US3410105A - Air conditioner - Google Patents

Description

Nov. 12, 1968 K. E. MARSTELLER AIR CONDIT IONER Filed Feb. 15, 1967 INVENTOR. Ki/VA/[Tb I. MlifffZZf/V l I I WMQZM m United States Patent 3,410,105 AIR CONDITIONER Kenneth E. Marsteller, Willow Grove, Pa., assignor to Philco-Ford Corporation, Philadelphia, Pa., a corporation of Delaware Filed Feb. 15, 1967, Ser. No. 616,310 Claims. (Cl. 62180) ABSTRACT OF THE DISCLOSURE An air conditioner having a temperature control system which, in addition to cyling the compressor between predetermined temperature limits, modulates air flow passing over the evaporator and into the room in accordance with room temperatures in excess of such limits. Modulation of air flow is accomplished by varying the speed of the fan motor inducing such flow, through a solid state electrical circuit controlled by an optical system comprising a lamp, a photocell, and an interposed shutter arrangement actuated by the thermostat.

This invention relates to air conditioners, and more particularly to improvements in temperature control systems for room air conditioners.

Temperature control can be achieved, to some degree, by varying the flow rate of room air over an air conditioner evaporator or cooling coil. If the air flow rates are maintained according to room temperatures falling within a very small temperature range, the room temperature can be held within such range as long as the existing cooling load requirements fall within the range of cooling capacity defined by the highest and lowest air flow rates. However, practical considerations, such for example as the tendency for ice to form on the coil at reduced loading, limit the minimum air flow rate to a value of about 50% of the maximum flow rate. An air flow rate of this order has been found to achieve a reduction in cooling capacity to a value of about 75% of maxim-um. For cooling loads requiring cooling capacity less than 75% of the maximum, means may be provided for cycling the cooling coil, as well as modulating the air flow rate, to maintain control of room temperature.

It is .a general objective of this invention to provide improved control apparatus affording a broad range of control, which apparatus is readily adaptable for use in a room air conditioner of otherwise conventional design.

Summary of the invention The present invention is directed to achievement of such control through a unique and simple modification of a conventional air conditioner thermostat mechanism of the type in which temperature variations are accompanied by motion of a linkage which, at the end of its travel, actuates the compressor energizing switch. It is proposed, in accordance with the invention, to drive a shutter or other suitable vane means by this linkage, which shutter is interposed between a light source and a photocell. Movement of the shutter is such that the linkage motion prior to switch acuation is translated into changes in photocell illumination. The resultant variable signal from the photocell is used to operate means for changing evaporator air flow from maximum to minimum. Preferably, the mechanism is so constructed and arranged that thesignal for minimum fiow will occur just prior to actuation of the compressor switch to deenergize the compressor.

Brief description of the drawing The manner in which the general objectives and advantages of the invention may best be achieved will be 3,419,105 Patented Nov. 12, 1968 understood from a consideration of the following description, taken in light of the accompanying drawing in which:

FIGURE 1 is a perspective view of a room air conditioner embodying the invention;

FIGURE 2 is a generally horizontal sectional view of apparatus seen in FIGURE 1, with parts broken away;

FIGURE 3 is a diagrammatic showing of control apparatus embodying the invention, and adapted for association with the air conditioner illustrated in the preceding figures; and

FIGURES 4 and 5 are somewhat more detailed fragmentary showings of a portion of the control apparatus illustrated in FIGURE 3.

Description 0 the preferred embodiment With more detailed reference to the drawing, there is seen in FIGURES l and 2 a window-mounted room air conditioner 10 including a cabinet '11 generally rectangular in configuration, and having a base portion 12 and a conventional decorative panel 13. The decorative panel comprises inlet and outlet room air passages for the air moving means to be more fully described. The inlet air passage includes grilles 1-4 and 18 disposed in the right hand region of panel 13, and in air flow communication with the inlet opening 17 of the indoor blower 16 of the air moving means. A filter 15 is positioned as shown, and is traversed by air flowing through grilles 14 and 18. The outlet passage includes a grille 21 disposed in air flow communication with an evaporator coil 22. A plurality of independently rotatable louvers 23 are disposed between evaporator coil 22 and the inside surface of outlet grille 21, and are operable to provide for selection of the direction of outlet air flow.

Evaporator coil 22, preferably of the finned type, is part of the usual refrigerating system including a motor compressor 24, a condenser 25, and associated conduits through which the motor compressor, the condenser coil, and the evaporator coil are coupled in series refrigerant flow circuit. These conduits (not shown) include a discharge line through which refrigerant normally is delivered from the compressor to the outdoor coil or the condenser, and a feed line comprising a continuously open restrictive connection through which liquified refrigerant is normally fed to the indoor coil for expansion therein. Refrigerant is withdrawn by the compressor from the evaporator through a suction line to complete the refrigerant flow circuit. Compressor 24 is selectively energized by electrical circuit means hereinafter to be more fully described and including control panel 20.

