US3747671A

US3747671A - Air circulation control system

Info

Publication number: US3747671A
Application number: US00194139A
Authority: US
Inventors: L Schwitzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-11-01
Filing date: 1971-11-01
Publication date: 1973-07-24
Anticipated expiration: 1990-07-24

Abstract

Automatic control to maintain the temperature of air within an enclosure within a predetermined temperature range and of a generally uniform temperature from floor level to ceiling level comprises a heating and cooling source connected by duct means through control valve means to ceiling and floor vent means in the enclosure. A thermostat means in the enclosure controls the heating and cooling source as well as the control valve means so that when heating of the enclosure is required the control valve means is moved to a first position wherein heated air enters the enclosure through the floor vent means and is exhausted from the enclosure through a floor vent means to be returned to the heating and cooling source for recycling and whereby when the enclosure temperature must be lowered the control valve means is moved to a second position whereby cool air enters the enclosure through one ceiling vent means and is exhausted from the enclosure through another ceiling vent means to be returned to the cooling source.

Description

United States Patent [1 1 Schwitzer, Ill

[ 11 July 24, 1973 Filed:

AIR CIRCULATION CONTROL SYSTEM Inventor: Louis n. Schwitzer, n1, RR. 11,

Box 203 A, Bloomington, 1nd. a

Field r Search Nov. 1, 1971 Appl. N0.: 194,139

U.S. Cl 165/26, 165/27, 98/33 R Int. Cl..., F28! 27/02 References Cited UNITED STATES PATENTS Bradshaw et a1.

Dean, Jr. 165/50 X Parks Marshall Ostrander 165/26 X Primary Examiner-Manuel A. Antonakas A ttorney Carl't6iil lill, Lewis" Tfsteadmaii c t an. R

[57] ABSTRACT Automatic control to maintain the temperature of air within an enclosure within a predetermined temperature range and of a generally uniform temperature from floor level to ceiling level comprises a heating and cooling source connected by duct means through control valve means to ceiling and floor vent means in the enclosure. A thermostat means in the enclosure controls the heating and cooling source as well as the control valve means so that when heating of the enclosure is required the control valve means ismoved to a first position wherein heated air enters the enclosure through the floor vent means and is exhausted from the enclosure through a floor vent means to be returned to the heating and cooling source for recycling and whereby when the enclosure temperature must be lowered the control valve means is moved to a second position whereby cool air enters the enclosure through one ceiling vent means and is exhausted from the enclosure through another ceiling vent means to be returned to the cooling source.

10 Claims, 3 Drawing Figures AIR CIRCULATION CONTROL SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to a heating, cooling and ventilation system for an enclosure and more specifically contemplates an air circulation control system whereby a control valve means in a duct system between a heating and cooling source and an enclosure having ceiling and floor inlet and outlet means serves to maintain the temperature in the enclosure within a predetermined temperature range and generally uniform from floor to ceiling.

2. Prior Art As is well known, the usual hot air heating systems such as are employed in homes and business establishments have ducts extending from the source of heat and opening through registers or vents leading into the room or enclosure. In such heating systems it is usual to have the registers or vent means either in the floor or in the baseboard, and in any event at a lower portion of the room and to'have cold air return means in another, generally opposite lower portion of the room so that the heated air entering into the room or enclosure through the register will rise by convection until it loses its heat and then will fall to be exhausted through the cold air return means. Such a system operates admirably in hot air heating. However, in more recent years, it has become usual to employ the same ducts for the circulation of cool air for so-called air cooling or air conditioning. In those cases the system does not operate as effectively since cold air does not rise and a zone near the floor of the room to be cooled remains cold whereas upper portions of that room may remain warm. In same cases where air conditioning is provided. for an enclosure the cool air inlet is provided in the upper part of the room or enclosure and the air outlet remains in the lower part to thereby leave cold air near the floor with hot air trapped near the ceiling.

In addition the prior art also has no simple and yet efficient system of control for both hot and cold air to maintain uniformity of room temperatures within a relatively narrow predetermined temperature range so that differences between the upper and lower portions of a room or enclosure may vary and be noticeable to occupants of the room.

Furthermore, to applicants knowledge the prior art is lacking in a simple and effective means of automatically controlling the temperature in a room with a narrow predetermined temperature range so that comfort of the occupant is maximized.

