Square to Round
The transition piece shown in figure 8-18 is used to
connect round and square pipes. It can be seen from
both the development and the pictorial drawings that the
transition piece is made of four isosceles triangles,
whose bases connect with the square duct, and four parts
of an oblique cone having the circle as the base and the
corners of the square pipe as the vertices. To make the
development, a true-length diagram is drawn first.
When the true length of line 1A is known, the four equal
isosceles triangles can be developed After the triangle
G-2-3 has been developed, the partial developments of
the oblique cone are added until points D and K have
been located Next the isosceles triangles D-1-2 and
K-3-4 are added, then the partial cones, and, last, half of
the isosceles triangle is placed at each side of the
development.
Rectangular to Round
The transition piece shown in figure 8-19 is
constructed in the same manner as the one previously
developed except that all the elements are of different
lengths. To avoid confusion, four true-length diagrams
are drawn and the true-length lines are clearly labeled.
Connecting Two Circular Pipes
The following paragraphs discuss the developments
used to connect two circular pipes with parallel and
oblique joints.
PARALLEL JOINTS.—The development of the
transition piece shown in figure 8-20 connecting two
circular pipes is similar to the development of an oblique
cone except that the cone is truncated The apex of the
cone, 0, is located by drawing the two given pipe
diameters in their proper position and extending the
radial lines 1-11 and 7-71 to intersect at point 0. Fit
the development is made to represent the complete
development of the cone, and then the top portion is
removed. Radius settings for distances 0-21 and 0-31 on
the development are taken from the true-length diagram.
Figure 8-18.—Development of a transition piece—square to round.
8-14
