Refrigerated merchandiser display case

• US 4,369,632 A
• Filed: 04/18/1980
• Issued: 01/25/1983
• Est. Priority Date: 12/07/1979
• Status: Expired due to Term

• Current Assignee: Tyler Refrigeration Corp. (Carrier Global Corporation)
• Original Assignee: Tyler Refrigeration Corp. (Carrier Global Corporation)
• Inventors: Abraham, Fayez F.
• Primary Examiner(s): King, Lloyd L.
• Application Number:
  US06/141,360
• Time in Patent Office: 1,012 Days
• Field of Search: 62/255, 62/256, 62/82, 62/408, 62/282, 62/151, 312/116, 312/236
• US Class Current: 62/82
• CPC Class Codes: A47F 3/0408 with forced air circulation
• CPC Class Codes: F25D 21/125 the hot fluid being ambient air
• CPC Class Codes: F25D 2317/0684 the fans allowing rotation in reverse direction

Abstract

An improved refrigerated merchandiser cabinet for food products storage and displaying which is equipped with both transparent barrier doors and an air defrost system to improve the energy efficiency. The barrier doors are openable for product entry and customer usage as well as by an air defrost system which creates a gap between the barrier door and the covered access opening to permit flow-through of ambient air for use during the defrost cycle. Operation of the refrigerated cabinet with either a single or multiple air bands during a refrigeration cycle is provided for. During the defrost cycle a number of ambient air flow pattern can be employed, including the use of an auxiliary air fan. Reversal of the air band flow pattern during a defrost cycle is provided for. The method of operating the improved refrigeration display cabinet is also included.

Claims

1. In a display cabinet having refrigeration means and a display space therein, aperture means in at least one wall of said cabinet for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting products to be moved into and out of said display space, air moving means for circulating at least one air band within said cabinet and into contact with said refrigeration means during a refrigeration cycle, covering means for said aperture means including a barrier door for substantially covering said access opening, and said refrigeration means including a low temperature element;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening, said air defrost means causing said air moving means to pass ambient air through said cabinet and through the gap between said barrier door and said access opening during a defrost cycle to bring the ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet, means for providing a plurality of air bands for circulation within said cabinet during a refrigeration cycle, and, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle.

2. The improvement according to claim 1, wherein said aperture means includes an air passage port in a wall of said cabinet, and wherein said air moving means passes ambient air through said cabinet by moving air through said air passage port and through the gap between said carrier door and said access opening during a defrost cycle.

3. The improvement according to claim 1, wherein said aperture means includes an air passage port in a wall of said cabinet, and wherein said air moving means draws ambient air into said cabinet through said air passage port and ejects defrost ambient air through the gap between said barrier door and said access opening during a defrost cycle.

4. The improvement according to claim 1, wherein during a defrost cycle said air defrost means creates the gap between said barrier door and said access opening and causes said air moving means to draw ambient air into said cabinet through a first portion of said gap and to eject the defrost ambient air through a second portion of said gap.

5. The improvement according to claim 1, wherein during a defrost cycle said air defrost means selectively creates the gap between said barrier door and said access opening and permits said barrier door to substantially cover said access opening during a refrigeration cycle to thereby conserve operating energy for said display cabinet.

6. The improvement according to claim 1, wherein said air moving means for circulating at least one air band within said cabinet comprises a first air circulation means for propelling a primary refrigerated air band, and a second air circulation means for selectively propelling a secondary air guard band in the same direction as said primary air band during a refrigeration cycle and for drawing ambient air into said secondary air band and then propelling the ambient air through said cabinet in a reverse direction to said refrigerated air band and into contact with said low temperature element during a defrost cycle.

7. The improvement according to claim 6, wherein said cabinet includes an air guidance means for deflecting at least a portion of said secondary air guard band into said primary air band during a defrost cycle.

8. The improvement according to claim 7, wherein said guidance means deflects substantially all of said secondary air band into said primary air band.

9. The improvement according to claim 6, including a primary air conduit arranged inside said cabinet about said display space for containing said primary refrigerated air band and a secondary air conduit arranged within said cabinet adjacent to said primary air conduit for containing said secondary air guard band, said secondary air circulation means propelling said secondary air band in the same direction as said primary air band during a refrigeration cycle to provide a guard function for said primary band and in the opposite direction from the flow of said primary air band during a defrost cycle of operation.

10. The improvement according to claim 9, wherein said cabinet includes an air guidance means for deflecting at least a portion of the air flow in said secondary air guard band into said primary air conduit during a defrost cycle when said secondary air band is propelled in the opposite direction to the flow direction of said primary air band.

11. The improvement according to claim 6, wherein said second air circulation means includes at least one two-directional air fan for propelling said secondary air band in either direction.

