I N D U S T R I A L A N D ENGINEERIXG CHEMISTRY
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Vol. 18, No. 10
Starch Wastes
the maximum grind usually occurs, the process was not satisfactory. Measured in terms of total organic nitrogen I n the early days of the starch industry in this country present in the waste, it seemed impossible to treat satispractically everything from corn except the starch was factorily a waste containing more than 30 parts of nitrogen wasted. Large deposits of hulls have been known to collect per million. in rivers below starch factories. When this was declared a Further experiments were made diluting the waste with nuisance the starch manufacturers arranged to dry and water from the drainage canal, and experiments were made sell it for feed. Oil, a t first a waste product, has become a with sprinkling filters. Dilution with water from the drainstandard food, and that part which cannot be used in food age canal was not entirely satisfactory, possibly because is suitable for the manufacture of soap, The water in which the sludge was out of condition before dilution was attempted. the corn was steeped, a t first a waste, is now evaporated The disposal of wastes on sprinkling filters could be acand adds a very valuable constituent to the feed. complished a t the rate of 500,000 to 750,000 gallons per acre The water used in washing the ground corn and separating per day. A stable effluent was obtained the year around. starch and gluten constitutes the principal part of the 1vast.e There was some trouble from pooling, which would necessiat the present time. Large quantities of water used in the tate an allowance of rest periods in planning a commercial condensers contain no organic waste and can be passed into plant. Preliminary treatment in a settling tank with a a stream or returned to a water supply without harmful Dorr clarifier or an Imhoff tank afforded no advantage over results. A number of years ago, when asked to make rec- treatment of the raw material on sprinkling filters. As a .ommendations concerning the disposal of waste from a result of the experience with the activated sludge and sprinkstarch factory, the evaporation of the wash water was care- ling filters during 1924-25, i t was recommended that the fully considered. The dried residue is of the same compo- concentration of the waste be reduced within the plant. It sition as dried steep water and would be a valuable constit- was proposed that water be removed from the process and uent of food, but it was considered that the cost of evapora- then returned to the process a t a point earlier in the flow and tion of the large amount of water would be too great to allow in such a way that it could leave the system through the ;the evaporation to be carried out practically. I n 1920 steep water into the feed. the Sanitary District of Chicago and the Corn Products Preliminary experiments were promising and modifications Company began a series of experiments to determine the were adopted which will eventually so reduce the amount best method of disposing of the waste. Previous experience of organic matter that only a small purification plant, probindicated that evaporation would not be feasible. ably of the sprinkling-filter type, will be needed. The activated-sludge process had been found suitable It is reported that a t the Penick & Ford plant at Cedar for the disposal of packing-house wastes of similar organic Rapids schemes have been adopted in which nearly all concentration and therefore seemed to give promise of suc- the waste is utilized, leaving less than 0.5 per cent of the cess. Preliminary tests were made with waste water from weight of the corn to be wasted to the sewer. the gluten settlers and the starch settlers. alone, and with Conclusion varying proportions of condenser water up to the total waste from the plant. Dilution of the concentrated waste The history of the disposal of organic trade wastes has in most cases shown profit to the industry. It should be strongwith condenser water was found necessary. During the summer and during periods of minimum ly emphasized that it is better to use a waste with profit grind of corn, the activated-sludge method seemed to be very in a plant than to throw it into the sewer to be treated satisfactory. During cold weather, during which period at great expense in a sewage disposal plant.
An All-Glass Circulating Pump for Gases' By Frank Porter, D. C. Bardwell, and S. C. Lind FIXED NITROGEN RESEARCH L A B O R A T O RWY~, S H I N G T ODN , C
HE electromagnetic pump described herein was devised
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some time ago in the laboratory of the Bureau of Mines in Washington, especially for the circulation of electrolytic hydrogen-chlorine mixture. Its description was postponed to accompany a n account of the experiments in which it was used. These experiments will be described elsewhere in the near future, b u t t h e details of the pump are now given in order to make it available without further delay. This is rendered more urgent by the appearance of a description by Francis2 of a more elaborate type of construction of this pump, which appears to have several disadvantages in comparison with our original, on which Mr. Francis' design was based. Description of Pump The solenoid A operates the glass piston R within the tube C , with which it makes a close but free fit in its rise and fall 1
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Received June 4, 1926 Fuel, 5, 39 (1926).
