US1597352A - Temperature-control apparatus - Google Patents

Description

Aug. 24 1926.

C.. L. FORTIER TEMPERATURE CONTROL APPARATUS Filed July 6, 1925 2 Sheets-Sheet 1 Aug. 24 1926.

c. L. FORTIER TEMPERATURE CONTROL APPARATUS Filed July 6, 1925 2 Sheets-Sheet g Patented Aug. 24, 1926.

UNITED STATES 1,597,352 PATENT OFFICE.

CHARLES L. FOR'I'IER, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO JOHNSON SERVICE COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

TEMPERATURE-CONTROL APPARATUS.

This invention pertains to so-called day .and night regulation and control of temperature in different rooms otta building, and particularly to maintenance of a constant normal temperature in selected rooms, and to the maintenance in other rooms of one temperature during hours of occupancy and of another temperature during hours of vacancy thereof. The invention resides in a novel method of and means for effecting from a central point, the setting or adjustment of the control instruments in the two sets of rooms, and particularly, in the employment for this 1 purpose of a special fluid pressure conduit independent of the customary fluid pressure main of the system, together with suitable valves, manipulation of which permits:

1. The setting of all control instruments to give constant normal temperature throughout the building;

2. The setting of the control instruments in selected rooms to maintain normal temperature, and of the control instruments in other rooms to give-during certain hours, a

relatively lower temperature;

. 3. The setting of the control instruments from a central point to cause a lowering. of

temperature in all rooms when the building is closed for the night; and finally,

4. The restoration from a central point, of all the control instruments to normal or daytime temperature adjustment when desired, regardless of the manual setting of the instruments in selected rooms.

Preliminary to setting the control instruments of selected rooms to give, alternately, higher and lower temperatures therein, said control instruments are manually set for 40 this purpose by means of a stop as heretofore, but once this adjustment is effected, the setting may be changed through manipulation of the valves at the control point, to give at will either the higher or the lower temperature as often as desired.

In the use of apparatus of this general character it has heretofore been customary, particularly in school buildings, to maintain the day temperature in selected rooms which are to be occupied both during the day and at night, the temperature in all other rooms being maintained during the night at a lower point. To this end, under former practice, it has been necessary to manually adjust the control instruments in those rooms in which difierent temperatures were to be. used during diflerent hours of the day, after which the change of setting necessary to bring about the change of temperature in such rooms was effected through manipulation of the air pressure in the main conduit. By the employment of a distinct and independent fluid pressure conduit for effecting the settin or change of adjustment of the contro instruments in the selected rooms, I avoid certain undesirable effects incident to the use of the single pressure main and its contained body of fluid under pressure, and secure a greater flexibility and certainty of control than has heretofore been attained.

The apparatus is illustrated more or less diagrammatically in Figure l of the drawing, in which there is shown a high pressure tank, a low pressure tank, a main air conduit, a secondary air conduit, a relay, and three identical thermostats each equipped with two selectors, the thermostats bemg shown respectively in right-hand side elevation partially sectioned, in face elevation, and in left-hand side elevation, each of said instruments being represented as placed in a separate room or apartment.

Flgure 2 shows in partially sectioned side elevation the right hand selector of Fig. 1, the relay, and the main heat valve, the selector being set for lower or night temperature, with its fluid pressure motor inflated and the thermostatic element moved outward from its normal or daytime adjustment.

By showing the thermostats in Fig. 1 from different viewpoints, the total number of figures required islessened.

