IMPROVEMENTS IN REGULATING THE WORKING OF VACUUM PANG ADDIIDED 434 SUGAD ROLLING VD TAT ADDIDATUS TITED BEAD DADES OF WHICH INVENTION ARE ALSO APPLICABLE IN FRACTIONAL DISTILLATION.”
Year: 1881

page_text: LETTERS PATENT to Alexander Watt, of Liverpool, in the County of Lancaster,
Fellow of the Institute of Chemistry and Fellow of the Chemical Society, for
an Invention of "IMPROVEMENTS IN REGULATING THE WORKING OF VACUUM
PANG ADDIIDED 434 SUGAD ROLLING VD TAT
ADDIDATUS TITED BEAD
DADES
OF WHICH INVENTION ARE ALSO APPLICABLE IN FRACTIONAL DISTILLATION.”
PROVISIONAL SPECIFICATION left by the said Alexander Watt at the
Office of the Commissioners of Patents on the 14th May 1881.
ALEXANDER WATT, of Liverpool, in the County of Lancaster, Fellow of the
Institute of Chemistry and Fellow of the Chemical Society. "IMPROVEMENTS IN
REGULATING THE WORKING OF VACUUM PANS APPLICABLE FOR SUGAR BOILING,
AND IN APPARATUS THEREFOR, PARTS OF WHICH INVENTION ARE ALSO APPLICABLE
IN FRACTIONAL DISTILLATION.”
The object of this Invention is generally to accomplish by mechanical means
what has hitherto been attained only by constant and careful watching and
regulating by a skilled sugar boiler, and to obtain a more uniform grain of
sugar.
In the boiling of sugar liquors "to grain" in a vacuum pan, it is as is well
known important that the sugar boiler should be careful to admit fresh liquor into
the pan only at the exact moment when the liquor in the pan has attained the
necessary concentration, and also in sufficient quantity to produce the particular
character of crystallization desired. If the consistency of the boiling liquor in the
pan be too great before admitting fresh liquor, a great precipitation of fine crystals
takes place (technically known as "false grain"). It is to avoid this formation of
"false grain" and thereby increase the value of the sugar obtained that this my
Invention is partly designed.
In this Invention advantage is taken of the fact that under a constant pressure
(constant vacuum) the boiling point of the sugar liquor (in common with other
solutions) rises with the degree of concentration.

page_text: In order to utilize this fact a sensitive electric thermometer with contacts capable
of being adjusted to any desired temperature is placed in the vacuum pan, and the
vacuum gauges have adjustable electric contacts which may be adjusted either to
make contact at a maximum or a minimum pressure, or at both. Wires are led
from the electric thermometer and the electric vacuum gauges to electro-magnetic
valves actuated by a current of electricity derived from a dynamo electric machine
or other convenient source. The contacts are so arranged that the electricity acts
on the respective valves, instantly opening or closing them, as the temperature or
pressure, or both, reach the maximum or minimum limits to which the contacts are
adjusted.
The contacts of one of the electric vacuum gauges are so connected with the
electro-magnetic valve, which admits air into the pan (by two pipes, one opening
under the liquor and the other furnished with a stopcock above the level of the
liquor), and with the electrical arrangements of the valve which admits liquor,
that when the vacuum rises above the maximum or falls below the minimum
point the valve is opened or closed, and so maintains a constant vacuum.
The contacts and wires of the electric thermometer are so connected with another
electric vacuum gauge that the current of electricity must pass through both on its
way to the electro-magnetic valve which admits the liquor to the pan, and that on
the desired temperature and pressure (e.g., concentration) being reached the
electrical circuit of the liquor valve is completed, and at the same time the circuit
of the first mentioned electric vacuum gauge is broken, thereby opening the liquor
valve and closing the air valve. Liquor is thus admitted into the pan (until the
temperature falls sufficiently to break the circuit) and the vacuum is increased and
so hastens the fall of the temperature of the pan.
The air valve for regulating the vacuum in the pan can be supplemented or
replaced when necessary by an electro-magnetic valve attached to the pipe which
supplies water to the condenser. This valve may either be connected with an
electric thermometer placed in the condenser or with the minimum contact of one
of the electric vacuum gauges, or with both. If the temperature of the condenser
rises above the maximum point, or the vacuum falls below the minimum point,
this valve is opened and admits water to the condenser, and so regulates the
vacuum.
