USRE21154E - Summeb-winteh air conditioning - Google Patents

Description

July 18, y1939. G. D. KINGsLAND "INNER- WINTER AIR CONDITIONING SYSTEM Original Filed June 6, 1934 (3M/vento@ George D. Kingsland Ressued July 18, 1939 vUNITED STATES PATENT OFFICE 21,154 SUMMER-WINTER AIR CONDITIO'NNG Y SYSTEM George D. Kingsland, 'Minneapolis Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Original No. 2,123,428, dated July 12, 1938, Serial A No. 729,253, June 6, 1934. Application for re- 48 Claims.

is the provision of a temperature control system for maintaining the temperature of a buildingl or space at a desired temperature' or within a desired temperature range during the entire year in which a minimum number of controls is utilized and in which a minimum number of manual operations are required to change the system from its winter automatic heating operation to its summer automatic cooling operation.

A further object of theinv'ention is the provision oi' a cooling system wherein a large supply of outside airis furnished to the building or space when the temperature of the outside air is approximately that desired within the space or building, the supply of outside lair being decreased as the temperature of the outside air rises above or falls below the desired inside temperature, together with cooling means' which is controlled in accordance with fluctuating of the building or space temperature in order to maintain the building or space temperature at the desired value or within given limits.

A further objectof the invention is the provision of a cooling system in which there is provided a large supply of fresh outside air vwhen the outside temperature is about-that desired in the space or building, decreasing the supply of outside air as the outside temperature rises and operating a cooling means to maintain the space 'temperature at the desired point and alsodecreasing the supply of outside air as the outside temperature falls below the desired building or space temperature and rendering the cooling means inoperative when .the outside air temperature falls below some minimum value.

A further object of Vthe invention is thel provision oi a cooling system in which a variable amount of .outside fresh air is supplied to the space or building to be cooled as the temperature of the outside air rises until a predetermined minimum amount of outside air is being supplied 50 to the space orabuilding and then maintaining this predetermined minimum supply of outside air upon further rise in outside temperaturel so that there will always be a minimumsupply of fresh air for Ventilating purposes and thereafter 56 totally discontinuing the supply of fresh outside issue May 20, 1939, Serial No. 274,850

air in the event the outside temperature becomes excessively high.

A further object of the invention is the provision of a cooling system in which a cooling means is v normally operated in accordance with iluctuations in the temperature of the space or building to be cooled in order to maintain the temperature thereof at a'desired point or within desired 'limits and additionally operating the cooling means even though the space temperature is at the desired point rl'within the desired limits provided the relative humidity of the air in the space reachesl a predetermined maximum value.

Another obJect of the invention is the provision of a heating system for maintaining the temperature of a space or building at a desired point or within desired limits, together with means for supplying a variable amount of fresh outside air to the space or building in -the event the temperature thereof becomes excessive or appreaches the permissible high limit. the arrange- ,ment preferably being such that whenever cold outside airis being supplied to the space or building no heat is being supplied thereto and that when heat is being supplied to the space or building no outside fresh air is being supplied thereto. In thepreferred form of this phase of the invention, means are further provided for preventing the relative humidity from falling bevlow a predetermined minimum value.

A further object of the invention is the provision of a heating and cooling system for a space or building whereby the space is automatically heated in the winter and automatically cooled' when necessary in the summer, together with manually operable means for furnishing a complete supply of outdoor air inv order to quickly ventilate the space being controlled irrespective of whether the system is operating on a heading or a cooling cycle. I

Another object of the invention is the .provision 'of a single manual master control by means of Awhich the system can be rendered entirely inoperative by a single operation irrespective of whether the system is being operated on the winter cycle or on the summer cycle.

In the preferred form ofthe invention. the automatic control system is entirely electrical and'automatic both for summer and winter operation and in order to change overfrom summer -to winter operationl it is only necessary to oper- `ate a reversing switch and to make one or two simple mechanical adjustments.

Further objects of the invention. will be found in the detailed description, the drawing, and the appended claims.

For a more complete understanding of the invention, reference may be had to the following description and accompanying drawing in which,

Fig. l is a diagrammatic showing of the'comkplete control system and the manner in which it is associated with the heating and cooling means, the parts being shown adjusted for summer operation, and,

Fig. 2 is an enlarged schematic showing of one 4of the controllers used in the system of the present invention when operating on the summer cycle.

and` Ventilating mechanism is illustrated-as comprising an voutside air duct III which is in communication with the outside atmosphere, a return air duct Il which communicates with the space or building to be controlled, and a heating and cooling chamber or duct I2, one'end of which communicates with the outside atmosphere and return air ducts I0 and l I respectively and the other end of which communicates with the space or building to be controlled. Located within'the chamber or duct I2 is an electrically operated fan or blower I3 by means of which air is supplied to the space or building, the air being drawn through the chamber I2 and the outside air duct Ill and/or the return air duct I I. This chamber I2 is preferably provided with air filters I4 ofv usual construction for cleansing'the air delivered to the space or building to be controlled.

A cooling system is herein shownas comprising a. compressor I5 which is driven by an electric motor Il, the compressor being connected to a cooling coil I1 located Within the chamber I2 through the usual condenser I8 and mechanical expansion valve I3. Such cooling systems are well-known in the art and no further explanation thereo is thought necessary herein, it being noted that whenever compressor motor I6 is energized, the cooling coil- I1 wil b e conditioned to cool the air passing thereover and when the compressor motorY I5 is deenergized, the cooling coils I1 will no longer operate to provide further substantial cooling.

' The heating system is shown as comprising heating coils v28 located vwithin-chamber I2 and connected by a pipe 2| to the usual' return line or discharge.-v The heating coils 20 connected to a proportioning steanivalve, generally indicated at 22 by ymeans of a pipe 23. In this particular embodimentofthe invention, it is assumed that the steamI is supplied-from a central or district supply station through a pipe 24 but it will be `appreciated that, the supply of steam could be obtained from'a steam boiler located in the building itself. The pipe 24 is connected to an electrically operable-two-position steam valve 25 by means of which the supply of steam may be com-` pletely turned on or oi and this electricallyop.- erable two-position steam valve 25 is connected to modulating or proportioning steam Valve 22 by means of a pipe 25, the pipe 28 preferably including a manuallyoperable shut-olf valve 21.

The means for preventing the relative humidity 'from falling below a predetermined minimum value"during the winter is herein shown as comprising a water spray 28 located in chamber I2 in front of heating coils 2li. This water spray 28 is connected to a water supply pipe 29 through an electrically operable water valve 30. l

Located Within the outside air duct III is a Referring to the drawing, the heating, cooling amount of outside air may be drawn through outside air duct I9, the maximum supply of outside air being obtainable` when the dampers are in the position shown wherein each of the'dampers 3l and 32 is equally displaced from a vertical position.

A single motorized operating mechanism, generally indicated at 34, is utilized to control the dampers 3| and 32 and the modulating or pro-` portioning steam valve 22 both in the summer and during the winter. This motorized operating mechanism comprises a base plate 35, an upper frame plate 36, and a pair of side plates 31 and 38 respectively. A main actuating rod 39 is located between side plates 31 and' 38 and extends through upper frame plate 35. This main actuating rod is provided with an opening 48 i for the reception of a 'lever 4I which is pivotally secured to a bracket 42 carried by upper frame plate 36. vThe lever 4I is operated by a pin 43 which is secured to thel main actuating rod 39 and passes through an appropriate, opening in lever 4I. A second bracket 44 which is carried by upper` frame plate -36 is provided with an opening 45 which receives lever 4I and acts to guide the same in its vertical movements. A main actuating shaft 41 is journalled in side .plates 31 -and. 38 and has secured thereto a pin.

ion 48 which meshes with teeth 49 formed on the lower portion of main actuating rod 39. Also secured to main operating shaft 41 is a pair of gears 50 and 5I which mesh with a pair of pinions 52 and 53 secured to a shaft 54 journalled inside plates 31 and 38. A pair of ,gears 55 and 5B which are also secured to shaft 54 mesh with a pair of motor pinions 51 and 58. Motor pinion 51 is secured to arotor shaft 59 of a motor which includes a rotor 6I and a iield 'winding 62. In a similar manner, motor pinion 58 is secured to a rotor shaft 63 of a motor 84 which includes a rotor 55 and a field winding 66.

