Rough and Tumble Engineering Part 1
Rough and Tumble Engineering.
by James H. Maggard.
PREFACE
In placing this book before the public the author wishes it understood that it is not his intention to produce a scientific work on engineering. Such a book would be valuable only to engineers of large stationary engines. In a nice engine room nice theories and scientific calculations are practical. This book is intended for engineers of farm and traction engines, "rough and tumble engineers," who have everything in their favor today, and tomorrow are in mud holes, who with the same engine do eight horse work one day and sixteen horse work the next day.
Reader, the author has had all these experiences and you will have them, but don't get discouraged. You can get through them to your entire satisfaction.
Don't conclude that all you are to do is to read this book. It will not make an engineer of you. But read it carefully, use good judgment and common sense, do as it tells you, and my word for it, in one month, you, for all practical purposes, will be a better engineer than four-fifths of the so-called engineers today, who think what they don't know would not make much of a book. Don't deceive yourself with the idea that what you get out of this will be merely "book learning." What is said in this will be plain, unvarnished, practical facts. It is not the author's intention to use any scientific terms, but plain, everyday field terms.
There will be a number of things you will not find in this book, but nothing will be left out that would be of practical value to you. You will not find any geometrical figures made up of circles, curves, angles, letters and figures in a vain effort to make you understand the principle of an eccentric. While it is all very nice to know these things, it is not necessary, and the putting of them in this book would defeat the very object for which it was intended. Be content with being a good, practical, everyday engineer, and all these things will come in time.
INTRODUCTORY
If you have not read the preface on the preceding pages, turn back and read it. You will see that we have stated there that we will use no scientific terms, but plain every day talk. It is presumed by us that there will be more young men, wishing to become good engineers, read this work than old engineers. We will, therefore, be all the more plain and say as little as possible that will tend to confuse the learner, and what we do say will be said in the same language that we would use if we were in the field, instructing you how to handle your engine. So if the more experienced engineer thinks we might have gone further in some certain points, he will please remember that by so doing we might confuse the less experienced, and thereby cover up the very point we tried to make. And yet it is not to be supposed that we will endeavor to make an engineer out of a man who never saw an engine. It is, therefore, not necessary to tell the learner how an engine is made or what it looks like. We are not trying to teach you how to build an engine, but rather how to handle one after it is built; how to know when it is in proper shape and how to let it alone when it is in shape. We will suppose that you already know as much as an ordinary water boy, and just here we will say that we have seen water haulers that were more capable of handling the engine for which they were hauling water, than the engineer, and the engineer would not have made a good water boy, for the reason that he was lazy, and we want the reader to stick a pin here, and if he has any symptoms of that complaint, don't undertake to run an engine, for a lazy engineer will spoil a good engine, if by no other means than getting it in the habit of loafing.
PART FIRST
In order to get the learner started, it is reasonable to suppose that the engine he is to run is in good running order. It would not be fair to put the green boy onto an old dilapidated, worn-out engine, for he might have to learn too fast, in order to get the engine running in good shape. He might have to learn so fast that he would get the big head, or have no head at all, by the time he got through with it. And I don't know but that a boy without a head is about as good as an engineer with the big head. We will, therefore, suppose that his engine is in good running order. By good running order we mean that it is all there, and in its proper place, and that with from ten to twenty pounds of steam, the engine will start off at a good lively pace. And let us say here, (remember that we are talking of the lone engine, no load considered,) that if you are starting a new engine and it starts off nice and easy with twenty pounds, you can make up your mind that you have an engine that is going to be nice to handle and give you but little, if any, trouble. But if it should require fifty or sixty pounds to start it, you want to keep your eyes open, something is tight; but don't take it to pieces. You might get more pieces than you would know what to do with. Oil the bearings freely and put your engine in motion and run it carefully for a while and see if you don't find something getting warm.
If you do, stop and loosen up a very little and start it up again. If it still heats, loosen about the same as before, and you will find that it will soon be all right. But remember to loosen but very little at a time, for a box or journal will heat from being too loose as quickly as from being too tight, and you will make trouble for yourself, for, inexperienced as you are, you don't know whether it is too loose or too tight, and if you have found a warm box, don't let that box take all of your attention, but keep an eye on all other bearings. Remember that we are not threshing yet, we just run the engine out of shed, (and for the sake of the engine and the young engineer, we hope that it did not stand out all winter) and are getting in shape for a good fall's run. In the meantime, to find out if anything heats, you can try your pumps, but to help you along, we will suppose that your pump, or injector, as the case may be, works all right.
