Document BR53xGX4GQaw5dJ2k2wvbNev8
American Society of Heating and Ventilating Engineers Guide, 1926-27
Table 72. Size of Plain and Hydro-Pneumatic Tanks
Compensation Lb.
per Hr.
4000 6000 8000
10,000
16,000 24,000
34,000
45,000
60,000
Sizes of Plain and Hydro-Pneumatic Tanks
For Air Separator only
Diameter In.
Length In.
For Air Separator and Water Storage
Diameter In.
Length In.
12 24 24 36 12 36 24 48 18 30 24 72 18 48 30 48 24 48 30 60 30 48 36 60 24 72 36 72 36 60 36 96 36 72 42 72 42 60 42 96 36 96 42 72 48 72 42 96 48 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 should be 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.
134
American Society of Heating and Ventilating Engineers Guide, 1926-27
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 Water
Cylinder
Condensation Lb. per Hr. for Pumps
with
Stroke Equal . to Bore
Direct
Cast Iron Radiation
Served
Pipe Sizes
Steam In.
Suction In.
Discharge In.
3 510 1700 34 134 34
4
1047
3490
34 134
l
5
1830
6100
34 2
134
6
2890
9633
34 234
134
7
4250
14,166
34 234-334 134-2
8
5920
19,733
34 3-334
2
9
7980
26,600
34 334-4
2
10
10,350
34,500 l
4-434
234
12
16,300
54,333 l
434-5
234
14
24,000
80,000 134 5-6
3
16'
33,500
111,666 134 6-7
334
18
45,000
150,000 134 7
4
20
58,500
195,000 134 7-8
434
22
74,300
247,666 2
8
434
24
92,300
317,666 2
8-10
5'
26
112,800
376,000 234 10
6
28
135,800
452,666 234 12
6
30
161,300
537,666 234 12
6
32
189,600
632,000 3 14'
7
34
221,000
736,333 3 14
7
36
254,000
846,666 3 14
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 1.00 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.
135