Improvements in Alarm-gauges for Steam Boilers.
Year: 1895

page_text: Date of Application, 15th Mar., 1895
Complete Specification Left, 27th May, 1895-Accepted, 6th July, 1895
[Communicated from abroad by FREDERICK DEVEREUX KLAPP, of Jamestown,
Dakota, United States of America, Bank Manager.]
Improvements in Alarm-gauges for Steam Boilers.
I, ANNIE CATHERINE SUSANNAH BRUNETTA LESLIE, of Buckingham Palace
Hotel, Buckingham Gate, Housekeeper, do hereby declare the nature of this
invention to be as follows:-
The object of this invention is to provide a new and improved boiler alarm-gauge,
which comparatively simple and durable in construction, and which is arrange!
to accurately indicate both the steam pressure and the degree of heat in the boiler,
so as to enable the attendant to see at a glance, whether the boiler is in a safe
condition or not.
The invention consists principally of a heat indicator and a pressure indicator,
both arranged in such a manner that the hand or pointer of the heat indicator
moves in unison with the pointer of the pressure gauge, as long as the boiler is
working under normal conditions, the said heat indicator hand travelling faster
than the pressure gauge hand whenever there is an abnormal increase of heat in
the boiler.
The invention also consists of certain parts and details, and combinations of the
same, as will be hereinafter described.
As is well known, the steam pressure and the temperature in the boiler have a
uniform and proper ratio, so that on an increase of boiler pressure an increase of
temperature takes place as long as the boiler is in proper condition. The boiler is
in the said condition whenever it contains a sufficient amount of water to cover
parts exposed to heat, the water having the necessary amount of air at least one
cubic inch in one hundred cubic inches of water at 60° Fahrenheit, and the boiler
being built sufficiently strong.
A boiler is in a dangerous condition when it does not have a sufficient amount of
water to cover the parts exposed to heat, when the air is almost completely boiled
cut of the water, and when the boiler is not strong enough to hold the working
pressure. A boiler being in this dangerous condition is liable to explode at any
time. Now, with my invention hereinafter more fully described in detail,
I indicate the condition of the boiler, that is, whether it is in a safe or unsafe
condition.
It is further a well known fact that the heat generated in the fire box of a steam
boiler is for the purpose of raising the temperature of water to its boiling point,
and the rise of pressure in the boiler elevates the boiling point while a reduction
of pressure lowers the boiling point. Now, if a boiler is fired up without any
water over the crown sheet, then the temperature rises and by my invention an
alarm is sounded as hereinafter more fully described.
If the air is boiled out of the water, then the boiling will stop, the water will
then get superheated, and the boiler will explode if only 25° hotter than it should
be under pressure.
The boiler will explode if the pump or injector is applied to
refill the boiler or if the engine is reversed, causing the pistons to pump air into
the boiler. The water which passes through the pump or the injector contains
according to its density about three cubic inches of air in one hundred cubic inches
of water, and as soon as that water enters the boiler, the air is mixed with and

page_text: absorbed. by the superheated water; so as to cause the volume of superheated water
to boil at 25° lower temperature, thereby causing the boiler to explode.
If air is pumped into the boiler, as in the case of reversing the engine, the
momentum of the moving parts of the engine overcomes the boiler pressure and air
is forced into the boiler through the throttle, thus causing an explosion in an
instant, if the water is superheated. Further if the water is only superheated 20º,
and the steam pressure reduced five pounds, as by opening the throttle valve to
start the engine, then the reduction of pressure causes the water to boil at 5° or 6°
lower temperature, which has the same effect as superheating the water 25°. If
the pressure is reduced in a boiler suddenly;.as in blowing out.safety or whistle
valves, this reduces or lowers the temperature: of the water so as to cause an
explosion. By continual boiling, parts of the oxygen that water naturally contains
enters into combustion. with the iron, so as to form an oxide of iron, while the
other parts of oxygen with the nitrogen are mixed with the steam and exhausted
into the atmosphere. Now, by the improvement presently to be described, all
these abnormal conditions of the boiler are at once indicated and an alarm is
sounded, so that the attendant can apply the proper remedy to avoid' or prevent an
explosion..
