Vol. 20, No. 9
INDUSTRIAL AND ENGINEERING CHEMISTRY
924
which exists between f and (Dup/p)-that is, the relation which will fit the curve thus obtained-because there is no real need for such a relation; the curve is far more usable. The individual measurements from which the curve was made are tabulated below. Each point on the curve, which corresponds to a line in the table, is the result of four closely agreeing measurements. D
U
P/P
Fl./sec. L b s . / c u . f l . / v k a 10.87 ' 6i70' 22.50 6570 29,40 6570 44.34 6570 61.22 6550 10.22 951 16.56 903 31.67 925 44.85 947 62.50 951 90.50 946 956 121.00 5.20 11280 21.50 11430 35.60 11720 11870 43.80 9.76 6150 29.10 6150 42.32 6150 58.60 6150 6860 0.1184 6.18 6860 2 2 , SO 6860 36.42 6850 47,24 20.18 945 945 44.60 945 72.60 945 112.40 a Viscosity in English units.
Inch 0.0449
DW/P
f
3220 6660 8690 13020 18020 436 67(! 1310 1905 2660 3855 5200 2630 11080 18720 23300 2690 8050 11680 16150 504 1858 2962 3830 2260 5000 8140 12580
0.0479 0.0232 0.0183 0.0123 0.0088 0.4190 0.2730 0.1390 0.0900 0.0720 0.0470 0.0290 0.0610 0.0152 0,0093 0.0079 0.0609 0.0245 0.0136 0.0103 0.3120 0.0967 0.0643 0,0442 0.0644 0.0308 0.0168 0.0162
0.
r
0.4
03
I
I
lYlllll XIIII
I
I I
I I I Ill1
I IIIIII
I
I
I
I I l l II
GAS
FLOWING Air
Hz
CO? CH4
Air
H 2
Discussion
Since the curve was obtained by the calibration of a large number of flowmeters, the process can be reversed and the values from the curve used instead of the calibration when a flowmeter is desired. This method of calculation is not a general substitute for calibration, but in those very numerous cases where the approximate velocity at which the gas is to flow is known and where the total pressure on the gas and the temperature are fairly closely known, a series of calculations requiring about 30 minutes may be substituted for a calibration requiring 3 or 4 hours with no sacrifice in accuracy. This method of calibrating a flowmeter would consist in
the selection of a capillary tube of about 1 meter length and of suitable diameter. The diameter must then be determined accurately. Since the density and viscosity of the gas are known, several values of velocity covering the range expected may be assumed and corresponding values of f read from the curve. By substituting these in the Fannin equation, values of Ah corresponding to each of the assumed velocities may be obtained and a curve of pressure drop us. velocity may be drawn. The close approach to a straight line obtained in the curve justifies the assumption that it could be extrapolated on either end if necessary. This assumption is further justified by the fact that other similar curves, made for different conditions of flow, do not show any sharp inflection except when the critical velocity of the fluid is reached. It is very rare that gases are handled at such low velocity. However, it is hardly likely that in ordinary work there will be any need to extrapolate the curve here given. The sizes of the tube and velocities used cover pretty generally the range likely to be met in practice. It will be noted that the minimum rate of flow is less than 100 cc. per minute while the maximum is nearly 25 liters per minute.
Treatment of Missouri River Water for Locomotive Use' H. H. Richardson MISSOURIPACIFICRAILROAD Co.,ST. LOUIS,Mo.
