US3218952A

US3218952A - Devices for producing air screens

Info

Publication number: US3218952A
Application number: US194329A
Authority: US
Inventors: Ernest F Gygax
Original assignee: Universal Match Corp
Current assignee: Universal Match Corp
Priority date: 1962-05-14
Filing date: 1962-05-14
Publication date: 1965-11-23
Anticipated expiration: 1982-11-23

Description

E. F. GYGAX DEVICES FOR PRODUCING AIR SCREENS Nov. 23, 1965 Filed May 14, 1962 5 Sheets-Sheet 1 INVENTOR.

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Nov. 23, 1965 E. F. GYGAX 3,218,952

DEVICES FOR PRODUCING AIR SCREENS Filed May 14, 1962 5 Sheets-Sheet 2 G O 0 O 9 1 4 1 7 7 Fig.4.

INVENTOR.

Nov. 23, 1965 E. F. GYGAX DEVICES FOR PRODUCING AIR SCREENS Filed May 14, 1962 Z5 Sheets-Sheet 3 l/Vl/EA/TOR ERNEST F2 GYGAX HTTORA/EY United States Patent 3,218,952 DEVICES FOR PRODUCING AIR SCREENS Ernest F. Gygax, Glendale, Mo., assignor to Universal Match Corporation, Ferguson, Mo., a corporation of Delaware Filed May 14, 1962, Ser. No. 194,329 5 Claims. (Cl. 98-36) This invention relates to improvements in Devices For Producing Air Screens. More particularly, this invention relates to improvements in devices for producing air screens for freezer rooms.

It is, therefore, an object of the present invention to provide an improved device for producing an air screen for a freezer room.

The atmospheres within freezer rooms are customarily maintained at temperatures below zero Fahrenheit. To make it possible to maintain those atmospheres at such low temperatures, despite high ambient temperatures external of those freezer rooms, it has been customary to provide the doorways of freezer rooms with doors that were normally kept closed but that could be opened Whenever objects were to be taken into or removed from those rooms. Those doors did help maintain the atmospheres within the freezer rooms at temperatures below zero Fahrenheit, but the use of those doors has created a number of problems. For example, where those doors have been made so there were only small air gaps between the edges of those doors and the frames of the doorways, ice tended to form in those air gaps when those doors were left closed for substantial periods of time, as for example, over night or over a weekend. Either electric heating wires had to be mounted on the frames of the doorways to keep ice from forming, or the ice that did form had to be removed by ice picks or scrapers before the doors could be opened. On the other hand, Where those doors have been made so there were large air gaps between the edges of those doors and the frames of the doorways, the influx of warm air into the freezer rooms and the elflux of cold air from those freezer rooms has been excessive. As a result, doors for the doorways of freezer rooms havenot proven to be satisfactory.

Where doors are used to selectively close the doorways of freezer rooms, the time spent in recurrently opening and closing those doors, as objects are moved into and out of those rooms, can become a substantial cost factor. Specifically, if persons are delegated to take care of the opening and closing of the doors for the doorways of freezer rooms, those persons will be idle for appreciable portions of each working day. On the other hand, if the persons moving objects into and out of the freezer rooms must open and then close the doors for the doorwaysof those rooms, those persons will be unable to devote all of their time to the moving of objects into and out of the freezer rooms. For this additional reason, doors for the doorways of freezer rooms have not proven to be satisfactory.

The use of doors for the doorways of freezer rooms is additionally objectionable because those doors frequently fail to move freely to fully-open position; and where that happens those doors can be struck by the forklift trucks which are used to move objects into and out of those rooms. The striking of those doors by those forklift trucks can injure those doors and the objects being move-d into and out of the freezer rooms, and can also lead to traffic jams in the doorways. Traffic jams can occur in those doorways even under normal conditions, unless the doors of the freezer rooms are provided with windows and those windows are kept free of fog or frost, because forklift trucks approaching the opposite sides 3,218,952 Patented Nov. 23, 1965 of the doorways of freezer rooms frequently follow collision courses. Then, when the doors are opened, backing of one or more of the forklift trucks-with accompanying losses of time-becomes necessary. For all of these reasons, it would be desirable to eliminate the need of opening and closing of doors for the doorways of freezer rooms. The present invention makes it possible to eliminate the opening and closing of the door for the doorway of a freezer room and it does so by providing a device which produces an air screen for the doorway of a freezer room that will perform the functions of a door for that room but that will be free of the objections associated with the use of a door.

The device provided by the present invention directs a screen of air across the doorway of a freezer room and thereby effectively closes that doorway. However, that screen of air will not block vision, as do the doors heretofore used to close the doorways of freezer rooms. Further, that screen of air will permit free and ready ingress and egress of personnel and of forklift trucks; and will thus save the time that has heretofore been spent in the opening and closing of the doors of freezer rooms. Furthermore, that screen of air will prevent the accidents and delays that arose when forklift trucks approached the doorways in opposite directions on collision courses. Moreover, that screen of air will prevent the injuries and delays that resulted when forklift trucks struck the doors of freezer rooms.

The air screen provided by the present invention will also obviate other problems systemic to the use of doors for the doorways of freezer rooms. For example, that air screen will materially reduce the influx of warm air into a freezer room and will materially reduce the efllux of cold air out of that room. Such a material reduction is important because it substantially reduces the loss of cooling effect. It must be remembered that whenever the doors of freezer rooms are opened, warm air is free to flow into those rooms and cold air is free to fiow out of those rooms; and in one freezer room the resulting loss of cooling effect was approximately four hundred British Thermal Units per degree of Fahrenheit differential per square foot of opening per hour. When that doorway was protected by an air screen provided by the present invention, that loss of cooling effect was reduced from four Ihundred to just five British thermal units per degree Fahrenheit differential per square foot of opening per hour.

