Document omdzRJ5r5kKrYX0j0MKKarX18

American Society of Heating and Ventilating Engineers Guide mti PIPING CONNECTIONS Hartford Return Connections The Hartford return connection illustrated in Fig. 7 and in piping layouts in this chapter is recognized as safer and preferable^ the use of check valves. In using this connection, the wet return connwial through the shortest possible horizontal pipe 2 in. below the nomPl boiler water line into the pipe which joins the boiler outlet and boT*i inlet on the boiler side of the stop valves. By this arrangement, jpf careless operator should close the boiler outlet valve and should for/* to close the boiler inlet valve, no water below the level of the inlet < nection to the loop could leave the boiler. Connections to Mains Fig. 8 shows two methods of taking off branches from mains on on! pipe systems. They apply equally well, however, to other systems ( ... ,, Chapter 10--Piping for1 Steam Heating Systems P&S$sS$SE$f'?''C'--o*nnections for Vapor and Vacuum Systems i WiPHgs- 14 to 19, inclusive, are illustrated some of the piping details Vhich are recommended in connection with vapor and vacuum Keating Figs-14 and 18 show methods of draining and venting the ends of supply '' mthaeinssamwehedreetaailrewthuernrebtehleowretthuernbomilaeirnwisataebrolivneetihseuwseadt.erFliinge. 19Fsighowl!s shows the method of draining the ends of long branches from supply AS" ELBOW' 'branch ____ ____ Main KXmtIE METHOD PEEfEBED METHOO Fig. 8. Acceptable and Preferred Methods of Taking Branch from Main Fig. 9. Looping Main Around Beam rlHESECCNNOONS SHOULD E AS SHOW AS PWCTICAL USING AS FEW-} \ TUBUS AS P0SS1&E. THESES SHOULD PEEFtEAHY EE NOT SMALLER THAM GIVEN N TABLE BELOW. WE SEE ----(W 4 sa FEET TO B SQ FEET.------IK 15 SO FEET OB MORE-------- 4' ECCENTRIC REDUCING (COUPLING. Fig. 11. Practical Method of Reducing Size of Main Fig. 7. THESE PIPES MAY K ANY SEE CONSKBEO PBOPEB FOB FEEDING' B01LEBS AND LESS THAN SFEAM CONNECTIONS l TABU ABOVE. Connecting Two Boilers Using the Hartford Return Connection ' up-feed piping. On one-pipe plants the branches are always made one| pipe-size larger than the risers or the radiator connections which they! serve. The method of carrying a main past an obstructing beam showii| in Fig. 9 may be used advisedly \vith any system of piping. Fig. 10 shows a detail of piping at the end of a single-pipe main oratf any point where it becomes desirable to rise for a fresh start at a higher! level, the steam rising off the top of the main and the water draining! down to the wet return below the boiler water line. If the detail shown! in Fig. 10 is used at the end of the main, an air valve must be installed! above the water line. ' Where it is desired to reduce the size of a supply main, an eccentric! fitting always must be used, as shown in Fig. 11, or a reducing elbow| must be installed, as in Fig. 12, so that perfect drainage is accomplished.] These details also apply to any other system of steam piping. A handy rule for cutting the proper length of offset pipe is illustrated! in Fig. 13. 176 Fig. 10. Practi cal Method of Dripping Main Where It Rises to Higher Level small pipe Fig. 12. Reducing Size of Main at Swing Connection TO FOOLENGTHC - UULTKAY A BY COUSWNT FOR ANGLE B. Fig. 13. Constants for Determining Proper Length of Offset Pipe mains to risers or to remote radiators. Fig. 16 shows a sediment chamber which will catch debris in any vapor or vacuum system, this being cleaned occasionally, preventing the foreign matter from stopping up or injuring the traps or other mechanisms. Fig. 17 illustrates an approved method for carrying a return main which runs near the floor, past a door. The air in the upper part of the main rises freely over the door; while the water passes in the trench under the door. Figs. 20 and 21 illustrate approved details of the return pipes leading to vacuum pumps where there must be lifts from low-lying mains up to the pump. These lifts should be avoided wherever possible. 177