Coal-Mine Ventilation Factors Page: 58
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58 COAL-MINE VENTILATION FACTORS
TABLE 17.-Pressure-loss tests to determine the effect of varying the space between
the cars
FIVE CARS ON 7-FOOT CENTERS (COUPLED), 2B-350 TO 2B-315
Pressure loss, Comparison of car
Air inch of water loss
volume,
Test sheet No. Date, cubic
1923 feetto Equiva-
per Observed Loss due Ratio to lent feet
minute loss to cars pressitre of clear
pressure entry
732_ --.-------------------------------Aug. 7 17, 130 0. 0215 0. 0099 1. 77 286
731 --------------------------------...........................................do.... 28, 550 .0565 .0252 1.62 270
730 --. - ....-- do .... 39, 970 .1103 .0510 1.67 288
729 ----------- --........ -------------...........--- .... do.. 51,390 .1772 .0809 1.60 281
FIVE CARS ON 15-FOOT CENTERS, 2B-350 TO 2B-283
736------------.- -----.---------------- Aug. 8 17,130 0.0244 0.0128 2.29 370
735.... --------------------------------................................do 28,550 .0654 .0341 2. 19 365
734... --------------------------------do. 39,970 .1271 .0678 2.22 383
733 -- - ...--------------------------------do.... 51,390 .2059 .1096 2.17 381
FIVE CARS ON 25-FOOT CENTERS, 2B-350 TO 2B-243
737 --------------------------------Aug. 8 17, 130 0.0296 0.0180 3. 21 520
738 ..-------------------------------_do 28,550 .0690 .0377 2.42 404
739 - --------------------------------___do 39,970 .1353 .0760 2.49 429
740 - --------------------------------do 51,390 .2240 .1277 2.53 444
FIVE CARS ON 35-FOOT CENTERS, 2B-350 TO 2B-203
744 _------------------------------- Aug. 8 17, 130 0. 0254 0. 0138 2. 47 399
743 --- - --------------------------------do.... 28,550 .0681 .0368 2.36 394
742....------------------------------------- do--- 39, 970 .1355 .0762 2.50 431
741 ....--------------------------------_do.... 51,390 .2152 .1189 2.36 414
FIVE CARS ON 40-FOOT CENTERS, 2B-360 TO 2B-193
659 - ------------------------------- .. June 1 17, 130 0. 0265 0. 0151 2. 70 436
658 ----- -__-----------------------------_--- do..__ 28, 550 .0683 .0394 2. 53 422
657. _- - _--------------------------------do.... 39,970 .1290 .0726 2.38 410
656 .... - __--------------------------------do..__ 51, 390 .2168 .1239 2. 45 431
664 ...._ -------------------------------June 8 17,130 .0261 .0147 2.62 425
663...--------------------------------do.. 28, 550 .0699 .0410 2.63 439
662 ... __ _.--------------------------------do-__ 39,970 .1334 .0770 2.52 435
661 ...---------------------------------do.__ 51,390 .2220 .1291 2.56 449
FIVE CARS ON 45-FOOT CENTERS, 2B-350 TO 2B-163
745. .-------------------------------Aug. 8 17,130 0.0244 0.0128 2.29 370
746 .... -_ _-------------------------------_ do..__ 28, 550 .0648 .0335 2.15 359
747 ....---------------------------------do..- 39,970 .1296 .0703 2.30 397
748 ....---------------------------------do.... 51,390 .2129 .1166 2. 31 406
The results given in Table 17 are not as consistent in each group
of tests as those considered in preceding tables. Test 737 is the
only one to be definitely discarded, however, as considerably out of
line with the rest. Considered on the basis of equivalent feet of
clear entry, there appears to be a tendency for the pressure loss to
increase with increasing velocity. This tendency is not definite and
uniform enough to be taken into account, however, and the results
of each group are averaged.
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Greenwald, H. P. & McElroy, G. E. Coal-Mine Ventilation Factors, report, 1929; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc12463/m1/64/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.