« НазадПродовжити »
second floor enter, faces toward the front, in which case, we have the view which appears. The two vent tees also face the front, so that the tee branch does not appear, merely the circular form of the end of the branch.
Again, the upper fitting in Fig. 47, through which the vent line enters the stack, stands with its branch facing the front, and does not show the true shape of it, such as we have previously given in a preceding chapter.
As we have already stated, in making these drawings, we must be able to show fittings and fixtures in any position that we happen to meet, and while it is best to show them to the best advantage, it is al. most impossible to show every feature of a drawing of any extent, as we would desire.
CHAPTER IX E have previously shown the positions, as seen from the side, and from proper forms for construct the front. The front view of this fixture, ing some of the common will be found rather difficult to draw, and
fixtures. To these add in to make it as easy as possible, we have Figs. 48, 49, and 50, the urinal, slop dotted the centers of the principal curves hopper, and refrigerator. In these, besides used in constructing it. By placing the showing the fixture itself, we have shown compasses on the different centers, and its connections also. We think this a good seeing which curves would probably be idea for the reason that some of our struck from the different points, we think
it can be worked out satisfactorily.
In practicing on this work, it may be advisable, as we have previously suggested, to work on a larger scale, if the
The Drawing of a Slop Hopper. younger and more inexperienced readers may thereby be gaining a knowledge of sanitary methods, while gaining a knowledge of the subject of plumbing drawings.
The three sketches above mentioned are presented as practice exercises, and interested readers cannot do better than to put in a good allowance of time in working on them.
In Fig. 48, the urinals are shown in two
Drawing of Refrigerator and Connections.
scale on which plans are illustrated is too small to work easily.
In drawing the front view of the urinai. it will be noticed, by the way, that the fixture is in such a position that the waste is carried directly back. In this case, we might have dotted the waste to the floor, and the back air to the partition, but have preferred to show it in the way that it appears, which we believe will be clear enough for all purposes. There are many places where it is necessary to show part of the work by dotted lines, the dotted lines, of course, always signifying that the work thus shown is behind a wall or other obstruction, but the writer's opinion has always been that in this line of work, dotted lines do not add to the appearance of a drawing, and that it is better not to show them, unless the drawing will be made less clear by omitting them. Up to the present point we have confined ourselves entirely to lead and cast iron work. If we are to be able, however, to draw different kinds of work as it is presented to us, we shall need to know how to show wrought iron piping, not only on supply work, but on back airing. After what instruction has been given on cast iron work, there is not a great deal additional to be given on wrought iron. In Fig. 51, we give two methods of showing fittings, and also the two positions in which valves are usually seen. A side view of the valve shows its true shape, while in an end view the wheel handle and body represent it. In Fig. 52 18 also given a sketch showing errors likely to be made, such as giving too wide a sweep to the curve of an elbow, and in making tee branches too long. A glance at the it. tings themselves will show wherein the errors mentioned exist. As to a choice between the use of the beaded fittings and the plain fittings, we believe the former will be found the easiest to draw. The reason for this is that the diameter of the fittings and the diameter of the pipe are usually made the same, while the plain fittings to show as fittings, must have a greater diameter than that of the pipe, and this difference between the laying out of the two styles of fittings means less work on the beaded style.
For this reason, the writer usually pre.
Drawing Showing Urinals in Two
Two Methods of Drawing Fittings.
All Fittings Drawn With Ends Square. fers to use this fitting in the drawing of work in which water pipe is to be drawn.
branch taken off the main back air where it offsets, comes out of the tee straight toward us, and then bends off at an angle of 45 deg., then comes out straight toward us again, and then runs horizontally. The bends used on this branch are in such a position that their true shape can. not be seen. If the beginner has difficulty at any time in seeing how different fittings appear when placed in certain positions, let him take the fittings themselves and place them before him in such positions as are required. In doing this, however, he must remember to draw whatever object he has before him, with the element of perspective entirely elimi. nated. We have referred to this before, but a cautionary word at this point will not be out of place. It will be noticed that all the fittings of Fig. 53, whether wrought iron or cast iron, are drawn with their ends square across, and not curved as they would usually appear in perspective. Occasionally a part of the work will have to be shown in such a way, that a certain amount of perspective will have to be used, but for one unpracticed in its execution, it is a difficult matter to make such work look well, and errors on such work are very likely to destroy the ap pearance of an otherwise excellent drawing. We are ready now, we believe, to take up complete elevations of different work, including both drainage and supply, and this we shall do in the next chapter.
Sketch Showing Errors Likely to be Made. but in the case of wrought iron back air work, is inclined to use the plain fitting, as shown in Fig. 53, in which is represented back airing, including the main and the several branches. It will be noticed that fittings are shown in several different positions. For instance, the