Upon energization offleld winding62, theyrotor El of motor 50 rotates in such direction as to rotate main operating shaft 41 in a counter` clockwise direction as viewed from 'the left in Fig. 1, whereby pinion 48 lowers main actuating `rod 39 and the extended end of lever 4I is moved downwardly. The rotor 85 of motor 54 rotates in the reverse direction when its eld winding 6G is energized with the result that mainoperating shaft 41 rotates in a clockwise direction, whereby pinion 48 raises main actuating rod 39 andthe extended end of lever 4I is moved upwardly..

The limit of upward movement of lever 4I under l the action of motor 64 is determined by a limit switch comprising a stationary contact 51, a pivoted limit switch arm 68, and a cooperating limit switch actuator 69 which is secured to main operating shaft 41. Similarly, the limit of downward movement of lever 4I under the action of motor 60' is determined by a limitl switch vcomprising a stationary contact 10, a pivoted limit switch arm 1I, and a cooperating limit switch actuator 12 carried` by main operating shaft 41. A crank 15 is secured to damper shaft 33 and ls continuously biased for movement in a counterclockwise direction' by means of a spring 10. whereby there is a tendency to move damper 32 to its vertical position wherein it engages a stop 11. The'upper end of a link 10 is pivoted to the outer end of crank 15. The lower end of link 10 is provided withv an elongated slot 10 which receives a pin 00 carried by lever 0|. A bracket 3| which is adjustable upon the lower end of link lil is adjusted to the position shown in the drawing `for summer operation whereby there is no lost motion between pin 00 and link `10 and dampers 3| and 32 are moved in exact accordance with the movements of lever 0 I.

The modulating or proportioning steam valve 22 comprises a casing 02 having the usual partition wall 83 therein which is provided with a valve opening. A valve 00 cooperates with the valve opening and is carried by a stem 05, the upper end of which is pivoted to a link 06. One end of link 86 is pivoted to a bracket 81 carried by casing 32. The link is normally biased to move upwardly by means of spring 00 so as to 'open the valve and allow the iow of steam through the valve 22. 'I'he extended end of link 00 is connected to lever 0| .through means which include 4a spring 89. The lever 0| carries a merone end of resistance 03 being `connected to a` metallic cap 90 and the other end thereof beingconnected to a metallic cap 00. The outdoor controller 9| further includes. a thermostatic element herein shownin the form of a curved bimetallic element 00, having one end secured and* the other end of which carries a movable contact nger 01 that is j adapted to sweep across resistance 03 upon changes in the outdoor temperature. 'I'he outdoor controller 0| may be located outof doors or in'any other position such as to respond to changes ln outdoor gages metallic cap 0l.

temperature, for example, in the outdoor air duct I0, there always being sumcient movement of air .through this duct even .when the damper 3| or 32 is closed to actuate element 00. v The contact finger 01 moves equal distances along resistance 03 ,for equal temperature changes but in the preferred form of the invention, the resistance 03 is wound upon support 02 in a tapered or uneven fashion. When the outdoor temperature is approximately contact nger 01 engages metallic cap 00. When the outdoor temperature is approximately 80, the contact ilnger 01. en- A TheA winding 03 is tapered or wound in such manner that whenthe outdoor temperature is F., the contact tlnger 01 while not'being half way between metallic caps 30 and 05, nevertheless contacts the etl'ectlve center of resistance 03, whereby there is approxi- .mately an equal amount o! resistance between contact ringer 01 and metallic caps 00 and 00. Cap 05 is connected to a resistance 33 which is engaged by a manually adjustable contact 00 connected to an adjustable screw |00 by a wire by'movable contact ringer 01 engages contact screw |00 so as to shunt that portion of resistf ance 00 which was theretofore connected in series with resistance 03.

The mechanism 30 is adapted to be controlled by an indoor controller |03 during the winter. This indoor controller |03 comprises a uniformly wound indoor resistance |00 and a cooperating contact iinger |05whlch is positioned by a curved bimetallic element |06. 'I'he bimetallic element |00 responds to the space or building temperature and may be conveniently located in the return air duct In this particular embodiment of the invention, the contact finger |05 movesfrom one extreme end ofV resistance |00 to the other end thereof upon a predetermined indoor temperature change equal to the permissible change in indoor temperature, say 2 F.

' Ihe outdoor and indoor controllers 0| and |03 I are adapted to control the respective energize.- tions of a pair 'of solenoid coils |01 and i00 which are connected in series, their junction being indicated at |09. Solenoid coils E01 and |00 conjointly position a plunger ||0 which is connected to a ilexible relay switch arm ill by a rod H2.

. Relay switch arm cooperates with relatively stationary contacts ||3 and ||0. The respective energizations of solenoid coils |01 and |00 are also controlled by a balancing resistance lli which is traversed by a. balancing contact linger ||0.that is actuated by main operating shaft 01.

A summer-winter reversing switch generally indicated at illvcor'nprises switch arms ||0 and H0 which are adapted to be simultaneously operated by an insulated handle |20. In the summer position, switch arm |8 engages a contact button |2| and the switch arm ii! engages a l arm |20 engages a contact button |30, switch arm |21 engages a contact button |3|, and switch arm |20,engages a contact button |32'. The mas ter switch |20 however may be operated to an opposite position wherein switchl arm |20 engages a contact button |33, switch arm |21 is entirely disconnected from-the system, and switch armv |20 engages a contact button |30.

A manually operable Ventilating switch for winter operation comprises a swit'ch arm |30 which normally engages a contact |30 but may be operated manually to disengage contact |30 and engage a contact |31. A manually operable switch arm |01 may be utilized for summer ventilation as will hereinafter appear.

A relative humidity responsive control is shown atl |33 and comprises a pivoted switch arm |30 which is operated by a humidity responsive eiement |00, a 'spring 0| normally biasing switch arm |30 out of engagement with a contact |02 against the action of humidity responsive 'element |00 and into engagement with a contact |03. 'I'he humidity responsive element |00 re-` sponds to the relative humidity in the space to be controlled andmay be placed either directly in the space or in the return air duct as shown in the drawing. The humidity responsive element |00 expands ,upon an increase in rela-t Vtive humidity.

An indoor thermostat. comprises a curved bi Y upon changes in indoor temperature.

Power is supplied to the mechanism 34 and associated control devices by the low voltage secondary |50 of a step down transformer I5I, having a high voltage primary |52 which is connected tothe usual line wires. The series connected solenoid coils |01 and |00 are connected across the secondary |50 by means of wires |53,

|54, |55 and |56. A small number of turns of solenoid coil |01 is connected to contact I I4 by a wire I51and a small number of turns of solenoid coil is connected to contact I I3 by a wire |50. Balancing resistance ||5 is connected in parallel with the series connected solenoid coils |01 and |00 through protective resistances |53 and |60 by means of wires |6|, |62, |63 and |64. The junction |00 of solenoid coils |01 and |00, balancing contact linger II6, and switch arm are interconnected by means of wires |65, |65 and |61. The contact 09 isconnected to the right end of balancing resistance |I5 by a wire I1I. 'I'he left end of outdoor resistance 03 is connected to the left hand end of balancing resistance |I5 and to contact button |33 by wires |60, |60 and |10. Contact finger 01 is connected to contact button I2I through switch arm |01 by wires |12 and |62. The left hand end of indoor resistance |04 is connected to the left hand end of the right hand end of balancing resistance ||5` and to contact button |31 through a manually adjustable rheostat |14 by means of wires |13, |15, |16 and |10. Contact iinger |05 is connected to Contact button |36 by a wire |10. Switch arm of winter Ventilating switch is connected to contact button |23 by a wire |00. IIB of summer-winter switch I|1 is connected to contact button |30 of master switch |25 by a wire |0I. The remaining circuit connections and the various control and operating circuits will be pointed out in connection with the summer and winter operations of the system.

