An Apparatus for Detecting Explosive Gas or Dust in the Atmosphere.
Year: 1899

page_text: Date of Application, 31st Oct., 1899
Complete Specification Left, 31st July, 1900-Accepted, 27th Oct., 1900
PROVISIONAL SPECIFICATION.
An Apparatus for Detecting Explosive Gas or Dust in the Atmosphere.
I, CHARLES EDWARD GLASCODINE SIMONS, The Hollies, Merthyr Tydfil, Glamor-
ganshire, Physician & Surgeon & Consulting Chemist, do hereby declare the
nature of this invention to be as follows.-
The
A substance possessing catalytic properties 18 introduced into the mixture
suspected to contain explosive hydrocarbon gases or explosive dust I prefer to
use spongy platinum and find that it acts best when it is heated When a substance
of this nature 18 introduced into the suspected atmosphere and if explosive gas or
dust be present two phenomena occur (A) Moisture 18 formed by the combustion
of the gas if it contain hydrogen, this moisture I condense on a bright surface so
that it can be observed and the quantity of moisture that is formed is taken as an
index of the amount of hydrogen present in combined or uncombined forms in
the atmosphere (B) The temperature of the spongy platinum iises and I
measure this 118e of temperature with a suitable thermometric apparatus
118e of temperature is proportionate to the amount of hydrogen and hydrocarbon
gas that may be present To detect explosive dust apart from explosive gases con-
taining hydrogen and carbon, in a mixture of an gas and dust I first filter &
quantity of the mixture through cotton wool or other suitable filtering media, to
free it from dust, and lead the temperature of the dust free mixture after it
passes the spongy platinum, then the mixture of the three substances is allowed
to flow through the apparatus and if a further increase in temperature is now
indicated by the thermometic apparatus hereafter called the thermometer it 18
due to the decomposition of the dust and its subsequent combustion. My apparatus
contains a suitable heating appliance such as a coil of wie heated by an electric
culent or a tube maintained at a sufficient degree of heat; the mixture of gas
air and dust flows through this chamber The spongy platinum is so placed that
it is also heated by the same means and the mixture is allowed to pass over and
around it. The thermometer is placed near the spongy platinum, so as to be
heated by it, the surface of the thermometer may be bright, and used to condense
moisture upon; the whole of the heating appliance and the spongy platinum and
the thermometer may be enclosed in a suitable chamber and the scale or the
registering portion of the thermometer may project from the said chamber for
convenience of obversation. Guards of wie gauze may be placed at the inlet and
the outlet of the said chamber to prevent any possibility of an explosion of gas
or dust within the said chamber reaching the outside atmosphere I also make
the appliance automatic in its action. This is done by means of (A) An electric
alarm thermometer arranged so that when the mercury in this instrument reaches
a determined temperature it shall complete an electie cucuit which may be made
to ring a bell or give a suitable alarm; or (B). The properties of a metallic
wire which is heated are made use of in the following manner When a metallic
we is heated it offers a resistance to the passage of an electric current which
increases with the rise of temperature in definite proportional iatio
If I pass

page_text: an electric current hereafter called cucuit 1, through a wire for the purpose of
heating the platinum sponge and I place this sponge so that any heat derived
from it heats the aforesaid wie, this further increase of heat increases the electrical
resistance of the wne. If the cucuit 1, contains in it a solenoid or coil or an
electromagnetic apparatus which 19 made to support a lever weighted at one end and
which is so balanced that the current is just suthcient to prevent the said lever
from falling and if the increased resistance be introduced into this cucuit, the
electromagnetic appliance will no longer be able to support the whole weight of
this lever On this lever falling it makes contact with a conductor and this contact
18 arranged so as to close an electic circuit called hereafter cucuit 2, which may
contain an annunciator bell on suitable appliance for the purpose of diceting
attention to the closure of cucuit 2 This appliance also automatically indicates
the failure of curient in circuit 1, and duects attention to the apparatus being out
of order by failure of current in cucuit 1
1
1000
An Apparatus for Detecting Explosive Gas or Dust in the Atmosphere.
I, CHARLES EDWARD GLASCODINF SIMONS, The Hollies, Merthyr Tydfil, Physician
& Surgeon & Consulting Chemist, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement.-
This
A substance having suitable catalytic properties heated to a suitable temperature
18 brought into contact with the atmosphere suspected to contain explosive dust
01 gases
If either or both of the above mentioned substances are present, an
increase of temperature takes place in the catalytic reagent, and products of com-
bustion are formed. Platinum wue, I have found to be a suitable catalytic
reagent, and I here describe methods of constructing apparatus which I have
found to be convenient for the above purposes A form of apparatus illustrated in
Fig 1, Sheet 1, 18 constructed as follows-A coil of platinum wire of sufficient
thickness 18 enclosed in a chamber communicating with the atmosphere through
wire gauze screens "G" In Fig. 1, Sheet 1, "A," represents the coil of platinum
we, "F," "F," 18 the chamber, and "G," "G," are the wire gauze screens.
coid "A," is heated to a sufficient degree of temperature by the current from the
battery or generator "C" The current from "C," passes first to a Wheatstone's
bridge composed of the metal strips of low resistance "L'," "L," "L" "L,"
arranged as shewn in Fig "1," Sheet "1," and the high resistance wire
"K,"
with the sliding contact piece "Y," making contact with "L," and "Z" The
small circles represent the contact terminals to which the leads "B," "B," and the
galvanometer leads "b," "b," and the resistance "E," are attached When the
curient from " A," is traced, it will starting from the left hand side of "C," be
found to pass to the contact piece "Y," thence from each side of "Y," along "Z,"
through "A." and E," to the small encle on "L", and thence back to the
right hand side of "C" The amount of current on each side will be proportional
to the difference in the resistance between "A," and "E" The resistance "E,"
is made equal to "A," when "A," is heated by its share of the current from "C,"
but if the temperature of "A," rises from any cause, more curient will be passed

