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CHAPTER XXV

ONCERNING the drawing of pip

ing, there is nothing connected with it which differs at all in principal from the work which we have already been over. Consequently, the illustration which we present, will cover the greater part of the subject.

Figs. 137 and 138 show the water piping connected with range boiler work,

E

Fig. 137.

B

the former showing wrought iron pipe, and the latter lead. In each of these illustrations, A and B represent globe valves in two positions, A being seen from the side, and B from a position where the wheel appears in front of the valve. These same positions respecting the stop cock are shown at C and D. E shows a bibb.

A simpler and quicker way of showing this work, and one that is often just as desirable, is shown in Fig. 139, A, B, and C showing respectively a globe valve, stop cock and bibb.

If it is desired to make a distinction between the hot and cold pipes, it may be done by drawing one with solid lines, such as Fig. 139 shows, and the other by dotted lines. The same effect can be obtained very satisfactorily by showing the cold pipes with blue pencil or ink, and the hot with red. We might add, by the way, that this method is often followed in making the distinction between the drainage and the venting system of plumbing work.

Comparing Fig. 137 with Figs. 140 and 141, it will be seen in the former that the fittings are made of the same diameter as the pipe, while in the latter, which show larger sized pipes, the size of the fitting is made larger than the pipe.

The latter method is usually adopted in showing steam piping, while the former is used in water piping.

In Fig. 140, A, B, C and D show respectively the ell, reducing ell, tee, and reducing tee.

Fig. 141 shows 45-degree connections, with the main, from which the connection is taken, showing sidewise, while

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Fig. 147.

will be on an angle of 45 degrees, such as the dotted line shows in the sketch.

Having put in this line, which should be done in light pencil, the centers for striking the curves of the several ells may be taken on this line.

In taking up much of the work considered in this article, we are not adhering strictly to the requirements of the plumber, but as the work of the plumber and fitter are so closely allied, this work will prove of value to the average plumber we believe.

Our readers will find plenty of good practice work in the illustrations which we have presented in this chapter, and the drawing of valves, radiators and coils will be found of special value.

T

CHAPTER XXVI

HE showing of steam pipes on floor plans is a matter that calls for attention, and in this connection we give Figs. 148 and 149. The method shown in Fig. 148 is the one which is probably most used, the pipes being represented by single lines, and the risers by circles.

The other method shown in Fig. 149 has the advantage of showing the connections of branches with the main, more in detail than the method just mentioned. A glance at the sketch will show that the tee on the main is turned at 45 degrees,

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and a 45-degree ell brings the branch level again.

Now we come to the matter of showing piping in perspective, the last point which we shall take up in this series. It is of much importance, for it will be found that it is used a great deal, and furthermore, many systems of heating are very difficult to illustrate by any other means.

To get into this subject we show several simple examples of perspective in Fig. 150.

A represents a connection which inspection will show is viewed by looking down upon the object, and from the right,

while B is obtained by looking downward from the left. Either of these two views is very common, much more so, we may say, than views obtained by looking upward upon the object. C shows a connection which is viewed from the left and on a level with it, instead of downward or upward, and occasionally is a desirable method to follow. D shows a little more difficult perspective than those preceding, and E shows valves in two different positions, in perspective.

A close study of these examples of perspective will show that the ellipses which are seen on the fittings are square with the direction of the pipe, no matter in what direction the pipe may run.

Compare F and G, which are supposed to represent the same thing. The ellipses in F are not square with the fitting or pipe, while those in G are. The result is apparent. The tee in F is distorted, while that in G is not.

If our reader will hold a piece of pipe in front of him with the end pointing toward him, that end will appear as a full circle, but if he will turn the pipe from this position gradually until it stands lengthwise instead of endwise, this circle will become an ellipse, gradually narrowing, until finally, when in a position lengthwise, no part of a circle or ellipse is to be seen, simply the square end being seen.

Perhaps this crude example will explain why, in this perspective work, the circles on the fittings appear as ellipses. In making a rule for this work we can perhaps do no better than to say that the straight lines of pipe should be first put in, in their proper directions, and the fittings connecting them put in afterward, and as previously stated, care be

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the boiler. In perspective, all vertical lines appear vertical, hence all the risers in Fig. 151 are vertical.

The line of pipe S-T is at right angles to the boiler and therefore must be parallel with the front line of the boiler, that is, horizontal. The lines A-B and K-L are of course parallel with the lines V and W of the boiler, and must therefore be drawn in that way, that is, at 60 degrees with the horizontal.

The lines of pipe shown at C, D, M and N are parallel with S-T and E-F, and are therefore drawn horizontally with the tee square.

The lines of pipe shown by G, H, P and R being on the work itself parallel to A-B and K-L are drawn parallel, that is, at 60 degrees with the horizontal.

In Fig. 151 we have lines of pipe running in four different directions in addition to the vertical lines, and we believe that this sketch will cover the ground

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Mechanical Drawing for Plumbers. Sketch Showing a Heater and its Piping.

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