Variations of a Barometer.
Year: 1885

page_text: Variations of a Barometer.
I
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of my invention for IMPROVEMENTS IN APPARATUS FOR SIGNALLING OR
INDICATING THE VARIATIONS OF A BAROMETER" to be as follows:-
"
This invention relates to apparatus for signalling or indicating the variations of
a barometer, chiefly designed for ascertaining when emanations of gas or fire-damp
in collieries are likely to occur.
The communicator of this invention has discovered that the emanation of gas
from coal is inversely proportionate to the pressure of the atmosphere, that is to
say, that the emanation increases with a diminishing air-pressure, and diminishes
with an increasing air-pressure.
,'
Besides the extent of the fall of the barometer, the rapidity of the fall is of
special importance, as, in the case of a rapid decrease of the atmospheric pressure,
the ventilating machines or fans are incapable of supplying air fast enough to
overcome the great volumes of gas emanating from the coal. The increase of the
pressure and the consequent rise of the barometer, however, remove the danger at
once. Accordingly, by carefully observing the barometer, the approach of danger-
can be ascertained and precautionary measures taken.
The uninterrupted observation of a barometer is, however, a duty which can'
scarcely be exacted for any long time. The present invention therefore consists in
providing an instrument whereby the decrease of the atmospheric-pressure and the.
accompanying danger are indicated.
This instrument comprises a clock and a bell. The barometer is so connected
with the bell that the latter signals the number of millimeters which the barometer
has fallen, by the number of strokes which it gives. This signal is however only
given at definite periods of time say for instance every 8 hours, so that the number
of strokes of the bell corresponds to the number of millimeters which the barometer
has fallen during the last 8 hours which have passed. For this purpose the clock

page_text: must disengage the mechanism for signalling the fall of the barometer. When
the barometer rises all signals cease and the mechanism returns to its normal
position.
manners.
It is evident that this function of the instrument can be attained in different
The barometer can be an aneroid barometer or a mercurial barometer;
ordinary repeater striking mechanism or an electric bell can serve for signalling,
and the connection of the clock with the bell can be broken by electric or mechanical
means.
Among the various constructions which can be employed I will describe two as
being especially suitable..
According to the first construction the barometer contains 6 or 7 boxes or
chambers on the aneroid system, which transmit their motion to a shaft with
which are connected a hand and a short lever. The said hand carries a small
wheel of platinum and silver or other suitable alloy, which makes electrical
contact with a metallic ring provided with a scale..
The said ring, hand, and short lever are in an electrical circuit.. Small plates of
ivory are arranged in the metallic scale and small platinum plates, whose surfaces
are in the same plane as the surfaces of the small ivory plates alternate with
the latter.
i
"
The end of the said short lever moves between the limbs of a fork and can only
make contact with the latter when the barometer is rising, as one limb of the fork
is covered by an ivory plate. A sliding contact-spring bears upon the fork and
serves at the same time as a brake for the fork.
Now if the barometer is falling the electric circuit is closed at every millimeter
by the roller on the hand making contact with a platinum strip. An electro-
magnet in this circuit is thereby excited and a second lever is set in action. The
armature of the said electro-magnet and the second lever turn upon the same axis;
they are, however, only connected by a latch or hook one arm of a bell crank lever,
Bo that after the attraction the latch or hook is detached by the other arm coming
into contact with an adjusting screw whereby the second lever falls back. The
effect of this is that even with a comparatively long contact at any particular
platinum strip the second lever acts rapidly and only once. When this platinum
strip is passed the contact ceases, the armature is drawn back by a spring, and the
latch or hook again engages with the second lever.
Whenever the barometer falls one millimeter, an escapement or ratchet wheel is
pushed one tooth forward. Upon the axis of the said ratchet wheel is fixed the
stepped snail wheel of the striking mechanism, and a cord pulley. The ratchet
wheel is provided with a stop, in order that the snail wheel cannot be moved
beyond the first and tenth step.
The striking mechanism which is disconnected every minute by the clock lifting
a latch, will indicate by the number of strokes the number of millimeters which
the barometer has fallen.
The stepped snail-wheel may be so arranged that the striking mechanism will
operate once every minute even when the barometer is rising. Then, in falling
1 millimeter, a second stroke is added, and so on.
This arrangemeüt has the advantage that the stroke taking place every minute
indicates the proper operation of the apparatus. If the arrangement of the striking
mechanism is to be such that the latter strikes only when the barometer is falling,
and just as often as the fall amounts to one or more millimeters, a stop can simply
be caused to enter into the fly pinion of the striking mechanism, by a maguet
which is excited when the barometer is rising.
