Document YrjwaKV1G46xVVO9ZdyQGRdvD

American Society of Heating and Ventilating Engineers Guide, 1926-27 CONDENSATION RETURN PUMPS Condensation return pumps may be of the following types: a. Automatic pumps and receivers b. Continuous operation non-automatic return pumps Volumetric Capacities of Receivers--To be not less than 3 times the maximum minute volumetric flow of condensation to be handled, measured between the "high and low water lines in the. receiver. Piston Speeds in Feet per Minute.--Not more than 10 times the square root of the number of inches in the length of stroke. The ratio between the pump displacement and the maximum vol- Table 69. Duplex Piston Type Return Pumps with Receivers Standard Pressure Size op Pump 3 X 2 X 334 4KX2^X4 534 X 334 X 5 6X4X6 734 X 5 X 6 Receiver Capacity Gallons 12 20 40 60 100 Sq. Ft. Direct Radiation ' 6000 10,500 19,500 . 30,000 45,000 Lb. Condensate per Hour 2000 3500 6500 11,000 15,000 Minimum Steam Pressure 50 40 35 35 30 434 X 2 X 4 534 X 2)4 X 5 6 X 234 X 6 6X3X6 6 X 334 X 6 Low Pressure 12 6000 20 10,000 40 120,000 40 180,000 60 290,000 2000 3500. 4000 6000 9000 25 20 15 20 25 Table 70. Centrifugal Return Pumps with Receivers Size op Pump Discharge Inches i 134 2 Receiver Capacity Gallons 40 60 100 Sq. Ft. Direct Radiation 12,000 25,500 42,000 Lbs. Condensate per Hour 4000 8500 14,000 . H. P. TO Drive i 134 2 Total Head Ft. - 25 50 50 Table 71. Characteristics of Centrifugal Pumps and Receivers Delivering Against 15 Lb. Size 101 102 103 104 105 Sq. Ft! Equivalent Direct Radiation Gal. per Min. 8000 16,000 26,000 40,000 65,000 ii 22 35 60 90 R. P. M. , Actual H. P. 1725 1725 1725 1140 1140 0.4 0.6 0.8 1.0 1.4 H. P. Motor Supplied Floor Space Shipping Weight 34 S'SW 8" 700 34 5' 3"x3' 8" 700 l 6' 5'x3' 8' 750 134 7' 6"x4' 2" 1050 2 7' 6"x4' 2" 1100 130 American Society of Heating and Ventilating Engineers Guide, 1926-27 umetric rate of the flow of condensate to be handled shall be not less than 3.0 for automatic pumps and receivers and 2.0 for non-automatic return pumps. Normal Capacities for Centrifugal Pumps.--Not less than 2. times the maximum rate of flow of the condensation to be handled. RETURN LINE VACUUM HEATING PUMPS These may be of the following types: a. Direct acting reciprocating steam driven return line vacuum pumps b. Reciprocating power driven return line vacuum pumps c. Motor driven return line vacuum pumps High pressure traps should never discharge directly into a vacuum return. An excessive amount of vapor will form due to re-evaporation of a considerable part of the hot condensation. This may cause a very Fig 42. Method of Discharging High-Pressure Apparatus into Low-Pressure Heating Mains and Vacuum Return Mains through a Low-Pressure Trap material reduction in the vacuum maintained by the pump. Fig. 42 shows a method of disposing of the greater part of the vapor of re evaporation and at the same time lowering the ` temperature of the condensate. DISPOSAL OF VACUUM PUMP DISCHARGE The discharge from reciprocating vacuum pumps of either the steam or power driven type is a mixture of water and air. Means must be pro vided for releasing the entrained air. This requires water surface area in either a tank having a large horizontal cross section or a stand pipe of enough sectional area to permit a low velocity of downward jyater flow while the entrained air is escaping to the surface against the water, current. For removal of air allow one square foot of horizontal crosssection for each 2100 lb. of water per hour.- A stand pipe with, diameterequal-to that of-the pump cylinder is usually sufficient. Wherever a suitable location may be obtained the freely vented air - 131 '. /