Summer operation The parts are shown in their automatic summer operating position. In other words, the master switch |25 has its switchAarms |26, |21 and |20 engaged with contact buttons |30, |3| and |32. The summer-winter switch I|1 has its switch arms IIO and ||0 engaged with contact buttons |2| and |22. Switch arm |35 of ventilating switch is engaged with contact |36. In-

door control resistance |04 and the rheostat |14,

in series, are therefore connected directly in parallel with balancing resistance |I5 and the series connected solenoid coils |01' and |00. Contact finger |05 is disconnected from the control system inasmuch as switch arm ||0 of the summerwinter switch I I1 is not engaged with contact button |23. The indoorcontroller |03 therefore can have no effect on the operation of the system The resistances 93 and 00 of outdoor controller 9|, in series, are also connected directly in parallelwith balancing resistance |I5 and the series connected solenoid coils |01 and |00. Contact ringer 01 is The bimetallic element |44 may be lo- Switch arm' velectrically connected to the junction |00 of solenoid coils |01 and |00 and to balancing contact .finger I|6 since switch |01 is closed, switch arm ment of contact 09 shown in the drawing, and

balancing contact linger I I6 is engaging the center of balancing resistance II5 whereby solenoid coils |01 and |00 are equally energized. Therefore plunger |0 is in a central position wherein relay switch` arm III is midway between con` tacts ||3 and I4. Lever 4| is in its mid-position whereby dampers 3| and 32 are positioned to allow a full flow of outdoor air to the chamber I2 and to the space or building, to be controlled.

.Modulating or proportioning steam valve 22 is closed. In the event district or central steam is being used, the manual shut off valve 21 shouldA be'manually4 closed. -The two-position valve 25 however, is in its open position by a circuit as follows: line |05, switch arm |20A of master, switch |25, contact button |32, wire |06, two-positionl valve 25, and line |01. The two-position' valve 25 is preferably of the type which moves to one of its positions upon energization of a first circuit whereupon said circuit is broken and the valve remains in said position until the completion of a. second circuit whereuponthe valve moves to its other extreme position after which the second circuit is broken. Such valves are well-known in the art. Field windings 62 and 66 of motors 60 and 64 are connected in series across secondary by the following circuit: secondary |50, wire |53, wire |80, limit switch arm 1I, contact Y 10, fieldv winding 62, wire |00, wire I!|0,` field winding 66, contact 61, limit switch arm 50, wire |0| and wire |55 to the other side of secondary |50. Lever 4| therefore remains stationary inasmuch as the two motors and 64 are of equal power and are opposing each other. Electrical blower I3 is continuously energized by the following circuit: line |02, switch arm |21 of master switch |25, contact button |3I, wire |03, wire |04', blower I3 andground |05 to lineISG. The relative humidity is not excessive as indicated by switch arm |30 'being out of engagement with contact |43 ,and the indoor temperature is not excessive since flexible blade |45 is disengaged from contact |46. Mercury switch 00 is in its open position. It might be noted at this time that mercury switch 00 is open when lever 4I is in its upper half portion of movement and is closed when lever 4I is in its lower half portion of movement although other adjustments could used if found desirable. Compressor motor I6 and water valve 30 are both deenergized so that no water is issuing from spray 20 nor is any cooling of the building being effected.

So long as the outside air temperature remains constant, the blower I3 will continuously supply a maximum quantity of fresh outdoor air to the space to be cooled so that'the space will be at a very comfortable temperature of about '15 F. NowY if the outside temperature decreases slightly, contact finger 01 will move along outdoor resistance 93 towards the left hand end thereof and change the effective resistance in circuit with solenoid coils |01 and |00 in such manner that solenoid coilv |00 will become more highly energized than solenoid coil |01 whereupon plunger will move to the right and bring switch arm into engagement with contact ||3. Engagement of switch arm with contact |I3 substantially, short circuits eld winding 62. In other words, the field winding 62 and the small number of turns of solenoid winding |08 are connected in parallel. The energizing circuitl for field winding 66 is now as fol-.

lows: secondary |50, wire |56, wire |9I, limit switch arm 68, contact 61, eld winding 66, wire |90, at which point the circuit branches, one part going by way of wire |89, eld winding 62, Contact 10, limit switch arm 1|, wire |88 and wire |53 whereas the other portion thereof traverses a wire |91, relay switch arm |I|, contactli3, wire |58, the small number of turns of solenoid winding |88 and wire |54 to wire |53 and thereby the other side of secondary |50. Motor 65 therefore is now more highly energized than motor 60 and is able to rotate operating shaft t1 in a clockwise direction as viewed from the lefti in Fig. l whereupon lever 4| begins moving up- Y summer, the amount of outdoor air supplied toresistance wardly and. balancing contact finger IIB moves slowly along balancing resistance i I5 towards the right hand end thereof. This movement of main operating shaft 41 will continue until balancing contact linger ||8 reaches a point on balancing ||5 such that the pull exerted on plunger I0 by solenoid coil |01 equals the pull exerted on plunger ||0 by solenoid winding itilA and the energization of the small number of more nearly to its vertical 4position and the' amount of outdoor air drawn into the space by blower I3 is proportionately decreased. In this manner, as the outdoor temperature continues to drop, the lever 4I will be moved upwardly in small increments until the outdoor temperature reaches 65 at which time the lever lll will have been moved to its upper limit wherein damper 32 engages stop 11 and further outdoor air delivery to the space is discontinued. At this time, limit switch actuator 59 will have engaged limit switch arm 68 to move the saine from engagement with contact 61 whereby held windings t2 and t6 cannot again be energized `while switch arm III is veither in its mid-position or out ci engagement with contact H3.' lin this manner, upon a fall in outdoor temperature during the the space is gradually varied from a maximum to a point where no outside air is supplied thereto inasmuch as the outdoor` temperature is belov;y the desired indoor temperature. c

Whenever the outdoor temperature rises, contact 'finger 91 will move along the outdoor resistance 93 towards the right hand end thereof and thereby change the effective resistance connected in circuit with solenoid coils itl and |08 'in an opposite manner to that previously de-n scribed so that solenoid winding l o1 becomes more highly energized than solenoid winding |03. Plunger I0 therefore moves to the leit and brings relay switch arm into engagement with contact |I4. Ii limit switch arm G8 be out of engagement with contact B1 at this time, eld winding 62 .will be energized as follows: secondary |50, wire |56, wire |55, a small number of turns point the circuit branches, one portion traversing wire |90, field winding 66, contact 61, limit switch arm 68, and wire |9| to wire |56 while the other portion traverses wire |91, relay switch arm III, contact H4, wire |51, a small number ofturns of solenoid coil |01 and wire |55 to wire |56 which connects to the other side of secondary |50. In eitherevent, the current flow through the small number of turns of solenoid winding |01 serves to increase the contact pressure between relay switch arm III and contact ||4 and the motor 60 will be moreI highly energlued than motor 64 so as to be effective to rotate main operating shaft 41 in a counter-clockwire direction as viewedi from the left in Fig. l.l

Such movement of main operating shaft 41 lowers lever 4| and moves balancing contact ringer ||I6 along baancing resistance ||5 towards the left hand end thereof to again equalize the pull exerted on plunger ||0 and move relay switch arm |l| to its mid-position between contacts llt and IM. This downward movement of lever il moves damper 32 away from stop '|11 to increase the flow-of outdoor` air to the space.