Referring again to the air rnoving means, a motor 26 of the variable speed type rotatably supports a blower wheel 27 operable to circulate air in heat exchange relation with evaporator coil 22. Blower wheel 27 is housed within a scroll structure 31 disposed adjacent a partition 32 which divides the cabinet into an evaporator coil chamber and a condenser coil chamber. The portion of cabinet 11 comprising one chamber is adapted to extend into a room or space to be air conditioned while another chamber, lying to the other side of partition 32, extends outwardly of the room, preferably through a window opening thereof. The evaporator coil chamber is subdivided by another partition 33 into a section having disposed therein the blower wheel 27 and scroll 31, and a section in which there is disposed the evaporator coil 22, The mouth portion of scroll 31 extends through partition 33 and into cooperable disposition with a sloping batlle 35 to direct air upwardly and against one face of the evaporator coil which is positioned at an angle.

The condensing coil chamber also has disposed therein motor compressor 24 and fan motor 26. A propeller-type fan 34 is rotatably supported within the chamber by motor 26 to provide for drawing outside air into the chamher over the coil 25 and for discharging the spent air outwardly from the chamber over motor compressor 24.

Disposal means for condensate dripping from evaporator coil 22 includes sloping baflle 35 disposed below the evaporator coil, and a trough 36 extending across the batfie and feeding into a conduit 37 extending through partition 32 and above a lower sump portion of base 12. Preferably fan 34 carries a conventional slinger ring (not shown), which is adapted to dip into condensate collected in the sump portion of base 12. As the fan rotates, condensate entrained by the ring is centrifuged onto a baffle plate 41 arranged to direct such condensate for flow over condenser coil 25, for subsequent evaporation therefrom.

With reference also to FIGURE 3, control circuit means for achieving capacity modulation according to the invention is arranged as shown relative to a source of A.C. energy L L The circuit for energizing motor compressor 24 includes a bellows-actuated thermostatic switch 42 disposed in series electrical circuit with L L and motor compressor 24. A sensing bulb 43 for switch 42 is positioned in the path of air caused to flow into inlet 17 of blower scroll 31. Thermostatic switch 42 is of the adjustable type and may be set to achieve cyclic operation of the motor compressor.

Also in parallel electrical circuit with the compressor, and in series with L L is fan motor 26 and its associated control circuit for modulating the speed of the fan motor, whereby to vary the cooling capacity of the air conditioner. Thermostatic switch 42 includes elements of the aforementioned associated control circuit. Consid ered in its entirety, and with reference also to both FIG- URES 4 and 5, switch 42 includes a single-pole singlethrow switch element 44 that is actuated through a levertype linkage 45 (FIGURE 3) by a vapor-pressure-type bellows 46. Selectivity of temperature operating range is provided through a rotatable cam 47 coupled with a cam arm or follower 51 arranged to vary the force on a spring (not shown) that is operable, in turn, to vary the load on the bellows 46. Cam 47 is rotatable by a manual knob 52 to the desired temperature setting.

The structure of the thermostatic switch 42 as thus far described is conventional. The present invention involves provision of means including a lever 53 actuatable by the switch linkage 45 when the temperature sensed by control bulb 43 is above the compressor cut-out setting. Lever 53 includes a set-screw S that abuts arm 59 of a vane 54 pivotally mounted at 60 and interposed between a lamp 55 and a photocell 56, such as, for example, a photoelectric device known as a photoresistor. A tension spring 62 extends between the body of control 42 and the vane 54 and maintains engagement of lever 59 against screw S. A shield 67 overlies the lamp 55 and is provided with a slotted aperture 61 that predetermines the maximum intensity of light impinging on photocell 56.

The lamp and photocell are wired into the circuit which is illustrated in FIGURE 3 and includes the variable speed fan motor 26. The circuit is so arranged that when vane 54 completely blocks off the light normally impinging upon photocell 56, fan motor 26 runs at high speed, and when vane 54 permits full passage of light to the photocell, fan motor 26 runs at low speed. Fan motor 26 is of the permanent capacitor, split-phase type, and is capable of having its speed infinitely varied between about 1100 and 550 rpm. Fan motor speed is varied between these limits in correspondence to the quantity of light permitted by vane 54 to impinge on photocell 56.

