Table 3-2.—Computations and Measurement for a Y Connection.Figure 3-55.—True Y.LAYOUT OF A TRUE YIn laying out pipe for the fabrication of a true Ywithout the use of templates or tables, a full-sizeddrawing of the intersection (fig. 3-55) should be made.‘he intersection of the center lines of the three pipeswill locate point B, and lines from B to theintersections of the pipe walls will locate points A, C,and D. From these points the pipe maybe marked forcutting. Miter cutting, followed by suitable beveling,is necessary in preparing the pipe for welding.TEMPLATE LAYOUT FORTRUE Y BRANCHESAND MAIN LINESInlaying out a template for a true Y, a drawing ofthe intersection should be made, as shown in figure3-56, view A. After drawing the lines of intersection,the same essential methods as for other templatesare followed. Note that here it is suggested theequally divided semicircumferences are moreconveniently placed directly on the base line. Thedistances from the base line to the line ofintersection plotted on the unwrapped base linedetermine the template.ORANGE PEEL HEADA number of different types of heads are used inwelded pipe construction. Here, we are interested inone general type, the ORANGE PEEL, since it willoften concern you in your work. A main advantage ofthe orange peel is that it has high strength in resistinginternal pressure.If templates or tables are not available for makingan orange peel head, a reasonably accurate markingcan be secured by the following procedure for layingout a template.The number of arms to make an orange peel headshould be the minimum number which can be easilybent over to form the head. Five arms and welds arethe recommended minimum for any pipe; thisnumber should be increased for larger sizes of pipe.Dividing the circumference by 5 is a good methodfor deciding the number of arms, provided, there areat least 5.To lay out the template, draw the side and endviews (fig. 3-57). Divide the pipe circumference inview B into the same number of equal parts as it isplanned to have welds, and draw the radial lines o-a,o-b, and so on. Project the points a, b, and so on, inthis view.3-23

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