The influx of warm air into freezer rooms creates fog in, and adjacent to, the doorways of those rooms, and also causes moisture to condense on the heat-exchanging surfaces within those rooms, and the condensate then turns to frost. Any fog in, and adjacent to, the doorways of freezer rooms reduces visibility and increases the likelihood of collisions. Any deposit of frost on the heatexchanging surfaces within freezer rooms is objectionable because it progressively decreases the efiiciency of those heat-exchanging surfaces, and also because it requires frequent shut downs of those rooms to permit defrosting of those heat-exchanging surfaces. The reduced influx of warm air into freezer rooms, which is made possible by the air screen of the present invention, is important in eliminating fog in, and adjacent to, the doorways of those rooms. Further, that reduced influx of warm air is important in reducing the depositing of frost upon the heat-exchanging surfaces in the freezer rooms.

The efflux of cold air from freezer rooms can cause ice and frost to accumulate on the floors adjacent the doorways of those rooms. The accumulation of ice and frost adjacent those doorways is dangerous because it makes it easy for persons and forklift trucks to slip and skid as they approach those doorways. The reduced efflux of' cold air from freezer rooms, which is made possible by the air screen of the present invention, is important in reducing the accumulation of frost and ice on the floors immediately adjacent the doorways of those rooms. Hence, the air screen of the present invention promotes safety and reduces the risk of accidents.

To establish a useful air screen for the doorway of a freezer room, it is not suflicient to merely blow a mass of air across that doorway. Instead, it is necessary to provide longitudinally-directed and laterally-directed components of force within the masses of air used to form the air screen. Specifically, the mass of air adjacent the top of the doorway must be given a laterally-directed component of force so it will pass completely across that doorway, and that mass of air must be given a longitudinally-directed component of force so it will match and withstand the forces applied by warm air attempting to enter the freezer room. Also, the mass of air adjacent the bottom of the doorway must be given a laterallydirected component of force so it will pass completely across that doorway, and that mass of air must be given a longitudinally-directed component of force so it will match and withstand the forces applied by cold air attempting to leave the freezer room. The present invention provides the required components of force for the mass of air adjacent the top of the doorway by giving that mass of air an inclination which causes it to move into the area external of the freezer room; and it provides the required components of force for the mass of air adjacent the bottom of the doorway by giving that mass of air an inclination which causes it to move into the freezer room. It will be noted that the longitudinally-directed components of force in the air masses adjacent the top and bottom of the doorway are oppositely-directed; and those oppositely-directed components of force will interact with the forces applied by the warm air adjacent the top of the doorway and by the cold air adjacent the bottom of that doorway to substantially prevent any interchange of air between the freezer room and the warm area external of that room. It is, therefore, an object of the present invention to provide a device which will cause the mass of air adjacent the top of the doorway of a freezer room to incline outwardly into the warm area adjacent that doorway and which will cause the mass of air adjacent the bottom of that doorway to incline inwardly into the freezer room.

The two masses of air of the air screen will issue from an air discharge chamber adjacent one side of a doorway and will be directed toward an air inlet chamber adjacent the opposite side of that doorway; and a reduced pressure adjacent that air inlet chamber will attract those masses of air and thereby help maintain the integrity of the air screen. That air inlet chamber has a large inlet opening and has perforate members which are disposed within that opening to subtend an obtuse dihedral angle. Those perforate members serve as diffuses and flowequalizers; and they create a uniform fiow for the air screen as it approaches the air inlet chamber, despite the opposite inclinations given the upper and lower portions of the air of that air screen as they left the air discharge chamber. It is, therefore, an object of the present invention to provide an air inlet chamber, adjacent the doorway of a freezer room, which has a large inlet opening and which has perforate members disposed within that opening to subtend an obtuse dihedral angle.

In theory, the effectiveness of an air screen can be increased by increasing the velocity of the air used to form that air screen. However, the present invention provides an effective air screen and yet avoids the use of excessively fast air in producing that air screen. Specifically, the present invention limits the velocity of the air used in the air screen for a freezer room to values in the range of from one thousand to fifteen hundred feet per minute; and, in doing so, minimizes the induction into that air screen of cold air from the freezer room and minimizes the induction into that air screen of warm air from the area external of that room. By minimizing the induction into that air screen of cold air from the freezer room, the present invention minimizes the condensing of moisture on portions of the air chambers provided by that invention; and by minimizing the induction into that air screen of warm air from the area external of that room, the present invention keeps fog from forming in, or adjacent to, the doorway of that room. It is, therefore, an object of the present invention to provide an air screen for a freezer room wherein the velocity of the air is in the range of from one thousand to fifteen hundred feet per minute.

The air discharge chamber and the air inlet chamber provided by the present invention are mounted externally of the freezer room. This is important because it prevents any condensate which forms in those chambers from turning to frost or ice. Further, it keeps the temperature of the air in the air screen at sufficiently high levels to keep that air from constituting a cold blast on persons moving into and out of the freezer room. It is, therefore, an object of the present invention to dispose the air discharge chamber and the air inlet chamber of an air screen for a freezer room externally of that room.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be defined by the appended claims.

In the drawing, FIG. 1 is a front elevational view of one preferred form of device, for producing an air screen adjacent a freezer room, that is made in accordance with the principles and teachings of the present invention,

FIG. 2 is an elevational view of the right-hand end of the device of FIG. 1,

FIG. 3 is a sectional plan view through the device of FIG. 1 and through part of the wall of the freezer room, and it is taken along the plane indicated by the line 3-3 in FIG. 1,

FIG. 4 is a partially-broken elevational view, on a large scale, of the air-discharging assembly of the device of FIG. 1, and it is taken along the plane indicated by the line 44 in FIG. 1,

FIG. 5 is a sectional bottom view, on a still larger scale, through the air-discharging assembly of FIG. 4, and it is taken along the plane indicated by the line 55 in FIG. 4,

FIG. 6 is a sectional bottom view, on the scale of FIG. 5, through the air-discharging assembly of FIG. 4, and it is taken along the plane indicated by the line 6-6 in FIG. 4,

FIG. 7 is another sectional bottom view, on the scale of FIG. 5, through the air-discharging assembly of FIG. 4, and it is taken along the plane indicated by the line 77 in FIG. 4, and

FIG. 8 is a diagrammatic view of the flow lines within the air screen produced by the device of FIG. 1,

FIG. 9 is a view, on a larger scale, of the perforate members mounted within the air inlet chamber of FIG. 1, and

FIG. 10 is a perspective, diagrammatic view of the air-discharging assembly of FIG. 4.

