Fuel, of course, is the source of the power. Furnaces which are capable
of producing heat with the least consumption of fuel, tubes within the
boilers that permit the freest possible contact of the heat produced
and the water to be turned into steam, steam pipes that are flexible
and yet strong, machinery that moves with the least friction in order
to concentrate and utilise the power of the steam, and dynamos out
of which electricity is evolved, together with auxiliary pumps and
hoists and blowers and whatnot other devices to help create, control
and economise the energy, are the essential parts of an electric
power-plant. To insure economy and accuracy these are made as nearly
automatic as possible.
At one end of the furnace house there is sunk in the cement floor a
large iron scoop or tray into which cartloads of lump coal are dumped.
This scoop-shaped receptacle is also the platform of a weighing machine
so that each load is weighed. In the bottom of the scoop there is
a trap-door, which, being opened, permits the coal to drop through
between the teeth of a crusher where the large lumps are reduced,
usually to the size of a small nut.
From the crusher the coal falls into the buckets of an endless
chain-hoist and is conveyed aloft to great hopper-shaped bins which
occupy the entire space under the roof over the furnaces. Leading
back from each bin to the constantly moving grate bars of the furnace
underneath is a pipe which delivers the crushed coal to the grate bars
and distributes it evenly over their surface as fast as it can be
received into the furnace, regulated, of course, by the consumption
that is going on inside the furnace.
To accomplish this automatic feeding each set of grate bars is
constructed in hinged sections, and forms a wide endless iron belt
which revolves and carries the coal within the cavity of the furnace.
The coal crusher, bucket hoist, movable grate bars, ash collectors and
sifters, pumps, blowers, lights and all other utilities of the plant,
as well as the great travelling crane which can hoist and carry many
tons' weight--any part of the enormous dynamos--from place to place,
are operated by electricity which is generated in the dynamos.
Automatic gauges that measure and indicate, and switch-boards that
regulate the energy created and stored in the dynamos play important
parts in the economy and working of the plant and are analogous to
appetite and taste in man.