IMPROVEMENTS IN ELECTRO-MAGNETIC GOVERNORS FOR STEAM HEATING AND DRYING "Apparatus
Year: 1874

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN ELECTRO-MAGNETIC GOVERNORS FOR STEAM HEATING AND
DRYING "Apparatus.”—A communication from abroad by Julien May
Bradford, of Portland, in the County of Cumberland, and State of
Sealed the 25th September 1874, and dated the 29th July 1874.
PROVISIONAL SPECIFICATION left by the said Alexander Melvillé
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 29th July 1874.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in tho
5 County of Middlesex, Patent Agent, do hereby declaro the nature of
the said Invention for "IMPROVEMENTS IN ELECTRO-MAGNETIC GOVERNORS FOR
Steam Heating and Drying Appanafus,” to be as follows :—
This Invention comprises an engine for working a cut-off valve and
a throttle valve of steam heating apparatus with automatic apparatus

page_text: for opening and closing the valves; also for reversing and stopping and
starting the engine, the apparatus being controlled by electric currents
closed and broken by the variations of the heat through the medium of
thermomoters in the heated room. The arrangement is adapted to
ensure a uniform temperature of any required degree.
The machine is designed for use in connection with drying and
heating rooms of all kinds and purposes; the motive power is in this
case obtained by means of a steam engine or engines, but when
connection with machinery is available the special motor may be
dispensed with. '
1
The steam for the dry house is conducted by a pipe from the boiler
through a cut-off valve chest and regulating valve chest. Steam is also
taken to the engines for working said valves by another pipe which
is connected with the boiler below a partition therein, which in practico
will be provided with a valve in low-pressure apparatus to shut off the 1
steam temporarily from the dry house in case it may be necessary to
raise the pressure at any time it may fall so low as not to be capable of
running the engine.
:
•
The cut-off valve may be of the ordinary slide valve pattern, or any
other approved form, but it will probably be best to have the regulating
valve control a number of different passages to different coils of small
pipe rather than one coil of large pipe, because one large coil will not
cool so quickly when heated as several smaller ones of the same capacity
in the aggregate, so that by the use of the small coils with a valve so
arranged as to shut off some of them entirely while others are left
open something will be gained by the quicker action, and moreover
the different coils may be used for heating different rooms, all being
controlled by one regulator.
The cut-off valve is connected to a rod which extends into the valve
chest of the steam engine, and is also connected to a reversing valve, 3
so that whenever the cut-off valve is either open or closed the engines
can be reversed to shift the regulating valve accordingly.
The steam enters the valve chest of the steam engines through the
stopping and starting valve (which in practice will probably be a
balanced valve) whence it passes into the chamber of the reversing valve, å
and when the cut-off valve is opened and the reversing valve shifted

page_text: to the corresponding position the steam will enter the cylinder through
certain passages and valves and exhaust through other passages, but
when the cut-off valve is closed and the reversing valve shifted
accordingly the course of the steam will be reversed. These engines
turn a crank shaft which by means of pinions operate a large wheel
from which motion is obtained to work by means of a worm a
segmental wheel which is thus turned very slowly for the purpose
of working the regulating valvo with which it gears by a pinion and
rack as slow as may be needed to correspond with the changes of
temperature in the dry house.
An eccentric on the crank shaft works by a rock shaft and suitable
arms and rods a reciprocating sleeve on the rod which connects the
cut-off and the reversing valves. This sleeve slides freely on the rod,
and it carries a pawl pivoted at its centre, and provided with an
armature near the end next to the cut-off valve to be pulled down
by an electro-magnet, so as to catch a collar on the valve rod when
the valve is to be closed; it also has a spring for pulling the other
end down to catch another collar when the cut-off is to be opened.
A spring will be arranged under the segmental wheel to cause it to
engage with the worm for the reverse motion after having been turned
to the extreme of its downward movement; its gravity will cause it
to engage at the other extreme. Above the pawl is a small bar
insulated from the pawl box on which it rests by a piece of vulcanized
rubber. It carries a screw with a platinum point which touches a
platinum disc when the pawl is free from the magnet, a binding screw
connecting with said disc. This bar also carries another binding screw
which with the screw before mentioned includes the pawl in the
electrical circuit for controlling the stopping and starting valve, which
is connected with a rock shaft on which is a frame of soft iron carrying
a magnet. Directly over this magnet is an armature on a lever of
another rock shaft in the axis of the shaft which carries the magnet,
and connected with a wrist pin on a pinion by which it obtains its
motion from the crank shaft. The magnetic frame is separated so as to
cause the armature to make the connection between the two poles by
which its lifting power is increased.
Two thermometers are placed in the room to be heated; the one
thermometer has a steel rod and is included in the circuit of the
battery, the pawl, and magnet first described, whilst the other thermo-