ISSOURI River drains wholly or in part ten statesColorado, Iowa, Kansas, MinnesotJa,Missouri, Montana, North Dakota, South Dakota, and Wyoming. The drainage area of 528,850 square miles, which is approximately one-sixth of the area of the United States, is larger than that of any other of the tributaries of the Mississippi; in fact it comprises 43 per cent of the total of the Mississippi basin. For a considerable part of the distance from Omaha to Kansas City, Mo., and from Kansas City to St. Louis, the Missouri Pacific Railroad parallels the course of the Missouri River, taking advantage of the water-grade line. It is to be expected that on this rail distance of 491 miles the major 1 Presented before the Division of Water, Sewage, and Sanitation Chemistry at the 75th Meeting of the American Chemical Society, St. Louis, Mo., April 16 t o 19, 1928.
source of water supply both for the cities and the railroad would be the Missouri River. Although not subject to the rapid fluctuations in quality that are common to smaller rivers nor to serious industrial trade waste pollution, the quality of the supply is unsatisfactory for steam-making purposes on account of the scaleforming and suspended matter present. The total hardness averages approximately 14 grains per gallon and total dissolved solids, 20 grains. The seasonal variations in quality are more or less regular, the maximum dissolved solids and minimum suspended matter occurring in December and January, and the minimum dissolved solids and maximum suspended matter in the late spring and early summer months. The spring floods of 1927 caused an unusual increase in hardness during May and June. There was also an un-
September, 1928
INDUSTRIAL Ah-D EXGINEERING CHEMISTRY
precedented increase in suspended matter, which gave considerable trouble a t the city filtration plants and at the company’s plants using raw rirer water, which will be mentioned later. I n line with the Missouri Pacific program, inaugurated in 1905, of improvement of quality of locomotive water supplies by the elimination of the largest possible amount of impurities, complete lime-soda ash water-softening plants have been installed a t ten of the thirteen points where Missouri Rirer water is used, as shown in Table I. Table I-Water-Softening LOCATIOX Omaha, Nebr. Nebraska City, h-ebr. Atchison, Kans. Leavenworth. Kans. Kansas City, Kans. Kansas City, M o . Waverly, M o . Lupus, M.0. Jefferson City, N o . Hermann, Mo.
F’Ian# t s of Missouri Pacific Railroad SOURCE TYPEOF PLANT City City City City C1ty City Railroad Railroad City (raw) Railroad
Contmuous Continuous Continuous Continuous Continuous Continuous Continuous Intermittent Continuous Continuous
Untreated city water is yet being ueed at Independence, Myrick, and Booneville, Mo., and a t certain minor watering points in the terminals a t Omaha and Kansas City. The plants a t Jefferson City and Hermann are equipped with the International Filter Company’s variable-type chemical feed apparatus. The other continuous-type plants use Roberts water motors for chemical proportioning. The total water softened and chemicals used during the year 1927, except for Hermann which plant was placed in operation in December, is shown in Table 11. for 1927 a t Company’s Water-Softening S t a t i o n s SODA SODIUM WATERSOFTENED LIME ASH ALUMINATE Gallons Pounds Pounds Pounds Omaha 50,227,000 99,140 65,730 3,809 Nebraska City 10,091,000 21,067 13,870 1,022 Atchison 66,087,000 144,158 90,111 7,953 Leavenworth 16,280,000 27,525 17,978 1,156 Kansas City, Kans. 5,530,000 11,098 6,363 Kansas City, Mo. 161,610,000 249,120 153,588 44,894 Waverly 17,567,000 34,975 18,360 1,320 Lupus 11,191,000 22,957 11,272 ... Jefferson City 140,995,000 244,679 135,751 37,493, Total 479,578,000 554,716 513,023 97,649 Total cost of chemicals, $18,482.41; average cost per thousand gallons, $0 0386. T a b l e 11-Data
STATION
.... .
