1. Single power pumps,
2. Duplex power pumps,
3. Triplex (triple) power pumps,
4. Quadruplex, etc. Where the sizes still
further increase they are named from the number of barrels or water
cylinders, but when of much larger size than the Triplex they come
under the classification of pumping engines.
Where power can be had from a shaft in motion there is no pump so
economical as the power or belt driven pump. This fact is shown by the
rapid increase in the number of applications of this type of pump: the
reduced cost of manufacture in making the teeth of the gear wheels, the
use of automatic machinery, the production of interchangeable parts
have tended to produce a high grade of machine at an attractive price.
The energy expended in operating the power driven pump is obtained
at the same economy as that required by the machinery in the mill
or factory, and as a modern automatic cutoff engine will develop
a horse power with considerable less steam than the direct acting
steam pump the cost of the power required by the power driven pump
is correspondingly less; it participates in the economy of the steam
engine using from one and a half pounds of coal to five or six pounds
per H. P. per hour.
For this reason the power driven pump is oftentimes the more
economical, and especially where shafting is adjacent to the location
of the pump, or can be conveniently arranged by simply adding another
length of shafting with the necessary pulleys, or even by cutting
suitable openings through the walls for the belts.
_Single, duplex and triplex power pumps_ are described and illustrated
upon the succeeding pages; power pumps are built with one, two, three,
four or five cylinders and for either high or low pressure or general
service, and their sizes, capacities, and the materials they handle are
no more numerous than their combinations in erection.
The portion of this work devoted to power pumps should be especially
interesting and instructive to the attendants operating steam,
compressed air and power driven pumps. Particular attention has been
given to _single-cylinder steam pumps_ because of the great variety of
steam-actuated valves to be found in practice, each differing from the
other in one or more essential features.
It is due very largely to the numerous designs of steam valves,
that difficulty has been encountered in managing single-cylinder
pumps as successfully as those of the duplex type, the similarity of
construction in the latter type, even in minor details, being much more
marked.
The successful operation of a pump depends to a great extent upon
the intelligence displayed in its management, and an engineer can
scarcely hope to obtain quiet and smooth running pumps and freedom from
breakdowns and perplexing delays except by a thorough knowledge of the
details of construction and operation.
It must be remembered that _power pumps_ are to be illustrated and
explained in a class entirely excluding _steam pumps_; the latter are
pumps in which the moving force is steam.
_Electric Pumps_ are properly power pumps in which the moving force is
_electricity which is conducted to the pumps by wires_.