INTRODUCTION

NOWADAYS there are so many very interesting things going on all about us that very often we are likely to overlook things which have an important bearing on our everyday life. Small things which we are so used to having around that we never stop to think what they really mean to us.

For instance water. It's nice to drink, and bathe in but very few of us ever stop to consider the innumerable uses water is put to and what a great influence it has on many things we do. Most of us are satisfied to turn on the faucet and get our water in that way. If something is wrong and the water doesn't come from the faucet we call up the plumber, but we do not realize what has gone wrong simply because we do not understand how a house is piped for water nor do we understand why water gets into the pipes, etc.

Then air - another thing which we couldn't live without and yet few appreciate its value. Air and water give us tremendous results as pneumatic and hydraulic pressure. A knowledge of these great forces which most boys are so familiar with and still do not understand thoroughly will put you up far ahead of your boy friends. Most boys take things too much for granted; it is the clever boy Who digs into things and find out the reasons.

It is the earnest hope of the authors of this book that the boys who read it will have a better understanding of water and air, how they are used, and what they mean to us.

Sincerely yours,

COPYRIGHTED, 1920, BY A. C. GlLBERT
NEW HAVEN, CONN.

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City Water Supply Figs. 1, 2 Pages 5, 6
Private Water Supply Figs. 3, 4 Pages 7, 8
Attic Tank System Figs. 7, 8 Page 10
Water Supply From Spring Figs. 11, 12 Page 12
Pneumatic Tank Figs. 22, 23 Page 16
Siphon Over Hill Figs. 31, 33, 35 Pages 21, 22
Lift Pump Figs. 62, 63 Page 43
Force Pump Fig. 65 Page 45
Hydraulic Press Figs. 68A, 73 Pages 48, 52
Hydraulic Elevator Figs. 68B, 75 Pages 48, 53
Hydraulic Lift Lock Figs. 68C, 79, 81, 82 Pages 48, 55, 58
Depth Bomb Fig. 90 Page 66
Torpedo Figs. 91, 92 Page 67
Submarine Fig. 93 Page 68
Battleship Fig. 98 Page 72
Raising Sunken Ships Figs. 105, 106, 108 Pages 79, 80, 81
Floating Dry Docks Figs. 109, 110 Pages 82, 83
Air Lock in Pipes Figs. 120, 121 Pages 90, 91

Magdeburg Hemispheres Fig. 122 Page 93
Barometer Figs. 129, 130 Page 99
Air Zones Fig. 131 Page 100
Altitude Gauge Fig. 132 Page 101
Air Lift Pump Figs. 139, 140 Pages 105, 106
Balloons Figs. 144, 145 Pages 110, 111
Helium Balloons Fig. 146 Page 112
Air Brakes Figs. 156, 157 Pages 121, 122
Flame Thrower Fig. 158 Page 123
Fire Extinguisher Fig. 160 Page 124
Bicycle Pumps Fig. 165 Page 128
Air Compressor Fig. 167 Page 130
Sand Blast Fig. 168 Page 130
Pneumatic Paint Brush Fig. 170 Page 132
Diving Bell Figs. 172, 173 Pages 133, 134
Pneumatic Caisson Figs. 176, 177 Page 137
Torpedo Discharge Tube Fig. 178 Page 138
Air From Sea Water Fig. 180 Page 140

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CHART OF HYDRAULIC AND PNEUMATIC SEPARATE PARTS

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Hydraulic and Pneumatic Engineering

Hydraulic Engineering is the Engineering which deals with water and other liquids.

Pneumatic Engineering is the Engineering which deals with air and other gases.

Boys, have you running water in your homes? If so, do you know how it gets there? You will show how with this Engineering set.

If you live in a city, your running water is supplied in one of three ways: first, it is pumped into a standpipe or reservoir; second, it is brought from a distant lake or stream at a higher level; or third, it is pumped directly into the city mains.

The standpipe method is illustrated in Fig. 1. The water is pumped by means of a force pump B from a river or lake A into a standpipe C, from which it runs by gravity through the under-ground pipes or mains to the houses D, fountains E and hydrants F. This system is used in towns and small cities situated in a flat region, because it is the cheapest means of getting the water above the level of the highest house faucet in the town.

If the town is situated near a hill, the usual practice is to build a large cement lined reservoir on the hill and to pump the water into this instead of into a standpipe. In either case the water runs by gravity through the mains and submains to the houses, hydrants, etc.

If the city is very large, the usual practice is to bring the water from a lake or stream at a higher level. New York is supplied with water in this way.

See page 145 for diagram of apparatus needed to perform experiments in this book.

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6  HYDRAULIC AND PNEUMATIC ENGINEERING

If the city is very large and if an elevated lake or stream cannot be found within a reasonable distance, the usual practice is to pump the water directly into the city mains, from the nearest river or lake.

