US3762182A

US3762182A - Fresh air feature for room air conditioner

Info

Publication number: US3762182A
Application number: US00283749A
Authority: US
Inventors: J Loos; E Wark
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1972-08-25
Filing date: 1972-08-25
Publication date: 1973-10-02
Anticipated expiration: 1990-10-02

Abstract

An integrally hinged folding panel door assembly pivotally secured to a partition wall of a room air conditioner so as to be biased in a first folded position operative for closing a fresh air inlet communicating with the inlet orifice of the evaporator blower wheel scroll housing by means of the evaporator plenum chamber. The folding panel door assembly when actuated to an overcenter fresh air open position being operative to block-off a portion of the evaporator surface to increase the negative pressure differential in the evaporator planum chamber to induce an increased flow of make-up or fresh air being drawn into the evaporator scroll housing inlet orifice.

Description

United States Pate? Loos et al. 1 1 Del. 2, 1973 [541 FRESH AIR FEATURE FOR ROOM AIR 3,305,162 2/1967 Hall 417/84 CONDITIONER 3,643,461 2/1972 Jacobs 62/427 Primary ExaminerWilliam .I. Wye Alt0rneyWilliam S. Pettigrew et al.

[57] ABSTRACT An integrally hinged folding panel door assembly pivotally secured to a partition wall of a room air conditioner so as to be biased in a first folded position operative for closing a fresh air inlet communicating with the inlet orifice of the evaporator blower wheel scroll housing by means of the evaporator plenum chamber. The folding panel door assembly when actuated to an overcenter fresh air open position being operative to blockoff a portion of the evaporator surface to increase the negative pressure differential in the evaporator planum chamber to induce an increased flow of make-up or fresh air being drawn into the evaporator scroll housing inlet orifice.

3 Claims, 6 Drawing Figures PATENTEBIIBT 2 m SHEET 1 [IF km" m FRESH AIR FEATURE FOR ROOM AIR CONDITIONER This invention relates to a fresh air folding panel door assembly particularly adapted for use in a room air conditioner.

Various damper arrangements have been used to allow the selective entrance of make-up fresh air for mixture with recirculated room air in room air conditioners as exemplified by U.S. Pat. No. 3,305,162 issued Feb. 21, 1967 and assigned to the same assignee as the instant application.

It is an object of the present invention to provide a folding panel door assembly for a room air conditioner including hingedly connected cover and baffle panels for a room air conditioner having an inwardly canted fresh air opening located in a partition wall coextensive with a side wall of the evaporator blower scroll housing, whereby the folding door assembly is biased in one direction about hinge means into a first position to close the fresh air opening spaced a defined distance from the scroll air inlet orifice. Actuating means are provided for overcenter flexing of the panels to a second open position being operative to block-off a substantial portion of the flow of recirculated room air passing through the evaporator section thereby increasing the negative pressure differential in the evaporator chamber so as to induce increased flow of fresh or make-up air into the evaporator scroll housing.

This and other objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the invention is clearly shown.

In the drawings:

FIG. 1 is a top plan view of a room air conditioner having a fresh air folding door arrangement according to the invention;

FIG. 2 is a vertical section taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary horizontal sectional view taken along the line 3-3 of FIG. 2 with the cover panel in a closed position;

FIG. 4 is a view similar to FIG. 3 but illustrating the cover in an open position to permit the entrance of fresh air;

FIG. 5 is a fragmentary enlarged sectional view of one of the hinge sections;

FIG. 6 is a vertical sectional view taken along the line 6-6 of FIG. I.

Referring now to the drawings and more particularly to FIG. 1, there is shown a window air conditioner unit having a weather casing 20, indicated in phantom lines, enclosing a sealed motor compressor unit 22, a support bracket 24 for a fan motor 25 having a propeller fan 26 mounted on its shaft 27 which draws in outside air through suitable side louvers 28 and 29 for movement through a condenser 30 and discharge to the atmosphere by means of louvers 31 at the back of the casing 20.

An intrically formed transverse bulkhead partition, indicated generally at 34, extends across the casing 20 to divide the interior of the air conditioning unit into an inner evaporator compartment 36 and the outer compartment 38 in communication with the outside air. The bulkhead 34 includes

vertical wall sections

39 and 40 and top wall section 41. Spaced below the top wall 41 is a horizontal shelf 42 seen in FIG. 2 which together with the walls 43, 44 and intermediate wall 45 define an upper room air discharge duct 46 having a conditioned air outlet 48 extending across the front of the unit.