SUMMARY OF THE INVENTION The disadvantages of the prior art are overcome by my invention in an air circulation control system which automatically maintains the room or enclosure temperature within a narrow predetermined range and at a uniform temperature from floor to ceiling by means of a control valve means including a first and second valve system of ducts between a heating and cooling source and the upper and lower vent means in the enclosure when the temperature of the room is such as to call for hot air, the controlvalve means is automatically moved to a first position and heated air forced through portions of the duct system enters the enclosure ata lower inlet vent means and is exhausted from the enclosure by a lower or floor outlet vent means and returned, via

the duct system to the heating source for recycling. When the temperature exceeds the predetermined degree or temperature range the control valve means moves to a second position whereby cooled air from a cooling source in the duct system is forced into the enclosure through an upper or ceiling inlet means and is exhausted from the enclosure through an upper outlet vent means and recirculated through the duct system to the cooling source.

In one preferred embodiment the air circulation control system includes a first valve means at the outlet side of the heating and cooling source, a first heating duct means for moving hot air from the first valve means to the lower hot air inlet vent in an enclosure, a second heating duct means for exhausting the air from the enclosure through a lower air outlet means and transmitting it to and through a second control valve means from which it is channeled back to the inlet side of the heating and cooling means for recycling. A control means detecting the temperature in the enclosure and transmitting required signals for heating or cooling of the air to a preselected temperature are connected with the control valve means as well as the heating and cooling source. Thus; when these controls indicate that cooling is required an appropriate signal to the heating and cooling means and the first and second valve means causes the cooling means to be activated and the first and second valve means to rotate to channel cooled air from the first valve means through a first cooling duct means to an inlet vent at an upper level of the enclosure. Cooled air which has served its function is drawn off through an outlet in an upper portion of the enclosure spaced from the inlet and the air moves via a second cooled air duct to and through the second valve means back to the inlet side of the cooling means.

In a second embodiment of the invention herein especially adapted to be used on what is known as a self contained heating and cooling arrangement, a first heating duct means from the heating unit transmits air through a lower inlet opening into an enclosure and a second heating duct means transmits the used heated air through an outlet at a lower position in the enclosure and back to the inlet side of the heating means. A similar arrangement of first and second cooling ducts connected to a source of cooled air supplies and exhausts cooled air from the upper portion of the enclosure.

In each arrangement a third valve means may be pro vided in the duct system to exhaust the spent hot or cold air and supply a source of fresh air to the system.

While the invention has been described conceptually in terms of an enclosure or room, it will be understood that a plurality of rooms and enclosures are contemplated with the system herein. Accordingly, a plurality of plenum chambers may be provided in the duct work system whereby a plurality of rooms or enclosures may be heated or cooled off of a central distribution duct work system. Furthermore, each room or enclosure may be on a separate duct work system whereby the site sides of a central portion having an axle means therein. A pivotally mounted closure member adjacent the openings is movable about the axle means between a first position efficiently closing the openings in the second dividing means and a second position closing the previously opened opening in the first dividing means and opening the previously closed opening in the second dividing means. Advantageously, the dividing means may be formed by two pieces each of which is bent at its intermediate portion approximately ninety degrees to form an apex. The portions are positioned in the housing with their apexes spaced from each other by the width of the axle means for the closure member. The closure member includes two portions on opposite sides of the axle that extends over the opening means.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure and in which:

FIG. 1 is a diagrammatic representation of one embodiment of an air circulation control system according to the invention herein;

FIG. 2 is a cross sectional perspective view of an embodiment of a control valve means according to the invention; and,

FIG. 3 is a schematic representation of another system according to the invention herein.

DESCRIPTION OF A PREFERRED EMBODIMENT The air circulation control system invention as schematically depicted in FIG. 1 applied to an enclosure comprises a heating and cooling source positioned at a point remote from the enclosure 10 and connected thereto by a system of ducts, valves and plenum chambers. The heating and cooling source 20 may include a heating means schematically depicted at 22 and a cooling means schematically depicted at 24 which are of a size and design to provide adequate heating and cooling of air passing from an inlet side 26, past the heating or cooling means 22, 24 and out of the outlet side 28 into a valve means 30 as shown in FIG. 2.