12. The improvement according to claim 6, wherein said control means contains means for reducing the refrigeration function of said refrigeration means at the beginning of a defrost cycle, causing said air defrost means to create a gap between said barrier door and said access opening, and reversing the flow of said secondary air band from the direction of flow of said primary refrigeration air band during a refrigeration cycle to the opposite direction and drawing ambient air through the gap into said cabinet and moving said ambient air over said low temperature element of said refrigeration means to defrost the same and to thereafter eject the defrost ambient air through said aperture means.

13. The improvement according to claim 1, wherein said air moving means includes an auxiliary air circulation means for increasing ambient air inflow into said display cabinet and for commingling the ambient air with said air band during a defrost cycle.

18. The improvement according to claim 1, wherein lighting means is included in said cabinet for illuminating said display case.

23. The improvement according to claim 1, including a primary air conduit arranged inside said cabinet about said display space for containing a primary refrigerated air band during a refrigeration cycle of operation, and a secondary air conduit arranged within said cabinet adjacent to a substantial portion of said primary air conduit, and said secondary air conduit connected at an inlet end thereof to said primary air conduit, said primary and said secondary conduits being separate along the lengths thereof from said secondary conduit inlet and to the outlet end thereof, and said cabinet including a common conduit inlet chamber for said primary refrigerated air band and a secondary air band flowing in said secondary air conduit.

24. The improvement according to claim 23, wherein during a refrigeration cycle of operation said air moving means propels said primary air band within said primary air conduit and through said common conduit inlet portion and propels said secondary air band within said secondary air conduit and through said common conduit inlet chamber, and wherein during a defrost cycle of operation said air defrost means causes said air moving means to reverse the flow direction of said primary and secondary air bands and to draw ambient air into said cabinet and into contact with said low temperature element for defrosting.

14. In a display cabinet having refrigeration means and a display space therein, aperture means in at least one wall of said cabinet for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting products to be moved into and out of said display space, air moving means for circulating at least one air band within said cabinet and into contact with said refrigeration means during a refrigeration cycle, covering means for said aperture means including a barrier door for substantially covering said access opening, and said refrigeration means including a low temperature element;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening, said air defrost means causing said air moving means to pass ambient air through said cabinet and through the gap between said barrier door and said access opening during a defrost cycle to bring the ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle, and said air moving means comprising a first air circulation means for propelling a primary refrigerated air band during a refrigeration cycle and a secondary air circulation means for propelling a secondary air guard band in the same direction as said primary air band during a refrigeration cycle, said air defrost means selectively reversing the direction of flow of said primary air band and terminating operation of said refrigeration means and of said secondary air circulation means during a defrost cycle to prevent flow of said secondary air guard band whereby ambient air is passed through said cabinet by said primary air band.

15. The improvement according to claim 14 wherein said secondary air circulation means is prevented from propelling said secondary air band during portions of the refrigeration cycle in which said barrier door is not opened.

16. The improvement according to claims 6 or 14 wherein said control means contains sensing means for detecting the opening of said barrier door and wherein said control means operates said secondary air circulation means for propelling said secondary air band in the same direction as said primary refrigerated air band selectively in response to the opening of said barrier door during a refrigeration cycle.

17. The improvement according to claim 14 wherein said control means includes means for sensing the refrigeration condition within said display space and means for selectively operating said air moving means to propel said secondary air band in the same direction as said primary refrigerated air band opening upon the refrigeration condition sensed.

20. The improvement according to claim 14, wherein during a defrost cycle of operation said first air circulation means is caused to reverse the flow of said primary air band from the direction of flow during a refrigeration cycle of operation and to discharge defrost ambient air through a portion of said aperture means other than said access opening.

21. The improvement according to claim 14, wherein during a defrost cycle of operation defrost ambient air is discharged from said cabinet through the gap between said barrier door and said access opening.

22. The improvement according to claim 14, wherein said air moving means includes an auxiliary air circulation means for increasing ambient air inflow into said display cabinet and for comingling the ambient air with said primary air band during a defrost cycle of operation in which the direction of air flow is maintained the same as in a refrigeration cycle, and wherein the defrost ambient air is discharged from said cabinet through the gap between said barrier door and said access opening.

19. In a display cabinet having refrigeration means and a display space therein, aperture means in at least one wall of said cabinet for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting products to be moved into and out of said display space, air moving means for circulating at least one air band within said cabinet and into contact with said refrigeration means during a refrigeration cycle, covering means for said aperture means including a barrier door for substantially covering said access opening, and said refrigeration means including a low temperature element;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening, said air defrost means causing said air moving means to pass ambient air through said cabinet and through the gap between said barrier door and said access opening during a defrost cycle to bring the ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle, said air moving means comprising a first air circulation means for selectively propelling a primary refrigerated air band within a primary conduit contained in said cabinet and a second air circulation means for selectively propelling a second air guard band within a secondary conduit contained in said cabinet in the same direction as said primary air band during a refrigeration cycle, said air defrost means during a defrost cycle of operation terminating operation of said second air circulation means and causing said primary air band to draw ambient air from outside said cabinet and to contact said low temperature element with said primary air band containing the ambinet air.

