USRE21166E

USRE21166E - Method and apparatus for automat

Info

Publication number: USRE21166E
Authority: US
Publication date: 1939-08-01

Description

A. E. SEALS Re. 21,166 LING TIONING SYSTEMS Aug. 1, 1939.

METHOD AND APPARATUS FOR AUTOMATICALLY CONTROL I 14, 1931 6 Sheets-Sheet 1 THE OPERATION OF AIR COND Original Filed Sepi.

Aug. 1, 1939.

METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING A. E BEALS THE OPERATION OF AIR CONDITIONING SYSTEMS Original Filed Sept. 14, 1951 6 Sheets-Sheet 2 Iii-.1. lli

ll 7" i Aug. 1, 1939. E BEALS Re. 21,166

METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE OPERATION OF AIR CONDITIUNING SYSTEMS 7 14, 1931 6 Sheens-$heet 5 Original Filed Sept In vlsnron:

J a a A. I

Jun M W b I H a /5 l 7 6 i H Aug. 1, 1939. A. E, BEALS 21,166

METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE OPERATION OF AIR CONDITIONING SYSTEMS Original Filed Sept. 14, 1931 6 SheeLb-Sheet 5 gay/ m r Aug. 1, 1939. E BEALS Re. 21,166-

METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE OPERATION OF AIR CONDITIONING SYSTEMS Original Filed Sepi. 14, 1931 6 Sheets-Sheet 6 MTNE-SJ" I I .8Y 9- MW I rrme gr:

Reissued Aug. 1, 1939 UNITED STATES PATENT OFFICE Albert E. Beals, Norwich, N. ,Y.

Original No. 1,986,316,

Serial No. 562,817, September 14, 1931.

dated January 1, 1935,

Application for reissue December 24, 1936, Serial No.

34 Claims.

This invention relates to a new and improved method and apparatus for automatically controlling the operation of air conditioning systems and in which is utilized a new and novel thermonecessary, especially during the summer months, i

15 to not only maintain the temperature of the air of such inclosures within certain limits depending upon the atmospheric conditions of the outside air, but that the relative humidity of the inside air be controlled in relation to the temperature of the outside air, and also in relation to the percentage of moisture contained in the outside air.

Likewise, it has been found very difficult, if not impossible, to manually control the various units of an air conditioning system for inclosures to properly maintain the desired effective temperatures of the inside air due to the practically continuous changes which occur in the temperature and relative humidity of the outside air, and also to the variations in temperature and relago tive humidity of the inside air due to the extremely variable load brought about by the constantly varying number of persons in the inclosure.

An object of this invention is to provide a a thermostatic unit responsive to temperature changes through a comparatively wide range (as, for instance, from sixty degrees to one hundred degrees Fahrenheit), and'where the registering member of the unit moves through equal incre- 40 ments of space in response to equal increments of temperature variation.

A second object is to provide a thermostatic unit whereby the registering member shall assume a certain definite location for a certain deflnite temperature.

A third object is to provide a thermostatic unit which will have a maximum degree of flexibility and an abundant extended range of movement "of so the actuating member. In accomplishing this result, I utilize the evaporative pressure of a volatile fluidas the operating agent while the actuating member of the thermal couple is constructed to e'xpandand contract through the agency of vary- 5 ing increments i pressure due to uniform mo ments of temperature to which the thermosensltive member of the couple is subjected.

A further object of this invention is to provide an apparatus for controlling the operation of an air conditioning system which will be afiected by the varying conditions of both the inside and the outside air for automatically maintaining. the condition of the air in the inclosure at a predetermined relation to the variable condition of the outside air so as to produce the maximum degree of comfort for the people in the inclosure.

Another object is to obtain the maximum degree of economy in the operation of an air conditioning system by reducing to a minimum the unnecessary loss of refrigeration by automatically regulating and varying the effective temperature of the inside air in accord with the effective temperature of the outside air, and at the same time, holding the relative humidity within desired limits.

By effective temperature is meant that empirical scale of temperature sensation experimentally determined and plotted which indicates the relations between the actual dry bulb and wet bulb temperatures producing the same sensation of temperature to the human body.

An efiective temperature chart compiled from tests conducted at the American Association of Heating and Ventilating Engineers, research laboratory, is well-known in the art and needs no further amplification here.

Still another obiect'is to provide a control apparatus for air conditioning systems which is applicable to be utilized with various conventional systems now in use.

A further object is to provide a control apparatus which is simple, economical and durable in construction, positive and accurate in operation, and which will require the minimum amount of attention.

Other objects and advantages pertaining to the details of the structure and the form and relation of the parts thereof, will more fully appear in the following description, taken in connection with the accompanying drawings in which:

Figure 1 is a top plan of a temperature and humidity actuated control instrument embodying the various features of this invention.

Figure 2 is an enlarged longitudinal vertical sectional view through one of the slide members, and the thermostatic control unit therefor, taken substantially in the plane of the line 2-2, Figure 1.

Figure 3 is an enlarged detail plan view of adjacent ends of electrical contact blocks with one of the blocks shown in section.

Figure 4 is an enlarged transverse vertical sectional view taken in the plane of the line 4-4, Figure 1.

Figure 5 is a detail vertical sectional view taken substantially in the plane of the line '5-5, Figure 2.

Figure 6 is a detail vertical section taken on line 66, Figure 2.

Figure '7 is an enlarged transverse vertical sectional view taken on line 'I-'I, Figure 1.

Figure 8 is a detail section on line 8-8, Figure 2.

Figure 9 is a detail transverse section taken on line 9-9, Figure 1.

Figure 10 is diagrammatic view illustrating the manner in which my novel control apparatus may be operably connected with an air conditioning and circulating system.

Figure 11 is a chart by which, when the outside effective temperature is given, the required inside atmospheric condition may readily be determined for producing the maximum degree of comfort, and is based upon maintaining the relative humidities at 55% throughout the range. The dry bulb and wet bulb temperatures for any particular outside effective temperature, also hear such a relation to each other that the inside effective temperature will be midway between the outside eifective temperature and an efiective temperature of sixty-six degrees.

The apparatus, as illustrated in the drawings, consists of a substantially flat supporting frame or table I mounted over a pair of platforms 2 arranged beneath respective end portions of the table I, and to which the table I is secured in vertical spaced relation by means of tie rods 3. There are six of these tie rods 3 for each platform 2, and they have their upper ends screwthreaded in the lower portion of the table], and have their lower ends reduced in diameter and clamped to respective platforms 2 by means of nuts 4, as shown moreparticularly in Figures 4 and 7.

The table I has provided in the upper surface thereof, a plurality of, in this instance five, longitudinally extending

guide ways

5, 6, I, 8 and 9 upon which are mounted for longitudinal reciprocative movement, slide members III, II, I2, I3 and I4. Four of these slide members, III, II, I2, and I3 are arranged in two pairs mounted in longitudinal spaced relation upon the

respective guide ways

5, 6, I and 3, and each pair of slides is adapted to operate in a direction at an angle to the other while the slides of each pair are mounted to operate in parallel spaced relation and independently of each other.