The steam valves of the pan may be placed in electrical connection with a
pressure gauge or float for showing the depth of liquor in the supply tank. As the
depth of liquor diminishes therein, one after another of the steam coils will thus be
opened by electrical adjustments similar to those above described. The pressure of
the steam may also be regulated by similar valves and pressure gauges. These
electro-magnetically regulated or actuated valves admit liquor to regulate the
consistency, air to equalize the pressure and regulate the pressure of the steam and
its admission to the various coils respectively, and are actuated by the current
regulated by contacts on the vacuum gauges or thermometer, or both.
If desired, the electric thermometers, vacuum and pressure gauges, may be caused
to actuate electric bells, whistles, or indicators, when the respective valves may be
opened by hand and closed again when the bell, whistle, or indicator ceases to
indicate.
By the combination of these valves I so control the supply of liquor to the
vacuuin pan that it shall only be admitted at the precise moment required, and
only in the requisite quantity, thereby enabling the boiling to proceed with great
regularity.
This Invention is applicable to fractional distillation as far as relates to
continuous feeding so as to maintain the contents of the still at such a composition
as to cause the distillate to be a uniform product for longer periods than possible
under the old process, or changing the receivers at the right moment by means of
electric contact taking place when the boiling point reaches a given temperature.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Watt in the Great Seal Patent Office on the
14th November 1881.
ALEXANDER WATT, of Liverpool, in the County of Lancaster, Fellow of the
Institute of Chemistry and Fellow of the Chemical Society.
博客 * IMPROVEMENTS IN
REGULATING THE WORKING OF VACUUM PANS APPLICABLE FOR SUGAR BOILING,
AND IN APPARATUS THEREFOR, PARTS OF WHICH INVENTION ARE ALSO APPLICABLE
IN FRACTIONAL DISTILLATION."
The object of this Invention is generally to accomplish by mechanical means
what has hitherto been attained only by constant and careful watching and
regulating by a skilled sugar-boiler, and to obtain a more uniform grain of sugar.
In the boiling of sugar liquors "to grain" in a vacuum pan, it is as is well
known important that the sugar-boiler should be careful to admit fresh liquor into
the pan only at the exact moment when the liquor in the pan has attained the
necessary concentration, and also in sufficient quantity to produce the particular
character of crystallization desired.
If the consistency of the boiling liquor in the pan be too great before admitting
fresh liquor, a great precipitation of fine crystals takes place, technically known as
"false grain."
It is to avoid this formation of "false grain," and thereby increase
the value of the sugar obtained, that this my Invention is partly designed.
In carrying out my Invention I use what I will term electro magnetic valves
for admitting the various fluids into the vacuum pans and condensers, these being
all of a similar type, but each controlled partially according to its position or use
by electrical thermometers or vacuum gauges, or both, as the case will admit of or
be found most expedient. The connection between these valves and the thermo-
meters or gauges being so arranged that the alteration of the position of the
mercury will either cause to flow or stop the flow of a current of electricity
through the electro magnet controlling the valve, and so cause the valve to open
or shut as required, this current of electricity proceeding from a dynamo electric
machine or other sufficiently powerful generator of electricity. Referring to the
Drawings, on-
Sheet I. is represented the design of electro magnetic valve I prefer; on
Sheet II. details of electrical apparatus for controlling the working of the electro
magnetic valve; on
Sheet III., designs of thermometers and vacuum gauges with their connections; on
Shect IV., a diagram shewing the general arrangement of the connections of the
wires carrying the electricity from the generating machine to the electro-magnetic
valves and to the controlling mechanism; on
Sheet V., diagram, shewing the connectious of wires for the part of the Invention
which is adapted to fractional distillation; on
Sheet VI, electrical hydrometer and arrangements for intermittently and
permanently breaking electric circuits.
Fig. 1 is an elevation partly in section of the electro magnetic valve.
Fig. 2, plan view of Fig. 1.
Fig. 3, elevation (on larger scale) of small magnet shown off at (C) Fig. 1.
Fig. 4, plan view of Fig. 3.
Fig. 5, sectional plan of Fig.
Fig. 3 is seen at C in Fig. 1.
on line x, x, (an end elevation of apparatus in
Fig. 6, air thermometer for vacuum pan.