25. In a display cabinet having refrigeration means and a display space therein, aperture means in at least one wall of said cabinet for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting products to be moved into and out of said display space, air moving means for circulating at least one air band within said cabinet and into contact with said refrigeration means during a refrigeration cycle, covering means for said aperture means including a plurality of barrier doors attached to said display cabinet for substantially covering said access opening, and said refrigeration means including a low temperature element;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening, said defrost means causing said air moving means to pass ambient air through said cabinet and through the gap between said barrier door and said access opening during a defrost cycle to bring the ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet, and said air defrost means selectively creating a gap between at least alternate doors of said plurality of doors and said access opening during a defrost cycle of operation, and, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle.

26. The improvement according to claim 25, wherein said air defrost means creates a gap between substantially all of said barrier doors and said access opening simultaneously.

27. The improvement according to claim 25, wherein said barrier doors contain therein a transparent material viewing port.

28. The improvement according to claim 25, wherein said air defrost means comprises a series of door operating mechanisms arranged for individually and selectively creating a gap between each of said barrier doors and said access opening during a defrost cycle.

29. The improvement according to claim 25, wherein said air defrost means comprises a door operating mechanism for selectively creating a gap between at least alternate doors in a series of said barrier doors and said access opening.

30. A display cabinet having a refrigeration means and a display space therein comprising:

a cabinet having top, bottom, and end and side walls and having aperture means in at least one wall thereof for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting access to said display space;

covering means for said aperture means including a barrier door for substantially covering said access opening, said door being movable for enabling access to products within said display space;

a primary air conduit arranged about said display space and having an outlet opening and an inlet opening at opposing ends thereof, said outlet opening and said inlet opening being arranged in aerodynamic alignment;

a primary air band contained within said primary air conduit which upon leaving said outlet opening will be directed toward and received by said inlet opening to form an air curtain across said access opening along a path inside of said barrier door;

a secondary air conduit arranged about said primary air conduit and extending along said top, bottom, rear and side walls of said cabinet;

a secondary air band contained within said secondary air conduit;

said refrigeration means including a low temperature element;

air moving means for circulating said primary and said secondary air bands within said air conduits within said air conduits and for moving said primary air band into contact with said low temperature element during a refrigeration cycle of operation;

air defrost means for selectively creating a gap between said barrier door and said access opening;

said air defrost means causing said air moving means to pass ambient air through said cabinet and through said aperture means during a defrost cycle of operation to bring said ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet; and

, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle.

31. A display cabinet according to claim 30, wherein said aperture means includes an air passage port in a wall of said cabinet, and wherein said air moving means passes ambient air through said cabinet by moving air through said air passage port and through the gap between said barrier door and said access opening during a defrost cycle.

32. A display cabinet according to claim 30, wherein said aperture means includes an air passage port in a wall of said cabinet, and wherein said air moving means draws ambient air into said cabinet through said air passage port and ejects the defrost ambient air through the gap between said barrier door and said access opening during a deforst cycle.

33. A display cabinet according to claim 30, wherein during a defrost cycle said air means creates the gap between said barrier door and said access opening and said air moving means draws ambient air into said cabinet through a first portion of the gap and ejects the defrost ambient air through a second portion of the gap.

34. A display cabinet according to claim 30, wherein said air defrost means selectively creates a gap of preset distance between said barrier door and said access opening.

36. A display cabinet according to claims 34 and 35, wherein the gap distance between said barrier door and said access opening is approximately 1 to 7 inches.

43. A display cabinet according to claim 30, including a primary air conduit arranged inside said cabinet about said display space for containing a primary refrigerated air band during a refrigeration cycle of operation, and a secondary air conduit arranged within said cabinet adjacent to a substantial portion of said primary air conduit, and said secondary air conduit connected at an inlet end thereof to said primary air conduit, said primary and said secondary conduits being separate along the length thereof and said secondary conduit inlet end to the outlet end thereof, and said cabinet including a common conduit inlet chamber for said primary refrigerated air band and said secondary air band flowing in said secondary air conduit.

44. A display cabinet according to claim 43, wherein during a refrigeration cycle of operation said air moving means propels said primary air band within said primary band conduit and through said common conduit inlet chamber and propels said secondary air band within said secondary air conduit and through said common conduit inlet chamber, and wherein during a defrost cycle of operation said air defrost means causes said air moving means to reverse the flow direction of said primary and said secondary air bands and to draw ambient air into said cabinet and into contact with said low temperature element for defrosting.