The remaining slide I4 is, as shown in Figure 1, mounted substantially midway between the slides III and II, and is adapted for longitudinal reciprocative movement in parallelism with the movement of said slides.

It is very essential in a device of this character that each moving part be operated with a minimum amountof friction, and for this purpose, each of the slides III, II, I2, I3 and I4 is mounted upon balls l5 composed of steel or other suitable material and positioned between the slides and the respective guide ways in corresponding aligned grooves I6 and I1 formed in opposite adjacent sides respectively of the slides and guides. (See Fig. 4).

Each of the slides III, II, I2 and I3 is actuated by a respective dry or wet bulb thermostatic unit I8, I9, and 2I in a manner hereinafter more fully described, while the slide I4 is connected with and actuated by the slides I2 and I3 through the medium of a bar 22 arranged to extend transversely over the table I and which is .pivotally connected intermediate its ends to the slide I4 by means of a ball bearing member 23 arranged in a suitable socket or recess 24 provided in the under side of the bar 22, said bearing member being pivotally maintained in its operative position by means of a pivotal shouldered screw 25 which extends downwardly through registering openings in the bar 22, and

bearing member 23, and is screw-threaded in the forward end of the slide l4.

The bar 22 is provided with a longitudinal channel or groove 26 in the lower surface of the ends thereof and is slidably connected with the slides I2 and I3 at respective sides of the pivot 23 by means of ball bearing members 21 positioned in the channel 26 at respective ends of the bar 22, and which are secured by shouldered screws 28 to the corresponding slide members I2 or I3 at the inner ends thereof. (See Figures 1, 7 and 9).

The bearing members 21 each have a free sliding fit in the channel 26 so as to freely permit any longitudinal movement of the bearing members along the bar 22 which may be necessaryduring the longitudinal movements of the respective slides I2 and I3, and to also freely permit any longitudinal movement of the bar 22 relative to the slides I2 and I3 during the longitudinal movements of the slide member I4, as will be hereinafter more apparent.

The slides III, II, I2, I3 and I4 may, as shown in Figure 1, be each provided with a suitable scale as a, b, c, d, and e respectively. These scales may be provided at one side of the slides upon the surface of the table I, the graduations of each of these scales being spaced according to the oifice of the respective slide member, and each slide member may be provided with an index 29 which is secured to or made integral therewith for assisting in determining the accuracy of the instrument, as will hereinafter be more apparent.

The slide members III and II are each provided with a pair of contact blocks 30 formed of any suitable insulating material and which are secured by screws 3| or other suitable means, to the slides adjacent the inner sides thereof in longitudinal spaced relation.

Each of the blocks 30 is provided with a yielding contact member 32 which, in this instance, is composed of a fiat spring positioned longitudinally of the inner vertical face of the block, and is secured to said blocks at its outer ends by means of screws 33.

The inner adjacent end portions of the contact members-32 of each pair of

blocks

3,0 terminate in slightly spaced relation and are curved, as illustrated in Figure 3, to extend a short distance beyond the inner vertical face of the blocks and register with respective grooves 34 formed in the blocks which permit the contact members to flex towards said block when engaged by a cooperating relatively rigid contact member 35.

This contact member 35 is secured in insulated relation to the intermediate slide I4 at the opposite end to that at which the tie bar 22 is pivoted. This contact member 35 is composed of brass or other suitable conducting material and is arranged to extend transversely of the slide I4 between the slides III and II, and has the outer ends thereof terminating in the vicinity of the contact members 32 and normally" positioned intermediate the adjacent ends of said contact members, but out of the electrical connection therewith. l

The

contact members

35 and 32 are so arranged that one or the other of the movable contact members 32 will be engaged by the contact member 35 upon a very slight'longitudinal movement of the slide l4, or of one or the other or both of the slides I9 and II for making electrical connection therebetween.

Each of the slide members IO, N, I2 and'l3 may be moved longitudinally in one direction or the other along their

respective guide ways

5, 6, I or 8 and independently of 'each' other by their respective thermostatic control units I8, I9, 29 or 2| in the following novel manner.

As the thermostatic units l8; I9, 20 and 2| are constructed and operated similarly there will bebut one of these units described, namely, the thermostatic unit designated l8, which is operably connected with the slide l0, and which is shown more particularly in Figures 2 and 4. This thermostatic unit I8 consists of a thermo-sensitive member or bulb and an actuating member connected in a fluid-tight manner. The thermosensitive member or bulb is partially filled with 3 units comprising the instrument upon a a volatile fiuid, the temperature and pressure characteristics of which are suitable for range and scope of the instrument. The actuating member consists of a pair of pressure operated Sylphon tubes or bellows 38 and 39, each comprising a base 40 and a head 4| connected by a corrugated tube 42 which is secured at respective ends to the base 40 and head 4| in a fluid-tight manner.

The bellows 38 and 39 are secured to the platform 2 positioned below the respective end of the table I at which the thermostatic unit is positioned by means of, in this instance, three bolts or screws 43 which extend through suitable holes provided in the base 40, and are screw-threaded in platform 2. The supporting platforms 2 may consist of substantially rectangular flat members 44 composed of metal, wood or the like, and may as shown, have a pair of pendant legs 45 positioned near either end thereof, and which are tied together at their lower ends by a suitable foot or bar member 46 adapted to support the platform 2, and therefore, the remainder of the shelf or other suitable supporting means.

Each bellows head 4| is provided with an open- :ing 41, and each opening 41 may be closed in a fluid-tight manner by a suitable plug 48 screwthreaded therein.

Each head 4| is also provided with a pair of upwardly projecting spaced lugs or ears 50 which have secured in the outer ends thereof, a fulcrum bar composed of tempered steel or the like. These bars 5| extend between the ears, as shown more particularly in Figure 5, and are triangular in cross section with one of the wedgeshaped edges arranged at the top thereof for pivotally supporting an equalizing bar 52 which is positioned between the ears 58, and extends from over one Sylphon tube to the other Sylphon tube.

This equalizing bar 52 is provided with a plurality of, in this instance, four wedge-shaped fulcrum bars as 53, 54, 55 and 56. These fulcrum bars are made substantially similar to the fulcrum bar 5| and extend a relatively short distance beyond either side face of the equalizing bar.

52 is pivotally connected .with

crum 54 is positioned a short distance from the other end of said equalizing bar and each of the fulcrums is pivotally connected with the respective fulcrum bars 5| connected with the bellows by a pair of crescent shaped pivotal links 51 composed of tempered steel or the like, and positioned one at either side of the equalizing bar 52 and between the respective ears 50. (See Figure 8).

A third fulcrum'bar as 55 is mounted in the equalizing bar 52 at the end adjacent the fulcrum bar 54 for pivotally connecting the bar and therefore, the

bellows

38 and 39 with a suitable slideactuating mechanism presently described.

