US2241854A - Air conditioned display compartment - Google Patents

Description

y K. w. HALL ETAL, 241,54

AIR CONDITIONED DISPLAY COMPARTMENT Filed May 21, 1938 2 Sheets-Sheet l CONDH'IONINC: *j

APDAQATUS INVENTORS ATTORN EYS May 13, 1941. K. w. HALL ETAL 2924,8541

AIR CONDITIONED DISPLAY COMPARTMENT Filed May 21, 1938 2 Sheets-Sheet 2 KsW/z M/ Aw EQZ m 0 w w 0 BY wi /44% W MM ATTORN EYS Patented May 13, 1941 2.241.854 V AIR. CONDITIONED DISPLAY oom'anrmm'r Keith W. Hall. and Donald W. McCready, Ann Arbor, Mich; said Hall assignor to 'lolco, Inc., Toledo, Ohio, a corporation of Ohio Application May a1, 1938, Serial No. 209,393

4Claims.

The invention relates to air conditioned compartments suitable for the display in retail stores of products of the soil, cigars, and other products that require a humid or refrigerated atmosphere. In the retailing of products that are displayed in bulk it has been found highly desirable that masses of the products be kept fully visible and uninclosed so that customers may handle them. For example, most consumers visit more I than one food store, so that rapidly movin products such as fruit and vegetables-are sold in greatest quantities by the stores that provide the most effective displays. It is universally found that a retailer sells more of such products by displaying them on open racks than by displaying them behind glass, because an urge to buy is fostered by displaying the products out in the open where the customer can reach out and pick them up. Many perishable products, however, suffer rapid deterioration when kept in the open air. Some products must be kept at low temperatures, and other products, such as vegetables, must be surrounded by humid air to prevent them from drying out and thereby losing their freshness.

The principal object of the invention is to provide a display compartment in which products may be openly displayed and yet surrounded by properly conditioned air. More specific objects and advantages are apparent from the description, in which reference is had to accompanying drawings illustrating a preferred embodiment o the invention. I

Fig. I of the drawings is a perspective of an apparatus provided with display compartments.

embodying the invention, with portions of the apparatus broken away to show its interior construction.

Fig. II is a fragmentary vertical section taken on the line IIII of Fig. I.

Fig. III is a fragmentary vertical section taken on the line III-III of Fig. II.

Fig. IV is a fragmentary horizontal section taken on the line IV--IV of Fig. III.

Fig. V is a fragmentary vertical section taken on the line VV of Fig. I.

Fig. VI is a fragmentary section on an inclined plane taken on the line VIVI of Fig. V.

These specific drawings and the specific description which follows merely disclose and illustrate the invention and are not intended to impose limitations upon the claims. 1

When conditioned air is supplied to products on an ordinary open display rack, the eddies and convection currents that normally exist in the room mix with and dilute the conditioned m" and sweep it away from the surface of the products with surprising rapidity, so as to destroy any protection that might be afforded to the products by the conditioned air. In accordance with the invention, products on display are kept surrounded by conditioned air in a display compartment having an access opening, means for directing a stream of air to form a protective curtain that shields the opening, and means for supplying conditioned air to the compartment. Since conditioned air is continuously supplied to the compartment, there is a continuous exhausting of air from the compartment through the access opening. It has been discovered that it is not necessary to supply an excessive quantity of conditioned air in order to protect perishable products in a compartment embodying the invention. When the conditioned air supplied to the compartment has a high moisture content, products in the compartment can be adequately protected without exhausting so much" humid air as to steam up the room. The discharge of a certain amount of conditioned air into the room cannot be avoided, but the volume of air so discharged can be reduced,if desired, by withdrawing from the display compartment and recirculating back to the air conditioning apparatus a portion of the conditioned air supplied to the compartment.

For products requiring a humid atmosphere, the relative humidityin the compartment can be maintained substantially higher than that ordinarily prevailing in the surrounding atmosphere. The air inside the compartment can also be kept at a temperature considerably below the temperature in the room. When refrigerated air is supplied to an ordinary open rack, it is heated up as fast as it is supplied, because the rack is fully exposed. As the refrigerated air becomes warmer in passing among products on the rack, its relative humidity falls rapidly, so that refrigerated air supplied to an ordinary open rack has a particularly severe effect upon products that are easily dehydrated, such as vegetables. A compartment embodying the invention is advantageous in that it prevents refrigerated air that is supplied to the compartment from being heated up while it is still in contact with the products. The conditioned air in the compartment can be kept at the desired low temperature if the conditioned air is supplied at the proper rate, because the entry of atmospheric air into the compartment is substantially prevented.