The improved alarm: gauge according to this.invention consists principally of a
heat indicator or heat indicator and a steam pressure indicator, both working in
unison as long as the conditions in the boiler are normal, but as soon as an abnormal
heat is produced in the boiler, then the thermostat actuates an alarm and at the
same-time indicates the degree of temperature within the boiler.
The device is applied, to a boiler of any approved construction, having in its
front or head plate a bushing carrying on its inner end a pipe extending within the
boiler and a short distance above the crown sheet of the said boiler. On the inner
end of the said pipe is secured a cap containing the head of a rod extending loosely
through the pipe and into a casing provided with a neck secured in the outer end
of the bushing aforesaid. The outer end of the rod carries a metallic head provided
with another rod supporting a plate pivotally connected with the short arm of a
bell-crank lever fulcrumed within the casing. By the arrangement of the said
metallio head, its rod may be adjusted relative to the bell-crank lever, so as to
properly set the apparatus. It is understood that the first named rod is preferably
made of glass, but any other suitable material may be employed that expands and
contracts less than the pipe that surrounds it, and likewise the said pipe can be
made of any material that will expand and contract more than the contained rod.
On the free end of the long arm of the said bell-crank lever rests the head of a
screw screwing in the lower end of a vertically-disposed rod extending loosely
through a pipe secured on the casing aforesaid external to the boiler and connected
with the indicator casing which is preferably supported by a bracket on the boiler.
Now, it will be seen that by an increase of temperature within the boiler; the
internal pipe will expand so that its cap in moving inwardly, pulls on the head of
the contained rod made of glass or other non-conductor of heat, whereby the outer
end of the said rod exerts a pull on the short arm of the bell-crank lever to impart
a swinging motion to the latter so as to lift the rod resting them, it being
understood that the distance the rod. is lifted. is in proportion to the expansion of
the pipe within the boiler. The upper end of this rod supports a rack, the teeth
of which are in mesh. with a pinion secured on a transversely-extending. shaft
mounted to turn. in suitable bearings in a frame secured within the indicator casing.
On the outer end of this shaft is fastened a hand or pointer indicating on a scale
representing degrees and sub-divisions of heat and formed on a dial secured within
the indicator casing in the rear of the glass frout of the said casing. On the rear
end of the said transversely-extending shaft is fastened the inner end of a coil
spring attached with its outer end to the frame secured within the indicator casing,
so that the heat indicator hand. is kept steady and prevented from vibrating.
Now, it is understood that when the rod is lifted on an increase of temperature in.
the boiler, then its rack. engaging the pinion turns the latter and consequently the

page_text: shaft, so that the pointer is carried forward by the movement of the shaft 'to
indicate the degree of heat within the 'boiler, on the graduation of the dial. On
the same dial is indicated the pressure of the steam in the boiler, and for this
purpose I provide a hub through which passes the shaft aforesaid and which
carries a pinion in mesh with a rack having a vertical movement according to the
increase or decrease of the boiler pressure, as hereinafter more fully described. 'On
the front end of this hub is secured a hand or pointer directly in the rear of the
heat indicating pointer and indicating on a graduation formed on the dial, the said
graduation representing pounds and sub-divisions of steam pressure. The two
graduations for heat and pressure are arranged in such a manner that the
corresponding pounds and degrees are those of the steam pressure in the boiler and
the heat contained therein, under normal conditions of the 'boiler-that is to say,
for example when the pressure within the 'boiler is eighty pounds 'then the
temperature therein is 277°, the said 80 pounds and 277° being arranged directly
along-side each other on the graduations.