The fourth fulcrum bar as 56 is connected with the equalizing bar 52 midway between the two end fulcrum bars 53 and 55. The equalizing bar the platform 2 by a pair of fulcrum links 58 also composed of tempered steel, and which have their lower ends pivotally engaging thelower knife-like edge of a fulcrum bar 59 mounted to extend outwardly from opposite sides of an upwardly extending arm 60 secured to or made integral with the platform 2. I It will thus be seen by referring more particularly to Figure 2, that the equalizing bar 52 is supported at unequal distances either side of its center, that is, the fulcrum 56, by the respective beilows 38 and 39, while the equalizing bar is maintained against bodily upward movement by the platform 2 through the medium of the fulcrum links 58 at a point equidistant from either end of the fulcrums 53 and 55 so that as equal forces are applied to the equalizing bar 52 by the gas pressure in each Sylphon tube, there will be a slight rocking movement of the equalizing bar about the central fulcrum 56 due to the differences in leverages of the'tubes thus obtained until a balance in forces is reached in a manner hereinafter more fully explained.

This pivotal movement of the equalizing bar 52 is utilized to reciprocatethe particular slide as I 0 conn'ected with the thermostatic unit in the following novel manner.

Since the temperature pressure characteristics of a volatile fluid are such that the pressure increases in progressively increasing increments with equal increments of temperature, and since it is desirable that the registering member of an instrument of this kindbe moved with a uniform motion along its path to correspond with uniform changes in temperature, it is evident that a compensating mechanism must be interposed between the actuating member of the thermal coupleand the registering member of the unit.

It is also essential that the registering member assumes a definite position for any definite temperature; therefore, the forces acting through the compensating mechanism must'be in static balance at any of the instrument.

It may be conceived that the instrument is divided into two portions, the actuating side which is subjected to unequal increments of pressure with equal increments of temperature, and the registering side having equal increments of motion but actuated by unequal increments of pressure.

Between the two sides is interposed the comtemperature within the range pensating mechanism consisting of a pair of cooperating cam levers 62 and H so designed and so disposed one to the other that the force due to the pressure within the actuating member of the thermal couple is transmitted through the cooperating cam levers and is held in static balance by an opposing force provided in connection with the registering side of the instrument.

Since a freely suspended weight subject to gravitation is simple and unvarying in intensity, this has been chosen as the method whereby the force transmitted from the actuating member,

tubes

38 and 39 of the thermal unit, is opposed and balanced.

A pair of verticallydisposed fulcrum links 60 is fulcrumed at their lower ends to the fulcrum bar 55 positioned at the outer free end of the equalizing bar 52 while the upper ends of these links are pivotally connected with a fulcrum bar 61 secured to a cam lever 62 and which extends from opposite sides of the lever and is positioned at a relatively short distance outwardly from the axis thereof.

This cam lever 62 is secured in any suitable manner to a horizontally disposed rock shaft 63 which, in turn,'is journaled at the lower side adjacent one end of a pendant lever supporting frame 64.

This frame 64 is comprised of a base 65 having a pair of spaced downwardly extending sides 66. The frame 64 is secured by screws 61 or other suitable means to the bottom of the table I beneath and at one side of the slide guideway with which the control unit is adapted to operate as, in this instance, guideway 5. (See Figures 2 and The rock shaft 63, in this instance, is journaled in a pair of roller bearings 68 mounted, one in the lower face of each side wall 66 of the frame 64 at one end thereof.

The cam lever 62, inthis instance, is mounted upon the shaft 63 between the side walls 66 of said frame, and therefore between the bearings 58, and extends outwardly in a substantially horizontal plane from the shaft 53 away from the frame 64 to form an arm 69 upon which is adjustably mounted a suitable weight H! which is adapted to counter-balance the cam lever 62. This cam lever proper extends outwardly from the shaft 63 towards the opposite end of the frame 64, and is adapted to co-operate with a second cam lever H which extends over the first mentioned cam lever 62 in contact therewith for actuating a second rock shaft I2 which is journaled at the opposite end of the frame 64 to that in which the shaft 63 is jpurnaled.

This shaft 12, like the rock shaft 63, is journaled in roller bearings similar to the bearings 68 for the shaft 63 which are mounted in the lower face of each side wall 66 of the frame 64 in the same manner in which the bearings 68 are mounted for the shaft 63. r

A gear segment 13 is secured to the rock shaft 12 adjacent one side of the frame 64 and extends upwardly from the shaft through a suitable elongated slot 14 provided in the table I between the guide rails constituting the guide members 5.

The gear teeth as 15 of the gear segment 13 are in meshing engagement with corresponding rack teeth 16 formed on-the bottom face of the slide member Ill so that any rocking movement of the gear segment 13 will produce a corresponding longitudinal movement of the slide I 0.

The gear segment 13 is provided with a pendant arm H which extends below the axis of the segnected by a cable 80 to the arcuate outer vertical edge of a rock arm 8| which is secured to the rock shaft 12 at the opposite side of the frame 64 to that at which the segment gear I3 is positioned.

The weight 19, in this instance, is composed of a receptacle 82 adapted to contain relatively small particles of weighing material 83 such as shot, so that a very accurate adjustment may be obtained by the addition of more or less weight to the rock arm 8|.

The outer curved surface of the rock arm 8| is made concentric with the shaft 12 so that an even pull will be exerted by the weight upon the rock arm and shaft 12 throughout the entire range of movement of said rock arm.

It will be noted by referring to Figure 2, that the adjacent contacting edges of the cam levers B2 and 1| are curved from the point of contact thereof outwardly in opposite directions, and this curvature is such that the point of contact between the two cam levers B2 and H will always be in a plane passing through the axes of the two

rock shafts

63 and 12.

The contacting curvatures of the two cam arms 62 and H are so designed that equal increments of temperature, to which the thermometer bulb 92 may be subjected, will cause a corresponding equal increment of rotation of the follower cam arm 1| and, therefore, of the gear segment 13.

Also the contacting curvatures of the two cam arms are so plotted that the slide, as ID, actuated thereby, is caused to be moved along the guideways in the same relation to the eo-acting slides as the scales on a thermometric chart corresponding to the slides bear to each other, as will hereinafter be more apparent.

It may now be understood that the unbalanced force exerted upon the equalizing bar 52 by the gas pressure in the Sylphon tubes, will exert a reactive pull in the links Ell which will be transmitted through the cam levers 62- and H, the rack shaft I2 and the rock arm 8| to the Weight As previously explained, the point of contact between the cam levers 62 and II will always be at varying points along a straight line between the axes of rock shafts B3 and 12; therefore, the ratio of leverages interposed between the pull exerted by the fulcrum links 60 and .the weight 19 will vary with the increase or decrease in the intensity of said pull.

As a result of this construction and the curvilinear form of the contact surfaces between the cam levers, the constant weight 19 will always hold in equilibrium varying intensities of pull exerted upon the links 60 by the lever 52.

