Data Requirements
for Estimates
In order that the proper type and size of wheel may be determined,
definite information and answers to the questions below should be
furnished
1. HEAD OR PRESSURE
State the vertical distance in feet between the level of the water
at proposed inlet of pipeline (ditch, flume or forebay), and the floor
level where water wheel will be placed. This measurement is termed
the static or gross head. When feasible this should be determined
with a surveyor's level.
2. WATER QUANTITY
State the amount of water available in cubic feet per minute, cubic
feet per second, or gallons per minute. If the quantity is given in
miner's inches, state the head, in inches, to the center of the opening
of the measuring box; otherwise an exact understanding of the amount
cannot be obtained owing to the different interpretation as to quantity
placed on the miner's inch in various localities.
State maximum, minimum and average water quantity available and over
what period of time is the stream flow at its lowest. Do not state
the quantity as being sufficient to fill a pipe of any given diameter,
as such information is unreliable.
The simplest and most accurate- method for determining the quantity
of water flowing in a stream is by the use of a weir, as described
below. Proceed as follows: Get a plank of sufficient length and width
so as to cross the stream and intercept it (see Fig. 7A). Saw a rectangular
notch in this plank at the middle, the length of the notch being about
two-thirds of the width of the stream. Place the plank across the
stream as shown in Fig. 7A. The plank must be firmly anchored and
all leaks stopped. Bevel the sides and bottom of the notch sharply
up-stream. Drive a peg near the center of the stream and about 4 feet
up-stream from the plank. Bring the top of this peg level with the
bottom of the notch, using a straight edge and a carpenter's level.
Next measure with an ordinary rule the depth of the water over the
top of the peg, as is shown in Fig.7A. From this depth, in inches,
the number of cubic feet flowing in the stream per minute can be obtained
from the accompanying table. Suppose the weir to be 72 inches long,
and the depth of water over the stake to be 11 5/8 inches, follow
down the left-hand column of the figures in the table until you come
to 11 inches; then run across the table on a line with the 11 until
under 5/8 on top line, you will find 15.85. This multiplied by 72,
the length of weir, gives 1141.2, the number of cubic feet of water
passing per minute.
3. STORAGE
Can the water be impounded by a dam or reservoir? If so, state the
storage capacity in cubic feet.
4. PIPE LINE
What length of pipe line is necessary to secure the gross head? Measurement
should be made along the slope of the ground where pipe will ultimately
be laid. If the pipe line is already installed, state the length of
each diameter and whether of wood, stave, riveted or lap-welded steel.
Where a pipe line is already conveying water for other purposes, as
to existing wheels, state the total water quantity that is being used.
5. DRIVEN MACHINERY
The speed of, and power required for, operating the driven machinery
should be specified. State if an electric generator, compressor, mill,
etc., is to be driven. Where the Pelton Wheel is to drive the machinery
by belting, state the diameter, face and speed of driven pulley.
6. POWER FLUCTUATIONS
How often does the load fluctuate and what amount of power is constantly
thrown on or off?