In order to return the pressure pointer or hand whenever the pressure decreases
in the boiler, I provide a coil spring connected at its inner end with the hub
aforesaid and fastened at its outer end to a part of the frame. 'On 'the lower end
of the pressure rack before mentioned is secured a pin resting on the free end of a
lever pivoted to a second lever 'fulcrumed on a fixed bracket. The free end of the
last-named lever carries a vertically-disposed screw engaging the underside of the
lever resting thereon so that the said two levers can be adjusted relatively to each
other by screwing the said set screw either upward or downward. The lower
lever between its fulerum point and the fulcrum for the upper lever is connected by
a fixed link with a third lever fulcrumed to a fixed bracket. This third lever
rests on the upper end of a pin fitted to slide in the top of the diaphragın casing
and rests with its head on a diaphragm secured within the casing. A pipe connects
with the steam compartment of the boiler and with the space under the said
diaphragm, so that the diaphragm is subjected to the pressure of the steam within
the boiler. A valve is preferably arranged in the said pipe to shut off the steam
pressure from the diaphragm whenever desired. Now, it will be seen that the
steam pressure on the diaphragm moves the latter so that the pin 'resting 'thereon
actuates the levers aforesaid whereby the rack is caused to slide up or down
according to the increase of the pressure in the boiler 'or a decrease. 'This
movement of the rack causes a rotating of the pinion in mesh therewith, and its
hub, whereby the pointer or hand is moved on the graduation to indicate the
boiler pressure. Now, as long as the boiler is in a normal condition the two hands
will move together, 'the one indicating the temperature in the 'boiler, and the other
the pressure therein. On the pressure rack aforesaid is pivoted a lever formed
with a longitudinally-extending slot through which passes a screw screwing in the
other or temperature rack, so that the slotted lever is carried upwardly or
downwardly on the simultaneous movement of the said racks, as long as 'the boiler
is in a normal condition, but when the 'temperature in the boiler increases
abnormally and the temperature rack moves up faster than the pressure rack as
before explained, then a swinging motion is given to the said slotted lever by the
action of the temperature rack.
On the free end of the slotted lever is held a spring plate engaging normally.at
its outer end an insulated plate in which are arranged a number of contact points
so that on the swinging motion of the said slotted lever, the free end of the spring
plate will move in contact successively with the contact pins. The said insulated
plate, and the contact pins are held on an arm secured to and moving with an arm
extending from the temperature rack so that when the spring plate has finally
passed the uppermost contact pin it finally passes on to the arm on which the
contact pins are held so as to make a continuous connection with the latter. The
said arm is connected by a wire with a binding post held in the wall of the casing
and the said binding post is connected by a wire with one pole of a battery of any
approved construction. This battery is connected at its other pole with a wire

page_text: leading to a second binding post likewise held in the wall of the casing and this
binding post is connected inside of the casing with a wire leading to an electro
magnet arranged within the casing. The armature lever for this electro magnet
carries at its upper end a striker extending through the wall of the casing to act on
a bell supported from the said casing. Thus, when an electric current passes
through the said electro magnet, the armature lever is attracted and the striker
sounds the bell. The armature lever is provided near its free end with a spring
plate normally in contact with a contact point made in the shape of an arm and
connected by a wire with a binding post secured on the slotted lever previously
mentioned.
In order to adjust the arm carrying the said contact point relatively to the spring
plate, I fasten the said contact point on a transversely-extending shaft, journalled
in suitable bearings arranged on the frame. On the front end of this shaft is
secured a crank disk connected at its wrist pin with an arm formed at its rear end
with a longitudinally-extending slot engaged by a screw screwing in the frame.
Now, by loosening the screw the arm can be shifted so as to turn the shaft
connected thereto and consequently impart a swinging motion to the arm carrying
the contact point to adjust the latter relatively to the spring plate so as to make
the proper connection with the latter. After the adjustment is made, the screw is
screwed up so as to securely fasten the arm in place, thereby securely holding the
contact point in proper position relatively to the spring plate. The armature
lever is connected by a wire with a second electro magnet also adapted to attract
the armature lever whenever the temperature in the boiler rises abnormally, so as to
sound an alarm on the bell at the time the said abnormal rise of temperature in the
boiler takes place.
