IMPROVEMENTS IN APPARATUS FOR REGULATING THE TEMPERATURE OF STOVES AND FURNACES, AND OF WATER, AIR, OR OTHER FLUIDS CONTAINED IN VESSELS OR CHAM- BERS, THE STRENGTH OF SPIRITUOUS LIQUORS AND OF CHEMICAL MIX- TURES, AND THE HYGROMETRIC STATE OF THE AIR IN BUILDINGS, Rooms, &c
Year: 1853

page_text: Application of the Electric Current to Apparatus
for Indicating and Regulating the Temperature
of Air, Water, and other Fluids, the Strength
LETTERS PATENT to Henry Kraut, of Zurich, in Switzerland
Engineer, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
REGULATING THE TEMPERATURE OF STOVES AND FURNACES, AND OF
WATER, AIR, OR OTHER FLUIDS CONTAINED IN VESSELS OR CHAM-
BERS, THE STRENGTH OF SPIRITUOUS LIQUORS AND OF CHEMICAL MIX-
TURES, AND THE HYGROMETRIC STATE OF THE AIR IN BUILDINGS,
Rooms, &c."
PROVISIONAL SPECIFICATION left by the said Henry Kraut at
the Office of the Commissioners of Patents, with his Petition, on
the 24th October 1853.
I, HENRY KRAUT, of Zurich, in Switzerland, Engineer do hereby
5 declare the nature of the said Invention for "IMPROVEMENTS IN APPA-
RATUS FOR REGULATING THE TEMPERATURE OF STOVES AND FURNACES, AND
OF WATER, AIR OR OTHER FLUIDS CONTAINED IN VESSELS OR CHAMBERS,
23349.

page_text: THE STRENGTH OF SPIRITUOUS LIQUORS AND OF CHEMICAL MIXTURES; AND
THE HYGROMETRIC STATE OF THE AIR IN BUILDINGS, Rooms &c." to be
as follows:
It consists, First in regard to the regulating of the temperature of
stoves and furnaces, and of water, air or other fluids in vessels or cham-
bers: In an apparatus which I call a "thermostator," whose operation
is based upon the principle of the expansion of metals, when heated; and
by means of which an electric current is established, acting upon an
electro-magnet, which produces a power whereof I avail myself for
effecting the opening or closing of dampers, ventilators, valves, cocks,
and other similar mechanism. The establishing of an electric current
can be effected in various ways namly a) by adjusting the two
extremities of the wires connected with the battery, forming the poles,
and being placed opposite to each other, in such a manner, that they will,
by their expansion, come in contact with each other, so soon as the stove,
furnace, or fluid shall have attained a certain desired temperature.
6) By uniting the two poles through the medium of a third metallic
body which, on expanding, comes in contact with the two poles; and
c.) By bringing either of the two poles in contact with a third metallic
body, consisting of two pieces of metal of unequal expansion, soldered or
otherwise joined together, one end of which is fixed to a plate; and
which will, according to the temperature, incline towards, and come in
contact with the one or the other of the wires forming the two poles,
and which may be attached to the same plate. The electric current
being thus established, the electro-magnetic power will, immediately, act
upon the dampers, ventilators, valves, cocks, or other similar mechanism,
by means of a suitable combination of levers, rods, &c. and either wholly
or partially close the same; and thus, by checking the draft in ovens or
furnaces, prevent the temperature from rising further; or the water, air,
or other fluids when used for baths, the ventilation and heating of
rooms, or other similar purposes, from attaining a higher degree of heat
than that required, by checking or stopping the ingress or egress thereof.
It is evident that as a very slight diminution of heat will sever the poles,
break, the electric current, and produce the reverse action upon the
dampers, cocks, or other similar mechanism, the temperature can be