page_text: meter which also has a steel rod is included in the circuit of the battery
and the magnet last described. The steel wire of the first thermometer
stands a little lower than the other to indicato by its lower.end the
degree of heat required.
When steam is let on by opening the cut-off valve, the regulating
valvo being partly open and the engine in motion, the regulating
valve will gradually open till the heat rises to the required point,
when it should be open just enough to allow enough steam to pass
to maintain the heat thercat and then stop. The engine will then
be stopped to allow said valve to remain at rest by the closing of
the circuit through the magnet last described by the mercury touching
the steel rod which will cause the frame carrying the said magnet
to be attracted by the armature, and held so that when its lever is
forced up the frame will be drawn up with it, and will close the
stopping and starting valve which is connected to its rock shaft...
Should the heat. then fall the circuit will be broken by the mercury
falling away from the steel rod, when the said frame will fall away
from the lever and set the engine in motion to open the regulating
valve still more. On the other hand, should the heat continue to
rise after the stopping of the regulating valve, the mercury in the
other thermometer will, by touching the steel wire, open the circuit
through the magnet first described, which will pull down the pawl
and also break the circuit through the other magnet, so that it will
fall and set the engine in motion, and the pawl will close the cut-off
valve and reverse the engine, which will close the regulating valve
also, and ensure the falling of the heat directly. As soon however
as it falls so that the circuit through the magnet first described is
broken, the pawl will be released and pulled down by its spring, so that
it will open the cut-off valve and again reverse the engine for again
opening the regulator, and so on.
The regulating valve may be operated by the engine, or any other
driving gear, and reversed without reversing the engine or other driving
gear by the following method:-A third magnet and a latch may be
fixed on an eccentric rod to connect or disconnect with an arm,
according to whether the electric current or the spring control the a
latch to work said arm or not. The arm is pivoted on the axis of
a wheel, and carries a double pawl to turn the said wheel which
works a pinion right or left, according to which, end of the pawl

page_text: engages with the wheel, and this will be determined by the position
of the rod of the cut-off valve by a little slotted piece on said rod
into which a pin on the pawl projects, so that when the said valvo
is open and its rod shifted the one way the lower end of the pawl
will engage the wheel, and when shifted the other way the upper
end will engage the wheel. In this case the mechanisn for working
the rod of the cut-off valve will be the same in all respects as in
the other, except that the rod connected to the sleeve will be worked
by a rock shaft operated by an eccentric on a shaft which is turned
by the crank shaft. When the current passes through the last-mentionc:l
magnet the latch will be pulled back and it will pass the lever without
effect.
To allow the rack of the regulating valve to be disengaged when
moved to the end of its range, while the pinion operating it continues
to move and to be engaged again when the motion of the pinion is
reversed, pawls are arranged at either end of the rack to drop into
the teeth of the pinion when it reverses and re-engage the rack with the
said pinion.
Both circuits may be maintained with one thermometer, provided it
be made large enough for both wires. By this second plan several
governors may be combined in one, thereby furnishing a machine
capable of regulating any number of rooms with the same accuracy
that the same number of single governors would.
Each room will be provided with its thermometers in electrical con-
nection with its cut-off and regulating valve, and each cut-off valve will
be worked by a rock arm of the same shaft.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 29th January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patant i cant cond crestine

page_text: Lord One thousand eight hundred and seventy-four, in the thirty-eighth
year of Her reign, did, for Пerself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special
licence that I, tho said Alexander Melville Clark, my executors, admini-
strators, and assigns, or such others as I, the said Alexander Melville
Clark, 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, öxercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN ELECTRO-MAGNETIC GOVERNORS FOR STEAK HEATING AND
DRYING APPARATUS," a communication to me from abroad by Julien
May Bradford, of Portland, in the County of Cumberland, and State
of Maine, United States of America, upon the condition (amongst
others) that I, the said Alexander Melville Clark, my executors or ad- :
ministrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain 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 Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the two accom-
panying Sheets of Drawings, and to the letters and figures marked
thercon (that is to say) :-
This Invention comprises an engine for working a cut-off valve and
a throttle valve of steam heating apparatus, with automatic apparatus
for opening and closing the valves, also for reversing and stopping and
starting the engine, the apparatus being controlled by electric currents
closed and broken by the variations of the heat through the medium of
thermometers in the heated room. The arrangement is adapted to
ensure a uniform temperature of any required degree.
The machine is designed for use in connection with drying and
heating rooms of all kinds and purposes. The motive power is in this
case obtained by means of a steam engino or engines, but when

