Improvements in Thermostats or Instruments for Regulating Temperatures.
Year: 1891

page_text: Date of Application, 24th Nov., 1891
Complete Specification Left, 18th June, 1892-Accepied, 23rd. July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Thermostats or Instruments for Regulating
Temperatures.
1, ALEXANDER SHIELS of 190 Bath Street, Glasgow, M.B., C.M., B.Sc., do
hereby declare the nature of this invention to be as follows:-
This invention relates to thermostats or instruments for regulating temperatures.
The invention is principally designed for use in regulating the temperature of
refrigerating chambers for meat &c.
In the present invention which is a further development of my prior inventions
Nos. 6035 of 1891 and 18449 of 1891 the valve for supplying steain to the engines
or refrigerating fluid to the meat chamber is operated by means of a long lever,
The lever is,
which may be single or double, having a long groove or slot in it.
preferably, near the lower end bent to or nearly to a right-angle. The end of the
bent part is pinned or connected to a link or lever, which may be bent, and which
is connected to and operates the valve. The upper end of the long slotted or
grooved lever is connected by a swing link or rod to the framing or other suitable
part. In the slot or groove of the lever a pin or projection on the piston-rod of
the thermostat works. The long lever is counterbalanced by a weight.
When the piston rod of the thermostat rises, the pin or projection moves in the
slot, and, at the same time, owing to the bent form of the lever, lifts it up and so
operates the valve. When the valve is fully opened the pin simply travels up the
straight part of the lever without moving the valve further.
In cases where the temperature in the refrigerating chamber, through an accident,
rises far above the normal the piston rod of the thermostat or a projection on it
may be made to strike a lever and open a valve leading to the sensitive fluid tank
so that the excess of fluid in the pipes may pass into the tank and thus prevent
breakage or bursting of the apparatus.
To give a steady movement to the piston and to bring it down when contraction
takes place in the fluid in the thermostat tubes, a spring may be fitted to the
apparatus and be connected to the piston rod by multiplying pulleys so as to allow
a big travel of the piston.
Instead of using mercury as formerly in the syphon of the thermostat any other
suitable fluid may be substituted or the sensitive fluid may be made to act directly
on the piston.
1001
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.
COMPLETE SPECIFICATION.
Improvements in Thermostats or Instruments for Regulating
Temperatures.
I, ALEXANDER SHIELS, of 190 Bath Street, Glasgow, M.B., C.M., B.Sc., do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to thermostats, or instruments for regulating temperatures.
The invention is principally designed for use in regulating the temperature of
refrigerating chambers for meat etc.
In the present invention, which is a further development of my prior inventions,
Nos. 6035 of 1891, and 18449 of 1891 the valve for supplying steam to the engines
T

page_text: or refrigerating fluid to the meat chamber is operated by means of a long lever,
which may be single or double, having a long groove or slot in it. The lever is,
preferably, near the lower end bent to or nearly to a right-angle. The end of the
bent part is pinned or connected to a link or lever, which may be bent, and which
is connected to and operates the valve. The upper end of the long slotted or
grooved lever is connected, by a swing link or rod to the framing or other suitable
part. In the slot or groove of the lever a pin or projection, on the piston-rod of
the thermostat works. The long lever is counterbalanced by a weight.
When the piston. rod of the thermostat rises, the pin or projection moves in the
slot, and, at the same time, owing to the bent form of the lever, lifts it up and so
operates the valve.
In cases where the temperature in the refrigerating chamber, throughran accident,
rises far above the normal the piston rod of the thermostat or a projection on it
may be made to strike a lever and open a valve leading to the sensitive fluid tank
so that the excess of fluid in the pipes may pass into the tank and thus prevent
breakage or bursting of the apparatus.
±
To give a steady movement to the piston and to bring it down when contraction
takes place in the fluid in the thermostat tubes, a spring may be fitted to the
apparatus and be connected to the piston rod by multiplying pulleys so as to allow
a big travel of the piston.
Instead of using mercury as formerly in the syphon of the thermostat any other
suitable fluid may be substituted or the sensitive fluid may be made to act directly
on the piston.
And in order that my said invention may be properly understood, I have here-
anto appended an explanatory sheet of drawings, whereon:-
Fig. 1 is a part vertical section of the thermostat.
Fig. 2 is a cross section on the line -, Fig. 1.
Fig. 3 is an end view of the thermostat.
Fig. 4 is an end view of a modified arrangement.
Fig. 5 is a sectional plan on the line y-y, Fig. 4.
Fig. 6 is a plan view of the weight, attached to the top of the piston rod.
Fig. 7 is a part vertical section to an enlarged scale.
Fig. 8 is a sectional plan of Fig. 7 on line A-A.
Fig.,9 is an enlarged sectional detail.
