Xylem Bell & Gossett Hoffman Speciality Series, Инженерный справочник данных

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42
Flow Rate Supply Pressure= 100 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
28 62 133
3 ⁄
4
62 134 290
1 120 260 544
1 1 ⁄
4
250 540 1130
1 1 ⁄
2
380 810 1700
2 750 1590 a
2 1 ⁄
2
1200 2550 a
3 2160 4550 a
4 4460 9340 a
6 13,200 a a
8 27,400 a a
Flow Rate Supply Pressure= 150 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
23 51 109
3 ⁄
4
50 110 230
1 100 210 450
1 1 ⁄
4
200 440 930
1 1 ⁄
2
310 660 1400
2 610 1300 a
2 1 ⁄
2
980 2100 a
3 1760 3710 a
4 3640 7630 a
6 10,800 a a
8 22,400 a a
Flow Rate Supply Pressure= 100 psig
(lbs./hr.) Return Pressure=15 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
56 120 1100
3 ⁄
4
120 260 2400
1 240 500 4540
1 1 ⁄
4
500 1060 9500
1 1 ⁄
2
750 1600 14,200
2 1470 3100 a
2 1 ⁄
2
2370 5000 a
3 4230 8860 a
4 8730 18,200 a
6 25,900 53,600 a
8 53,400 110,300 a
Flow Rate Supply Pressure= 150 psig
(lbs./hr.) Return Pressure=15 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
43 93 200
3 ⁄
4
93 200 420
1 180 390 800
1 1 ⁄
4
380 800 1680
1 1 ⁄
2
570 1210 2500
2 1120 2350 4900
2 1 ⁄
2
1800 3780 7800
3 3200 6710 a
4 6620 13,800 a
6 19,600 40,600 a
8 40,500 83,600 a
Flow Rate Supply Pressure= 30 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
60 130 274
3 ⁄
4
130 280 590
1 250 530 1120
1 1 ⁄
4
520 1110 2340
1 1 ⁄
2
780 1670 3510
2 1540 3270 a
2 1 ⁄
2
2480 5250 a
3 4440 9360 a
4 9180 19,200 a
6 27,300 a a
8 56,400 a a
Flow Rate Supply Pressure= 15 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
95 210 450
3 ⁄
4
210 450 950
1 400 860 1820
1 1 ⁄
4
840 1800 3800
1 1 ⁄
2
1270 2720 5700
2 2500 5320 a
2 1 ⁄
2
4030 8520 a
3 7200 15,200 a
4 14,900 31,300 a
6 44,300 a a
8 91,700 a a
Flow Rate Supply Pressure= 5 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
240 520 1100
3 ⁄
4
510 1120 2400
1 1000 2150 4540
1 1 ⁄
4
2100 4500 9500
1 1 ⁄
2
3170 6780 14,200
2 6240 13,300 a
2 1 ⁄
2
10,000 21,300 a
3 18,000 38,000 a
4 37,200 78,000 a
6 110,500 a a
8 228,600 a a
Condensate that collects ahead of a steam
trap is approximately at saturation
temperature and corresponds to the
operating pressure. As the condensate
(normally above 212°F.) drains into the
return line, it must flash to reach saturation
temperature at atmospheric pressure. The
excess Btu’s are released in the form of
flash steam in the return lines. The return
lines must be sized to handle the volume of
steam and condensate at reasonable
velocities to minimize any backpressure.
The volume of steam is normally several
times the volume of condensate and is
generally maintained at less than 7,000 feet
per minute.
The following tables are for horizontal return
lines draining to a return system. Return
lines should pitch 1
1 ⁄
2
in. per 10 ft. of
horizontal run. Select the return line size
ASHRAE
Method for
Sizing Return
Lines based on the steam operating pressure and
the allowable p/L, psi/100 ft. Selections for
100 and 150 psig steam for either a vented
return system or a 15 psig pressurized return
system such as a flash tank, deaerator or closed
return system.
Example:
A condensate return system has a
steam supply at 100 psig and the return line is
at 0 psig and not vented. The return line is
horizontal and must have a capacity of 2500
lbs./hr. What size pipe is required?
Solution: Since the system will be throttling
non-subcooled condensate from 100 psig to 0
psig there will be flash steam and the system
will be a dry-closed return with horizontal pipe.
Select a pressure drop of
1 ⁄
4
psi/100 ft. and
use a 2 1 ⁄
2
in. pipe for this system.
For these sizes and pressure losses, the velocity is above 7000 fpm.
Select another combination of sizes and pressure loss. Reprinted by permission of the American Society of Heating, Refrigeration and Air-Conditioning
Engineers, Atlanta, Georgia, from the 1989 ASHRAE Handbook-Fundamentals
a
FLOW RATE (lbs./hr.) FOR DRY RETURN LINES
Flow Rate Supply Pressure= 50 psig
(lbs./hr.) Return Pressure=0 psig
p/L, psi/100 ft.
Pipe
Size
(in.)
1
⁄
16
1
⁄
4
1
1 ⁄
2
42 92 200
3 ⁄
4
91 200 420
1 180 380 800
1 1 ⁄
4
370 800 1680
1 1 ⁄
2
560 1200 2520
2 1110 2350 a
2 1 ⁄
2
1780 3780 a
3 3190 6730 a
4 6660 13,800 a
6 19,600 a a
8 40,500 a a