Now, it will be seen that if the boiler is fired up and without any water over
the crown sheet, then the temperature will increase abnormally within the boiler
and consequently the thermostat will act independently of the steam indicator, so
that the temperature rack will move upward faster than the pressure rack and
consequently a swinging motion is imparted to the slotted lever. At the same time
the heat indicating pointer will move in advance of the pressure pointer actuated by
the steam pressure indicator. The swinging motion imparted to the slotted lever
causes the spring plate to make connection with the next uppermost contact pin so
that the circuit is closed and an alarm is sounded by the striker on the bell. A
first call is thus sounded, and the circuit is again broken as soon as the spring
plate on the upward swinging motion of the slotted lever leaves the contact pin to
pass on to the insulated plate, and then on the further upward movement of the
slotted lever to pass to the next following contact pin to again complete the circuit
and make a second call and so on until finally the spring plate passes on to the arm
so as to ring the alarm continuously, the spring plate then remaining in contact
with the said arm on any further upward movement of the slotted lever until
further upward swinging motion of the said lever is arrested by the heat indicating
pointer having made a complete revolution and stops in contact with the pin
corresponding to about 800° of heat.
It will be seen that the.above mentioned circuit is completed whenever water is
superheated only 5°, as the spring plate will then make connection with the first
contact pin to sound the first call and so on. If the pressure is reduced in the
boiler suddenly, as by blowing out the safety valve or otherwise, then the pressure
rack will slide downward faster than the temperature rack so that again a
swinging motion is given to the slotted lever and consequently the spring plate
will again move in contact with the contact points to sound successively first,
second, third and continuous calls in the manner above described. Thus, it will be
seen that any abnormal condition of the boiler will cause a swinging movement of
the slotted lever, either by the temperature rack or by the pressure rack, so that
an alarm is sounded in the manner above described.
The spring plate moves upward only when steam pressure is reduced, and heat
not withdrawn from the water, or when the temperature is increased, and steam

page_text: pressure remains the same, at the same time completing a circuit which gives the
alarm. When water is foaming within a boiler the foam with the water often
falls below the crown sheet, when steam is shut off; the intense heat within the
fire box softens the parts not covered by water, and as a result the steam pressure
within the boiler caves or bulges in the side sheets, or the crown plate. With
this boiler alarm-gauge all this is prevented because when the water or foam
leaves the crown sheet, the iron pipe which composes part of the indicator is
surrounded by steam, and steam being hotter than water will instantly turn the heat
pointer ahead of the steam pointer, and give an alarm in time to prevent the sheets
from caving in.
Dated this 15th day of March 1805
I, ANNIE CATHERINE SUSANNAH BRUNETTA LESLIE, of Buckingham
Palace Hotel, Buckingham Gate, in the County of Middlesex, House Keeper,
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 :-
The object of this invention is to provide a new and improved boiler alarm-
gauge, which is comparatively simple and durable in construction, and which is
arranged to accurately indicate both the steam pressure and the temperature in
the boiler, so as to enable the attendant to see at a glance, whether the boiler is in
a safe condition or not.
1
The invention comprises a temperature, indicator and a pressure indicator, so
arranged that the hand or pointer of the temperature indicator moves in unison
with the pointer of the pressure gauge, as long as the boiler is working under
normal conditions, but travels faster than the pressure gauge hand whenever there
is an abnormal increase of temperature in the boiler.
The invention also comprises certain parts and details, and combinations of the
same, as will be hereinafter described.
It is well known that the steam pressure and the temperature in the boiler have
a fixed relation the one to the other so that an increase of temperature is followed
by an increase of pressure as long as the boiler is in proper condition. The boiler
is in such condition whenever it contains a sufficient amount of water to cover
parts exposed to heat, when the water contains the necessary amount of air (at
least one cubic inch in one hundred cubic inches of water at 60° Fahrenheit) and
when the boiler is built sufficiently strong.
A boiler is in a dangerous condition when the water is insufficient to cover the
parts exposed to heat, when the air is almost completely boiled out of the water,
and when the boiler is not strong enough. A boiler in this dangerous condition
is liable to explode at any time. Now, with my invention hereinafter more
fully described in detail, I indicate whether the boiler is in a safe or unsafe
condition.
Further it is well known that a rise of pressure in the boiler elevates the boiling
point while a reduction of pressure lowers the boiling point. Now, if a boiler
fitted with my improved alarm gauge is fired without any water over the crown
sheet, the temperature rises and an alarm is sounded as hereinafter more fully
described.