Referring to the drawings, whereon the same reference numerals, wherever
repeated, indicate similar or like parts.
1 is a glass or metal tube, which is fitted at its lower end into a casting 2, which
latter has a flange 2" on it, and is secured in any suitable position. The casting 2
has a cored out channel or passage way 3 in it. The tube 1 fits into the casting at
one end of the passage way, whilst a second tube 4 fits into the casting at the other
end of the passage way. The casting; together with the tubes 1 and 4, makes a
Uor syphon-shaped receptacle, into which mercury 5, or other suitable fluid, is
placed. The tubes 1 & 4 pass up through a bracket 6, which is secured to the wall
or other suitable place. The casting 2 may be braced to the bracket 6 by a
screw 3ª. The tube 4 is or may be held. in place in the bracket 6, by means of a
screwed nipple 7, which, if the tube 4 is of glass, is cemented to the tube. The
nipple is screwed through the bracket 6' and securely held in place by a nut 8.
The tube 1 is or may be held in place by a long nipple or sleeve 9, screwed on or
cemented to it, and a jam nut 10. The tube 1'lias coupled to it, at its upper end,
a pipe which is connected with the sensitive fluid pipes arranged in the interior
of the chamber the temperature of which is torbe regulated: The sensitive: fluid
pipes may be the same as those described in the Specification of my-prior:Patent
No. 6035 of 1891. The coupling for connecting, together, the pipe 11 and tube 1
may also be the same as that described, in my prior, Patent No. 18449 of 1891.
12 is a nut for securing the coupling. 13 is a sensitivo Huid. tank.. which is con-
nected by the junction pipe 14 with the pipe 115.is.a cock on the pipe 114.
"16 is the lever handle of the cock.17 is a link which is pinned, at one end to the

page_text: lever 18 and at the end to the lever handle 16. The lever 18 is 'fulcrumed at 19.
A link 20 connects the short arm of the lever 18 with the lower end of a vertically
sliding bar 21. The bar 21 slides in the guide brackets 22, 23. 24 is an adjustable
stop fitted on the bar 21. The sensitive fluid tank 13 may be provided with the
asual filler 25 and cock:26.
In the tube 4 works a piston 27, the piston rod, 28, of which has at its upper
end a weight 29. The weight 29 is shown in plan view at Fig. 6. The weight
has cuts or recesses 30, 31 in its sides which slide on the ribs 32 of the tee irons 33
(see Figs. 2 & 3). The side ribs 32 steady the weight as it rises and falls. The
tee shaped guide bars 33 are fitted at each side of the apparatus as shown at
Fig. 3.
The bars are secured together at their upper ends by a bridge 34. The
bars at their lower ends are bolted by the bolts 35 to the bracket 6. The weight 29
has also recesses 68, 68 through which the guide levers 45, 45 pass.
Fitted on the bracket 6 are two bearings 36, 37 in which is carried a hollow
sleeve or liner 38. Inside the liner is a horizontal shaft 39. The liner may be
pinned to the shaft by a screw 40 (see Figs. 7 and 8). By unscrewing the screw 40
at any time the shaft 39 can be withdrawn. Mounted on and secured to the liner
is a double bent lever 41, 41. On the double lever 41 is an adjustable weight 42
the position of which can be altered by means of the screw 42ª. The weight 42
counterbalances the weight of the levers 45, 45. 43 is a bridge connecting the
two parts of the double lever 41. 44, 44 are links which connect the straight.
ends of the lever 41 to the lower bent ends of the two vertical guide levers 45.
46, 46 are slots made in the links 44, 44. 47, 47 are studs which project through
the slots 46, 46 and secure the links 44, 44 to the arms 41 of the bent lever. The
slots 46 are made in the links 44 for the purpose of allowing said links to be
adjusted longitudinally. The links 44 are secured to the guide levers 45 by a
cross bar 48 (see Figs. 8 and 2). The vertical guide levers 45, 45 have long
slots 49, 49 in them. The slots 49 are, as shown at Figs. 1 & 7, curved at their
lower ends. 50 are small cross bars for strengthening the guide levers. They
are bent as shown in plan view at Fig. 3. The upper ends of the guide
levers 45, 45 are connected by two links 51, 51 to two arms 52, 52 pivotally
secured on a projecting bar 53. The bar 53 is attached to or made one with
a plate 54 secured to the wall. The arms 52 may be fitted on, or connected
together by, a sleeve 55 which is free to move loosely on said projecting bar 53.
The arms 52 bave slots 56, 56 in them (see dotted lines Fig. 1 where one of the
slots is shown the slot on the other arm 52 does not appear on the drawings).
57 is a pin for securing the link 51 to the pivotted arm 52. By means of the
slots 56 and pins 57 the length of the links 51 can be altered.
