INDUSTRIAL AND ENGINEERING CHEMISTRY
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friction due to increased pipe length increases. This being the case, the velocity head would decrease still more, for it is proportional to the square of the velocity. Curve 9 (Figure 5 ) shows the relation of increase in pipe length to the total actual effective head. We see here that, although the pipe length is increasing, the total actual effective head is decreasing, whereas theoretically it should increase, for the friction head increases with increase in the Iength of pipe. The reason that the total actual effective head decreases with increase in length of pipe may be that velocity, hence the velocity head, is falling very rapidly, thus nullifying the effect of the increase in the head due to the pipe length. This may be shown if curves 8 and 9 are interpreted with reference to each other. Curve 10 (Figure 6) shows friction loss (in feet per 100 feet of pipe) to increase with gallons pumped per minute. The friction factor has been taken as that of water for concentrations up to 1.57 per cent for one-inch, clean, smooth, steel pipe. The behavior of a falling sphere through pulp suspensions of this concentration is about the same as that of water (IO). 16
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15 ‘C,
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Vol. 25, No. 3
and friction, commercial design for low concentration of pulp will be largely based on utilization of the mass of scientific information based on water. This appears logical and is in agreement with the known facts. For higher concentrations, factors d e r i v e d from the e x p e r i e n c e of designers of pulp mills and pumps, and of engineers operating pulp mills must be relied upon. Since these tests were made in 1923, some data on pumping pulps in largesize commercial iron pipes have been obtained, based on pulp pumped and power consumed by pumps. T h e s e l e a v e a gap for small pipes, and the data above stated conform to what one would expect for such small pipe sizes (1, 3, 6). FIGURE 6. PLOTOF CURVE10
I S i S ~
1 3 25 +-v
“2
r
I l T e IO$
qa
100
110
120
I30
140
150
I60
FIGURE 5. PLOTOF CURVES8
AND
110
110
9
ACKNOWLEDGMENT The writers acknowledge the suggestions and information given by many pulp and paper mill superintendents and engineers, and engineers having to do with producing pumping and pipe equipment for the cellulose industry.
(Concentration constant = 0.81 per oent)
LITERATURE CITED
Pitot tubes are not applicable for determining friction factors because the pulp fibers adhere to the entrance of the tubes or interfere with admission of the suspension. It is suggested that experiments be performed to study effect of (1) varying the construction of Pitot tubes to determine if, by use of large orifices, they can be adapted to pulp suspensions; (2) using a pump of determined brake-power efficiency and a variable-speed, direct-connected motor, to determine rate of discharge with variation of power input; (3) variation due to concentration of the commercial pulps; (4) variation due to kind of pulp; (5) variation due to kind and size of pipe (wrought iron, drawn steel, brass, copper, cast iron, spun cast iron, wood, copper, and commercially available alloys) ; and (6) length of pipe and fittings. Much of this, superficially, appears simple, but actually much .time and expense are involved. Until more scientific data become available on pulp flow
(1) Allis-Chalmers Co., Bull. 1649 (1930). (2) Annis, R. R., Paper Mill Wood Pulp News, 51, 49 (Feh. 25, 1928). (3) Cameron Steam Pump Works (subsidiary of Ingersoll-Rand Co.), Cameron Hydraulic Data (including International Paper Co. data), pp. 15-18 (1925). (4) Cameron Steam Pump Works, Hydraulic Data, Union Engineering Handbook, pp. 91-164, Union Steam Pump Co., Battle Creek, Mich., 1921. ( 5 ) Hiscox, G. D., “Hydraulic Engineering,” p. 82, N. W. Henley Co., New York, 1908. (6) Hydraulic SOC.,Standards, 6th ed., 1930. (7) Klosson, M. M., Am. Pulp and Paper Mill Superintendents’ Assoc. Year Book, pp. 173-6 (1932). (8) MacNeille, Paper Mill Wood Pulp News, 50, 20 (July 16, 1927). (9) Morris Machine Works, Bull. 148, 4, 5 (1932). (10) Tang, Tao-Yuan, Univ. of Maine, Thesis 668.8 T 15G (1924). R E C E I V E D November 3, 1932. Presented before the Division of Cellulose ChemiQtry at the S3rd Meeting of the American Chemical Society, New Orleans, La., March 28 to April 1, 1932.
Production of Parchment-Like Membranes from Cultures of Slime-Forming Microorganisms J. R. SANBORN, International Paper Company, Glens Falls, N. Y.
I“
investigation of the microorganisms involved in theAN formation of pulp and paper mill slimes, the author’ has emphasized the diversity of the slime flora and the heterogeneity of the viscous materials produced. Among the isolations certain yeastlike forms, belonging to the genera Oidium and Monilia, occurred prominently. These organisms develop with great rapidity in carbohydrate-rich media, producing doughy and somewhat rubbery growths. Either potato decoction or extract of groundwood, with the addition of glycerol, dextrin, or glucose, may he employed. 1 Sanborn,
J. R., J . Bad., 83, 70 (1932); t o be published (1933).
The production of satisfactory parchment-like membranes from these slime growths has been achieved by comminution of the material in water, deposition of the slime particles upon the sheet-forming substratum with the aid of an aspirator, and lubrication of the resulting membrane by means of a glycerol and mineral oil treatment. The slime particles coalesce to form a continuous, uniform, semi-transparent membrane. The final process was completed by drying in a steam hot-plate sheet drier. RECEIVED February 13, 1933:
