A few months ago there was exhibited, in the society's reading room, a
working model of an application to railway working of what the
inventor calls "division of the mass." In causing a body, moving at a
high velocity, to communicate motion to another at rest, or moving at
a lower velocity, he splits one of them up into parts all the more
numerous, and therefore tenuous, as the difference in velocity is
greater; and this is accomplished by causing one of the parts to take
the form of a brush composed of metal fibers.
In applying this principle to the transmission of motion for driving
machinery, a disk, fitted with segmental brushes, is slid laterally
along the shaft, so that the fibers come into contact with radial
projections on a second disk; and, although the contact is made
instantaneously, the action is exerted gradually, owing to the
flexibility of the fibers. That is to say, the full power is
communicated without any shock.
A similar arrangement, but with one of the disks fixed, serves as a
brake for arresting motion, and this again without shock, but with
gradually increasing action. Where space is very much circumscribed,
the clutch and the brake may be combined, by fitting a disk with
brushes on one side, and projections on the other, so that it may be
brought by a lever against a second disk, for transmitting motion, and
against a third, fixed, for stopping it.
Safety appliances for arresting the descent of mine cages, in the
event of the rope breaking, have hitherto depended upon the entrance
of claws into the guides, or the clipping of the latter, or the
wedging of the cage between the guides.
In this application of the system, the guides of the shaft are fitted
with corrugated iron plates, and the sides of the cage with steel
brushes. In the normal state of working, the brushes are kept clear of
the guides, but, should the rope break, a small brush, fitted on a
sector, constantly rubbing against the corrugations of the guides,
aided by a spring or counterweight, brings the main brushes into
contact with the guides by a link arrangement, like that of the
parallel ruler, thus arresting the cage, and holding it suspended
until the brushes are gradually relaxed, for "braking" the cage slowly
down to the next landing.
Many attempts have been made to cause a locomotive, running at full
speed, to exert such a mechanical action as would set a signal to
danger, so as to protect the train from another following in the rear.
By fitting the engine with a steel brush, attached to the axle boxes,
so as to preserve a uniform height with respect to the rails, a
stationary lever may be gradually moved, so that the signal is set at
"danger" without shock. Moreover, by means of another brush, in the
event of the engine being turned upon the wrong line, a lever may be
made to shut off the steam, apply the brakes, blow the whistle, or
move an index on a dial, recording a neglect of duty, or may exert
these four actions simultaneously.
All the above applications of this principle--"the division of the
mass"--have been tested experimentally, the last named by the model
above referred to. The clutch arrangement has transmitted six horse
power from a petroleum motor, making 200 revolutions a minute, to a
dynamo making 2,000 revolutions, while applications to industrial
purposes are now being made, both in this country and in Belgium. The
inventor of the system is M. Raymond Snyers, Ingénieur des Mines, du
Génie Civil, et des Arts et Manufactures, of the Louvain
University.--_Journal of the Society of Arts._
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STEAM GENERATOR OF SERPOLLET BROTHERS, PRODUCING STEAM
INSTANTANEOUSLY.
The explosibility of a steam generator may be measured by the relation
of its total capacity to its vaporizing power. The old fashioned
generators and some of the modern ones are so constructed as to
contain from fifteen to twenty times more water than they are able to
vaporize within one hour. Thus a great quantity of heat is obtained
and a uniform pressure assured, but the steam-generating apparatus is
costly, heavy, and cumbersome; it requires a long time before the
necessary pressure is obtained, and the generator is only suitable for
a stationary installation and where it can uninterruptedly work for a
long period of time. Besides, the enormous quantity of hot water under
pressure constitutes a constant danger, and the explosion of a steam
generator with boiler tubes becomes a real disaster.
In order to satisfy the requirements which have newly arisen in
connection with navigation, locomotion, small motors and apparatus
which need for their working an intermittent supply of steam, it
became necessary to modify the construction of steam boilers, to
augment their heating surface, to diminish their residue of water, and
to gradually construct so-called _inexplosible_ apparatus, of which
the Belleville boiler forms one of the most characteristic prototypes.
In trying to reduce the inexplosibility to the utmost, Messrs.
Serpollet Brothers have succeeded in constructing a type of boilers
which may be called _absolutely inexplosible_, and this result has
been obtained by reducing the capacity of the boiler to practically
_nil_, thus rendering the explosibility also _nil_, for under the
circumstances the relation between capacity and vaporizing power
becomes itself _nil_.
[Illustration: FIG. 1.--INSTANTANEOUS VAPORIZATION BOILER OF MESSRS.
SERPOLLET.
1. General view of boiler (experimental arrangement). 2. Cross
section of boiler (natural size). The line A B indicates, at
somewhat exaggerated scale, the cross section of the interior
empty space of the boiler.]
The method employed for this purpose by Messrs. Serpollet is an
extremely simple one. A cylindrical steel tube of convenient diameter
and sufficient thickness is rolled flat at a temperature below the
white heat of the metal, and the last touch of the rollers is given to
it when already cold. By this means a flat tube is obtained, the empty
interior space of which looks in a cross section (Fig. 1, No. 2) like
a black line not thicker than a hair, and measures from 0.1 to 0.3
millimeter. This tube is finally rolled up in the form of a spiral, or
left straight, according to the use to be made of it, and put into an
appropriate furnace (Fig. 1, No. 1). To either end of the tube a joint
is attached, the one for the purpose of admitting the water, the other
for admitting the steam.