' 0f the two Sylphon tubes, which are equal in sectional area and are subjected always to equal gas pressures which will vary in accordance with the temperature to which their respective thermo-sensitive member as a thermometer bulb 92, is subjected, the tube 38 supplies the operating force. The function of the Sylphon tube 39,

whose point of contact with the equalizer bar than the contact point of the distance from the fulcrum 58 operating tube 38, force exerted by 52 is at a shorter is to partially counteract the the operating tube 38. Thus, a very sensitive but positive pivotal movement of the equalizing bar 52 is produced.

From the foregoing, it will be evident that the slide, as III, will assume a certain and definite position for any definite temperature to which the thermometer bulb' 92 may be subjected.

Owing to the fact that the corrugated tubes 42 of the bellows'38 and 39 are of metallic construction, a certain definite resistance will be exerted against any movement of either expansion or contraction, this resistance being similar to the action of a coil spring.

In order to counter-balance this structural resistance which otherwise would impair the accuracy of the unit, I. have provided a. pair of counter-weights 85 which are pivotally mounted upon respective fulcrum bars 86 secured to respective, upwardly extending, rock arms 81 psitioned one at either side of the frame 64 and mounted upon the adjacent ends of the rock shaft 63 to move therewith.

In adjusting the instrument, the

bellows

38 and 39 are allowed to assume their free or normal length, being'neither in compression nor extension.

When the bellows 38 and 38 are in this position, the equalizer bar 52 is suspended in a horizontal position by the links 51, the center line of the gear segment 13 assuming and the slide ID midway of its travel in. either direction. The arms 87 are then positioned vertically over the axis of the rock shaft 63 thus supporting the weights 85 in such a manner that their centers of, gravity will be in a plumb line above the axis of the rock shaft 83 and, therefore, are exerting no tendency to rotate said shaft.

When, in operation, the gas pressure in the

bellows

38 and 39 issuificient to overcome the pull exerted by the weight 79, acting through the mechanism, bellows 38 will extend,

equal and opposite to the structural resistance offered by bellows 38 in extending and bellows 39 in compressing.

Conversely, should the pull exerted by the weight 19 through the intermediate mechanism be suflicient to overcome the action of the gas pressure, in. the

bellows

38 and 39 when the unit is in its mid-position, the bellows 38 will be comthis shaft by-a force equal and opposite to the structural resistance oifered by the bellows.

It is now evident that I have provided a very delicately balanced extremely sensitive mechanism for. actuating the slide l0, and as the slides ll, l2 and I3 are each provided with a. similar thermostatic actuating unit and with the Sylphon bellows 38 and 39 of each unit connected with a. hereinbefore mentioned thermosensitive member such as a dry bulb thermometer or with a wet bulb thermometer, .it is also obvious that each of these slides willa vertical position manner such as a tube 90 which is connected at one end with the interior of each bellows by means of a relatively short pipe or tube 98' which extends upwardly through a respective aperture 9| provided in the platform 2, and are screw-threaded in the center of respective base members 48 while the other end of the tube 38 is operably connected in any well known manner to the respective dry or

wet bulb thermometer

92 or 93, as the case may be.

These bulbs for operating the various thermostatic actuating units may be supplied with any suitable liquid, whose boiling point temperatures and pressures range within the desired limits, such as ethyl chloride.

In Figure 10, I have illustrated diagrammatically a conventional air conditioning system in connection with an inclosure,together with my novel air conditioning control instrument and the means by which this instrument may be operably connected with the system.

The air, conditioning unit, as illustrated, consists of an air conditioning chamber h connected at one end by a suitable conduit 1' with the inclosure 9. The other end of the chamber it may be connected, as shown, by a second conduit :1 to the conduit 2 for admitting air to the chamber ahead of a plurality of water sprays k and a series of baiiie plates k positioned in the chamber intermediate its ends.

The sprays k are supplied from a refrigerated source 1 through a water is withdrawn from the spray chamber h through the pipe 11. and. returned to the source of refrigeration for re-circulation.

A by-pass connection 1) is provided between the terposed a valve 0 thus permitting the water drained from the chamber 11 to be returned to the refrigerated source or to be delivered directly to the circulating pump m. By manipulating the valve 0, any desired temperature of the spray water may be obtained, ranging from the cold temperature of the refrigerated source, to the warmer temperature of the water drained from the chamber 11,.

In accordance with well established thermal laws, the maximum amount of vapor possible to be present with a definite volume of air, is a function of the temperature of the mixture; the higher the temperature, the greater the amount of vapor.

If the atmosphere in an inclosure is to be maintained at somedeflnite temperature and degree of relative humidity, all moisture introduced therein, in excess of the desired amount, must be removed by the circulating air. In order that the circulating air may have the capacity for absorbing this excess vapor, its temperature upon leaving the air conditioning unit must be sufiiciently below that of the inclosure so that its vapor at saturation, plus the excess vapor to be absorbed, will result in a mixture of the desired relative humidity when at the temperature of the inclosure.

r In other words, the greater the amount of vapor to be removed from the inolosure, the lower must be the temperature of the circulating air leaving the air conditioning unit and, consequently, the temperature of the water in the sprays lc must vary inversely with the amount oil-vapor to be removed from the inclosure.

Since the degree of relative humidity affects the reading of a wet bulb thermometer without in any way changing that of a dry bulb thermometer, the temperature of the spray water I: may

be varied to suit varying conditions of humidity by operating the by-pass valve by means of a thermostat responsive to wet bulb conditions. To

accomplish this, the operating stem of the valve 0 may be connected to a magnetic core 11 operably disposed to function forward and backward under the alternate influence of two oppositely positioned solenoids r.

A fan q is'connected with the air conditioning chamber h, as shown, for drawing air from the inclosure through said conditioning chamber, and it has an outlet conduit w connecting the fan with the inclosure y for returning air to said inclosure.

A suitable damper s is inserted in the by-pass conduit 7 intermediate its ends. For opening and closing the damper s, said damper is operably connected to a magnetic core t designed to function forward and backward under the alternate the inclosure and this must equal the heat injected therein.

' By manipulating the damper s, a varying quantity of air may be forced to pass through the cooling spray water in accordance with the refrigeration requirements of the inclosure. Since the heat introduced within the inclosure affects directly the dry bulb thermometer and only indirectly the wet bulb thermometer, as that reading is modified by the amount of vapor present, the refrigeration requirements will be indicated by the rise or fall of the dry bulb temperature above or below a predetermined point. Therefore, to maintain a predetermined definite temperature, with varying amounts of heat introduced into the inclosure, it is only necessary to manipulate the damper s in the by-pass conduit 7' by means of a thermostat responsive to a dry bulb temperature.

Each of the solenoid coils r and u may have the electric circuit therefor automatically controlled by my novel control instrument for opening or closing the valve 0 and the damper s in the following manner and thereby automatically controlling the conditions of the air in the inclosure 9: 1

The contact bar 35, connected with the slide l4 may be, as shown, electrically connected with one side of a source of potential as a battery B or from an outside source of current. The terminals 32 carried by the slide III of the dry bulb operated thermostat I8 may be electrically connected each with its respective solenoid u, as shown, which, in turn, are electrically connected with the opposite side of the battery B.