An evaporator 50 is located in front of a bellmouth inlet orifice 53 located in one side wall 54 of a blower scroll housing 52 including a blower wheel 51 mounted for rotation within the scroll housing which is on the inner end of a shaft 27 so as to be driven by motor 25. Air discharged radially from the blower wheel 51 will cause routing of the high velocity flowing air to be directed in a counterclockwise direction through the widening spiral passageway of the blower scroll and through the exhaust opening 56 into duct 46.

The partition wall portion 40 is provided with a rectangular first opening 60 surrounded by a gasket 61 of suitable rubber-like material. The opening 60 communicates with the outer housing compartment 38 to which stale or contaminated air may be removed from the room and exhausted into the compartment 38 from whence it is subsequently discharged into the atmosphere through louvers 32. A flapper door or damper 62 for the opening 60 is shown adapted to close the exhaust air outlet opening to in a manner such as disclosed in U.S. Pat. No. 3,305,162, issued Feb. 21, 1967 to W. B. Hall, Jr., the disclosure of which is incorporated by reference herein. The door 62 biased closed by a mousetrap spring 64 has bracket means including a flange extension 74 extending outwardly at an angle over the edge of the door containing a plastic eyelet 76. A cord or cable 78 has one end anchored by an anchorage 80 to a central portion of the door 62 and extends through an eyelet 76 and an eyelet 82 in the shelf 42 to a suitable eyelet 84 in a bracket 88 supporting a drum 90 on which it is would and fastened. The drum 90 is fixed to a shaft 92 which is adapted to be selectively manually turned by an external knob 94 located on the front face of the unit. The bracket 88 is fixed to the end wall 43 of the casing 20 by suitable fasteners such as screws 96 while the shaft 92 is provided with sufficient friction to hold the drum 90 in any desired position.

The bulkhead 34 includes a vertically disposed cornpartment or control box 108 with its rear wall 110 and top wall 111 extending inwardly from the casing side wall 42 having the configuration shown to form with the intermediate wall 45 the open front control box 108. A vertical partition and locating wall 116 extends inwardly in a transverse manner from intermediate wall 45 on side wall 44 and are joined by shroud side wall 54 supported on either side by overlapping the inner surface thereof and is affixed thereto by suitable means such as screws 122. The scroll housing side wall 54 is preferably molded of high impact polystyrene and has a stiffening ribs 124 integrally formed thereon. The blower scroll side wall 54 together with the locating wall 116 form a composite partitioning wall defining one side of the evaporator chamber 36.

As best seen in FIG. 3, an elongated rectangular fresh air inlet opening 127 in communication with the outer compartment 38 is formed by a rectangular opening 128 in the blower scroll housing side wall 54 aligned in a flush manner with rectangular opening 130 in the locating wall 116. It should be noted that in the disclosed form side wall 54 is formed integral with the horizontal shelf 42 and includes a normally extending side flange 132 in juxtaposition to the casing side wall 44 so as to be suitably secured thereto as by screws 134 as shown in FIG. 1. An arcuate flange 138 extending vertically from an intermediate portion of the shelf 40 forms a side wall of cutoff portion 57 and is secured thereto by screw 140.

The centrifugal room air fan, which includes the combination of the blower wheel 51 in the scroll housing 52 is arranged to create a negative pressure differential in the evaporator chamber 36 which draws room air through the evaporator 50 such that the room air is drawn into the blower scroll housing through inlet orifice 53 and forced out through outlet 56 into the discharge duct 46 through which conditioned air or recirculated air is directed back into the room through the opening 48 in the front wall of the unit.

For the purpose of regulating the flow of outside or make-up air through the rectangular vertically oriented fresh air opening 127, foldable door means 151) consisting of a one-piece molded plastic member, the principal parts thereof including a first hinge panel 152, a second hingedly-connected cover panel 154 and a thirdly hingediy-connected baffle panel 156 fabricated in the form of a one-piece blank and preferably molded of polypropylene plastic material. By virtue of applicants construction a first integrally molded hinge 160 is provided between the hinge panel 152 and the cover panel 154 and a second integral molded hinge 162 is provided between the second cover panel 154 and the third baffle panel 156.