53. A display cabinet according to claim 30, wherein said control means includes means for sensing the refrigeration condition within said display space and means for selectively operating said air moving means to propel said secondary air band in the same direction as said primary refrigerated air band depending upon the refrigeration condition sensed.

54. A display cabinet according to claim 30, wherein said barrier door contains therein a transparent material viewing port.

35. A display cabinet having a refrigeration means and a display space therein comprising:

a cabinet having top, bottom, end and side walls and having aperture means in at least one wall thereof for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting access to said display space;

covering means for said aperture means including a barrier door for substantially covering said access opening, said door being movable for enabling access to products within said display space;

at least one air conduit extending along said top, bottom, rear and side walls about said display space and having an outlet opening and an inlet opening at opposing ends thereof, said outlet opening and said inlet opening being arranged in aerodynamic alignment;

an air band contained within said air conduit which upon leaving said outlet opening will be directed toward and received by said inlet opening to form an air curtain across said access opening along a path inside of said barrier door;

said refrigeration means including a low temperature element;

air moving means for circulating said air band within said air conduit for moving said air band into contact with said low temperature element during a refrigeration cycle of operation;

air defrost means for selectively creating a gap of variable distance between said barrier door and said access opening depending upon the amount of frost accumulation on said refrigeration means and the time period for the defrost cycle;

said air defrost means causing said air moving means to pass ambient air through said cabinet and through said aperture means during the defrost cycle of operation to bring said ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient from said cabinet; and

, control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle.

37. A display cabinet having a refrigeration means and a display space therein comprising:

a cabinet having top, bottom, end and side walls and having aperture means in at least one wall thereof for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting access to said display space;

covering means for said aperture means including a barrier door for substantially covering said access opening, said door being movable for enabling access to products within said display space;

at least one air conduit extending along said top, bottom, rear and side walls about said display space and having an outlet opening and an inlet opening at opposing ends thereof, said outlet opening and said inlet opening being arranged in aerodynamic alignment;

an air band contained within said air conduit which upon leaving said outlet opening will be directed toward and received by said inlet opening to form an air curtain across said access opening along a path inside of said barrier door;

said refrigeration means including a low temperature element;

air moving means for circulating said air band within said air conduit and moving said air band into contact with said low temperature element during a refrigeration cycle of operation;

air defrost means for selectively creating a gap between said barrier door and said access opening;

said air defrost means causing said air moving means to pass ambient air through said cabinet and through said aperture means during a defrost cycle of operation to bring said ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet;

control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle, said air conduit comprising a primary air conduit containing a primary refrigerated air band and a secondary air conduit extending about a substantial portion of said primary air conduit and having a secondary conduit outlet opening and an inlet opening at opposite ends thereof, said secondary conduit outlet opening and said inlet opening being arranged in aerodynamic alignment;

a secondary air band contained within said secondary air conduit which upon leaving said outlet opening is directed toward and received by said inlet opening to form a secondary air guard curtain across said access opening along a path outside of said primary air band and inside of said barrier door during the refrigeration cycle.

38. A display cabinet according to claim 37, wherein said air moving means includes at least one two-directional air fan located in said secondary air conduit, said air moving means selectively propels said secondary air band within said secondary air conduit in the same direction as said primary air band during a refrigeration cycle and in a reverse direction during a defrost cycle, an air guidance means is located in said cabinet for diverting at least a portion of said secondary air band into said primary air conduit during a defrost cycle, said air defrost means functions to propel said air bands during a defrost cycle to draw ambient air into said cabinet through said aperture means, to co-mingle the ambient air with said secondary air band, to propel said secondary air band through said secondary conduit then into said primary air conduit inlet prior to movement across said refrigeration means for defrosting said low temperature element and ejecting the defrost air from said display cabinet through the gap created between said barrier door and said access opening.

39. A display cabinet according to claim 37, wherein an airflow guidance means is provided to communicate said secondary air conduit inlet with said primary air conduit for deflecting at least a portion of said secondary air band from said secondary conduit into said primary conduit during a defrost cycle.

49. A display cabinet according to claim 37, wherein said air moving means includes an auxiliary air circulation means for increasing ambient air in-flow into said display cabinet and for commingling the ambient air with said primary air band during a defrost cycle.

50. A display cabinet according to claim 37, wherein said air moving means is prevented from propelling said secondary air band during a defrost cycle of operation.

51. A display cabinet according to claim 37, wherein said air moving means propels said secondary air band only during portions of the refrigeration cycle in which said barrier door is open.