Likewise, each of the terminals 32 attached to the slide II of the wet bulb operated thermostat I9, may be electrically connected to its respective solenoid 1', as shown, which are also connected to the battery B. Thus a contact of the bar 35 with either of the terminals 32 attached to the slide III will produce an electric current through its respective solenoid u and the magnetic force thus set up will move the core t in a corresponding direction to open or close the dampers. Also a contact of the bar 35 with either of the terminals 32 carried by the slide II will produce an electric current through its respective solenoid 1' moving maintained in an inclosure by the manual manipulation of a thermostat furnished as part of the equipment and which is responsive to the temperature of the inclosure irrespective of the number of people in the inclosure, but the relative humidity and consequently, the effective temperature constantly varies in proportion to the number of persons present.

Although an infinite variety of dry and wet bulb temperatures may produce one or the same effective temperature, and may feel equally comfortable, they do not all seem to be. conducive to health, and therefore, for ideal conditions, a fairly constant degree of relative humidity should be maintained, and this has been determined through extensive experimental processes to average approximately 55%. In other words, instead of maintaining a constant dry bulb temperature in an auditorium or inclosure a constant degree of relative humidity should be the object of air conditioning.

It is also quite generally conceded that the best average effective temperature which has been found to produce the maximum comfort for persons normally clothed, at rest, and instill air, is 66 degrees, and since the sudden contrast be.

tween this condition and the high effective temperatures to be experienced on the outside durfective temperature outside and 66 degrees effective temperature.

In Figure 11 of the drawings is illustrated a I thermometric chart for comfort which shows the relation between the outside effective temperatures and the conditions to be maintained inside, if the inside effective temperature is maintained midway between the outside effective temperature and 66 degrees effective temperature, and at the same time maintaining a relative degree of humidity on the inside at 55%. By referring to this chart, it will be noted that the vertical lines e' represent the outside effective temperatures, the oblique full lines a and I)" represent the inside dry bulb temperature, and the inside wet bulb temperature respectively, and that the oblique broken line i represents the inside efiective temperature.

Operation bulb 93 also positioned in the outside atmosphere,

it will be evident that these slides I2 and I3 will be moved longitudinally along their respective guides I and 8 in accordance with any variation in the temperature of the outside atmosphere, and also with any variation in the relative degree of moisture.

It may now be observed that due to the particular construction and operation of the respective thermostatic actuating units connected therewith, these slides will have a longitudinal movement along their respective guides depending upon the act-ion of the atmosphere upon the respective bulbs, and that the movement of the slides will be independent of each other, and at the same time, will have the same relative position one to the other which the outside dry and wet bulb scales 0 and d bear to each other.

It is also evident that the bar 22 being pivotally connected with the slide I4 and also having a free sliding engagement with points fixed upon the slides I2 and I3, the slide I4 will be actuated by both or either slide I2 or I3 along its guide 9. Therefore, the slide I4 will assume a definite position relative to the positions of the dry and wet bulb slides I2 and I3 due to the angular relation of movements of the slide I4 and the slides I2 and I3, which will indicate the outside effective temperature corresponding thereto, which is indicated by the scale e adjacent the slide II in Figure 1, and by the vertical lines e in Figure 11.

It will also be understood that by connecting the thermostatic actuating unit for the slide ID with a dry bulb 92 positioned within the inclosure, and by connecting the thermostatic actuating unit for the slide I I with a wet bulb 93 positioned in any suitable place for being effected by the degree of moisture contained in the inclosure g as in the air outlet conduit 7' leading to the conditioning chamber h, these slides will be moved along their

respective guides

5 and 6 in the same relative relation which the inside dry bulb temperature scale a and the inside wet bulb temperature scale b bear to each other on the thermometric comfort chart. (See Figure 11.)

In other words, if the outside wet and dry bulb temperatures are such as to produce an out-= side effective temperature of eighty degrees, which as indicated by the scales a and c in Figure 1, may be 71% degrees and 90 degrees respectively, then the inside dry bulb temperature will be 78 degrees, and the inside wet bulb temperature will be 66 /2 degrees as indicated by the scales a and b respectively in Figure 1, or by lines a and b in Figure 11, and therefore, the inside effective temperature will be 73 degrees, as indicated by the chart in Figure 11, with the relative humidity of and the contact bar 35 will be positioned intermediate the respective yielding contact members 32 connected with the slides I II and II.

Should either the temperature in the inclosure or the percentage of moisture thereof vary, a corresponding movement of the respective dry or wet bulb slides I0 and I I will result, and the contact bar 35 will be brought into electrical connection with one or another of the yielding contact members 32.

' If, for instance, an accession of heat is introduced into the inclosure, the dry bulb temperature will rise, the slide ID will move outwardly and the lower terminal 32, as viewed in Figure 10, will contact with the bar 35, thus setting up an electric current through the lower solenoid u. The core t will be pulled downwardly, closing the damper s and forcing an increased volume of air through the cooling sprays It thus increasing the amount of refrigeration furnished the inclosure to meet the said accession of heat. Y

Due to the increased quantity of air passing through the sprays, the temperature of the water will rise andthe temperature of the air leaving the conditioning chamber it will be increased. -Its moisture carrying capacity will thus be reduced,

increasing the wet bulb temperature and the slide II will likewise move outwardly effecting a contact between the bar 35 and the lower contact terminal in slide I I. An electric current will be sent through the upper solenoid r which will (See Figure 1.)

move the magnetic core 1) upwardly to close the valve 0 thus increasing the amount of water drawn from the refrigerated source and injected into the sprays k. The temperature. of the sprays It will be lowered and consequently the temperature of air leaving the same will be reduced to the required point.

It will thus be seen that an increased demand for refrigeration will be met by passing an increased quantity of air through the cooling spray 1 water and by an increased range of temperature in an unvarying quantity of sprays.

These conditions will prevail until the predetermined balance is reached when the slides I0 and II will again assume such positions that the 1 contact between the bar 35 and the terminals 32 is again discontinued.

Conversely, should the demand for refrigeration in the inclosure g be decreased, the slide ID will move inwardly making contact with the upper terminal in Figure 10,- when -a current will be set up through the upper solenoid u, opening the bypass damper s thus reducing the quantity of air passing through thesprays k. This action will result in lowering the temperature of the air leav- Any movement of the slide I4 will bring the bar 35 into contact with one or the other of the terminals attached to the slides Ill and II with the consequent effect of modifying either or both the temperature or volume of air passing through the conditioning chamber h.

Therefore, any variation in conditions of the outside atmosphere will be transmitted through the effective temperature slide I4 and the coactive slides I0 and II to maintain an atmospheric condition within the enclosure which shall be in definite relation to the effective temperature prevailing outside atany time. 1

It will, therefore, be seen that any changes occurring in either the dry bulb temperature or the wet-bulb temperature, or in both, in either the outside air or the inside air will, through the respective dry or wet bulbs, so affect the corresponding slides in my novel control instrument as to cause the air conditioning system to automatically maintain an inside effective temperature which will have the same relation to the outside effective temperature as the inside effective temperature scale or curve bears to the outside effective temperature scale or curve, as indicated in Figure 11.

