IMPROVEMENTS IN AIR COMPRESSORS
Year: 1880

page_text: LETTERS PATENT to William Lloyd Wise, of 7, Whitehall Place, in the City of
Westminster, for an Invention of "IMPROVEMENTS IN AIR COMPRESSORS."
"
A communication from abroad by Charles William Burton, of Paris, in the
Republic of France.
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 8th May 1880).
WILLIAM LLOYD WISE, of 7, Whitehall Place, in the City of Westminster.
"IMPROVEMENTS IN AIR COMPRESSORS." (A communication from abroad by
Charles William Burton, of Paris, in the Republic of France.)
This Invention consists in the application to air-compressors of cylindrical
pistons practically balanced, and worked automatically by means of compressed air
by the compressor itself.
These pistons replace with advantage ordinary valves which strike upon their
seats, thus suppressing the disadvantages of burring up of the metal, noise, frequent
repairs, &c.
The admission and exhaust of the air are effected by the action of the compressor
piston acting on small pistons, which effect the admission and exhaust by means of
the compressed air, with which the passages are in communication at the end of
the stroke of the main piston so as to act in the direction required on the small
pistons or distributors.
The two distributors which admit the air into the cylinder are connected together,
both being arranged to work exactly to the end of the stroke of the main com-
pressing piston.
The two distributors which exhaust the air, that is to say, which allow it to
escape when it has attained the desired pressure, act on the contrary separately.
They both remain in their places ready to move when the time comes for each one
to do so. Each of these small pistons works in a cylindrical case of two different
diameters, and terminating in two faces, one of which is rather larger than the
other. The object of this arrangement is to practically balance the distributor by
overcoming the resistance due to friction owing to the excess of pressure on the
larger area, both surfaces being in communication with air at the same pressure.
Panice 21

page_text: When the compressor piston has compressed the air previously admitted into the
cylinder to a degree slightly higher than the pressure in the reservoir of compressed
air, this air acts on the corresponding distributor piston, which yields and gives it
passage.
The compressor piston continues its stroke, and at the moment it reaches the end
of this stroke, by means of a passage which affords communication between the
compressing face of the piston and the admission distributor, the small quantity of
compressed air remaining in the dead spaces, or in a recess formed in the piston
rod pushes the distributor, which changes its position and closes the admission
orifice on the opposite side, and opening this same orifice at the side where the
piston begins its backward return stroke.
The air which has thus acted on the distributor at the same time expanding is
then exhausted into the atmosphere by a passage recessed in the rod, and at the
moment the piston reaches the opposite end of its stroke. The rod passes through
both covers.
Instead of making use of passages and orifices coming into juxta-position at
the ends of the stroke for allowing a passage for the compressed air on to the
distributing admission piston, I also employ a small valve fitted to each cover, pro-
jecting to the extent of scarcely. 1 or 2 millimetres, inside the cylinder and struck
and opened by the face of the compressing piston at the end of its stroke. At this
moment the compressed air acts on the admission piston, and immediately the
piston begins its return stroke the small valve provided with a spring closes, and
opens on the opposite side to the atmosphere. a passage for the air which has acted
on the distributor.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Lloyd Wise in the Great Seal Patent Office on the 8th
November 1880.
WILLIAM LLOYD WISE, of 7, Whitehall Place, in the City of Westminster.
« IMPROVEMENTS IN AIR COMPRESSORS." (A communication from abroad by
Charles William Burton, of Paris, in the Republic of France.)
These improvements relate chiefly to the application of balanced pistons
(operating as valves) to air compressors.
These pistons, which are sensibly balanced, are automatically actuated by com-
pressed air from the compressor itself, whose piston, in connection with suitable
passages and moving ports, regulates the admission of atmospheric air into the
cylinder and the emission of the compressed air into the reservoir provided for that
purpose.
By the application of piston valves or cylindrical slides according to this
Invention valves of the kind ordinarily used are entirely dispensed with.
And in order to a clear understanding of the Invention I now proceed to describe
it in detail with reference to the accompanying Drawings, whereof Fig. 1 represents
a sectional elevation of the compressor cylinder in the line D, E.
Fig. 2 represents a sectional plan of the cylinder through the two lines forming
the angle A, B, C.
The apparatus consists of a cast iron cylinder a provided with a tank to contain
water for maintaining the compressed air at its normal temperature; the cylinder
is double acting, and contains the piston m mounted on the rod b. On the sides of
the large cylinder two small cylinders c and d are placed. In the cylinder c two
pistons and connected together by a rod regulate the admission of atmospheric
air into the compressor cylinder through the openings g, gl, the passages h, h',
serving for the introduction of the air into the small cylinder c. The cylinder d, d',
encloses two pistons e, e¹, which however work separately; these pistons are for
the purpose of opening or closing the communication through the ports p, p, and
the passage between the compressor cylinder and the compressed air receiver.
Two methods of working the pistons f. f', are illustrated in Fig. 2, that about to be
first described being shewn at the left band of the Drawing. The rod 6 of the
large compressor piston works in two stuffing boxes k, l, of long bore provided
with three rings of brass (or of any suitable material) dividing each stuffing box
into two parts. On the middle ring is a channel i to form a passage for the com-
pressed air from the large cylinder to the two ends of the small cylinder c.
The two
longitudinal cavities j, j and the transverse holes o, o¹, made in the compressor
piston rod enable the two ends of the small cylinder c to communicate with the
large compressor cylinder when the piston of this latter has arrived at the end of
its stroke. The compressed air that remains in the ends of the cylinder c after the
stroke of the pistons is completed escapes through the compressor piston rod by
means of the passages, ol, in this rod when they come in communication with
the pipe i.
The apparatus operates as follows:-
Supposing the travel of the compressor piston to be in the direction of the arrow
indicated in the plan, atmospheric air enters the small cylinder through the
passage h¹, turns round the piston f¹, and passes into the large cylinder through
the openings g; the air enclosed on the other side of the piston is at the same
time being compressed, and when it has exceeded the pressure of the air contained
within the receiver by a sufficient amount (dependent on the friction and the
difference of areas of the two ends of the small piston e) acts on the surface of the
piston e, and causes it to make its stroke, thereby opening the communication
between the compressor cylinder and the receiver.
As soon as the compressor piston has arrived at the end of its stroke and begins