Referring to the drawing in detail, the numeral 20 generally denotes a freezer room that can have the temperatures of the atmosphere therein maintained below zero fahrenheit. The walls of that room will be suitably insulated, and suitable heat-exchanging surfaces will be mounted in that room to provide the desired cooling effect. One wall of that room is generally denoted by the numeral 2 2; and that wall has a doorway 24 therein. That doorway will be wide enough to permit at least one forklift truck, and preferably will be wide enough to permit at least two. forklift trucks, to pass through it. The numeral 26 generally denotes an area. which is external of the freezer room .20, and the atmosphere within that area will usually be warmer than the atmosphere within that freezer room. Preferably, the area 26 will not be out of doors, because such an area could be exposed to heavy winds; and such winds could interfere with proper operation of the air screen provided by the device of FIG. 1.

The numeral 28 denotes an air discharge chamber that is located adjacent the left-hand side of the doorway 24. That air discharge chamber is a three-sided chamber, and the open side of that chamber is adjacent the doorway. A pan 29 underlies the air discharge chamber 28, and any condensate which drips from or runs down that chamber will be collected and held by that pan. As a result, that pan helps reduce the amount of moisture on the floor adjacent the doorway 24. Vertically-extending flanges 30 are formed at the free edges of the front and rear walls of the chamber 28, and those flanges are parallel to the left-hand wall of that chamber. Those flanges extend toward each other and coact to define the air discharge opening for the air discharge chamber 28. An access door 31 is provided to cover an access opening in the front wall of the chamber 28.

. The numeral 21 denotes a plate that is disposed within the air discharge chamber 28, adjacent the bottom of that chamber; and that plate inclines downwardly from upper left to lower right. The numeral 23 denotes a second plate that is disposed within the air discharge chamber 28 adjacent the center of that chamber; and the upper part of that plate is vertically-directed while the lower part of that plate inclines downwardly from upper left to lower right. The numeral 25 denotes a third plate that is disposed within air discharge chamber 28, adjacent the upper right-hand part of that chamber; and the upper part of that plate is vertically-directed while the lower part of that plate inclines downwardly from upper left to lower right. The plates 21, 23 and 25 span the distance between the front and rear walls of the chamber 28, and the plates 23 and 25 subdivide that chamber into three passages; the passage to the right of the plate 25 terminating about one-third of the way down from the top of that chamber, the passage between plates 23 and 25 terminating about two-thirds of the way down from the top of that chamber, and the passage to the left of the plate 23 terminating at the bottom of that chamber.

The numeral 106 denotes a duct atop the air discharge chamber 28; and the numeral 27 denotes a generally L- shaped extension, within that duct, of the plate 23. A pivot is provided at the right-hand end of that extension; and a deflector 33 is mounted for rotation about that pivot, as indicated by the arcuate line adjacent that deflector. The numeral 35.denotes an L-shaped extension, within the duct 106, of the plate 25; and a pivot is provided at the right-hand end of that extension. A deflector 37 is mounted for rotation about that pivot, as indicated by the arcuate line adjacent that deflector.

The numeral 32 denotes an angle iron frame that is rectangular in elevation and that has one flange thereof telescoped within the discharge opening of the air discharge chamber 28. The other flange of that frame abuts the flanges 30, and that flange is secured to the flanges 30 by machine screws or bolts 34 which either seat in threaded openings in the flanges 30 or extend through unthreaded openings in those flanges and have nuts threaded onto their inner ends. Those machine screws or bolts fixedly secure the angle iron frame angle iron frame 32 to the flanges 30, and thus to the air discharge chamber 28.

Pivot plates

36, 38, 40 and 42 are fixedly secured to the angle iron frame 32, and those plates are grouped. Specifically, pivot plates 36 and 38 are grouped together and are disposed approximately one-third of the way down from the top of the angle iron frame 32, and those pivot plates are below the level of the lower end of the plate 25. The pivot plates 40 and 42 are grouped together and are disposed approximately two-thirds of the way down from the top of the angle iron frame 32, and those pivot plates are below the level of the lower end of the plate 23.

The pivot plate 36 has a set of openings therein which is in register with a similar set of openings in the top of the angle iron frame 32, and those sets of openings will accommodate pivots 46 for air-guiding members 44. The

pivot plates

38 and 40 have sets of openings therein which are in register with each other, andwhich accommodate pivots 64 for air-guiding members 62. The pivot plate 42 and the bottom of the angle iron frame 32 have sets of openings therein which are-in register with each other, and which accommodate pivots 82 for air-guiding members 80. The air-guiding

members

44, 62 and are elongatedprisms that have triangular cross-sections; and those air-guiding members are preferably made hollow to reduce their weight and cost. The

pivots

46, 64 and 82 for the air-guiding

members

44, 62, and 80, respectively, are located adjacent the bases of those members. The

members

44, 62 and 80 are dimensioned so the confronting edges of the bases thereof are spaced apart to define elongated air-discharging openings between them.

The air-guiding members 44 have short plates 48 secured to them, adjacent the apices thereof; and those plates extend outwardly beyond those apices. Pivots 50 rotatably secure the plate 48 to a connecting rod 52. The pivots 50 are spaced apart distances equal to the spacings between the pivots 46; and, as a result, the altitudes of the air-guiding members 44 are parallel to each other. Those altitudes can be caused to assume different angles relative to the plane of the angle iron frame 32 by movement of the connecting rod 52.