It is evident that while I have illustrated and i 1 described a particular embodiment of my invention and the means of operably connecting my novel control instrument with a specific air conditioning system, this may be altered materially in that an entirely different electrical hook-up may be employed, or the slides Ill and II may be operably connected with other units of ,the conditioning system, and that various changes in construction of my control instrument and in the form and relation of the parts thereof may readily be made without departing from the spirit of this invention, as set forth in .the appended claims.

I claim:'

1. A control instrument for air conditioning systems comprising an outside effective temperature slide, operating means connected with the slide for moving said slide in accordance with the effective temperature curve of the outside air, and means co-acting with the slide and actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

2. A control instrument for air conditioning systems comprising an outside effective temperature slide, operating means connected with the slide for moving said slide in accordance with the effective temperature curveof the outside air, a dry bulb slide, a wet bulb slide, means operated by the inside dry bulb temperature for moving the dry bulb slide in accordance with the inside dry bulb temperature, a separate means operated by the inside wet bulb temperature for moving the wet bulb slide in accordance with the inside wet bulb temperature, and co-operating means connected with each of said slides and adapted upon relative movement of the slides, to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

3. A control instrument for air conditioning systems comprising an outside effective temperature slide, means connected with the slide and actuated by the dry and wet bulb temperatures of the outside air for moving said slide in accordance with the effective temperature curve of the outside air, and means co-acting with the slide and actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

4. A control instrument for air conditioning systems comprising an outside effective temperature slide, means connected with the slide and actuated by the dry and wet bulb temperatures of the outside air for moving said slide in accordance with the effective temperature curve of the outside air, and means co-acting with the slide and thermostatically actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective'temperature.

5. A control instrument for air conditioning systems comprising an outsde effective temperature slide, thermostatic operating mechanisms connected with the slide and actuated by the dry bulb temperature and wet bulb temperature of the outside air for moving said slide in accordance with the effective temperature curve of the outside air, and means co-acting with the slide'and actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for mainta ning the inside effective temperature in accordance with an inside effective temperature curve. l

6. A control instrument for air conditioning systems comprising an outside effective temperature slide, a dry bulb slide, a wet bulb slide, means operated by the outside dry bulb temperature for moving dry bulb slide in accordance with the outside dry bulb temperature, separate means operated by the outside wet bulb temperature for moving the wet bulb slide in accordance with the outside wet bulb temperature, means connecting the effective temperature slide with said dry and wet bulb slides whereb'y the effective temperature slide will be moved by the dry and wet bulb slides in accordance with the effective temperature curve of the outside air, and means coacting with the effective temperature slide and actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

7. A control instrument for air conditioning systems comprising an outside effective temperature slide, a dry bulb slide, a wet bulb slide, means operated by the outside dry bulb temperature for moving dry bulb slide in accordance with the outside dry bulb temperature, separate means operated by the outside wet bulb temperature for moving the wet bulb slide in accordance with the outside wet bulb temperature, means connecting the effective temperature slide with said dry and wet bulb slides whereby the effective temperature slide will be moved by the dry and wet bulb slides in accordance with the effective temperature curve of the outside air, a second dry bulb slide, a second wet bulb slide, means operated by the inside dry bulb temperature for moving said second dry bulb slide in accordance with the inside dry bulb temperature, a separate means operated by the inside wet bulb temperature for moving said second mentioned Wet bulb slide in accordance with the inside wet bulb temperature, and co-operating means connected with the effective temperature slide and with the second mentioned dry and wet bulb slides adapted upon relative movement of either or both of the second mentioned slides and the effective temperature slide to automatically control the operationof an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

I 8. A control instrument for air conditioning systems comprising an outside effective temperature slide, a dry bulb slide and a wet bulb slide mounted to move in parallelism and at an angle to the effective temperature slide, means operated by the outside dry bulb temperature for moving the dry bulb slide in accordance with the outside dry bulb temperature, separate means operated by the outside wet bulb temperature for moving the wet bulb temperature slide in accordance with the outside wet bulb temperature, means connecting the effective temperature slide with said dry and wet bulb slides whereby the effective temperature slide will be moved by the dry and wet bulb slides in accordance with the effective tempera ture curve of the outside air, and means coacting with the effective temperature slide and systems comprising an outside effective temper-ature slide, a dry bulb slide and a wet bulb slide mounted to move in parallelism and at an angle to the effective temperature slide, means operated by the outside dry bulb temperature for moving the dry bulb slide in accordance with the outside dry bulb temperature, separate means operated by the outside wet bulb temperature for moving the wet bulb temperature slide in accordance with the outside wet'bulb temperature, means connecting the effective temperature slide with said dry and wet bulb slides whereby the effective temperature slide will be moved by the dry and wet bulb slides in accordance with the effective temperature curve of the outside air, means pivotally connected with the effective temperature slide and slidably connected with the said dry and wet bulb slides whereby a movement of either of the dry or wet bulb slides will produce a differential movement of the effective temperature slide corresponding to the relation the outside dry and wet bulb temperatures have to the outside effective temperature curve, and means co-acting with the effective temperature slide and.

actuated by the dry and wet bulb temperatures of the inside air adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside effective temperature.

10. A control instrument for air conditioning systems comprising an outside effective temperature slide, operating means connected with the slide for moving said slide in accordance with the efi'ective temperature curve of the outside air, a dry bulb slide and a wet bulb slide mounted to move in parallelism with the effective temperature slide, means operated by the inside dry bulb temperature for moving the dry bulb slide in accordance with the inside dry bulb temperature, separate means operated by the inside wet bulb temperature for moving the Wet bulb slide in accordance with the inside wet bulb temperature, and co-acting means connected with the effective temperature slide and with said dry and wet bulb slides adapted to automatically control the operation of an air conditioning system for maintaining the inside effective temperature at a predetermined relation to the outside temperature.