On the piston rod 28 is a cross bar 58 (shown to a larger scale at Figs. 7 & 8).
The cross bar 58 is secured to the piston rod 28 by the pin 59. Projecting from
cach side of the cross bar 58 are arms 60 on which (see Fig. 9) are small rollers 61.
The arms 60 project through the slots 49, 49 of the guide levers 45. The small
rollers 61 run in the slots of said guide levers. On the weight 29 is a small
circuit closer 62. A projection 63 is also made on said weight 29.
64, 65 are two small spring contacts connected by wires to the poles of a battery.
The wires include in their circuit an electric bell placed in the engine room or
Fother place to sound an alarm. 66, 66 are two cords, which are attached to the
cross bar 58 and to a spring or weight which is not shown. The cords 66, 66. run
over guide pulleys 67, 68. The shaft 39 is so connected by any suitable arrange-
ment to the valve or valves for turning on the steam or other fluid pressure supply
to the engines which drive the refrigerating machinery, or to the valve or valves
for supplying the. refrigerating fluid to the chamber, that, when said shaft 39 is
turned, the steam or other fluid pressure or the refrigerating fluid supply, as the
case may be, is regulated and controlled. The apparatus for effecting this may
be the same as any of those described in the Specification of my prior Patent
No. 18,449 of 1891, or any other suitable device.
The action of the apparatus is as follows:-When the temperature rises within

page_text: the chamber, the expansion of the sensitive fluid in the sensitive fluid pipes and in
the pipe 11 exerts pressure on and forces, down the mercury in the tube 1, and,
consequently, forces up the piston 27,. against the action of the weight 29 and the
spring or weight attached to the cords 66. The rising of the piston causes the
rollers 61, on the arms 60 of the cross-piece 58, to travel along the lower curved
part of the slots 49, 49, and, as a consequence, from the shape of the slots,. to
eventually lift or raise the guide levers 45, 45, by a parallel movement to the position
shown in dotted lines at Fig. 7. The swing links 51 and 44 allow the parallel
motion of the guide, levers to take place. The raising of the guide levers, causes,
The moving
at the same time, the bent lever 41, 41, to be moved through an arc.
of the bent lever 41, 41, turns the shaft 39, and so operates the valve or valves for
turning on a supply of steam to the refrigerating engines, or, as the case may
be, a further supply of refrigerating fluid to the chamber or room.
If it is desired to maintain a low temperature, say about 32 degrees Fahrenheit
in the refrigerating chamber, so as to refrigerate meat, the valve or valves
regulating the supply of steam to the refrigerating engine, or the refrigerating
fluid to the chamber, is or are so arranged. relatively with the thermostat, that,
when the guide levers 45, 45, are in the position shown in full lines at Fig. 7, the
supply valve or valves is or are nearly shut, while the temperature within the
chamber is at, say, about 31 degrees Fahrenheit. When the guide levers 45
attain the position shown in dotted lines at Fig. 7, the supply valves are wide open,
and allow a full supply of steam or fluid, as the case may be. The apparatus is
likewise so arranged that, when the guide levers have attained this position, the
temperature within the chamber would have risen to, say, about 33 degrees
Fahrenheit. By this arrangement, therefore, a rise or fall of about 3 degrees, is
sufficient to alter the conditions, from a very little to a full supply of steam or
refrigerating fluid. But, as the supply valves are nearly closed at the 31° position,
there would not be a sufficient steam or fluid supply to maintain the low tem-
perature, and, as the valves are fully open at the 33° position, the supply of steami
or fluid would then be more than sufficient to maintain the temperature of that
position (ie. would cause the temperature to fall), then, as a consequence, the
thermostat would find a normal position, somewhere between these extremes, at
which the openness
"of the supply valves suited the maintenance of the tem-
perature desired in the chamber." That position might be one in which the
temperature was either slightly above 32° F. or slightly below 32°. F., but,
practically, the thermostat would be found to take up a position somewhere about
the mean between the two extreme positions, and would oscillate slightly above and
below that mean. In this way, a temperature of no great variance would be main-
tained in the chamber. The above takes place so long as the refrigerator and
refrigerating machine are in proper working order, and the supply of steam etc. is
maintained.
..