The numeral 54 denotes a plate which is suitably secured to the left-hand side of the angle iron frame 32, as shown by FIG. 4; and that plate rotatably supports a bolt 56. A generally similar plate 58 is suitably secured to the right-hand side of the angle iron frame 32, as shown by FIG. 4; and that plate rotatably supports a bolt 60. As indicated particularly by FIG. 5, the bolt 56 is in register with the left-hand side of the base of the left-handmost air-guiding member 44, and the bolt 60 is in register with the right-hand side of the base of the right-handmost air-guiding member 44. The inner ends of the bolts 56 and 60 will, respectively, engage the bases of the left-handmost and right-handmost air-guiding members 44; and those bolts can be adjusted to fix the inclinations of the altitudes of the air-guiding members 44 relative to the plane of the angle iron frame 32. As indicated particularly by FIG. 5, the bolts 56 and 60 are set to cause the altitudes of the air-guiding members 44 to incline outwardly into the area 26, and thus to incline away from the freezer room 20.

The numeral 66 denotes short plates which are secured to the air-guiding members 62 adjacent the apices of those members. Pivots 68 secure those short plates to a connecting rod 70. The pivots 68 are spaced apart distances equal to the spacings between the pivots 64; and, as a result, the altitudes of the air-guiding members 62 are parallel to each other. Those altitudes can be caused to assume different angles relative to the plane of the angle iron frame 32 by movement of the connecting rod 70.

The numeral 72 denotes a plate which is comparable to the plate 54, and which is secured to the left-hand side of. the angle iron frame 32. That plate adjustably supports a bolt 74. The numeral 76 denotes a plate which is comparable to the plate 58, and which is secured to the right-hand side of the angle iron frame 32. That plate adjustably supports a bolt 78. The bolt 74 is in register with the left-hand portion of the base of the left-handmost air-guiding member 62, and the bolt 78 is in register with the right-hand portion of the base ,of the right-handmost air-guiding member 62. The inner ends of the

bolts

74 and 78 will, respectively, engage the bases of the left-handmost and right-handmost air-guiding members 62. Adjustment of those bolts will fix the inclinations of the altitudes of the air-guiding members 62 relative to the plane of the angle iron frame 32; and, as shown particularly by FIG. 6, those altitudes will normally be parallel to the plane of the doorway 24.

The numeral 84 denotes short plates which are secured to the air-guiding members adjacent the apices of those members. Pivots 85 secure those plates to a connecting rod 86. The pivots 85 are spaced apart distances equal to the spacings between the pivots 82; and, as a result, the altitudes of the air-guiding members 80 are parallel to each other. Those altitudes can be caused to assume different angles relative to the plane of the angle iron frame 32 by movement of the connecting rod 86.

The numeral 88 denotes a plate which is comparable to the

plates

54 and 72, and which is secured to the left-hand side of the angle iron frame 32. That plate adjustably supports a bolt 90. The numeral 92 denotes a plate which is generally similar to the

plates

58 and 76, and which is secured to the right-hand side of the angle iron frame 32. That plate adjustably supports a bolt 94. The bolt is in register with the left-hand portion of the base of the left-handmost air-guiding member 80, and the bolt 94 is in register with the right-hand portion of the base of the right-handmost air-guiding member 80. The inner ends of the

bolts

90 and 94 will, respectively, engage the bases of the left--handmost and right-handrnost air-guiding members 80. Adjustment of those bolts will fix the inclinations of the altitudes of the air-guiding members 80 relative to the plane of the angle iron frame 32; and, as shown particularly by FIG. 7, those altitudes will incline inwardly of the freezer room 20 and hence Q away from the area 26.

It will thus be seen that the altitudes of the air-guiding members 44 adjacent the upper end of the air discharge chamber 28 incline outwardly toward the area 26, the altitudes of the air-guiding members 62 adjacent the center of the air discharge chamber 28 are parallel to the doorway 24, and the altitudes of the air-guiding members 80 incline inwardly toward the freezer room 20. The inclinations of the altitudes of the air-guiding members 44 relative to the doorway 24 should be between ten and fifteen degrees; and the inclinations of the altitudes of the air-guiding members 80 relative to the doorway 24 should be between ten and fifteen degrees. However, the inclinations of the altitudes of the air-guiding members 44 will be opposite to the inclinations of the altitudes of the air-guiding members 80. As a result, the air-guiding members 44 will provide longitudinally-directed outward components for the air passing through the openings between them, while the air-guiding members 80 will provide longitudinally-directed inward components for the air passing through the openings between them.

The numeral 96 denotes an air inlet chamber which is disposed adjacent the right-hand side of the doorway 24. That air inlet chamber is a three-sided chamber; and the open side of that chamber is adjacent the doorway 24. A pan 98 underlies the air inlet chamber 96, and any condensate which drips from or runs down that chamber will be collected and held by that pan. As a result, that pan helps reduce the amount of moisture on the floor adjacent the doorway 24. Vertically-directed flanges 100 are formed at the free edges of the front and rear walls of the chamber 96, and those flanges are parallel to the righthand wall of that chamber. Those flanges extend toward each other and coact to define the air inlet opening of that air inlet chamber. An angle iron frame 102 has one of the flanges thereof extending into the air inlet opening, and it has the other flange thereof abutting the front faces of the flanges 100, all as shown by FIG. 3. Machine screws or bolts 103 secure the angle iron frame 102 to the flanges 100, as by seating in threaded openings in those flanges or by passing through unthreaded openings in those flanges and having nuts secured on the inner ends thereof.

The numeral 104 denotes perforate members which are mounted within the air inlet opening of the air inlet chamber 96. Those perforate members are inclined relative to that air inlet opening, as shown by FIG. 3. Specifically, the rear perforate members 104 are mounted so they coact with the rear wall of the air inlet chamber 96 to subtend an angle of about seventy-five degrees, while the front perforate members 104 coact with the front wall of the air inlet chamber 96 to subtend an angle of about seventy-five degrees. This is desirable because it enables the front and rear perforate members 104 to coact to subtend an obtuse dihedral angle with its apex extending into the air inlet chamber 96. Such an angle has been found to facilitate the establishment of a relatively large area of reduced pressure adjacent the air inlet opening, and that large area of reduced pressure helps provide a high velocity for the air passing to the air inlet opening. That high velocity is helpful in maintaining the integrity of the air screen.