Fig. 7, vacuum gauges.
Fig. 8, mercurial thermometer for condenser pipe.

page_text: the condenser.
Fig. 10, diagram shewing electrical connections of the valve for admitting air
to regulate the vacuum.
Fig. 11, diagram shewing electrical connections to the valve for admitting
saccharine liquor into the vacuum pan.
Fig. 12, diagram shewing arrangement of wires for apparatus for changing
receivers in fractional distillation.
Fig. 13, diagram shewing electrical connections for automatic feeding in fractional
distillation.
Fig. 14, pressure gauge used in connection with liquor supply tank.
Fig. 15, enlarged detail of automatic device for breaking electrical contacts.
Fig. 16 electrical hydrometer.
The electro magnetic valve I prefer to use, see Figs. 1 and 2, consists of an
ordinary Cornish valve A loaded by a weight a to keep it shut, and two electro
magnets, a large magnet B, and a small one C, the large magnet oparating the
valve and the small one controlling or regulating the current of electricity to the
large one. The armature D of the magnet B is so fixed on the lever E that its
movement is multiplied about six times, so that the valve rod F has a stroke of
about three quarters of an inch. The small magnet C is placed in direct electrical
connection with the thermometers or vacuum gauges, and when actuated by
comparitively weak current of electricity from a primary battery, or a shunt
circuit from the dynamo machine, or from a secondary battery charged by the
dynamo machine, shewn in the diagram Sheet 4, it moves its armature G and
makes contact at H, thereby sending a strong current of electricity from the
dynamo machine to the magnet B, which attracts its armature D and opens the
valve A. At the same time another contact at I, see Fig. 5 (which in its normal
position brings a secondary battery and a suitable resistance coil into the current
of the dynamo machine) is broken.
On the circuit of the small magnet being broken its armature springs back, and
by the same movement a bent piece of asbestos, card board, mica, or other non
combustible non conducting material. .K, Figure 3, Sheet 2, is thrown in between
the platinum contacts H, thereby preventing any inconvenience that might arise
from the sparks which occurs on breaking contact. This cardboard is of course
withdrawn when contact is made. On Sheet II. this arrangement is shewn in
detail on an enlarged scale. Care a pair of electro magnets connected through
binding screw (19) with the gauge or thermometer through which it is sought
to control the valve A, and through binding screw (20) with a primary or
secondary battery or other generator of a weak current of electricity. G is the
armature of the magnets C carrying an arm g, which when the armature is
attracted to the magnet is brought against a contact maker H, completing the
circuit from the dynamo machine to the electro magnet B, the wires being attached
to the binding screws (22) and (23). K is a small sheet of asbestos, cardboard,
mica, or other non-combustible or non conducting material, pivoted on two
brackets at k, and hinged or connected to the arm by a link h, so that when the
armature G and arm g return to their normal position and contact is broken, it is
thrown between H and g, and cuts off any sparks that would naturally arise.
J is a small coiled spring which keeps the arm g when the armature G is not
attracted by the magnet in a fixed position and in contact at I.
In order to take advantage of the fact that under a constant pressure (constant
vacuum) the boiling point of the sugar liquor (in common with other solutions)
rises with the degree of concentration, a sensitive electric thermometer, with contact
capable of being adjusted to any desired temperature, is placed in the vacuum pan,
and the vacuum gauges have adjustable electric contacts which may be adjusted
either to make contact at a maximum or minimum pressure, or at both.
The thermometer I prefer to employ is an air thermometer constructed as shewn

page_text: in Fig. 6, Sheet 3. The bulb A is a ring of copper pipe, about one and a half
inches in internal diameter, and about five feet in circumference.
One end of the pipe A is closed, and into the other end of it a strong copper
pipe B is screwed and soldered or otherwise attached, so as to be airtight; the
pipe B has an external diameter of about half an inch, and a bore of one eighth of
an inch in diameter. The other end of the pipe B is connected, as shewn in Fig. 6,
to a U shaped barometer tube C, open at both ends, about three feet long and one
eighth inch bore containing mercury; a platinum wire is sealed into the tube
at a and connected by a wire to the binding screw 1. Into the open limb of the
tube a long platinum wire b is placed, and is connected to the long screw c, which
can be adjusted to any position in the tube by means of the fixed nut d, which is
in electrical connection with the binding screw 2.