A closure plate member 34 is pivotable about a central axis 36 in response to appropriate thermostatic controls to deflect cold air as represented by the arrow C into a cold air duct means 50 which in turn outlets into the enclosure or room 10 through the register or opening 52. After the cooled air of greater density than the air in the room has fallen by convection and has performed its function, it rises and is exhausted from the room 10 through the register means 62 and passes by way of duct means 60 to a second valve means 70 by which it is directed toward the inlet 26 of the heating and cooling means 20. The second valve means 70 may A third valve means 80 positioned between the second valve means and the cooling and heating means 20 includes a valve member 82 which pivots about an axis 83 between a position as shown in solid lines wherein the cycled air is directed from the second valve means directly to the heating and cooling means 20 and a second position indicated in dotted lines wherein the cycled air is exhausted from the system through a duct 86 and fresh air is introduced into the system by means of a duct 88. The third valve means is positioned in a duct 66 extending from the second valve means 70 to the inlet 26.

When the temperature of the enclosure 10 is such that a supply of heated air is required to raise the room temperature to a preselected value, the air circulation control system according to the invention herein may be made to automatically respond thereto and supply the heated air necessary to meet the preselected level. The detection of the enclosure temperature level may be made by a thermostat means 12 located in the room and connected by wiring means 13 and 14 to the cooling source 20 and in the valve means 30, 70, 80 as will be known and understood by those skilled in the art. Each of the valve means 30, 70 and 80 preferably has connected thereto a power means for operating the valve closure means 34, 74 and 83 respectively, so that automatic operation thereof may be effected by the thermostat control means 12.

When the thermostat control means 12 senses a condition which requires a change from cooled air to heated air a suitable signal is relayed by the wire means 13 and 14 to the heating and cooling source means 20 as well as the valve means 30 and 70 so that the cooling source 24 is inactivated and the heating means 22 is activated. In addition, the valve closure plate means 34 and 74 in the first and second valve means respectively, shift the position shown in solid lines to a position shown in dotted lines whereby the heated air being forced up through the system by the air movement means 21 now passes from the outlet 28 into a first heating duct means 90 through which it is delivered through a register opening 92 into the enclosure 10. In the room 10 the heated air serves its function in raising the air temperature and, after serving this function is drawn through a register 94 into a second heating duct means 96 through which it passes to and through the second valve means 70 and is controlled by the third valve means 80 to either be exhausted through the duct 86 or returned directly through the duct 66 to the heating source 20 for recycling. Valve means 30 and 70 respond to thermostat 12, while valve means 80 is controlled thermostatically during the heating cycle, and manually controlled during the cooling and summer fan cycles.

While the invention has been described in terms of a single enclosure 10, it will be understood that in most cases a plurality of rooms or enclosures 10 will be served by the system and hence, in these situations, I have provided a plurality of plenum chambers to facilitate distribution to a plurality of rooms or enclosures. Thus, a first plenum chamber 54 in the duct means 50 allows distribution to other enclosures not shown, through duct means 55 and 56. Similarly, a second plenum means 63. in the second duct means 60 may provide for connection of return duct means from other enclosures such as shown, for example, at and 65. A third plenum chamber means 91 in the duct means 90 serves a similar function by allowing connections to other enclosures by means such as illustrated at 93. Again, in the return duct means 96 a fourth plenum chamber 97 allows accommodation of the system to a plurality of enclosures by means such as shown at 98.

By means of the air circulation control system according to the invention an efficient, and accurate flow of air may be obtained.

Referring to FIG. 2 there'is shown an enlarged perspective view of the first valve means 130 of FIG. 3 with the closest end of the housing removed. A housing 131 has opposite ends which receive the axle 136 in bearing relationship. The axle 136 has attached thereto on opposite sides flaps 134a and 134b which serve to form the butterfly valve indicated at l34. The housing 131 has a first dividing means'137 extending diagonally thereof and a second dividing means 138 positioned on the opposite diagonal so as to intersect the first dividing means. Each of the dividing means 137, 138 has a first portion 137a, 138a on one side of the area of intersection of the dividing means and a second portion 137b, 138b on an opposite side of the area of intersection. Each of the portions 137a, 137b, 138a, 138k has an

opening

1370, 137d, 1380, 138d respectively, which is of smaller size then the respective portion so that it can be effectively closed. To provide effective sealing each of the openings may be surrounded with a sealing material generally indicated at 141 which will be positioned on the side against which the closure means will be seated. The openings may be of a size and shape to ac commodate the desired flow therethrough.