Speed control of fan motor 26 is achieved by means of a semiconductive device 38 known in the trade as a TRIAC and disposed in series circuit with L L and the main winding 29 of motor 26. A capacitor 28 is connected in series circuit with motor start winding 30, and elements 28, and 30 are connected in parallel electrical circuit with the main winding 29 of the motor and its control circuit. Firing of the TRIAC 38 is achieved by another semiconductive device 39 known in the trade as a DIAC and connected as shown in a circuit including the TRIAC 38, a pair of capacitors 40 and 48, and a resistor 49, each in series with one another while forming a circuit in parallel with motor 36 and the TRIAC. Photocell 56 is connected in parallel with capacitor 48, and functions to control the rate of attainment of firing voltage applied by DIAC 39 to TRIAC 38, and consequently the effective operating current applied to the motor winding 29.

The photoresistor or photocell 56 is connected in series electric circuit with L L capacitor 40, and resistor 49. The firing voltage for low fan speed is preset by adjusting variable resistor 49. Fan speeds between low and high are controlled by variations in resistance of the photoresistor, as provided by variations in the position of vane 54. To ensure uniform intensity of light emitted by lamp 55, it is connected directly to L on the one hand, and to L on the other hand, through resistors 50 and 58, and circuitry associated therewith as shown.

A series circuit comprised of a resistor 62 and capacitor 63 is connected in parallel with TRIAC 38 to provide for suppression of the voltage surge which is characteristic of an inductive load such as motor 26. Finally, a capacitor 64 is connected in parallel circuit with capacitors 40 and 48 and resistor 49 to provide radio frequency suppression.

In operation of the hereinabove described apparatus, line switch 63 is closed by operating a pushbutton on panel 20, and thermostat 42 is set for a desired temperature range by positioning knob 52. This will initially energize motor compressor 24 and fan motor 26, the latter at its full, or high speed. The fan motor will be operating at full speed because vane 54 will be in such position as to block light radiated by lamp 55 from impinging on photocell 56. Under this condition, TRIAC 38 operates to deliver full power to fan motor 26. As the temperature of the room is reduced, and bellows 46 has contracted to approach such position as to open switch 44, vane 54 begins to be moved, by linkage 53, to a position uncovering a portion of aperture 61. Light begins to impinge on photocell 56, thereby generating a gate signal in DIAC 39, causing TRIAC 38 to deliver reduced power to the fan motor and thereby reducing its speed. As the vane continues to move, power delivered to the motor, and hence its speed, will be decreased at a rate proportional to the quantity of light impinging on the photocell, or photoresistor, By the time switch 44 has opened, aperture 61 is fully uncovered by the vane 50 to permit full impingement of light on the photocell, with consequent low speed operation of the fan motor and deenergization of motor compressor 24.

Vane 54 .and its associated linkage 53 is so constructed and arranged as to remain in this position until such time as the cut-in temperature of thermostat 42 is attained to close switch 44 and again energize the motor compressor. Closure of switch 44 results in movement of linkage 53 to cause vane 54 again to begin to cover aperture 61. Subsequent movement of the vane to effect increased covering of the aperture reduces impingement of light on the photocell, thereby permitting delivery of increased power to the fan motor, with consequent operation at higher speed to increase the cooling capacity.

While a preferred electrical circuit has been shown for deriving a fan motor speed change signal from photoresistor 56, it will, of course, be understood that other known circuit arrangements may be used in achieving the inventive combination set forth in the appended claims and briefly described in the earlier-presented summary of the invention.

I claim:

1. In air conditioning apparatus, cooling means, means operable to energize said cooling means, a fan for moving air over said cooling means, a variable speed motor for operating said fan, and manually adjustable control means for regulating energization of said cooling means in response to temperatures of air being caused to move over the cooling means, said control means further being operable to decrease the speed of said fan motor at a rate corresponding to the rate of reduction of air temperature sensed by said control means, said control means comprising: a temperature sensing element and linkage means driven thereby and movable between predetermined limits in correspondence to sensed temperatures; switch limits in correspondence to sensed temperatures; switch means operable by said linkage means to energize said cooling means at a higher air temperature value and to deenergize said cooling means at a lower air temperature value; and means operable by said linkage means continuously to vary the speed of said fan motor in a range comprising maximum speed upon energization of said cooling means and minimum speed upon deenergization of said cooling means, said last recited means comprising a photoelectric device and circuit means associated therewith operable to modulate the fan motor speed, a lamp for directing light onto said photoelectric device, a movable vane interposed between said lamp and said photoelectric device, and means operably coupling said vane to said movable linkage means to vary the quantity of light impinging on said photoelectric device, and consequently to vary the speed of the fan motor.