page_text: action, and moreover, the different coils may be used for heating different
rooms, all being controlled by one regulator.
The cut-off valve is connected to the rod I which extends into the
valve chest of the steam engines, and is also connected to the reversing
valve K, so that whenever the cut-off valvo is cither opened or closed
the engines can be reversed to shift the regulating valve accordingly.
The steam enters chest J from pipo F at L through the stopping
and starting valvo M, which in practice will probably bo a balanced
valve; thence the steam passes along N into chamber ○ of tho
reversing valve, and when the cut-off valve in chamber C is opened,
and the reversing valve shifted to the left it enters the cylinders
through P, Q, R, and S, and exhausts through T, U, and V, and
when the cut-off valve is closed and the reversing valvo K is shifted
to the right, the steam enters through U and T, and exhausts through
S, R, Q, P, and V. In practice the valves in chamber T will bo:
arranged so as not to lift when steam enters through P, Q, R, and S.
These engines turn the crank shaft W, which by its pinion X turns
the wheel Y, which by its pinion Z turns the large wheel a from
which motion is obtained through the shaft to work the segmental
wheel d by a worm e; this segment is thus turned very slowly for
the purpose of working the regulating valve in chest D with which
it gears by the pinion F and rack 9 as slow as may be needed to
correspond as nearly as may be with the changes of temperature in the
dry house.
The crank shaft W has an eccentric which works a reciprocating
sleeve on the rod I by the rock shaft k, rods 1, and arms j. This.
sleevo slides freely on the rod, and it carries a pawl m which is
pivoted at p, and carries an armature 2 near the end next to the.
cut-off valve to be pulled down so as to catch collar when the valve
is to be closed by the electro-magnet r. It also has a springs for
pulling the other end down to catch collar when the cut-off is to
bo opened. A spring will be arranged under the segmental wheel
to cause it to engage with the worm for the reverse motion; after
having been turned to the extreme of its downward movement its
gravity will cause it to engage at the other extreme. Above the
pawl m is a small bar w which is insulated from the pawl box on
which it rests by a piece of vulcanized rubber. It carries a scrow

page_text: with a platinum point which touches a platinum disc when the pawl
is free from the magnet r, with which disc the binding screw y connects.
This bar also carries another binding screw. which with screw *
includes the pawl in the electrical circuit for controlling the stopping
5 and starting valve M, which is connected by its rod a' with the rock
shaft b' on which is a frame of soft iron c' carrying a magnet
supported by the arm g¹. Directly over this magnet is an armature.c¹
on a lever f¹ of a rock shaft ¹ in the axis of shaft 6', and connected
by the rod with a wrist pin on the pinion Z by which to obtain
O its motion. The magnetic frame is separated at e³ to cause the armaturo
to make the connection between the two poles by which its lifting
power is increased.
and
represent two thermometers which are supposed to be in
the room to be licated; is included in the circuit of the battery 1,
5 pawl m, and the magnet ď by the lines m³, n', and o'; and the steel
wire p',, is included in the battery A, and the magnet r by the
lines m³, q¹, and v', and the steel wire 8³. The wire p stands a little
lower than wire 81, and is supposed to indicate by its lower end the
degree of heat wanted.
When steam is let on by opening the cut-off valve, the regulating
valve being partly open and the engine in motion, the régulating
valve will gradually open till the heat rises to the required point,
when it should be open just enough to allow sufficient steam to pass
to maintain the heat thereat and then stop. The engine will then
be stopped to allow said valve to remain at rest by the closing of
the circuit through magnet d by the mercury touching the steel rod,
which will cause the frame c¹ to be attracted by the armature e',
and held so that when the lever f¹ is forced up by wheel Z the
frame c¹ will be drawn up with it, and will close the valve M which
is connected to its rock shaft. Should the heat then fall the circuit
will be broken by the mercury falling away from the steel rod p',
when the frame will fall away from lever f and set the engine
in motion to open the regulating valve still more. On the other
hand, should the heat continue to rise after the stopping of the regu-
lating valve, the mercury in thermometer will, by touching. steel
wire s', open the circuit through magnet r, which will pull down
pawl m, and also break the circuit through magnet-so that it will

