_The number of appliances and special devices_ used on and about a
steam fire engine is not large, as it is the aim of both designers
and builders to simplify the machine as much as possible without
diminishing its efficiency.
Fig. 434 is an appliance known as the _Siamese connection_. It is used
for stand pipes attached to the outside of buildings, etc., and also as
a detail of the fire pump. Its use is to lead off two lines of hose.
The valve shown in the figure, closes automatically in case of stoppage
of one of the engines or the bursting of the hose.
[Illustration: FIGS. 434, 435.]
Fig. 435 exhibits an approved form of _strainer_ for the bottom of the
suction pipe.
_The American steam fire engine pump_ is shown in Figs. 431 and 432.
Fig. 431 being the front view, one side of it shown in section,
exposing the interior parts for explanation, and Fig. 432, representing
the side elevation, also in section.
The pumps, which are double acting, are united in a gun-metal casting,
which forms a single body for both, and permits them to be placed much
closer as to centers than could otherwise be done. This method provides
an ample suction-chamber which is common to both.
In cross section the pump somewhat resembles a box girder. This
peculiarity of the pump’s combined form furnishes a rigid base for the
entire structure, simplifies the driving mechanism and enables it to
endure extraordinary strains without vibration.
It will be seen by reference to the cuts that any of the valves can be
easily and quickly examined, and, if necessary, replaced, by simply
removing the caps and heads.
The pump barrels are provided with removable linings, which can readily
be replaced with new ones in case the same should become worn after
years of service. These, as well as the valve seats, are made of gun
metal, no cast iron or other material subject to corrosion by water
being used in any part of the pumps.
Both the suction and discharge valves are supplied with improved valve
springs, the tension of which is, at all times, the same; and being
made of phosphor bronze, the springs retain their elasticity and will
not corrode.
The steam cylinders used in connection with this pump are of the
ordinary slide-valve type, with which most mechanics are familiar, and
are thus easily repaired when necessary. The cylinders and pumps are
detached from the boiler, and are separated therefrom sufficiently
to allow every facility for getting at each and every part. All
connections, both steam and water, are made outside of the boiler.
_The La France steam fire engine pump_ is shown in outline in Fig. 433,
which consists of a double plain slide-valve engine, operating a double
pump.
The steam piston rod of each side connects with its pump rod, by means
of square bars, two of which are on each side of the crank shaft. The
crank is operated by the cross-head through a connecting rod; the
arrangement of these parts can be seen in Fig. 433. The cross-head
guide is entirely done away with, as the stiffness of the connection
between the two piston rods takes the thrust of the connecting rod.
The pump barrel is enclosed by an outer casing. The space between
barrel and casing is always kept filled with water which is supplied
through the suction pipe.
[Illustration: FIG. 436.]
When the pump barrel is being filled with water the suction valves are
lifted from their seats, which allows the water to pass into the space
between the valve-seat plates and thence into the pump barrel.
When the pump barrel is being emptied the suction valves are closed
while the discharge valves are open, which allows the water to pass
into a triangular shaped space between the front plate and valve-seat
plates thence upward to the discharge pipe.
The suction and discharge valve of this pump being all grouped
together, it is only necessary to remove the plates which can be seen,
Fig. 433, bolted to the front of the pumps and form part of the outer
casing; these plates are in front of the pump and may be quickly
unscrewed by a ^T^ wrench.
_The Amoskeag steam fire engine_ is shown in the views (Figs. 429 and
430 on pages 128 and 130). This world widely known machine is made by
the Manchester Locomotive Works at Manchester, New Hampshire, U. S. A.
The former cut represents the extra first, first, second, third
and fourth size double steam fire engine of this make. They have
“crane-neck” frames and are arranged for horse draft and are mounted
upon Endicott’s patent platform springs. The effect of this improvement
is that the draft strain is transmitted directly from the horses to the
axles, the springs bearing no part of this draft strain.
Fig. 430 shows the “fifth” size, also with “crane-necked” frame and
made for either horse or hand draft.
The boiler used is upright and tubular in style, is made of the best
quality of steel plate, with seamless copper tubes, thoroughly riveted
and stayed; it is simple in its construction, and for strength,
durability, accessibility for repairs, and its capacity for generating
steam, has passed a most critical test. For engines of the second
size and larger, the boilers expand downwards at the crown sheet of
the fire-box, thus increasing the grate surface and consequently the
steaming capacity of the boiler.
The connections with the steam cylinders are simple, direct and of
good capacity, peculiarly accessible for repairs, and have _the great
advantage of being entirely unexposed to the air_.
The steam cylinders of the single engines are made in one casting; they
are secured to the boiler framing, and covered with a lagging of wood,
with a metallic jacket on the outside. The pump for the double engines
is made entirely of composition, and its main shell is also in one
casting. It is vertical double acting; its valves are vertical in their
action; the water-ways are free and direct, and the valves accessible,
so that examination or renewal of these parts may be quickly made. The
pump is arranged for receiving suction hose on either side, and has
outlets also on either side for receiving the leading hose.
_Self-propelled steam fire engines_ are well adapted for city service.
In Fig. 436 is shown a double extra, first size self-propelling engine
of the Amoskeag pattern. The road driving power is applied from one end
of the main crank shaft, through an equalizing compound and two endless
chains running over sprocket-wheels on each of the main rear wheels,
permitting these rear wheels to be driven at varying speeds as when
turning corners.
The driving power is made reversible, so that the engine may be driven
either forward or backward on the road at will.
The steering of the engine is effected by means of a steering hand
wheel at the front, adjusting the front axle through a system of
bevel and worm gearing, so arranged that the constant exertion of the
steersman is not required to keep the wheels in line on the road. By
the removal of a key the driving power may be disconnected from the
road driving gearing, when it is desired to work the pumps when the
engine is standing still.
MISCELLANEOUS
PUMPS
[Illustration: FIG. 437. (See page 146.)]