IMPROVEMENTS IN APPARATUS FOR DETECTING AND MEASURING SMALL QUANTITIES OF INFLAMMABLE GAS PRESENT IN COAL MINES AND OTHER LOCALITIES." PROVISIONAL SPECIFICATION
Year: 1880

page_text: LETTERS PATENT to Edward Henry Torlesse Liveing, of No. 52, Queen
Anne Street, Cavendish Square, in the County of Middlesex, for an Invention
of "IMPROVEMENTS IN APPARATUS FOR DETECTING AND MEASURING SMALL
QUANTITIES OF INFLAMMABLE GAS PRESENT IN COAL MINES AND OTHER
LOCALITIES."
PROVISIONAL SPECIFICATION left by the said Edward Henry Torlesse
Liveing at the Office of the Commissioners of Patents on the 22nd November
1880.
EDWARD HENRY TORLESSE LIVEING, of No. 52, Queen Anne Street, Cavendish
Square, in the County of Middlesex. "IMPROVEMENTS IN APPARATUS FOR
DETECTING AND MEASURING SMALL QUANTITIES OF INFLAMMABLE GAS PRESENT
IN COAL MINES AND OTHER LOCALITIES."
My improvements relate to a method and apparatus previously invented by me
for detecting and measuring inflammable gas in the air of coal mines and other
places, such as the holds of ships, the waste flues of blast furnaces, &c.
This method was based on the fact that if a platinum wire be made by an
electric current to glow with a certain intensity of red heat in pure air, and be
then exposed to air contaminated with inflammable gas, a marked increase of
brilliancy in the heat of the wire is noticeable. To avail myself of this fact I
contrived the following apparatus :—
-
At either end of a brass tube was arranged a spiral of fine platinum wire
electrically connected to a magneto-electrical machine by which they could be
raised to a red heat at pleasure. They were so arranged as to glow with equal
brilliancy when the current of the machine was made to circulate through them.
Price £1

page_text: One of the wires was enclosed in a small air tight casing partly of glass, and the
other enclosed in a cap partly of wire gauze and partly of glass; to this wire the
air or gas drawn into the instrument for examination had access while the.other
wire was protected by its air tight casing. On turning the electrical machine both
wires glowed with equal brilliancy so long as the atmosphere within the instrument
was free from inflammable gas, but if gas was present a difference in brilliancy
was observable between the wires, and this difference was measured by means of a
simple form of photometer, consisting of a small angular screen which could be
moved between the two wires until equal illumination of its two surfaces was
attained, this operating in combination with a scale (determined by actual
experiment with known percentages of gas) was the means adopted to measure the
percentage of inflammable gas present in the sample of air examined; the outer brass
tube or casing of the instrument had two entrance tubes through which the
sample was drawn into the instrument for examination by taking a breath
through it.
I have since found that before the platinum wires can be employed for the
detection and measurement of small quantities of actual fire damp, it is necessary
before the scale of percentages is determined that they be subjected to the following
preparation, which constitutes one of my present improvements, namely, heating
them to a red heat in an atmosphere containing inflammable gas of low igniting
point, such as hydrogen, common coal gas, or the vapour of some volatile combus-
tible liquid; or less efficiently by heating them to a white heat in a tolerably rich
mixture of marsh gas and air for some time, after which the platinum acts
efficiently when heated to redness, and exposed to air containing even a very
small percentage of fire damp; but without such preparation new platinum wires
may be heated to redness and exposed to air containing small quantities of fire
damp without exhibiting any increase of brilliancy whatever. After such pre-
paration the scale of percentages is determined by filling the instrument with
known mixtures of fire damp and air, and noting how far the screen has to be
moved to attain equal illumination of its surfaces.
Another of my present improvements consists in an alteration in the construction
of the instrument, and a ready means of replacing the platinum wires in case of
accidental damage or melting, &c.