When under these circumstances the tube has been heated to a high
temperature in a convenient fire box, the water which has been pumped
into it, by a feed pump fastened to one of its extremities, is
instantly changed into steam and escapes at the other end at a
pressure and in a state of dryness depending on the working conditions
of the apparatus. The ingenious and really original and novel idea in
this invention is this flattened tube, which constitutes an actual
capillary boiler inside of which the water squeezed in between its
walls cannot assume its spheroidal state, and the formation of drops
becomes absolutely impossible. There exists no longer a residue of hot
water, nor are water gauges, safety valves, or any other of those
numerous accessories required which make all steam boilers so
complicated and which augment considerably their cost.
It also becomes unnecessary to connect the joint from which the steam
escapes by means of a valve with the motor for which the steam is to
be used. If the supply of steam is to be stopped, this can be done by
simply suppressing the supply of water, i.e., by _emptying the
boiler_.
The regular working is assured by the quantity of heat contained in
the heated iron tube, to which, for this purpose, an intentionally
great thickness has been given, and it is this heat of the iron which
replaces the heat furnished by the hot water in the steam generators
with boiler tubes. From the above it will be easy to understand the
general arrangement of the new steam generator, when connected with
its motor. This motor works a small intermitting pump, which supplies
the capillary boiler with water, according to the quantity consumed.
The machine is started by means of a small special pump worked by
hand.
Whenever the velocity of the motor tends to increase, a centrifugal
regulator placed upon the motor reduces the action of the pump and,
consequently, the supply of water to the tube, thus checking the
velocity of the machine. If the velocity tends to slacken, the inverse
process is employed. In order to stop the machine, it suffices to turn
off the water furnished by the pump by means of a three-way cock, and
to send the water back to the reservoir of supply. The boiler can be
emptied in less than a second, and the motor stops in consequence of
being deprived of motive power.
The whole is marvelously simple, and creates astonishment and
admiration in the mind of even the most skeptical persons who see the
apparatus.
The boiler of the one horse power type weighs 33 kilogrammes. It
consists of an iron tube having a length of 2 meters and a height of
10.5 centimeters after it has been flattened; the total heating
surface thus obtained being 48 square centimeters. The power of
vaporization amounts to 20 kilogrammes of water per hour, while the
quantity of coal consumed during the same period amounts to only 4
kilogrammes, which is comparatively little for a boiler of so small a
power.
[Illustration: FIG. 2.--TRICYCLE PROPELLED BY A SERPOLLET BOILER]
Fig. 2 shows the first model of a tricycle constructed by Messrs.
Serpollet as an application of their boiler for locomotion. The writer
has seen the working of this apparatus, and consequently is able to
give some data. The total weight of the machine is 185 kilogrammes, or
about 250 kilogrammes when mounted by a person. The boiler is placed
behind the tricycle, the motor is under the seat, inside of which is
the water reservoir and the supply of coal. In the motor employed in
the present case the feed pump is a constant supply pump, but by means
of a directing lever turning around its own axis and acting upon a
three-way cock, the water can be divided into two streams, the one
emptying into the feeding reservoir, the other into the boiler. By
varying the position of the cock, the power of the machine can be
modified and its velocity regulated. The machine can be brought to a
stop within less than two meters by means of the combined action of a
brake and the complete suppression of water in the boiler. In order to
start the machine, the water is sent into the tube by a little extra
pump worked for a moment by the left hand of the cyclist when
starting.
On July 25 some experiments were made before the Society of Civil
Engineers with the tricycle above described, and on that occasion it
traversed the Rue Girardon and the Rue de Norvino to Montmartre
(streets in which the gradient rises to 15 centimeters per meter) with
a velocity of three meters per second.
Fig. 3 represents the arrangement of the first stationary boiler of
the new kind. The letters of reference will suffice to indicate the
position of the principal parts of it, the forms of which may be
varied according to the object for which the boiler is to be used.
[Illustration: FIG. 3.--COMPLETE VIEW OF A SERPOLLET BOILER.
1. Exterior view. 2. Cross section. 3. Horizontal section at the
height of the tube.]
Messrs. Serpollet are occupied at present with studying the special
arrangements which will be needed for connecting their boiler with a
quadricycle, a torpedo boat, a stove, a locomotive, or a stationary
machine of 10 horse power, and with rectangular parts.
The inexplosibility of their boiler has been tested during an
experiment made before the engineers of mines, on which occasion a
manometer (steam gauge) graduated for a pressure of upward 200
kilogrammes per square centimeter was used, and the pressure raised
far beyond the limits indicated. The result was that the hand of the
manometer, being pressed against the walls of the box, became bent,
and though the boiler was submitted to a pressure the degree of which
it was impossible to measure, it was not changed in the slightest.
Incrustation of the boiler is not to be feared, for, in consequence of
the great velocity with which the steam circulates through the tube,
the solid matter dissolved in the water becomes pulverized and is
forced out, mechanically assisting to lubricate and polish the parts
of the motor.
The invention of Messrs. Serpollet is still too new to foretell all
its possible applications, but their apparatus, in its present form,
is exactly the steam generator which will be useful for producing a
small motive force; while it will be necessary to wait until it has
been ascertained, by further study, how the system can economically be
used for high motive power.
The most natural and immediate application of the invention seems to
be its use for the electric lighting of restaurants, in which case one
of the instantaneous vaporization tubes might be connected with stoves
which remain lighted all day, and which might thus besides supply the
necessary motive force to work a small dynamo charging some
accumulators.--_E. Hospitalier, in La Nature._
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