As illustrated the housing 131 is rectangular in cross section and has openings on each of the four sides. Thus, opening 142 is on the bottom, opening 143 is on one side, opening 144 is on the top and opening 145 is on the other side. In

valves

30 and 70 opening 144 is omitted. A motive means 146 provides the power to move the control member 134 from a first position illustrated where the closure member 134 covers the

opening

1370 and 137d to a second position wherein it covers the opening 1380 and 138d. With the closure member 134 in the first position it may be thus seen from the arrows A and B that separate and adjacent paths may be provided through the control valve means 130. Movement of the closure member 134 to the second position will be seen to direct the flow of air coming upward through the opening 142 out through the opening 137d and the opening 145. Similarly, the flow of air as represented by the arrow B will be diverted from the opening 145 to the opening 143.

Advantageously the dividing means 137, 138 of the control valve means'130 may be formed of two pieces each of which is bent at its intermediate portion approximately 90 to form an apex. Thus, the first piece would-include the first portion 137a of the dividing means 137 and the second portion 1381: of the dividing means 138 while the second bent piece would include the first portion 138a and the second portion 137b. When positioned with their. edges in the corners adjacent one side, the bent portions have their apexes spaced from each other by the width of the axle means 136. I have found this construction of the control valve member to be very efficient and yet very economical in construction.

Referring to FIG. 3 there may be seen an example of a further embodiment of my invention as applied to an enclosure 110. In this embodiment, known as the selfcontained version, a heating means 122 is positioned adjacent the enclosure and is connected thereto by duct means 180 transmitting hot air from the heat source 122 to an inlet 182 in the enclosure 110. Similarly, a' duct system 184 receives exhaust hot air through an inlet 185 and transmits it through an inlet side 186 of the heating unit 122.

At a location remote from the heating unit 122 a cooling unit 124 is positioned so that cooled air is blown into the enclosure 110 through a duct means while cooled air which has served. its function is withdrawn from the enclosure 110 through a duct means and returned to an inlet side of the cooling unit 124. It may be here seen where a control valve member 130 is positioned atop the cooling means 124.

In this case the control valve means 130 functions to provide an alternative closed circulation system wherein cooled air is circulated from the cooling means 124 through the enclosure 110 and returned or, with the valve means 130 in a position as indicated by dotted lines, the cooling means 124 draws fresh air indicated by a dotted line in through the opening 143 to be cooled and cycled through the system to the point where it returns to the control valve means 130 at which point it is exhausted through the top opening 144 as indicated by the dotted lines. It will be understood by those skilled in the artthat suitable automatic control means may be provided whereby a preselected temperature may be maintained in the enclosure 110. Furthermore, although a single enclosure 110 has been illustrated it will be understood that a plurality of enclosures are contemplated and may be provided for by suitable connecting means such as plenum chambers.

In both the system of FIG. 1 and FIG. 3 a suitable air filter means such as an electrostatic filter means may be provided. Thus, as shown in FIG. 1, the electrostatic filter means 49 as schematically designated is positioned between the hot and cold air source 20 and the first control valve means 30. In FIG. 3 a similar filter means 148 is shown on the outlet side of the hot air means 122 and a filter means 149 is shown in combinaion with the cooling means124. Also in the system of FIG. 1 a known type of power humidifier99 is included in duct 90; and in the system of FIG. 3 a power humidifier 187 is included in duct 180.

From the foregoing description of my invention it may be seen that the temperature of air within an enclosure may be maintained within a predetermined temperature range and generally uniform from floor level to ceiling level by an automatic control means applied to either a split arrangement as shown in FIG. 1 or a self-contained arrangement as shown in FIG. 3. Of course, the sizes of the valve means 30, 70, 80 and 130 will vary with the size and location of the furnace. The motor may be the same. In actual operation, the power means for the valve such as shown at 146 in FIG. 2 may be wired to change with the operation of the air condi tioning unit or the heating means so that the valve will automatically change as one unit goes off and another comes on. An example of a motive means which may be used with my invention is model 25B manufactured by the Ramcon Corporation of Elgin, Illinois 60120.

The third valve means 80 as shown in FIG. 1 may have a similar arrangementand mode of operation with v the exception that the dividing means 84, 85 are changed by 45 in the housing so that they generally bisect the opposite sides of the housing and the openings 80a and 80b are arranged on one side of the vertical dividing means 84 so that when the closure means 83 is in a position as shown in solid lines the valve means effectively bypasses the air from the second valve means 76 to the conduit 66 and the heating and cooling means 20. When the closure member 83 is moved to the position indicated in dotted lines to close the openings in the dividing means 85, the returning air is forced out of the duct 86. With the return air circulation thus cut off air is drawn in through the duct 88 and cycled through the system. Each of the

duct members

86 and 88 may have one way valve 86a, 88a therein.