In this drawing, Fig. 1, A indicates a 95 pressure fluid tank into which air is forced by a pump which automatically goes out of action when a pressure of (usually) fifteen pounds per square inch above atmospheric pressure is reached, and begins to operate again when the pressure 'falls below that point. B designates a similar tank connected with the tank A by a pipe into which is introduced a reducing valve C, which is forced and held open by the pressure in 105 tank A until a pressure of ten pounds per square inch above atmospheric pressure is produced in tank B, at which pressure valve C closes against further ingress of air. Tank A may hence be designated the high 119 at will with a pressure fluid main F, which communicates with one of each pair of selectors with which each thermostat or control instrument is equipped, and by which the setting of each is effected, as later explained. The pressure main F also communicates with the fluid pressure motor of each relay 2, of which there is one associated with each thermostat; the relays serving al-' ternately to admit pressure fluid to and to vent the fluid pressure motor 3 actuating the heat-control valve 4 of each radiator or other heater 5"included in the system, as is usual in pneumatic temperature control systems. Only one of the relays is shown connected up with the heat-control valve of a radiator in Fig; 1, but the pipe which establishesconnection between each thermostatand its relay is indicated for two of the control instruments shown in said figure. G designates a pipe communicating with low pressure tank B and, through the medium of a three-way valve H, with the independent pressure fluid pipe I communicating with the second selector of the pair belonging to each control instrument. By properly turning the plug or rotatable member of valve H, comunication may be established between the low pressure tank B and independent air-pipe I, or between said pipe I and the atmosphere, by way of vent J. The valvesE and H are, in practice, located in close proximity, so that they may be reached and manipulated by the janitor or attendant at a central point, and .-through their proper setting effect the setting or operation of the control instruments.

Intheir general construction and mode of operation the thermostat, the relay, and, the heat control element, are of the type used in the well-known Johnson system of temperature regulation, in which a very sensitive thermostatic element seals and unseals, according to variations in temperature, a minute vent, thereby causing fluid pressure to build up in a small diaphragm motor of the relay; and through said relay to admit L air into the pressure chamber of a heat-control valve, or to vent said chamber.

This places the final control of temperature upon the sensitive, practically frictionless thermostatic element, bringing into play a motor of adequate capacity to close and hold closed against the opening tendency of a spring, the larger heat-control valve. This general and the selectors with which each mechanism being well known and set forth in prior patents, will be somewhat briefly described, and merely to an extent sufficient to make clear the novel features of the present invention.

First describing the control instruments 1s equipped, each of said instruments comprises a back-plate or base of suitable form,- commonlysecured to a wall-plate set into and flush with the wall of the room in which it is used, a suitable cover or casing is conveniently formedonthe inner end of I a plug 11 screwed into the outer end of extension 6, said plug being provided with a tapped or threaded opening to receive an enlarged and threaded portion of a valvestem 12. The stem 12 also carries a disk 13, the outer face of which is diametrically divided, and the two parts painted or provided with contrasting colors, preferably white and black, indicating respectively, daytime and nighttime adjustment. The outer extremity of valve-stem 12 is made polygonal to facilitate turning by a suitable tool, which will enter through an opening in the outer casing (not shown). One half turn of stem 12 serves to reverse the colored sections of disk 13, and to bring either the black or the white half uppermost, where it may be seen through an opening in the casing, and thereby indicate the adjustment under which the instrument is at the time set to operate. Such half turn serves to carry valve 8 from one seat to the other, the seats thus limiting the turning of disk 13 in either direction, and insuring the full display of one colored section and covering of the other, under the respective adjustments. The disk 13 is represented in control instrument No. 2 of Figure 1 as under daytime or normal adjustment.

Extending forward from the front face of the back plate of each control instrument, near its lower end, are two arms 14 between which is pivoted a metal saddle or mount 15 carrying an upright thermostatic element 16, preferably formed of thin plates of brass and steel, soldered, riveted, or otherwise firmly joined face to'face, and adapted to warp or bend in one or the other direction according to rise or fall in the temperature of the surrounding medium. The metal in a nipple 18 projecting from the front of in the face the back-plate of the instrument, and communicating by a pipe 19 with the-fluid pres sure motor of the relay 2, later to be described. The. saddle tends naturally to fall by gravity, and being on the inner side of thermostatic bar 16, tendsto move the free end thereof toward the end of nipple 18. To support and maintain saddle 15 at such position that thermostatic bar 16 shall move to unseal and seal nipple 18 at a definite and predeterminedtemperature, or in the present case at either of two different temperatures, there are provided two levers 20 and 21 fulcrunied on a pivot-rod 22 eX- tending horizontally through three arms 23 projecting from the back-plate or base of each control instrument justbelow the arms 14. The outwardly extending short arm 24 of lever 20 carries an adjustablescrew-stop 26, which may be positioned to form a support for the saddle or mount 15. Lever 21 carries above its fulcrum a threaded stud 25 which extends laterally to a position to engage the inner or rear face of saddle or mount 15 and forms an adjustable .abutment therefor- The long upstanding arm of each lever 20 and 21 plays between two stops 28,