If the air is boiled out of water, then the boiling will stop, the water will
become superheated, and the boiler will be in danger of explosion if only 25°

page_text: hotter than it should be under pressure. The boiler will also be in danger of
explosion if the pump or injector is applied to pump water into the boiler or if
the engine, being reversed, causes the pistons to pump air into the boiler. The
water which passes through the pump or the injector contains according to its
density about three cubic inches of air in one hundred cublic inches of water, and
as soon as that water enters the boiler, the air is mixed with and absorbed by the
superheated water, so as to cause the latter to boil at :25° lower temperature,
whereupon the pressure is immediately raised to a dangerous point and explosion
may occur.
If air is pumped into the boiler, as in the case of reversing the engine, the
momentum of the moving parts of the engine overcomes the boiler pressure and
air is forced into the boiler through the dry pipe or throttle valve, thus causing an
explosion in an instant, if the water is superheated. Further if the water is only
superheated 20°, and the steam pressure reduced five pounds, as by opening the
throttle valve to start the engine, then the reduction of pressure causes the
water to boil at 5° or 6° lower temperature, which has the same effect as
superheating the water 25°. If the pressure in a boiler is suddenly reduced as for
example might occur when the safety or whistle valves are blown out, this reduces
or lowers the temperature of the water so as to cause an explosion. By the
continual boiling, some of the oxygen that water naturally contains combines with
the iron to form an oxide of iron, and some of the oxygen together with the
nitrogen is mixed with the steam and exhausted into the atmosphere. Now, by the
improvement presently to be described, all these abnormal conditions of the boiler
are at once indicated and an alarm is sounded, so that the attendant can apply the
proper remedy to avoid or prevent an explosion.
The improved alarm-gauge constructed according to this invention consists
principally of a temperature indicator or a temperature indicator and a steam
pressure indicator both working in unison as long as the conditions in the boiler
are normal, but as soon as an abnormal temperature exists in the boiler, the
temperature indicator actuates an alarm and at the same time indicates the
temperature.
Referring to the accompanying drawings,
Figure 1 is a side elevation partly in section of the apparatus applied to a
boiler.
Figure 2 is an enlarged transverse section of the gauge proper taken on the
line 2-2 of Figure 3; and
Figure 3 is a sectional elevation of the same on the line 3-3 of Figure.2.
The device, as shown in the drawings, is applied to a boiler A of any approved
construction, having in its front or head plate A' a bushing B carrying on its inner
end a pipe B extending within the boiler A and a short distance above the crown
sheet A of the boiler. On the inner end of the pipe B' is secured a cap B³
containing the head C₁ of a rod C extending loosely through the pipe B¹ and into
a casing D provided with a neck -D' secured in the outer end of the bushing .B by
means of a set screw D2 as plainly shown in Figure 1. The outer end of the rod C
carries a metallic head E provided with a rod E¹ supporting a plate E² pivotally
connected with the short ärm F1 of a bell-crank lever F fulcrumed at F within
the casing D. By the arrangement of the head E, the rod may be adjusted
relatively to the bell-crank lever F, so as to properly set the apparatus. The
rod C is preferably made of glass, but any other suitable material may be
employed that expands and contracts less than the pipe B', which is made of any
suitable material that will expand and contract more than the rod C. On the free
end of the long arm of the said bell-crank lever F rests the head of a screw G¹
screwing in the lower end of a vertically-disposed rod G extending loosely through
a pipe D³ secured on the casing D and connected with the indicator casing H
which is preferably supported by a bracket H¹ from the boiler. Now, it will be
seen that by an increase of temperature within the boiler A, the pipe B' will
expand so that the cap B2 of the said pipe in moving inwardly, pulls on the

page_text: K
head C¹ of the rod C made of glass or other non-conductor of heat,, whereby
the outer end of the said rod moves the head E to the left, whereby a pull: is
exerted on the. short arm of the bell-crank lever F and a swinging motion is.
imparted to the latter in the direction of the arrow a' so as to lift the rod G ;:
it will be understood that the distance the rod is lifted is in proportion to the
expansion of the pipe B' within the boiler A. The upper end of this rod G.