In the displaying of fruits and vegetables it is possible to obtain quite satisfactory results by simply humidifying the air that is supplied to the compartment. The air supplied to fruits and vegetables should be highly humidified, and

. the cooling which is incident to the humidiflcation may cause a reduction of 5 to 20 degrees Fahrenheit in the temperature of the air. However, air taken into a humidifier cannot be cooled below its wet bulb temperature. Since the wet bulb temperature of the entering air is always higher than its dew point, the temperature to which the air supply is cooled by merely humidifying it is above the dew point of the surrounding atmosphere.

When the only cooling employed is the cooling incident to the humidiflcation of the air supply, therefore, condensation in and around the display compartment does not occur. In the displaying of fruit and vegetables the prevention of condensation is particularly desirable, because produce becomes slimy and discolored when it is kept wet. The attempts that have heretofore been made to protect produce on display by spraying water upon it have failed because of the discoloration and sliming that was produced. The present invention afiords an important advantage in that it makes it possible to protect fruit and vegetables against dehydration without keeping them wet. Humid air that is supplied to the present compartment is preferably 4 I quite free from particles of liquid'water. If parby this excessive handling. In contrast, a display compartment embodying the invention may simply be covered at night or at any other time when the products are not being displayed. While the compartment is covered, the discharge of conditioned air into the atmosphere may be reduced, so that the room will not be steamed up while there is no one entering or leaving through the door and therefore little ventilation. The compartment may be covered by simply throwing a piece of canvas over it.

The protective curtain of air that shields the opening into the present compartment is discharged in the form of a substantially continuous sheet of rapidly moving air. Any eddies or drafts that might cause atmospheric air to enter the compartment are overcome by the air cur-' tain, so that dilution of the conditioned air in the compartment by atmospheric air is inhibited.

The sheet of moving air formingthe curtain is 1 narrowest near the point of discharge, because the sheet 01 moving air tends to become wider and wider as additional air is entrained. In

fact, the air curtain consists not of air moving in a single direction but air moving with considerable turbulence.

When the air curtain is directed across the compartment opening, it entrains air from the compartment on one side and air from the atmostinuous loss of air from tr compartment because of the entraining action of the air curtain. If this loss of air occurs at a rate substantially greater than the rate at which conditioned air is supplied to the compartment, there may be a tendency for atmospheric air to flow into the compartment. Therefore the conditioned air is preferably supplied to the compartment at a rate substantially as great as the loss of air from the compartment caused by the curtain of air. When the curtain of air is so directed that it does not enter the compartment, the temperature or humidity of the air discharged to form the curtain is not material, and the air used for the curtain need not be conditioned. However, it may be convenient to use conditioned air for the curtain if a supply of conditioned air under pressure is available. Even when conditioned air is employed for the curtain, the discharge of conditioned air from a group of compartments providing ample capacity for a store of ordinary size is not suiiicient to cause excessive humidiflcation of the store.

- The drawings show an apparatus that is particularly suitable for displaying fruit and vege tables. The apparatus is made up of several identical sections, each containing two superimposed display compartments, and any desired number of sections may be employed. Fig. I shows a complete section and a portion of each of the twoadjacent sections.

The main supporting members of each section are its two'side' panels III, which rest upon the floor and are tied together at the front by means of a reinforcing bar H. The rear wall 12 of each section is secured to the side panels l0, and has its lower edge turned inward to form a flange I3. Resting upon the flange l3 and the reinforcing bar H is a plate l4 closing the bottom of the section. Upon the plate Il may be placed baskets containing a reserve supply of produce to be displayed. The masses of produce in the display compartments become depleted as the produce is sold. Thus it is desirable to have the reserve supply of produce handy sothat an attractive massive display can be maintained by continuously replenishing the display compartments.

In front of the baskets stored in the lower portion of the section is a removable front panel I 5.

Conditioned air to protect the produce stored inbaskets in the lower portion of the section is supplied from a main air duct l6 through perforations I! in the bottom of the duct. The rear wall I! of the section slopes forward beneath the air duct It to direct any water that drips from the air duct toward a gutter l8 formed in the rear wall l2 (see Fig. II). Perforations. is are formed in the bottom of the gutter l8 to discharge the water into a sloping trough 20 secured to the back of the rear wall l2. troughs 20 of the several sections overlap and are so inclined that the water flows from trough to trough. v'Ihus the trough 20 of only one of the sections needs to be provided with a drain connection, and this trough receives water from all the other troughs.

Fig. IV shows how the sectional ducts l6 are formed into a single continuous air duct. Each of the sections l6 has an outwardly turned flange 2| surrounding each of its ends. It should be noted that the flange 2| is turned upward instead of downward at the bottom of the duct so that it forms a dam to prevent water from flowing from one section to another. A connecting sleeve The sloping 22 telescopes within the adjacent ends of the two sectional ducts I3, and a rubber gasket 23 surrounding the connecting sleeve 22 is compressed and seals the connection when the two adjacent sections are pushed together. A bolt 24 assists in holding the ends of the adjacent sectional ducts together.