29 or 30, 31, either or both of which, inveach' pair, may be made adjustable, for which purpose they are preferably of screw form as shown. One stop of each pair is carried in the depending end of an overhanging bracket 32 or 33, while the other is seated of the back-plate of the instrument. t

Directly in rear of levers 20 and 21 are fluid pressure motors 34, 35 which may be of the flexible diaphragm, the sylphon bellows, or equivalenttype. The movable outer wall of motor 34 bears against a saucer plate 36 of lever 20, and the movable outer wall of motor 35 bears against a saucer plate 37 of lever 21, so that when either of said motors is inflated, it tends to press outward the upstanding arm of the lever in front of it. The lever's 20 and 21 are each pressed inward and urged toward their respective motors by a spring 38 or 39 encircling a stem 40" or 41. and compressed to the required degree by a nut 42 or 43 screwed upon the threaded outer ends of the stems 40 and 41. The left-hand motor 34 communicates with the main F by a branch F. and its lever 20 is hence normally pressed outward and held in contact with stop screw 29, thereby lowering stop-screw 26 away from the under side of saddle or mount 15. and leaving said saddle resting against and supported by stud 25 of lever 21. The lever is shown in this'position in control instrument No. 3, Fig. 1. In this adjustment the lever 20 compresses spring 38 which is ad justed to withstand without compression, under the pressures herein assumed, a pres sure materially less than 15 pounds. \Vhen valve H is turned to the position shown in Fig. 2, valve 8 is moved to its seat 10 and the right-hand motor 35 receives air from the secondary main I through a branch I and passage 1 the latter formed .in the back plate of the instrument as shown in control instrument No. 1,'Figs. 1 and 2, said motor 35 being vented through passage 44 when "alve 8 is on its seat 9, as also shown in said control instrument N o. 1, Fig. 1. Valve 8 is shown on its seat 9 in control instrument No. 1, Fig. 1 and on seat 10 in Fig. i

2. Spring 39 is compressed to withstand any pressure short of ten .pounds, but to yield when the pressure rises to or above that point.

The relay 2 above mentioned is shown in Figs. 1 and 2 between control instrument No. 1 and the main heat-control valve 4, and in its different adjustments in the two figures. A It is of the familiar type used in the ohnson system of temperature regulation, comprising a suitable back-plate from the front of which project arms 45 to which is fulcrunied at 46 a lever 47 carrying at its upper end abox-like head 48, and at its midlength a saucer plate 49 which rests against the movable wall of a fluid pressure motor 50 of the same character as motors 34 and 35 of the control instruments. The play of lever 47 is limited in both directions by the enlarged head of a screw-stem 51, the threaded end of which enters a tapped socket in the back-plate of relay 2,one side of the head extending into an opening 52 in one of the side bars of lever 47, as shown. A spring 53 exerts a constant pull tending to draw the upper end of lever 47 inward. In the position shown in Fig. 1 the diaphragm of motor 50 is inflated, extending spring 53.

In the top of the back-plate of the relay there-is formed a compressed air chamber 54 having an inlet port or passage 55 in communication with main F by a branch F The passage 55 is provided with a lateral branch 56 which passes downward to near the lower extremity of the back-plate, thence upward, and finally through the rear of said back-plate, where it communicates by pipe 19 with nipple 18 of control instrument No.