Whenever the outside air temperature returns to f approximately '15 the dampers 3| and 32 and lever ll will have been -retrned to the positions shown in Fig. l of the drawing.

lli the outdoor temperature continues to rise, lever' al will move downwardly in small increments from the position shown in Fig. l and initial downward movement from such positioncloses mercury switch 90 and moves damper 3| slightly towards stop 11 to decrease the sup-ply of outdoor airfurnished to the space. The cornpresser motor it is now conditioned .for energiaation whenever the space temperature becomes too high so as to bring ilegible blade into engagement with contact ille. This compressor motor circuit is as follows: line |92, switch aim |21 of master switch |25, Contact button itl, wire |93, wire Ist, wire |99, blade- Mtl, contact Nt, wire 200, mercuryswitch 90,

wire' till, Wire 292, compressor motor, it, wireA tilt, contact button |22, switch arm |69 of summer-winter switch ||1, and ground |95 to line tdt. In this manner, the compressor motor i6 is energized whenever the space temperature becomes excessve if the outdoor temperature is too high. As the outdoor temperature continues to rise, damper 3| is moved more closely to stop 11.

When the outdoor temperature reaches 80 F., movableconta-ct linger 91 will engage metallic cap 95 and the damper 3| will not be quite closed, the amount it is open. depending upon the amount of resistance 98 in series with the outdoor resistance 93. As the outdoor temperature continues to rise, contact nnger lll will sweep across metallic cap 95 whereby this movement of contact ringer 91 is not accompanied by any change in the effective resistance in circuit with the solenoid coils. |01 and |08. But when some maximum outdoor temperature is reached, such 'as 90 F., the contact |02 will engage Contact screw |00 whereby resistance 98 will be short circuited. At .this time, solenoid winding |08 will be substantially short circuited and would be completely short circuited were it not' for the inclusion of protective resistance |00. Relay switch arm will therefore again engage contact ||4 and lever 4| will be lowered until balancing contact nger IIS engages the extreme left end of balancing resistance ||5 at which time solenoid coll |01 will be substantially short circuited and would be short circuited completelyj were it not for protective resistance |50. Solenoid coils |01 and |00 are therefore again equally energized and plunger I |0 returns to its center position. This relatively rapid downward movement of lever 4| brings damper 3|v into engagement with stop 11 so that no outdoor air is now supplied to the space since the outdoor temperature v is so excessive as, to require an undue amount of refrigeration if the space temperature is to be maintained at the desired point.

' If, at any time, the relative humidity should become excessive humidity responsive element |40 will expand suiciently to move switch arm |00 into engagement with contact |43 and comprescenter of balancing resistance Ill. Lever 4| will i sor motor i0 will be energized irrespective of whether or not ,the space temperature is at the desired point and irrespective of the outdoor temperature. This circuit is as follows: line |02, switch arm |21, contact button |31, wire |00, wire |00, wire 204, switch arm |30, contact |43, wire 200, wire 202, compressor motor I0, wire 203, contact button |22, switch arm ||0 and ground |00 to line |00. In this manner, whenever the relative humidity becomes excessive, the space temperature will be lowered below thatdesired, it necessary, soas to'bring the effective temperature to a comfortable value.

Sometimes it may be desired to supplyy a maximum quantity of outdoor fresh air to the space for Ventilating purposes irrespective of the outdoor temperature. In such an event, a full supply of fresh outdoor air may be furnished even though there wo'uld normally be a lesser or zerosupply of outdoor air by reason of the automatic Vcontrol system. This is accomplishedby moving manually operable switch |01 to open circuit position. Such action electrically disconnects contact finger 01 from the junction of solenoid coils |01 and |00. Outdoor resistance 00 and resistance I0, in series, will itherefore be con-l Aing, therefore, of solenoid coils |01 and |00`that can'take place will be due to balancing contact finger ||0 being removed irom the center of balancing resistance lil. It balancing finger |I0 is removed from the center of balancing resistance III, one or the other of solenoid coils |01 and |00 will become more highly energized than its companion coil, whereupon relay switch arm will be moved in the necessary direction to energize the-proper one of motors 00 or 04, whereby to return balancing contact linger |I0 to the mer operation, it will be apparent that normally the amount of outdoor fresh air'supplled to the space is atl a maximum whenthe outdoor temperature is approximately that desired inside the spe and that the supply of outdoor air is decreased as the outdoor temperature Veither vrises above or falls below the temperatunevalue which it is desired to maintain within the space. The summer operation oi' ythe system is also such that when the outdoor temperature has increased above the desired space temperature to such an extent as to only allow a predetermined small f temperature at the desired point Visiutwhenever the outdoortemperature becomes substantially that desired in the space, the cooling means is rendered inoperative except for certain abnormal conditions. However, inthe event the relative humidity within the space becomes excessively effective temperature in the space to a comfortable value. Furthermore, a full supply, of

v outdoor air can be delivered tolthe space under manual control, if desired, irrespective of the outdoor temperature.

Winter operation For winter operation, the reversing switch ||1 is thrown to the position opposite that shown in the drawing so that switch arm i I0 dlsengages contact button |2l and engages contact button |23 and switch arm ||9 disengages contact button |22 and engagescontact button |24. Disengagement of switch arm ||0 from. contact button |2| disconnects movable member 01 from,

and engagement of switch arm ||0 with contact button |20 connects movable member |05 to, balancing contact finger ||0 and the junction |00 of solenoid coils |01 and |00. As a result, outdoor controller 9| is rendered inoperative and indoor controller |00 is placed in command of the mechanism 34. It should be noted that bothy the cold side of indoor resistance |04 and the `oold side of outdoor resistances 00 and 00 in series are connected to the left hand end of balancing resistance ||0 whereby the action of the indoor controller upon mechanism 34 is the same as the action o! outdoor controller 0| thereon.` Movement of switch arm I0 from contact button |22 disconnects compressor motor ||0 from the source oi' vsupply and conditions water valve :for actuation by the humidity control |20 as will hereinafter appear. For winhigh, the cooling means is operated irrespective f of the space temperature in order to bring the ter operation, the manually operable valve 21.

should be opened and the bracket 0| shouldbe moved to the position shown in dotted lines whereby to establish a lost motion connection between link 10 and pin 00 carried by lever 4I. With thelever 4| in its mid-position, as shown in, the drawing, the spring 10 will raise link 10- to take up the lost motion between link 10 and pin 00 whereby damper 32 moves into engagement with stop 11 and the suppiy'oi outdoor air to the space is discontinued.` It will be noted that blower il remainscontlnuously energized.

The rheostat |14 is manually adjusted so that indoor resistance |04 which is just equal thereto. Therefore, with the indoor or space temperature such that movable member |05 engages the extereme right hand en'd of indoor resistance |04, the movable member |05 is contacting the effective center of the combined resistance of resistance |04 and of the rheostat |14. The solenoid coils lill and |08 are therefore equally energized and the balancing contact finger IIB is contacting the center of balancing resistance ||5 with the result that lever 4| is in its midposition wherein damper 32 closes off all outdoor air and the modulating or proportioning steam valve 04 is closed. lt will be noted that further rise in the space temperature can have no effect on the control mechanism 34. In otherwords, when the rheostat |14 is adjusted so as to have a resistance equal to indoor resistance |04, the lever 4| cannot move downwardly beyond the position in which it ls shown in the drawing. However, as the indoor temperature lowers sov that movable member |05 moves along indoor resistance |04 towards the left end thereof, the solenoid coil itil: will become more highly energized than solenoid winding |01 and lever 4| will move upwardly,7 as heretofore explained in connection with the summer operation. Upward movement of lever III is inelective insofar as dampers 3| and 32 are concerned since the pin merely moves upwardly in the slot 19 formed in link 'IB and the damper 32 therefore remains in its closed position. Upward movement of lever 4| however, does allow spring 30 to lift upward movement of lever 4|. As a result, the lever 4| moves trom its mid-position to its exfalls from the desired maximum to the desired minimum value and the modulating steam valve 22 at the vsame time moves from its full closed position to its lull operi position. In' this manner, the steam supply to heating coils 20 is'modulated or proportioned in accordance with changes in the indoor` temperature.

