IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR FOR USE AS A MOTIVE FOR DRIVING ROCK BORING MACHINERY, PUMPS, LIFTS, AND OTHER MACHINERY WHERE STEAM POWER IS INAPPLICABLE, AND ALSO AS A PERFECT VENTILATOR OF ALL KINDS OF MINES AND UNDERGROUND WORKINGS."
Year: 1877

page_text: LETTERS PATENT to John Edwards Stokes, of Eastcott Villa, Selwyn Road,
Upton Manor, in the County of Essex, for the Invention of "IMPROVEMENTS
IN MACHINERY FOR COMPRESSING AIR FOR USE AS A MOTIVE FOR DRIVING
ROCK BORING MACHINERY, PUMPS, LIFTS, AND OTHER MACHINERY WHERE
STEAM POWER IS INAPPLICABLE, AND ALSO AS A PERFECT VENTILATOR OF ALL
KINDS OF MINES AND UNDERGROUND WORKINGS."
PROVISIONAL SPECIFICATION left by the said John Edwards Stokes at the
Office of the Commissioners of Patents on the 25th September 1877.
JOHN EDWARDS STOKES, of Eastcott Villa, Selwyn Road, Upton Manor, in the
County of Essex. "IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR FOR USE
AS A MOTIVE FOR DRIVING ROCK BORING MACHINERY, PUMPS, LIFTS, AND OTHER
MACHINERY WHERE STEAM POWER IS INAPPLICABLE, AND ALSO AS A PERFECT
VENTILATOR OF ALL KINDS OF MINES AND UNDERGROUND WORKINGS."
The principle of this Invention consists of a series of inlet valves and cylinders
fitted into the outside covers of a main cylinder, such number of valves and small
cylinders to be determined by the size of the main cylinder, each valve to have a
free and independent action of itself, and perfectly free from all kinds of springs as
now used in other air compressors. The small cylinders have centre guides for the
valves, and are firmly screwed into the outside covers of the main cylinder. These
inlet valves are set in a horizontal position, and the instant the piston in the main
cylinder commences to move forward the valves are then in operation, and on the
return of the piston they are instantly closed and the valves at the opposite end of
the main cylinder are opened to admit the air. The outlet or receiving valves are
also fitted into small cylinders in a vertical position on the top of main cylinder,
and are adjustable by means of set screws, and as in the case of the inlet valves the
number of these outlet or receiving valves to be determined by the size of the main
cylinder; and around the air cylinder is a receptacle for a supply of water to prevent
the cylinder generating heat when at work.

page_text: I claim for my Invention the construction of the air valves and small cylinders in
which they work or move, and are set in motion only by the vacuum formed by the
momentum of the piston in the main cylinder.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Edwards Stokes in the Great Seal Patent Office on the 22nd
March 1878.
JOHN EDWARDS STOKES, of Eastcott Villa, Selwyn Road, Upton Manor, in the
County of Essex. "IMPROVEMENTS IN MACHINERY FOR COMPRESSING AIR AS
A MOTIVE POWER FOR DRIVING ROCK BORING MACHINERY, PUMPS, LIFTS, AND
OTHER MACHINERY WHERE STEAM POWER IS INAPPLICABLE, AND ALSO AS A PERFECT
VENTILATOR OF ALL KINDS OF MINES AND UNDERGROUND WORKINGS."
The Invention relates to self-acting automatic valves and cylinders for compressing
air as a motive power to work and drive rock drills, pumps, lifts, all kinds of
stationary engines, locomotives, tram cars, and for propelling ships.
These improvements consist of a new arrangement and form of the inlet valves,
the construction and operation of the valve motion, and in the outlet valve device,
which regulates the delivery of air from the air cylinder into the receiving chest, the
number of the inlet and outlet valves being regulated by the size of the air cylinder,
also a new and peculiar design and construction of the air cylinder.
The air is compressed by means of a piston working reciprocally in a cylinder,
and by means of the valves to be hereafter described. The air is admitted into the
interior of the cylinder during the retreat of the piston from either end, and on the
piston returning the inlet valves close, the air is compressed and forced through
outlet valves into a cast-iron receiver, from whence it passes through pipes to the
desired work.
The inlet valves are of a cylindrical shape, being small casings of metal with wings
inside, which connect the casings with the central guides and seatings at the back.
Between these seatings and the casings recesses are turned, leaving a space between
the wings and casings free for the passage of the incoming air, which passes through
the said recesses into the cylinder, when the valves are drawn from their seatings by
the suction of the receding piston.
The valves have central steel spindles, with lock nuts to adjust their traverse
and to prevent their falling into the cylinder, as also leather washers between the
nuts and bridge of casings (to be hereafter described) to break the shock of their
sudden opening.
The casing in which each of these valves works is recessed at back to form a
seating for the valve, which is accurately fitted into it, and the casing has flanges on
its outside and is itself fitted into the outside end cover of the main cylinder, which
is bored for that purpose, and is held in its place by the said flanges being screwed
on to the main cover. Thus the valve seats are inside the cylinder, and the valves
open inwards. By this arrangement all springs and other appliances are dispensed
with, and the action of the valves is automatic, they being actuated by the suction
caused by the motion of the piston inside the cylinder.
The air on being compressed finds an outlet through slots in the ends of the
cylinder to the outlet valves, which are seated on flanged bushes screwed to recesses
or boxes cast on the top of the cylinder.