1, a lateral branch 57 of'passage 56 communileakage or escape of air very slight and gradual, or practically negligible so far as concerns the pressure in the main conduit. From the air chamber 54 at the top of the relay a port or passage 60 opens at the rear of the instrument, and communicates by a pipe 61 with the fluid pressure chamber of motor 3 of the main heat-control valve 4 which controls the supply of heating medium to the heater or radiator 5. 7

Within chamber 54 is a valve 62, shown in Figure 1 as sealing the inner end of port or passage 55, thereby precluding ingress of" air from branch pipe F to air chamber 54. The passage of air occurs by way of branch 56 to the chamber of motor 50 and to and through the port in nipple 18 when thermostat bar 16 is off its seat at the end of the nipple and the vent hence open. The stem 63 of valve 62 passes through a supporting and guiding block 64 screwed into a threaded seat and forming the outer wall of chamber 54, stem 63 carrying at its outer end a substantially spherical head 65 encompassed by a tensioned and consequently contractile annular spring 66 of helically coiled wire, the ends of which'are brought together and joined. This contractile annular spring lies between inner and outer walls of the box like head 48 of lever 47, between which walls it'has limited play, but against one or the other of which walls it normally rests, the

outer wall under the adjustment of parts shown in Figure 1.,

Under this construction, if the fluid pressure motor 50 be inflated, as it will be upon the closing of the vent or leak-port in'nipple 18 by inward movement of thermostatic bar 16 through fall of temperature, and as'it is shown sealedin Fig. 1, the upper end of lever 47 will be caused to move outward, and annular spring 66 will be forced over the high or equatorial section of head 65. By reason of the in herent tendency'of spring 66 to contract it will roll toward the outer wall of head 48, and resting thereagainst will exert an inward pressur on head 65, 'thereby,m0 v-ing inward said head, valve stem 63 and valve 62, thus seating said valve and closing the port or passage 55. When port 55 is closed, air will escape from motor 3 of main heat-control valve 4 by pipe 61 to chamber 54, and thence around the loose fitting valve stem 63 through plug 64 to the atmosphere, the return spring 67 of main heat-control valve 4 serving then to open said valve and admit steam or other heating medium to the radiator 5.

Thermostat strip is positioned so that a rise in temperatur tends to open the leak-port, and is adjusted for normal temperature (usually 70 degrees F ahr.) by

screw 30 when th diaphragm of motor 35' is collapsed. When said -motor 35 is inflated its lever 21 and saucer 37 are forced outward Or to the left, causing stud 25 to press outward the mount or saddle 15 and to move thermostat .strip 16 away from vent,nipple' 18, as in Fig. -2. The lower or night temperature (usually 40 to 50 degrees Fahr.), is determined by screw 31 when motor 35 is inflated. The left-hand selector of each control instrument is adjusted by screws 26 and 28 to give the lower or night the relay 2, through deflation of motor 56 and pull of spring 53, to withdraw or unseatvalve 62 and open passage 55, thus admitting air to chamber 54, and by way of pipe -61, to the fluid pressure chamber of motor 3, causing the seating of the main' heat valve and shutting off of the heating medium.

In rooms to be given normal temperature day and night, disk 13 is set to show the white surface, indicating daytime tempera ture, such adjustment causing valve 8 to move to its seat 9 and away from sea 10, thus shutting off ingress of airfrom ipe I, I', and venting motor 35 through port 44. In rooms which ar to have both day and night temperature, disk 13 is given a half turn to the left to show the darkened half indicating night temperature, --thus moving valve 8 from its seat 9 to seat 10, so as to admit air from pipe I, I to chamber 7 and thence to fluid pressure motor 35, inflating the same and moving the lever 21,

and consequently saddle 15 and thermo- To restore all the thermostats to daytime temperature setting, valve H is turned to the position shown in Fi 1, and air is exhausted from pipe I an branch I" and motor 35. When night session is over and it is desired to, maintain heat throughout the building at .a lower point, the janitor or attendant in charge turns valve E one-f quarter turn to the lefe,'closing the outlet of tank A and admitting the lower pressure from tank B to the system. The pressure will accordingly drop through the natural leaks in the instruments in use, motor 3t oft-he left-hand selector of each instrument will be. collapsed by its spring 38, screw 26 will engage saddle 15 withdrawing the thermostatic strip 16 from the nipple 18, and causing a lowering of temperature in all the rooms which had been occupied.

