IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR."
Year: 1876

page_text: LETTERS PATENT to Edmund Maden, of Portland, in the County of Dorset,
for the Invention of "IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR."
PROVISIONAL SPECIFICATION left by the said Edmund Maden at the Office
of the Commissioners of Patents on the 1st April 1876.
EDMUND MADEN, of Portland, in the County of Dorset.
MACHINERY FOR COMPRESSING AIR.
"IMPROVEMENTS IN
The improvements consist in the application of the attractive force of electro-
magnets for the purposes of actuating improved machinery for compressing air;
also in the arrangement of the electro-magnet machinery, and in the construction
and disposition of the machinery for compressing and storing air.
The improvements may be performed by constructing a series of cylindrical
chambers of metal with convenient flanges thereon for firmly securing them together,
and passing through the walls of the said chambers and from end to end of the
series thereof two accurately fitted piston rods furnished with a piston fitted in each
chamber, the pistons being so constructed that their travelling space in each chamber
shall not exceed one-sixteenth of an inch. In each chamber one or more orifices or
valves for the reception and expulsion of air are constructed. The arrangement of
the electro-magnets may be in pairs, a pair at each end of the series of air chambers
or compressor, in such manner that the north pole of one magnet will attract the
south pole of the other. One of said pairs is firmly fixed to each end of the com-
pressor, and the other on frames so mounted that they may travel backwards and
forwards;
these travelling electro-magnets are attached to the piston rods of the
compressor, which project at each end. For passing the compressed air into a
storing chamber or accumulator I construct any convenient eccentric and slide valve
arrangement, and actuate it by the machinery put in motion by the compressed air,
which machinery may also work the parts for passing the current to and from the
electro-magnets. The apparatus for generating force in the electro-magnets may
be of any suitable kind, but prefer to use Wilde's or the Graının Company's
machines.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Edmund Maden in the Great Seal Patent Office on the 27th September
1876.
EDMUND MADEN, of Portland, in the County of Dorset.
MACHINERY FOR COMPRESSING AIR."
"IMPROVEMENTS IN
The improvements consist in the application of the attractive force of electro-
magnets for the purposes of actuating improved machinery for compressing air;
also in the arrangement of the electro-magnet machinery, and in the construction
and disposition of the machinery for compressing and storing air.
The improvements may be performed by constructing a series of cylindrical
chambers of metal with convenient flanges thereon for firmly securing them together
and passing through the walls of the said chambers and from end to end of the
series thereof two accurately fitted piston rods furnished with a piston fitted in each
chamber, the pistons being so constructed that their travelling space in each chamber
shall not exceed one-sixteenth of an inch; in cach chamber one or more orifices or
valves for the reception and expulsion of air are constructed. The arrangement of
the electro-magnets may be in pairs, a pair at each end of the series of air chambers
or compressor, and in such manner that the north pole of one magnet will attract
the south pole of the other. One of said pairs is firmly fixed to each end of the
compressor, and the other on frames, so mounted that they may travel backwards
and forwards; the travelling electro-magnets are attached to the piston rods of
the compressor, which projects at each end. For passing the compressed air into a
storing chamber or accumulator I construct any convenient eccentric and slide valve
arrangement, and actuate it by the machinery put in motion by the compressed air,
which machinery may also work the parts for passing the current to and from the
electro-magnets. The apparatus for generating force in the electro-magnets may
be of any suitable kind, but I prefer to use Wilde's or the Gramm Company's
machines.
Fig. 1 is a general plan of the apparatus, and Figs. 2, 3, and 4 details thereof.
One or more cylindrical air chambers c¹, c, c, are constructed with flanges, and each
fitted with a piston, which is made to work perfectly air-tight. The travelling
space of each piston in the air cylinders does not exceed one-sixteenth of an inch.
At each end of the cylinders or series of cylinders a pair of electro-magnets M, M, is
placed, one of each pair being firmly bolted to the end of the system at a, a, and
the other firmly fixed to cross-heads b, b, joining the ends of two piston rods p, p,
which pass through the covers and partitions of the air cylinders, and the pistons
being attached to the rods move simultaneously. The electro-magnets ML, M, are
so fixed to the piston rods that when the poles of one pair are in contact, as at NP,
the poles of the other pair are one-sixteenth of an inch apart, as at Sr. But the
electro-magnets of each pair are so fixed in relation to the pistons that they are
prevented from coming into actual contact, and they are so placed that the north
pole of one will be opposite to the south pole of the other. On one side of each
cylinder two small ports are made for admitting the air, and on the other side two
similar ports are made for expelling the air from the cylinders into a receiver or
holder H, L. The air is admitted to each side of the pistons alternately by means
of a slide valve V worked from the shaft s by means of the arrangement X, and is
passed to the holder by means of automatic spring valves V, V, which prevent the
return of the air into the cylinders after its expulsion by the pistons.
Fig. 3 shows the slide valve arrangement, in which V, V, V, V, V³, Vs, are the
valves; and Fig. 4 shows the automatic spring valve arrangement. The electro-
magnets M, M, are rendered magnetic by means of a current generated by a
magneto-electric machine B. To bring the compressor into action the handle of the
magneto-electric machine H is turned, and thus a current is generated, which
passing through the coils of the electro-magnets M, M, renders thein magnetic. With
the magneto-electric machine B or current generator a shaft (s) is connected, which
is made to revolve at the same time that the current is being generated. On this