If, however, say, at any time during a voyage, the supply of steam to the
refrigerating engine was cut off, or the supply of refrigerating fluid to the chamber
stopped, or if, in any way, the refrigerating power of the machinery was interfered
.with, the thermostat would act as follows:-If the refrigerating power was
increased, so as to lower the temperature too much, then the piston and guide levers
would sink to the position shown in Fig. 1, and close the supply valves, con
sequently, the temperature of the chamber would gradually rise again. But if,
on the other hand, the refrigerating power of the engines was decreased to such
an extent as not to be able to maintain the necessary low temperature within the
chamber, then the guide levers would pass into the dotted position Fig. 7, and
turn the supply valves full on. Should the temperature within the chamber, in
spite of the full supply of steam or fluid, still continue to rise, then, the piston 27
would rise also, and the rollers 61 on the cross-bar 58, would travel out of the
lower curved part of the slots 49, and up the long straight parts of the slots in the
guide levers, and when a temperature (say 35° F.) was nearly reached that would
cause the meat to begin to deteriorate, the circuit closer 62 on the weight 29,

page_text: would close the circuit between the contacts 64 and 65, and ring an alarm bell in
the engine room or elsewhere, so that the engineer would at once be notified of the
dangerous position of matters within the refrigerating chamber, and that the supply
of steam or refrigerating fluid should be attended to. As soon as the supply' was
attended to the thermostat would return again to its normal position. The con-
tacts 64 and 65 are so arranged relatively with the rest of the apparatus that when
the circuit is closed by the armature or circuit-closer 62 the temperature within the
chamber is about 35°.
When the chamber is not being used as a refrigerator or when it is out of use,
as, for instance on the return voyage of a ship, it is not necessary that a low
temperature should be maintained within the chamber and the refrigerating engines
need not be used. In such cases the temperature within the chamber will naturally
rise until it is the same as the surrounding atmosphere. As the temperature rises
within the chamber, the rollers 61 gradually pass out of the lower curved parts of
the slots 49, and move up the long straight parts, where they oscillate up and
down, according to the variations of temperature within the chamber. The slots 49
are made long enough to allow of any degree of expansion of the sensitive fluid
due to the ordinary conditions of outside temperature. When refrigeration is
again carried on within the chamber, all that requires to be done is to turn on the
supply of steam, or refrigerating fluid, as the case may be, and, as the temperature
within the chamber falls, the rollers 61 and piston 27 will fall in unison therewith,
until the rollers come within the lower curved parts of the slots 49, which is their
normal refrigerating position.
The instrument is automatic under such conditions.
When, from any abnormal cause, the temperature within the chamber rises above
the limits allowed for, the rollers 61, 61, will travel right up to the top of the
slots 49, 49, of the guide levers 45, 45. Before the rollers reach the top of the
slots, however, the projection 63 on the weight 29, strikes against the adjustable
stop or projection 24, on the bar 21, and lifts it and the bar upwards. The raising
of the bar 21, turns the lever 18 on its fulcrum 19, and, at the same time, in con-
sequence, forces down the handle 16 of the cock or safety valve 15. The excess
of sensitive-fluid pressure can now pass into the chamber 13, instead of, as would
otherwise be the case, forcing the piston 27 up to such a height that the rollers 61
would jam against the top of the slots 49, which would probably result in the
breaking or damaging of the instrument. When the instrument has been subjected
to such an abnormal increase of temperature, it has to be reset, in order to
maintain the particular temperature desired within the chamber.
When at any time the temperature falls within the refrigerating chamber or
room, and, as a consequence, the sensitive fluid within the fluid pipes and pipe 11
contracts, the action of the weight 29 and of the spring or weight attached to
the cords 66, causes the piston 27 to rapidly sink within the tube 4 and, con-
sequently, close the supply valves.
Under a modification, as shown at Figs. 4 and 5, the weight 29 and cross-bar 58,
may have holes 70, through which guide bars 71, 71, pass. These guide bars, 71, 71,
serve instead of the tee-shaped guide bars 33, 33, of Figs. 1, 2 and 3. In this
case, the guide levers 45, 45, are outside of the guide bars 71, 71, and the cross-
piece 58 is made longer, see Fig. 5, so that the rollers 61, on the arms 60, 60, may
pass through the slots in said guide bars.
Instead of the guide levers 45 having slots to guide the arms 60, they have
grooves for this purpose.
The apparatus may be modified in its construction, without departing from the
principle of the invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The general arrangement and combination of marts of the improved

page_text: thermostat, substantially as hereinbefore described, with reference to the drawings
-annexed.
2. In a thermostat, a guide lever (or levers) having a slot or groove, or slots or
grooves, along which a projection (or projections), on the piston rod, slides, said
guide lever (or levers) having a parallel movement, substantially as hereinbefore
described with reference to the drawings annexed.
3. The combination of the bent levers 41, or their equivalent, the links 44, the
guide levers 45, and the swing links 51, or their equivalent, substantially as herein-
before described and shown on the drawings annexed.
4. The combination with the improved thermostat, of the device for opening the
safety valve 15, consisting of a projection 63 on the weight 29, the adjustable.
projection 24 on the bar 21, link 20, lever 18 and link 17, substantially as herein-
before described and shown on the drawings annexed.
Dated this 17th day of June 1892.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.