When it is desired to return the entire system to noraml or daytime operation, valves E and H are reset to the positions indicated in Fig. 1, the full or high pressure is thus restored to pipe F and its branches, and pipe I, its branches and the motors 35 with which pipe I communicates, are vented and the motors consequently deflated, leaving the whole system under normal control and operation.

The simplest way to lower the pressure is to lower it to atmospheric, but it is obviously not essential that any particular lower pressure be chosen. In using the word exhaust in certain of the claims I therefore use it in a general and not in a limiting sense.

lVhat is claimed is 1. A pneumatic temperature control sys-' tem, comprising a plurality of thermostats each having a leak-port and a thermostatic strip movable through temperature changes toward and from its sealing position against the leak-port nipple; asaddle or support for each thermostatic'strip, tending to carry said strip toward the leak-port nipple; two

independent fluid pressure motors associated with each saddle and thermostatic strip and each provided with a lever havmg a stud or projection to bear against and support the saddle at one or another predetermined adjustment as one or the other lever is moved tosaddle-supporting position; springs acting upon said levers and tending normally to. collapse the motors with which they are, respectively associated; adjustable stops to limit and determine the movement of said levers and the consequent adjustment of the saddle; and means for deflating the motor controlling one lever and inflating the motor controlling the other lever, both from a central point;

whereby the thermostatic strip is placed under control of either saddle ,sup ort at will and is, caused to maintain a re atively higher or a relatively lower temperature as desired.

2. A pneumatic temperature control system, comprising a plurality of thermostats each having a leak-port and a thermostatic strip movable through temperature changes toward and from its sealing position against the leak-port nipple; a saddle or support for each thermostatic strip tending to carry said strip toward the leak-port nipple; two independent fluid pressure motors associated with each saddle and thermostatic strip and each provided with a lever having a-stud or projection to bear against and support the saddle at one or another predetermined adjustment as one or the other lever is moved to saddle-supporting position; springs acting, upon said levers and tending normally to collapse the motors with which they are respectivey associated; adjustable stops to limit and determine the movement of said levers and the consequent adjustment of the saddle; an air main; a fluid pressure tank wherein is maintained a relatively high fluid pressure; a valve for establishing or cutting oil at will communication between said tank and main; a second main; a second tank wherein is maintained a relatively lower fluid pressure; a valve interposed between said second tank and main and serving'at will to establish communication between said tank and second main or to vent said second main to the atmosphere, the high pressure main communicating with one of the fluid pressure motors of the thermostatic instrument and the low pressure main communicating with the other fluid pressure motor of said" in strument; whereby through manipulation of the valves of the respective mains either motor may at will be placed under control of the fluid pressure or of its spring oppos-- ing said fluid pressure, and the saddle of the thermostat set to desired adjustment.

3. A pneumatic system of automatic temperature control, comprising a high pressure fluid main; 3 self-opening main heat valve; a fluid pressure motor for closing said valve; a relay containing a three-way valve for admitting air from the air main to the fluid pressure motor of the main heat valve or for venting said fluid pressure motor; a fluid pressure motor for actuating the relay to cut off communication between said air main and the motor 01,

the main heat-valve; a spring serving. to

operate the relay in a reverse direction to admit air to the heat valve motor; a vent nipple containing a leak-port for the relay motor; a thermostatic element for sealing and unsealing said leak-port; a pivotally mounted saddle or support carrying said thermostatic element and tending to move the sealing end of said element toward the leak-port nipple; two saddle supports each provided with means for independently adjusting the range of its movement; a spring normally tending so to position one of said supports that the thermostatic strip shall on fall of temperature to a predetermined point seal the leak-port; a fluid pressure motor connected with the high pressure fluid main and acting in opposition to said spring for moving said support away from the saddle, lowering said saddle, and permitting the thermostatic strip to move nearer to the leak-port nipple; a second and independent fluid pressure motor acting when inflated to force the saddle and the thermostatic strip carried thereby, outward or away from the leak-port nipple; a spring acting in opposition to said second fluid pressure motor and serving when said motor is deflated to move the second saddle support away from the saddle and to permit the latter to swing, inward and move the thermostatic element nearer to the vent nipple; an independent low pressure fluid main communicating with the fluid pressure motor of the second saddle support; a valve serving normally to vent said independent main to the atmosphere orto place it in communication with a source of fluid under relatively low pressure as compared with that of the high pressure main; a valve serving to connect and disconnect the high pressure main with or from a source of relatively high fluid pressure; and a manually adjustable valve serving, according to adjustment, to admit fluid from the independent main to the last-mentioned fluid pressure motor or to vent said motor to the atmosphere.