52. A display cabinet according to claim 51, wherein said control means contains sensing means for detecting the opening of said barrier door and wherein said control means operates said air moving means for propelling said secondary air band in the same direction as said primary refrigerated air band selectively in response to the opening of said barrier door in a refrigeration cycle.

40. A display cabinet having a refrigeration means and a display space therein comprising:

a cabinet having top, bottom, end and side walls and having aperture means in at least one wall thereof for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting access to said display space;

covering means for said aperture means including a barrier door for substantially covering said access opening, said door being movable for enabling access to products within said display space;

at least one air conduit extending along side top, bottom, rear and side walls about said display space and having an outlet opening and an inlet opening at opposing ends thereof, said outlet opening and said inlet opening being arranged in aerodynamic alignment;

an air band contained within said air conduit which upon leaving said outlet opening will be directed toward and received by said inlet opening to form an air curtain across said access opening along a path inside of said barrier door;

said refrigeration means including a low temperature element;

air moving means for circulating said air band within said air conduit and moving said air band into contact with said low temperature element during a refrigeration cycle of operation;

air defrost means for selectively creating a gap between said barrier door and said access opening;

said air defrost means causing said air moving means to pass ambient air through said cabinet and through said aperture means during a defrost cycle of operation to bring said ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet;

control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle, said air moving means comprising a first air circulation means for selectively propelling a primary refrigerated air band, and a secondary air circulation means for selectively propelling a second air guard band in the same direction as said primary air band during a refrigeration cycle; and

said control means terminating operation of said second air circulation means and causing said primary air band to draw ambient air from outside said cabinet and to contact said low temperature element with said primary air band containing the ambient air during a defrost cycle of operation.

41. A display cabinet according to claim 40, wherein during a defrost cycle of operation said first air circulation means is caused to reverse the flow of said primary air band from the direction of flow of said air band during a refrigeration cycle of operation.

42. A display cabinet according to claim 40, wherein lighting means are included in said cabinet for illuminating said display space.

45. A display cabinet having a refrigeration means and a display space therein comprising:

a cabinet having top, bottom, end and side walls and having aperture means in at least one wall thereof for communicating ambient outside air with the air in said cabinet, said aperture means comprising an access opening for permitting access to said display space;

covering means for said aperture means including at least one barrier door for substantially covering said access opening, said door being movable for enabling access to products within said display space;

at least one air conduit extending along said top, bottom, rear and side walls about said display space and having an outlet opening and an inlet opening at opposing ends thereof, said outlet opening and said inlet opening being arranged in aerodynamic alignment;

an air band contained within said air conduit which upon leaving said outlet opening will be directed toward and received by said inlet opening to form an air curtain across said access opening along a path inside of said barrier door;

said refrigeration means including a low temperature element;

air moving means for circulating said air band within said air conduit and moving said air band into contact with said low temperature element during a refrigeration cycle of operation;

air defrost means for selectively creating a gap between said barrier door and said access opening;

said air defrost means causing said air moving means to pass ambient air through said cabinet and through said aperture means during a defrost cycle of operation to bring said ambient air into contact with said low temperature element to remove frost therefrom and to thereafter eject the defrost ambient air from said cabinet;

control means for selectively operating said air defrost means and said refrigeration means to defrost said low temperature element during a defrost cycle and to refrigerate said cabinet during a refrigeration cycle; and

said covering means including a plurality of barrier doors attached to said display cabinet for substantially covering said access opening, and wherein said air defrost means selectively creates a gap between at least alternate doors in the series of said barrier doors and said access opening during a defrost cycle of operation.

46. A display cabinet according to claim 45, wherein said air defrost means creates a gap between substantially all of said barrier doors and said access openings simultaneously.

47. A display cabinet according to claim 45, wherein said air defrost means comprises a series of door operating mechanisms arranged for individually and selectively creating a gap between each of said barrier doors and said access opening during a defrost cycle.

48. A display cabinet according to claim 45, wherein said air defrost means comprises a door operating mechanism for selectively creating a gap between at least alternate doors in the series of said barrier doors and said access opening.

55. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation.

66. The improvement according to claim 55, wherein said barrier door contains therein a transparent material viewing port.

67. The improvement according to claim 55, wherein a plurality of barrier doors are attached to said display cabinet for substantially covering a plurality of access openings and wherein said air defrost means comprises a series of door operating mechanisms arranged for individually and selectively creating a gap between each of said barrier doors and said access openings during a defrost cycle.

92. The improvement according to claim 55, wherein a heater element is positioned adjacent to said refrigeration means to increase the temperature of the ambient air prior to contact with said refrigeration means.

56. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein one of said air bands is a primary refrigerated air band circulated about said display space, and wherein another of said air bands is a secondary air guard band which is circulated about said primary air band within said cabinet, and wherein said primary refrigerated air band is cooled by contact with said refrigeration means;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operations.