As seen in FIG. 3 a pair of coextensive vertically extending horizontally spaced rib members 1641 and 165 are formed in integrally molded fashion on the scroll housing side wall 116 to provide a vertical channel or slot 168 therebetween for reception of the first hinge panel 152 therein. The base of slot 168 has a plurality of elongated rectangular apertures 170 located therein (FIG. 6) dimensioned for releasably retaining respective pairs of generally parallel leg portions 172, 173, each of which terminates with integral barbed end portions 174, 175 including an outwardly directed retaining flange adapted to engage and hold the partition or locating wall 116 outer surface. The leg members have rounded cutout portions 176, 177 and 178 to increase the length of the legs and thereby increase their elasticity.

The apertures 170 are of sufficient height to receive the inwardly flexed hooked or barbed ends of respective leg portions so that they may lock the retaining flanges against the locating wall 116. It will be noted that by virtue of the hinge panel 152 extending normally to the

walls

54 and 116 the hinge means for the cover panel in the form of first hinge 160 is positioned about midway between the partition wall and the inner surface 171 of the evaporator 50 to allow the foldable door assembly to block-off a substantial portion of the evaporator surface when actuated to its fresh air open position through an acute angle of about 40 in the present embodiment.

Each of the first and second

flexible hinges

160 and 162 in the disclosed form consist of a fold line having a greatly reduced thickness in which a series of aligned slots 163 are located forming a series of flesible straps serving as a distinct pivotal axis for each of the panels. It should be noted that in its unstressed or unbiased position the baffle panel 156 is oriented in a substantially coplanar manner with the cover panel 154.

As best seen in FIG. 4 the flexible hinge is located in substantial flush arrangement with the inner surface of the cover or door panel 154 while the flexible hinge 162 is located in flush arrangement with the outer surface of the cover panel 154 and the baffle panel 156 arrangement. With the cover panel obliquely oriented in closed position the panel 156 is pivotally biased from its coplanar neutral position in a first outwardly flexed direction in flush contact with

composite partitioning wall

54, 116 intermediate fresh air opening 127 and scroll intake orifice 53 with the second flexible hinge 162 is positioned in a sealed manner along and coextensive with the inboard vertical edge of the fresh air opening. When actuating means to be described move the cover panel 154 to its open position the free edge of the baffle panel contacts the evaporator inner surface causing the baffle panel to be biased in an overcenter position (FIG. 4).

As best seen in FIGS. 2 and 4 the fresh air opening is formed in an oblique manner by C-shaped frame or door jamb means comprising horizontal

triangular end members

180, 182 and vertical rib which positions the cover panel 154 at an inwardly canted or oblique angle of about 20 with respect to wall 54. The C- shaped frame extends into the chamber 36 and is shown formed integral with the locating wall 116 such that their inwardly sloped edges 184 cause the cover panel to form oblique upper and lower jambs for seating or contacting the resilient backing portion 186 of the cover panel 154 in a sealed manner. Extending toward the pivotal hinge 162 of the second cover panel 154 is a mousetrap spring 190 having curled portions 192 positioned over the hinge 160 and having projecting U-shaped loop 193 engaging a longitudinal strengthening rib 194 integrally molded along the forward edge of the cover panel 154. The spring 190 has its

legs

198 and 199 fixedly supported within the longitudinal channel 168 by means of book portions the uppermost one being shown at 200 formed on the extremity of leg 198 extending into tapered opposed spherical grooves 206 (FIG. 2) molded in

rib members

164, 165. The mousetrap spring 190 is biased to maintain the cover panel backing 186 in sealed contact with the oblique edges 184 and the inboard edge of opening 128.

It will be seen in FIG. 3 that the baffle panel 156 is biased by spring 190 in flush relation with the blower scroll side wall 54 and occupies an area adjacent the edge of the bellmouth orifice 53 of the scroll without obstructing the'entrance of recirculated air through the orifice 53. Upon the cover panel 154 being pivoted about its hinges 160 to its open position, it will be noted that the baffle panel 156 is located such that its triangular stiffening ribs 202, 203, vertically spaced on the outer surface of panel 156, contact the inner surface 171 of the evaporator 50 such that the free edge of baffle panel 156 is maintained in substantially sealed contact with evaporator surface 171 while