4. An automatic temperature control system of the pneumatic relay type, comprising in addition to the usual heat-control valy es, relays, and thermostats, a main conduit and a secondary conduit, two independently adjustable stops for positioning and maintaining the saddle or support of the thermostatic element in each thermostatic instrument at either normal daytime temperature saddle support in a direction to carry the thermostatic element away from the leakport nipple of its associated thermostat; a spring acting in opposition to said second motor and tending to move said second saddle support away from the saddle; a manually adjustable valve serving in one adjustment to admit air from the secondary conduit to the second fluid pressure motor, or in opposite adjustment to shut off communication between said motor and secondary conduit and vent the motor to the atmosphere; and two valves located in proximity to each other, one in the main conduit serving to shut off communication between said main conduit andits source of high fluid pressure, the other in the secondary pressure motor of its associated relay; a

saddle or support pivoted to said base; a thermostatic element carried by said support and movable at its free end to and from sealing relation to the vent nipple; a lever 'fulcrumed on said base and provided with a screw serving as a support for the saddle; stop screws to limit and determine the play of said lever and the consequent play of its saddle support; a spring tending to move said lever and its saddle support to saddlesupporting position; a fluid pressure motor in communication with said main conduit and acting when inflated to force said lever in opposition to said spring and to carry its saddle support away from the saddle; a second lever fulcrumed to the base and provided with a saddle support movable toward and from the saddle; a spring serving normally to press said second lever and saddle support away from the saddle; a fluid pressure motor communicating with the secondary conduit and serving when inflated to force said lever and its saddle support outward against the resistance of said spring,

--and to move the free end of the thermostatic element away from. the leak-port; a manually adjustable valve carried by the thermostatic instrument and serving, according to adjustment to admit fluid pressure from the secondary conduit to said second motor or to vent said motor to the atmos- .phere; a valve whereby admission of pressurefluid to the main conduit may be established or cut off at will; and a valve whereby low pressure fluid may be admitted to the secondary conduit or said conduit may be disconnected from the fluid pressure source and vented to the atmosphere.

6. A control system of the character described, comprising a fluid-pressure conduit embracing a plurality of instruments each having a leak-port; a themostatic element associated with each such instrument and movable through temperature changes toward and from sealing position against said leak-port, to effect the operation of a main control valve; a mount for each thermostatic element tending to carry said element toward its associated leak-port; a springopposed fluid pressure motor on each instrument in operative relation to each said mount, and provided with adjustable means to bear against and support said mount at one or another predetermined adjustment; a conduit independent of said first-named conduit. embracing all said motors and communicating with a fluid-pressure supply; and means for admitting fluid under pressure to said independent conduit and motors and for exhausting such fluid pressure, at will.

7. A control system of the compressed air type, comprising a fluid-pressure conduit embracing a plurality of instruments each having an adjustable thermostatic element movable through temperature changes to effect the operation of a main control valve; a fluid pressure motor on each instrument provided with means to vary the adjustment of said thermostatic element to one or another predetermined degree; a conduit independent of said first-mentioned conduit, embracing all of said motors and communicating with a fluid-pressure supply; and means for admitting fluid under pressure to said independent conduit and motors and for exhausting such fluid pressure at will.