58. The improvement according to claim 56, wherein at least one of said air bands is reversed during a defrost cycle of operation to draw ambient air into said display cabinet through a first portion of the gap between said barrier door and said access opening and to expel ambient defrost air from a second portion of the gap.

61. The improvement according to claim 56, wherein said secondary air guard band is circulated within said display cabinet only during portions of the refrigeration cycle in which said barrier door is open.

57. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

a first air band functioning as a primary refrigerated air band circulated about said display space, a secondary air guard band circulated about said primary air band within said said display cabinet, said primary air band and said secondary air guard band circulated within said display cabinet in the same direction during a refrigeration cycle, air defrost means for selectively creating a gap between barrier door and said access opening for enabling passage of ambient air at least into said primary air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, said air defrost means enabling a reversal of the flow direction of said secondary air guard band during a defrost cycle, and including guide means provided for deflecting at least a portion of said secondary air guard band into said primary air band during a defrost cycle, and said air defrost means enabling ambient air to be drawn into the reversed direction secondary air band through a first portion of the gap between said barrier door and said access opening during a defrost cycle and to expel defrost embient air through a second portion of the gap.

59. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

a first air band functioning as a primary refrigerated air band circulated about said display space, a secondary air guard band circulated about said primary air band within said display cabinet, air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said primary air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, said air defrost means enabling the reversal of the flow direction of said primary refrigerated air band during a defrost cycle of operation to draw ambient air into said display cabinet through a first portion of the gap between said barrier door and said access opening and to expel ambient defrost air from a second portion of the gap, and said air defrost means enabling termination of the flow of said secondary air guard band during a defrost cycle.

60. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to mantain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

a first air band functioning as a primary refrigerated air band circulated about said display space, a secondary air guard band circulated about said primary air band within said display cabinet, air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said primary air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, at least one of said air bands being reversed during a defrost cycle of operation to draw ambient air into said display cabinet through a first portion of the gap between said barrier door and said access opening and to expel ambient defrost air from a second portion of the gap, and including air moving means for said primary and said secondary air guard bands for circulating said air bands in a first direction during a refrigeration cycle and in the opposite direction during a defrost cycle.

62. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at last one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration;

the improvement comprising;

a first air band functioning as a primary refrigerated air band circulated about said display space, a secondary air guard band circulated about said primary air band within said display cabinet, air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said primary air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, and control means for detecting the opening of said barrier door and for operating an air moving means for propelling said secondary air guard band in the same direction as said primary refrigerated air band selectively in response to a predetermined number of openings of said barrier door in the refrigeration cycle.

63. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, at least one barrier door for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet during a refrigeration cycle of operation to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration;

the improvement comprising;

a first air band functioning as a primary refrigerated air band circulated about said display space, a secondary air guard band circulated about said primary air band within said display cabinet, air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said primary air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, control means for sensing the refrigeration condition within said display space, air moving means for propelling said secondary air guard band in the same direction as said primary refrigerated air band depending upon the refrigeration condition sensed, and said control means including means for selectively operating said air moving means.

64. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, a plurality of barrier doors attached to said cabinet for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air at least into said air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, said air defrost means enabling the selective creation of a gap between at least alternate doors in the plurality of doors and said access opening during a defrost cycle of operation.

65. The improvement according to claim 64, wherein said air defrost means creates a gap between substantially all of said barrier doors and said access opening.

68. In a display cabinet having refrigeration means and a display space therein accessible through at least one access opening, a plurality of barrier doors attached to said display cabinet for substantially covering said access opening, and means for providing a plurality of air bands for selective circulation within said cabinet to maintain a flow pattern inside of said cabinet adjacent to said barrier door, wherein at least one of said air bands is cooled by contact with said refrigeration means;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier doors and said access opening for enabling passage of ambient air at least into said air band in contact with said refrigeration means to remove frost therefrom during a defrost cycle of operation, said air defrost means comprising a door operating mechanism for selectively creating a gap between at least alternate doors of said plurality of doors and said access opening.

69. In a display cabinet having refrigeration means and a display space therein accessible for product storage and selection through an access opening, at least one barrier door for substantially covering said access opening, a first air circulation means for propelling a primary refrigerated air band within said display cabinet, a second air circulation means for selectively propelling a secondary air guard band in the same direction as said primary air band during a refrigeration cycle, a primary air conduit arranged inside said cabinet about said display space for containing said primary refrigerated air band, and a secondary air conduit arranged within said cabinet adjacent to said primary air conduit to the exterior side thereof for containing said secondary air guard band, said primary air band cooled by contact with said refrigeration means;

the improvement comprising;

an air defrost means for selectively creating a gap between said barrier door and said access opening for enabling passage of ambient air into said primary air conduit during a defrost cycle to propel the ambient air into contact with said refrigeration means to remove frost therefrom.