As already observed, it has been found by observation that not only the extent
but especially the rapidity of the decrease of the atmospheric pressure considerably
increases the emanation of gas. If, for instance, the barometer falls 10 millimeters
in from 8 to 10 days, the efflux of gas will not be very considerably increased, as
the ventilation can overcome the gases passing out slowly, whereas if the barometer
falls 10 millimeters in one day, the emanations of gas will be of a very dangerous
د

page_text: kind. The apparatus is therefore so arranged that the signalling of each millimeter
of the fall of the barometer does not continue through the whole time of the fall,
but only at intervals of say 8 hours; in other words, the number of the strokes of
the striking mechanism corresponds with the number of millimeters which the
barometer has fallen during the past 8 hours. This result is effected by the
following arrangement.
.
A disc is provided having 64 pins or pieces capable of being turned upon pivots
so as to extend beyond the periphery of the disc. The said disc is moved a distance
corresponding to th of its periphery during every quarter of an hour, by the
clock-work; it therefore makes half a revolution in 8 hours. As often as, the
second lever moves the escapement or ratchet wheel one tooth forward it throws
aside a pin on the said disc by means of a bell-crank lever. After 8 hours this pin
comes into contact with a projection on a third lever, thereby pressing the said
lever back and effecting the disconnection of the ratchet wheel and snail wheel,
whereby the latter is caused to pass back one tooth. The pins thrown aside are
raised again by an inclined plane fixed to the casing of the instrument.
A hook on the left hand of the third lever prevents the escape-wheel moving back
more than one tooth. This hook can move outwardly upon a hinge. In case the
disconnection of a fourth lever should coincide with a forward motion of the second
lever, the disconnection of the fourth lever cannot take place completely, in .con-
sequence of the advance of the ratchet wheel, if the hook bearing against the tooth
of the ratchet wheel cannot pass to the left.
When the barometer rises, an electric circuit is closed, an electro-magnet in this
circuit is excited, the fourth lever is drawn back, and the ratchet wheel, together
with the stepped snail wheel, is completely disconnected so that it turns back to
step 1. By the retreat of the fourth lever a spring thereon is moved away from
its opposite contact whereby the circuit is interrupted and thus renders an excite-
ment of the first mentioned electro-magnet impossible. This spring contact is so.
constituted that in the ordinary disconnection of the fourth lever the circuit is not
interrupted but only when the fourth lever is completely drawn back by the
electromagnet. When, within 8 hours, the barometer falls, rises, and falls again,
the pins thrown aside during the first fall would make the position of the stepped
snail-wheel wrong in the second fall. With every rise of the barometer, therefore,
a general disconnecting device must engage and raise all the pins turned down.
This result is effected by an eccentric disc, which being connected with the said
cord pulley, turns in the opposite direction to that of the clock hand when a latch,
is disconnected, and raises in this motion all the pins which may have been thrown
down. This disconnection of the latch..takes place instantaneously when the
ratchet-wheel is moved back, when the barometer rises, by means of an arm
arranged in a stop pin on the ratchet wheel, which arm makes contact with a
spring covered on the left-hand side with ebonite, thereby instaneously closing a
third electric circuit.
Auxiliary. bells may be erected in any desired places and caused to operate by
the spring contact and a local battery as soon as the striking mechanism is set in
motion.
According to the second construction the making of the electrical contacts by
the barometer takes place in a similar manner to that just described, only it is
simplified in that the fork is divided into two parts by insulating material and the
hand is insulated from the axis upon which it is mounted, whereby the closing of -
the first circuit is only possible when the barometer is falling and the closing of
the other circuit only when the barometer is rising; the spring contact is then
unnecessary.
When the barometer is falling a lever is operated once at every millimeter of
movement of the barometer by the closing of the circuit of an electromagnet,
thereby causing the ratchet wheel and the stepped snail wheel to advance one
tooth or one step respectively. With the stepped snail wheel is connected an
ordinary repeater striking mechanism. The ratchet-wheel and the stepped wheel

page_text: have 11 teeth or steps respectively, and the first step of the stepped wheel is so
high that with this step a disconnection of the striking work does not take place
at all; accordingly the striking mechanism does not operate when the barometer is
rising. The next step which corresponds with a fall of 1 millimeter gives one
stroke per minute.
:
When the barometer is rising a second. electromagnet is excited in consequence
of the closing of the other circuit, a stopping lever is attracted, and the ratchet
wheel, together with the stepped snail wheel, is disconnected, whereby they are
brought back to their original positions.