The vacuum gauges are shown in Fig. 7, and are placed for convenience in the
same wooden case as the indicating part of the air thermometer.
The gauge A is a U barometer tube (similar to that used for the air
thermometer).
The gauge B is an open barometer tube, with cup about three inches long and
one and a quarter inch diameter.
One end of each of the tubes A and B is cemented into the brass tubes (h) and
(m) respectively. These brass tubes are connected together, as shewn in the Fig. 7,
by the tube C, D, which leads to the vacuum pan, and are each furnished with a
stuffing box, through which passes the platinum wires g and l, enclosed to within
half an inch of their point in the insulating glass tubes i and k. The platinum
wires are connected electrically and the glass tubes mechanically with the moveable
screws n and o respectively, which are in electrical connection with the binding
screws 5 and 6.
Into the open limb of the tube A a moveable platinum wire is placed connected
electrically with the binding screw 4.
A platinum wire is sealed into the gauge A at the bend and is connected
electrically to the binding screw 3, and a platinum wire connected electrically to
the binding 7 is placed in the cup of the gauge B.
The gauge A is filled to half its length with mercury, and the cup of the gauge B
is filled about three quarters full of mercury.
Wires are led from the electric thermometer and the electric vacuum gauges to
the electro-magnetic valves. The contacts are so arranged that the electricity acts
on the respective valves, instantly opening or closing them as the temperature or
pressure, or both, reach the maximum or minimum limits to which the contacts are
adjusted.
The contacts of the electric vacuum gauge A, Fig. 9, are so connected with the
electro magnetic valve V2, Fig. 10, which admits air into the pan by two pipes (one
opening under the liquor and the other furnished with a stop cock above the level
of the liquor), that when the vacuum rises above the maximum or falls below the
minimum point, the valve V' is opened or closed, and so maintains a constant
vacuum.
The contacts and wires of the air thermometer, see Fig. 11, are so connected with
another electric vacuum gauge B, Fig. 11, that the current of electricity must pass
through both on its way to the electro magnetic valve V³, Fig. 11, which admits
the liquor to the pan, and that on the desired temperature and pressure
(e.g., concentration) being reached the electrical circuit of the liquor valve Vs is
completed, and at the same time the contact N of the first mentioned electric vacuum
gauge A, Fig. 9, is broken. The liquor valve is thus opened and the air valve is
kept shut, increasing the vacuum and so shortening the duration of the feed through
the liquor valve. This causes the feeding to be almost continuous. If it be desired
that the feeding should continue for a longer period, the switch T is moved to the
point t, thereby preventing the circuit of the air valve being broken.
The air valve V2 for regulating the vacuum in the pan can be supplemented or

page_text: T
eplaced when necessary by the electro magnetic valve V₁ attached to the pipe
which supplies water to the condenser.
"
This valve may be connected with an electric thermometer, in which case I
prefer a mercurial one, which is most advantageously placed in the "tail pipe
(waste pipe) from the condenser. It is shewn in Fig. 8. It is open at the top, and
has a platinum wire (a) fused into the bulb A and connected to the binding screw 9;
a moveable platinum wire b is connected to the binding screw 8, and is adjusted by
means of the nut d in the same manner as that described for the air thermometer.
Or it may be connected with minimum contact of one of the electric vacuum gauges,
or with both. If the temperature of the condenser rises above the maximum point
or the vacuum falls below the minimum point, the valve is opened and admits
water to the condenser and so regulates the vacuum.
The steam valve of the plan may be placed in electrical connection with a
pressure gauge or float for shewing the depth of liquor in the supply tank.
The pressure gauge I employ for regulating the admission of steam to the coils
of the vacuum pan, as the depth of liquor in the supply tank diminishes, is shewn
in Fig. 14, Sheet 6. It consists of a metal tube a little longer than the depth of the
tank for which it is required, open at the bottom and having at its upper end a
glass tube cemented into it, bent as shown at B, Fig. 14, at a suitable point on the
limb a (dependent on the depth of the tank and the density of the liquor), a
platinum wire is sealed into the tube and connected to the binding screw 10.
Into the open limb b of the tube a piece of small bore barometer tubing is inserted
capable of being moved freely up and down, and in the bore of this tube a moveable
platinum wire is placed and connected to the binding screw 11.