page_text: to open the admission port the compressed air enclosed within the receiver presses
in its turn on the opposite surface of the piston c and forces this latter to return
and occupy its former position, that is to say, to close the communication between
the compressor and the receiver. It is well to remark that the piston on which
the air contained in the receiver acts is of less diameter than that of the opposite
piston attached to it, also actuated by the air in the receiver, in order to obtain the
difference of pressure necessary for the working of this piston.
During the stroke of the compressor piston m the space J in the rod b becomes
filled with compressed air, and as soon as the piston m has arrived at the end of its
stroke this air passes by the pipe i to the piston fand forces the two pistons f, f¹,
together towards the other end of the cylinder c, thus stopping the admission of
atmospheric air into the compressor cylinder through the port g¹ and opening the
communication g placed at the other end of the cylinder.
The small passages r, r, in the compressor piston serve to communicate from the
clearance space the necessary compressed air for working the pistons ƒ, ƒ¹, in case
the air chambers j, j¹, in the piston rod b had not volume and pressure sufficient to
work the piston ff.
All the pistons working in the cylinders c, d, d¹, are provided at each end with
steel or iron projections, which strike on india rubber plugs designed to deaden the
shock resulting from the great speed of these pistons.
The Invention further relates to another system that may be applied to the
working of the pistons f, f¹, and which does not necessitate the employment of the
holes j,,, made in the compressor piston rod b.
It consists of a valve q placed on the cover of the compressor cylinder a. This
valve projects about 2 millimetres into the interior of the cylinder, and is opened
by the compressor piston when it arrives at the end of its stroke to allow of tho
passage of a certain quantity of compressed air to operate the pistons f, f¹. A
spiral spring placed over the valve causes it to close when the compressor piston
draws away.
A screw is fixed above the valve spindle to regulate the height of its lift. This
screw is provided with a central hole to permit the evacuation of the compressed
air that remains at the ends of the cylinder c after each stroke of the pistons f, f
Having described the nature of the said Invention, and explained in what
manner the same is to be or may be performed or carried into practical effect, as
communicated to me as aforesaid, I would have it understood that what I claim as
new and secured to me under the Letters Patent hereinbefore in part recited
is,―
1. In air compressors regulating the admission of air to be compressed and the
emission of compressed air from the cylinder by means of piston valves or
cylindrical slides operated by air compressed by the compressor, substantially as
described, and specially the mode of conveying the said compressed air in the
piston rod itself.
2. The piston and rod with compressed air or other motive power fluid chambers
for driving the inlet piston valves, and the system of ports in the piston rod which
communicate the said power fluid to the piston valves at the exact moment
required through tubes or any other passage, and also similar ports which open the
small cylinders to the exhaust, substantially as described.
.
In witness whereof, I, the said William Lloyd Wise, have hereunto set my
hand and seal, this Eighth day of November, in the year of our Lord One
thousand eight hundred and eighty.
W. LLOYD WISE. (L.S.)