of the fear of a dry crown sheet, and gives him an apparent excuse for low water.
Q. Is this a real or legitimate objection?
A. It is not.
Q. What are the two distinct classes of boilers?
A. The externally and internally fired boilers.
Q. Which is the most economical?
A. The internally fired boiler.
Q. Why? A. Because the fuel is all consumed in close contact with the sides of furnace and the loss from radiation is less than in the externally fired.
Q. To what class does the farm or traction engine belong?
A. To the internally fired.
Q. How would you find the H.P. of such a boiler? A. Multiply in inches the circumference or square of furnace, by its length, then multiply, the circumference of one tube by its total length, and this product by the number of tubes also taking into account the surface in tube sheet, add these products together and divide by I44, this will give you the number of square feet of heating surface in boiler. Divide this by 14 or 15 which will give the H.P. of boiler.
Q. Why do you say 14 or 15? A. Because some claim that it requires 14 feet of heating surface to the H.P. and others 15. To give you my personal opinion I believe that any of the standard engines today with good coal and properly handled, will and are producing 1 H.P. for as low as every 10 feet of surface. But to be on the safe side it is well to divide by 15 to get the H.P. of your boiler, when good and bad fuel is considered.
Q. How would you find the approximate weight of a boiler by measurement? A. Find the number of square feet in surface of boiler and fire box, and as a sheet of boiler iron or steel 1/16 of an inch thick, and one foot square, weighs 2.52 pounds, would multiply the number of square feet by 2.52 and this product by the number of 16ths or thickness of boiler sheet, which would give the approximate, or very near the weight of the boiler.
Q. What would you recognize as points in a good engineer. A. A good engineer keeps his engine clean, washes the boiler whenever he thinks it needs it. Never meddles with his engine, and allows no one else to do so. Goes about his work quietly, and is always in his place, only talks when necessary, never hammers or bruises any part of his engine, allows no packing to become baked or burnt in the stuffing box or glands, renews them as quick as they show that they require it. Never neglects to oil, and then uses no more than is necessary. He carries a good gauge of water and a uniform pressure of steam. He allows no unusual noise about his engine to escape his notice he has taught his ear to be his guide. When a job is about finished you will see him cleaning his ash pan, getting his tools together, a good fire in fire box, in fact all ready to go, and he looses no time after the belt is thrown off. He hooks up to his load quietly, and is the first man ready to go.
*Q. When the piston head is in the exact center of cylinder, is the engine on the quarter? *A. It is supposed to be, but is not.
*Q. Why not?
A. The angularity of the rod prevents it reaching the quarter.
*Q. Then when the engine is on the exact quarter what position does the piston head occupy? A. It is nearest the end next to crank.
Q. If this is the case, which end of cylinder is supposed to be
the stronger?
A. The opposite end, or end furtherest from crank.
Q. Why? A. Because this end gets the benefit of the most travel, and as it makes it in the same time, it must travel faster.
*Q. At what part of the cylinder does the piston head reach
the greatest speed?
A. At and near the center.
*Q. Why? Figure this out for yourself. *Note. The above few questions are given for the purpose of getting you to notice the little peculiarities of the crank engine, and are not to be taken into consideration in the operation of the same.
Q. If you were on the road and should discover that you had low water, what would you do? A. I would drop my load and hunt a high place for the front end of my engine, and would do it quickly to.
Q. If by some accident the front end of your engine should drop down allowing the water to expose the crown sheet, what would you do? A. If I had a heavy and hot fire, would shovel dirt into the fire and smother it out.
Q. Why would you prefer this to drawing the fire? A. Because it would reduce the heat at once, instead of increasing it for a few minutes while drawing out the hot bed of coals, which is a very unpleasant job.
Q. Would you ever throw water in the fire box? A. No. It might crack the side sheets, and would most certainly start the flues.
Q. You say, in finding low water while on the road, you would run your engine with the front end on high ground. Why would you do this? A. In order that the water would raise over the crown sheet, and thus make it safe to pump up the water.
Q. While your engine was in this shape would you not expose the front end of flues'? A. Yes, but as the engine would not be working this would do no damage.