The disconnection of the striking mechanism after a definite period of time,
say 8 hours, takes place in quite a different manner from that described in the
first construction.
The device is similar to that in Hipp's chronoscope. The movable spindle
carries Hipp's needle, a cord pulley, and a disc. The disc has a tappet which after
a complete revolution makes a momentary contact with a spring thereby closing
third circuit. The current of this circuit flows also around the second electro-
magnet. A second disc which is toothed radially is caused to revolve once in
8 hours by a wheel of the clock mechanism.
'As often as the ratchet wheel is pushed forward one tooth, it forces the stopping
lever, back and the latter presses the movable spindle to the right. The needle is
thereby shifted from between the teeth of the second disc, and the first disc is
turned by a weight into its original position. As soon as the tooth has passed by,
a spring forces the inovable spindle back, the needle places itself between the
teeth of the second disc, and the said movable spindle is now moved away by the
clock work until, after a lapse of 8 hours, the contact takes place, whereby through
the closing of the third circuit the needle is shifted out again and the first disc
passes into the original position. When the barometer is rising, the closing of the
first circuit performs the same operation.
Now, if within 8 hours after the first millimeter fall a second fall of the
barometer of 1 millimeter occurs, the first disc passes to its original position and
the striking mechanism now gives a double signal if during the 8 hours no fall or
rise of the barometer has taken place.
.
This somewhat modified manner of signalling has the advantage that after a
fall of several millimeters, the bell signals cease simultaneously 8 hours after the
last millimeter fall, which for the purpose of giving warning is in no way a
disadvantage in the working of mines.

page_text: Variations of a Barometer.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 invention relates to apparatus for signalling or indicating the variations of
á barometer and is chiefly designed for ascertaining when emanations of gas or fire-
damp in collieries, are likely to occur. The communicator of this invention has
discovered that the emanation of gas from coal in coal mines is inversely
proportionate to the pressure of the atmosphere, that is to say, that, the emanation
increases with a diminishing air-pressure and diminishes with an increasing air:
pressure.
Besides the extent of the fall of the barometer, the rapidity of the fall is of
special importance, as, in the case of a rapid decrease of the atmospheric pressure,
the ventilating machines or fans are incapable of supplying air fast enough to
overcome the great volumes of gas emanating from the coal. The increase of the
atmospheric pressure however removes the danger at once.
Accordingly, by carefully observing the barometer, tlie approach of danger can-
be ascertained and precautionary measures taken.
The uninterrupted observation of a barom-ter is, however, a duty which can
scarcely be expected from any one for a length of time. The present invention
therefore consists in providing an instrument whereby the decrease of the
atmospheric pressure and the concomitant danger is indicated.
This instrument comprises a clock and a striking apparatus. The barometer is
so connected with the striking apparatus that the latter indicates the number of
millimetres which the barometer has fallen by the number of strokes which, it
gives. This signal however is only given for a definite period of time say, for
instance 8 hours, so that the number of strokes of the bell corresponds to the
number of millimetres which the barometer has fallen during the eight hours
which have passed. For this purpose the clock must disengage the mechanism
for signalling the fall of the barometer at the expiration of every eight hours.
When the barometer rises the mechanism may be so arranged that no signals
are given, the mechanism remaining in its normal position.
It is evident that the instrument can be made to operate in different manners.
The barometer can be an aneroid barometer, or a mercurial barometer. Ordinary
repeater striking mechanism or an electric bell can serve for signalling, and the
connection of the clock with the bell can be broken by either electrical or
mechanical means.
Among the various constructions which can be employed I will describe two as
being especially suitable.
In the accompanying drawings
Figures 1, 2, 3 and 4 are views illustrating one form of construction, and
Figures 5 and 6 are views of a modification.
According to the first construction shown in Figures 1 to 4 the barometer.
contains 6 or 7 boxes on the aneroid system as shown in Figure 1. which boxes
transmit their movements to a shaft a with which are connected a band ẞ and a
short lever R. The. said hand. carries a small wheel P.of platinum and, silver.or

page_text: other suitable alloy, which wheel makes electrical contact with a metallic ring F
marked with the scale of the barometer.
The said ring, hand, and .short lever are in. an electrical circuit 1, 2. Small
plates T of ivory are arranged in the metallic ring F, and small platinum plates T¹
whose surfaces are in the same plane as the surfaces of the small ivory plates
alternate with the latter.
The end of the lever R moves between the limbs of a fork Q and can only make
contact with the latter when the barometer is rising, as one limb Q¹ of the fork is
covered with an ivory plate.
O is a sliding contact-spring which bears upon the fork Q and serves at the same
time as a brake for the latter.