Now suppose we go back where we started this new engine that was slow to start with less than fifty pounds, and when it did start, we watched it carefully and found after oiling thoroughly that nothing heated as far as we could see. So we conclude that the trouble must be in the cylinder. Well, what next? Must we take off the cylinder head and look for the trouble? Oh, no, not by any means. The trouble is not serious.
The rings are a little tight, which is no serious fault. Keep them well oiled and in a day or two ten pounds will start the empty engine in good shape. If you are starting an engine that has been run, the above instructions are not necessary, but if it is a new one these precautions are not out of the way, and a great deal of the trouble caused in starting a new engine, can be avoided if these precautions are observed.
It is not uncommon for a hot box to be caused from a coal cinder dropping in the box in shipment, and before starting a new engine, clean out the boxes thoroughly, which can be done by taking off the caps, or top box, and wiping the journal clean with an oily rag or waste, and every engineer should supply himself with this very necessary article, especially if he is the kind of an engineer who intends to keep his engine clean.
The engine should be run slowly and carefully for a while, to give a chance to find out if anything is going to heat, before putting on any load.
Now if your engine is all right, you can run the pressure up to the point of blowing off, which is from one hundred to one hundred and ten pounds. Most new pop valves, or safety valves, are set at this pressure. I would advise you to fire to this point, to see that your safety is all right. It is not uncommon for a new pop to stick, and as the steam runs up it is well to try it, by pulling the relief lever. If, on letting it go, it stops the escaping, steam at once, it is all right.
If, however, the steam continues to escape, the valve sticks in the chamber. Usually a slight tap with a wrench or a hammer will stop it at once, but never get excited over escaping steam, and perhaps here is as good a place as any to say to you, don't get excited over anything. As long as you have plenty of water, and know you have, there is no danger.
The young engineer will most likely wonder why we have not said something about the danger of explosions. We did not start to write about explosions. That is just what we don't want to have anything to do with. But, you say, is there no danger of a boiler exploding? Yes.
But if you wish to explode your boiler you must treat it very differently from the way we advise. We have just stated, that as long as you have plenty of water, and know you have, there is no danger.
Well, how are you to know? This is not a difficult thing to know, provided your boiler is fitted with the proper appliances, and all builders of any prominence, at this date, fit their boilers with from two to four try-c.o.c.ks, and a gla.s.s gauge. The boiler is tapped in from two to four places for the try-c.o.c.ks, the location of the c.o.c.ks ranging from a line on a level with the crown sheet, or top of fire box, to eight inches above, depending somewhat on the amount of water s.p.a.ce above the crown sheet, as this s.p.a.ce differs very materially in different makes of the same sized boiler. The boiler is also tapped on or near the level of crown sheet, to receive the lower water gla.s.s c.o.c.k and directly above this, for the top c.o.c.k. The s.p.a.ce between this shows the safe variation of the water. Don't let the water get above the top of the gla.s.s, for if you are running your engine at hard work, you may knock out a cylinder head, and don't let it get below the lower gauge, or you may get your head knocked off.
Now the gla.s.s gauge is put on for your convenience, as you can determine the location of the water as correctly by this as if you are looking directly into the boiler, provided, the gla.s.s gauge is in perfect order.