page_text: regulated and maintained with the greatest precision. And it is equally
evident, that by adjusting the distance of the two poles from each other
in the apparatus described under the letter a) or by placing the poles
nearer to or further from the third metallic body in the apparatus
described under letters 6.) & c.) their contact can be effected sooner
or later, and therefore the degree of heat decreased or increased, and
afterwards maintained with the greatest precision; thereby not only
effecting a saving of fuel, but also greatly diminishing the chances of
accidents.
Secondly, as regards the regulating of the strength of spirituous
liquors and of chemical mixtures: I cause a float or gauge, placed in
the liquid to come in contact with one or both of the poles and thus to
establish the electric current; which, acting upon the electro-magnet,
will regulate the relative quantity of the liquids to be mixed (when
properly adjusted) by entirely or partly closing a cock, tap, or other
mechanism.
Thirdly as regards the regulation of the hygrometric state of the air
in buildings, rooms &c. I cause the action of the hygrometer to
bring the poles in contact, and thus regulate the admission of damp or
dry air by appropriate means. It is evident, that in every case the
opening or closing of the dampers, ventilators, valves, cocks and other
similar mechanism, may be effected either by the direct action or by the
interruption of the action of the electro-magnet. According to the pur-
poses for which my regulating apparatus is required, and according to
circumstances, I make use of one of the three following kinds of bat-
teries, namely 1st The thermo-electric battery which is composed of a
series of plates of two different kinds of metals soldered together; one
part of which is in contact with a medium of high, and the other with
a medium of low temperature, and which produces an electric current
of great intensity. This kind of battery I use in preference where my
apparatus is applied to furnaces for steam boilers. 2nd The rotary bat-
tery which I apply where driving power is at hand, and in the absence
of high temperature; and 3rd The common or constant battery.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Kraut in the Great Seal Patent Office on
the 24th April 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME; I
HENRY KRAUT of Zürich in Switzerland, Engineer send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Twenty-fourth day of October in the
year of our Lord, One thousand eight hundred and fifty-three in the
seventeenth year of Her reign, did for Herself, Her heirs and successors,
give and grant unto me the said Henry Kraut Her special licence that
I the said Henry Kraut, my executors, administrators and assigns, or
such others as I the said Henry Kraut, my executors, administrators
and assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain, and Ireland, the Channel Islands
and Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR
REGULATING THE TEMPERATURE OF STOVES AND FURNACES, AND OF WATER,
AIR, OR OTHER FLUIDS CONTAINED IN VESSELS OR CHAMBERS, THE STRENGTH
OF SPIRITUOUS LIQUORS, AND OF CHEMICAL MIXTURES, AND THE HYGRO-
METRIC STATE OF THE AIR IN BUILDINGS, ROOMS &c." upon the condition
(amongst others) that I the said Henry Kraut by an instrument in
writing under my hand and seal should particularly describe and ascer-
tain the nature of the said Invention and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent:
NOW KNOW YE, that I the said Henry Kraut do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement;
My Invention consists in the application of the electric current to
the regulating and maintaining the temperature of stoves and furnaces,
and of water, air, or other fluids contained in vessels or chambers the