I make the chamber of the instrument no
longer of a brass tube, separate from the electrical machine, as in the earlier plan,
but construct it of wood or other suitable material, and attached to the casing of
the electrical machine; this chamber is made with a lid that can be opened at
pleasure when it is desired merely to test the atmosphere surrounding the instru-
ment, as in the air-way of a mine, but is likewise provided with two small entrance
tubes, whereby in conjunction with an india-rubber tube a sample of air or gas may
be drawn from any place that it is required to test. The opening of the lid
affords also a ready means of replacing the platinum wires.
The small casings
that contain them are closed at one end by a plug of non-conducting material, and
attached to this are two semi discs or plates of metal electrically connected with
either end of the platinum wire; at each end of the chamber of the instrument
are a pair of stout metal springs or plates, one of each pair forming terminals
to the electrical machine, while the other two are connected by a copper wire ;
behind these springs can be slid the edges of the semi-discs of metal before men-
tioned, thus completing the electrical circuit through the platinum wire. By the
above described arrangement the platinum wires can be replaced by fresh ones
with the greatest ease.
Another of my improvements relates to the scale which in the earlier plan I
placed outside the instrument, a lamp being employed to read it. I now place the
scale within the chamber of the instrument near the sliding screen, where the
heated platinum wires afford sufficient light to read it by, and I make the glass
window through which the screen is viewed sufficiently long to admit of the whole
range of the scale being visible at once, the percentage is then seen directly the

page_text: screw is moved to the point of equal illumination, which movement is effected by
aid of a bar passing through the case of the instrument.
Another of my improvements relates to an alteration in the construction of the
magneto electrical machine, whereby the danger of sparks produced by the ordinary
form of break or commutator is avoided. I replace the break by the following
arrangement:-One end of the coil of wire on the armature is in electrical contact
with the armature, and the other end of the coil ends in an insulated metal wire
passing through one of the axes of the armature, which is perforated for that
purpose, and the end of this wire projects beyond the bearing, and an insulated
metal spring presses against its end, thus forming one terminal of the machine
while the bearings of the armature form the other.

page_text: .
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Henry Torlesse Liveing in the Great Seal Patent
Office on the 19th May 1881.
45
EDWARD HENRY TORLESSE LIVEING, of 52, Queen Anne Street, Cavendish
Square, in the County of Middlesex, Mining Engineer. IMPROVEMENTS IN
APPARATUS FOR DETECTING AND MEASURING SMALL QUANTITIES OF INFLAMMABLE
GAS PRESENT IN COAL MINES AND OTHER LOCALITIES."
My improvements relate to a method and apparatus previously invented by me
for detecting and measuring inflammable gas in the air of coal mines and other
localities, such as the holds of ships and the flues of furnaces, &c. The method is
based on the fact that if a platinum wire be made by an electric current to glow
with a certain intensity of red-heat in pure air, and be then exposed to air contami-
nated with inflammable gas or vapour, a marked increase in the brilliancy in the
heat and light given out by the wire is noticeable. To avail myself of this fact I
contrived the following apparatus-At either end of a brass tube was arranged a
spiral of fine platinum wire electrically connected to a magneto electrical machine.