But as there are a number of ways in which it may become disarranged or unreliable, we want to impress on your mind that you, must not depend on it entirely. We will give these causes further on. You are not only provided with the gla.s.s gauge, but with the try-c.o.c.ks. These c.o.c.ks are located so that the upper and lower c.o.c.k is on or near the level with the lower and upper end of the gla.s.s gauge. With another try-c.o.c.k about on a level with the center of gla.s.s gauge, or in other words, if the water stands about the center of gla.s.s it will at the same time show at the c.o.c.k when tried. Now we will suppose that your gla.s.s gauge is in perfect condition and the water shows two inches in the gla.s.s. You now try the lower c.o.c.k, and find plenty of water; you will then try the next upper c.o.c.k and get steam. Now as the lower c.o.c.k is located below the water line, shown by the gla.s.s, and the second c.o.c.k above this line, you not only see the water line by the gla.s.s, but you have a way of proving it. Should the water be within two inches of the top of gla.s.s you again have the line between two c.o.c.ks and can also prove it. Now you can know for a certainty, where the water stands in the boiler, and we repeat when you know this, there is nothing to fear from this source, and as a properly constructed boiler never explodes, except from low water or high pressure, and as we have already cautioned you about your safety valve, you have nothing to fear, provided you have made up your mind to follow these instructions, and unless you can do this, let your job to one who can. Well, you say you will do as we have directed, we will then go back to the gauges. Don't depend on your gla.s.s gauge alone, for several reasons. One is, if you depend on the gla.s.s entirely, the try-c.o.c.ks become limed up and are useless, solely because they are not used.
Some time ago the writer was standing near a traction engine, when the engineer, (I guess I must call him that) asked me to stay with the engine a few minutes. I consented. After he had been gone a short time I thought I would look after the water. It showed about two inches in the gla.s.s, which was all right, but as I have advised you, I proposed to know that it was there and thought I would prove it by trying the c.o.c.ks.
But on attempting to try them I found them limed up solid. Had I been hunting an engineer, that fellow would not have secured the job.
Suppose that before I had looked at the gla.s.s, it had bursted, which it is liable to do any time. I would have shut the gauge c.o.c.ks off as soon as possible to stop the escaping steam and water. Then I would have tried the c.o.c.ks to find where the water was in the boiler. I would have been in a bad boat, not knowing whether I had water or not. Shortly after this the fellow that was helping the engine run (I guess I will put it that way) came back. I asked him what the trouble was with his try c.o.c.ks. He said, "Oh, I don't bother with them." I asked him what he would do if his gla.s.s should break. His reply was, "Oh, that won't break." Now just such an engineer as that spoils many a good engine, and then blames it on the manufacturer. Now this is one good reason why you are not to depend entirely on the gla.s.s gauge. Another equally as good reason is, that your gla.s.s may fool you, for you see the try-c.o.c.ks may lime up, so may your gla.s.s gauge c.o.c.ks, but you say you use them. You use them by looking at them. You are not letting the steam or water escape from them every few minutes and thereby cutting the lime away, as is the case with try-c.o.c.ks. Now you want to know how you are to keep them open. Well, that is easy. Shut off the top gauge and open the drain c.o.c.k at bottom of gauge c.o.c.k. This allows the water and steam to flow out of the lower c.o.c.k. Then after allowing it to escape a few seconds, shut off the lower gauge and open the top one, and allow it to blow about the same time. Then shut the drain c.o.c.k and open both gauge c.o.c.ks and you will see the water seek its level, and you can rest a.s.sured that it is reliable. This little operation I want you to perform every day you run an engine. It will prevent you from thinking you have water. I don't want you to think so. I intend that you shall know it. You remember we said, if you know you have water, you are safe, and every one around you will be safe.
Now here is something I want you to remember. Never be guilty of going to your engine in the morning and building a fire simply because you see water in the gla.s.s. We could give you the names of a score of men who have ruined their engines by doing this very thing. You, as a matter of course, want to know why this can do any harm. It could not, if the water in the boiler was as high as it shows in the gla.s.s, but it is not always there, and that is what causes the trouble. Well, if it showed in the gla.s.s, why was it not there? You probably have lived long enough in the world to know that there are a great many boys in it, and it seems to be second nature with them to turn everything on an engine that is possible to turn. All gla.s.s gauge c.o.c.ks are fitted with a small hand wheel. The small boy sees this about the first thing and he begins to turn it, and he generally turns as long as it turns easy, and when it stops he will try the other one, and when it stops he has done the mischief, by shutting the water off from the boiler, and all the water that was in the gla.s.s remains there. You may have stopped work with an ordinary gauge of water, and as water expands when heated, it also contracts when it becomes cool. Water will also simmer away, if there is any fire left in the fire box, especially if there should be any vent or leak in the boiler, and the water may by morning have dropped to as much as an inch below the crown sheet. You approach the engine and on looking at the gla.s.s, see two or three inches of water. Should you start a fire without investigating any further, you will have done the damage, while if you try the gauge c.o.c.ks first you will discover that some one has tampered with the engine. The boy did the mischief through no malicious motives, but we regret to say that there are people in this world who are mean enough to do this very thing, and not stop at what the boy did unconsciously, but after shutting the water in the gauge for the purpose of deceiving you, they then go to the blow-off c.o.c.k and let enough water out to insure a dry crown sheet. While I detest a human being guilty of such a dastardly trick, I have no sympathy to waste on an engineer who can be caught in this way. So, if by this time you have made up your mind never to build a fire until you know where the water is, you will never be fooled and will never have to explain an accident by saying, "I thought I had plenty of water." You may be fooled in another way. You are aware that when a boiler is fired up or in other words has a steam pressure on, the air is excluded, so when the boiler cools down, the steam condenses and becomes water again, hence the s.p.a.ce which was occupied by steam now when cold becomes a vacuum.
