Chapter 1 Introduction to Fluid Power 27
Many mechanical improvements were made
as water and windmills became prime sources of
power. These improvements included methods
of power transmission through shafts, cogged
wheels, crude gears, and cams. These devices were
needed to transmit the power and transform it into
the type of motion needed to do the desired work.
Many ingenious devices were developed that have
contributed to the body of knowledge as the world
moved toward the Industrial Revolution.
Industrial Revolution
The eighteenth and nineteenth centuries are
often designated as the period in which an “indus-
trial revolution” occurred. That period of history
produced tremendous changes in world society,
particularly in Great Britain. Great Britain had
established extensive world trade, a strong finan-
cial base, large local reserves of iron ore and coal,
and key individuals interested in the practical
development of scientific principles. These factors
combined to lead to the Industrial Revolution.
Changes during the Industrial Revolution
occurred much more quickly than those during
the Middle Ages. However, identification of spe-
cific dates or events that started the “revolution” is
not possible. It must also be emphasized that the
industrial change was not just tied to mechani-
cal devices, but involved changes as diverse as
world trade and application of scientific methods.
Nevertheless, development of new prime movers
must be considered to be the key to the Industrial
Revolution, Figure 1-17. The steam engine, inter-
nal combustion engine, and gas turbine all were
developed during the period. Unlike water and
windmills, these devices were mobile and not
dependent on local weather or terrain conditions.
Even with those new power development devices,
water and windmills continued to play important
roles in industrial power generation throughout
the middle 1800s and much later in smaller, local
and rural applications.
The use of machines instead of hand tools was
another key to the changes of the period. These
machines exceeded the capabilities of skilled
craftsmen to develop products. They allowed pro-
duction rates that met demands resulting from
expanded trade areas.
The development of manufacturing increased
the need for methods and devices to move water
and transmit power. The procedures and devices
developed to satisfy these needs are where fluid
power, as we think of it today, began to emerge.
Many of the early fluid power elements involved
pumping water from mines or for manufacturing
uses. James Watt designed steam-driven, recipro-
cating pumps that were used in the late 1700s and
early 1800s. By the mid-1800s, these pumps were
widely used. The East London Water Company
operated a unit with a 100″ diameter cylinder and
a stroke of 11 feet. By the 1870s, patents were issued
for variable-stroke, piston pumps. The centrifugal
pump was invented in the late 1600s, but was not
generally used until the mid-1800s. The jet pump
was also produced during this same period.
A key factor that allowed the development of
many practical fluid power components was the
cup seal. This type of seal uses the pressure within
the system to force a sealing collar against a shaft
or ram to prevent fluid loss, Figure 1-18. Invented
in 1795, the cup seal allowed hydraulic presses to
be built that both did not leak and could be con-
tinuously used.
Two other devices that were especially impor-
tant to the development of fluid power during the
1800s were the hydraulic accumulator and the
hydraulic intensifier. Large, weighted accumula-
tors were used to store pressurized fluid from
Figure 1-17. The steam engine provided a reliable,
portable source of power. Its development is con-
sidered one of the key factors in the development of
the Industrial Revolution.
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