In all cases the greatest care is taken to see that the water is pure. The land bordering the elevated lake or stream is kept free from all sources of contamination and in addition the water is filtered. If the water is pumped from a lake, the intake pipe is run out into the lake for a long distance, to get the purest water and in addition the water is filtered. If the water is pumped from a river near the city, it is taken in above the city and is filtered.

EXPERIMENT No. 1

To make and operate a city water supply system in which the water comes from a standpipe, reservoir or lake.

Arrange the apparatus as shown in Fig. 2 and bury the mains an inch or two in sand or earth if convenient. Allow the water to run from the house faucet, that is, the nozzle. Attach an elbow, hose, and nozzle to the hydrant, that is, the coupling, and allow the water to run.

You have here shown how the water runs from a standpipe, reservoir, or elevated lake, through the mains to the hydrants in the streets of a city and to the faucets in the houses.

NOTE 1. When you wish to insert a glass tube into a rubber stopper or coupling always place the stopper or coupling in a glass of water to wet the rubber on the inside, then insert the glass tubes with a twisting motion. Always hold the glass tube near the end you are inserting into the rubber stopper or coupling. Thi is very important, because, if you hold the tube too far back, you may break it.

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HYDRAULIC AND PNEUMATIC ENGINEERING 7

NOTE 2. When you are through with an experiment always take the apparatus apart. Be sure particularly not to leave a glass tube in a rubber coupling or stopper because the tube will stretch the rubber permanently and the glass and rubber will stick together.

NOTE 3. Make the experiments out of doors, in the garage, in the basement, or in the bathroom. Keep all unused tubes in the box where you will not step on them.

NOTE 4. Let Dad enjoy this with you; he was a boy once, and will enjoy the fun as much as you do.

If you live in the country, or in a town where there is no public water supply system, and if you have running water in your home, you must have a private water supply system of some kind.

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8 HYDRAULIC AND PNEUMATIC ENGINEERING

In the system shown in Fig. 3 the water is pumped by means of a windmill and force pump into a tank on a tower and from this it runs by gravity to the house, the fountain, and the stable. The drawing in Fig. 4 shows how the water from the tank is distributed to the laundry, kitchen, and bathroom of the house.

To make and operate a private water supply system in which the water is stored in a tank on a tower.

Arrange the apparatus as in Fig. 5. Hold the nozzles horizontal and open them one at a time, then together. Is the stream from the lower nozzle longer than that from the upper?

Arrange the apparatus as shown in Fig. 6. Open the nozzles when horizontal and at the same level Are the streams of equal lengths?

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HYDRAULIC AND PNEUMATIC ENGINEERING  9

You have shown here how the water runs from a tank on a tower through the vertical pipe and underground pipe to the faucets in the house. You have shown also that the pressure is greater at a lower faucet than at an upper faucet and that the pressures are equal at faucets on the same level.

In Fig. 7 the water is pumped by a wind-mill and force pump into a tank in the attic of the house, and from there it runs by gravity to the various house fixtures as shown in Fig. 8. The force pump is often driven by a gas engine instead of by a windmill. The hand pump (4) Fig. 8 is used only when the gas engine or windmill is out of order.

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To make and operate a private water supply system in which the water is stored in an attic tank.

Arrange the apparatus as in Fig. 9. Hold the nozzles horizontal one above the other and open them together. Is the longer stream from the lower nozzle? That is, is the greater pressure at the lower faucet?

Arrange the apparatus as in Fig. 10. Hold the nozzles horizontal and open them together. Are the streams of the same length? That is, are the pressures equal?

You have shown here again that the greater pressure is at the lower faucet and that the pressures are equal at faucets on the same level.

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12 HYDRAULIC AND PNEUMATIC ENGINEERING

 

In Fig. 11 the water from an elevated spring runs by gravity into a storage tank and then through an underground pipe to the house fixtures.

To show how water is brought from an elevated lake or spring. 

Arrange the apparatus as shown in Fig. 12. Place the tank on a mound of sand or earth and bury the underground pipe to a depth of one or two inches. Allow the water to run.

You have shown here how the water is brought to a city from an elevated lake or stream, or how it is brought to a private house from an elevated spring.

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HYDRAULIC AND PNEUMATIC ENGINEERING 13

A NAVAL BATTLE
GAME No. 1

You can invent all sorts of games to be played with this Engineering set. The Naval Battle is one and it is an excellent game for a hot day.
Float a number of tin cans, tumblers, or cups on water in a bath tub, or in a wash tub, Fig. 13. Arrange the apparatus as shown. Each player directs his stream against the warships of the other, and the winner is the one who first sinks all the enemy war ships.

PNEUMATIC TANK SYSTEM OF WATER SUPPLY

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14 HYDRAULIC AND PNEUMATIC ENGINEERING

To make and operate a pneumatic tank.