Now should your boiler be in perfect shape, we mean perfectly tight, your throttle equally as tight, your pump or injector in perfect condition and you were to' leave your engine with the hose in the tank, and the supply globe to your pump open, you will find on returning to your engine in the morning that the boiler will be nearly if not quite full of water. I have heard engineers say that someone had been tampering with their engines and storm around about it, while the facts were that the supply being open the water simply flowed in from atmospheric pressure, in order to fill the s.p.a.ce made vacant by the condensed steam. You will find further on that all check valves are arranged to prevent any flowing out from the boiler, but nothing to prevent water flowing in. Such an occurrence will do no harm but the knowing how it was done may prevent your giving yourself away. A good authority on steam boilers, says: "All explosions come either from poor material, poor workmanship, too high pressure, or a too low gauge of water." Now to protect yourself from the first two causes, buy your engine from some factory having a reputation for doing good work and for using good material. The last two causes depend very much on yourself, if you are running your own engine. If not, then see that you have an engineer who knows when his safety valve is in good shape and who knows when he has plenty of water, or knows enough to pull his fire, when for some reason, the water should become low. If poor material and poor workmanship were unknown and carelessness in engineers were unknown, such a thing as a boiler explosion would also be unknown.
You no doubt have made up your mind by this time that I have no use for a careless engineer, and let me add right here, that if you are inclined to be careless, forgetful,(they both mean about the same thing,) you are a mighty poor risk for an insurance company, but on the other hand if you are careful and attentive to business, you are as safe a risk as any one, and your success and the durability and life of your engine depends entirely upon you, and it is not worth your while to try to shift the responsibility of an accident to your engine upon some one else.
If you should go away from your engine and leave it with the water boy, or anyone who might be handy, or leave it alone, as is often done, and something goes wrong with the engine, you are at fault. You had no business to leave it, but you say you had to go to the separator and help fix something there. At the separator is not your place. It is not our intention to tell you how to run both ends of an outfit. We could not tell you if we wanted to. If the men at the separator can't handle it, get some one or get your boss to get some one who can. Your place is at the engine. If your engine is running nicely, there is all the more reason why you should stay by it, as that is the way to keep it running nicely. I have seen twenty dollars damage done to the separator and two days time lost all because the engineer was as near the separator as he was to the engine when a root went into the cylinder.
Stay with your engine, and if anything goes wrong at the separator, you are ready to stop and stop quickly, and if you are signalled to start you are ready to start at once You are therefore making time for your employer or for yourself and to make time while running a threshing outfit, means to make money. There are engineers running engines today who waste time enough every day to pay their wages.
There is one thing that may be a little difficult to learn, and that is to let your engine alone when it is all right. I once gave a young fellow a recommendation to a farmer who wanted an engineer, and afterward noticed that when I happened around he immediately picked up a wrench and commenced to loosen up first one thing and then another. If that engineer ever loses that recommendation he will be out of a job, if his getting one depends on my giving him another. I wish to say to the learner that that is not the way to run an engine. Whenever I happen to go around an engine, (and I never lose an opportunity) and see an engineer watching his engine, (now don't understand me to mean standing and gazing at it,) I conclude that he knows his business. What I mean by watching an engine is, every few minutes let your eye wander over the engine and you will be surprised to see how quickly you will detect anything out of place. So when I see an engineer watching his engine closely while running, I am most certain to see another commendable feature in a good engineer, and that is, when he stops his engine he will pick up a greasy rag and go over his engine carefully, wiping every working part, watching or looking carefully at every point that he touches. If a nut is working loose he finds it, if a bearing is hot he finds it. If any part of his engine has been cutting, he finds it. He picked up, a greasy rag instead of a wrench, for the engineer that understands his business and attends to it never picks up a wrench unless he has something to do with it. The good engineer took a greasy rag and while he was using it to clean his engine, he was at the same time carefully examining every part. His main object was to see that everything was all right. If he had found a nut loose or any part out of place, then he would have taken his wrench, for he had use for it.