The perforate members 104 also tend to provide a diffusing action and to equalize the flow of the air into the air inlet chamber. The perforate members 104 have a total open area in excess of sixty percent, and hence they minimize air friction losses and turbulence. The overall areas of the perforate members 104 should preferably be such that the total open areas of those perforate members approximate one and one-half times the total open areas defined by the air-guiding

members

44, 62 and 80. With such a relationship between the open areas of the perforate members 104 and the open areas defined by the

airguiding members

44, 62 and 80, the velocity of the air entering the air inlet chamber 96 can be about threequarters of the velocity of the air issuing from the air discharge chamber 28, even though the average velocity of that issuing air is only between one thousand and fifteen hundred feet per minute. In this way, an air screen can be produced which will maintain its integrity with minimal induction of air from the freezer room and with minimal induction of air from the area 26.

The air duct 106 is horizontally-directed and has the left-hand end thereof disposed above and in communication with the upper end of the air discharge chamber 28. Machine screws or bolts 108 secure that air duct to the air discharge chamber 28 and provide a substantially airtight seal between that duct and that chamber, while also enabling that chamber to support that duct. The air duct 106 has a cover 110, and machine screws or bolts 112 secure that cover to that air duct.

The numeral 114 denotes an air duct which is horizontally-directed and which has the right-hand end thereof disposed above and in communication with the upper end of the air inlet chamber 96. Machine screws or bolts 116 secure that air duct to the air inlet chamber 96 and provide a substantially air-tight seal between that duct and that chamber, while also enabling that chamber to support that duct. The air duct 114 has a cover 118, and machine screws or bolts 120 secure that cover to that air duct.

Air-guiding plates 113, 115 and 117 have the lower ends thereof in the chamber 96 and have the upper ends thereof in the duct 114. Those plates span the distances between the front and rear walls of that chamber and duct, and help guide the air into that duct.

The right-hand end of the air duct 106 is spaced from the left-hand end of the air duct 114, and an axial-flow blower 122 is mounted between those ends. That blower will be suitably secured to the confronting ends of the

ducts

106 and 114 to provide a substantially air-tight seal therebetween. A bracket 124 extends upwardly from the blower 122, and that bracket supports a motor 126. A pulley 128 is mounted on the output shaft of the motor 126, and a belt 130 extends downwardly from that pulley to the pulley of the blower 122. That blower is mounted so it will move air from right to left in FIG. 1.

The numeral 132 denotes a generally U-shaped baflle which extends rearwardly from the rear wall of the air discharge chamber 28 to that portion of the wall 22 which is disposed to the left of the doorway 24. A baffle 134 extends from the right-hand wall of the air inlet chamber 96 in a direction parallel to that portion of the wall 22 which is located to the right of the doorway 24 and then extends rearwardly to engage that portion of that wall. The bafile 134 defines a recess into which the door 136 of the said freezer room will normal-1y be held. A third baffle, not shown, will extend between the

air ducts

106 and 114 and the blower 122 to the portion of the wall 22 which is above the doorway 24. Those three baflles will be suitably connected together and will interact to prevent leakage of air through the spaces between the wall 22 and the

chambers

28 and 96 and the

ducts

106 and 114 and the blower 122. The door 136 will, under all normal conditions, remain within the recess defined by the baflle 134, but it can be moved into position to close the doorway 24 in the event of a power failure or in the event the motor 126 or the blower. 122 must be shut down for servicing or replacement.

In the operation of the device shown in FIG. 1, the motor 126 drives the axial-flow blower 122; and that blower draws air into the air inlet chamber 96, causes that air to turn and move upwardly into the duct 114, causes that air to turn and move horizontally through the blower 122 and into the duct 106, causes that air to turn and move downwardly into the air discharge chamber 28, causes that air to turn and issue from the openings between the air-guiding

members

44, 62 and 80, and then causes that air to move across the doorway 24 and enter the air inlet chamber 96. The capacity of the blower 122 and the openings between the air-guiding

members

44, 62 and 80 are such that the velocity of the air issuing from the air discharge chamber 28 is between one thousand and fifteen hundred feet per minute. That velocity is high enough to cause the air to move across the doorway 24 and enter the air inlet chamber 96 but is not so high as to induce cold air from the freezer room or warm air from the area 26 external of that freezer room to become an appreciable part of the air screen.

The masses of air which issue from the openings between the air-guiding members 44 will generally follow the .path indicated by the flow lines 142 in FIG. 8. As a result, those masses of air will incline into the area 26 external of the freezer room. The warm air in the area 26 will tend to move into the freezer room 20 through the upper portion of the doorway 24, and will thus apply a force to the masses of air following the path indicated by the flow lines 142. That force will be generally perpendicular to the plane of the doorway 24 and will be directed into the freezer room 20. However, that force will be matched and withstood by a longitudinally-directed, outwardly-acting component of force developed within the masses of air issuing from the openings between the air-guiding members 44 by the inclination of those air-guiding members.

The masses of air which issue from the openings between the air-guiding members 62 will follow a path which is generally indicated by the flow line 144 in FIG. 8. The forces which the cold air within the freezer room 20 and the forces which the warm air in the area 26 apply to the masses of air issuing from the openings between the air-guiding members 62 will largely balance each other. As a result, those masses of air can pass directly to the air inlet chamber 96.

The masses of air which issue from openings between the air-guiding members 80 will generally follow the path indicated by the flow lines 140 in FIG. 8. As a result, those masses of air will incline into the freezer room 20. The cold air in the freezer room 20 will tend to move outwardly through the lower portion of the doorway 24 and will thus apply a force to the masses of air following the path indicated by the flow lines 140. That force will be generally perpendicular to the plane of the doorway 24 and will be directed outwardly through that doorway. However, that force will be matched and withstood by a longitudinally-directed, inwardly-acting component of force developed within the masses of air issuing from the openings between the air-guiding members 80.