page_text: strength of spirituous liquors, and of chemical mixtures, and the hygro-
metric state of the air in buildings, rooms &c., by causing the electric
current to open or close certain dampers, valves, slides, cocks, or other
similar mechanism, as circumstances may require, so as to admit or
exclude atmospheric air, and to interrupt and restore the flow of hot
or cold air, or water; of water and spirituous liquors, or of stronger and
weaker chemical ingredients, and of dry or moist air.
The electric current may be produced either by the thermo-electric
battery, by the rotary battery, or by the common or constant battery,
as may be found most economical, advantageous, and convenient in
each case.
In order that my Invention may be better understood I will proceed
to describe the same, reference being had to the accompanying Drawing
and to the letters and figures marked thereon.
As for the purpose of ensuring the efficient action of the magnets
which have to operate the opening and closing of the dampers, valves,
cocks, &c. it is absolutely necessary that each magnet should have to
lift its load through a very short space only, I make use of the arrange-
ment shewn in Fig. 1 of the accompanying Sheet of Drawings.
a, b, c, and d. are the electro-magnets, fixed in pairs to a piece of
wood or other non-conducting substance, e; the magnets b. and d. being
placed such a distance below the magnets a, and c, as to allow sufficient
play to the keepers a¹, b, c, and d³, the contiguous ends of which are
attached to the wire or chain f, which is connected with the damper,
valve, or cock to be opened or closed. The four magnets are connected
with each other by the wires g, and h. which unite them with the bat-
tery. The relative position of the keepers which are hinged at a b³. c³.
and respectively is such that when they are inactive the distances of
the keepers a¹ b¹. c. and d. will be as 1. 2. 3. and 4 from their respec-
Live magnets so that on the circuit being completed, each of the
keepers will be successively brought within the same range of its corre-
sponding magnet, and therefore be able to exert its power in the most
effective manner, until the whole lift is completed. It is evident that
by increasing the number of magnets, the lift might be increased to any
convenient extent, without rendering the apparatus less effective.

page_text: In Fig 1 the magnets are supposed to be connected with a damper
or slide A, of a well known construction, and such as I propose to use
for regulating the admission of air to furnaces-One end of the beam i,
is in connection with the wire or chain f, and the opposite end with the
damper or slide, which is supposed to be closed when the inaguets are
put in action-On the circuit being broken, the spring k, opens the same
by depressing the arm of the beam i, to which it is attached.
Fig 2 represents an end elevation, partly in section, and Fig. 3, a
front view of one of my regulating apparatus, as applied to the regu-
lating and maintaining of the temperature of the water or steam in
a steam boiler.
a,
is a bar or rod of lead or other suitable metal of any convenient
length, contained within an iron tube b, into the end piece c, of which
it is rivetted. The tube 6, is screwed into the iron plate d, and the
latter to the front plate . of the boiler, the end piece c, being sus-
tained from the side or end of the boiler in a corresponding position-
The rod a is therefore at liberty to expand in the direction of the arrow,
and in doing so,
the end e, comes in contact with the plate f, of ivory,
dovetailed into the lever g, of brass, which is held down by the spring 1,
the latter being in communication with one of the poles i, of the battery.
With the ivory plate k, which is fixed to the plate d, by the screws 1,7
and at a distance from it, which can be regulated by the thickness of
the blocks m, m, is connected the dial plate n, in communication with
the opposite pole by the wire o. The two poles remain isolated by means
of the plate k, until the rod a. by its expansion brings the lever 9, which
is hinged to the plate k, in contact with the set screw p, whereupon the
circuit is completed, and the electro-magnets are caused to act upon
the dampers or slides, until the normal temperature being again esta-
blished, the rod a. recedes, allowing the lever g. to be depressed, and to
break contact with the set screw p. The dial plate 2, is divided into
any requisite number of degrees, and the thread of the screw p, is so
proportioned, that when the hand g, is brought opposite to the number
indicating the degree of heat desired, the temperature will be main-
tained at that degree.
When the regulating apparatus is to be applied to steam boilers, I