Now what a contrast there is between this engineer and a poor one, and unfortunately there are hundreds of poor engineers running portable and traction engines. You will find a poor engineer very willing to talk.
This is bad habit number one. He cannot talk and have his mind on his work. Beginners must not forget this. When I tell you how to fire an engine you will understand how important it is, The poor engineer is very apt to ask an outsider to stay at his engine while he goes to the separator to talk. This is bad habit number two. Even if the outsider is a good engineer, he does not know whether the pump is throwing more water than is being used or whether it is throwing less. He can only ascertain this by watching the column of water in the gla.s.s, and he hardly knows whether to throw in fuel or not. He don't want the steam to go down and he don't know at what pressure the pop valve will blow off. There may be a box or journal that has been giving the engineer trouble and the outsider knows nothing about it. There are a dozen other good reasons why bad habit number two is very bad.
If you will watch the poor engineer when he stops his engine, he will, if he does anything, pick up a wrench, go around to the wrist pin, strike the key a little crack, draw a nut or peck away at something else, and can't see anything for grease and dirt. When he starts up, ten to one the wrist pin heats and he stops and loosens it up and then it knocks. Now if he had picked up a rag instead of a wrench, he would not have hit that key but he would have run his hand over it and if he had found it all right, he would have let it alone, and would have gone over the balance of the engine and when he started up again his engine would have looked better for the wiping it got and would have run just as well as before he stopped it. Now you will understand why a good engineer wears out more rags than wrenches, while a poor one wears out more wrenches than rags. Never bother an engine until it bothers you. If you do, you will make lots of grief for yourself.
I have mentioned the bad habits of a poor engineer so that you may avoid them. If you carefully avoid all the bad habits connected with the running of an engine, you will be certain to fall into good habits and will become a good engineer.
TINKERING ENGINEERS
After carelessness, meddling with an engine comes next in the list of bad habits. The tinkering engineer never knows whether his engine is in good shape or not, and the chances are that if he should get it in good shape he would not know enough to let it alone. If anything does actually get wrong with your engine, do not be afraid to take hold of it, for something must be done, and you are the one to do it, but before you do anything be certain that you know what is wrong. For instance, should the valve become disarranged on the valve stem or in any other way, do not try to remedy the trouble by changing the eccentric, or if the eccentric slips do not go to the valve to mend the trouble. I am well aware that among young engineers the impression prevails that a valve is a wonderful piece of mechanism liable to kick out of place and play smash generally. Now let me tell you right here that a valve (I mean the ordinary slide valve, such as is used on traction and portable engines), is one of the simplest parts of an engine, and you are not to lose any sleep about it, so be patient until I am ready to introduce you to this part of your work. You have a perfect right to know what is wrong with the engine. The trouble may not be so serious and it is evident to you that the engine is not running just as nicely as it should. Now, if your engine runs irregularly, that is if it runs up to a higher speed than you want, and then runs down, you are likely to say at once, "Oh I know what the trouble is, it is the governor." Well, suppose it is, what are you going to do about it, are you going to shut down at once and go to tinkering with it? No, don't do that, stay close to the throttle valve and watch the governor closely. Keep your eye on the governor stem, and when the engine starts off on one of its high speed tilts, you will see the stem go down through the stuffing box and then stop and stick in one place until the engine slows down below its regular speed, and it then lets loose and goes up quickly and your engine lopes off again. You have now located the trouble. It is in the stuffing box around the little bra.s.s rod or governor stem. The packing has become dry and by loosening it up and applying oil you may remedy the trouble until such time as you can repack it with fresh packing.
Candle wick is as good for this purpose as anything you can use.