page_text: snait a wheel of wood Y (detailed in Fig. 2) is fixed, having on it a ledge on which
a ring of copper is placed. An insulated copper wire conveys the current from
the positive pole A of the magneto-electric machine to this ring, and then a small
strip of copper g conveys it to a segmental strip of copper , which is fastened to
the outside periphery of the wheel. One end of the wire of one pair of electro-
magnets is made to press against one side of this wheel a i, and the end of the
wire of the other pair is made to press against the opposite at j. The other
end of the wire of each pair of electro-magnets is connected with the negative
pole (c) of the magneto-electric machine or current generator B. At cach revolution
of the wheel the current will be made to pass through the coils of each pair of
electro-magnets alternately, and as each pair becomes magnetic a movement of the
pistons p, p, is produced, which will force the air from the cylinders c¹, c², c³, into
the holder H, L. A tappet X¹, Fig. 3, is fixed on the same shaft (8) and made to
revolve within a hollow square X, which by a rod R is connected with the slide
valve V, by which air is admitted into the cylinders. This square X, Fig. 3, is
made eccentric with the shaft 8 on which the tappet X¹ is fixed. The tappet X' is
made to strike the side of the square X when the wheel is in that part of its revolu-
tion at which the current is cut off from both pairs of electro-magnets. In this way
a communication is opened between the air cylinders and the atmosphere on that
side of the pistons from which the air has been expelled; and the communication
with the atmosphere is closed on that side from which the air will be expelled at
the next stroke of the pistons. By turning the handle H of the magneto-electric
machine B a pressure of air can be obtained in the holder H, L, equal to the
attractive power of the electro-magnets M, M. The air compressed in this way can
be used for various purposes, amongst others it can be employed as a motive-power
instead of steam. For this purpose a machine A, E, similar to a steam engine is
constructed, which the compressed air is intended to work in the same way as steam
would do. By an endless band K this air motor is connected with the shaft (8), on
which the before-mentioned wheel Y and tappet X are fixed, and which, in the first
place, is worked from the handle H of the magneto-electric machine B, but when a
sufficient pressure of air has been obtained, the connecting band F is removed from
the handle of the magneto-electric machine. By opening a valve communicating
with the holder H, L, the air engine A, E, is started, and the endless band K on the
wheel L is passed from a loose pulley to a fast pulley 1, and the shaft s on which
the wheel Y and tappet X are fixed will thus be operated upon by the air
engine A, E, instead of by hand. The diameter of the air cylinders c¹, c², c³, of the
compressor must be made proportionate with the diameter of the cylinder and length
of stroke of the air engine A, E, and then by multiplying gear the action of the air
compressor when connected with the air engine can be made to force as much air
into the holder as will be exhausted at each stroke of the air engine, and thus a
constant supply at an equal pressure may be maintained in the holder H, L. The
force of the machine will of course depend on the amount of attractive power which
can be developed in the electro-magnets. From experiments it has been found that
a pair of electro-magnets sixteen inches long having a core four inches diameter,
wrapped with No. 12 insulated copper wire, and connected with a magneto-electric
machine giving a current equal to a battery of four bichromate cells (Russell's
No. 6), will lift 25,600 pounds through a distance of one-sixteenth of an inch.
making the shaft S (on which the wheel Y is fixed which distributes the current to
the two pairs of electro-magnets M, M, alternately) to revolve eight times in a
second sixteen movements of the piston are produced, which is equal to lifting
25,600 pounds through one inch in a second, or 25,600 pounds through sixty inches
or five feet in one minute. But 25,600 pounds lifted through five feet in one
minute is equal to five times 25,600 or 138,000 pounds through one foot in one
minute. This divided by 32,000, Watt's standard of one-borse power, gives four
horse power as the amount of mechanical force which can be made available by this
machine when two pairs of electro-magnets of the above dimensions are used in
connection with a magucto-electric machine of the above mentioned power. Since
By

page_text: the attractive force of electro-magnets increases as the square of the diameter of the
core multiplied into the square of the strength of the current, it is evident that
machines of great power can be produced in this manner.
In witness whereof, I, the said Edmund Maden, have hereunto set my hand
and seal, this Twenty-second day of September, in the year of our Lord
One thousand eight hundred and seventy-six.
TOMIIND MADEN
(IS)
EDMUND MADEN
(IS)