Problem 17
TEE JOINT NOT AT RIGHT ANGLES
34. The Tee Joint Not at Right Angles.—The tee joint not at right angles is used for conveyor systems, and in heating and ventilating work. The abrupt change of direction in the Tee Joint at right angles causes a drop in velocity that seriously affects the working of an entire system. The greatest angle of deflection allowable in a Tee Joint not at right angles is 45° from the direction of flow as in Fig. 105. Many firms use an angle of 30°.
Side Elevation.—The side elevation should be drawn using the dimensions given in Fig. 106. The branch pipe is represented as being broken in this view, because the upper part of the branch plays no part in developing the pattern. A profile, Fig. 106, divided into sixteen equal parts, which are numbered, is now drawn. Extension fines are carried downward from each division until they meet the apparent miter line. The intersections of the apparent miter line A, B, C, etc., are lettered as shown in Fig. 106.
Front Elevation.—The front elevation. Fig. 107, should be drawn in outline. The "tee" is set at an angle of 45° to the main pipe as shown. The profile of the "tee" should be drawn and divided into sixteen equal parts. An extension line from each division of this profile is carried downward and to the right; that is, parallel to the sides of the branch.
Developing the Miter Line.—Horizontal extension lines from each intersection of the apparent miter line are carried over into Fig. 107. If a view were to be taken along these lines in the direction of the arrow, the eye would see two points, D and F for instance, on each line. But Fig. 106, the side elevation, represents such a view; therefore the intersections of the front half of the apparent miter line must each have two letters. Starting at the point A in Fig. 106, the intersections of the apparent miter line must be lettered as shown. Starting from point 1 in the profile of Fig. 106 the extension line can be traced downward to the apparent miter line, and thence to the correspondingly numbered line, dropped from the profile of Fig. 107. In like manner, the other intersections for the developed miter line are located and the curve drawn.