Arrange the apparatus as shown in Fig. 16. It is necessary to fasten the stopper in the bottle very securely. Do this as follows: Insert two elbows into the two-hole rubber stopper and twist the stopper firmly into the neck of the bottle. Next loop three strong rubber bands together as shown in Fig. 17, pass a stout cord over the stopper and wind the stretched rubber bands around the neck and cord. Now slip the last end of the bands under the last winding to hold it, (1) Fig. 18, then tie the ends of the cord up over the stopper, (2) Fig. 18, and you will find that the stopper is very secure.


The stretched rubber bands make a very secure tie because each Stretched winding grips the cord. You will use this tie often in your experiments.


Note - You can use the tee and one-hole stopper instead of the elbows and two-hole stopper if you prefer.

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HYDRAULIC AND PNEUMATIC ENGINEERING 15

Now: open the clip on the hose, open the faucet Fig. 16, slightly, run water into the bottle until it is half full, close the faucet, close the clip on the hose, remove stopper from faucet, point the nozzle upward, and open the clip on the nozzle.

Does the compressed air force the water out with surprising force? If you have no water faucet handy, illustrate the pneumatic tank as shown in Fig. 19. Fill the bottle half full of water, tie the stopper in place, force air in with your mouth or with a bicycle pump, and observe the stream as before.


Find a larger bottle, which your stoppers will fit, and repeat these experiments.

You have shown here how the compressed air in a pneumatic tank forces the water out through the discharge pipe. Repeat and make experiments of your own.

Note - Do not attempt to fill the bottle more than half full of water because the air pressure increases rapidly as the air is compressed and it blows out the nozzle or separates the rubber tubes from the elbows.

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16 HYDRAULIC AND PNEUMATIC ENGINEERING

Arrange the bottle as shown in Fig. 21 and fill it half full of water. Replace the elbow by a nozzle as in Fig. 20 and your rapid fire water gun is complete. Open the clip for an instant only for each shot.

Arrange a battle with one or more on a side, each soldier armed with a rapid fire water gun. A man is wounded when hit on the arm or leg and must afterwards fight without the arm or leg; a man is killed when hit on the body or head. The side loses which first has all of its men killed. Use forts, trenches, tanks, etc.

To make and operate a pneumatic tank system of water supply.

Arrange the apparatus as in Fig. 22, fill the bottle half full of water as above, open the clip on the discharge tube, and observe the height to which the compressed air lifts the water.

Repeat with the apparatus as in Fig. 23. Do you observe that the stream from the lower nozzle is longer than that from the upper; that is, that in the pneumatic system also the pressure is always greater at the lower faucet?

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HYDRAULIC AND PNEUMATIC ENGINEERING 17

Repeat with the apparatus as in Fig. 24. Do you observe that the streams are of the same lengths, that is, that the pressures are equal at faucets on the same level?

You have shown here how the compressed air in a pneumatic tank forces water up to the faucets above; also that the greater pressure is at the lower faucet, and that the pressures are equal at faucets on the same level.

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18 HYDRAULIC AND PNEUMATIC ENGINEERING

WATER AND AIR

To show that water is incompressible and that air is compressible.

Arrange the apparatus as in Fig. 25, fill the tube with water and try to compress it. You cannot do so because water is nearly incompressible.

Note: Water as slightly compressed by very great pressures; for example, if your tube were 10 in. long and you could apply a pressure of 3000 lbs. per square inch, the water would be compressed 1/10 inch.

Now empty out the water and try to compress the air in the tube as in (2) Fig. 25. You will find that you can do so quite easily because air is quite compressible.

You have demonstrated here that water is incompressible (nearly) and that air is compressible. You know from this that in the pneumatic tank it is the air which is compressed and not the water. 

To show that compressed air exerts pressure.

Use the apparatus shown in Fig. 26. Wet the inside of the tube, wet the plunger and rub it on a cake of soap to make it slippery, shove the plunger into the tube (1) and let it go suddenly.

Do you find that the compressed air drives the plunger out violently (2)?

Repeat with a little water above the plunger to serve as a lubricant.

Note: When you shove the handle into the stopper you expand the stopper slightly. You should expand it until it fits the tube snugly but not too tightly. 

Hold the apparatus as in (3), Fig. 26 and force the handle in until the compressed air drives out the end stopper.

You have shown here that compressed air exerts pressure and you will understand from this how the compressed air drives the water out of a pneumatic tank;

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HYDRAULIC AND PNEUMATIC ENGINEERING 19

also you will understand why the tank must be made of steel, namely, to stand the pressure of the compressed air.

You can imitate the Stokes trench gun as follows. Put two long strips of paper on the ground three feet apart to represent the enemy trench. Now go back 20 or 30 feet or more, point the tube upward and toward the enemy trench, force the plunger in and release it suddenly. The game is to try to drop the bomb, that is, the plunger, into the enemy trench. The winner is the one who does it most often in a given number of trials.