At the front of the sections each pair of adjacent side panels I are held apart by means of channel-shaped spacers 25 (see Fig. VI) fiecured to the spacers 25 by means of screws 26 are decorative strips 21 that conceal the edges of the side panels ID. The side panels of each section support a pan 29 which closes in the top of the bottom compartment in which the baskets are stored. Dovetailing with the front edge of the pan 29 is a suitably shaped ledge 29, to the bottom of which is hinged a swinging door 30. In the left-hand section in Fig. I the swinging door 30 is shown in its uppermost position in which it may be held by a suitable catch. The doors 30 in the other two sections in Fig. I are shown in their closed positions.

In front of the main air duct 16 in each section is a distributing chamber 3| through which fiows the air that forms the curtains which protect the display compartments. The top of the distributing chamber 3| is closed by an upper pan 32 similar to the lower pan 28. Immediately below the upper pan 32 is a sheet 33, which with the pan 32 forms a fiat duct for leading the air forward from the distributing chamber 3|. An upper ledge 34, somewhat similar to the lower ledge 29, dovetails with the front edge of the upper pan 32, and the air curtain protecting the upper display compartment is discharged past the front edge of the upper ledge 34 (see Fig. V). The lower wall of the flat air passage is continued by a suitably formed strip 35 dovetailing with the front edge of the sheet 33. The air curtain that protects the lower display compartment is discharged past the front edge of the strip 35.

Closing the flat air passage at its'front end are an upper closure strip 36 and a lower closure strip 31. The upper closure strip is separated from the upper ledge 34 by means of a spacer 38 to form the discharge slot for the upper air curtain. Similarly the lower closure strip 31 is separated from the adjacent strip 35 to form the discharge slot for the lower air curtain. In the construction shown most of the air tends to pass through the lower discharge slot, so that an adjustable plate 39 is provided for partially obstructing the lower discharge slot. If the bolts supporting the adjustable plate 39 are loosened, they may be slid forward or backward in slots provided in the strip 35 to apportion the amounts of air discharged to form the upper and lower air curtains. Y

The total volume of air discharged to form the air curtains is regulated by means of a slidable metering plate 40 (see Fig. II). The metering plate 49 is held against the main duct l6 by means of guides 4|, and it can be shifted by means of a channel-shaped bracket 42 secured to the front of the metering plate and provided with a handle 43, In the operation of the device the handle 43 may be positioned in any one of four notches 44 (see Fig. III). The arrangement of the orifices in the metering plate 40 and the corresponding orifices in the front wall of the main air duct I is such that the metering plate 40 in each of its four positions uncovers a different number of the orifices in the main duct. Fig. III shows the metering plate 40 in its extreme right-hand position. so that all the orifices in the main duct are uncovered. When the metering plate 40 is in its extreme left-hand position, all of the orifices are closed.

As shown in Fig. I, the sheet 33 forms the top of thelower display compartment, and a cover plate 45 forms the top of the upper display compartment. Electric lights may be secured beneath the sheet 33 and the cover plate 45 at a point near the front where they are concealed. Produce in the upper and lower display compartments is supported upon perforated plates 43, the front edges of which rest upon the upper ledge 34 and the lower ledge 29. Atv their rear edges the perforated plates 46 are supported by hooks 41, and hooks are provided at various levels so that the perforated plates can be supported at any desired angle.

Conditioned air is supplied to the display compartments through suitable orifices 43 in the main air ducts I5, and the conditioned air flows upward through each perforated plate and through the bed of produce resting upon the plate. Conditioned air is supplied to the main duct I 6 from any suitable air conditioning apparatus, and the air in the main duct should be kept under a slight pressure which is substantially constant. The volume of conditioned air supplied to the display compartments may then be regulated by employing orifices 48 of the proper size. The orifices 48 offer such a restricted passage for the air that the frictional resistance met by the air as it passes through the orifices is considerably greater than the resistance offered to the air by the perforated plates 46 and the bed of produce thereabove. Thus the orifices 48 meter the flow of air, and the volume of air supplied to a compartment is substantially constantwhether the compartment is filled with produce or empty. The orifices 48 offer so much frictional resistance to the air that variations in the amount of produce in the compartment do not materially change the total resistance that the air must overcome in flowing from the duct it through the bed of produce. Similarly the orifices i'l meter the air that flows into the bottom compartment where the reserve produce is stored in baskets. be supplied to the duct l6 under a sufiicient pressure so that the desired quantity of air fiows through the-orifices. In the illustrated apparatus the orifices meter the flow of air so that it is only necessary to supply the air to the main duct at the proper constant pressure. Any other suitable arrangement for supplying the air at the correct rate may be employed if desired.

