RP-01638

800
700
600
500
J
400
Ê w
200 e
100
1981 1982
I I I I I I I I I
A S O N D J F M A
MONTH
Fig. 8. Performance characteristics of handpump PK 001S in field test: (1) volumetric efficiency; (2) water head;
(3) water delivered per day; (4) cumulative (total) work output (m4 = m3 (volume) x m (lift)); (5) percentage wear of
top wooden bushing (0°); (6) percentage wear of bottom wooden bushing (9 0°); (7) percentage wear of top piston
ring; and (8) percentage wear of bottom piston ring.
and the average volumetric efficiency for the
period between monitoring visits. The average
volume of water delivered per day varied
from handpump to handpump as well as for
the saure handpump at different times of the
year. It is interesting to note that the average
volume of water delivered per day was higher
when the water head was greater (which
coincided with the dry season for the particular
district).
The total (accumulated) work output was
computed as the product of the average
volume of water delivered per day and the
average water head for the period between
monitoring visits. The total work output for
different handpumps varied considerably
either because some handpumps were used
more than others or because of a difference in
water head. One would expect the general
wear and tear of the handpumps to be more
dependent on the total work output rather
than calendar time.
Wear
Although wear measurements were made
on a number of components, significant wear
50