FIRE ENGINES
A good motto to blazon over the doors of a fire-brigade station would
be "He gives help twice who gives help quickly." The spirit of it is
certainly shown by the brave men who, as soon as the warning signal
comes, spring to the engines and in a few minutes are careering at full
speed to the scene of operations.
Speed and smartness have for many years past been associated with our
fire brigades. We read how horses are always kept ready to be led to
the engines; how their harness is dropped on to them and deft fingers
set the buckles right in a twinkling, so that almost before an onlooker
has time to realise what is happening the sturdy animals are beating
the ground with flying hoofs. And few dwellers in large cities have not
heard the cry of the firemen, as it rises from an indistinct murmur
into a loud shout, before which the traffic, however dense, melts away
to the side of the road and leaves a clear passage for the engines,
driven at high speed and yet with such skill that accidents are of rare
occurrence. The noise, the gleam of the polished helmets, the efforts
of the noble animals, which seem as keen as the men themselves to reach
the fire, combine to paint a scene which lingers long in the memory.
But efficient as the "horsed" engine is, it has its limitations.
Animal strength and endurance are not an indefinite quantity; while
the fireman grudges even the few short moments which are occupied by
the inspanning of the team. In many towns, therefore, we find the
mechanically propelled fire engine coming into favour. The power
for working the pumps is now given a second duty of turning the
driving-wheels. A parallel can be found in the steam-engine used for
threshing-machines, which once had to be towed by horses, but now
travels of itself, dragging machine and other vehicles behind it.
The earlier types of automobile fire engines used the boiler's steam
to move them over the road. Liverpool, a very enterprising city as
regards the extinction of fire, has for some time past owned a powerful
steamer, which can be turned out within a minute of the call, can
travel at any speed up to thirty miles an hour, and can pump 500
gallons per minute continuously. Its success has led to the purchase
of other motor engines, some fitted with a chemical apparatus, which,
by the action of acid on a solution of soda in closed cylinders,
is enabled to fling water impregnated with carbonic acid gas on
to the fire the moment it arrives within working distance of the
conflagration, and gives very valuable "first aid" while the pumping
apparatus is being got into order.
[Illustration: Two Motor Fire-engines built by Messrs. Merryweather,
London. That on the left is driven by petrol, and in addition to
pumping-gear carries a wheeled fire-escape. That on the right is driven
by steam. Both types are much faster than horses, being able to travel
at a rate of over 20 miles an hour.]
As might reasonably be expected, the petrol motor has found a fine
field for its energies in connection with fire extinction. Since it
occupies comparatively little space, more accommodation can be allowed
for the firemen and gear. Furthermore, a petrol engine can be started
in a few seconds by a turn of a handle, whereas a steamer is delayed
until steam has been generated. Messrs. Merryweather have built
a four-cylindered, 30 h.p. petrol fire engine capable of a speed of
forty miles an hour. It has two systems of ignition--the magneto (or
small dynamo) and the ordinary accumulator and coil--so that electrical
breakdowns are not likely to occur. A fast motor of this kind, with a
pumping capacity of 300 gallons per minute, is peculiarly suited for
large country estates, where it can be made to perform household or
farm duties when not required for its primary purpose. Considering
the great number of country mansions, historically interesting, and
full of artistic treasures, which England boasts, it is a matter for
regret that such an engine is not always included among the appliances
with which every such property is furnished. How often we read "Old
mansion totally destroyed by fire," which usually means that in a few
short hours priceless pictures, furniture, and other objects of art
have been destroyed, because help, when it did come, arrived too late.
Owners are, however, more keenly alive to their responsibilities now
than formerly. The small hand-worked engine, or the hydrant of moderate
pressure, is not considered a sufficient guard for the house and its
contents. In many establishments the electric lighting engines are
designed to work either the dynamo or a set of pumps as occasion may
demand; or the motor is mounted on wheels so that it may be easily
dragged by hand to any desired spot.
