The simplest division of the subject matter relating to this branch of
practical mechanics is that which goes back to the very earliest of
times; it is thus:
1. Hand Pumps.
2. Power Pumps.
The names indicate the dividing line between the two. The following are
more modern divisions, indicating the method of action distinguishing
each:
1. Suction or Lift Pumps.
2. Force Pumps.
3. Suction and Force Pumps.
These again may be reciprocating or rotary. The powers actuating pumps
are, in the main, as follows:
1. Manual.
2. Animal.
3. Belts.
4. Water.
5. Wind.
6. Steam.
7. Gas.
8. Electricity.
These various motors give distinct names to general classes, thus,
electric pumps, belt pumps, elevator pumps, etc. A sub-division of
titles indicating differences in construction are these:
1. Vertical Pumps.
2. Horizontal Pumps, or again
1. Single Acting Pumps.
2. Double Acting Pumps.
The list is still further extended, as pumps vary in design to suit
their several uses, and are defined as rope, chain, diaphragm, jet,
centrifugal, rotary, oscillating, cylinder. It is with the last named
with which this volume has principally to deal; cylinder pumps cause
the last given classification, as they are either single or double
acting.
A single acting pump does its work through one end of the cylinder or
barrel of the pump.
In double acting pumps the motion of the piston in one direction causes
an inflow of water, and a discharge at the same time, in the other;
and on the return stroke this action is renewed as the discharge end
alternately becomes the suction end; the pump is thus double acting.
Finally pumps may be classified with reference to particular uses to
which they are specifically adapted by their form and the materials
they are required to handle.
Pumps now raise, convey and deliver beer, molasses, acids, oils, and
melted asphalt. They also handle such gases as air, ammonia, lighting
gas and even oxygen.
In the orderly progress of the contents of the volume, it will be seen
that the main subject, occupying many pages with illustrations, is that
relating to “Steam pumps;” those having a _steam-end_ and a _water-end_
and which consist of pump and steam-motor combined. An interesting
class under Vacuum-pumps will be found, 1, the combined vacuum and
feed; 2, the combined vacuum and circulating and, 3, the combined
vacuum and refrigerating pumps.
Under Pumping Engines and the Steam Fire Engine will be found a
description of the most brilliant and fascinating of modern scientific
and mechanical achievements; these two sections relate to hydraulic
engineering in its highest development.