Air conditioning control system

Abstract

A multiple zone forced air type air conditioning system is disclosed in which the amount of atmospheric air admitted to the system is governed according to sensed temperature conditions of air being circulated through the warmest zone. An atmospheric air sensing control unit responds to atmospheric air temperature and moisture levels to minimize introduction of atmospheric air to the system, notwithstanding the temperature of air being circulated through the warmest zone, when atmospheric air temperature is within a predetermined temperature range but contains more than a predetermined amount of moisture, and when atmospheric air temperatures are higher than the temperature range. The control unit enables atmospheric air to be introduced into the system according to the air temperature being circulated through the warmest zone when the atmospheric air is within the temperature range and contains less than the predetermined moisture content as well as when the air temperature is below the temperature range regardless of moisture content.

What is claimed is: 
     
       1. A control device responsive to ambient air temperature and moisture content levels comprising: a. a control unit operable between first and second control conditions;   b. an operating member for said control unit, said operating member supported for movement between first and second positions in which said control unit is in said first and second conditions, respectively;   c. relative humidity responsive means for moving said operating member and comprising an elongated humidity sensing element comprised of a material which changes length in response to changes in relative humidity of air ambient said element and supporting structure for said element;   d. air temperature responsive means cooperating with said relative humidity responsive means to prevent actuation of said operating member in response to changes in ambient air relative humidity occurring as a result of air temperature changes within a given range, said operating member being moved substantially only in response to sensed changes in moisture content of the air in said temperature range; and   e. said temperature responsive means comprising a link member movable to a first position in response to sensed air temperatuers above said range to prevent actuation of said operating member to its first position by said humidity responsive means, said link member movable to a second position in response to sensed air temperatures below said range to prevent actuation of said operating member to its second position by said humidity responsive means.   
     
     
       2. A control as claimed in claim 1 wherein said link member defines first and second spaced abutments, said first abutment engaging said operating member and maintaining said operating member in its first position when atmospheric air temperature is reduced to the lowest temperature of said temperature range, said second abutment engageable with said operating member for maintaining said operating member in its second position when atmospheric air temperature is increased to the highest temperature of said range. 
     
     
       3. A control as claimed in claim 2 wherein said supporting structure for said element comprises a part for connecting said element to said operating member, said element effective to change length and move said operating member between its first and second positions when said abutments are spaced from said operating member in its first and second positions, respectively. 
     
     
       4. The device claimed in claim 3 wherein said element support structure further comprises a part for connecting said element to said temperature responsive means, said temperature responsive means effective to move said element in response to sensed atmospheric air temperature changes within said range, incremental changes in length of said element due to temperature effects on sensed relative humidity are substantially ineffective to move said operating member. 
     
     
       5. A control mechanism responsive to changes in air temperature and moisture conditions comprising: a. a control member actuable between first and second positions;   b. a moisture sensing mechanism comprising: i. a humidity sensing element which changes dimension as the relative humidity of air ambient the element changes;   ii. temperature responsive means cooperating with said humidity sensing element to move said element in response to sensed temperature changes within a first range so that said element effectively changes dimension substantially only in response to changes in ambient air moisture content;   iii. structure interconnecting said element and said control member for effecting movement of said control member as said element effectively changes dimension;   iv. said humidity sensing element and said temperature responsive means cooperating to operate said control member to one of said positions in response to detection of ambient air within said temperature range having less than a first predetermined moisture content and to operate said control member to said other position in response to detection of ambient air within said temperature range having greater than said predetermined moisture content; and,     c. linkage means interconnecting said temperature responsive means and said control member for operating said control member to one of said positions when ambient air temperatures increase beyond said temperature range irrespective of the air moisture content, and operating said control member to said other position when ambient air temperatures decrease below said temperature range irrespective of the air moisture content.   
     
     
       6. The mechanism claim in claim 5 wherein said temperature responsive means further comprises thermostatic actuator means and lever means engaged by said actuator means; said lever means comprising a lever member having first and second end portions, pivot structure supporting said lever member for rotation about said first end portion, a part engageable with said thermostatic actuator means between said end portions and structure for connecting said second lever end portion to said linkage means. 
     