Another platinum wire connected to the binding screw 12 is sealed into the
bend B of glass tube. The bend of this gauge is filled with mercury, and the piece
of moveable tubing inserted in the open limb is used for adjusting the position of
the mercury in relation to the platinum wire at the point a, and is kept in position
by means of a piece of india rubber tubing, a cork, or other suitable manner.
The platinum wire is adjusted by means of a regulating screw similar to those
described for the thermometers and gauge shewn on Sheet 3.
When the long tube is placed in the tank full of liquor, the mercury will rise in
the open limb, and by above mentioned means the wires may be adjusted so as to
make contact either at a rise or fall in the depth of the liquor, and so ring an
alarum bell, or open or shut the electro magnetic valve.
As the depth of liquor diminishes in the tank, one after another of the steam
coils will then be opened by a series of electrical adjustments similar to those above
described.
It is advantageous to employ pressure gauges similar to the above for breaking
the circuits of the liquor and water valves, and at the same time ringing alarum s
bells on the liquor tank or water tank becoming empty. For this purpose the
current of electricity is made to pass through this gauge on its way to the valves,
the arrangement of wires being shewn in the diagram, Fig. 13, Sheet 5, relating to
fractional distillation.
The action of the apparatus is as follows:-
The sugar boiler charges the vacuum pan with "liquor" in the usual way, and
by means of the ordinary stop cocks, but in the making of the "grain," instead of
regulating the temperature and vacuum of the pan by means of the ordinary valve
which admits water to the condenser, the moveable contact of the electric ther-
mometer in the "tail" or waste pipe of the condenser should be varied until the
desired temperature and vacuum are obtained. Or the same result can be obtained
by adjusting the ordinary water valve of the condenser so as to give a supply of
water a little under what is required to maintain the vacuum wanted, and then
lowering the contacts of the vacuum gauge A, Fig. 9, Sheet 4, the maximum
contact so as just to touch the mercury, and the minimum conduct so as almost to
touch the mercury.

page_text: The former plan may be used when it is desired to boil at a low temperature,
and the latter when a high temperature is required. When "grain" has been
obtained and it is desired to maintain the contents of the pan at the same degree
of concentration, the contacts of the vacuum gauge A and the mercurial thermo-
meter E, Fig. 9, are readjusted to the vacuum which it desired to boil at. When
this vacuum is attained the contact O of the vacuum gauge B, Fig. 11, is lowered
until it dips into the mercury to a depth proportionate to the range of vacuum
it is desired, and the contact of the air thermometer C, Fig. 11 is made to touch
the mercury just at the moment when it is desired to let liquor into the pan.
The liquor valve V³ will then be opened and will remain open until the liquor in
the pan has been thinned sufficiently to lower the boiling point and so break the
circuit, provided the contact O of the vacuum gauge B has not been broken, as it
is only when the temperature and pressure coincide and reach the previously fixed
limits that liquor can be admitted. When the liquor valve V³ is open the circuit
of the air valve V2 is broken, as shown in the diagrain, Sheet 4, and so increase the
vacuum and shortens the duration of the feeding. If necessary the water valve V₁
may be opened simultaneously with the liquor valve V³, thereby effecting the
same purpose.
The liquor valve V³ being closed, the air valve V2 is again put into action and
reduces the vacuum to its normal state, the boiling point rises, and when it has
returned to the point at which the air thermometer C, Fig. 11, contact P, was
originally fixed, the liquor valve Vs is again opened as before, the cycle of operations
being repeated and continued until the contacts of the various gauges are altered.
The pan will thus continue to feed itself regularly for as long a period as may be
desired. When the supply tank containing the liquor is nearly empty, an alarm
bell warns an attendant who now conducts the boiling of the final stage in the
usual manner.
Instead of opening valves which admit steam to the coils of vacuum pan
automatically, it is more convenient to use the pressure guage, Fig. 14, placed in
the supply tank in connection with an electric bell, and to open the steain valves
by hand.
DESCRIPTION OF THE ELECTRICAL CONNECTION SHOWN IN THE DIAGRAM,
SHEET 4.
D is a dynamo-electric machine which may be driven by the engine which works
the vacuum pumps; a and b are the two main wires from the dynamo machine.
