U EPARTMENT OF' AGRICULTURE
V "\ ~ OF PUBLIC ROADS
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IPENAL TV I'OR PRIVATE USE T. AVOID
DIVISION OF AGRICULTURAL ENGINEERING
UNITED STATES DEPARTMENT OF AGRICULTURE
BUREAU OF PUBLIC ROADS
March 16, 1925.
Mr. Ralph ~. Parshall,
Colorado Experiment Station, Fort Collins, Colorado.
Dear :Mr.
Parshall:-P. 0. BOX 180
POST OFFICE BUILDING BERKELEY, CALIFORNIA
In reply to your letter of March 11 asking as to the siphon :pipe for the Farmers Ditch Company at Boulder, I an send'inrg you a pencil sketch that is largely self-explanatory. The vertical curved entrance you will find quite easy to make and it is very efficient. If the loss of head is to be minimized, I would be very careful to filet all square corners so as to minimize entry and exit losses.
\lftan you have all your conditions aef~nitely determined you
may find that the length is so short that the intake will be submerged forall velocities, and if' this is true you will not need to :place the intake end of the steel pipe as low in the structure as is indicated in the sketch. I attach computation sheets which indicate that a single b4 inch pipe will carry 80 second-feet with a loss of about 0.5 feet, while two 48 inch pipes will accomplish the sa~e thine with a net loss of about 0.2 feet.
You will note that I have made certain assumptions as to the thicirness of walls wnicn you must verify with an understanding of the foundations and risks involved at the installation site.
This simple curved entrance yo11 will find practically as
erf lcie.nt as complicated warped surfaces. It is based on the eenera.l idea that we are making the greatest changes in velocity direction while the velocity is at its lowest point and the minimum change is taking place as the higher velocities are reached just before the water enters the pipe proper.
Very truly yours,
~@S
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