Q. If you were running in a hilly country how would you manage the boiler as regards water? A. Would carry as high as the engine would allow, without priming.
Q. Suppose you had a heavy load or about all you could handle, and should approach a long steep hill, what condition should the water and fire be to give you the most advantage? A. A moderately low gauge of water and a very hot fire.
Q. Why a moderately low gauge of water? A. Because the engine would not be so liable to draw the water or prime in making the hard pull.
Q. Why a very hot fire? A. So I could start the pumps full without impairing or cutting the pressure.
Q. When would you start your pump?
A. As soon as fairly started up the hill.
Q. Why? A. As most hills have two sides, I would start them full in order to have a safe gauge to go down, without stoping to pump up.
Q. What would a careful engineer do before starting to pull a load over a steep hill? A. He would examine his clutch, or gear pin.
Q. How would you proceed to figure the road speed of traction. A. Would first determine the circumference of driver, then ascertain how many revolutions the engine made to one of the drivers. Multiply the number of revolutions the engine makes per minute by 60, this will give the number of revolutions of engine per hour. Divide this by the number of revolutions the engine makes to the drivers once, and this will give you the number of revolutions the drivers will make in one hour, and multiplying this by the circumference of driver in feet, and it will tell you how many feet your engine is traveling per hour, and this divided by 5280, the number of feet in a mile, would tell you just what speed your engine would make on the road.
THINGS HANDY FOR THE ENGINEER ____________
The first edition of this work brought me a great many letters asking where certain articles could be procured, what I would recommend, etc. These questions required attention and as the writers had bought and paid for their book it was due them that they get the benefit of my experience, as nothing is so discouraging to the young engineer as to be continually annoyed by unreliable and inferior fittings used more or less on all engines. I have gone over my letter file and every article asked for will be taken up in the order, showing the relative importance of each article in the minds of engineers. For instance, more letters reached me asking for a good brand of oil than any other one article. Then comes injectors, lubricators have third place, and so on down the list. Now without any intention of advertising anybody's goods I will give you the benefit of my years of experience and will be very careful not to mention or recommend anything which is not strictly first class, at least so in my opinion, and as good as can be had in its class, yet in saying that these articles are good does not say that others are not equally as good. I am simply anticipating the numerous letters I otherwise would receive and am answering them in a lump bunch. If you have no occasion to procure any of these articles, the naming of them will do no harm, but should you want one or more you will make no mistake in any one of them.
OIL
As I have stated, more engineers asked for a good brand of oil than for any other one article and I will answer this with less satisfaction to myself than any other for this reason: You may know what you want, but you do not always get what you call for. Oil is one of those things that cannot be branded, the barrel can, but then it can be filled with the cheapest stuff on the market. If you can get Capital Cylinder Oil your valve will give you no trouble. If you call for this particular brand and it does not give you satisfaction don't blame me or the oil, go after the dealer; he did not give you what you called for. The same can be said of Renown Engine Oil. If you can always have this oil you will have no fault to find with its wearing qualities, and it will not gum on your engine, but as I have said, you may call for it and get something else. If your valve or cylinder is giving you any trouble and you have not perfect confidence in the dealer from whom you usually get your cylinder oil send direct to The Standard Oil Company for some Capital Cylinder Oil and you will get an oil that will go through your cylinder and come out the exhaust and still have some staying qualities to it. The trouble with so much of the so called cylinder oil is that it is so light that the moment it strikes the extreme heat in the steam chest it vaporizes and goes through the cylinder in the form of vapor and the valve and cylinder are getting no oil, although you are going through all the necessary means to oil them.
It is somewhat difficult to get a young engineer to understand why the cylinder requires one grade of oil and the engine another. This is only necessary as a matter of economy, cylinder or valve oil will do very well on the engine, but engine oil will not do for the cylinder. And as a less expensive oil will do for the engine we therefore use two grades of oil.
Engine oil however should be but little lower in quality than the cylinder oil, owing to the proximity of the bearings to the boiler, they are at all times more or less heated, and require a much heavier oil than a journal subject only to the heat of its own friction. The Renown Engine Oil has the peculiarity of body or lasting qualities combined with the fact that it does not gum on the hot iron and allows the engine to be wiped clean.