page_text: prefer to make use of the well known thermo-electric battery, in conse-
quence of its cheapness and convenience. The thermo-electric battery
is placed within the brickwork of the boiler, so that one side of it comes
in contact with the heat of the furnace, and the opposite side with the
water contained in a small reservoir or cistern, which by circulation is
kept at a comparatively low temperature. The ashpit is completely
closed, the requisite supply of air arriving through flues in which
dampers with their magnets are placed, of a construction similar to that
described with reference to Fig. 1.-A dome fitted with a slide in con-
nection with a set of electro-magnets may also be placed on the top of
the chimney. From the battery the various wires are passed to the
apparatus, which is fixed in the front of the boiler, as well as to the
magnets, these wires being secured in convenient and safe positions.
When the apparatus is in action it will alternately open and close the
dampers &c. according to the temperature of the furnace and boiler
as already described.
Fig 4 represents a longitudinal view, and Fig: 5, a ground plan of
one of my regulating apparatus, as applied to the regulating and main-
taining the temperature of the wind in hot blast furnaces. a, is a plug
of clay, earthenware, or other substance of a similar nature, which is
inserted into a box or casing, through which the wind has to pass to the
furnace. Into one end of the plug a, the bar or rod b, is fixed, which
is in connection with the rod c, by means of the lever d, having its ful-
crum at, the rod c, passing through a hole in the plug a, large
enough to allow it to move freely. It is evident that by the expansion
of the rod b, in the direction of the arrow 6, as well as by its own ex-
pansion, the rod c, will be forced in the direction of the arrow c¹.―The
pole e of the battery is in connection with the rod 6, and the opposite
pole f, is in connection with the piece g, which is fixed into the plug a,
and so long as the rod c, and the set screw 7, do not meet, the circuit
is interrupted, and the magnets remain inactive-As soon, however,
as contact takes place between c, and h, the electro-magnets open
the dampers or valves, cold air is admitted, and thereby the normal
temperature re-established.
Fig 6 is an end view, and Fig. 7 a top view of an apparatus which

page_text: I propose to apply when a certain degree of temperature is to be main-
tained with the least possible variation. It is supposed to be connected
with a thermo-electric battery, which is not shewn in the Drawing.
The wires a, a¹, proceeding from the thermo-electric battery are in con-
nection with the coil of wire b, b, within which is placed on a spindle
an astatic needle c, c which is acted upon by a spiral spring d, and
which so long as the normal temperature is maintained, is pressed
against the plate c, made of ivory, and fixed to the segment f. As soon
however, as the heat with which one side of the thermo-electric battery
is in contact, increases (the battery supplying in this instance the place
of a thermometer) the needle c, c, will be deflected in the direction of
the arrow, until, on its reaching the pin 9, the circuit is completed ;
inasmuch as by means of the segment f, the needle c, c, will then be in
connection with the pole 7, as well as with the opposite pole i. The
electro-magnets will therefore be made to act upon the dampers &c.
in the manner already described. According to the temperature required
to be maintained the pin g, may be placed in any of the holes k, k, k;
in the segment f.
Fig. 8 is a front view, and Fig: 9, a side view of one of my regu-
lating apparatus, as applied to the regulating and maintaining the tem-
perature of the air in buildings, rooms &c. a is a plate of ivory upon
which a strip of lead, b. is screwed at one end, the opposite end being
inserted into a recess c. This strip of lead is somewhat reduced in
thickness at d, and at d¹, so that on expanding by the heat of the air
with which it is in contact being prevented from elongating in the
direction of c and d, it will bend at d, and d' and finally come in contact
with the set screw e, which passes through the dial plate f, and carries
the hand g.
The dial plate f is fixed to the plate a, by means of the
screws, and blocks ³, and h³; the strip of copper i, and block and
screw, uniting it with one of the poles 1, whilst through the screw e,
and strip b, it is in communication with the opposite pole m, whereby
the circuit is completed, and the dampers or valves for the admission
or exclusion of hot or cold air actuated in the manner already de-
scribed.
'The same effect might be produced by the application of two pieces