' systems comprising an outside'effective temperature slide, a dry bulb slide and a wet bulb slide mounted to move in parallelism and at an angle to the effective temperature slide, means operated I by the outside dry bulb temperature for moving the dry bulb slide in accordance with the outside dry bulb temperature, separate means operated by the outside wet bulb temperature for moving the wet bulb temperature slide in accordance with i the outside wet bulb temperature, means connecting the effective temperature slide with said dry and wet bulb slides whereby the effective temperature slide will be moved by the dry and wet bulb slides in accordance with the effective temperature curve of the outside air, means pivotally connected with the effective temperature slide and slidably connected with the said dry and wetbulb slides whereby a movement of either of the dry or wet bulb slides will produce a differential movement of the effective temperature slide corresponding to the relation the outside dry and wet bulb temperatures have to the outside eflective temperature curve, a second dry bulb slide and a second wet bulb slide mounted to move in parallelism with the effective temperature slide, means operated by the inside dry bulb temperature for moving the dry bulb slide in accordance with the inside dry bulb temperature,

11. A control instrument for air conditioning separate means operated by the inside wet bulb temperature for moving the second mentioned wet bulb slide in accordance with the inside wet bulb temperature, and co-acting' means connected with the effective temperature slide and with the second mentioned dry and wet bulb slides adapted to automatically control the operation of an air conditioning system for maintaining mined relation to the outside effective temperature. I I

12. A temperature control instrument in comvthe inside effective temperature at a predeterbination with an air conditioning system comatmosphere dry bulb temperature, a separate means for shifting the other pair of said contact members in conformity with the inside atmosphere wet bulbtemperature, and means electrically connecting each pair of contactmembers with a respective control unit of said conditioning system.

13. In a thermostatic unit responsive to temperature variations, a thermostatic couple consisting of a liquid-containing member adapted to be exposed to temperature variations, a vaporcontaining member expansively and contractively responsive to variable vapor pressures, means connecting said liquid-containing member with the vapor-containing member in a fluid-tight manner, an actuating cam, means operably connecting said cam with the vapor-containing member, a follower cam adapted to be operated by said actuating cam, a counter-balancing weight associated with the cams adapted to restrict the motion of said vapor-containing member and to hold the unit in equilibrium against varying pressures within the thermostatic couple.

14. In a thermostatic unit responsive to variable vapor pressures produced by temperature variations, a thermostatic couple, an actuating cam-shaped lever mounted upon a rock shaft, operating means connecting said cam lever with said thermostatic couple, a follower cam-shaped lever mounted upon a second rock shaft, said cam levers being so disposed in relation to each other that the point of contact between said levers will assume variable positions intermediate the two supporting shafts, and a counter-balancing weight adapted to restrict the motion of said follower cam lever, the form of the contacting surfaces of the two cam levers being such that equal increments of temperature variation will produce equal increments of angular motion in the follower lever.

15. An instrument for controlling air temperature and humidity conditions comprising a movable member having a uniform increment of motion corresponding to equal increments of temperature to which the thermo-sensitive member of a thermal couple is exposed, an actuating member of the thermal couple designed to expand and contract, responsive to unequal increments of pressure for equal increments of temperature to which the thermo-sensitive couple of the member is exposed, a pair of co-operating cam levers constrained to rotate each about its respective shaft, the curvilinear surfaces of contact of said levers being such that any expansive or contractive movementof the actuating member of the thermal couple will be translated into uniform motion of the movable member proportional to uniform changes of temperature to which the thermo-sensitive member of the thermal couple is exposed, operating means connecting the actuating member of the thermal couple with one of the cooperating cam levers, and other operating means connecting the second cam lever with the movable member and an opposing force of uniform intensity so disposed that acting through varying ratios of leverages pro- J duced by the action of the pair of co-operating cam levers, the instrument will always be in static balance for each definite temperature to which the thermo-sensitive member of the thermal couple may be exposed. 16. An instrument for controlling air temperature and humidity conditions comprising two movable members, one member actuated by a thermostatic couple adapted to utilize evaporative pressure generated 'by a volatile fluid and responsive to dry bulb temperature changes, the other member actuated by a thermostatic couple adapted to utilize evaporative pressure generated by a volatile fluid and responsive to wet bulb temperature changes, a pair of cam levers operably connecting each movable member with the actuating member of its respective thermostatic couple, electric contact means inter-connecting the two movable members whereby electrical operating means may be set in motion to manipulate its respective function of an air conditioning unit to maintain a predetermined relation of wet bulb temperature with anexistent dry bulb temperature.

, 17. An instrument for controlling air tem-.

perature and humidity conditions comprising a thermostatic instrument, one registering member of which is moved responsive to dry bulb tem- 'peratures of the outside air, a second thermoit moves responsive tothe effective temperatures l of the outside air, a third thermostatic instrument, the registering member of which moves responsive to a dry bulb temperature within an inclosure, a fourth thermostatic instrument, the registering member of which moves responsive to wet bulb temperatures within the enclosure, two electrical contact means attached-t9 the effective temperature registering member adapted to engage with correlating contact means attached to the inside dry bulb and wet bulb registering members, and means electrically connecting the contacts with a respective control unitpf the conditioning apparatus whereby the dry bulb and wet bulb temperatures of the enclosure are regulated in such-relation that the effective temperature of the enclosure is maintained at a predetermined relation to the outside effective temperature. I

18. An instrument for controlling air temperature and humidity conditions comprising a thermostatic unit in combination with an air conditicning system, whose registering member is responsive to dry bulb temperatures in an enclosure, a second thermostatic unit whose registering member is responsive to wet bulb temperatures in the enclosure, the rate of movement of the dry bulb and wet bulb registering members in relation to each other being the relation which varying dry bulb temperatures bear to corresponding wet bulb temperatures when the relative humidity in the enclosure is to be maintained according to a predetermined amount in relation to the dry bulb temperature, adjustable means electrically co-acting with the dry bulb and wet bulb registering members whereby the dry bulb registering member operates a control unit of the conditioning system to vary the amount of refrigeration supplied to the enclosure and the wet bulb registering member operating a control unit of the conditioning system to vary the temperature of air leaving the conditioning system.

19. An instrument for control-ling air temperature and humidity conditions in combination with an air conditioning apparatus comprising a thermostatic instrument, one member of which is responsive to dry bulb temperatures outside an enclosure and a second member responsive to wet bulb temperatures outside said enclosure,

means coactingwith the aforesaid dr bulb and wet bulb members for moving a registering member in differentialrelation to the movement of the aforesaid dry and wet bulb members, a third memberof a thermostatic instrument responsive to dry bulb temperatures within the enclosure, a fourth member'of the thermostatic instrument responsive to wet bulb temperatures within the enclosure, electrical contact means coacting between the difierential registering member and the inside dry bulb and wet bulb members whereby a respective control unit of said conditioning apparatus is regulated to vary the inside dry and wetbulb temperatures in accordance with varying conditions prevailing in the air outside the enclosure.

. I 20. In a device for controlling air temperature and humidity conditions. in an enclosure in combination with an air cooling apparatus and comprising means for circulating air through the enclosure and through said cooling apparatus, means for controlling the temperature of the air leaving the cooling apparatus, means for controlling the amount of air passing through the cooling apparatus, a registering member, of av thermostatic instrument responsive to dry bulb temperatures within the enclosure, a second registering member of a thermostatic instrument responsive to wet bulb temperatures within said enclosure whose rate of movement in relation to the movement of the first-mentioned registering member is proportional to the relation desired in the enclosure between wet bulb and dry bulb temperatures, coacting means between the two registering members whereby the means for controlling the temperature of air leaving the cooling apparatus is operated to vary said temperature, and adjustable means coacting with the dry bulb registering member whereby the means for controlling the amount of air passing through the cooling apparatus is operated to vary said amount.