But if the governor does not act as I have described and the stem seems to be perfectly free and easy in the box, and the governor still acts queerly, starting off and running fast for a few seconds, and then suddenly concluding to take it easy and away goes the engine again, see if the governor belt is all right, and if it is, it would be well for you to stop and see if a wheel is not loose. It might be either the little belt wheel or one of the little cog wheels. If you find these are all right, examine the spool on the crank shaft from which the governor is run and you will probably find it loose. If the engine has been run for any length of time, you will always find the trouble in one of these places, but if it is a new one the governor valve might fit a little tight in the valve chamber and you may have to take it out and use a little emery paper to take off the rough projections on the valve.
Never use a file on this valve if you can get emery paper, and I would advise you to always have some of it with you. It will often come handy. Now if the engine should start off at a lively gait and continue to run still faster, you must stop at once. The trouble this time is surely in the governor. If the belt is all right, examine the jam nuts on the top of the governor valve stem. You will probably find that these nuts have worked loose and the rod is working up, which will increase the speed of the engine. If these are all right, you will find that either a pulley or a little cog wheel is loose. A quick eye will locate the trouble before you have time to stop. If the belt is loose, the governor will lag while the engine will run away. If the wheel is loose, the governor will most likely stop and the engine will go on a tear. If the jam nut has worked loose, the governor will run as usual, except that it will increase its speed as the speed of the engine is increased. Now any of these little things may happen and are likely to.
None of them are serious, provided you take my advice, and remain near the engine. Now if you are thirty or forty feet away from the engine and the governor belt slips, or gets unlaced, or the pulley gets off, about the first thing the engine would do would be to jump out of the belt and by the time you get to it, it will be having a mighty lively time all alone. This might happen once and do no harm, and it might happen again and do a great deal of damage, and you are being paid to run the engine and you must stay by it. The governor is not a difficult thing to handle, but it requires your attention.
Now if I should drop the governor, you might say that I had not given you any instructions about how to regulate it to speed. I really do not know whether it is worth while to say much about it, for governors are of different designs and are necessarily differently arranged for regulating, but to help young learners I will take the Waters governors which I think the most generally used on threshing and farm engines.
You will find on the upper end of the valve or governor stem two little bra.s.s nuts. The upper one is a thumb nut and is made fast to the stem.
The second nut is a loose jam nut. To increase the speed of the engine loosen this jam nut and take hold of the thumb nut and turn it back slowly, watching the motion of your engine all the while. When you have obtained the speed you require, run the thumb nut down as tight as you can with your fingers. Never use a wrench on these nuts. To slow or slacken the speed, loosen the jam nut as before, except that you must run it up a few turns, then taking hold of the thumb nut, turn down slowly until you have the speed required, when you again set the thumb nut secure. In regulating the speed, be careful not to press down on the stem when turning, as this will make the engine run a little slower than it will after the pressure of your hand is removed.
If at any time your engine refuses to start with an open throttle, notice your governor stem, and you will find that it has been screwed down as far as it will go. This frequently happens with a new engine, the stem having been screwed down for its protection in transportation.
In traveling through timber with an engine, be very careful not to let any over-hanging limbs come in contact with the governor.
Now I think what I have said regarding this particular governor will enable you to handle any one you may come in contact with, as they are all very much alike in these respects. It is not my intention to take time and s.p.a.ce to describe a governor in detail. If you will follow the instructions I have given you the governor will attend to the rest.
PART SECOND __
WATER SUPPLY
If you want to be a successful engineer it is necessary to know all about the pump. I have no doubt that many who read this book, cannot tell why the old wooden pump (from which he has pumped water ever since he was tall enough to reach the handle) will pump water simply because he works the handle up and down. If you don't know this I have quite a task on my hands, for you must not attempt to run an engine until you know the principle of the pump. If you do understand the old town pump, I will not have much trouble with you, for while there is no old style wooden pump used on the engine, the same principles are used in the cross head pump. Do not imagine that a cross head pump means something to be dreaded. It is only a simple lift and force pump, driven from the cross head. That is where it gets its name and it don't mean that you are to get cross at it if it don't work, for nine times out of ten the fault will be yours. Now I am well aware that all engines do not have cross head pumps and with all respect to the builders of engines who do not use them, I am inclined to think that all standard farm engines ought to have a cross head pump, because it is the most simple and is the most economical, and if properly constructed, is the most reliable.