The "latest thing" in motor fire engines is one which carries a
fire-escape with it, in addition to water-flinging machinery. An engine
of this type is to be found in some of the London suburbs. A chemical
cylinder lies under the driver's seat, where it is well out of the
way, and coiled beside it is its reel of hose. The "escape" rests on
the top of the vehicle, the wheels hanging over the rear end, while
the top projects some distance in front of the steering wheels. The
ladder, of telescopic design, can be extended to fifty feet as soon as
it has been lowered to the ground. Since the saving of life is even
more important than the saving of property, it is very desirable that
a means of escape should be at hand at the earliest possible moment
after an outbreak. This combination apparatus enables the brigade to
nip a fire in the bud, if it is still a comparatively small affair, and
also to rescue any people whose exit may have been cut off by the fire
having started on or near the staircases.
The Wolseley Motor-Car Company has established a type of chemical motor
fire engine which promises to be very successful. A 20 h.p. motor is
placed forward under the frame to keep the centre of gravity low. When
fully laden, it carries a crew of eight men, two 9-foot ladders, two
portable chemical extinguishers, a 50-gallon chemical cylinder, and a
reel on which is wound a hose fifty-three yards long. The wheels are
a combination of the wooden "artillery" and the wire "spider," wires
being strung from the outer end of the hub to the outer ends of the
wooden spokes to give them increased power to resist the strain of
sudden turns or collisions. An artillery wheel, not thus reinforced, is
apt to buckle sideways and snap its spokes when twisted at all.
England has always led the way in matters relating to fire extinction,
and to her is due the credit of first harnessing mechanical motive
power to the fire engine. Other countries are following her example,
and consequently we find fire apparatus moved by the petrol motor
in places so far apart as Cape Town, Valparaiso, Mauritius, Sydney,
Berlin, New York, Montreal. There can be no doubt but that in a very
few years horse-traction will be abandoned by the brigades of our large
towns. It has been suggested that the fire-pump of the future will be
driven by electricity drawn from switches on the street mains; enough
current being stored in accumulators to move the pump from station to
fire. In such a case it would be possible to use very powerful pumps,
as an electric motor is extremely vigorous for its size and weight.
Even to-day steam fire engines can fling 2,000 gallons per minute,
and fire floats (for use on the water) considerably more. Possibly
the engine of to-morrow will pour 5,000 gallons a minute on the
flames if it can get that amount from the water mains, and so render
it unnecessary to summon in a large number of engines to quell a big
conflagration. Three hundred thousand gallons an hour ought to check a
very considerable "blaze."
The force with which a jet of water leaves the huge nozzle of a
powerful engine is so great that it would seriously injure a spectator
at a distance of fifty yards. The "kick-back" of the water on the
nozzle is sometimes sufficient to overcome the power of one man to
hold the nozzle in position with his hands, and it becomes needful
to provide supports with pointed ends to stick into the ground, or
hooks which can be attached to the rungs of a ladder. For an attack on
the upper storeys of a house a special "water tower" is much used in
America. It consists of a lattice-work iron frame, about twenty-five
feet long, inside which slides an extensible iron tube five inches in
diameter. The tower is attached to one end of a wagon of unusual length
and breadth, and is raised to a vertical position by a rack gearing
with a quadrant built into its base below the trunnions or pivots on
which it swings. Carbonic acid gas, generated in a cylinder carried on
the wagon, works a piston connected with the racks, and on a tap being
turned slowly brings the tower to the perpendicular, when it is locked.
The telescopic tube, carrying the hose inside it, is then pulled up
by windlasses, until the 2-1/2-inch nozzle is nearly fifty feet from
the ground. The nozzle itself can be rotated from below by rods and
gearing, and the angle of the stream regulated by a rope. If several
engines simultaneously deliver their water to the tower hoses 1,000
gallons a minute can be concentrated in a continuous 2-1/2-inch jet on
to the fire.
The ordinary horsed fire engine is simple in its design and parts. The
vertical boiler contains a number of nearly horizontal water tubes,
which offer a great surface to the furnace gases, so that it may raise
steam very quickly. The actual water capacity of the boiler is small,
and therefore it must be fed continuously by a special pump. The pumps,
two or three in number, usually have piston rods working direct from
the steam cylinders on the plungers of the pumps. Between cylinders and
pumps are slots in the rods in which rotate cranks connected with one
another and with a fly-wheel which helps to keep the running steady.
After leaving the pumps the water enters a large air vessel, which
reduces the sudden shocks of delivery by the cushioning effect of the
air, and causes a steady pressure on the water in the hoses.