Three similar branch wires are led from the main wire a through the levers of the
small magnets m³, m³, and m³, making contact in the normal position of the levers
at c, d, and e with one pole of its secondary battery of Planté and Faure cells, S¹, S³,
and S3, and suitable resistance coils R1, R2, and R³, the other pole of the battery
being connected to the main wire b. In this position of the levers the current
from the machine is passing through the batteries and keeping them charged; A is
the vacuum gauge used in connection with the magnet M¹ of the water valve V¹,
and the magnet M³ of the air valve V2; E is the mercurial thermometer used in
connection with the magnet M' of the water valve V₁; B is the vacuum gauge,
and C is the air thermometer used in connection with the magnet M³ of the liquor
valve V³ Q is a switch by which the circuit of the air valve V2 may be
permanently broken by hand, or intermittently broken by the action of the lever
of liquor valve Vs.
The switch H when in contact at I connects the water valve with the mercurial
thermometer, and when in contact at K with the minimum contact of the vacuum
gauge A.
Fand G are resistance coils, each equal to the resistance of the large magnets M'
and M³, which are equal to each other; p' and p² are plugs which, in the position
shewn in the diagram, send the current through the magnets M¹ and M separately,
and when they are both removed from their holes and one of them inserted in the

page_text: hole O³, the water valve is opened simultaneously with the liquor valve by the
combined action of the air thermometer C and the vacuum gauge B. The currents
for actuating the small magnets m³, m², and m³, as will be readily seen from the
diagram, are obtained from the secondary batteries, and the currents for the large
magnets direct from the dynamo machine. It will also be seen that at the
moment the current passes through the small magnets, the current from the machine
is diverted from the charging of the batteries, and is sent through the large
magnets, leaving the small magnets to be actuated by the secondary batteries
only.
The application of this Invention to automatic feeding in fractional distillation,
so as to maintain the contents of the still at such a composition as to cause the
distillate to be a uniform product for longer periods than possible under the present
process, is accomplished by means of an electric thermometer A, Fig. 13, placed in
the still S, and an electro magnetic valve V similar to that herein before described.
The arrangement of the wires is shewn in the diagram, Fig. 13, Sheet 5.
In order to prevent the still being filled too full, a pressure gauge B, similar to
that above described and shown in Fig. 14, is fixed to the still, as shewn at bin
the diagram, Fig. 13. When the switch D is in contact with f, the contacts are so
arranged that on the liquid in the still reaching a certain height, the electric
connection at c to feeding valve V is broken, and contact made at d, and an
electric bell rings. On the contents of the still falling again below this maximum
level the feeding arrangement will again be put into action. If this is not desired,
then by connecting the switch D to the point e, the current of electricity is made
to pass by the binding screws 15 and 16 through the apparatus shewn in detail in
Fig. 15, which consists of a glass tube G with mercury placed inside, into which
the wires are sealed, as shewn. When the electric bell rings the rod g attached to
the hammer of the bell strikes against the point h attached to the glass tube G,
causing it to fall over, and the mercury, which in its normal position remains in
the limb of G, into which the ends of the wires project, fulls over into the other
end, thus breaking contact until the apparatus is reset by an attendant; H is a
spring on which the end K of the glass tube rests and holds it balanced, so that
the mercury flows out on the least alteration of position in an upward direction.
In this arrangement, when the maximum height is reached, an alarm bell is
rung, and the valve circuit is permanently broken.
The arrangement of the apparatus for changing receivers in fractional distillation
is shewn in Fig. 12, Sheet 5; O is the dynamo machine, with the main wires M
and N; V, V, V, and V are simple electro magnetic plug valves, as shewn in the
diagram, the electrical parts of which are exactly similar to those previously
described and shewn on Sheets 1 and 2; M', m', 'M², m², M³, m³, M, m, are the
large and small magnets of the valves respectively.
The valves are arranged to close the branch pipes p', p³, p³, p*, leading from the
main pipe P to the receivers.
A is an air thermometer similar to the one previously described, with this
difference, that instead of having one moveable wire, it has one for each temperature
at which it is desired to change the receiver. These platinum wires may be sealed
into the glass at the required intervals, or more conveniently, as shown in the
diagram, a number of insulated wires may be inserted into the tube (which must of
course have the requisite width), and their positions in the tube may be adjusted
by means already described.