Although minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.

I claim:

1. An air circulation control system for an enclosure, said enclosure having a floor means and a ceiling means with wall means extending generally around and between said floor and ceiling means, said enclosure having a heated air inlet and outlet means in a lower portion of said enclosure and a cooled air inlet and outlet means in an upper portion of said enclosure, a source of heated air having an inlet and an outlet means, said heated air source outlet means being in communication with said enclosure heated air inlet by means of a first heated air duct means, a second heated air duct means extending from said enclosure heated air outlet to said heated air source inlet whereby said enclosure may be supplied with heated air, a cool air supply means having an inlet and an outlet, said supply outlet communicating through a first cooled air duct with said cooled air enclosure inlet, a second cooled air duct means exhausting said cooled air through said enclosure outlet and transmitting it to said cooled air inlet whereby effective circulation of said cooled air through said inlet is provided, and control valve means effective to selectively circulate heated air through the heated air inlet and outlet means in the lower portion of the enclosure and cooled air through the cooled air inlet and outlet means in the upper portion of said enclosure.

2. An air circulation control system according to claim 1 wherein said control valve means is movable between a first position wherein said cooled air is cycled through said first and second cooling duct means and a second position wherein said heated air is cycled through said first and second heating duct means.

3. An air circulation control system according to claim 2 wherein said system further includes a second control valve means positioned between said second cooled air duct means and said second heated air duct means so that air returning to said heating or cooling source must flow therethrough, said second control valve means having a valve member movable between a first position wherein said cooled air returning in said second cooled air duct means may pass into said'cooled air source and a second position wherein said heated air returning through said second heated air duct means may return to said heated'air source.

4. An air circulation control system according to claim 2 wherein said control valve means includes a double seated butterfly valve, said valve being driven by motor means, said motor means being controlled by a thermostat means responsive to air temperatures in the enclosure whereby alternate operation of said heating or cooling source and said valve means may be automatically controlled.

5. An air circulation control system according to claim 1 wherein said first and second cooling and heating duct means include plenum chamber means whereby said system may be extended to include a plurality of enclosures.

6. An air circulation control system for an enclosure, said enclosure having a floor means and a ceiling means with wall means extending generally around and between said floor and ceiling means, said enclosure having a heated air inlet and outlet means in a lower portion of said enclosure and a cooled air inlet and outlet means in an upper portion of said enclosure, a source of heated air having an inlet and an outlet means, said heated air source outlet means being in communication with said enclosure heated air inlet by means of a first heated air duct means, a second heated air duct means extending from said enclosure heated air outlet to said heated air source inlet whereby said enclosure may be supplied with heated air, a cool air supply means having an inlet and an outlet, said supply outlet communicating through a first cooled air duct with said cooled air enclosure inlet, a second cooled air duct with said cooled air enclosure inlet, a second cooled air duct means exhausting said cooled air through said enclosure outlet and transmitting it to said cooled air inlet whereby effective circulation of said cooled air through said inlet is provided, a first control valve means movable between a first position wherein said cooled air is cycled through said first and second cooling duct means and a second position wherein said heated air is cycled through said first and second heating duct means, a second control valve means positioned between said second cooled air duct means and said second heated air duct means so that air returning to said heating or cooling source must flow therethrough, said second control valve means movable between a first position wherein said cooled air returning in said second cooled air duct means may pass into said cooled air source and a second position wherein said heated air returning through said second heated air duct means may return to said heated air source, and a third control valve means positioned between said second control valve means in said source of heated and cooled air, and said third valve means movable between a position wherein said air passing through said second control valve means may flow directly to said source of cooled or heated air and a second position wherein said air passing through said second control valve means is exhausted from said system and fresh air may be drawn into said system.

