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PRESSURE O R O P -P S I PER IOO FT PRESSURE D R O P -O U N C E S PER SQ IN. PER 100 FT
364
CHAPTER 26
1959 Guide
Bated on Moody Friction Factor whoto flow of condensate doei not inhibit (he flow of doom.
Rg. 22.... Basic Chart for Weight-Row Rate and Velocity of Steam in Schedule 40 Pipe Based on Saturation Pressure of 0 Psig
(With Multiplier Chart* for Obtaining Weight-Flow Rate* end Velocities of All Saturation Pressure* Bo(ween 0 and 200 Fag)
Steam Heating Systems Rg. 22 (Continued).... Velocity Multiplier Chart
365
Example of Use of Basic and Velocity Multiplier Charts.
Given:
a. Weight-Flow Kate = 6700 lb per hr. b. Initial Steam Pressure -* 100 psig. c. Pressure Drop = 11 psi per 100 ft.
Find;
o. Siee <ft Schedule 40 pipe required. 6. Velocity of steam in pipe.
Solution: The following steps are illustrated by the broken line on Fig. 22: Step 1. Enter Fig. 22 at a weight-flow rate of 6700 lb per hr
and move vertically to the horizontal line at 100 psig. Step X. Follow along inclined multiplier line (upward and to
the left) to horizontal 0 psig line. The equivalent weight flow at 0 psig is about 2500 lb per hr.
Step S. Follow the 2500 lb per hr line vertically until it inter sects the horizontal line at 11 psi per 100 ft pressure drop. The nominal pipe size is 2% in. The equivalent steam velocity at 0 psig is about 32,700 fpm.
Step 4 To find the steam velocity at 100 psig, locate the value of 32,700 fpm on the ordinate of the velocity multiplier chart at 0 psig.
Step 6. Move along the inclined multiplier line (downward and to the right) until it intersects the vertical 100 psig pres sure line. The velocity as read from the right (or left) scale is about 13,000 fpm.
Note: The preceding Steps 1 to 5 would be rearranged or reversed if different data were given.
Table 5....Weight Row Rate of Steam in Schedule 40 Pipe* at Initial Saturation Pressures of 3.5 and 12 Psig.b>0
{Weight Hw Bata Expressed in Pound* par Hoor)
Pressure Drop--Fd For 400 Ft m length
Near, ftps Size Indies
Ke Psi 0 ori Sot. press, psig
X Psi (2 ox) Sat. press, psig
K P*i W ox) Sat. press psig.
X ftl [8 oz) Sat. press, psig
KPsHl2ox) Sat. press, psig.
1 Psi Sat. press, psig
2 Psi Sat. press, psig
3.5 12 3.5-" 12 3.5 12 3.5 12 3.5 . 12 3.5 12 3.5 12
H 1
IK
iH
2 2M 3 3K
4 5 6 8
10 12
9 11 14 16 20
24
29
35,
36
43
42
50
60
73
17 21 26 31 37 46 54 66 68 82 81 95 114 137
36 45 53 66 78
96 111 138 140 170 162 200 232 280
56 70 84 100 120 147 174 210 218 ( 260 246 304 360 430
108 174 318 462
134 215 380 550
162 258 465 670
194 310 550 800
234 378 660 . 990
285 460 810 1218
336 540 960 1410
410 660 1160 1700
420 680 1190 1740
510 820 1430 2100
480 780 1380 2000
590 950 1670 2420
710 1150 1950 2950
850 1370 2400 3450
726 1200 1920 3900
800 1430 2300 4800
950 1680 2820 5570
1160 2100 3350 7000
1410 2440 3960 8100
1690 3000 4850 10,000
1980 3570 5700 11,400
2400 4250 7000 14,300
2450 4380 7200 14,500
3000 5250 8600 17,700
2880 5100 8400 16,500
3460 6100 10,000 20,500
4200 7500 11,900 24,000
4900 8600
14,200 29,500
7200 8800 10,200 12,600 15,000 18,200 21,000 26,000 26,200 32,000 30,000 37,000 42,700 52,000 11,400 13,700 16,500 19,500 23,400 28,400 33,000 40,000 41,000 49,500 48,000 57,500 67,800 81,000
" Baaed an Moody Friction Factor, where flow of condensate doea not inhibit the flow of steam. The weight-flow rates at 3.S psig can be used to cover sat. press. (ram 1 to B psig, and themteaat IS psig can be used to cover sat. press- from 8 to 18 psig with an
* The steam velocities corresponding to the weight-flow rates given in this table ean be found from the basic chart and velocity multiplier chart. Fig. 22.