Now if the barometer. is falling the electric circuit 1-2 is closed at every
millimetre by the roller P on the hand ẞ making contact with a platinum strip T
An electro-magnet in this circuit is thereby energized and attracts its armature G
which turns upon a pivot. A lever H (Figure 2) is mounted upon the same pivot
as the armature G and is connected thereto by a latch J on one arm of a bell
crank lever, so that as the armature moves toward the magnet the latch is detached
by the other arm of the bell crank lever coming into contact with an adjusting
screw J, whereby the lever H falls back. The effect of this arrangement is that
even with a comparatively long contact at any particular platinum strip the
lever H acts rapidly and only once. When this platinum strip is passed the contact
ceases, the armature G is drawn back by a spring and the latch J again engages
with the lever H.
..
Whenever the barometer falls one millimetre and the lever H is moved an
escapement or ratchet wheel D is pushed one tooth forward. Upon the shaft of
the said ratchet wheel D is fixed the stepped snail wheel A Figure 4 of the
striking mechanism and a cord pulley E (Figure 3). The ratchet wheel D is
provided with a stop, in order that the snail wheel A cannot.be moved beyond the
first and tenth steps. The striking-mechanism is arranged to be disconnected
every minute, by the clock lifting the latch B, the number of strokes on the bell
indicating the number of millimetres which the barometer has fallen.
As shown in the drawing the stepped snail wheel is so arranged that the striking
mechanism will operate every minute even when the barometer is rising, so that in
falling an additional stroke is added for each millimetre.
This arrangement has the advantage that the striking taking place every minute,
indicates that the apparatus is in proper operation.
If the operation of the striking mechanism is to be such that the latter strikes
only when the barometer is falling, and then only when the fall amounts to one or
more millimetres, a stop can be caused to engage with the fly pinion of the striking
mechanism by means of an electro-magnet which is energized when the barometer
is rising.
As already observed, it has been found that not only at long but especially, at
rapid falls of the barometer the emanation of gas considerably increases. If, for
instance, the barometer falls 10. millimetres in from 8 to 10 days, the efflux of gas
will not be very considerably increased, as the ventilation can overcome the gases
passing out slowly; 'whereas, if the barometer falls 10 millimetres in one day, the
emanations of gas will be very dangerous. The apparatus may therefore be so.
arranged that the signalling of each millimetre of the fall of the barometer does
not continue for an indefinite time but is only given every 8 hours, in other words,
the number of the strokes of the striking mechanism only corresponds with the
number of millimetres which the barometer has fallen during the past 8 hours.
This result is effected by the following arrangement.
"
C is a disc provided with 64 pins or bars S capable of being turned upon pivots
so as to project laterally from the disc. The said disc is moved by the clock-work
a distance corresponding to 1th of its periphery every quarter of an hour it
therefore makes half a revolution in 8 hours. As often as the second lever H
moves the e
escapement or ratchet wheel D one tooth forward, it throws aside a. pin.

page_text: on the disc C by means of a lever has shown in Figure 3. After 8 hours this pin
comes into contact with a projection on a lever V fixed on the same axis as the
armature lever U as shown in Figure 3; thereby pressing the arm u of the lever U
against the arm n of the pawl N and effecting. the disconnection of the ratchet
wheel and snail.wheel from the said pawl whereby the snail wheel is caused to
move back one tooth by means of the weighted cord on the pulley E. The pins
thrown aside are raised again by an inclined plane K fixed to the casing of the
instrument.
A pawlu on the left hand arm of the lever Uprevents the escapement wheel D
moving back more than one tooth. This pawl can move upon a pivot.
In case the disconnection of the stop lever or påwl N should coincide with a
forward motion of the lever H the disconnection of the stop. lever N cannot take.
place completely, as, during the advance of the ratchet wheel, the pawl-u would'
bear against the teeth of the said ratchet wheel and would not allow the lever U
to move far enough.
..
When the barometer rises, the electric circuit is closed by the contact of the short
arm R with the uncovered limb of the fork Q. The electro magnet in this circuit
is then excited, the stop lever N is drawn back, and the ratchet wheel together with
the stepped snail wheel are completely disconnected, so that they turn back to
step 1. By the movement of the lever N the spring contact N¹ is moved away
from its opposite contact whereby the circuit 1-2 is interrupted and thus renders
impossible the energizing of the electromagnet inserted in the said circuit. The
spring contact N1 is so arranged that in the ordinary movements of the lever N by
the lever Ụ the circuit is not interrupted, but only when the lever N is completely'
drawn back by the electromagnet in the circuit 1-3.