The overall result is that the masses of air of the air screen will provide a longitudinally-directed, outwardlyacting component of force adjacent the top of the doorway 24, will provide a longitudinally-directed, inwardlyacting component of force adjacent the bottom of that doorway, and will provide substantially no longitudinal-lydirected component of force adjacent the center of that doorway. The longitudinally-directed, outwardly-acting component of force will match and withstand the force which is applied by warm air in the area 26 as that warm air tends to move inwardly through the upper portion of the doorway 24. The longitudinallydirected, inwardlyacting component of force will match and withstand the force which is applied by the cold air in the freezer room 20 as that cold air tends to move outwardly through the lower portion of the doorway 24.

As the masses of air of the air screen move across the doorway 24 and approach the air inlet chamber 96, those masses of air will reach a zone which is generally denoted by the numeral 138 in FIG. 8 and which has a sub-atmospheric pressure. As those masses of air reach that area, those masses of air will be encouraged to enter the air inlet chamber 96. Thereafter, those masses of air will again pass. upwardly through the air inlet chamber 96, horizontally through the duct 114, through the blower 122, through the duct 106, downwardly through the air discharge chamber 28, and then across the doorway 24. In this way, the masses of air are able to establish and maintain a continuous air screen across the doorway 24.

The motor 126 and the blower 122 are intended to operate whenever the door 136 is disposed within the recess defined by the baffle 134; and a switch, not shown, will preferably be provided to energize the motor 126 whenever that door is disposed within that recess. In the event of a power failure or in the event the motor 126 or the blower 122 must be shut down for servicing or replacement, the door 136 can be moved into position to isolate the atmosphere within the freezer room 20 from the atmosphere in the area 26.

The cold air within the freezer room 20 will be denser and heavier than the warm air in the area 26, and hence it will usually require a larger longitudinally-directed component of force to withstand the force applied by that cold air than will be required to withstand the force applied by that warm air. That larger longitudinallydirected component of force can be developed by making theangle between the altitudes of the air-guiding members and the plane of the angle iron frame 32 larger than the angle between the altitudes of the air-guiding members 44 and that plane. That larger longitudinallydirected component of force can also be developed by making the velocity of the masses of air issuing from the openings between the airguiding members 80 larger than the velocity of the masses of air issuing from the openings between the air-guiding members 44. To make the velocity of the masses of air issuing from the openings between the air-guiding members 80 higher than the velocity of the masses of air issuing from the openings between the airguiding members 44, it is only necessary to establish appropriate settings of the deflectors 33 and 37. Specifically, it is only necessary to rotate those deflectors so more air will move downwardly through the passage to the left of the plate 23 than will move downwardly through the passages to the right of that plate; and the resulting greater volume of air supplied to the air-guiding members 80 will provide the desired larger velocity for the masses of air issuing from the openings between those air-guiding members.

The device provided by the present invention can also be used to form an air screen adjacent the doorway of a room which is kept at a high temperature. For example, that device can be used to form an air screen adjacent the doorway of a room wherein steam is used to maintain the temperature well above ambient temperatures. In forming such an air screen the bolts 56 and 60 will be adjusted, relative to the

plates

54 and 58, to cause the airguiding members 44 to have the altitudes thereof inclined inwardly of the room at an angle of from ten to fifteen degrees. As a result, the air passing through the openings between those air-guiding members will have a longitudinally-directed, inwardly-acting component of force that will match and withstand the component of force applied to the upper part of the air screen by warm air attempting to pass outwardly from the room through the upper part of the doorway. Also, in forming that air screen, the

bolts

90 and 94 will be adjusted, relative to the plates 88 and 92, to cause the air-guiding members 80 to have the altitudes thereof inclined outwardly of the room and into the area external of that room at an angle of from ten to fifteen degrees. As a result, the air passing through the openings between the air guiding members 80 will have a longitudinally-directed, outwardly-acting component of force that will match and withstand the component of force applied to the lower part of the air screen by relatively cool air attempting to pass inwardly into the room through the lower part of the doorway. The

bolts

74 and 78 need not be adjusted relative to the

plates

72 and 76 because the altitudes of the air-guiding members 62 should continue to generally parallel the plane of the doorway.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

1. A device for producing an air screen adjacent the doorway of a freezer room which comprises:

(a) an air discharge chamber adjacent one side of said doorway,

(b) said air discharge chamber having a verticallydirected air discharge opening therein,

(c) said air discharge opening being at least as tall as said doorway,

(d) an air inlet chamber adjacent the opposite side of said doorway,

(c) said air inlet chamber having a vertically-directed air inlet opening therein,

( f) said air inlet opening being at least as tall as said doorway,

(g) said air discharge opening being in vertical and horizontal registry with said air inlet opening,

(h) a horizontally-directed duct mounted atop, and in communication with, said air inlet chamber,

(i) a second horizontally-directed duct mounted atop,

and in communication with, said air discharge chamber,

(j) said ducts extending towards each other but terminating short of each other,

'(k) a blower that has the inlet thereof connected to said air inlet chamber by the first said duct and that has the outlet thereof connected to said air discharge chamber by said second duct,

(1) a motor to drive said blower,

(rn) three groups of air-guiding members disposed within said air discharge opening in said air discharge chamber to guide air issuing from said air discharge chamber,

(11) one of said groups of air-guiding members causing air issuing from the upper part of said air discharge opening to incline outwardly into the area external of said freezer room,

(0) a second of said groups of air-guiding members causing air issuing from the lower part of said air discharge opening to incline into said freezer room,

(p) a third of said groups of air-guiding members causing air issuing from the central part of said air discharge opening to move generally parallel to the plane of said doorway,

(q) the air from said upper, central and lower parts of said air discharge opening being directed to move across said doorway and to enter said inlet opening of said air inlet chamber,

(r) the outwardly-inclined air adjacent the upper part of said air discharge chamber applying a longitudinally-directed outwardly-acting component of force which matches and withstands the component of force applied to the air screen by warm air external of said freezer room attempting to enter said freezer room adjacent the upper part of said doorway,

(s) the inwardly-inclined air adjacent the lower part of the air discharge opening applying a longitudinallydirected, inwardly-acting component of force which matches and withstands the component of force applied to the air screen by cold air within said freezer room attempting to issue from said freezer room,

(t) the air from said upper, central and lower parts of said air discharge opening providing an air screen that substantially isolates the atmosphere Within said freezer room from the atmosphere external of said freezer room,