page_text: fall and set the engine in motion, and the pawl will close the cut-off
valve and reverso the engine, which will close the regulating valvo
also and ensure the falling of the heat directly. As soon however
as it falls so that the circuit through magnet is broken, the pawl m
will be released by the magnet and pulled down by its spring against 5
collar n, so that it will open the cut-off valve and again reverso the
engine for again opening the regulator, and so on.
The regulating valve may be operated by the engine, or any other
driving gear, and reversed without reversing the engine or other driving
gear by the following method:-A magnet f* and a latch f' may be 1
fixed on the eccentric rod to connect or disconnect with the arm ƒ³
pivoted on the axis d³ of a wheel e³, according to whether the clectric
. current or the spring control the latch to work said arm or not (see
Figures 5, 6, 7, 8). The arm carries the double pawl to turn the
wheel e' which works the pinion fright or left, according to which
end of the pawl engages with the wheel, and this will be determined
by the position of the rod I of the cut-off valve by a little slotted
piece on said rod, into which a pin on the pawl projects, so that
when tho said valve is open and its rod I shifted to the left the
lower end of the pawl will engage the wheel, and when shifted the
other way the upper end will engage the wheel. In this caso tho-
mechanism for working the rod I will be the same in all respects
as in the other, except the rod 6³ connected to the sleeve i will be
worked by the rock shaft m², which is worked by an eccentric n³ on
the shaft o³, which is turned by the crank shaft.
The eccentric rod g', together with the above-described adjuncts,
aro shown in detail in Figure 8, and the rod is represented in a
vertical position, as it will probably be best to arrange it in practico.
When the current passes through the magnet f' from the thermo-
meter the latch will be pulled back and it will pass the lever ƒ³
without effect.
To allow the rack to be disengaged when moved to the end of its
range while the wheel e continues to move, and to be engaged again
when the motion of the wheel is reversed, the pawls p² are arranged
on the rack, as shown in Figure 7, to drop into the teeth of the pinion f
when it reverses. In this arrangement both the cut-off and regulating
yalvo are represented in chest D.

page_text: Both circuits may be maintained with one thermometer, provided it
be made large enough for both wires. By this second plan several
governors may be combined in one, thereby furnishing a machine
capable of regulating any number of rooms with the same accuracy
that the same number of single governors would.
Each room will be provided with its thermometers in electrical con-
nection with its cut-off and regulating valve, and each cut-off valve will
be worked by a rock arm of the shaft Mª.
'
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is,―
1st. The combination of an engine, a regulating valve, a reversing
engine, and mechanism for working the valve, and an electrical circuit
for controlling the reversing apparatus with the feed pipe of a steam
heating apparatus, and a thermometer in the heating chamber, sub-
stantially as specified.
2ndly. The combination of a cut-off valve with the regulating valve,
the reversing engine, electrical reversing circuit, feed pipe to the heating
apparatus, and a thermometer in the heating chamber, substantially as
specified.
3rdly. The combination of stopping and starting mechanism, substan-
tially as described, and an electrical circuit for controlling it with the
engine regulating valve, and a thermometer in the heating chamber,
substantially as specified.
4thly. The combination of the cut-off valve and reversing valve rod I,
collars t, n, pawl m, magnet r, armature q, and thermometer k¹, sub-
stantially as specified.
5thly. The combination of the circuit for controlling the stop valve
mechanism, with cut-off valve and reversing valve mechanism, sub-
stantially as specified.
6thly. The combination of the magnet d', lever g³, and armaturo
lever f, with the stopping and starting valve M, substantially as
specified.
7thly. The combination of a vibrating magnet f, and latch f³, also
lever f³, pawl b³, and spring f, with the wheel c³, and the cut-off
valve rod I for reversing the regulating valve in the manner described.

page_text: 8thly. The combination of the pawls p² with the rack g and the pinion f,
substantially as specified.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-eighth day of
January, in the year of our Lord One thousand eight hundred 5
and seventy-five.
"
Witness,
HY. SWALES,
. 53, Chancery Lane,
London.
A. M. CLARK. (L.S.)