Sodium aluminate was used throughout the year a t Kansas City, Mo., and Jefferson City. I t s use was started a t the other plants, except Kansas City, Kans., and Lupus, in June. At these two points the consumption is relatively small and the plants are adequate to handle the treatment satisfactorily without its use. Matter i n S a m p l e s of R a w Water a t Three Plants (Figures in grains per U. S. gallon) JEFFERSON 1927 WAVERLY LUPUS CITY January 40.6 50.3 43.4 February 52.3 63.5 67.0 March 154.7 120.9 161.0 April 317.1 311.1 290.5 May 425.1 417.8 422.3 June 442.2 396.9 437,5 Tulv 344.3 272.4 307.8 :August 212.1 190.5 223.2 September 211.3 211.7 226.9 123.7 127.5 137.2 0ct ob e r Sovember 63.7 59.5 69.2 December 39.1 42.1 22.0 Average 190.4 198.4 202 9
Table 111-Suspended
Monthly averages of semiweekly tests of raw and filtered water at Omaha, Atchison, Kansas City, &‘Io., and Jefferson City during 1927 show a range in hardness of the raw water from 10 to 22 grains per gallon and for the treated water from 0.8 to 4.9 grains. The average for the raw water for the year was from 13.1 grains per gallon a t Jefferson City to 14.8 a t Omaha, and for the treated water 2.9 a t Omaha, 2.7 a t Atchison, 1.5 a t Kansas City, Mo., and 2.4 a t Jefferson City.
926
The plants a t Warerly, Lupus, Jefferson City, and Hermann are furnished raw river water without prior sedimentation or clarification. Composite monthly samples from the semiweekly raw-water samples for the first three stations which were in operation throughout the year showed the suspended matter present in the amounts given in Talde 111. The maximum amount is shown for the month of June a t Waverly, 442.2 grains or approximately 63 pounds per thousand gallons. At Jefferson City on May 19 the suspended matter reached 876.2 grains. At Kansas City the city plant reported on May 16 a maximum of 1330 grains, which was the highest on record. During this flood period in the latter part of May, the company’s softening plant a t Jefferson City was unable to remove the very finely divided suspended matter and it was necessary to make certain changes in the plant. Prior to 1926 the Jefferson City plant used the clarified city water supply. The plant consisted of a 3O-foot diameter by 60-foot tank and was designed for a softening rate of 30,000 gallons per hour, with an upflow rate of 5.6 feet per hour and a 4-hour retention period, which gave very satisfactory service. In order to take advantage of a much lower price for raw, unclarified water as pumped from the river, the company installed in 1926 a 40-foot diameter by 60-foot tank designed for handling the raw river water a t a rate of 50,000 gallons per hour with an upfloar rate of 5.3 feet per hour and a retention period of 8 hours. The 30 by 60 tank was retained for additional storage to permit the plant to be handled on a single 10-hour shift. This arrangement worked very satisfactorily until the floods of May, 1927, when the turbidity reached an abnormal maximum, and muddy water was delivered from the softening plant. The rate of softening was reduced to 35,000 gallons per hour, which gave an upflow rate of 3.7 feet per hour with a retention period of 11.6 hours, a t which rate fairly satisfactory performance was again obtained. However, this lowered rate necessitated an additional pumping shift. To avoid this extra shift it was decided to use both the 40 by 60 and the 30 by 60 tanks for softening purposes. Since they were located adjacent to each other, it was necessary only to install a dividing weir in the mixing box a t the top of the 40 by 60 tank to divert a proportionate amount of the mixed raw water and chemicals to the two tanks. Both tanks were already equipped with downtake tubes and sludgecollection systems. After this change and the installation of floating outlets in both tanks, the 50,000 gallons per hour softening rate gave an upflow rate of 3.4 feet per hour and a retention period of 10.4 hours, which should adequately take care of any similar recurrence of highly turbid water. The nine plants which were in operation throughout the year removed a total of approximately 794,700 pounds of scale-forming matter from the 479,578,000 gallons of water used for locomotive purposes, Based on the generally accepted and conservative value of 13 cents per pound of scale-forming matter removed, these plants effected an indicated gross saving in 1927 of $103,311. I n addition, the plants a t Waverly, Lupus, and Jefferson City removed a total of approximately 5,022,000 pounds of suspended matter. On the territory between Omaha and Kansas City considerable trouble was formerly experienced with leaky flues and stay bolts, resulting in engine failures and making it necessary to hold locomotives in for inspection and repairs about three days each month. Since complete treatment of water supplies on this territory, the leaky conditions have been practically eliminated: during 1927 there was not an engine failure due to leaky flues. The life of flues and fire boxes has been increased over 200 per cent and the boiler work has been reduced approximately 55 per cent.