21. In a device for controlling air temperature and humidity conditions in an enclosure'in combination with an air cooling apparatus and comprising means forcirculating air through the enclosure and through said cooling apparatus, means for controlling the amount of air passing through the cooling apparatus, means for controlling the temperature of the air leaving the cooling apparatus, a thermostatic instrument having two registering members respectively rewithout the enclosure mutually coacting to move a third registering member in differential relation to the movements of the aforesaid dry bulb and wet bulb registering members, two other registering members of the aforesaid thermostatic instrument respectively responsive to dry bulb and wet bulb temperatures within the enclosure and means coacting between the differential registering member with each of inside temperature registering members whereby upon relative movement between the inside dry bulb and wet bulb registering members with the differential registering member, the respective means for controlling the amount of air passing through the ,coolingapparatus and the means for controlling the temperature of the air leaving the cooling apparatus may be varied to maintain within the enclosure dry bulb and wet bulb temperatures in accordance with varying dry bulb and wet bulb temperatures existing outside the enclosure.

22. In a thermostatic unit responsive to unequal increments of vapor pressure produced by equal increments of temperature variations, a

thermostatic couple consisting of a vapor-containing element expansively and contractively responsive to variable vapor pressures, a pair of cam members operatively associated for positively transmitting motion from one to the other, operating means connecting the vapor-containingelement with the actuating cam member, and resistance means connected with one of the cam members adapted to exert an even pull upon said cam members throughout the entire range of movement thereof to restrict the motion of said vapor-containing element and to hold the unit in equilibrium against varying pressures within the thermostatic couple.

23. An improved method of temperature and humidity control of air in an enclosure which comprises determining the relation with the wet and dry bulb temperatures of the air inside the enclosure has to the efiective temperature of the air outside. the enclosure, varying the wet and dry bulb temperatures of a volume of air in accordance with such relative condition, so that when said volume of air is mixed with the air in the enclosure, the effective temperature of said enclosed air will be maintained substantially midway between a predetermined effective temperature and the effective temperature prevailing in the air outside the enclosure.

24. An improved method of temperature and humidity control of air in an enclosure which comprises determining the relation which the psychrometric condition of the air inside the en closure has to the eflective temperature of the air outside the enclosure, varying the wet and dry bulb temperatures of a volume of air in accordance with such relative condition, so that when said volume of air is mixed with the air in the enclosure, the effective temperature of said enclosed air will be maintained intermediate 66 degrees eiIective temperature and the effective temperature prevailing in the air outside the enclosure.

25. An improved method of temperature and humidity control of air in an enclosure which comprises supplying a volume of air to the enclosure, conditioning said volume of air by controlling the amount thereof which is passed through an air conditioning apparatus, in accordance with the relation which the efiective temperature of the air outside the enclosure has to the effective temperature of the air inside the enclosure so that when said volume of air is introduced into the enclosure, the effective temditioning apparatus in accordance with such rel-- ative condition to change the temperature and humidity of the stream of air so that when saidtreated stream of air mixes with the air in the enclosure, the effective temperature of air within the enclosure will be maintained intermediate a predetermined effective temperature and the effective temperature of the air outside said enclosure.

27. An improved method of temperature and humidity control of air in an enclosure which comprises passing a stream of air through an air conditioning apparatus having a spray chamber therein, determining the relation which the wet bulb temperature of the air inside the enclosure has to the efiective temperature of the air outside the enclosure, controlling the temperature of the spray in said chamber in accordance with such relative condition to change the dew point of the air, determining the relation which the dry bulb temperature of the air inside the enclosure has to the effective temperature of the air outside the enclosure, controlling the quantity of air passing through said spray chamber, in accordance with such latter relative condition to govern the temperature of the air leaving the conditioning apparatus, and then intro ducing said treated air into the enclosure.

28. A device for controlling the temperature and humidity of air in an enclosure which comprises an air conditioning apparatus having an air controlling means and an air cooling means,

means for withdrawing air from the enclosure,

passing said air through the air conditioning apparatus, and returning the conditioned air to the enclosure; a thermostatic instrument having a plurality of movable members, coacting operating meansfor one of said members respectively responsive to the dry and wet bulb temperatures outside the enclosure, whereby said member assumes variable positions corresponding to the eflective temperature of the outside air, operating means for a second member of the thermostatic instrument responsiveto the dry bulb temperature within the enclosurasaid second member acting in conjunction with the above first mentioned member for controlling the operation of the air control means, to regulate the amount of air passing through the air conditioning apparatus, to control the dry bulb temperature within the enclosure in a predetermined relation to the effective temperature of the air outside the enclosure, operating means for a third member of the thermostatic instrument responsive to the predetermined relation to the effective temperature of the air outside the enclosure.

29. A device for controlling the temperature and humidity of air within an enclosure which comprises an air conditioning apparatus, means for withdrawing air from the enclosure, passing said air through the air conditioning apparatus and returning the conditioned air tothe en'- closure, a thermostatic instrument responsive jointly to the dry and wet bulb temperatures of the air outside the enclosure and to the dry and wet bulb temperatures of the air inside the enclosure, and operatable means connecting the thermostatic instrument with respective regulating devices of the air conditioning apparatus, whereby the effective temperature of the air within the enclosure, is maintained in predetermined relation to the eflective temperature of the air outside the enclosure.

30. A control instrument for air conditioning systems comprising an outside efl'ective temperature member, means responsive to psychrometric conditions of the outside air for moving said member in accordance with the effective temperature variations of the outside air, and means coacting with said member responsive to pay-- chrometric conditions of the inside air adapted to automatically control the operation of an air conparatus for an enclosure, mechanism for controlling said apparatus comprising means responsive to psychrometric conditions of air, and a second means responsive to psychrometric conditionsoi air for modifying the operation of the first means,

at least one of said means being responsive to effective temperature conditions.

32. An improved method of temperature and humidity control of air in an enclosure which comprises determining the relation which the psychrometric condition of the air inside the enclosure has to the eflective temperature of the air outside the enclosure, varying the psychrometric condition 01' a volume of air in accordance with such relative condition, so that when said volume of air is mixed with the air in the enclosure, the eflective temperature of said enclosed air will be maintained intermediate between a predetermined efl'ective temperature and the effective temperature prevailing in the air outside the enclosure.

33. A control instrument for air conditioning systems comprising an outside efl'ective temperature member, means connected with .said memher and actuated by the psychrometric condition of the outside air for moving said member in accordance with the effective temperature of the outside air, and means coacting with said memher and actuated by the psychrometric condition of the inside air adapted to automatically control the operation of an air conditioning system for Y maintaining the inside efiective temperature at a predetermined relation to the outside eil'ec- ,tive temperature.

34. In combination with air conditioning apparatus for an enclosure, mechanism for controlling said apparatus comprising means responsive to changes in the psychrometric conditions of air for maintaining a predetermined effective temperature, and a second condition responsive means for modifying the operation of said control mechanism.

ALBERT E. BEALS.