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| The European Industrial
Revolution also relied upon heavy capacity lifts in the factories
and foundries manufacturing the metal products shipped throughout
the world, and also used in large quantities on the home front.
Such factories utilized huge cranes with multiple sheaves and chains,
powered by large diameter cylinders. Manufacturers out of the large
pumping stations' sphere of operations used on-site generators of
steam power. All engineers within the confines of the Industrial
Revolution knew well the application of Pascal's Law even if they
could not quote it -- "pressure from a small piston against another
larger in piston area provides the latter with more lifting power
but less speed." |
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Sir William Armstrong,
an eminent British engineer, developed a crane in 1884 to lift stone
in his Yorkshire quarry. A hilltop reservoir, providing water supply
for his town, was the power source. The cylinder, almost horizontal,
was bored true and fitted with a piston, crosshead and sheave running
in a line on guides. The extreme end of the frame was fitted with
two similar sheaves and shafts set one above the other. A chain,
deadended at the bottom, led up and over a vertical iron post and
extended an arm to a lifting hook
(Graphic Source: Elevators by Jallings) |
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The London Hydraulic Power System, the largest in the world,
provided an unfailing water pressure output throughout the most
dense industrial and commercial areas of the metropolis -- energy
for cranes, hoists, presses, artesian wells, theater curtains,
stages and lifts for passengers and freight. Lord Armstrong had
led the pioneering work in the mid-1800s, but it took 30 years
for experiments with the supply of water under pressure before
a trial three miles of piping was operational. The pumping station
in Manchester, modeled after those in London, generated 1,000
psi, a pressure London engineers had hoped for. In the capitol
city, pressure of 450 psi was guaranteed at the usage site. In
Manchester, 750 psi was guaranteed. Neither city charged a fee
unless water was metered through the private main, providing economies
not found with other systems.
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| At the British docks,
speed of lifting was sacrificed for heavy-duty capacity as indicated
in these two graphics. The cylinders were robust, driving multiple
sheaves and chains to provide "slow but sure" cargo handling. |
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When the output pressure of the central power or the private
plant was too low for industrial press use, and multiple sheaves
and chains were not practical, an "intensifier" was
utilized. This mechanism consisted of a ram with differential
cylinders arranged so pressure could be increased to the extent
desired. Intensifiers came in various sizes depending upon the
size of the press, and the pressure required. Intensifiers, sometimes
called, "jiggers" were periodically used on water hydraulic
elevators in England.
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| The pressure at the
British central steam power plants was maintained by an accumulator,
consisting of a vertical ram weighed down with tons of slag,
or iron plate, to produce the required pressure to the mains. Almost
fifty feet high when fully charged, they were familiar sights adjacent
to the huge steam plants. The graphic depicts such a large diameter
ram, loaded with iron plate and housed in a brick silo. |
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| Where increased pressure
was required over that provided by the central steam plant, private
accumulators were installed. That pictured had an outer shell of
bricks and a poured concrete interior from which iron-bar supports
extented to a plate at the top of the piston. As we shall see in
another gallery, the intensifier and accumulator also played a part
in the evolution of the water hydraulic passenger elevator, although
the loads to be lifted were lighter. It must be kept in mind that
of all the devices powered at the turn of the century by the LHPC,
industrial lifting devices outnumbered passenger elevators by three
to one! |
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| In the U.S., Craig
Ridgeway & Son Company of Coatsville, Pennsylvania sold steam-operated
hydraulic loading dock lifts in the horse and wagon era. The manufacturer
stated in his brochure, "This lift will do the work of a half dozen
men, save thousands of dollars and can be used by the greenest of
help who cannot hurt themselves or the machine no matter how careless
they become. There are never any repairs and nothing can put the
Steam-Hydraulic-Lift out of service but the boiler blowing up." It
is understandable that the Boiler Inspectors, as a specialty, came
into being and standards set for them and the owners, before Elevator
Inspectors were considered. |
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