Document M4bmx3Ze7KyXMaJmjnE87QNOM

American Society of Heating and Ventilating Engineers Guide, 1925-26 Table 72: Size of Plain and Hydro-Pneumatic Tanks Compensation Lb. per Hr. 4000 5000 8000 10,000 16,000 24,000 34,000 45,000 60,000 Sizes of Plain and Hydro-Pneumatic Tanks For Air Separator only For Air Separator and Water Storage Diameter In. 12 12 18 18 24 30 24 36 36 42 .36 42 42 Length In. 24 36 30 48 48 48 72 60 72 60 96 72 96 Diameter * In. 24 ' 24 24 30 30 36 36 36 42 42 48 48 Length In. p 36 48 72 48 60 60 72 96 72 96 72 96 LIFT FITTINGS Lift fittings are special devices used in pairs at points in a vacuum heating system where condensation is to be lifted to a higher level. The condensation is lifted in "slugs" on the air lift principles: the slugs being obtained by the use of a comparatively small diameter vertical return with its lower end submerged in the well below the level of the horizontal return which it drains. The lower lift fitting allows the con densation to accumulate in the well below.the inlet connection until it seals the vertical passage, thus causing a slight reduction of the vacuum on the inlet side and forcing the water from the well through the vertical lift pipe to the higher level. The upper lift fitting allows the condensa tion to flow into the horizontal return without falling back into the lifting line. Lifts of 6 ft. or over should be made in steps rather than all in one rise. Steps should be used instead of."Drag" lifts through long upwardly inclined pipes. In any case the pipes between the lifts must grade down ward toward the pump. When these fittings are required, the usual places to install them, is with a suction strainer at the pump, and when step-ups occur, in the return line. STEAM DRIVEN RECIPROCATING RETURN LINE VACUUM PUMPS Volumetric displacement of the water cylinders 8 to 10 times the volumetric rate of flow of the condensate to be handled. Piston Speeds.--Not more than 20 times the square root of the number of inches in the length of stroke. 128 American Society of Heating and Ventilating Engineers Guide, 1925-26 Steam driven pumps can be economically used with steam pressures of 15 lb. or over and where the exhaust steam can be completely utilized. Where the supply of exhaust steam from engines or other sources is continuously in' excess of that necessary to supply the heating system the electric driven pump is generally the most efficient and is also pre ferable when the steam pressure is too low to operate a steam driven pump. Table 73. Direct Double Acting Steam Driven Reciprocating Vacuum Pumps Diameter in Inches Cylinder Condensation Lb. per Hr. for Pumps with Stroke Equal to Bore Direct Cast Iron Radiation Served 3 4 5 6 7 8 9 10 12. 14 16 18 20 22 24 . 26 28 30 32 34 36 510 1047 1830 2890 . 4250 5920 7980 10,350 16,300 . 24,000 33,500 45,000 58,500 74,300 92,300 112,800 135,800 161,300 189,600 221,000 254,000 1700 3490 6100 9633 14,166 19,733 26,600 34,500 54,333 80,000 111,666 150,000 195,000 247,666 317,666 376,000 452,666 537,666 632,000 736,333 846,666 Pipe Sizes Steam In. Suction In. Discharge In. A A A A Va Va % l 1 m lA iA 2 2 2A 2A 2A 3 3 .3 iA 2lA 2A 2A-3A 3-3A 3A-4 4-4A 4K-5 5-6 6-7 7 7-8 8 8-10 10 12 12 14 14 14 Vi i 1A iA lA-2 2 2 2A 2A 3 3A 4 4A *A 5 6 6 6 7 7 8 Pumps Having Unequal Stroke and Bore Stroke > Bore Capacity Factor 2.50 2.25 2.00 1.90 1.80 1.75 1.70 1.67 1.60 1.50 1.40 1.33 1.30 1.25 1.20 1.10 1.00 0.90 0.80 0.75 0.70 0.67 0.60 0.50 1.58 1.48 1.38 1.34 1.31 1.29 1.27 1.25 1.23 1.10 1.15 1.13 1.12 1.10 1.08 1.04 r.oo 0.96 0.91 0.89 0.87 0.85 0.82 0.78 The capacities given in Table 73 are for pumps having water cylinder with'the'length of stroke equal to the diameter of the water piston. The. capacities for pumps of a greater or less length of stroke may be found by use of the last two columns in this table as follows: Divide the stroke by the piston diameter and find the corresponding ratio in the column headed stroke/bore. The capacity factor opposite this in the last column is then multiplied by the capacity given in the table to give the capacity of the pump in question. Proportioning of Steam End of Reciprocating Vacuum Pumps In proportioning the steam cylinder of the pump the following formula will give results which are safe to use. A. X = A,, x (il + Pd) 129 s