page_text: 44
"
"
through "E." and therefore the potential at the two points at which the
Wires b," 0,
are fixed on "L" and "L" will no longer be equal, so the
galvanometer "D" will chew a deflection By sliding "Y," in the direction of
the greater resistance this difference of current can be equalised, and the distance
that "Y" is moved gives the difference between the resistances of "A" and "E"
This is indicated by the galvanometer coming back to its zero point. I graduate
the scale "K," in the following manner -I first arrange "A," and "E," so that
when current is passed through them as in Fig 1, Sheet 1, the indicator of "D,"
stands at zero, when "Y," is at the zero point in the scale "K" Then a mixture
of air and coal gas containing one per cent of gas is passed through "F," and the
amount of the deflection of "D," is noted, and "Y," 18 slidden along "K," suffi-
ciently to bring the indicator of "D," to zero again This gives the point 1%
on the scule of the instrument when graduated Further graduations are obtained
in like manner for the other graduations of the scale Instead of the galvano-
meter "D," I make use sometimes of a telephone placed in circuit "b," b,” and
when the telephone gives a loud sound on closing circuit "b," "b," by means of a
key it is taken as evidence that the resistances 'E," & "A," are unequal. By
sliding "Y," in the duection of the greater resistance the sound will get fainter
& will at length disappear The point of equal resistance can by this means
be determined with great delicacy. Instead of the resistance coil "E," in some
forms of apparatus especially those used in collieries it will be more convenient
to use an incandescent electric lamp of known resistance This apparatus may be
made in a portable and a fixed form. When portable the parts are assembled
together in or on a suitable case for "C" When made in a fixed form "A," may
be placed anywhere where the presence of explosive gas or dust is suspected,
and "C," may be placed in any convenient place for the production of electio
energy, whilst "D," and the Wheatstone's bridge may be placed in any position
suitable for observation Thus "A," might be placed in the airway of a
colliery, whilst "C", and "D," and the Wheatstone's badge might respectively
be in the engine house and the offices In this case the only precautions that
must be of necessity taken, are that the whole resistance of the leads from the
Wheatstone's bridge to "A," must be allowed for when during the calibration
of the instrument "E," is balanced against "A"
A second form of apparatus may be constructed as shown in Fig 2, Sheet 2 I
find however that the use of spongy platinum as mentioned in my Provisional
Specification is not absolutely necessary, as a heated coil of platinum wire has
sufficient catalytic properties, and simplifies the construction of the apparatus A
current hereafter called cucuit 1 18 made to traverse a coil of platinum wire A,"
enclosed in a chamber "F," "F," which is in communication with the atmosphere
through the wie gauze screens "G,"
" "G"
The current in circuit 1, also passes
through a solenoid or electromagnet "H" "H", "h," "h," of which "H," "H,"
are the coils and "h," "h," are the soft on coles
" "
In Fig 2, Sheet 2, "e,"
"
are metal brackets supporting "Y," and "S", and "f," 'f," are the contact
terminal sciews carrying the current to e," e 'S," is an adjustable contact
sciew making contact sometimes with "Y" "W." 18 an adjustable weight to
counterbalance "Y," and the magnetic pull on "Y," when "A," 18 unaltered in
resistance by external sources of heat The connecting piece between "Y,"
and "W," is pivoted beneath the contact screw shewn by the small circle on the
1ight hand bracket "," and thus "Y," is allowed to make contact with "S," or
to rest against the stop "," as shewn in the figure "C" is the source of
electricity, and "B," "B," the leads conveying curient from "C." A casing "d,"
18 shewn for enclosing "C," and acting as a support for parts of the apparatus
The encuit "?" I arrange to start at a battery" c," and to flow to the alarm "M,"
thence to the screw "8," and thence to "Y," when "S," and "Y," are in contact.
From the other side of the battery it flows to "Y," so that when "S," and "Y,"
are not in contact the circuit 18 open and not complete When the current in
circuit 1, diminishes from any cause, whether from increase in the resistance