The air curtains indicated by arrows in Fig. I

I are directed slightly outward and do not enter the display compartments. They entrain air from the display compartments, and the conditioned air should be supplied to the compart: ments through the orifices 48 at a rate substan-. tially as great as the loss of air from the compartments caused by the air curtains. If the loss of air by entrainment is not made up by supplying suflicient air through the orifices 49, air will tend to enter the compartments from the atmosphere. I

The air flowing through the orifices 48 impinges against baiile strips 49 secured upon posts 50 by means of screws 5|. The sharp deflection of the air that occurs when it strikes the baille strips 49 causes the precipitation of any mist that the air may contain. Moisture dripping from the baflie strips 49 collects in the pans 23 and 32,

Conditioned air must which have upturned rear and side edges 52 (see Figs. II and III) The upturned edges 52 of the pans compress a rubber gasket 53 against the main duct I and the side panels Hi to produce a water-tight joint. An upper drain spout 54 leads the water from the upper pan 32 to the lower pan 28. Water from the lower pan 28 is I led into the trough 20 through a lower drain spout 55, the inlet of which is protected by a drain guard 55.

Each of the display compartments is divided into two parts by means of a partition 51. It should be noted that the front of the section slopes, particularly in its upper part, so that the fronts of the display compartments are inclined backward. The inclined fronts produce maximum visibility of the products in the compartments, making it possible to employ openings in the compartment fronts that are not unduly large.

It should be noted that the conditioned air that is used for the air curtains tends to cool the bottom of the upper display compartment and the top of the lower display compartment. Unconditioned air would form equally effective air curtains, but a duct leading relatively warm air to the slots from which the air curtains are discharged would have to be suitably insulated.

'The rear wall l2 behind the display compartments and the main duct i5 is covered with insulation' 58. It should be noted that the apparatus shown in the drawings is designed to operate at only to 20 degrees below the temperature of the surrounding atmosphere. For lower temperatures additional insulation may be used underneath the cover plate 45, underneath the bottom plate I 4 of the lower compartment, and against the back of the rear wall behind the bottom compartment.

When the door 301s shut, the bottom compartment is completely closed in. The sides of the bottom compartment are formed by the side panels I. A small area at each side of the section just under the main air duct i6 is not covered by the side panels I0 but by a plate 59, secured to the side panels III by means of screws 50. The apparatus may be finished in pol celain enamel or any other suitably resistant finish.

It is recommended that the air supplied to the main ductlli be air that has been withdrawn from the atmosphere and passed through a humidifier without any cooling other than that incident to the humidification. A relative humidity of 90 to 95 per cent is preferable. The

air may be forced upward through each square foot of the perforated plates 46 at a rate of 100 to 250 cubic feet per hour. The air curtains are preferably made up of a discharge of air at about 600 cubic feet per hour per foot of length of the curtains, flowing at a discharge velocity of about When produce in the compartments is not being displayed to customers, a cloth may be thrown over the apparatus to close the display compartments. While 'the compartments are covered with a cloth, the metering plate 40 may be shifted to its extreme left-hand position, and the conditioned air may be supplied to the main duct It at a reduced pressure if desired.

The embodiments of the invention that have been disclosed may be modified to meet various requirements.

Having described our invention, we claim:

1. In an apparatus of the class described, in combination, a display compartment having walls for enclosing a space extending to a substantial height above products displayed therein and having an access opening, means for directing a stream of air to form a protective curtain of air that shields said opening, and means for continuously supplying conditioned air to the compartment, whereby said conditioned air, continuously escapes through said access opening, and the entry of atmospheric air therethrough is inhibited.

2. In an apparatus of the class described, in combination, a display compartment having walls for enclosing a space extending to a substantial height above products displayed therein and having an access opening, means for directing a stream of air to form a protective curtain of air that shields said opening but does not enter the compartment, and means for continuously supplying conditioned air to the compartment at a rate substantially as great as the loss of air from the compartment caused by said curtain of air.

3. In an apparatus of the class described, in combination, a display compartment having walls for enclosing a space extending to a substantial height above products displayed therein and having an opening suflicient for ready access to productsin the compartment through which they are displayed, means for directing a stream of air to form a protective curtain that,

flows substantially across said opening but does not enter the compartment, and means for continuously supplying conditioned air to the compartment, whereby said conditioned air continuously escapes through said access opening, and

the entry of atmospheric air therethrough is inhibited.

4. In an apparatus of the class described, in-

combination, a display compartment having walls for enclosing a space extending to a substantial height above products displayed therein and having an opening suflicient for ready access to products in the compartment through which they are displayed, means for directing a stream of air to form a protective curtain that flows substantially across said opening but does not enter the compartment, and means for continuously supplying conditioned air to the compartment at a rate substantially as great as the loss of air from the compartment caused by said curtain of air.

DONALD W. McCREADY.

KEITH W.. HALL.

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