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THE DESIGN OF A MACHINE TO POWDER MILK.
Submitted by
William Hoyt Young Jr.
and
Kenneth Reynold Sutherland.
June, 1922.
DEPARTMENT OF MECHANICAL ENGINEERING MASSACHUSETTS INSTITUTE OF TECHNOLOGY
May, 1922.
Gentlemen:
In compliance with the requirements for a
degree of Bachelor of Science from the Massachusetts
Institute of Technology, we submit for your approval,
the following thesis on "The Design of a Machine to
Powder Milk".
Respectfully,
Signature redacted
Signature redacted
,-ay we acknowledge our gratitude for the help and
advice given to us during our work on the thesis by the
following men: Professor E. F. Miller Doctor L. W. Smith Professor C. W. Berry Professor R. S. Williams Professor G. B. Haven Professor R. H. Smith.
INDEX
SUBJECT PAGE
Statement of the problem . . . . . . . . . . . . . .
1
Method of procedure. . . . . . . . . . . . . . . .
.1
Selection of materials . . . . . a . . . . . . . . .
2
Different designs. . . . . . . . . . . . .. . . . 2
Method of driving drum . . . . . . . . . . . . . . .
3
Conclusions. . . . . . . . . . . . . . . . . . , . .
Appendix "A"
Picture of finished machine.
Appendix "B".
THE DESIGN OF A MACHINE TO POWDER L1ILK
STATEMENT TE PROBLIT. The machine was designed, at
the request of Dr. L. W. Smith of the "On Shore" Depart-ment of the Boston Floating Hospital, for the purpose of powdering human breast milk. In order that this milk, when powdered, might retain all of its original
nourish-ing qualities, it was necessary for the machine to be
designed to conform to certain conditions which would keep alive, in the powdered form, an essential vitamine. The process was to be one of forced evaporation; the milk to be sprayed en a surface heated to 2500
Fahren-heit, allowed to remain there ten seconds and then scraped off. Inasmuch as the machine was to be built upon completion of the design, it was advisable to use
as many standard parts as possible in order that it might be constructed quiokly and cheaply.
t-HOD
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PROCEDURE. The idea conceived, was to have acylinder, heated from the inside, upon which the milk might be sprayed, and to revolve this cylinder at a
speed which would permit the completion of the whole process within the time taken by the drum to make one half a revolution. Before the design was attempted
Professor C. W. Berry of the Mechanical Engineering
Department was consulted regarding heat flow and Prof-essor R. S. Williams of the Chemical Engineering Depart-ment was consulted concerning the best material from from which to make the drum. It was decided that since the rate of heat flow would vary as the milk changed from liquid to powdered form , it would be impractical do design a piece of apparatus which would give such close adjustment and that the better way would be to attempt to keep the inside of the cylinder at the con-stant temperature of 2500 Fahrenheit.
Wrought iron was chosen as the best material from which to make the drum, inasmuch as it would be least apt to corrode or be affected by any chemical action of the milk.
Two designs were started, one to heat the drum by steam, the other by electricity, but after a talk with
Mr. Wise, Chief Engineer of the Simplex Wire and Cable
Company, it was decided to abandon the electrical method as impractical and efforts were concentrated on the first method. The design and method of operation was as
follows: A steam tight drum was made by welding
dard cast iron flanges to a piece of wrought iron pipe.
To these flanges were boltedr specially designed cover plates which permitted the cylinder to be supported in bearings and also allowed for injake and exhaust steam pipes surrounded by jam nuts and packing. The bearings
were mounted on wooden blocks bolted down to some two inch planking, which in turn was mounted on the standards
of an old Thor washing machine. Screwed to the under side of the planking was an electric motor with reduction gears and a pullpy supported in the proper bearings and the drive to the drum was by means of a belt passing
over this pulley and over the flange en one end of the
drum. Against the front of the cylinder was held a
rub-ber roller which allowedaa small pool of milk to be held
between its surface and the surface of the drum and
diametrically opposite from this roller was fastened a knife for scraping off the powder. A small tank connect-ed to a distributing pipe just over the roller makes it possible to feed the milk into the pool at a slow rate and therefore leave the machine unattended for a con-siderable length of time. As the operator stands in front
of the machine - the side where the milk is applied - the
cylinder turns toward him and down at the rate of three
revolutions per minute. The roller spreads a thin film of milk hn the surface of the cylinder, which goes down
and then up to the knife on the other side, where it is
scraped off. Any milk which does not immediately adhere to the cylinder after passing under the roller, may be caught in a pan and vsed over again. The powder is caught in a pan on the other side and preserved. Steam
up to forty pounds gage pressure may be had, and since
there is a given temperature corresponding to every pressure, a chart has been furnished with the machine,
so that by reading the pressure gage attached to the apparatus it is possible to know at exactly what temp-erature the steam is entering and to make any adjustments necessary.
The original design was submitted and given to a machinist. In the process of manufacture, he welded the cast iron flanges to the wrought iron pipe and after the machine was set up, the first admittance of steam caused
the welding to crack because of unequal expansion. To
overcome this, it was decided to cast the drum and
flan-ges in one piece from cast iron. It was also found that due to the fact that the belt passed over one of the flanges, it became heated and consequently expanded,
causing slipping. A wider Velt of different material was tried, but had the same fault, so the belting was dis-carded and a specially designed sprocket was built to fit over the bolts at one end. The small pulley was re-moved and a sprocket put in its place and the chain drive proved successful.
The appended picture in conjunction with the assem-bly and part drawings, will serve to show any details not made clear in the description.
COLCLJUSION. In view of the fact that the machine as lastly described is installed in the basement of the "On Shore" quarters of the Boston Floating Hospital, and has been successfully used to powder milk, leads the designers to believe that their work has been accomplished.
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