page_text: of metal of unequal expansion, soldered or otherwise joined together
and connected with one of the poles at one end; since according to
the temperature of the medium the strip would bend, and the circuit
would be completed, or broken, by the opposite end coming in contact
with the other pole or receding from it.
In cases where the apparatus described with reference to the fore-
going Figures are not conveniently applicable, I avail myself of the
ordinary mercury thermometer, either as shewn in Fig. 10, or as shewn
in Fig: 11. In Fig: 10 two isolated wires a, and b, are introduced
into the glass tube c¹-c, c, representing the column of mercury, upon
which is placed a cylinder d, of steel, in order to prevent its capillary
expression;-When by the expansion of the mercury, it rises in the
glass tube, it raises the cylinder d, and as soon as the heat has acquired
the degree to which the distance between the cylinder d, and the wires
a, and 6, has been regulated, they come in contact, thereby completing
the circuit, and causing the dampers or valves to act, as already
described.
In Fig. 11 the wire corresponding with one of the poles is welded
into the lower part of the bulb containing the mercury, instead of the
two wires being placed side by side.
An apparatus similar to that described with reference to Figs. 10
and 11 might be applied for the purpose of regulating the temperature
of water for baths. I call such apparatus "thermostator."
Fig. 12 represents one of my apparatus for regulating the hygro-
metric state of the air in rooms, buildings &c. It is constructed upon
the principle of Saussure's hair hygrometer. The hand a, is in connec-
tion with one of the poles, and the segment b, with the opposite pole-
The segment b, like that shewn in Fig. 7, is provided with any con-
venient number of holes c, c, &c., in any one of which a pin d may be
placed, according to the degree of moisture required to be maintained-
That degree being attained, the hand a will come in contact with the
pin d. and by completing the circuit, cause the dampers or slides to act,
and to admit either dry or moist air, as may be required, until the
normal state is re-established.-Other and less sensitive hygrometers
may be employed to effect the same purpose.

page_text: Fig: 13 represents an apparatus for regulating the strength of
spirituous liquors, or chemical mixtures. a, is an ordinary hydrometer
floating in the mixture whose strength is to be regulated and placed in
the centre of a ring of cork b, b, which also swims in the mixture.
Upon the cork ring b, b, are fixed two standards c, between which is a
cross piece d, with a loop in the middle of it, through which the stem a¹,
of the hydrometer passes, and by which the instrument is held in its
place. The standards c, are provided with flanches c¹ which support
the wires e, f, and 9, the latter being isolated, and held between the
pieces of ivory h, h, h. The continuations i. and . of the wire g, which
have a certain degree of elasticity, pass through the loop A, at the top
of the stem which latter is cemented to the stem a¹. of the hydrometer.
As soon as the mixture has acquired more than the desired degree of
strength, the hydrometer will sink and bring the spring & in contact
with the wire e, thereby completing the circuit, and causing the cock or
valve admitting the spirit, or the stronger ingredient, as the case may
be, to close If on the contrary the mixture has for the moment less
than the required degree of strength, the hydrometer will rise, and
bring the spring k in contact with the wire f, when the electro-mag-
nets will cause that valve or cock to be closed which admits the water
or weaker ingredient-Or, the operation of opening and closing the valves
may be reversed. It is evident that so long as the mixture maintains
the required degree of strength, the springs i, and k, will not touch
either of the wires e. and f, and therefore both the spirit and water will
continue to flow in simultaneously,
It is scarcely necessary to observe that the various apparatus which
I have shewn and described are supposed to be placed in casings or
boxes so as to protect them from injury.
The electro current has been used in combination with thermometers
for the purpose of indicating the degree of heat of the water in steam
boilers, and the temperature of the air in rooms or buildings, by causing
an alarum to sound. I do not claim the combination of the electric
current with a thermometer, for the purpose of indicating the tempera-
ture, nor the peculiar construction of the electro-magnets, dampers, or
apparatus shewn and described. But what I claim is :

page_text: Firstly. The regulating and maintaining the temperature of water, air,
or other fluids, by effecting the opening and closing of dampers, slides,
valves, cocks, &c. by means of the electric current.
Secondly The indicating and regulating the degree of strength of
spirituous liquors or chemical mixtures by means of the hydrometer
in combination with the electric current.
Thirdly. The indicating and regulating and maintaining the hygro-
metric state of the air in buildings, rooms &c. by means of the hygro-
ineter in combination with the electric current.
In witness whereof I the said Henry Kraut have hereunto set
my hand and seal this Twenty-fourth day of April in the
year of our Lord One thousand eight hundred and fifty-four.
HENRY KRAUT (L.S.)