Instead of a secondary battery, in this case I prefer to use a shunted current
through the large resistance R2 from the dynamo machine D for actuating the small
magnets. R' is a resistance coil, through which the current from the dynamo
machine D passes when all the valves are out of action, so as to magnetize the field
magnets of the machine.
The wires are so arranged that at whatever temperature is reached only one
valve shall be open at a time, and that the valve that is open shall remain so until

page_text: the next temperature is reached, when the valve next in order is opened, the
operation breaking the circuit of all the preceeding valves.
On the levers 22, 23, and 2 of the small magnets m², m³, and m³, insulated contacts
02, 0, and o are placed, through which the circuit of the small magnet m¹ is
carried. The circuit of m² is in like manner carried through the contacts o³ and o*,
and the circuit of m³ is carried through o*, the circuit of m going directly back to
the machine through the resistance R. It will thus be seen that when the mercury
in the thermometer reaches wire a the magnet m¹ is only affected; when the
mercury reaches wire b the current acts on m³, and at the instant that the armature
of m² is attracted the circuit of the magnet m¹ is broken, thereby closing the
valve V at the same time that V2 is opened; on the mercury reaching wire c the
circuit of m³ is broken, valve V2 shut, and V3 opened, and so on for any number of
valves.
Instead of using an electric thermometer for regulating the changing of the
receivers, a series of elastic hydrometers may be used with the same system of
valves. The electric hydrometer (although not claimed as part of my Invention)
is shewn in Fig. 16.
A is a glass hydrometer open at the top containing mercury in the bulb.
B is a glass tube containing two insulated wires which are uncovered at the points.
This tube contains the scale of the instrument, and may be adjusted so that the two
wires will touch the mercury in the bulb at any required density. The cylinder C
containing the hydrometer is arranged so that the liquid enters in a gentle stream
at the bottom of the vessel at D, and overflows in it the larger vessel E, and escapes
by the pipe F so as to maintain a constant level.
These electro magnetically regulated or actuated valves admit liquor to regulate
the consistency, air to equalize the pressure, water to the condenser, and steam to
the various coils respectively, and are actuated by the current regulated by contacts
on the vacuum gauges or thermometer, or both.
If desired the electric thermometer vacuum and pressure gauges may be caused
to actuate electric bells, whistles, or indicators, when the respective valves may be
opened by hand, and closed again when the bell, whistle, or indicator ceases to
indicate.
By the combination of these valves I so control the supply of liquor to the
vacuum pan that it shall only be admitted at the precise moment required, and
only in the requisite quantity, thereby enabling the boiling to proceed with great
regularity.
Having now described my Invention, and the best modes known to me of
carrying it into effect, I wish it to be understood that I do not claim the regulating
of heat generally by means of a thermometer with electric contacts, nor by means
of a pressure or vacuum gauge taken separately, but that what I believe to be new
and desire to protect under the hereinbefore in part recited Letters Patent is,-
1st. The various forms and combinations of electrical apparatus, substantially as
herein set forth, as described, for regulating sugar boiling, fractional distillation, or
other industrial operations in which evaporation under uniform conditions of
temperature and pressure is required, no claim being made for any one part takeu
separately or when used for a different purpose, but only when combined with other
parts, substantially as herein set forth to form apparatus for the purpose described.
2nd. The mode of maintaining a uniform degree of concentration in a vacuum
pan for sugar boiling, consisting in regulating the admission of liquor by the combined
use of an electric thermometer and a vacuum gauge, together with a means for
regulating the pressure.
3rd. The application of a thermometer with electrical contacts, and means for
practically maintaining uniformity of pressure, with or without a vacuum of
pressure gauge, for the purpose of regulating the admission to a still of crude liquid
from which it is desired to separate such of its constituents as boil at a given
temperature and pressure, so as to maintain the contents of the still in such condition

page_text: as to cause the distillate to be a uniform product for longer periods than is
practicable by processes hitherto in use, substantially as described in the case of
sugar boiling.
4th. The method in fractional distallation of changing receivers by the aid of
electricity, substantially as set forth.
In witness whereof, I, the said Alexander Watt, have hereunto set my hand
and seal, this Eleventh day of November, in the year of our Lord One
thousand eight hundred and eighty one.
ALEXANDER WATI. (L.S.)