70. The improvement according to claim 69, wherein said first air circulation means reverses the direction of flow of said primary air band during a defrost cycle, and wherein said second air circulation means prevents circulation of said secondary air band during the defrost cycle of operation.

71. In a display cabinet having refrigeration means and a display space therein accessible for product storage and selection through an access opening, at least one barrier door for substantially covering said access opening, and an air moving means for circulating a primary air band and a secondary air guard band within said cabinet, said primary air band circulated in contact with said refrigeration means, said air movement means propelling said primary and said secondary air bands in a first direction during a refrigeration cycle and in the opposite direction in a defrost cycle, a primary air conduit arranged inside said cabinet about said display space for containing said primary air band, and a secondary air conduit arranged within said cabinet adjacent to a substantial portion of said primary air conduit, said secondary air conduit connected at an inlet end thereof to said primary air conduit, said primary and said secondary conduits being separated along the lengths thereof from said secondary conduit inlet to the outlet end thereof, and said cabinet including a common conduit inlet chamber for said primary air band and said secondary air band;

the improvement comprising;

air defrost means for selectively creating a gap between said barrier door and said access opening for enabling the passage of ambient air into at least said primary air band during a defrost cycle to bring the ambient air into contact with said refrigeration means to remove frost therefrom.

72. The improvement according to claim 71, wherein both of said primary air band and said secondary air band are propelled by said air moving means in the same direction during a refrigeration cycle and in the opposite direction during a defrost cycle of operation.

73. A method of operating a refrigerated display cabinet comprising a cabinet having a display space therein, and aperture means in at least one wall thereof for communicating ambient outside air with the air in the cabinet, the aperture means comprising an access opening for permitting products to be moved into and out of the display case, covering means for the aperture means including a barrier door for substantially covering the access opening, the barrier door being movable for enabling access to the cabinet, at least one air conduit extending about the display space and having an outlet opening and an inlet opening at opposite ends thereof, with the outlet opening and inlet opening being arranged in aerodynamic alignment so that air leaving the air conduit outlet opening will be directed toward the received by the inlet opening, and an air moving means for propelling a refrigerated air band through the air conduit during a refrigeration cycle and for propelling ambient air through the cabinet during a defrost cycle, and a refrigeration means arranged within the air conduit;

the method comprising the steps of;

selectively operating the display cabinet in a refrigeration cycle of operation and in a defrost cycle of operation;

during a refrigeration cycle, circulating the air band through the air conduit so that air is expelled from the outlet opening and received by the inlet opening so as to form an air curtain across the access opening in the cabinet along a path inside of the barrier door, and propelling the air band through the refrigeration means;

during a defrost cycle operation, terminating operation of the refrigeration means, causing ambient air to be drawn into the cabinet, pass through a substantial portion of the air conduit, and across the refrigeration means, causing the defrost ambient air to be ejected from the cabinet, and creating a gap between the barrier door and the access opening to enable ambient air through-flow;

whereby ambient air is drawn into the air band and across the refrigeration means to defrost the same by communicating ambient air with the air band in the display cabinet.

74. A method according to claim 73, wherein the aperture means includes an air passage port in a wall of the cabinet including the additional step of causing ambient air to move through the cabinet by propelling ambient air through the air passage port and through the gap between the barrier door and the access opening during a defrost cycle.

75. A method according to claim 73, wherein the aperture means includes an air passage port in a wall of the cabinet, and including the additional steps of causing ambient air to be drawn into the air conduit through the air passage port and to thereafter pass through the refrigeration means and to be ejected from the display cabinet through the gap between the barrier door and the access opening during a defrost cycle.

76. A method according to claim 73, wherein the aperture means includes an air passage port in a wall of the cabinet, and including the additional steps of causing ambient air to be drawn into the air conduit through the gap between the barrier door and the access opening during a defrost cycle and to thereafter pass through the refrigeration means and to be ejected from the display cabinet through the air passage port.

77. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional step of terminating movement of the secondary air band during the defrost cycle.

78. A method according to claim 73, wherein the air conduit is a primary air conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional steps of;

during a defrost cycle of operation reversing the flow direction of the primary and secondary air bands, causing ambient air to be preferentially drawn into the primary air band and passed through the refrigeration means, and thereafter ejecting the defrost ambient air from the cabinet through the gap between the barrier door and the access door.

79. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and including a secondary air conduit containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle, the secondary air conduit having an air guidance means arranged therein for deflecting at least a portion of the flow of the secondary air band into the primary air conduit during a defrost cycle of operation;

including the additional steps of;

reversing the flow direction of the secondary air band, causing ambient air to be preferentially drawn into the secondary air band through the gap between the barrier door and the access opening during a defrost cycle, passing the secondary air band containing the ambient air through the refrigeration means to defrost the same, and to thereafter eject the defrost ambient air from the cabinet through the gap between the barrier door and the access door.

80. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band propelled by a first air circulation means during a refrigeration cycle, and including a secondary air conduit containing a secondary air guard band propelled by a secondary air circulation means in the same direction as the primary air band during the refrigeration cycle, including the additional steps of:

terminating operation of said second air circulation means during the defrost cycle, and reversing the flow direction of the first air circulation means to draw ambient air into the cabinet through a top portion between the gap between the barrier door and the access opening and to eject the defrost ambient air from a lower portion of the gap during the defrost cycle of operation.

81. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by th air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional step of preventing movement of the secondary air band during portions of the refrigeration cycle in which the barrier door is not opened.

82. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional steps of detecting the opening of the barrier door, and controlling the propulsion of the secondary air band selectively in response to the opening of the barrier door during a refrigeration cycle.

83. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional steps of sensing the refrigeration condition within the display space in the cabinet, and selectively propelling the secondary air band in the same direction as the primary refrigerated air band in response to the refrigeration condition.

84. A method according to claim 73, wherein the air conduit is a primary conduit containing a primary refrigerated air band during a refrigeration cycle and wherein a secondary air conduit is provided for containing a secondary air guard band propelled by the air moving means in the same direction as the primary air band during the refrigeration cycle;

including the additional steps of detecting openings of the barrier door, and controlling propulsion of the secondary air band in the same direction as the primary refrigerated air band selectively in response to a predetermined number of the openings of the barrier door during a refrigeration cycle.

85. A method of operating a refrigerated display cabinet having a cabinet containing a display space therein, and aperture means comprising an access opening in at least one wall thereof for communicating ambient outside air with the air in the cabinet and for permitting access to the display space, covering means for the aperture means including a barrier door for substantially covering the access opening, the barrier door being movable for enabling access to the cabinet, a primary air conduit extending about the display space and having an outlet opening and an inlet opening at opposite ends thereof, with the outlet opening and the inlet opening being arranged in aerodynamic alignment so that air leaving the primary air conduit outlet opening will be directed toward and received by the inlet opening;

a refrigeration means arranged within the primary air conduit; and

a secondary air conduit extending about a substantial portion of said primary conduit and having a secondary outlet opening and a secondary inlet opening at opposite ends thereof;

the method comprising the steps of;

selectively operating the display cabinet in a refrigeration cycle of operation and a defrost cycle of operation;

during a refrigeration cycle of operation, circulating a primary air band through the primary air conduit so that air is propelled through the primary outlet opening and received by the primary inlet opening so as to form an air curtain across the access opening in the cabinet along a path inside of the barrier door;

propelling the primary air band through the refrigeration means;

during the refrigeration cycle of operation, circulating a secondary air band through the secondary air conduit in the same direction as the primary air band so that air is propelled through the secondary outlet opening and received by the secondary inlet opening so as to form a secondary air guard curtain across the access opening in the display cabinet along a path inside of the barrier door;

during a defrost cycle of operation, causing ambient air to be drawn into the cabinet and to pass across the refrigeration means and through the primary air conduit and be expelled from the display cabinet, creating a gap between the barrier door and the access opening, to enable ambient air through-flow;

whereby ambient air is thereby drawn into the cabinet and across the refrigeration means to defrost the same by communicating ambient air with the cabinet.

86. A method according to claim 85, wherein the aperture means includes an air passage port in a wall of the cabinet for communicating with the primary air conduit and including the additional step of:

causing ambient air to be moved through the cabinet by moving ambient air through the air passage port and through the gap between the barrier door and the access opening during a defrost cycle.

87. A method according to claim 86, including the additional step of:

terminating circulation of the secondary air band during a defrost cycle of operation.

88. A method according to claim 85, including the additional step of:

causing ambient air to be drawn into the primary air conduit through a first portion of the gap between the barrier door and the access opening, and to thereafter pass across the refrigeration means and to thereafter be ejected through a second portion of the gap during a defrost cycle.

89. A method according to claim 85, wherein the curtain of refrigerated air extends in a substantially vertical direction across the access opening in the cabinet.

90. A method according to claim 85, wherein the air flow through the secondary air conduit during the defrost cycle of operation is in a direction opposite the direction of air flow in the secondary air conduit during a refrigeration cycle of operation.

91. A method according to claim 90, wherein the quantity of air flowing through the secondary air conduit during a defrost cycle of operation is 25-50% greater than the air flow in the secondary air conduit during the refrigeration cycle of operation.