     
       7. The mechanism claimed in claim 6 wherein said linkage means comprises an elongated body member extending from said lever means, and first and second spaced abutments defined on said body member, said body member movable in the directions of its extent in response to movement of said lever means, said first abutment effective to cause operation of said control member to said first position when said body member moves in one direction and said second abutment effective to cause operation of said control member to said second position when said body member moves in the opposite direction. 
     
     
       8. The mechanism claimed in claim 7 further including a pivotally supported operating member having a first position extending into engagement with said control member and a second portion extending between said first and second abutments, said operating member pivotally movable with respect to said operating member to move said operating member between said positions. 
     
     
       9. The mechanism claimed in claim 8 further including first element support means for connecting said humidity sensing element to said second end of said lever member and second element support means for connecting said humidity responsive element to said second portion of said operating member. .Iadd. 10. A control unit comprising: (a) a support housing;   (b) a control switch unit support by said support housing and operable between first and second conditions;   (c) a switch operating member supported by said housing for movement relative to said switch unit, said operating member effective to move and change the condition of said switch unit;   (d) a humidity responsive mechanism effective to move said switch operating member in response to sensed changes in humidity;   (e) a temperature responsive mechanism for effecting movement of said operating member in response to sensed changes in temperature;   (f) said humidity responsive mechanism comprising a humidity sensitive element whose length tends to change in response to changes in humidity, said element disposed between said temperature responsive mechanism and said switch operating lever to exert actuating force on said operating member which varies as a function of sensed temperature and humidity; and,   (g) said temperature responsive mechanism comprising an actuator member for transmitting force to said switch operating member from said temperature responsive mechanism to maintain said control switch unit in one of said conditions when sensed humidity levels are such that said humidity sensitive element is ineffective to maintain said switch unit in said one condition. .Iaddend. .Iadd. 11. The control unit claimed in claim 10 wherein said humidity sensitive element comprises an elongated element for transmitting tensile forces between said operating member and said temperature responsive mechanism, said element tending to elongate in response to sensed increases in humidity, said actuator member extending generally parallel to said element and having a lost motion connection with said operating member. .Iaddend..Iadd. 12. The control claimed in claim 10 further including manually operable means for positioning said operating member to maintain said control switch unit in said one condition regardless of sensed humidity and temperature. .Iaddend..Iadd. 13. The control unit claimed in claim 10 wherein said actuator member is supported for lost motion with respect to one of said temperature responsive mechanism or switch operating member so that said humidity sensitive element is effective to move said switch operating member while said actuator member undergoes lost motion. .Iaddend. .Iadd. 14. A control unit sensitive to changes in sensed air temperature and humidity comprising:   (a) a control switch unit operable between first and second conditions;   (b) an operating member movable relative to said switch unit to operate said switch unit between said conditions; and,   (c) an actuator system for positioning said operating member in relation to sensed temperature and humidity comprising: (i) a first lever pivotally movable relative to said operating member;   (ii) a thermally responsive power element for moving said first lever;   (iii) a second lever pivoted to said first lever;   (iv) an elongated humidity responsive element extending between said second lever and said operating member, the length of said element changing in response to changes in humidity so that said operating member can be repositioned in response to sensed changes in humidity and temperature; and,     (v) a link member connected for lost motion engagement between said actuator system and said operating member;   said operating member being positionable by said link member irrespective of said humidity responsive element under predetermined sensed conditions. .Iaddend. .Iadd. 15. A control comprising:   (a) a support housing;   (b) a control switch unit supported by said housing, said control switch unit operable between first and second conditions;   (c) an operating member supported by said housing and movable to alter the condition of said control switch unit;   (d) humidity responsive actuator means for moving said operating member in response to sensed changes in humidity, said humidity responsive actuator means comprising a lever supported for pivotal movement relative to said housing and an elongated humidity responsive element extending between said lever and said operating member;   (e) temperature responsive actuator means for moving said operating member in response to sensed temperature changes, said temperature responsive actuator means comprising: (i) a second lever pivotally supported by said housing;   (ii) a thermally responsive power element for pivoting said second lever relative to said housing in response to temperature changes;   (iii) structure for pivoting said first lever to said second lever so that said element is effective to transmit force from said temperature responsive actuator to said operating member; and,   (iv) a link member connected for lost motion between said operating member and a location in the vicinity of the pivot structure between said first and second levers, said link member effective to move said operating member to maintain said switch unit in one condition when temperature falls below a predetermined level substantially independently from sensed humidity. .Iaddend.