Under ordinary conditions, the room temperature will never 'reach its maximum limit but there are times when this condition may arise, for instance, when there is a rapidly rising outdoor temperature, the room temperature may become excessive or if a ierge group of people should be present in the room there again the temperature may approach the upper permissible limit. It may be desirable under this condition, or for that matter under all conditions, to introduce a smallv supply of. outdoor air so long as the space temperature does not too closely approach its minimum desired iinjt or fall too far below its desired maximum limit. This can be accomplished by changing 'the setting of rheostat |14 so that a smaller amount oi resistance ls in series with indoor resistance itill. When this is done,'movable member |05 must move away from the extreme `right hand end oi. resistance |04 in order to contact the mid-point ol the combined resistance of resistances |0l and 'the rheostat |14. This means :that lever 4| 'will he in its mld-position when contact memher 505 is displaced from the right hand end of resistance-|04 a variable amount depending upon the adjustment of rheostat H4. It

therefore follows that ii' movable-member |05 moves past this eiiective center of these combined resistances and towards the right hand end of resistance |04, the lever 4| will move downwardly somewhat from its mid-position. The maximum 4 there is an amount ofl resistance in series with link 8G an amount which ls proportional to the treme upper position as the indoor temperature downward vmovement of lever 4| when contact finger |05 is in the position shown in the drawing will depend upon the .adjustment of rheostat W4.

During downward movement of leverl from its center position, the tension of spring -59 is lncreasedwhereby modulating or proportionlng steam valve 22 is maintained closed hut 'the pin 80 carried by lever 4| will engage the lower end of slot 19 to move link 18 downwardly whereby damper 32 moves towards the position .shown in the drawing to allow the supplying of a predetermined amount of outdoor air. In the event all of the resistance of rheostat |14 is removed from the circuit, the lever 4|*wil1 move through its lull range, as described for summer operation, upon movement of movable member Iil from one end of indoor resistance |04 to the other end thereof.`

Under these conditions, when the space is cold,

space temperature is intermediate or between its hot and cold limits there will be no and damper 32 will still be closed, and when the space temperature is at its high limit -darnpers e 3| and 32 will assume the position shown in the drawing wherein there is full supply of outdoor air. In this manner, by proper manipulation of rheostat |14, avariable amount oi' outdoor air ranging from zero to maximum supply may he furnished to the space to be heated.

If it should he desired to ventllate the space irrespective of the space temperature, manual switch arm |35 may be moved from engagement with contact |36 and intoengagernent with contact |31. Discngagement of switch arm il@ from contact |36 disconnects movable mercher viii' from the control system and movement switch arm |35 into engagement with contact lill substantially short circuits solenoid coil il as iolvlows: solenoid 003, wire IEZ, protective resistance |50, wire ISI, wire llt, wire llt, contact lill,

3|-32 to the position shown in drawing.

wherein there is a lull supply of outdoor air irrespective of the inside temperature andthe steam valve 22 is closed. It should be understood that this manual switchv |35 is provided 'only in order that the air in the space may be ouiclrly changed if it should loecome desirable to do so.

Whenever the relative humidity ol the air in the space becomes too low, the humidity responsive element Mt will contract and move switch arm istinto engagement with contact iflll so as to energize water valve 3 0 as follows; line iii?, switch arm lill, contact-button lili,

wire. ltd, wire Zilli, switch arm itil, contact liiil.,l

supplied tothe space whenever the space temthere will be a' full supply of steam, when the of whether the system is operating on its summer'v vor winter cycle so that in any eventfno steam can I be supplied tothe heating coils 20. Dlsengage- A .motor I6, and water valve 30.

perature approaches its desired high limit by manual manipulation of rheostat |14. Furthermore, a full supplyof fresh air can be supplied to' the space at any time by manipulation of manual switcharm |35 irrespective of the space temperature. Whenever the relative humidity of the space becomes too low, the water valve 30 is actuated to supply water to the spray 20 whereby to increase the relative humidity in the space and maintain it above some predetermined minimum value.

Operation of th'e master switch If the master `switch |25 be thrown to the position opposite that shown in the drawing, the switch arm |26 thereof will disengage. contact `button |30 and engage contact button |33, switch ar'm |21 will disengage contact button |3|, and switch arm |20 will disengage contact button |32 and engage contact button |34. Engagement of switch arm I3| with contact button |34 establishes a circuit to two-position valve 25 as Y follows: line |05, switch arm |20contact button |34, wire 208, two-position valve 25 to line |01. The two-position steam valve- 25 is` therefore moved to closed position. Itwill be noted that this valve is moved' to closedposition irrespective ment of switch arm |21 from contact button |3| interrupts'all circuits for blower I3, compressor Thisv also takes place irrespectiveof whether the system is operating on a summer or winter cycle so that no air can be circulated whatsoever, there can be no cooling, nor can there be any humidification. Disengagement of switch arm |25 from contact button |30 disconnects switch arm |2| of reversing switch ||1 from the junction ,|00 of solenoid coils |01 and |08 so that neither movable member |05 nor 91 can be connected inthe control system for mechanism 34. Engagement of switch arm |20 with'contact button |33 substantially short circuits solenoid coil |01 as follows: solenoid coil |01, wire |64, protective resistance |53, wire |03, wire |59, wire |10, contact button |33, switch arm'l26, wire |01, and wire |05 to the-junction |03.' Solenoid coil |03 therefore becomes more highly energized than 'solenoid coil |01 and plunger ||0 moves to the right to bring switch arm`| into engagement with contact ||3. Lever 4| is therefore moved upwardly to its extreme position by means of motor 04 as heretofore explained and this upward movement will be limited by opening of limit switch 01-08. Irrespective of whether the system be operatingr on the summer cycle or the winter cycle, damper 32 will assume its vertical position wherein it engages stop 11 and the outdoor air inlet will be completely closed off. Modulating steam valve 22 will move to its full open Iposition but this can have no effect inasmuch as two-position steam valve 25 has been moved to closed position.

From the foregoing description of. the complete system, it'will be seen that the present in'- vention provides an allyear around temperature control system by which a space or building may be maintained within denitetemperature limits during the winter and the temperature thereof maintained below some predetermined maximum during the summer. It will be noted that the t change-over from the summer cycle to the winter cycle is simply accomplished by a minimum number of manual operations all of which are extremely simple.V It will further be seen that the manipulation of a single master switch renders the system completely inoperative irrespective of whether it be onthe summer or winter cycle. In addition, both the summer cooling and the winter' heating portions of the complete system contain many points of novelty in themselves as has heretofore been explained in detail in connection with 'the operation of each of these portions of the system. n

It will be appreciated that many changes can be made in the entire system or in either its summer or winter operating characteristics by I thdse skilled in the art without vdeparting from toa space which it is desired to control,` meansV for controlling said damper means to move the samethroughone range in the winter, means for ,controlling said dampermeans tomove the same n through a different rangein the summer, and` a single manually operable master control for rendering the entire system inoperative and for 4 operating said damper means to move the same to closed position to prevent the flow of outdoor air Vto said space irrespective of whether the damper means was being controlled for summer or winter operation.

2. A system of the class described, comprising, in combination, a combined heating and cooling chamber, circulating means for continuouslyy causing a flow of air therethrough and into a' space the temperature of which it is desired to control, damper means in control of the iiow of air to said chamber from theoutside atmosphere, heating and cooling means'associated with said chamber' and effective to change the temperature of the air passing therethrough, means for operating said damper means in one cycle and for controlling said cooling means in the summer, means for actuating said damper means in another cycle and for controlling said heating means'in the winter, and a single manually operable master control associated with the damper means, heating means, cooling means, and circulating means for rendering the heating means, cooling means and circulating means inoperative and for operating said damper means to interrupt communication between said chamber and the outside atmosphere irrespective of whether the damper means is operating on a cooling or lheating cycle.