page_text: "
of A," or the failure of output in "C," the cucuit "2" will be closed as the
pull of "H," "H," "h," "h," on "Y," will not longer be able to maintain "Y,"
in the position shewn in Fig. 2, Sheet 2, and "Y," "S," will come in contact and
the bell or alarm "M," will iing. This apparatus may be fixed or portable When
portable it is assembled in a convenient manner as aforesaid with regard to the
apparatus described in Fig 1, Sheet 1 When it is fixed the various parts may
be distributed as 18 found convenient A form of apparatus using a mercurial
thermometer for the thermometric device is shewn in Fig. 3, Sheet 3. A," 18
the coil of platinum wie, "B," "B," are the leads for the electric current
from "C," the source of electricity, "F," "F," 18 the chamber communicating
through the wire gauze screens 'G," "G," with the atmosphere, and which
contains the coil "A," and the mercurial thermometer "H" "$," is a wire which
passes through the open end of "H," as shewn in the figure and which may be
adjusted at any desued position in the cential tube of "H," so as to make contact
with the mercury in "H," at any desued point The coil "A," surrounds the
bulb of "H," and when heated will cause the mercury in the nailow portion of
the tube to 11se in the usual way. A second electric cucuit which is kept open
until "H," registers the temperature determined upon when ailanging the
apparatus, 18 completed as follows. From the battery "c," the current flows to
the alarm "M," and thence to "S" When "S," is not in contact with the
mercury in 'H," it 18 interrupted at the end of "S," by the space "1" From
the other side of the battery it flows to the end of "H," where it terminates in a
wire which is melted into the glass of "H," so as to make contact between the
mercury inside "H," and the lead "6" When "A" increases in temperature
owing to any outside cause, "H," indicates the increase of temperature When
the temperature reaches the pre-arranged limit the space "1," 18 occupied by
the mercury in "H," expanding and contact is made with "S," and "M," there-
fore rings owing to the circuit "b," "," being completed This apparatus may
be fixed or portable as aforesaid with regard to the previously described apparatus
In the use of all the above apparatus dust and gas may be differentiated by
filtering the au that is to be tested through cotton wool or other filtering medium,
which will retain the dust & prevent its passing into the chamber containing the
catalytic reagent The apparatus will then register the amount of explosive gas
that may be present The air containing both the gas and the dust is next allowed
to pass into the chamber containing the catalytic reagent, & the apparatus then
indicates the amount of the mixed explosive substances present. By deducting
the amount of the gas that is already found to be present the amount of the
explosive dust will be indicated. If the apparatus indicates that no gas is present,
the amount of the dust can be found directly, as the indication of the instrument
will be due to dust alone In all forms of the apparatus the first sign of gas being
present is the deposition of moisture on cool surfaces placed near "A
forms of the apparatus spongy platinum may be enclosed in the coil "A", which
for this purpose requires to be made longe This increases the heat produced by
the apparatus Any catalytic reagent that can be diawn into wire may be used in
this apparatus, even if it is a nonconductor of electricity, as all that is necessary
to do with it is to place it so that its rise in temperature reacts on a thermometiic
device
In all
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim 18:
(1). A means of detecting the presence of explosive gases by the changes of
temperature they cause in a catalytic reagent
(2) A means of detecting explosive dust by the changes of temperature that it
causes in a catalytic reagent
(3). An apparatus for automatically signalling the presence of the presence of

page_text: explosive gas or explosive dust, or both explosive gas & explosive dust in the
atmosphere when either exceed a determined limit.
(4) An apparatus as described above for the purpose of detecting explosive
gases or explosive dust in the atmosphere the apparatus to work automatically
Dated this 20th day of October 1900.