They were so arranged as to glow with equal brilliancy when the current of the machine
was made to circulate through them. One of the wires was enclosed in a small air tight
casing partly of glass, and the other enclosed in a cap partly of wire gauze and partly
of glass; to this latter wire the air or gas drawn into the instrument for examination
had access while the other wire was protected by its air tight casing. On turning the
electrical machine both wires glowed with equal brilliancy so long as the air within
the instrument was free from inflammable gas, but if gas was present a difference of
brilliancy was observable between the wires, and this difference was measured by
means of a simple form of photometer, consisting of a small angular screen which
could be moved between the two wires until equal illumination of its two surfaces
was attained. This screen was attached by an arm to a small glass window, the
two together. being capable of moving in a slot in the brass body tube of the
instrument. This screen operating in combination with a scale (determined by
actual experiment with known percentages of gas and graduated on the outside of
the brass chamber tube of the instrument) was the means adopted to measure the
percentage of inflammable gas present in the sample of air examined. The brass
chamber tube or casing of the instrument was made airtight with the exception of
two entrance tubes through which the sample was drawn into the instrument for
examination by taking a breath through it. I have since found that before new
platinum wires can be employed for the detection and measurement of small
quantities of actual fire damp, it is necessary before the scale of percentage is
determined that the wires be subjected to the following preparation, which
constitutes the first of my present improvements, namely, heating them to a red
heat and exposing them for a short time to an atmosphere containing any
inflammable gas of low igniting point, such as hydrogen, olefiant gas, common coal
gas, or the vapour of some volatile combustible liquid; or less efficiently by heating
them to a white beat in a tolerably rich mixture of marsh gas and air for some
time, after which preparation the platinum acts efficiently when heated to redness
and exposed to air containing even a very small percentage of fire damp; but with
out such preparation new platinum wires may be heated to redness and exposed to
air containing small percentages of fire damp with out exhibiting any increase of
brilliancy whatever. The platinum wire I now employ is one five hundredth of an
inch in diameter; 1 form it into small spirals or rather helices, which are made by
coiling it upon a piece of wire one hundredth of an inch in diameter; I make ten
revolutions, and on removing the spiral from the wire I stretch the spiral out until
it has some exact length, such as one tenth of an inch. The spirals are then soldered

page_text: to the insulated connection wires in the manner shewn in Figure 4.. In the above
mode of preparation I use air containing about 3 per cent: of coal gas which answers
well though the proportion is not important. The wires very soon attain. their
maximum sensitiveness; after which the scale of percentages is determined by filling
the instrument with known mixtures of fire damp and air and noting how far the
screen has to be moved to obtain equal illumination of its surfaces. By making all
the platinum spirals with great care exactly alike the same scale may be made to
serve for any pair of spirals. The second of my present improvements consists in
an alteration in the construction and general arrangement of the instrument
whereby an easy means of access to and replacement of the platinum wires is
afforded, and the general external form of the instrument is rendered much more
compact and convenient for use in the mine. I make the chamber of the instrument
no longer of a brass tube connected only to the electrical machine by metallic con-
ductors, but I now construct it of wood attached to and forming part of the casing
or box containing the electrical machine. The general arrangement of the two, as
now combined, is shewn in the Figures 1 and 2, in which A, A; is the chamber of
the instrument; B, B, the fat box containing the Siemens armature and
permanent magnets of the electrical machine; D is a portion of the casing con-
taining the driving wheels of the electrical machine, and from it projects the driving
handle E. The external form is now designed so that it can be held firmly and con-
veniently by the experimenter when using it in the mine where there is no support to
rest it upon, it being intended in such case that the experimenter should stoop or sit
down upon his heels with his back against the coal, and resting the instrument upon
his knees should place his left arm upon the upper surface of the box B and should
thus retain it firmly in position while he turns the driving handle E with his right
hand, his left hand being still free enough to move the slide rod, F (Figures 2
and 3) and by it the screen G. The chamber A is made with a hinge lid H,
Figure 1, which closes it tolerably airtight, the margin of the lid being covered.