:.
This
When within 8 hours the barometer falls, rises and falls again, the pins thrown
aside during the first fall would make the position of the stepped snail wheel wrong
for the second fall. With every rise of the barometer, therefore, a general discon-
necting device must engage with and raise all the pins turned down. This result
is effected by the excentric disc W which being connected with a cord pulley c turns
in the opposite direction to that of the clock hand when the latch x is disconnected,
and raises in this motion all the pins which may have been thrown down.
disconnection of the latch a takes place directly the ratchet wheel D is moved back
when the barometer rises, by means of an arm y arranged on the stop pin on the
ratchet wheel D, which arm makes contact with a spring y¹ (covered on the left
hand side with ebonite) thereby instantaneously closing the electric circuit 4-5
and energizing an electro magnet therein of which the latch x forms the armature. *
Auxiliary bells L may be erected in any desired places and caused to operate by
the spring contact N" and the local battery M, as soon as the striking mechanism
is set in operation.
According to the second construction shown in Figures 5 and 6 the making of
the electrical contacts by the barometer takes place in a similar manner to that just
described only in a more simple manner: The fork is divided into two parts by
insulating material and the hand Z is insulated from the arbor upon which it is
mounted, whereby the closing of the circuit 1-2 is only possible when the
barometer is falling and the closing of the circuit 1-3 only when the barometer'
is rising; the spring contact N¹ before described is then rendered unnecessary.
When the barometer is falling the lever H is operated once at every millimetre
of movement of the barometer by the closing of the circuit 1-2 and the energizing
of the electromagnet m, thereby causing the ratchet wheel D and the stepped snail
wheel A to advance one tooth and one step. respectively. With the stepped snail
wheel A is connected ordinary repeater striking mechanism. The ratchet wheel D
and the stepped wheel A have however 11 teeth or steps respectively, and the first
step of the stepped wheel is so high that with this step a disconnection of the
striking mechanism does not take place at all, accordingly the striking mechanism
does not operate when the barometer is rising. The next step which corresponds
with a fall of one millimetre gives one stroke per minute.

page_text: Y
When the barometer is rising, the electromagnet m¹ is energized in consequence
of the closing of the circuit 1-3 whereby the stop lever or pawl S is attracted,
and the ratchet wheel D together with the stepped snail wheel A are disconnected
and brought back, to their original positions.
The disconnection of the striking mechanism after a definite period of time
(say 8 hours) takes place in quite a different manner from that described in the
first construction.
The device P is similar to that in Hipp's chronoscope. The movable spindle n
carries Hipp's needle o, a cord pulleys and a disc t. The disc t has a tappet u
which, at each complete revolution, makes a momentary contact with a contact
piece v, thereby closing the circuit 4-5. The current of this circuit flows also
around the electromagnet m². The disc p which is provided with radial teeth is
caused to revolve once in eight hours by a wheel r of the clock mechanism.
Whenever the ratchet wheel D is moved forward one tooth, it forces the lever S
back, so that the latter presses the movable spindle n to the right. The needle o is
thereby shifted from between the teeth of the disc p, and the disc t is turned by
the weight G into its original position as shown. As soon as the tooth of the
ratched wheel has passed, the spring F forces the movable spindle n back, the
needle o enters between two teeth of the wheel p and the spindle n is now rotated
by the clockwork; until, after a lapse of 8 hours, the contact u-v takes place,
whereby through the closing of the circuit 4-5 the needle is again shifted and the
disc t again moves into its original position.
When the barometer is rising the closing of the circuit 1-3 performs the same
operation.
Now if within 8 hours after a fall of one millimetre of the barometer a second
fall of one millimetre occurs, the disc t passes to its original position and the
striking mechanism now gives a double signal for 8 hours, if during this time no
fall or rise of the barometer has taken place.
This somewhat modified manner of signalling has the result that after a fall of
several millimetres, the bell signals cease simultaneously 8 hours after the last
millimetre falls, which for the purpose of giving warning is in no way a dis-
advantage in the working of mines.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is
First. The combination with a barometer, of an electric contact device, which
actuates by suitable means the stepped disc of striking mechanism or an electric
bell in any suitable manner, for the purpose specified.
Second. Actuating the stepped disc or snail wheel of striking mechanism, in
such a manner that after a certain period of time, say for instance 8 hours, the said
dise or snail can be returned to its normal position, for the purpose specified.
Third. The opening of a second passage for the electric current when the air
pressure increases and the barometer rises, which current acts in connection with
suitable mechanism in such a manner as to bring the signalling devices to their
original positions, for the purposes specified.
: