US3130559A

US3130559A - Multiple jet conditioning cabinet

Info

Publication number: US3130559A
Application number: US110713A
Authority: US
Inventors: Beckwith Sterling
Original assignee: Dual Jet Refrigeration Co
Current assignee: Dual Jet Refrigeration Co
Priority date: 1961-05-17
Filing date: 1961-05-17
Publication date: 1964-04-28
Anticipated expiration: 1981-04-28
Also published as: GB1001403A; CH415704A; DK117155B

Description

April 28, 1964 s. BEcKwl'rH 3,130,559

MULTIPLE JET CONDITIONING CABINET Filed May 17, 1961 2 Sheets-Sheet 1 FIG. Z

m Sterling Eeckwz'z'h April 28, 1964 s. BEcKwlTH 3,130,559

MULTIPLE JET CONDITIONING CABINET Filed May 17, 1961 2 Sheets-Sheet 2 55 FIG. 5

INVENTOR. Steril?? Beckwi/Z WM,

United States Patent Ofice 3,130,559' Patented Apr. 28, 1964 3,i3i,5:79 CNEI'IENNG CABHQET Steiiing jeeckw h, Libertyviiie Township, Ill., assigner, by

rnesrie assignments, to Balai .iet Refrigeration Cornpany, a corporation of Iliinois Fiied May 17, 1961, Ser. No. 110,713 l@ Ciaims. (Cl. 62256) This invention relates to the conditioning of an enclosed space having one side which is open to the atmosphere for yaccess to the interior of the conditioned space Ifor observation of the contents therein or for displacernent of material into and out of said conditioned space.

As used herein, the term conditioning or conditioned space is intended to refer to the maintenance of the space under variously desired conditions, such for example `as under oxidizing conditions, as by the use of oxidizing ygases (oxygen); reducing conditions, as by use of reducing gases (hydrogen); inert conditions, as by use of an inert gas (argon); refrigerated conditions, as by the use of refrigerated air; heating conditions, as by the use of heated air; moist conditions, as by the use of air at high humidity; and dessicating conditions, as by the use of dry `air, etc. The invention will hereinafter be described with reference to the use of the enclosed space as a part of a refrigerated display cabinet for frozen or refrigerated foods whereby the storage Ispace is adapted to be maintained in a refrigerated state having a ternperature at or below freezing. The same concepts for maintenance of the space in a refrigerated state will apply in the maintenance of the space lat Others of the described conditions, as will become apparent from the following.

In the co-pending `application of Hagen et al., Serial No. 54,077, filed September 6, 1960, saine assignee and entitled Refrigerated Display Case, `and in the issued Simons Patent No. 2,862,369, description is made of a refrigerated display cabinet having a storage space with an open side. Loss of 'heat from the storage space through the open side is substantially obviated by passage of a curtain of air continuously across the space from one edge to an opposite edge thereby to blanket the entire opening by the formed curtain.

The air curtain is adapted to be formed of adjacent panels of air with the inner panel corresponding to the condition desired to be maintained within the enclosed space and the outer panel corresponding more closely to the `ambient atmosphere with one or more panels in between, if desired, corresponding to conditions intermediate the inner panel and the outer panel. The inner panel is referred to as the conditioned panel while the louter panels can be referred to as the guard panels. For most efficient practice, it is desirable to recirculate at least the inner panel of conditioned air and one or more of the adjacent guard panels, thereby to conserve on the investment in conditioning required to maintain the space in the desired refrigerated state, or heated state, dry, wet, oxidizing or reducing state.

For example, in the Simons patent, use is made of an air curtain formed of but two panels comprising an inner cold air panel which is refrigerated yand continuously recircn'lated and `an outer ambient `air panel which is cut olf from the cold air par el for return to the atmosphere. On the other hand, in the aforementioned co-pendin'g application of Hagen et tal., illustration is made of an arrangement which makes use of an inner cold air panel and an outer panel both of which `are recirculated through separate systems in the cabinet whereby the outer panel acquires a temperature intermeditate the cold air panel and the `ambient temperature to function as a guard panel which minimizes heat loss lwhile at the same time e hancing `laminar iiow, as will hereinafter be pointed out.

Also (disclosed in the aforementioned vapplication of Hagen et al. is an arrangement wherein the curtain is formed of three recirculating panels in side-by-side relationship further to increase the eiciency of operation from the standpoint of flow characteristics of the yair curtain and heat loss from the conditioned space.

In the aforementioned constructions, description is made yof lan arrangement wherein the nozzles entend across the bottom edge of the opening to direct ythe air panels upwardly across the opening towards the inlets extending across the top side of the opening. Description is also made of 1an yarrangement with the nozzles located across the upper edge of the `opening for causing the air panels to iiow downwardly across the opening to inlets `across the bottom side of the opening. It will be understood that the air nozzles can also be located across one `of the lateral edges of the opening for directing the air panels across the opening towards the inlets in the opposite edge. Because of the more `desirable effect of gravity on the higher `density cold air, it is preferred to iiow the air curtain `downwardly from nozzles across the top to inlets across the bottom and the invention will erein-after be described with reference thereto, but it will be understood that the concepts hereinafter described will also be applicable to other directional ow.

To minimize the investment in power required to `achieve the `desired refrigeration in the inner air panel, it is desirable to minimize the amount of intermixing between the adjacent panels making up the air curtain as the panels travel together across the lopen space. For this purpose, it is desirabie to maximize laminar flow between the `air panels making up the curtain which is continuously moved `across the open space. Various factors inciuding nozzle construction, air speed, directional ow and the like have been found to have material influence on laminar ow.

it is an object of this invention further to `enhance laminar ow of the air panels across the open space by construction of the cabinet to take into consideration another factor found to have considerable inuence on the ow characteristics of the lair panels and on the amount of intermixing that takes place between the panels.

More specifically, it is an object of this invention to produce a cabinet of the type described embodying means within the space to be conditioned which enhances the laminar flow characteristics of the -air panels making up the curtain.

These land other objects and 'advantages of this invention will hereinafter appear and -for purposes of illustration, but not of limitation, embodiments of the invention are shown in the accompmying drawings in which:

FIGURE l is a schematic sectional elevational View of a conditioning chamber embodying the features of this invention;

FiGURE 2 is a sectional elevational View similar to that of FIGURE l showing a modification in the construction of the cabinet;

FIGURE 3 is an enlarged detailed sectional View of the arrangement of nozzles which may be employed in accordance with the practice of this invention in the modication of the cabinet shown in FIGURE l;

FIGURE 4 is a sectional elevational view similar to that of FIGURE 3 showinL7 a further modification in the nozzle construction and arrangement; and

FiGURE 5 is a sectional elevational view similar to that of FIGURE 3 showing the nozzle arrangement as employed in the construction of the cabinet shown in FIG. 2.

In FIGS. 1 and 2 of the drawings, illustration is made of a conditioning device formed or an enclosure having a top wall 12, a back wall 14, a bottom wall 16, side walls (not shown), and a front wall 18'. The front v a wall is formed with an access opening communicating the enclosed space 22 within the housing with the outside atmosphere. The housing rests upon a suitable 'base 274. Y V

Spaced inwardly from the described housing walls and in substantially parallel relationship therewith are inner Walls incluing a top wall 26, back wall 28, bottom Wall 30, front wall 32 and side walls 34, all of which dene the enclosed space 22. The space between the innerrwalls and the outer walls is subdivided in FIG. 1 'by a partitioning Wall 36 to define two

separated passages

38 and 40 which extend substantially continuously about the storage space 22 from the

outlet openings

39 and 41 4across one edge of the opening 20 to

inlets

42 and 44 across the opposite edge of the opening 20.

When used as a refrigerated display case, the inner passage 38 is provided with refrigeration coils 46 through which a suitable refrigerant is circulated for indirect heat exchange with the air travelling through the passage 38 for the refrigeration thereof. While the refrigeration means 46 is illustrated as being located centrally within the passage 38, it will be understood that the refrigeration means may be disposed in other parts of the passage 3S but preferably in the direction towards the inlet 42. Located between the refrigeration means 46 and the inlet 42 is an air circulating means such as a fan or blower 48 which induces the ow of a stream of air through the passage 33 from the inlet 42 to the outlet 39 and, in accordance with the concepts of this invention, from the outlet 39, across the open space to the inlet 42 for recirculation of the cold air stream.

Similarly located within the outer passage 40 is another air circulating means, such as a fan or blower 50, for inducing the ow of an air stream through the passage 40 from the inlet 44 to the outlet 41 and then, in accordance with the concepts of this invention, from the outlet 41 across the open space 20 to the inlet 44 for recirculation of the guard jet.

The outlet 39 of the inner passage 38 is in the form of a nozzle 52, such as a vaned or honeycomb section, preferably dimensioned to have a length greater than 1 inch, but less than about 6 inches, for directional control of air flow, and which extends continuously across the top side of the access opening 20 in the front Wall of the cabinet. Similarly, the outlet 41 for the outer passage 40 is in the form of a nozzle 54 of a vaned or honeycomb section which also extends substantially continuously across the top side of the access opening 20 along the notzhzle 52 and in substantially parallel relationship therew1v The streams of air issuing from the

outlets

39 and 41 form continuous inner and outer air panels 56 and 58 respectively which extend across the access opening 20 from the

outlets

39 and 41 to the

inlets

42 and 44.

Y Both of the inlets can be provided with screening members 60 to prevent entrainment of solid material, insects and the like into the air streams.

From the foregoing brief description of the basic construction of the conditioning cabinet, it will be apparent that there is provided an inner cold air panel 56 and an outerpwarmer air panel 58 which is intermediate the temperature of the cold air panel and the ambient air. The guard panel S8, at intermediate temperature, operates to guard the cold air from the heat of the atmosphere and to minimize the loss of cold air into the atmosphere since air entrained from the guard panel into the cold air panel will be at considerably lower temperature than the air from the atmosphere which otherwise would be the admixed component. Further to minimize heat loss into `the cold air recirculated through the passage 3S, it is desirable though not essential that the partitioning wall 36 and the outer walls of the cabinet be provided With suitable insulation, as designated by the numeral 62.

The arrangement for recirculation of one or more guard jets in combination with the cold or conditioned air jet to form an air curtain extending across the access opening also operates to enhance the laminar ilow characteristics of the air panels whereby a minimum amount of intermixing of air in the panels occurs.

Thus by way of still further modification, instead of making use of a single guard jet, additional guard jets may be provided whereby the air panels extending across the access opening 20 will correspond to the number of such jets. In the modification illustrated in FIG. 2, an additional partition is provided in the cabinet to make available a third passage 70 provided with its own fan or blower 72 for lthe recirculation of an outer air stream Vthrough the passage 70 from an inlet 74 to an outlet 76 and, in accordance with the concepts of this invention, from the outlet 76 across the open space to the inlet 74. Thus the air curtain is provided with a third air panel 78 which is located outwardly adjacent to the air panels S and 56. For best practice in maintaining desirable laminar now characteristics between the panels projected across the access opening, it is desirable to provide for air velocities within the range of 50 to 1,000 feet per minute and preefrably within the range of to 400 feet per minute.

As previously indicated, it is desirable to minimize intermixing `of the `air panels making up the air curtain otherwise a substantial amount of the conditioned or cold airV will find its -way into .the outer guard .panels and into the atmosphere thereby to require a greater investment in Irefrigeration or other conditioning for maintenance Vof the desired conditions or refrigerated state within the otherfwise enclosed space 22. lntermixing is believed to be an indirect function of the extent of laminar flow between the lair panels making up the air curtain whereby improvements in the laminar flow `characteristics of the air curtain during travel across the open space will reduce the amount of intermixing taking place between the air panels.

There are a number `of factors which have been found to influence laminar flow, including uniformity of air velocity of the air streams making up the adjacent panels. Another factor faced by the invention described in my co-pending `application tiled concurrently herewith and entitled Conditioned Storage Cabinet resides in the means extending crosswise of the air curtain within the` conditioned space to minimize bending of the air curtain into the conditioned space whereby conflicting lair currents are set up which interrupt the laminar flow of the air curtain to introduce turbulence with corresponding increase in intermixing between panels.

Another factor found to have a noticeable effect on the laminar ow characteristics `of the air curtain resides in the number of 'air panels or guard jets employed in comhina-tion with the inner panel of conditioned air. This inuence can perhaps best be illustrated by the effect which is noticed when one or more of the air panels are terminated in sequence. F or example, in ya system making use of two recirculating guard jets in combination with the inner panel yof conditioned air projected at normal `speed across an -access opening of about 18 to 30` inches, yas illustrated in FIG. 2, turbulence of a slight degree will be found to occur as the air curtain :approaches the inlets. When the outer guard jet 7S is discontinued, the amount of turbulence will noticeably increase and the point of initiation of turbulence will more closely approach the outlets. Fur-ther elimination of the guard panel 58 will result `in still greater turbulence initiated at a still closer point from the outlet whereby substantially greater amounts of -intermixing between panels Will occur.

This -invention is :addressed to la still further concept for improving the laminar flow characteristics of lthe air curtain thereby to reduce intermixing and further to increase the eliiciency of operation of the conditioning system.

Briey described, it has been found that the laminar ilow characteristics of the air panels making up the lair curtain -is noticeably improved, with corresponding reduction in intermixing, when the air panels making up the air curtain 4are merged to -iio-w across the open space 20 without any spaced relationship between panels. For this purpose, one of the concepts `of this invention is to arrange the nozzles -so that the `outlet nozzles terminate with the adjacent edges in side-.by-side relationship with a minimum of Wall space in between and preferably without any projection extending outwardly beyond the nozzles to extend linto the space between panels. It has been found that when a substantial spaced relationship exists between the adjacent edges of the nozzles, a dead space is formed which tends to embody the characteristics of an aspirated space Iwhereby forces exist to cause deviation in lthe adjacent portions of the air panels. deviations or inuences operate noticeably to reduce laminar flow characteristics `of the air panels with corresponding increase in turbulence and intermixing of air between the adjacent panels.

Another important concept of this invention resides in the further arrangement of the outlet nozzles 52, 54 and/ or 76 at slightly converging angles to cause mergence of the air panels .almost immediately upon issuance from the nozzles thereby to minimize the existence of a spaced relationship between panels. The angle of convergence need be only a few degrees but not more than about It is preferred to construct the nozzles for an angle of convergence within a range of from 5 to 15 therebetween and preferably with the nozzles arranged for issuance of the panels in side-by-side relationship with practically no space in between.

The described concept of angle of convergence and minimum wall space between adjacent edges of adjacent nozzles has application in a two air panel system of the type shown in FIGURE l and illustrated in FIGURE 3 or a multiple air panel system of the type shown in FIG- URE 2 and illustrated in FIGURE 5. It has application also independently of the direction of travel of the air panels that is from top to bottom across the open space, or from bottom to top, or Ifrom side to side across the open space or whether the inner conditioned panel is a cold air panel for maintaining .a refrigerated state, a hot fair panel for maintaining a heated state, a dry air panel for maintaining a dessicated state, a hydrogen enriched -air panel for providing a yreducing atmosphere, an oxygen enriched air panel `for maintaining an oxidizing state or the like within the conditioned space 22.

With particular reference to the arrangement wherein the inner panel is a cold air panel for maintaining a refrigerated state .within the cabinet for use in the display and storage of frozen foods, a further important concept of this invention resides in the construction, as illustrated in FIGURE 4, wherein a thermal insulating barrier -Si is permitted to be provided between the

angled nozzles

52 and 54 `forming the cold `air panel and the adjacent guard panel. In the absence of such thermal insulating member `8l), =it has been found that the cold from the adjacent cold air stream will elfect refrigeration of at least the inner portions of the guard stream and the elements associated therewith to cause possible condensation of moisture in the guard air stream during passage through the adjacent inner portions of the guard nozzles with subsequent possible freezing or frost formation to block the openings of the nozzle. This not only results in interference with the desired guiding relationship intended to be achieved by the vaned nozzles for directional flow of the air stream from the nozzles but it also introduces an undesirable spaced relationship between the ladjacent edges of the adjacent panels to introduce lfactors increasing turbulence and decreasing laminar flow, as previously described.

Further to protect the guard jet from frost formation in the portions of the nozzle adjacent the cold air panel, it is the preferred practice of this invention to construct the nozzles with a heating element 82 lining the outside wall of the nozzle with the heating element 82 preferably being in the'form of resistance wires lying adjacent the outer surface of the nozzle so 'as to be out of the path of the air stream liowing therethrough. As illustrated in FIG. 4, it is desirable to extend the heating element beyond the ingoing side of the nozzle to preheat the adjacent portions of the air stream before engagement with the nozzle thereby :to militate against separation of snowsr on the ingoing side of the nozzle upon being contacted with the relatively swiftly moving stream of air making up the guard jet.

It will be apparent from the foregoing description that I have provided means for use in a `conditioning cabinet of the type described adapted to enhance the laminar flow characteristics of air panels projected across the open space whereby a minimum amount of intermixing between air panels will occur during the normal or steady operation of the device. Improvement in the laminar flow characteristics by immediate convergence of the air panels into a single air curtain operates to extend the length of the stream maintaining laminar ow characteristics whereby a minimum amount of intermixing occurs. This, as a result, minimizes the amount of conditioning required to be introduced into the inner panel for maintaining the desired condition lwithin the otherwise enclosed space.

`It will be understood 'that changes may be .made in the details of construction, arrangement and operation Without departing from the spirit of the invention, especially as defined in the `following claims.

I claim:

l. In a cabinet yhaving an access opening in one side communicating a storage space within the cabinet with the ambient atmosphere, at least two outlet nozzle extending continuously across one side of the -access opening and corresponding inlet members extending across the opposite side of the opening, and means for continuously circulating panels of air from the outlet nozzles of the inlets across the opening with the inner panel being a conditioned air panel, `the improvement which comprises angling the outlet nozzles for convergence in the direction towards each other at the outlet end portion to merge the air panels issuing from the nozzles into a continuous air curtain owing across the access opening with the conditi-oned air panel located inwardly in the yair curtain.

2. A cabinet as claimed in claim l, in which the outlet nozzles are positioned at an angle of convergence with the range of 3 to 30.

3. A cabinet as claimed in claim l, in which the angle of convergence between adjacent outlet nozzles is within the range of 5 to 15.

4. In a display cabinet having an access opening in one side communicating a storage space /within the cabinet with the ambient atmosphere, at least two outlet nozzles extending continuously across the one side of the access opening and corresponding inlet members extending across the opposite side of the opening, and means for continuously circulating panels of air from 'the respective outlet nozzles to the inlet members across the access opening with the inner panel being a conditioned air panel, the improvement which comprises positioning the outlet nozzles in -side-by-side parallel relationship across the one side of the access opening with a thin Iwall separating the adjacent edges at the outlet end of the nozzles to .avoid tlie formation of a dead space between the air panels issuing from the nozzles, and positioning the nozzles at an angle converging inthe direction towards each other, and positioning adjacent nozzles at an angle of convergence to merge the air panels issuing from the nozzles into a continuous air curtain flowing across the access opening with the conditioned air panel located inwardly in the curtain.

5. In a refrigerated display cabinet having an access opening in one side communicating a storage space adapted to be refrigerated within the cabinet with the ambient atmosphere, at least two outlet nozzles extending conresponding inlet members extending across the opposite side of the opening, means for continuously circulating panels of air from the "outlet nozzles to the inlet members `across the access opening With the inner panel being a cold air panel, and means recirculating the air panels from the inlet members to the outlet nozzles, the improvement which comprises positioning the outlet nozzles in side-by-side parallel relationship across the one side of the access opening with .a minimum of spaced relationship between the `adjacent edges at the outlet end to avoid the formation of la dead air space between the air panels issuing from the nozzles 'and angling the outlet nozzles to converge in the direction towards each other for mergence of the air panels into a continuous air curtain flowing `across the access opening with the cold `air panel located inwardly of the remainder.

6. A refrigerated cabinet 'as Claimed in claim 5, in which the outlet nozzles extend across the top of the outlet of the access opening for circulation of the air panels downwardly `across the open space.

7. A refrigerated cabinet `as claimed in claim 5, which includes insulation between the inner cold air nozzle and the `adjacent nozzle to provide a barrier against the transfer oficold yfrom the cold `air nozzle to the air .passi-A ing through the adjacent nozzle.

8. A refrigerated cabinet as claimed in claim 7, which* includes a heating element alongside the adjac'emmair nozzle `between the `adjacent air. nozzle and the cold lair nozzle.

9. A refrigerated display cabinet Vas claimed in claim 5, in which the outlet nozzles comprises yaned sections having a length greater than labout l inch, .and a thermal insulating barrier positioned between the 'angled cold air nozzle and the outlet nozzle adjacent thereto.

l0. A refrigerated cabinet as claimed in claim 9, which includes Ia heating element alongside ythe adjacent nozzle between the insulation `and said adjacent nozzle.

References Cited in the le of this patent UNITED STATES PATENTS 983,877 Cummings Feb. 14, 1911 2,794,325 Shearer .Tune 4, 1957 2,836,039 Weber May 27, 1958 3,063,252 Lamb Nov. 13, 1962 3,063,256 Lamb Nov. 13, 1962 Corrected Disclaimer 3,130,559-Sterling Beckwith, Libertyville Township, Ill. MULTIPLE J ET CONDITIGNING CABINET. Patent dated Apr. 28, 1964. Disclaimer filed Apr. l0, 197 2, by the assignee, Kysor Industrial Corporation. Hereby enters this disclaimer to claims 1, 2, 5 and 6 of said patent.

[This disclaimer supersedes disclaimer issued June 6, 1972.]

Claims

1. IN A CABINET HAVING AN ACCESS OPENING IN ONE SIDE COMMUNICATING A STORAGE SPACE WITHIN THE CABINET WITH THE AMBIENT ATMOSPHERE, AT LEAST TWO OUTLET NOZZLE EXTENDING CONTINUOUSLY ACROSS ONE SIDE OF THE ACCESS OPENING AND CORRESPONDING INLET MEMBERS EXTENDING ACROSS THE OPPOSITE SIDE OF THE OPENING, AND MEANS FOR CONTINUOUSLY CIRCULATING PANELS OF AIR FROM THE OUTLET NOZZLES OF THE INLETS ACROSS THE OPENING WITH THE INNER PANEL BEING A CONDITIONED AIR PANEL, THE IMPROVEMENT WHICH COMPRISES ANGLING THE OUTLET NOZZLES FOR CONVERGENCE IN THE DIRECTION TOWARDS EACH OTHER AT THE OUTLET END PORTION TO MERGE THE AIR PANELS ISSUING FROM THE NOZZLES INTO A CONTINUOUS