AN IMPROVED SYSTEM OF SUPPLYING AIR TO COAL AND MINES, AND APPARATUS USED THEREWITH." OTHER
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by John Sturgeon at the Office of the
Commissioners of Patents on the 20th November 1877.
JOHN STURGEON, of Crosby, near Liverpool, in the County of Lancaster,
Engineer. "AN IMPROVED SYSTEM OF SUPPLYING AIR TO COAL AND
MINES, AND APPARATUS USED THEREWITH."
OTHER
Heretofore it has been the practice to ventilate coal mines by means of a current
of air drawn through the various roads and working places, which current is
produced by drawing or sucking up the air through one shaft while it descends
through another, the air being directed through the various working places of the
mine by means of air ways, bratticing, stoppings, and other contrivances on its way
from the down-cast to the up-cast shaft. This system has, however, this dis-
advantage that the vacuum produced by the draft up the up-cast shaft has as much
tendency to liberate and draw into the mine the gases from the coal, as to draw in
the outside pure air, and must, in fact, act first upon the internal gases, which are
nearest to it. A much greater quantity of air is thereby rendered requisite to
dilute the gases drawn in sufficiently to render them harmless; and the condition of
the mine as regards ventilation is so delicately balanced as to be often dangerously
affected by even slight atmospheric changes.
According to my Invention, instead of sucking air through the mine, I propose to
force it into and through the workings under pressure, the compressed air being
conveyed direct to the furthest end of the mine and the working places, from
whence it is allowed to find its way back to the outlet shaft in the most convenient
way. For this purpose I propose to close up the entrance to the mine at the
bottom of the shaft by a system of air-tight chambers or "air locks" (herein-after
described), all other outlets through which air might pass out being also closed up
and made as far as possible air-tight. Pipes laid along the roads and other places
wherever convenient through the mine are supplied with compressed air from
suitable air compressing or forcing machinery at the top, these pipes being provided
with nose couplings, valves &c., to enable the compressed air to be let out into any
part of the mine, wherever required, until it attains the desired pressure in the
mine, so as to hold back as much as possible the gases from entering, and at the
[Price 2d1

page_text: same time supply the necessary volume of new air as the old air becomes vitiated
and is passed out.
The object of the air locks above referred to is to allow of ingress to and egress
from the mine both for the coal wagons and the miners in passing to and from the
shaft, without allowing the air to escape too rapidly. These locks consist of air-
tight chambers, provided with air-tight doors on the inside towards the mine,
and on the outside towards the shaft, these doors being so arranged that the one
cannot be opened until the other is shut. I propose to provide separate air locks
for the full and for the empty wagons, of sufficient size to contain the number of
The
wagons taken at each lift of the cage; and also separate locks for the men.
wagons can be shunted through these locks by opening one door, passing them in,
then closing the door after them, and then opening the other door, the men passing
through their locks by a similar process.
In order to avoid inconvenience from the sudden blast of air that would issue
from the locks in opening the doors I apply valves to enable the pressure to be
let off gradually before opening the doors.
In the case of the locks used for the passage of the men I apply such valves for
the admission of air from the mine into the lock as well as for its discharge there-
from. A large safety valve arrangement should also be provided, to take effect in
case of any sudden or unusual pressure against the locks caused by an explosion or
otherwise.
The ordinary working of these locks will create a constant creeping movement of
the air from the further end of the workings towards the mouth of the mine, and this
movement of the air can be increased to any required extent by means of regulating
sluice valves, or balanced valves arranged to open antomatically under a given or
set pressure.
Instead of placing the air locks at the entrance to the mine, they may be placed
at any convenient part of the workings further into the mine. Or it might be
found convenient to work only a portion of the mine under pressure, or one portion
under a higher pressure than another, as, for instance, when a higher pressure is
required to keep back or regulate an influx of water; in all these cases the air
locks already described may be employed.
Instead of the air locks, the top of the shaft might be covered in with an enclosed
chamber, so arranged as to admit the cage, and provided with doors to close the
shaft while moving wagons to or from the cage, a small opening being left through
this chamber for the rope to pass through. By these means air can be conveyed
throughout and to any part of the workings at such pressures and in such pro-
portions as may be required, without the necessity of special air shafts, air roads,
bratticing, stoppings, and other complicated workings, at much less cost and with
much greater safety to the mine than by the present system. Air can be conveyed
to headings and working places by service pipes from the principal air main, and
hose pipes may be coupled up, which can be directed by hand to any particular spot,
to blow away gas or the smoke from a shot; and in case of an explosion or other
accident, the air can still be supplied to the mine as before. In the case of a fire,
water can be passed down through the air pipes and directed against the place on
fire, thereby avoiding the necessity of drowning the whole mine, except in extremo
One great advantage of my system is that by maintaining a pressure of air
in the mine the inflow of water will be in many cases prevented, and in all cases
greatly reduced, thereby effecting a considerable saving in the cost of pumping.
cases.