supports a rack I Figures 2 and 3, the teeth 1' of which are in mesh with a
pinion J Figure 2 secured on a transversely-extending shaft J mounted to turn
in suitable bearings in a frame. H² secured within the casing H. On the outer-
end of this shaft J is fastened a hand or pointer J2 indicating on a scale K¹
representing degrees and fractions of degrees and formed on
a: dial
secured within the casing Hin the rear of the glass front H³:
(Figure 2) of the said casing. On the rear end of the shaft J. is fastened
the inner end of a coil spring J³. The outer end of the said spring is attached
to the frame H2 so that the temperature indicator hand is kept steady and
prevented from vibrating. Now, it is understood that when the rod G is lifted
owing to an increase of temperature in the boiler A, then its rack I engaging.
with the pinion J' turns the latter and consequently the shaft J, so that the
pointer J is carried forward by the movement of the shaft to indicate the
temperature within the boiler, on the scale K of the dial K. On the same dial K.
is indicated the pressure of the steam in the boiler, and for this purpose I provide
a bub L through which passes the shaft J and which carries a pinion L'in mesh
with a rack N having a vertical movement according to the increase or decrease
of the boiler pressure, as hereinafter more fully described. On the front end of
this hub L is secured a hand or pointer L2 directly in the rear of the pointer Ja
and indicating on a graduated scale K2 formed on the dial K, the said scale K²
representing pounds and sub-divisions of pounds of steam pressure. The two
scales K and K2 are arranged in such a manner that the corresponding pounds
and degrees are those of the steam pressure in the boiler and the temperature
therein, under normal conditions of the boiler-that is to say, when the pressure
within the boiler is eighty pounds for example then the temperature therein is 277°,
the said 80 pounds and 277° being arranged directly along-side each other on the
scales K and K².
In order to return the pointer or hand L2 whenever the pressure decreases in
the boiler, I provide a coil spring L³ connected at its inner end to the said hub L,
and fastened at its outer end to a part of the frame H2. On the lower end of the
rack N is secured a pin N¹ resting on the free end of a lever N2 pivoted at N³ to
a lever O fulcrumed at O' on a bracket attached to the top of the diaphragın.
casing P arranged within the casing H. The free end of the lever O carries a
vertically-disposed screw 02 engaging with the underside of the lever N2 so that
the said two levers N2 and O can be adjusted relatively to each other by screwing
the said set screw 02 either upward or downward. The lever O at a point between
its fulcrum O' and the fulcrum N³ for the lever N2 is connected by a link O³ with
a lever O fulcrumed at 0° to a bracket on the casing P. This lever 04 rests on
the upper end of a pin P¹ fitted to slide in the top of the casing P and resting.
with its head on a diaphragm P2 secured within the casing P. A pipe P³ connects
with the steam compartment of the boiler A and with the underside of the said
diaphragm P2, so that the latter is subjected to the pressure of the steam within.
the boiler A. A tap P is preferably arranged in the pipe P³ to shut off the
steam pressure from the diaphragm whenever desired. Now, it will be seen that
the steam pressure on the diaphragm P2 deflects the latter so that the pin P¹
actuates the lever O* which, by the link O³ controls the lever O and consequently
the lever N2, whereby the free end of the lever in pressing on the pin N of the
rack N causes the latter to slide up or down according to the increase or decrease
of the pressure in the boiler. This movement of the rack N produces a rotation
of the pinion L', and its hub L, whereby the pointer or hand L2 is moved over

page_text: the scale K2 to indicate the boiler pressure. Now, as long as the boiler is in a
normal condition the two hands J2 and L2 will move together, the one indicating
the temperature in the boiler, and the other the pressure therein. On the rack N
is pivoted at Q¹ a lever Q formed with a longitudinally-extending slot Q2 through
which passes a screw Q3 screwing in the other rack I, so that the lever Q is carried
upwardly or downwardly on the simultaneous movement of the said racks N and I,
as long as the boiler is in a normal condition, but when the temperature in the
boiler increases abnormally and the said rack I moves up faster than the rack N,
as before explained, then a swinging motion is given to the said lever by the
action of the rack I.