through 3 cm. The core consists of a soft iron rod ( 5 cm. long and 0.2 em. in diameter) sealed in a glass tube, D, and fastened by means of lead glass to the inside of the piston near its top. The iron rod should be fixed in the glass tube (by de Khotinsky cement). The ball and socket valves F and F' are hollow glass spheres (about 0.25 cm. in diameter and about 25 mg. in weight) making a ring contact with the sockets. The lower socket was ground by means of a rod, the end of which was a hemisphere of slightly larger diameter than that of the valve. The upper socket, to avoid weakening, was not ground. The capillary stems from which the small hollow spheres were blown should be sealed off long enough to prevent the balls from turning over. h water jacket G is placed between the solenoid and the pump to maintain an even temperature. To move the piston the solenoid is supplied by direct current of about 0.5 ampere from a 110-volt circuit, which is interrupted three times a second by an electric oscillating relay (metronome type). A 50-watt lamp is connected
I S D C S T R I A L S N D ESGINEERISG CHE-VISTRY
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across the break so that the current is never completely interrupted but oscillates between about l/3 and '/z ampere. The piston then never falls to the bottom of the tube but floats on the changing magnetic field like a cork on waves of water. The capacity of a pump of these dimensions is about 15 liters per hour under a water head of 0.25 cm. The pump will force gas against a head of 3 or 4 cm. of water without losing more than 50 per cent of capacity. Advantages
The advantages of this pump relative to the type of construction used by Mr. Francis appear t o be the following:
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1-The use of a metal spring to prevent the piston from striking the bottom is not permissible in corrosive gases This object can be more easily accomplished by the residual current method By adjusting the solenoid up or down the lower dead space can be reduced to a small and exact minimum. 2-Grinding the walls of the piston and cylinder to obtain a better fit is very undesirable on account of the greater friction between the ground surfaces. This forced Francis to reduce the contact area by narrowing the piston except a t two contact rings, which entails a n increase of slip and consequent loss in capacity. 3-Placing the upper ball socket near the top instead of the bottom of the piston will perhaps make no difference in free circulation, but against a head where some compression takes place the first arrangement produces less pressure and hence lowers the capacity. 4-The use of a pendulum as circuit interrupter, especially a slow one, seems very disadvantageous from the standpoint of capacity, &-The construction of Francis is complicated by a n annular iron core which had to be fitted rather carefully t o the glass parts and by other elaborations which do not appear to have added to the efficiency of the pump, since his capacity of about 4.5 liters per hour is less than one-third of the capacity of the present pump (15 liters).
The Thomas Gas Calorimeter' Factors Affecting Its Precision, Flexibility, and Reliability By R. A. R a g a t z a n d 0. L. Kowalke ~ ~ N I V E R S I T OYF u ' I S C O N S I X ,
Description of Thomas C a l o r i m e t e r
HE Thomas gas calorimeter is designed to give automatically and continuously a record of the heating value of a gas. I n general, the instrument may be described as a continuous-flow calorimeter, in which gas is burned a t a steady rate and the heat of combustion is absorbed by a stream of air flowing countercurrent, to the products of combustion. Figures 1and 2 show it's construction and operation. Three meters, geared together and driven by the same motor, are immersed in a large tank in which a constant water level is maintained by means of a bucket pump and weir over-flow. One of these meters measures the gas whose heating value is to be determined, another measures the air t o be used in absorbing the heat of combustion, and a third meter measures the air necessary for combustion. The gas to be tesbed, supplied preferably a t 3, pressure of 3 to 6 inches of water, is admitted to the calorimeter through
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1 Presented tinder t h e title "Factors Affecting t h e Precision, Flexibility, a n d Reliability of the T h o m a s Recording Gas Calorimeter" hefore the Division of Gas a n d Fuel Chemistry a t t h e 71st Meeting o f the American Chemical Society. T u l s a . Okla., April 5 to 9, 1926.
MADISOS. \?'IS.
a pressure-reducing orifice, and enters a small expansion chamber. On the cover of this chamber is a bleeder flame, which consumes gas a t a rate sufficient to clear the supply pipe and prevent any considerable time lag in the heating values registered, and also serves t o reduce the gas pressure on the inlet side of the gas meter to atmospheric. Upon leaving the gas meter the gas is delivered to a chamber, where it is thoroughly mixed with the necessary primary air for combustion, supplied by the combustion air meter. The mixture of gas and air is then delivered to the burrier unit, where it rises through a central tube and is burned a t the top, forming a small flame. Secondary air to insure complete combustion is admitted to the flame from the combustion air meter through a second tube concentric with the first. The products of combustion are deflected downward and paythrough the annular space between the secondary air tube. arid a third tube, the heat iiiterchanger. -1s the products of combustion pass downward they give up their heat to a stream of air which is flowing in the opposite direction along the outqide surface of the heat-interchanging tube. The products of combustion and the heat-absorbing air travel in