2. In air conditioning apparatus, cooling means comprising a refrigerant evaporator means operable to energize said cooling means comprising a refrigerant motor compressor, a fan for moving air over said cooling means, a variable speed motor for operating said fan, and manually adjustable control means for regulating energization of said cooling means in response to temperatures of air being caused to move over the cooling means, said control means further being operable to decrease the speed of said fan motor at a rate corresponding to the rate of reduction of air temperature sensed by said control means, said control means comprising: temperature sensing means and linkage means movable thereby between predetermined limits in correspondence to temperatures sensed thereby; switch means operable by said linkage means to energize said motor compressor at a higher air temperature and to deenergize said motor compressor at a lower air temperature; and means operable by said linkage means continuously to vary the speed of said fan motor within a range comprising maximum speed upon motor compressor energization and minimum speed upon deenergization, said last recited means comprising a photoresistor and circuit controlled thereby operable to modulate the fan motor speed, means for directing light onto said photoresistor, movable vane means for varying the intensity of light impinging on said photoresistor, and meas operably coupling said vane to said movable linkage means to vary the quantity of light impinging on said photoresistor, and consequently to modulate the speed of the fan motor, in accordance with the sensed air temperature.

3. For use in an air conditioner having a refrigeration system comprising a motor compressor, a condenser, an evaporator, fan means for directing individual air streams over said condenser and evaporator, and a variable speed motor for said fan means, control means comprising: a temperature sensing element movable between predetermined limits in correspondence to temperatures of the evaporator air stream sensed thereby; switch means operable in correspondence with temperatures detected by said sensing element to energize said motor compressor at a higher evaporator air stream temperature and to deenergize said motor compressor at a lower air stream temperature; and fan speed modulating means operable in correspondence with temperatures detected by said sensing element to vary the speed of such fan motor throughout a range including higher speeds while the motor compressor is energized and a minimum speed upon motor compressor deenergization, said last recited means comprising a photoelectric device and a circuit controlled thereby and operable to modulate fan motor speed, a lamp for directing light onto said photoelectric device, a movable vane for varying the intensity of light impinging on said photoelectric device, and means operably linking said vane to said movable sensing element to vary the quantity of light impinging on said photoelectric device, and consequently modulate the speed of such fan motor, in accordance with the sensed temperaturc.

4. In air conditioning apparatus, cooling means, means operable to energize said cooling means, means operable to direct air over said cooling means, and means for varying the cooling effect of said cooling means comprising manually adjustable control means for regulating energization of said cooling means in response to temperatures of air moving over the latter, said control means further being operable continuously to modulate the air directing means to effect a decrease in air flow as the air temperature is decreased, said control means including: a temperature sensing element movable between predetermined limits in correspondence to temperatures sensed thereby; switch means operable by said sensing element to energize said cooling means at a higher air temperature and to energize said cooling means at a lower air temperature; and means operable by said sensing means to modulate the air directing means while the cooling means is energized in a range comprising higher air fiow at higher temperatures and lower air flow at lower air temperatures, said last recited means comprising a photoelectric device operable to modulate the air directing means, a lamp for directing light onto said photoelectric device, a movable vane interposed between said lamp and said photoelectric device, and means operably linking said vane to said movable temperature sensing element to vary the quantity of light impinging on said photoelectric device and consequently the rate of air flow over the cooling means.

5. In air conditioning apparatus, cooling means, means operable to direct air over said cooling means, and control means operable to modulate the air directing means, said control means including: a temperature sensing element movable between predetermined limits in correspondence to temperatures sensed thereby; and means operable by said sensing means to modulate the air directing means, and achieve higher air flow at higher air temperatures, said last recited means comprising a photoelectric device operable to modulate the air directing means in accordance with the quantity of light impinging thereon, means for directing light onto said photoelectric device, and means operable by said movable temperature sensing element to vary the quantity of light from said source impinging on said photoelectric device, and consequently to vary the rate of air flow over the cooling means.

References Cited UNITED STATES PATENTS 2,236,058 3/1941 Henney 62-180 2,770,101 11/1956 Smith 62180 3,009,332 11/ 1961 Spiegelhalter 62-180 3,034,314 5/1962 Canter 62-180 3,070,972 1/ 1963 Atchison 62180 3,276,220 10/1966 Miner 62180 3,324,672 6/1967 Sones 62-180 WILLIAM J. WYE, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Column 1, after-line 22,-, insert Column' 5", line 15, cancel "switch limits Background of temperatures,-"; line 58, "meas" the Invention in correspondence to sensed shouldread'- means Signed andsealenthis 3rd day of March 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, Attesting Officer Commissioner of Patents

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