Deming graphic. (Deming, N.M.) 1903-1948, 1912-12-27
PUMPS, ENGINES
AND IRRIGATION
Duty Of Water and Efficiency
OF Pumping Plants Are
Explained
Colorado Agricultural College
Says Well Irrigation is
Popular.

Letters continually come to the
department of Irrigation Engineer
ing at the Agricultural College read.
ing something like this: II wish to
install pumping plant on my land;
| wish to raise the water twenty
feet high; | want to irrigate eighty
acres Of land. What size pump
shall order and what horsepower
engine will be necessary to do the
work."
This brings up Immediately two
questions, the duty Of water and
also the efficiency of the pumping
plant. 1t may be safely stated that
one second foot of water delivered
from a pumping plant will be ample
to irrigate eighty acres Of ordinary
land and will furnish ample supply
of water to raise ordinary farm
crops upon it. In fact. we should
do better than this and should make
one second foot of water irrigate
and take care of the crops on from
100 to l20 acres Of our land. Cali
fornia farmers make one second foot
of water irrigate from 300 to 500
acres, and in time we will do the
same, but much money must be
spent upon our canals and laterals
before this can be done. So, for an
ample supply, let US say that one
second foot will irrigate eighty acres.
One second foot Of water equals
$50 gallons per minute; therefore, a
pump delivering $50 gallons per min
ute should be purchased. When We
come to figure horse power neces-
sary to raise this amount of water
twenty feet, we 60 back to the
physics we studied when we were
boys. If you will think back over
those times, think you will remem-
ber that when one pound is raised
one foot high, one "foot.pound" OF
work has been done; if that pound
is raised twenty feet high, twenty
foot.pounds of work have been done
A good sized horse. weighing from
l,4OO to 900 pounds, can do sufii
cient work to raise 550.pound
weight one foot high each second
and keep it up all day and day after
day, consequently we have uni
. for the rate of doing work which II
called the horsepower" and 1t II
equal to $50 foot.pounds per second
Our engines are all rated in hors'
mower. When one cubic foot Of wa
ter, or $50 gallons. is delivered eacl
second the weight Of this water il
ga pounds. If this is raised q
feet high we would be doing q
times 62A, or 1850 feet.pounds o
work each second. Dividing this D!
$50 we have 2.3 nearly. This
the theoretical horse power required
70 raise one second-foot of water z
feet high. Our machinery howev
er. is not perfect, for there is wor
lost in friction. of the wate
in the pipe and also in the turns an
elbows, hence it will take more tina
a2.s horse power engine to do tn
work desired. The efficiency OF a
ordinary plant will not usually ru
more than SO per cent. perhaps 4
per cent would be a better figurt
90 the 2.3 horse power represent
lust 40 per cent of the power nece'
sary, or the size of engine to orde
would be 100 times one-fOrtieth 9
2.s. which is practically 8 hors
power.
Another thing that every farme
should remember. and that Is whe
water is forced through a pipe tr
faster it travels the greater the lo'
in friction. The loss is equivalei
,...~ tho uumDllQ neat