(u) adjustable members that fix the position of said air-guiding members relative to said plane of said doorway,

(v) said adjustable members holding the air-guiding members of the first said group of air-guiding members inclined outwardly of said plane of said doorway at an angle of from ten to fifteen degrees,

-(w) said adjustable members holding the air-guiding members of said second group of air-guiding members inclined inwardly of said plane of said doorway at an angle offrom ten to fifteen degrees,

(x) said adjustable members holding the air-guiding members of said third group of air-guiding members generally parallel to said plane of said doorway,

(y) said air issuing from said upper, central and lower parts of said air discharge opening having velocities in the range of one thousand to fifteen hundred per minute,

(2) perforate members mounted in said air inlet chamber adjacent said air inlet opening,

(aa) said perforate members subtending an obtuse angle having the apex thereof extending into said air inlet chamber,

(ab) said chambers, ducts and blower being spaced from that wall of said freezer room which has the doorway therein, and

(ac) bafiles extending between said freezer room and said chambers, ducts, and blower.

2. A device for producing an air screen adjacent the doorway of a freezer room which comprises:

(a) an air discharge chamber adjacent one side of said doorway,

(b) said air discharge chamber having an air discharge opening therein,

(c) an air inlet chamber adjacent the opposite side of said doorway,

((1) said air inlet chamber having an air inlet opening therein,

(e) a blower that has the inlet thereof connected to said air inlet chamber and that has the outlet thereof connected to said air discharge chamber, and

(f) an air-discharging assembly disposed within said air discharge opening in said air discharge chamber to guide air issuing from said air discharge chamber,

(g) said air-discharging assembly causing air issuing from the upper part of said air discharge opening to incline outwardly into the area external of said freezer room,

(h) said air-discharging assembly causing air issuing from the lower part of said air discharge opening to incline into said freezer room,

(i) the outwardly-inclined air adjacent the upper part of said air discharge chamber applying a longitudinally-directed outwardly-acting component of force which matches and withstands the component of force applied to the air screen by warm air external of said freezer room attempting to enter said freezer room adjacent the upper part of said doorway,

(j) the inwardly-inclined air adjacent the lower part of the air discharge opening applying a longitudinallydirected, inwardly-acting component of force which matches and withstands the component of force applied to the air screen by cold air within said freezer room attempting to issue from said freezer room,

(it) perforate members mounted in said air inlet chamber adjacent said air inlet opening,

(1) said perforate members subtending an obtuse angle having the apex thereof extending into said air inlet chamber.

3. A device for producing an air screen adjacent the doorway of a freezer room which comprises:

(a) an air discharge chamber adjacent one side of said doorway,

(b) said air discharge chamber having an air discharge opening therein that is deep in the direction of traific flow through said doorway,

(c) an air inlet chamber adjacent the opposite side of said doorway,

((1) said air inlet chamber having an air inlet opening therein that is deep in the direction of trafiic flow through said doorway,

(e) a blower that has the inlet thereof connected to said air inlet chamber and that has the outlet thereof connected to said air discharge chamber,

(f) a motor to drive said blower,

(g) three groups of air-guiding members disposed within said air discharge opening in said air discharge chamber to guide air issuing from said air discharging chamber, each group comprising spaced, parallel air guiding members, means for mounting said members in vertical parallel relationship, said groups being in vertical alignment and closely adjacent each other,

(h) one of said groups of air-guiding members having the air-guiding members thereof spaced in the direction of traffic flow through said doorway and being inclined relative to said direction of traffic flow to cause air issuing from the upper part of said air discharge opening to incline outwardly into the area external of said freezer room,

(i) a second of said groups of air-guiding members thereof spaced in the direction of tralfic flow through said doorway and being inclined relative to said direction of traffic flow to cause air issuing from the lower part of said air discharge opening to incline into said freezer room,

(j) a third-;;$ f said groups of air-guiding members having t air-guiding members thereof spaced in the direction of trafiic flow through said doorway and being normal to said direction of traflic flow to cause air issuing from the central part of said air discharge opening to move generally parallel to the plane of said doorway,

(k) whereby said device simultaneously and continuously directs air adjacent the top of said doorway outwardly of said doorway and directs air adjacent the bottom of said doorway inwardly of said doorway,

(l) the air from said upper, central and lower parts of said air discharge opening being directed to move across said doorway and to enter said inlet opening of said air inlet chamber,

(In) the outwardly-inclined air adjacent the upper part of said air discharge chamber applying a longitudinally-directed outwardly-acting component of force which matches and withstands the component of force applied to the air screen by warm air external of said freezer room attempting to enter said freezer room adjacent the upper part of said doorway,

(n) the inwardly-inclined air adjacent the lower part of the air discharge opening applying a longitudinally directed, inwardly-acting component of force which matches and withstands the component of force applied to the air screen by cold air within said freezer room attempting to issue from said freezer room, and

(o) the air from said upper, central and lower parts of said air discharge opening providing an air screen that substantially isolates the atmosphere within said freezer room from the atmosphere external of said freezer room.

4. A device for producing an air screen adjacent the doorway of a freezer room which comprises:

(a) an air discharge chamber adjacent one side of said doorway,

(b) said air discharge chamber having an air discharge opening therein that is deep in the direction of traffic flow through said doorway,

(c) an air inlet chamber adjacent the opposite side of said doorway,

(d) said air inlet chamber having an air inlet opening therein that is deep in the direction of traffic flow through said doorway,

(f) a motor to drive said blower,

(g) groups of air guiding members disposed within said air discharge opening in said air discharge chamber to guide air issuing from said air discharge chamber, each group comprising spaced parallel air guiding members, means for mounting said members in vertical parallel relationship, said groups being in vertical alignment,

(h) one of said groups of air-guiding members having the air-guiding members thereof spaced in the direction of traflic flow through said doorway and being inclined relative to said direction of traffic flow to cause air issuing from the upper part of said air discharge opening to incline outwardly into the area external of said freezer room,