panels

154 and 156 serve to direct fresh air entering combined inlet 127 toward the scroll orifice 53. It will be seen that in its opened position the foldable damper door assembly 150 is positioned to substantially block-off or close about 25 percent of the evaporator inner surface 171 and thereby increase the negative pressure differential within the evaporator chamber 36 serving to induce an increased amount of fresh air into the chamber 36 for introduction into the blower scroll inlet orifice 53. By

applicants arrangement of locating the first hinge 160 intermediate the sidewalls of chamber 36 the foldable damper door is able to block-off a proportionally greater area of the evaporator inner surface 171. It will be noted that the cover panel 154 is also provided with transverse

stiffening ribs

207 and 208 which also serve with ribs 202 and 203 to block or reduce the vertical passage of recirculated air moving through the evaporator chamber 36.

As seen in FIG. 4 a U-shaped bracket 220 is secured to the blower scroll arcuate wall 55 by means of threaded fastener 222 to support a reciprocating rod member 224 the forward end of which engages the damper door cover panel 154 adjacent the flexible hinge 162 while the rear portion of the rod 224 has secured thereon a control cord 228 which extends through an eyelet 230 in angle bracket 232 secured by screw 233 to the outer surface of the locating wall 116 and as seen in FIG. 1 through an eyelet means in 234 in wall 45 through the eyelet 82 common with the control cable 78 so as to be wrapped around the spool 90 in a direction opposite to that of the cable 78 such that control knob 94 controls both the fresh air damper double hinge door 150 and the exhaust door 62, depending upon whether the knob is rotated in a clockwise or counterclockwise direction.

It is seen from FIG. 4 that rotating the knob in one direction will cause a pull on the cable 228 which will direct the rod 224 outwardly to move the double hinge damper door under the influence of spring 190 to its position shown in FIG. 4. It will be appreciated that when double hinge door 150 is in its evaporator blocking position shown in FIG. 4 such that the pair of triangular shaped abutment ribs 202, 204 are positioned with their outer edge engaging the inner surface 171 of the evaporator unit 50 such that the baffle door portion 156 is arranged in an oblique manner to the evaporator inner wall 171 so as to smoothly direct the flow of incoming fresh air into the inlet 53. It will be noted that the evaporator 50 is enclosed in a frame, preferably formed of sheet metal, the side walls of which are shown at 240 and 242 which serve to enclose the evaporator compartment 36.

While the embodiment of the present invention constitutes a preferred form, it is to be understood that other forms might be adopted.

1 claim:

1. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall having a centrifugal fan scroll housing air intake orifice therein for receiving a stream of indoor air withdrawn from the enclosure and through said evaporator compartment for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fresh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel in said fan scroll housing having its axis substantially normal to said partition wall, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door comprising a first hinge panel, a second cover panel and a third baffle panel serially arranged in the order named so as to be flexibly interconnected along their common vertical edges by first and second integral hinges, means for fixedly supporting said hinge panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said hinge panel extending normally from said partition wall a defined distance toward the inner surface of said evaporator, said second cover panel being biased to a foldable first obliquely oriented fresh air closed position wherein said second flexible hinge is positioned'in a sealed manner along and coextensive with the inboard vertical edge of said fresh air opening, frame means positioned above and below said fresh air opening so as to contact in a sealed manner the upper and lower edges of said closed cover panel, said baffle panel in its unstressed condition being oriented in coplanar relation with said cover panel whereby said baffle panel is folded in a first direction so as to be positioned in flush contact with said partition wall intermediate said fresh air opening and said scroll intake orifice, actuating means for moving said foldable door cover panel pivotally about its first flexible hinge from its biased closed position through a defined acute angle to a fresh air open position wherein the free edge of said baffle panel sealingly contacts the inner surface of said evaporator by said baffle panel being folded in a second direction about said flexible hinge, said foldable door in said fresh air open position being operative to substantially block-offa defined outboard portion of said evaporator inner surface to thereby increase the negative pressure within said evaporator chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure.

2. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall having a centrifugal impeller scroll housing air intake orifice therein for receiving a stream of air withdrawn from the enclosure and through said evaporator compartment for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fresh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel operatively supported in said scroll housing, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door including a cover panel and a baffle panel flexibly inter connected along their common vertical edges by an integral hinge, pivoting rneans supporting said cover panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said pivoting means being located substantially intermediate said partition wall and said evaporator inner surface, means biasing said cover panel to a foldable first inwardly canted fresh air closed position overlying said fresh air opening wherein said flexible hinge is positioned in a sealed manner adjacent to and coextensive with the inboard vertical edge of said fresh air opening, frame means positioned around said fresh air opening so as to contact in a sealed manner the upper, lower and outboard edges of said closed cover panel, said baffle panel in its unbiased condition being oriented in coplanar relation with said cover panel whereby said baffle panel is folded about said integral hinge in a first overcenter direction upon its free vertical edge contacting said partition wall causing said baffle panel to be positioned in flush contact with said partition wall intermediate said fresh air opening and said scroll housing intake orifice, actuating means for moving said foldable door cover panel about said pivoting means from its biased inwardly canted closed posi tion through a defined acute angle to an outwardly canted fresh air open position wherein said baffle panel is folded in a second overcenter direction upon the free vertical edge of said baffle panel contacting said evaporator inner surface, said cover and baffle panels in their fresh air open position being operative to substantially block-off a defined portion of said evaporator inner surface to thereby increase the negative pressure differential within said evaporator plenum chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure,

3. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall including one side wall of a centrifugal fan scroll housing having a recirculated air intake orifice therein for receiving a stream of air withdrawn from the enclosure and through said evaporator compartment into said housing for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fresh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel in said fan scroll housing having its axis substantially normal to said partition wall, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door comprising a first hinge panel, a second cover panel and a third baffle panel serially arranged in the order named so as to be flexibly interconnected along their common vertical edges by first and second integral hinges, engaging means for releasably retaining said hinge panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said engaging means including pairs of integral flexible legs projecting from the free edge of said hinge panel, said legs being engaged in respective apertures in said partition wall by means of an integral barbed portion formed on the end thereof, said hinge panel extending normally from said partition wall a defined distance toward the inner surface of said evaporator whereby said first integral hinge is oriented approximately midway between said partition wall and said evaporator, said second cover panel being biased to a foldable first inwardly canted fresh air closed position wherein said second flexible hinge is positioned in a sealed manner adjacent and coextensive with the inboard vertical edge of said fresh air opening, frame means in the form of C-shaped door jamb including triangular end members positioned above and below said fresh air opening so as to contact in a sealed manner the upper and lower edges of said closed canted cover panel, said baffle panel in its unbiased condition being oriented in coplanar relation with said cover penal whereby said baffle panel is folded in a first direction so as to be biased in flush contact with said partition wall intermediate said fresh air opening and said scroll intake orifice, actuating means for moving said foldable door cover panel pivotally about said first flexible hinge from its biased closed position through a defined acute angle of about 40 to a fresh air open position wherein the free edge of said baffle panel sealingly contacts the inner surface of said evaporator by said baffle panel being folded over-center in a second direction about said second flexible hinge, said foldable door panels in said fresh air open position being operative to substantially block-off a defined outboard portion of said evaporator inner surface to thereby increase the negative pressure within said evaporator plenum chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure.

Claims

1. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall having a centrifugal fan scroll housing air intake orifice therein for receiving a stream of indoor air withdrawn from the enclosure and through said evaporator compartment for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fresh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel in said fan scroll housing having its axis substantially normal to said partition wall, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door comprising a first hinge panel, a second cover panel and a third baffle panel serially arranged in the order named so as to be flexibly interconnected along their common vertical edges by first and second integral hinges, means for fixedly supporting said hinge panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said hinge panel extending normally from said partition wall a defined distance toward the inner surface of said evaporator, said second cover panel being biased to a foldable first obliquely oriented fresh air closed position wherein said second flexible hinge is positioned in a sealed manner along and coextensive with the inboard vertical edge of said fresh air opening, frame means positioned above and below said fresh air opening so as to contact in a sealed manner the upper and lower edges of said closed cover panel, said baffle panel in its unstressed condition being oriented in coplanar relation with said cover panel whereby said baffle panel is folded in a first direction so as to be positioned in flush contact with said partition wall intermediate said fresh air opening and said scroll intake orifice, actuating means for moving said foldable door cover panel pivotally about its first flexible hinge from its biased closed position through a defined acute angle to a fresh air open position wherein the free edge of said baffle panel sealingly contacts the inner surface of said evaporator by said baffle panel being folded in a second direction about said flexible hinge, said foldable door in said fresh air open position being operative to substantially blockoff a defined outboard portion of said evaporator inner sUrface to thereby increase the negative pressure within said evaporator chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure.

2. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall having a centrifugal impeller scroll housing air intake orifice therein for receiving a stream of air withdrawn from the enclosure and through said evaporator compartment for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fresh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel operatively supported in said scroll housing, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door including a cover panel and a baffle panel flexibly interconnected along their common vertical edges by an integral hinge, pivoting means supporting said cover panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said pivoting means being located substantially intermediate said partition wall and said evaporator inner surface, means biasing said cover panel to a foldable first inwardly canted fresh air closed position overlying said fresh air opening wherein said flexible hinge is positioned in a sealed manner adjacent to and coextensive with the inboard vertical edge of said fresh air opening, frame means positioned around said fresh air opening so as to contact in a sealed manner the upper, lower and outboard edges of said closed cover panel, said baffle panel in its unbiased condition being oriented in coplanar relation with said cover panel whereby said baffle panel is folded about said integral hinge in a first overcenter direction upon its free vertical edge contacting said partition wall causing said baffle panel to be positioned in flush contact with said partition wall intermediate said fresh air opening and said scroll housing intake orifice, actuating means for moving said foldable door cover panel about said pivoting means from its biased inwardly canted closed position through a defined acute angle to an outwardly canted fresh air open position wherein said baffle panel is folded in a second overcenter direction upon the free vertical edge of said baffle panel contacting said evaporator inner surface, said cover and baffle panels in their fresh air open position being operative to substantially block-off a defined portion of said evaporator inner surface to thereby increase the negative pressure differential within said evaporator plenum chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure.

3. In an air conditioning unit for conditioning the air within an enclosure the combination comprising: a casing enclosing a condenser compartment housing a condenser and an evaporator compartment housing an evaporator separated by a transverse partition wall, said partition wall including one side wall of a centrifugal fan scroll housing having a recirculated air intake orifice therein for receiving a stream of air withdrawn from the enclosure and through said evaporator compartment into said housing for subsequent discharging of the recirculated air into the enclosure, said evaporator compartment including a plenum chamber defined between said partition wall and the inner face of said evaporator, a rectangular shaped fResh air opening in said partition wall adjacent one end of said plenum chamber in communication with said condenser compartment, a blower wheel in said fan scroll housing having its axis substantially normal to said partition wall, said fresh air opening in said partition wall spaced a defined distance from said scroll housing intake orifice, an integrally molded foldable door comprising a first hinge panel, a second cover panel and a third baffle panel serially arranged in the order named so as to be flexibly interconnected along their common vertical edges by first and second integral hinges, engaging means for releasably retaining said hinge panel on the evaporator compartment side of said partition wall adjacent the outboard vertical edge of said fresh air opening, said engaging means including pairs of integral flexible legs projecting from the free edge of said hinge panel, said legs being engaged in respective apertures in said partition wall by means of an integral barbed portion formed on the end thereof, said hinge panel extending normally from said partition wall a defined distance toward the inner surface of said evaporator whereby said first integral hinge is oriented approximately midway between said partition wall and said evaporator, said second cover panel being biased to a foldable first inwardly canted fresh air closed position wherein said second flexible hinge is positioned in a sealed manner adjacent and coextensive with the inboard vertical edge of said fresh air opening, frame means in the form of C-shaped door jamb including triangular end members positioned above and below said fresh air opening so as to contact in a sealed manner the upper and lower edges of said closed canted cover panel, said baffle panel in its unbiased condition being oriented in coplanar relation with said cover penal whereby said baffle panel is folded in a first direction so as to be biased in flush contact with said partition wall intermediate said fresh air opening and said scroll intake orifice, actuating means for moving said foldable door cover panel pivotally about said first flexible hinge from its biased closed position through a defined acute angle of about 40* to a fresh air open position wherein the free edge of said baffle panel sealingly contacts the inner surface of said evaporator by said baffle panel being folded over-center in a second direction about said second flexible hinge, said foldable door panels in said fresh air open position being operative to substantially block-off a defined outboard portion of said evaporator inner surface to thereby increase the negative pressure within said evaporator plenum chamber thereby causing fresh air to be induced through said fresh air opening for movement into said scroll housing intake orifice for mixture with recirculated air from the enclosure.