8. In a day and night thermostat, the combi nation of a temperature-controlling thermostatic unit; power actuated means operable at will to adjust said unit alternately to maintain either of two diflerent temperatures; and a second power actuated adjusting means operable at will to impose a definite adjustment on said thermostatic unit regardless of the action of the first named adjusting means.

9. The combination of a temperature-regulating thermostat; power actuated adjusting means for shifting said thermostat between two settings; a second power-actuated adjusting means for maintaining one of said two settings regardless of the action of the first named adjusting means; and manually operable means adjacent thethermostat, for preventing the actuation of one of said adjusting means.

10. A control system of the compressed-air type, comprising a fluid-pressure conduit embracing a plurality of instruments each having a thermostatic element movable through temperature changes to effect the operation of a main controlvalve; pneumatic means associated with each thermostatic element and provided with means for varying the adjustment of said element to one or another predetermined degree; a second conduit independent of said first-mentioned conduit, embracing all of said pneumatic means and communicating with a fluid-pressure supply, whereby when fluid pressure is admitted to said second conduit and said pneumatic means the thermostatic element will function at one temperature and when said second conduit and said pneumatic means are exhausted of pressure said element will function at a different temperature; and means for admitting fluid pres sure to said second conduit and said pneumatic means and for exhausting said fluid pressure, at will.

11. A control system of the compresseda1r type, comprising a fluid pressure conduit embracing a plurality of instruments each having thermostatic means movable through temperature changes to efl ect the operation of a main control valve; pneumatic means associated with each instrument and pro' vided with means for varying the operative adjustment of said instruments, to one or another predetermined degree; manual means associated with each of said instruments for preventing the operation of said pneumatic means, as desired; a second conduit independent of said firstmentioned conduit, embracing all of said pneumatic means and communicating with a fluid pressure supply, whereby when fluid pres sure is admitted to said second conduitand said pneumatic means the instruments which are not prevented by the manual means will function at one temperature, and when said second conduit and said pneumatic means are exhausted of pressure said instruments will function at a different tempen ature; and means for admitting fluid under pressure to said second conduit and said pneumatic means, and for exhausting said pressure. at will.

12. The combination of a fluid pressure thermostat having an adjustable temperatureresponsive element and a fluid-pressure supply line; two pressure actuated means for adjusting said element, one of'which is subject to the pressure in said supply line. at least one of said adjusting means being capable of suspending the effect of the other; means for varying the pressure on thesupply line to eflect adjustment of the responsive element by the adjusting means subject to such pressure; and a device constructed and arranged to exert a controlling pressure on the other adjusting means.

13. The combination of a fluid pressure thermostat having an adjustable temperature-responsive element and a fluid pressure supply line; two pressure actuated means for adjusting said element, one of which is subject to .the pressure in said supply line, at least one of said adjusting means being capable of suspending the effect of the other; means for varying the pressure on the supply line to effect adjustment of the responsive element by the adjusting means sub ject to such pressure: a device constructed and ar'ranged to exert a controlling pressure on the other adjusting means; and manually operable means for cutting one of said adjusting means out of action.

14. The combination with a temperature regulating system including a plurality of fluid-pressure thermostats, heating means controlled individually by the various therniostats, and a fluid pressure supply line; of pressure actuated adjusting means for adjusting such thermostats as a group; a second pressure actuated adjusting means operatively related with said thermostats and capable of effecting an adjustment thereof independent of the action of the first-named adjusting means; a selecting device adjacent each thermostat for rendering the secondnamed adjusting means operative or inoperative; means for admitting and releasing pressure fluid to and fromsaid second named mostats, and a fluid pressure supply line; of pressure actuated adjusting means subject to the pressure in said supply line and operable by variations of such pressure to adjust such thermostats as a group; a second pressure actuated adjusting means opertively related with said thermostats and capable of effecting an adjustment thereof independent of the action of the first-named adjusting means; a selecting device adjacent each thermostat for rendering the secondnamed adjusting means operative or inoperative; means for admitting and releasing pressure fluid to and from said second-' named adjusting means; and means for varying the pressure on said supply line.

In testimony whereof I have signed my name to this specification.

CHARLES L. FORTIER.

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