(i) a second of said groups of air-guiding members having the air guiding members thereof spaced in the direction of traffic flow through said doorway and being inclined relative to said direction of trafiic flow to cause air issuing from the lower part of said air discharge opening to incline into said freezer room,

(j) whereby said device simultaneously and continuously directs air adjacent the top of said doorway outwardly of said doorway and directs air adjacent the bottom of said doorway inwardly of said doorway,

(k) the air from said upper and lower parts of said air discharge opening being directed to move across said doorway and to enter said inlet opening of said air inlet chamber,

(1) the outwardly-inclined air adjacent the upper part of said air discharge chamber applying a longitudinally-directed outwardly-acting component of force which matches and withstands the component of force applied to the air screen by warm air external of said freezer room attempting to enter said freezer room adjacent the upper part of said doorway,

(m) the inwardly-inclined air adjacent the lower part of the air discharge opening applying a longitudinallydirected, inwardly-acting component of force which matches and withstands the component of force applied to the air screen by cold air within said freezer room attempting to issue from said freezer room.

5. A device for producing an air screen adjacent the directs air adjacent said second part of said discharge opening inwardly of said doorway, (j) the outwardly-inclined air adjacent said one part doorway of a room, wherein the atmosphere is maintained at a temperature materially difierent from the ambient temperature, which comprises:

(a) an air discharge chamber adjacent one side of said of said air discharge chamber applying a longitudoorway dinally-directed outwardly-acting component of force (b) said air discharge chamber having an air discharge Whlch majches and withstands the component of opening therein that is deep in the direction of traffic force PP to the alr Screen by air external of fl through i doorway, said room attempting to enter said room, (c) an air inlet chamber adjacent the opposite side of the inwardly-inclined adjacent Said Second P said doorway, of the air discharge opening applying a longitudinally- (d) said air inlet chamber having an air inlet opening directed, inwardly-acting component of force which therein that is deep in the direction of traflic flow matches and withstands the component of force through Said w y, applied to the air screen by air within said room (e) a blower that has the inlet thereof connected to attempting to issue f id room said air inlet chamber and that has the outlet thereof (fconnected to said air discharge chamber, References Cited by the Examiner an air discharging assembly disposed within said discharge opening in said air discharge chamber, UNITED STATES PATENTS said air discharging assembly comprising groups of 774,730 11/1904 Van Kannel 98-36 air guiding members, each of said groups comprising FOREIGN PATENTS spaced, parallel a1r guiding members, means for mounting said members in vertical parallel relation- 971,345 1/1959' Germanyship, said groups being in vertical alignment, 481,991 3/ 1938 Great Bfilain' (g) one of said groups of air guiding members having 6 39 9/ 9 Italy.

the air-guiding members thereof spaced in the direction of trafiic flow through said doorway and being OTHER REFERENCES inclined relative to said direction of trafiic flow to German Printed application, Printed 7/ 1960, cause air issuing from a first part of said discharge 1,035,315

opening to incline outwardly into the area external of said room, and

ROBERT A. OLEARY, Primary Examiner.

Claims

2. A DEVICE FOR PRODUCING AN AIR SCREEN ADJACENT THE DOORWAY OF A FREEZER ROOM WHICH COMPRISES: (A) AN AIR DISCHARGE CHAMBER ADJACENT ONE SIDE OF SAID DOORWAY, (B) SAID AIR DISCHARGE CHAMBER HAVING AN AIR DISCHARGE OPENING THEREIN, (C) AN AIR INLET CHAMBER ADJACENT THE OPPOSITE SIDE OF SAID DOORWAY, (D) SAID AIR INLET CHAMBER HAVING AN AIR INLET OPENING THEREIN, (E) A BLOWER THAT HAS THE INLET THEREOF CONNECTED TO SAID AIR INLET CHAMBER AND THAT HAS THE OUTLET THEREOF CONNECTED TO SAID AIR DISCHARGE CHAMBER, AND (F) AN AIR-DISCHARGING ASSEMBLY DISPOSED WITHIN SAID AIR DISCHARGE OPENING IN SAID AIR DISCHARGE CHAMBER TO GUIDE AIR ISSUING FROM SAID AIR DISCHARGE CHAMBER, (G) SAID AIR-DISCHARGING ASSEMBLY CAUSING AIR ISSUING FROM THE UPPER PART OF SAID AIR DISCHARGE OPENING TO INCLINE OUTWARDLY INTO THE AREA EXTERNAL OF SAID FREEZER ROOM, (H) SAID AIR-DISCHARGING ASSEMBLY CAUSING AIR ISSUING FROM THE LOWER PART OF SAID AIR DISCHARGE OPENING TO INCLINE INTO SAID FREEZER ROOM, (I) THE OUTWARDLY-INCLINED AIR ADJACENT THE UPPER PART OF SAID AIR DISCHARGE CHAMBER APPLYING A LONGITUDINALLY-DIRECTED OUTWARDLY-ACTING COMPONENT OF FORCE WHICH MATCHES AND WITHSTANDS THE COMPONENT OF FORCE APPLIED TO THE AIR SCREEN BY WARM AIR EXTERNAL OF SAID FREEZER ROOM ATTEMPTING TO ENTER SAID FREEZER ROOM ADJACENT THE UPPER PART OF SAID DOORWAY, (J) THE INWARDLY-INCLINED AIR ADJACENT THE LOWER PART OF THE AIR DISCHARGE OPENING APPLYING A LONGITUDINALLYDIRECTED, INWARDLY-ACTING COMPONENT OF FORCE WHICH MATCH AND WITHSTANDS THE COMPONENT OF FORCE APPLIED TO THE AIR SCREEN BY COLD AIR WITHIN SAID FREEZER ROOM ATTEMPTING TO ISSUE FROM SAID FREEZER ROOM, (K) PERFORATE MEMBERS MOUNTED IN SAID AIR INLET CHAMBER ADJACENT SAID AIR INLET OPENING, (L) SAID PERFORATE MEMBERS SUBTENDING AN OBTUSE ANGLE HAVING THE APEX THEREOF EXTENDING INTO SAID AIR INLET CHAMBER.