page_text: Each outlet valve is circular in form, slightly coned at the base to form a seating,
and with four wings below the seating. These wings are fitted into the bush and
form a bottom guide. Above, each valve is produced into a stalk, which works
vertically in a central guide screwed firmly down on the top of the flanged bush
already described. The lift of these valves is regulated in each case by an adjust-
able set screw and lock nut screwed through an outside cover, which admits of access
to each of the outlet valves, guides, and bushes.
After the air has passed the valves it goes through the air passage, which leads
down the side of the air cylinder into the receiver, on which the cylinder is bolted.
An oil syphon is fitted on to the centre of the cylinder to lubricate the piston during
its motion. Round the cylinder and up to a point above the covers of the outlet
valve boxes a water casing is formed, through which a constant stream of cold water
is kept running to prevent any expansion.
The piston is a cylindrical block fitted with three steel spring rings to prevent the
escape of air. The piston rod is produced through both ends of the cylinder through
glands and stuffing boxes on the outside covers, and the front end is coupled to a
cross-head working in guide bars with a connecting rod and brasses, which join it
to a crank. This crank is worked round by two steam cylinders, placed one on
each side of the air cylinder, with cross head, slide bar, and connecting rod to each.
These connecting rods are joined to two crank pins (which are produced to form
eccentric throws to work the slide valves) which crank pins are keyed into two disc
fly wheels, which are also keyed on to the crank shaft by which the air piston is
worked.
The air and steam cylinders are bolted on one end of the air tank or receiver,
which may be of cast iron cast in one piece. The crank shaft carrying the disc fly
wheels and connecting rods are supported in bearings on arms or brackets cast on
the other end of the air tank or receiver.
And in order that my said Invention may be more fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of my Drawings represents a side elevation of the machine, showing
position of the outlet valves.
Figure 2 is a plan view, showing the general arrangement of the machinery.
Figure 3 is an end view, showing the position of the inlet valves.
Figure 4 is a sectional elevation of outlet valve, with top covers and screws.
Figure 5 is a plan of outlet valve.
Figure 6 is a sectional elevation of inlet valve.
Figure 7 is a plan of inlet valve.
In the plan view at Figure 2, and also the end elevation at Figure 3, G is the
air compressing cylinder, having the piston R inside at half stroke, and the two end
covers (see also Figure 1) F, F, at either end, in which are fixed the flanged bushes
E, E, E, containing the inlet valves B. The piston rod S is brought through glands
T, T, and the front end cottared to a cross head U, sliding in guide bars V, V.
The connecting rod W joins the cross head to the crank ✗
keyed to the disc fly wheels a, a, in which the crank pins f. f. (forming also the
eccentric throws for the slide valve rods h, h,) are also keyed.
This crank X is
The two steam cylinders Y, Y, drive the crank shaft round in the ordinary
manner of steam engines by the connecting rods b, b.
The air after passing through the outlet valves H, H, (which are guided by the
wings L (see also Figure 4) at bottom, and stalks working vertically at flanged
guides K) passes inside the flanged bush J, through the passage P, into the hollow
tank or receiver Z, on which the air and steam cylinders are bolted. The lift of the
outlet valves is regulated by the set screw O, screwed through the covers N, N, on
the top.
To the side of the air tank or receiver is screwed a pressure indicator, as shown

page_text: at p, and a relief valve r, with spring balance n, also a valve y, to supply the air
to the work requiring it.
In the sectional elevation shown at Figure 6, and also plan view, Figure 7, B
is the valve proper, with wings and seatings; E is the flanged bush in which it
works; C, the steel spindle to adjust its motion; and D, the lock nuts.
Having now described and particularly ascertained the nature of my said
Invention, and the manner the same is or may be carried into effect, I would
observe in conclusion that what I consider novel and original, and therefore claim
as the Invention secured to ine by the herein-before in part recited Letters Patent,
is,―
First. The design and combination of the inlet valves, valve seats, and cylindrical
casings, with their central guides and set nuts, as arranged at opposite ends in the
covers of the air cylinder, substantially as and] for the purpose herein-before
described.
Second. The design and combination of the outlet valves, their cylindrical flanged
bushes, stalks, and winged guides, as arranged and fixed in recessed boxes on the
top of the air cylinder, substantially as and for the purpose herein-before
described.
Third. The design and combination of air cylinder with seatings, air passage,
and water tank, cast in one piece, affording a direct passage for the air to the
receiver, with only one joint, substantially as and for the purpose herein-before
described.
In witness whereof, I, the said John Edwards Stokes, have to this my
Specification set my hand and seal, this Twentieth day of March, One
thousand eight hundred and seventy-eight.
JOHN EDWARDS STOKES. (L.S.)