A cross head pump consists of a pump barrel, a plunger, one vertical check valve and two horizontal check valves, a globe valve and one stop c.o.c.k, with more or less piping. We will now locate each of these parts and will then note the part that each performs in the process of feeding the boiler.
You will find all, or most pump barrels, located under the cylinder of the engine. It is placed here for several reasons. It is out of the way. It is a convenient place from which to connect it to the cross head by which it is driven. On some engines it is located on the top or at the side of the cylinder and will work equally well. The plunger is connected with the cross head and in direct line with the pump barrel, and plays back and forth in the barrel. The vertical check valve is placed between the pump and the water supply. It is not absolutely necessary that the first check be a vertical one, but a check of some kind must be so placed. As the water is lifted up to the boiler it is more convenient to use a vertical check at this point. Just ahead and a few inches from the pump barrel is a horizontal check valve. Following the course of the water toward the point where it enters the boiler, you will find another check valve. This is called a "hot water check." just below this check, or between it and where the water enters the boiler, you will find a stop c.o.c.k or it may be a globe valve. They both answer the same purpose. I will tell you further on why a stop c.o.c.k is preferable to a globe valve. While the cross head pumps may differ as to location and arrangement, you will find that they all require the parts described and that the checks are so placed that they bear the same relation to each other. No fewer parts can be used in a pump required to lift water and force it against steam pressure. More check valves may be used, but it would not do to use less. Each has its work to do, and the failure of one defeats all the others. The pump barrel is a hollow cylinder, the chamber being large enough to admit the plunger which varies in size from 5/8 of an inch to I inch in diameter, depending upon the size of the boiler to be supplied. The barrel is usually a few inches longer than the stroke of the engine, and is provided at the cross head end with a stuffing box and nut. At the discharge end it is tapped out to admit of piping to conduct water from the pump. At the same end and at the extreme end of the travel of the plunger it is tapped for a second pipe through which the water from the supply reaches the pump barrel. The plunger is usually made of steel and turned down to fit snug in the chamber, and is long enough to play the full stroke of engine between the stuffing box and point of supply and to connect with the driver on the cross head. Now, we will take it for granted, that, to begin with, the pump is in good order, and we will start it up stroke at a time and watch its work. Now, if everything be in good order, we should have good water and a good hard rubber suction hose attached to the supply pipe just under the globe valve. When we start the pump we must open the little pet c.o.c.k between the two horizontal check valves. The globe valve must be open so as to let the water in. A check valve, whether it is vertical or horizontal, will allow water to pa.s.s through it one way only, if it is in good working order. If the water will pa.s.s through both ways, it is of no account.
Now, the engine starts on the outward stroke and draws the-plunger out of the chamber. This leaves a s.p.a.ce in the barrel which must be filled.
Air cannot get into it, because the pump is in perfect order, neither can the air get to it through the hose, as it is in the water, so that the pressure on the outside of the water causes it to flow up through the pipes through the first check valve and into the pump barrel, and fills the s.p.a.ce, and if the engine has a I2-inch stroke, and the plunger is I inch in diameter, we have a column of water in the pump I2 inches long and I inch in diameter.
The engine has now reached its outward stroke and starts back. The plunger comes back with it and takes the s.p.a.ce occupied by the water, which must get out of the way for the plunger. The water came up through the first check valve, but it can't get back that way as we have stated. There is another check valve just ahead, and as the plunger travels back it drives the water through this second check. When the plunger reaches the end of the backward stroke, it has driven the water all out. It then starts forward again, but the water which has been driven through the second check cannot get back and this s.p.a.ce must again be filled from supply, and the plunger continues to force more water through the second check, taking four or five strokes of the plunger to fill the pipes between the second check valve and the hot water check valve. If the gauge shows I00 pounds of steam, the hot water check is held shut by I00 pounds pressure, and when the s.p.a.ce between the check valves is filled with water, the next stroke of the plunger will force the water through the hot water check valve, which is held shut by the I00 pounds steam pressure so that the pump must force the water against this hot water check valve with a power greater than I00 pounds pressure. If the pump is in good condition, the plunger does its work and the water is forced through into the boiler.