On the free end of the lever Q is held a spring plate Qengaging normally at
its outer end with an insulated plate R in which are arranged a number of contact
points R' so that on the swinging motion of the said lever Q, the free end of the
spring plate Q will move in contact successively with the contact pins R'. The
said insulated plate R, and the contact pins R' are held on an arm R2 secured to
and moving with an arm 12 extending from the rack I so that when the spring
plate Q has passed the uppermost contact pin R¹ it finally passes on to the arm R²
so as to make a continuous connection with the latter. The arm R2 is connected
by a wire S with a binding post S¹ held in the wall of the casing H and the said
binding post S is connected by a wire S2 with one pole of the battery S³ of any
approved construction, and as plainly shown in Figure 1. The other pole of this
battery S3 is connected with wire leading to a second binding post S likewise
held in the wall of the casing H and connected inside of the casing H with a
wire S leading to an electro magnet T arranged within the casing H. The
armature lever T¹ for this electro magnet T carries at its upper end a striker T
extending through the wall of the casing H to act on a bell T3 supported from
the said casing H. Thus, when an electric current passes through the said electro
magnet T, the armature lever T¹ is attracted and the striker T2 sounds the bell T³.
The armature lever T¹ is provided near its free end with a spring plate T
normally in contact with a contact point U made in the shape of an arm and
connected by a wire U¹ with a binding post Q' secured on the lever Q previously
mentioned.
In order to adjust the arm carrying the contact point U relatively to the spring
plate T, I fasten the said contact point U on a transversely-extending shaft U2,
see Figure 2, journalled in suitable bearings arranged on the frame H2. On the
front end of this shaft U2 is secured a crank disc U³ connected by its wrist pin
with one end of an arm U having at its other end a longitudinally-extending
slot U engaged by a screw U screwing in the frame H2, see Figure 3. Now, by
loosening the screw U, the arm U can be shifted from the left to the right or
the right to the left, so as to turn the shaft U2, and consequently impart a
swinging motion to the arm carrying the contact point U, to adjust the latter
relatively to the spring plate T₁ so as to make the proper connection with the
latter. After the adjustment is made, the screw U is screwed up to securely
fasten the arm U in place, so as to securely hold the point U in proper position
relatively to the spring plate T¹. The armature lever T' is connected by a
wire T with a second electro magnet Te also adapted to attract the armature
lever T¹ whenever the temperature in the boiler rises abnormally, so as to sound
an alarm on the bell T3 at the time the said abnormal rise of temperature in the
boiler takes place.
Now, it will be seen that if the boiler A is fired up and without any water
over the crown sheet A², the temperature will increase abnormally within the
boiler and consequently the temperature indicator will act independently of the
steam indicator, so that the rack I will move upward faster than the rack N and
consequently a swinging motion will be imparted to the lever Q. At the same
time the pointer J2 will move in advance of the pointer L² actuated by the steam
pressure indicator. The swinging motion imparted to the lever Q causes the

page_text: spring plate Q to make connection with the next uppermost contact pin R¹ and
thereby to close the circuit between the wires U₁ and S, by way of the contact U.
electro magnet T, wire T and armature T¹ connected by electro magnet T and
wires S and S with the battery S³ to which leads the wire S connected with the
previously mentioned wire S. Thus, an alarm is sounded by the striker T' on the
bell T. A first call is thus sounded, and the circuit is again broken as soon as.
the spring plate Q on the upward swinging motion of the lever Q leaves the
contact pin R' to pass on to the insulated plate R, and then on the further upward
movement of the lever Q to pass to the next following contact pin R' to again
complete the circuit and make a second call and so on until finally the spring
plate Q passes on to the arm R' whereupon it rings the alarm continuously, the
spring plate Q then remaining in contact with the said arm R2 on any further
upward movement of the lever Q, until further upward swinging motion of the
said lever is arrested by the pointer J2 which after having made a complete
revolution is stopped by contact with the pin K* fixed in the position corresponding
to a temperature of about 800°.
It will be seen that the above mentioned circuit is completed whenever water
is superheated only 5º, as the spring plate Q will then make connection with
the first contact pin R₁ to sound the first call and so on.
