Document yp2mnqEaeVRNBXR8ynMJke67X

522 CHAPTER 21 1955 Guide giving a perfect swing joint when connected to the vertical riser or radia tor connection, whereas the preferred connection does not give this swing without distorting the angle of the pipe. Runouts are usually made about 5 ft long to provide flexibility for movement in the main. ' Offsets in steam and return piping should preferably be made with 90-deg ells, but occasionally fittings of other angles are used, and in such cases the length of the diagonal offset will be found as shown in Fig. 38. Dirt pockets, desirable on all systems employing thermostatic traps, should be so located as to protect the traps from scale and sludge which 3 gate VALVE TO LOW PRESSURE STEAM MAIN SAME SIZE AS TRAP TAPPING HIGH PRESSURE TRAP ______ -r 'r> > c |M X 11 _U WHOLE COUPLING. INSIDE PIPE SCREWED INTO COUPLING AND TANK WELDED BEFORE COUPLING IS WELDED TO STEEL PLATE ' HALF COUPLING WELDED TO SIDE OF FLASH LEG 7 X GATE VALVE SAME SIZE AS TRAP TAPPING HIGH PRESSURE CONDENSATE RETURN A o _j iVI 5 b. LOW PRESSURE -- TRAP OIRT POCKET - SAME SIZE AS HIGH PRESSURE RETURN MAIN .: STEEL PLATES WELDED TO PIPE TOP AND BOTTOM SEE TABLE FOR THICKNESS ''HALF COUPLING WELDED TO SIDE OF FLASH LEG ^ X HALF COUPLING AND GATE VALVE FITTINGS TO BE >25 LBS. UP TO 80 LBS. PRESS.- 4*S>2E Fig. 43. Flash Leg Installation fob 80 psi Maximum Steam ITT PnticciTDV Con densate per Hr.. Lb at 70 Psi 200 300 700 1500 2500 4000 8000 15000 Table 13. Dimensions Applying to Fig. 43 Traps HP Side Plats Flash Leo, IPS A Ft. Bc In. In. D In. E In. F In. G In. Taics ness. In. 21-80 |31-70 31-70 161-80 161-80 61-80 ft |61-80j 2j ftjo-20| AO-15; 110-151 LO-151 10-151 lft0-15; lftlO-15 4 4 4 5 8 10 n3 3 3 4 68 68 68 6 10 3 3 3 4 i 4 4 14 4 a u u 43 1 5 6 10 4 1 2 H 6 6 12 5 H 21 H 6 6 12 5 2 3 2 6 8 14 6 3- 3 3 1 1 38 1 1 i Steam Heating Systems ''Runout below Root PLAN 523 Fig. 44. One-Pipe Radiator Connections will interfere with their operation. Dirt pockets are usually made 8 in. to 12 in. deep, and serve as receivers for foreign matter which otherwise would be carried into the trap. They are constructed as shown in Fig. 39. On vapor systems where the end of the steam main is dripped down into the wet-retum, the air venting at the end of the main is accomplished by an air vent passing through a thermostatic trap into the dry-return line as shown in Fig. 40. On low pressure or vacuum systems, the ends of the steam mains are dripped and vented into the return through drip traps opening into the return line. A float and thermostatic type trap is recommended for dripping steam mains and risers as indicated in Figs. 41 and 42. The dripping of high pressure mains, or of equipment using high pressure steam into low pressure or vacuum returns, is generally accomplished by the use of a flash tank or flash leg into which the high pressure trap is arranged to discharge. This tank provides the required space for the flashing from "igh temperature condensate to low pressure steam to take place. The low pressure steam therein generated is passed directly to the low pressure steam mains, and the condensate is discharged through a second trap to the