PUMPS 503 
‘ing water during the inward stroke. A bucket pump is also single-acting, 
discharging water during the outward stroke. By combining these two a 
p-acting pump is obtained, and this has two valves only. Fig. 804 
ows a compact form of combined plunger and bucket pump,* designed 
by Mr. Arthur Rigg. P is the plunger, and B the bucket. D and S are 
he delivery and suction air chambers respectively. The valves are of the 
annular seated ring type, provided with rubber-packed stop sockets. 
_ __ The area of the cross section of the plunger is half that of the barrel. 
Hence, during the up stroke, half of the water raised by the bucket goes 
' to fill the space left by the plunger, the other half going to the delivery 
: During the down stroke the plunger displaces the other half of 
the water raised by the bucket. 
_ 437. Continuous Delivery Pump for High Pressures.—For charging 
N . 
SSS 
Co a 
—_ 
SS : 
SSS 
a 
= 
~ SS Y 
illiam 
fe 
Md 
= N 
N 
SSS 
\N ted 
fF 
~ Lj a" 3 6 
Fig. 805. 
hydraulic acumulators, in which the pressure of the water may be from 
700 to 7000 lbs. per square inch, the type of pump shown in Fig. 805 is 
* The Mechanical Engineer, January 18, 1908. 