If the pressure is
reduced in the boiler suddenly, as by the blowing out of the safety valve or other
device, the rack N will slide downward faster than the rack I so that again a
swinging motion is given to the lever Q and consequently the spring plate Q will
again move in contact with the contact points R₁ to sound successively first,
second, third and continuous calls in the manner above described. Thus, it will
be seen that any abnormal condition of the boiler will cause a swinging movement
of the lever Q, either by the rack I or by the rack N, so that an alarm is sounded
in the manner above described.
The spring plate Qmoves upward only when steam pressure is reduced, and
heat is not abstracted from the water, or when the temperature is increased, and
steam pressure remains the same, at the same time completing an electric circuit
which gives the alarm. When water is foaming within the boiler the foam with
the water often falls below the crown sheet, when steam is shut off; the intense'
heat within the fire box softens the parts not covered by water, and as a result the
steam pressure within the boiler caves or bulges in the side sheets, or the crown.
plate. With the above described boiler alarm-gauge all this is prevented because
when the water or foam leaves the crown sheet, the iron pipe which composes
part of the indicator is surrounded by steam, and steam being hotter than water
will instantly cause the temperature pointer to move ahead of the steam pressure
pointer, and give an alarm in time to prevent the sheets from caving in.
Having now particularly described and ascertained the nature of the said inven-
tion 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 :-
1. A boiler alarm-gauge, comprising a temperature indicator and a pressure
indicator, operating in unison as long as the boiler is in a normal condition, and
operating differentially when the boiler is in an abnormal condition, substantially
as described.
2. The aforesaid boiler alarm-gauge arranged in such a manner that the hand
of the temperature indicator moves in unison with the hand of the pressure
indicator as long as the boiler is working under normal conditions, but the said
hands move at a different rate when the boiler is working under abnormal conditions,
substantially as described, for the purpose specified.
3. A boiler alarm-gauge, comprising a temperature indicator and a pressure
indicator, each provided with a rack, a lever pivoted on one of the racks and
engaged by the other rack, and an electric alarm of which the said lever forms
the circuit closer, all so arranged that the said lever receives a swinging motion
B

page_text: whenever the racks move at a differential rate of speed, substantially as shown
and described for the purpose specified.
4. In a boiler alarm-gauge, the combination with two movable racks, of which
one is controlled by a pressure indicator and the other by a temperature indicator,
of two hands actuated from the said racks, a dial graduated with a temperature
scale and with a pressure scale, a lever pivoted on one of the said racks and
engaged by the other rack, and an electric alarm of which the said lever forms a
circuit closer, substantially as shown and described.
5. In a boiler alarm-gauge, the combination of two racks controlled by a pressure
indicator and a temperature indicator, a lever pivoted on one of the said racks
and engaged by the other rack, so that when the said racks move at a differential
rate of speed a swinging motion is given to the said lever, and an electric alarm,
of which the said lever forms the circuit closer, substantially as shown and
described.
6. In the apparatus referred to in the preceding claim an arm provided with au
insulated plate through which extend contact pins arranged on the said arm, which
pins are adapted to be engaged by a spring plate on the free end of the swinging
lever or to be otherwise engaged by the said lever, and an electric alarm connected
by one wire with the said lever and by its other wire with the said arm, substantially
as shown and described.
7. A boiler alarm-gauge provided with a temperature indicator, comprising a
pipe adapted to be secured to the boiler and extending over the crown plate, the
inner end of the said pipe being provided with a cap, a non-conducting rod held
loosely in the said pipe and provided with a head inclosed by the said cap beyond
the end of said pipe and of greater diameter than the pipe so that an expansion
of the said pipe draws the said rod inwardly, and a bell-crank lever connected
with the outer end of the said rod, with or without an adjusting mechanism
between the said rod and the said bell-crank lever, substantially as shown and
described and for the purpose specified.
8. The combination, with the parts mentioned in the preceding claim, of a
vertically disposed rod resting on the free end of the bell-crank lever, a rack
carried by the said vertical rod, a pinion in mesh with the said rack, a shaft
carrying the said pinion, and a hand or a pointer on the said shaft, substantially as
shown and described.
Dated his 2nd 1...
M
1005
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.