Note: Keep the inside of the tube wet, the plunger wet and slippery with soap, and a little water above the plunger.

Use the apparatus as above. The game is to see who can shoot the plunger to the greatest height and to the greatest distance.

Use the apparatus as a pop gun, Fig. 28. The games are: first, to try to hit a bull's eye, with the end stopper; second, to see which can shoot it to the greatest distance and the greatest height.

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20 HYDRAULIC AND PNEUMATIC ENGINEERING

The siphon is used in many water supply systems to make water flow over the top of a storage tank or over a hill from a spring on one side to a house on the other, and so on.

You will first show how the siphon works, then you will show how it is used in water supply system, and later you will show why it works as it does.

EXPERIMENT No. 9
To make and operate a siphon.

Arrange the apparatus as in (1), Fig. 30. Place one arm of the siphon in the water and while holding the other arm outside the tank below the water level suck the air out of the siphon until the water runs.

Does the water run up hill to the top of the siphon and then down hill into the tumbler?

Siphon water out of a full tumbler into an empty tumbler and while the water is running stand them side by side on the table, (2), Fig. 30.

Does the water stop when the level is the same in both tumblers?

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HYDRAULIC AND PNEUMATIC ENGINEERING 21

Place one tumbler on a block of wood or a book as in (3), Fig. 30.

Does the water flow from the upper tumbler to the lower, and does the flow again stop when the levels are the same?

Place the block under the other tumbler.

Are the results the same?

Repeat the above experiments with the rubber hose, (4), Fig. 30, used as a siphon.

You have shown here: that the water runs uphill in one arm of a siphon and downhill in the other; that it always runs from the higher
water level to the lower; and that it stops running when the water levels are the same.

You will show "why" the water runs, in later experiments.

EXPERIMENT No. 10
To show how the siphon is used in water supply systems.

It is rather difficult to make a water-tight connection in the bottom of a water tank and in many cases it is not done, but instead the water is siphoned out over the top, as shown in Fig. 31.

Illustrate this as shown in Fig, 32.

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22 HYDRAULIC AND PNEUMATIC ENGINEERING

In some cases it happens that there is a good spring of water on one side of a hill and the home in which the water is wanted is on the other side. If the highest point  of the siphon is not more than about 25 feet (34 feet is the theoretical limit) above the water surface in the spring, and if the house faucets are below the level of the water in the spring, the water can be siphoned over the hill as shown in Fig. 33.


Illustrate this as shown in Fig. 34, where the back of the chair represents the hill.

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HYDRAULIC AND PNEUMATIC ENGINEERING 23

Water can be siphoned from a storage tank or reservoir over a hill as well as from a spring and the siphon can start at the bottom of the reservoir if this is more convenient, see Fig. 35.


Illustrate this as shown in Fig. 36.

You have here illustrated three ways in which the siphon is used in water supply systems. You will show later why a siphon cannot lift water over a rise of more than about 25 feet and why the greatest theoretical lift is 34 feet.

HOW TO START A LARGE SIPHON

EXPERIMENT No. 11
To illustrate different ways of siphon.

You could not start a large siphon by sucking the air out of it with your mouth. How then are you going to start it? You will illustrate three ways. The object in all cases is to get the air out of the siphon and this is usually done by filling it with water.

In the case illustrated in Fig. 37, the faucets are all closed and the air is driven out of the siphon by pumping water into the tank through the siphon. The check valve prevents the water from running back into the pump, and when the faucets are opened the water runs.

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24 HYDRAULIC AND PNEUMATIC ENGINEERING

This experiment is illustrated by means of the apparatus shown in Fig. 38. The faucet here represents the pump. Start with the tube empty except for the air in it, close the clip under the nozzle, open the faucet until the tank is full of water, close the faucet, and open the clip.

Does the water run through the siphon to the nozzle?

When the water is siphoned over a hill from a spring, the siphon is usually started by connecting it to the suction side of a pump placed on the other side of the hill in or near the house, as shown in Fig. 39.

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HYDRAULIC AND PNEUMATIC ENGINEERING 25

This is illustrated by arranging the apparatus as shown in Fig. 40; the tee branch represents the pump connection and the end branch represents the house pipe.

Close the house pipe, apply your lips to the tee branch (to represent the working of the pump) and suck air out of the siphon until the water flows, then close the tee branch and open the house pipe. Does the water flow?

In many cases the water is siphoned over the top of a hillside well to a house at a lower level and the siphon is started by means of a pump near the house as illustrated in the last experiment. Generally, however, a small storage tank of water at the top of the siphon is used to start it, see Fig. 41. The small storage tank is filled by means of a pump (not shown), or by means of a pail used to dip water from the well.

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