3. A cooling system of the class described, comprising, in combination, means for circulating outdoor air to a space the temperature of which it is desired to control, damper means for controlling the volume of outdoor air supplied to said space,

thermostatic means influenced by outdoor air temperature, and connections betweenv said ther-Y mostatic means andsaid damper means by which the" thermostatic- Vmeans positions the damper means to allow'a maximum supply of outdoor air when thetemperature thereof is at one value and to decrease the supply of `outdoor air as the temperature thereof rises or falls to other predetermined values above and below said first-mentioned temperature value.

4.. Acooling system of the class described, comprising, in combination, means for circulating out-door air to a space the temperature of which -it is desired to controL damper means for controlling the volume of outdoor air supplied to mid space, ,thermostatic means iniiuenced by outdoor .air temperature, and connections between said air temperature, and connections between saidV thermostatic means and said damper means by which the 'thermostatic means positions the damper means to allow a maximum supply of oui'- door airv when the temperature thereof is at one value and to decrease the supply oi outdoor air as the temperature thereof rises or ialls to other predetermined values above and below said nrstmentioned temperature value, cooling means, a thermostat responsive to the temperature of the space in control of said cooling means and means associated With said thermostatic means to pre-` vent control of the cooling means by the space temperature responsive thermostat when the outdoor air `temperature reaches a predetermined low value. l

6. y A cooling systemof the class descri'oed, comprising, in combination, meansor circulating outdoor air to a space the temperatine of "which it is desired to control, damper means for centrolling the volume of outdoor air supplied to said space, thermostatic means influenced by outdoor air temperature, Aconnections between said the-rdoor air supplied to said space, moto ,v mostatic means and said damper means by which the thermostatic means positions the damper means to allow a maximum supply ci outdoor air when the temperature thereof is at one vaille to decrease the supply of outdoor air as temperat-ure thereof rises or falls to other predeterminedl values above and oelow said first-,mentioned temperaturevalue, cooling means, a thermostat responsive to the temperature oi the space for operating said cooling means to maintain the space temperature below a predetermined mar-:imum, and a humidity responsive element responsive to the relative humidity of said space for additionally controlling said cooling means in a. manner to place said cooling means in operation for dehumidifying the 'space when the space relative humidity becomes excessive.

'7. A cooling system of the class described, comprising, in combination, circulating means icr circulating outdoor air to a space, dampermeans movable from one extreme position to another extreme position for varyingtlie vol-"f c c outcontrol of said damper means, t means influenced by outdoor i controlling said motor means to move the e i'npeiGA means between said extreme manually operable device associated motor for operating the damn-er means te permit a. predetermined maximum flow ci outdoor cir or to discontinue all flow ci outdoor air to said space irrespective of the value ci the outdoor air ternperature. I

8. A control system comprising, in consomation,

v1 gli means for circulating outdoor air to a space, damper means in control of the volume. of outdoor air supplied to said sparse,` said damper means being arranged to vary the iiow of outdoor air to said space from a minimum to a maximum and then to a minimum upon continuous movement of the damper meansinone direction from a first position to a second position, electrical means. associated with said demper means for moving the same, and an outdoor temperature influenced thermostat'in control of said eiectrlralmeans to control the electrical means to cause movement of said damper means from said first position to said second position upon change in said outdoor temperature in only one direction.

il. in combination, circulating means for circulating air to a'. space to he heated. damper means for permitting outdoor air he supplied to said space, heating means .heating the air supplied to said space. an electrically operable device including a movable clement, connections between said element. heating means and damper .means for gradually decreasing the heat supplied hy said heating means While maintaining said damper means in position to prevent circulation of outdoor air to said space until the heating means has been rendered inoperative and thereafter maintaining said heating means inoperative and operating the damper means to gradually permit the supplying of an increasing amount of outdoor air to said space during continuous movement of said element 'in a single direction through a'predetermined range', a thermostat connected to said device for operating the same tomove said element through said range upon a predetermined temperature Variation, and means associated with said .thermostat and device for reducing the range oimcvement of said element v upon said predetermined temperature Variation.

door temperature, connections between said' ther- .mostatic means and said motor means by which the thermostatic means positions the damper` means to allow a maximum supply of outdoor air to ilow to said space when the outdoor temperature is at a given value and to decrease the supply Vin? outdoor air upon rise or fall of the outdoor temperature above or below said value, cooling means to cool the space, means responsive to the temperature ci the space for controlling said cooling means in a manner to place said cooling means in operation when tlie'space temperature rises to a predetermined value, and means inl Aiiuenced by space relative humidity for placing said cooling means in operation when space relative humidity rises above a predetermined value,

il. i cooling system of the class described. eemnrisiug, in combination, damper means in conti ol ci thence-iv of outdoor air to c, space to be contre ed, motor means in control cil said damper tliermostatic means iniduenced by outdoor temperature, connections said thermostatic means and said motor menos by which the thermostaticmeans the demper means to sillonv s. maximum supplyA ci outdoor air to flow 'coseid space when the outdoor temperature is at' a given value and to decresse the supply of outdoor air upon rise or tall in the outdoor temperature shove or below said value, cooling means to cool the space, a mace temperature responsive control normally in control of said enclins;l means lill path of travel, motor means in control of saidv movable member, an outdoor temperature influenced thermostat in Ycontrol of said motor means which controls the motor means in accordance with the outdoor temperature, damper means in control of the flow of fresh air to a space to be conditioned, connections between said movable member'and damper means, electrically controlled cooling means, a controller in control thereof, and a switch operated by said movable member when in a predetermined position tov prevent operationl of said cooling means bysaid controller. Y

13. A system of the class described, comprising,

in combination, damper means in control of the t ow of fresh air to a space, a movable member in control of said damper means and operative to move the damper means from a position permitting a maximum flow ,of fresh air to the space to a position in which no ow of fresh air to said space is permitted, electric motor means in control of said movable member and operative to move the same throughout its complete range, variable resistance means in control of said motor means operative to position the motor means according to the condition of said variable resistance means, means inuenced by outdoor temperature to gradually vary said variable resistance means fromv its extreme condition which represents a full flow of fresh air throughout the maximum portion of its possible variation, and a switch operated at a definite temperature in control of the Iremaining possible variation of said variable resistance means.

14. In a damper control for an air conditioning system, in combination, damper means in control of the ilow of outdoor air to a space to be controlled, a movable member, connections between the movable member and damper means by which continuous movement of the movable member throughout a predetermined range moves said damper means from a position in which no outdoor air is permitted to ow to said space, to a position in which a maximum flow of outdoor air to said space is permitted and then to a position in which no flow of outdoor air is permitted to said space, reversible motor means in control of said movable member, switching means in control of said reversible motor means, a pairof oppositely acting electrical devices in control of said switching means, a variable resistance controller responsive to temperature conditions associated with saidy oppositely acting electrical'means and operative to vary the respective energizations thereof whereby to operate said switching means, and a variable resistance device operated by said motor means associated with said oppositely acting electrical devices operative to reestablish their normal respective energizations when the reversible motor means has positioned the movablemember in accordance with the temperature to which said controller responds. l

15. In a damper' control for an air conditioning system, in combination, damper means in control of the ow of outdoor air to a space to be controlled, a movable member, connections between the movable member and damper means by which continuous movement of the movable member throughout a predetermined range moves said damper means from a position in which no outdoor air is permitted to flow to said space, to a position in which a maximum ow of outdoor air to said space is permitted and then to a position in which no flow of oudoor air is permitted to said space, reversible motor means in control of said movable member, switching means in control of said reversible motor means, a pair oi' oppositely acting electrical devices in control of said switching means, a variable resistance controller responsive to temperature conditions associated 4with said oppositely acting electrical means vand operative to vary the respective energizations thereof whereby to operate said switching means; a lvariable resistance device operated by said motor means associated with said oppositely acting electrical devices operative to reestablish their normal respective energizations when the reversible motor means has positioned the movable member in accordance with the temperature to which said controller responds, an external resistance in series with said variable resistance controller whereby the movable member cannot be moved to one of its extreme positions, and a switch to short-circuit said external resistance.