with leather, indiarubber, or other soft material. The lid can be opened at pleasure
when it is simply desired to test the atmosphere surrounding the instrument, as in
an airway of a mine, but the chamber is also provided with two small entrance
tubes K and L as in the early form of instrument, whereby in conjunction with a
flexible tube a sample of air or gas may be selected from any desired locality. by
drawing a breath through the instrument, the lid being of course closed when the
instrument is thus used. The opening of the lid affords also a ready means of
obtaining access to and replacing the platinum spirals in case of accidental melting
or damage. They are now supported and arranged in the manner shewn in
Figures 3, 4, and 5. Figure 4 is a longitudinal section, actual size of one of the
small casings containing the platinum wires. The one shewn is that of the
working wire or that to which the gas has access; the cover is therefore partly of
wire gauze, shewn dotted; the end M is of glass, the rest is of brass tube and the
lower end is closed by a plug N of nonducting material (I.use wood or ebonite)
and attached to this are two semidiscs or plates of metal, O and P, Figures 4 and 5,
electrically connected with either end of the platinum spiral R by.conducting wires
in the manner shewn. At each end of the chamber of the instrument (shewn one
half actual size in longitudinal section in Figure 3) are a pair of stout metallic
springs or plates S, S, S, (one only of each pair is seen in the Figure); one of each
pair form the terminals of the electrical machine, whilst the other two are
metallically connected. Behind these springs can be slid the edges of the
semidiscs and P, Figures 4 and 5 of the wire plugs before mentioned, thus
completing the electrical circuit through the platinum wire. Figure 3 shews the
wire plugs secured in position by the springs at either end of the chamber. By
the present arrangement the platinum wires and their casings can be removed and
replaced with the very greatest ease, and a certainty of good metallic contact is
ensured. My third improvement relates to the scale of percentages. In the earlier
plan I graduated this scale upon the outside surface of the brass chamber tube of
the instrument, the slide carrying the small glass window and photometer screen

page_text: acting as the index, and the light of a safety lamp being employed to read it. I now
place the scale within the chamber of the instrument in close proximity to the
sliding screen in such a position that the light of the platinum wires is sufficient to
read it by. Figure 3 shews the arrangement in which G is the small angular
screen movable by the slide rod F; Y is the scale of percentages, and W is a glass
window in the lid of the chamber of sufficient length to view the whole range of
the scale Y, so that the percentage of gas can be read off directly the screen has
been moved to the point of equal illumination of its two surfaces. I also now
make this scale adjustable, so that slight fluctuations in the position of the zero
point between the pairs of platinum wires can be corrected. This adjustment is
effected by the small thumb screw thumb screw and slot X, Figure 1.
My fourth improvement relates to the prevention of sparks at the break of the
electrical machine. In the early instrument I used the old form of Siemens'
armature with its usual form of break or commutator; I now employ the
arrangement shewn in section in Figure 6. One end of the coil of wire upon the
armature is in metallic contact with the core of the armature, and the bearings
becomes therefore one pole of the machine; the other end of the coil of wire
terminates in a stout insulated wire passing through one of the axes of the
armature perforated for that purpose; the end of this wire is brought to a smooth
rounded point and presses against a polished steel spring Z, Figure 6, and this
spring forms the other pole of the machine; by this means very little friction
and an entire absence of sparks is ensured.
I will now in conclusion point out what I consider novel and original in the
foregoing improvements, and therefore claim as the Invention secured to me by the
herein before in part recited Letters Patent.
First. Subjecting the platinum wires to a preparation in order to render them
sensitive and constant in their action prior to determining the scale of percentages
for firedamp.
Second. Constructing the chamber of the instrument with a door or lid for the
purpose of permitting easy admission of the air sample and also of easy access to
the platinum wires; the combining this chamber with the electrical machine so as
to form one compact and convenient form of instrument for use in the mine, and
also the mode of replacing the platinum wires by which the metal terminals of
the wires slide under or behind metal springs or plates.
Third. Arranging the scale of percentages in such a manner that the light of the
platinum wires is employed to read it.
Fourth. Combining the electrical machine having a non spark producing form of
break (or rather substitute for a break) with the instrument, so as to avoid the
danger that existed in the early form of instrument of firing gas by sparks from
the break or commutator.
In witness whereof, I, the said Edward Henry Torlesse Liveing, have
hereunto set my hand and seal, this Fourteenth day of May, in the year of
our Lord One thousand eight hundred and eighty one.