7. An air circulation control system for an enclosure, said enclosure having a floor means and a ceiling means with wall means extending generally around and between said floor and ceiling means, said enclosure having a heated air inlet and outlet means in a lower portion of said enclosure and a cooled air inlet and outlet means in an upper portion of said enclosure, a source of heated air having an inlet and an outlet means, said heated air source outlet means being in communication with said enclosure heated air inlet by means of a first heated air duct means, a second heated air duct means extending from said enclosure heated air outlet to said heated air source inlet whereby said enclosure may be supplied with heated air, a cool air supply means having an inlet and an outlet, said supply outlet communicating through a first cooled air duct with said cooled air enclosure inlet, a second cooled air duct means exhausting said cooled air through said enclosure outlet and transmitting it to said cooled air inlet whereby effective circulation of said cooled air through said inlet is provided, a control valve means movable between a first position wherein said cooled air is cycled through said first and second cooling duct means and a second position wherein said heated air is cycled through said first apd second heated duct means, said control valve means including a double seated butterfly valve, a motor driving said valve, a thermostat controlling said motor, and a housing having first and second dividing means intersecting each other at their central portion and each having a pair of openings on opposite sides of the central portion, a pivotally mounted closure member having closure pieces on opposite sides of said axis and movable about said axis "between a first position effectively closing the openings in said second dividing means and opening the openings in said first dividing means and a second position closing the previously opened openings in said first dividing means and opening the previously closed openings in the, second dividing means.

8., An air circulation control system according to claim 7 wherein said first and second dividing means is formed of two integral pieces, each of said pieces being bent at a central portion approximately ninety degrees to form an apex, said portions being positioned in said housing with their apexes spaced from each other a distance to allow said closuremernber to move therebetween between said first and second positions.

9. An air circulation system according to claim 8 wherein said closure member includes an axle means extending through said central portion, said housing having end portions, said axle extending through said housing end portions, at least one end of said axle engaging a motor means whereby said closure member may be moved between said first and second positions by said motor means.

10. An air circulation control system according to claim 9 wherein said enclosure includes a thermostatic control means, said thermostatic control means being operable to activate said cooled air means when the temperature in said enclosure rises above a preselected temperature and being operable to operate said heated air source means when the temperature in said enclosure falls below a preselected temperature, said control valve means being wired to said cooling and heating means whereby activation of said'cooling means moves said closure member to said first position and activation of said heating means moves said closure member to said second position.

Claims

3. An air circulation control system according to claim 2 wherein said system further includes a second control valve means positioned between said second cooled air duct means and said second heated air duct means so that air returning to said heating or cooling source must flow therethrough, said second control valve means having a valve member movable between a first position wherein said cooled air returning in said second cooled air duct means may pass into said cooled air source and a second position wherein said heated air returning through said second heated air duct means may return to said heated air source.

7. An air circulation control system for an enclosure, said enclosure having a floor means and a ceiling means with wall means extending generally around and between said floor and ceiling means, said enclosure having a heated air inlet and outlet means in a lower portion of said enclosure and a cooled air inlet and outlet means in an upper portion of said enclosure, a source of heated air having an inlet and an outlet means, said heated air source outlet means being in communication with said enclosure heated air inlet by means of a first heated air duct means, a second heated air duct means extending from said enclosure heated air outlet to said heated air source inlet whereby said enclosure may be supplied with heated air, a cool air supply means having an inlet and an outlet, said supply outlet communicating through a first cooled air duct with said cooled air enclosure inlet, a second cooled air duct means exhausting said cooled air through said enclosure outlet and transmitting it to said cooled air inlet whereby effective circulation of said cooled air through said inlet is provided, a control valve means movable between a first position wherein said cooled air is cycled through said first and second cooling duct means and a second position wherein said heated air is cycled through said first and second heated duct means, said control valve means including a double seated butterfly valve, a motor driving said valve, a thermostat controlling said motor, and a housing having first and second dividing means intersecting each other at their central portion and each having a pair of openings on opposite sides of the central portion, a pivotally mounted closure member having closure pieces on opposite sides of said axis and movable about said axis between a first position effectively closing the openings in said second dividing means and opening the openings in said first dividing means and a second position closing the previously opened openings in said first dividing means and opening the previously closed openings in the second dividing means.

8. An air circulation control system according to claim 7 wherein said first and second dividing means is formed of two integral pieces, each of said pieces being bent at a central portion approximately ninety degrees to form an apex, said portions being positioned in said housing with their apexes spaced from each other a distance to allow said closure member to move therebetween between said first and second positions.

10. An air circulation control system according to claim 9 wherein said enclosure includes a thermostatic control means, said thermostatic control means being operable to activate said cooled air means when the temperature in said enclosure rises above a preselected temperature and being operable to operate said heated air source means when the temperature in said enclosure falls below a preselected temperature, said control valve means being wired to said cooling and heating means whereby activation of said cooling means moves said closure member to said first position and activaTion of said heating means moves said closure member to said second position.