16. In a control system, in combination. a movable member movable throughout a given range, a device to be controlled thereby, motor means in control of said movable member, a rst controller associated with said motor means operative to cause the same to move the movable member throughout its complete range of movement, a second controller associated with said motor means operative to cause the same to move the movable member through only a portion of its complete range of movement, and means to selectively place one or the other of said controllers in control of said motor means.

17. In a control system, in combination, a movable -member movable throughout a given range, a device to be controlled thereby', electric motor means connected to said movable memberand operable to move the same `throughout its complete range of movement, a first variable resistance controller for operating said motor means to move said movable member through its complete range of movement, a second variable resistance controller for operating said motor means to move said movable member through only a portion of its complete range of movement, and switching means selectively operable to place one or the other of said variable resistance controllers in control of said motor means.

18. In a control system, in combination, a movable member movable throughout a given range, a device to be controlled thereby, reversible motor means connected to said movable member oppositely operable to cause reverse rotations of.`

'and operative to move the same throughout its said motor means, a pair of oppositely actingy electrical devices in control of said switching means and operable to move said switching means to a position in which said motor means is stopped when said devices are substantially equal,- ly energized, current varying means operated by the reversible motor means and associated with said electrical devices to maintain their energlzations substantially equal at all times, a first conoutdoor air to said space when the upon change of said condition to values either above or below an optimum value, second means.

responsive to an air condition to move said damper means towards open position upon change in said last-named condition in only one direction, means to selectively place said first or second means in control of said damper means, and means to place said damper means in full open position irrespective of the value of the conditions to which said rst and second means' respond.

27. In a heating and cooling system fora space, in combination, means to heat the space, means to cool the space, means in'control of the supplying of fresh air to said space, space temperature responsive means in control of saidfresh air supplying means and heating means operative to control the heating means to mainair to the space if said condition increases above' or decreases below an optimum value, and means to selectively place said first-mentioned space temperature responsive means in control of said heating means and fresh air supplying means or said outdoor condition responsive means and Ysecond-mentionedv space temperature responsive means in control of said fresh air supplying means and said cooling means.

28. A temperature control system of the class described, comprising, in combination, a -temperature changer for changing the temperature of a space to be controlled, means to deliver outdoor'air to said space, damper means in control of the ilow of outdoor air to said space, means including an outdoor temperature thermostat to position said damper means to reduce the ow of4 outdoor air to said space when the outdoor temperature either rises to a high value or falls to a low value, and means responsive to space temperature controlling said temperature changer to maintain the space temperature at a value between said -high and low outdoor temperature values.

29. A cooling system of the classdescribed, comprising, in combination, a cooling device for lowering the temperature of a space to be controlled, means to' deliver outdoor airk to said space, damper meansin control of the flow of outdoor air to said space, means including an outdoor temperature influenced thermostat to position said damper means to reduce the flow of outdoor temperature either rises to a highvalue or falls to a low value, and means responsive to space temperature controlling said cooling device to maintain the space temperature at or below a value between said high and low outdoor temperature values.

30. A temperature-changing system of the class described, comprising, in combination, a temperature changer to change the temperature of a space, means to deliver outdoor air to said space, damper means in control of the flow of outdoor air to the space, motor means in control of said damper means, an outdoor temperature influenced thermostat in control of said motor means to variably position the same, a space temperature responsive thermostat in control of teminuenced perature changer, andrneans operated by said motor means to permit control of the temperature motor means in control of said damper means,

an outdoor temperature influenced thermostat in control of said motor means to variably position the same, a space temperature responsive thermostat in control `of said cooling device, means operated by saidV motor means to permit control of the cooling device by the space temperature responsive thermostat only during a portion of the range of movement of the motor means, and 4means responsive to the relative humidity of the space to operate the cooling device upon high space relative humidity irrespective of the position of said motor means.

32. In a heating and cooling air 4conditioning system,l in combination, means for cooling "al space, means for heating said space, means for supplying fresh air to said space, temperatureu responsive means for controlling said heating and coolingmeans, said temperature responsive means being arranged for controlling said heating means in a manner to increase the supply of heat upon increase of heat demand during the heating cycle of the system, and to increase the operation of the cooling means upon increase in demand for cooling during the cooling cycle, thermostatic means responsive to outside temperature, thermostatic means responsive to space temperature, and means for placing said space thermostatic means in control of said fresh air supplying means during the heating cycle, and for placing said outside thermostatic means in control of said fresh air supplying means during the cooling cycle. l

33.'In an air conditioning system, in combination, a conditioning chamber through which air is adapted to be passed, means for causing a flow of air through saidvconditioning chamber and to a space to be conditioned, means for withdrawing air from said space and for passing it to said conditioning chamberyfresh air supply means for said conditioning chamber, a fresh air iiow controller incontrol of the flow of fresh air into said conditioning chamber, reversible electric motor means for positioning said controller,

thermostatic means influenced by outside temperature, and circuit connections controlled thereby in control of -said electric motor means and operative to energize said electric motor means in a manner to operate said air flow controller to a position for reducing the supply of yfresh air to said conditioning chamber when theV temperature of said thermostatic ,means rises above or falls below predetermined values.

34, In an air conditioning system, in combination, a conditioning chamber, duct means for connecting said conditioning chamber with a space to be conditioned, means for supplying fresh air to said space, means for controllingl the fresh air supply, thermostatic means for controlling said fresh air supply controlling means, said thermostatic means and said fresh air supply controlling means being` arranged to cause the supply of fresh air to be increased upon temperature fall at said thermostatic means and to be decreased upon temperature rise at said thermotion, a conditioning chamber, duct means for connecting said conditioning chamber with ay space to be conditioned, condition changing means in said chamber for changing the condition of the air in said space, condition responsive means influenced by the condition of the air in said space for controlling said condition changer for maintaining desired space conditions, means for supplying fresh air to said space, means forvcontrolling the fresh air supply, thermostatic means for controlling the fresh air supply controlling means, said thermostatic means and said fresh air supply controlling means being arranged to cause Y a maximum amount of fresh air to be supplied when the fresh` air temperature is such that it aids in maintaining desired conditions within the 'honingA chcmbe means for supplyingfresh air to said space, a

s'pace and to decrease the fresh air supply when the fresh air temperature deviates from such value, and means for preventing operation of said condition changer when a predetermined volume of fresh air is being supplied to said space.

36. In an air conditioning system,'in combination, a conditioning chamber, duct means for connecting said conditioning chamber witha space to be conditioned, means for supplying fresh air to said space, thermostatic means for controlling said fresh air supply controlling means, said thermostatic means and said fresh air supply controlling means being arranged to cause a maxi- 'mum amount bf fresh -air to be supplied when the fresh air temperature is such that it aids in maintaining desired conditions within theA space and to decrease the fresh air supply when the fresh air temperature deviates from such value, means for heating the space, means for cooling the space, means for controlling said heating means and said cooling means, means for restricting the fresh air supply when the heating means is in operation, and means for preventing operation ofthe cooling means when a predetermined amount of fresh air is being supplied to said space.

