IMPROVEMENTS IN APPARATUS FOR EXHAUSTING OR FORCING AIR FOR VENTILATING COAL AND OTHER MINES, AND FOR OTHER PURPOSES
Year: 1879

page_text: LETTERS PATENT to John Nixon, of No. 117, Westbourne Terrace, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
EXHAUSTING OR FORCING AIR FOR VENTILATING COAL AND OTHER MINES, AND
FOR OTHER PURPOSES."
Sealed the 19th September 1879, and dated the 1st April 1879.
"
PROVISIONAL SPECIFICATION left by the said John Nixon at the Office
of the Commissioners of Patents on the 1st April 1879.
JOHN NIXON, of No. 117, Westbourne Terrace, in the County of Middlesex.
IMPROVEMENTS IN APPARATUS FOR EXHAUSTING OR FORCING AIR FOR VENTILATING
COAL AND OTHER MINES, AND FOR OTHER PURPOSES."
In the Specification of a former Patent granted to me on the 15 November 1861,
No. 2875, I described an arrangement of apparatus for withdrawing air from coal
or other mines. In this arrangement of apparatus a pair of rectilinear pistons
were used working to and fro in correspondingly formed air chambers. The pistons
had motion given to them by two cranks at right angles to one another on the
crank shaft of an engine.
With this apparatus the withdrawal of the air was irregular, and was not
uniform throughout the stroke or movement of the pistons, the consequence was
that pulsatory oscillations were set up in the air throughout all the workings and
passages in the mine.
To remedy this defect I now form the apparatus with three air chambers, each
having in it a piston, and give motion to the pistons from three cranks equally
spaced around a cranked driving shaft; and in order to improve the construction
of the apparatus and to obtain a more steady and uniform movement of the pistons
I form the apparatus in the following manner:-
I give motion from a steam engine to a horizontal shaft, on which are three
cranks set at equal angles around the shaft. From the three cranks motion is
transmitted by connecting rods to the piston rods of three rectilinear pistons
Prin 11

page_text: working in three correspondingly formed air chambers. To ensure the uniform
rotation of the crank shaft two fly wheels may be carried by it, intermediate of the
cranks which work the pistons.
Each piston is supported by bars fixed to it near its two sides; these bars are
parallel with the piston rod, and extend through openings in the ends of the air
chambers, and rest upon and are supported by friction rollers. Two rods thus
fixed to each piston near its central horizontal line will generally be sufficient, thus
the pistons will be supported at their centre instead of at their lower end as here-
tofore, and a steadier movement obtained. The ends of the air chambers are
provided with two sets of valves. The valves in the lower part of each end are
inlet valves, and those in the upper half are outlet valves.
Around the lower half of the chambers is an air passage communicating with the
up cast shaft of a mine, or with a passage leading to any place from which air is
required to be withdrawn.
A similar construction of apparatus might be used for forcing air, but for venti-
lating purposes it is better to withdraw air from the place to be ventilated than to
force air into it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Nixon in the Great Seal Patent Office on the 1st October
1879.
JOHN NIXON, of No. 117, Westbourne Terrace, in the County of Middlesex.
"IMPROVEMENTS IN APPARATUS FOR EXHAUSTING OR FORCING AIR FOR VENTILATING
COAL AND OTHER MINES, AND FOR OTHER PURPOSES."
In the Specification of a former Patent granted to me on the 15th November
1861, No. 2875, I described an arrangement of apparatus for withdrawing air from
coal or other mines. In this arrangement of apparatus two rectilinear pistons were
used, working to and fro in correspondingly formed air chambers. The pistons
had motion given to them by two cranks at right angles to one another on the
crank shaft of an engine.
With this apparatus the withdrawal of the air was irregular, and was not uniform
throughout the stroke or movement of the pistons; the consequence was that
pulsatory oscillations were set up in the air throughout all of the workings and
passages in the mine.
To remedy this defect I now form the apparatus with three air chambers, each
having in it a piston, and give motion to the pistons from three cranks equally
spaced around a cranked driving shaft; and in order to improve the construction of
the apparatus and to obtain a more steady and uniform movement of the pistons I
form the apparatus in the following manner :-
I give motion from a steam engine to a horizontal shaft, on which are three
cranks set at equal angles around the shaft. From the three cranks motion is
transmitted by connecting rods to the piston rods of three rectilinear pistons
working in three correspondingly formed air chambers. To ensure the uniform
rotation of the crank shaft two fly wheels may be carried by it, intermediate of the
cranks which work the pistons.
Each piston is supported by bars fixed to it near its two sides; these bars are
parallel with the piston rod, and extend through openings in the ends of the air
chambers, and rest upon and are supported by friction rollers. Two rods thus
fixed to each piston near its central horizontal line will generally be sufficient, thus
the pistons will be supported at their centre instead of at their lower end as here-
tofore, and a steadier movement obtained. The ends of the air chambers are pro-
vided with two sets of valves. The valves in the lower half of each end are inlet
valves, and those in the upper half are outlet valves.
Around the lower balf of the chambers is an air passage communicating with the
up cast shaft of a mine, or with a passage leading to any place from which air is
required to be withdrawn.
A similar construction of apparatus might be used for forcing air, but for venti-
lating purposes it is better to withdraw air from the place to be ventilated than to
force air into it.
Having thus described the nature of my Invention I will proceed to describe
more fully the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
The Drawings hereunto annexed shew apparatus constructed according to my
Invention. Figure 1 is a side view partly in section of the apparatus; Figure 2 is
a plan view of the same, also partly in section; Figure 3 is a vertical section on a
larger scale of one of the air chambers and the piston working within it.
A is an archway in connection with the up cast shaft; B, air passages leading
therefrom; C are the air chambers; D are the pistons working therein; E are the
bars by which the pistons are carried; F are the rollers on which the bars rest;
G are the piston rods which pass out from the air chambers; G* are guides for the

page_text: piston rods; H are connecting rods which couple the piston rods to cranks I on the
cranked driving shaft J; K, K; are fly wheels on the two parts of this shaft; L is a
steam cylinder for driving the shaft J; M are the upper or outlet valves, and N the
lower or inlet valves; O is the upcast shaft.
Having thus described the nature of my Invention and the manner of performing
the same I would have it understood that I claim,-
First. The combined arrangement of apparatus for exhausting or forcing air for
ventilating coal and other mines, and for other purposes, substantially as herein
before described and shewn in the Drawings annexed.
Second. The combination of the three rectilinear air chambers provided with
inlet and outlet valves, and having pistons working therein with a cranked driving
shaft formed with three throws or cranks equally spaced around the shaft, each
crank being coupled by a connecting rod with the piston rod of one or other of the
three pistons, substantially as herein before described.
Third. Supporting the rectilinear pistons of the air chambers by bars or girders
which rest on rollers, substantially as herein before described.
In witness whereof, I, the said John Nixon, have hereunto set my hand and
seal, this Thirtieth day of September, in the year of our Lord One thousand
eight hundred and seventy nine.