37. In an air conditioning system, in combination, a conditioning chamber, means including a fan for causing air to flow through saidy condir to a space being conditioned,

damper for controlling the fresh air supply, electricmotor means for actuating said damper, condition responsive means influenced by outsidel temperature for controlling said electric motor means in a manner to cause the position of the damper tobe shifted towards closed positionrupon rise or fall in outside temperature above or below a predetermined value, 'a controller for controlling the operation of said fan, and means con'- trolled by said fan controller for causing said electric motor means to run to a position in which the damper is substantially closed whenever said fan is placed out of operation. y

38; In an air. conditioning system, in combination, a conditioning chamber, means including a fan for causing air to flow through said condi- A tioning chamber to a space being conditioned, means for supplying fresh air to said space, a damper for controlling the fresh air supply,elec tric motor means for actuating said damper, said electric motor means having a control circuit, a

damper position controller connected into said control circuit forgraduatingly controlling said damper motor means in a manner to provide a plurality of damper positions, a fan controller for controlling. the operation of said fan, and means controlled by said fan controller connected into said control circuit with said damper position controller for causing said electric motor lmeans for supplying fresh air to said space, a

damper for controlling the fresh air supply, electric motor means for actuating said damper, a."

controller for controlling the operation of said fan, and means controlled by said fan controller for causing said electric motor means normally to Y run said damper from a substantially closed position to at least a predetermined minimum open position when the fan is placed into operation, and for causing said electricimotor means to run to a position in which the damper is substantially closed whenever said fan is placed out of opera-` tion.

40. In an air conditioning system, in combination, means includingY a fan for supplying fresh air to a space .to beconditioned, a d amper for controlling the supply of fresh air, electric motor means for operating said damper, condition responsive means for controlling said damper motor means to cause the supply of fresh air to be varied in accordance with changes in value of the condition to which said condition responsive means responds, means for normally preventing j said condition responsive means from operating said electric motor means to a position' in which said damper is closed for thereby normally maintaining at least a minimum fresh air supply, a controller for controlling the operation of said fan, and means controlled by said fan controller for causing saidelectric motor lmeans to r'un to a position in which the damper is Substantially closed whenever the fan is placed out of operation. l

4l. In an air conditioning system, in combination, meansincluding a fan for supplying fresh air to a. space to be conditioned, adamper for controlling the supply of fresh air, damper motor means for actuating said damper, condition responsive means for controlling said damper= motor means to cause the supply-of fresh air to be varied in accordance with changes in value of the condition to which said condition responsive system, in combination, means for cooling a space, l

means for heating said space, means for supplying fresh air to4 said space, means for controlling said heating and cooling means, said controlling means being arranged for controlling said heatv7g;

ing means in a manner to increase the supply of heat upon increase in heat demand during the heating cycle,'and to increase the operation of the cooling means upon increase in demand for cooling during the cooling cycle, a damper for controlling the supply of fresh air, electric motor means for actuating said damper, an outdamper means associated with said circulating side temperature responsive thermostat, a thermostaticY means influenced by space temperature, and electrical connections between said outside temperature responsive thermostat, said 'space temperature influenced thermostatic means, and said electric motor means, for placing said outside temperature responsive thermostat in control of said electric motor means during the cooling cycle, and for placing said inside increase the supply of heat upon increase in heat demand during the heating cycle of the system, and to increase the operation of the cooling means upon increase in demand for cooling during the l, cooling cycle, thermostatic means influenced by inside and outside temperature for controlling said fresh air supplyingmeans, and means for substantially restricting the fresh air supply when 'said heatingk means is placed into A operation.

44. In a cooling system of the class described,

in combination, circulating means for circulating outdoor air to a space the temperature of which it is desired to control, means to cool the space,

means for varying the volume of theoutdoor air supplied to said space, outside temperature ylnuenced thermostatic means for controlling said damper means, saidthermostatic means including a controller associated with said damper means in a manner to provide a maximum supply of, outdoor air when outside temperature is at one value and to reduceY the outdoor air supply when outside temperature rises to a higher value, means for preventing said controller from completely closing said damper when the outside temperature is below a value which does not place an excessive load upon the system, to thereby provide a minimum fresh air supply, and means. for placing said last mentioned means out of operation when the outdoor temperature becomes l excessive.

45. In an air conditioning system, in combination, a conditioning chamber, means for causing a flow of air through said conditioning chamber to a space to be conditioned, means for supplyingfresh air -to said space, a damper for controlling the flow of fresh air, means for positioning said damper for varying the supply of fresh air to said spaceA in accordance with the condition of the fresh air available, a cooling coil in said conditioning chamber arranged to be directly contacted by the air flowing through said chamber, power actuated means connected to said'cooling coil for supplying liquid refrigerant to said cooling coil and for withdrawing evaporated refrigerant from said cooling coil, means including a space temperature responsive thermostat for placing saidpower actuated means into operation ywhen the space temperature becomes excessive; to thereby reduce the space temperature, and means including a humidity vresponsive device for placing said power actuated means into operation independently of the temperature responsive means whenever the space relative humidity becomes excessive.

46.` In a system of the class described, in combination, means including a fan for supplying fresh air to a space to be conditioned, a damper for controlling the supply of fresh air, damper control means including damper motor means and condition responsive means for controlling said damper motor means to cause the supply of fresh airto be varied in accordance with changesin value of the condition to which said condition responsive means responds, said damper control means including minimum position means for normally preventing said condition responsive means from operating said motor means to a posi tion in which the damper is closed for thereby maintaining at Vleast a minimum supply of fresh air during normal operation of the system, said damper control means also including means controlled by said condition responsive means for overcoming said 'minimum position means when said condition varies to a predetermined value, and means controlled'by said fan controller for operating said motor means in a manner to cause substantially complete closing-of said fresh air damper when said fan is placed out of operation.

47. In a system lof the class described, in combination, an air conditioning unit for conditioning the air for a space, said unit including fresh and return air supplyopenings and a fan for forcing circulation of such fresh and return air through said unit, damper mechanism for controlling the supply of fresh air for thereby varying the proportions 4of the fresh and return air supplied to said unit, control means for positioning said damper mechanism including a thermostatic device and a motor device controlled thereby, said thermostatic device responding to a temperature influencing the temperature of the mixture of fresh and return air and acting graduatingly to cause movement of said damper mechanism from a positionwherein the flow of fresh air is at a maximum in a direction for reducing the ow of fresh air -as the temperature at said thermostatic device varies from a predetermined value in a predetermined direction, one of said devices including means for interrupting the graduating control of said damper mechanism by said thermostatic device when the fiow'of fresh air is reduced to a .predetermined minimum to thereby maintain at least a minimum flow of fresh air even though the temperature at said thermostatic device .continues to vary in said predetermined direction, a controller for -controlling the operation of said fan, and means controlled by said fan controller for operating said motor device in a manner to cause substantiallycom plete checking of the flow of fresh air when said fan is placed out of operation.

i 48. In a system of the class described, in combination, an air conditioning unit for conditioning the air for a space, said unit includingv fresh and return air supply openings and a fan for forcing circulation of such fresh and return air through said unit, damper mechanism for controlling the supply of fresh air for thereby varying the proportions of the fresh and return air supplied to said unit, control means for positioning said damper mechanism including a thermostatic'device and amotor device controlled mil thereby, said thermostatlcdevice responding to a temperature influencing the temperature of the mixture of fresh and return air and acting graduatingly to cause movement oi! said damper mechanism from a position wherein the ow ot fresh air is at a maximum in a direction for reducing the iiow of fresh air as the temperature at said thermostatic device varies from a predetermined value in a predetermined direction, minimum position means associated with one of said devices vfor interrupting the graduating control of said damper mechanism by said thermostatic device when the flow of fresh air is reduced to a predetermined minimum to thereby maintain at least a minimum ilow of fresh airI even though the temperature at said thermostatlc device continuesh to vary in said predetermined direction, said minimum position means being arranged to be overcome by said thermostatic device when the temperature at said thermostatic device varies in said predetermined direction to a predetermined value to thereby reduce the flow of fresh air below said minimum value,v a controller for controlling the operation of said ian, and means controlled by said Ian controller for operating said motor device in a manner to cause substantially complete checking of the ow of fresh air when said Ian is placed out of operation.

GEORGE D. KINGSLAND.

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