Abstract:
A flexible door panel cold storage door system incorporates a flexible movable door panel having an internal support frame assembly and the door panel has a plurality of gasket sections removably attached to a cold space surface of a door panel jacket with each gasket section having at least one ferrous gasket target and the gasket sections are aligned and cooperate with a plurality of electromagnets that are mounted in a doorframe assembly when the door panel is in a closed position. The electromagnets are mounted in wells in the doorframe assembly and are powered on when the door panel is in the closed position and the wells are interconnected by a ventilation channel that conducts air heated by operation of the electromagnets through the ventilation channel and into and through a bottom sweep assembly of the door panel in a closed loop. The heated air reduces or eliminates problems of icing in the immediate vicinity of the periphery of the door panel and reduces or eliminates problems of freezing of the door panel in a closed position. The gasket sections are easily replaced if worn or damaged during use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     In modern society, cold storage facilities often have forklift accessible door openings into a cold space from a warm space. Various barrier devices including overhead suspended sliding insulated doors have been used in the past to provide some measure of thermal control and to secure the door openings from unwanted intrusions. 
     With many prior art doors, there have been problems of unwanted heat exchange between the cold and warm spaces, ice buildups in and around the door opening, and unwanted freezing of the closed door in the door opening. Additionally, many prior art doors are more susceptible to unwanted impact damage from forklifts, forklift loads, or other moving objects that may impact the door during operations in or about the door opening by such equipment and objects. 
     Forklift operations through and near door openings and associated sliding doors in cold storage facilities often result in impact incidents between the forklift or forklift loads and the doors that selectively close the door opening resulting in unwanted damage to the door that often necessitates expensive repair or replacement of the door or associated structures. 
     The present invention relates to a novel flexible door panel cold storage door system having at least one overhead track-mounted horizontally sliding flexible door panel useful for the convenient closing and opening of a door opening into a cold storage area that incorporates features that reduce or eliminate the above mentioned problems. 
     The instant invention incorporates a novel movable door panel that reduces or eliminates damage to the door panel that might result from impact incidents and reduces maintenance and downtime as compared with many other prior art cold storage sliding doors that would suffer significant damage and require significant maintenance and undesirable downtime from comparable impact incidents. The instant invention is designed for easy and convenient repair in the event of any damage from impact incidents involving the door panel. 
     The instant invention incorporates a movable flexible door panel having spaced vertical suspension cables, at least two vertical stiffeners, and at least one horizontal stiffener closely and elastically attached between and to the vertical stiffeners and provides a durable panel that has improved resistance to undesired breaching or damage of the panel by accident or by malicious intent by unauthorized entities or forces. 
     The door hanger assemblies of the instant invention allow the door panel to swing outward away or inward toward the wall during an impact incident and lessen the likelihood of damage to the hanger assemblies and to the overhead horizontal track and carriage system to which the hanger assemblies are attached 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a novel flexible door panel cold storage door system  10  for selectively blocking and unblocking a door opening  8 , having a surrounding doorframe assembly  12 , in a boundary wall  6  between a cold space  2  and a warm space  4  in a cold storage facility with a movable flexible door panel  66 . 
     The novel flexible door panel cold storage door system uses heat generated by the operation of a plurality of electromagnets  36  to reduce or eliminate frost and ice in and around the door opening  8 , the doorframe assembly  12 , and the door panel  66 . 
     In the best embodiment, the electromagnets  36  promote an improved sealing between the door panel  66  and a doorframe assembly  12 ; the electromagnets generate heat that is dispersed into a heat dispersion layer  34 , a nonferrous doorframe outer jacket  46 , and a plurality of gasket sections  148  and  164  attached to a door panel jacket  104  to preclude icing and freezing of a sealing zone between the door panel and the doorframe assembly. The electromagnets preferably are powered when the door panel is in a selected stationary closed position and generate heat that warms air that is circulated through a frame core ventilation channel  32  in the doorframe assembly in close proximity to an interface between the doorframe assembly and the movable door panel. 
     In the best embodiment, the electromagnets are powered to attract ferrous gasket targets  154  when the door panel is in a closed position and air warmed by the operation of the electromagnets is circulated by at least one inline ventilation fan  40  in a substantially closed loop through the ventilation channel  32  that interconnects a plurality of electromagnet wells  26 ,  28 ,  30  in which the electromagnets are mounted and through at least one interconnected bottom sweep assembly air channel  144  when the door panel is in a closed position. Additionally, in the best embodiment a heat dispersion layer  34  that is in close contact with portions of the electromagnets disperses heat from the operating electromagnets to help warm the overlaying doorframe outer jacket  46 . 
     The best embodiment of the instant invention provides a seal between the door panel  66  and the doorframe assembly  12  and a close contact sliding seal between a bottom sweep assembly  124 ,  324 ,  424  of the door panel and a floor surface within the door opening  8 . 
     In the best embodiment of the invention, the bottom sweep assembly air channel  144 ,  344 ,  444  circulates warmed air that reduces or eliminates ice build-up beneath the door panel and lessens or eliminates the likelihood that the door panel in the closed position will freeze to the floor surface beneath the door panel structure. 
     Additional and various other objects and advantages attained by the invention will become more apparent as the specification is read and the accompanying figures are reviewed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a front-side view of a flexible door panel cold storage door system  10  of the preferred embodiment showing a flexible door panel  66  in an open position with stay roller assemblies not shown; 
         FIG. 2A  is a front-side plan view of a vertical left frame core  16  showing a plurality of electromagnet wells  26  and a half-length electromagnetic well  28 , and a frame core ventilation channel  32  communicating into, through, and between each well and communicating to, through, and extending beyond an inline ventilation fan  40  (shown schematically); 
         FIG. 2B  is a front-side plan view of a horizontal top frame core  20  showing a plurality of electromagnet wells  26  between two half-length electromagnet wells  30  and a frame core ventilation channel  32  communicating into, through, and between each well; 
         FIG. 2C  is a front-side plan view of a vertical right frame core  24  showing a plurality of electromagnet wells  26  and a half-length electromagnetic well  28 , and a frame core ventilation channel  32  communicating into, through, and between each well and communicating to, through, and extending beyond an inline ventilation fan  40  (shown schematically); 
         FIG. 3A  is a partial front-side plan view of the vertical left frame core  16  shown in  FIG. 2A  mounted adjacent and perpendicularly to a left end of the top horizontal frame core  20  shown in  FIG. 2B  with cooperating and adjacent half-length electromagnet wells  28  and  30  aligned to receive and hold an electromagnet  36  and showing a plurality of electromagnets mounted with one in each of the plurality of electromagnet wells, unlabeled arrows and arrow A depict air flow leftward and downward through the frame core ventilation channel  32  and out of the ventilation channel downstream of the inline ventilation fan  40 ; 
         FIG. 3B  is a partial front-side plan view of the vertical right frame core  24  shown in  FIG. 2C  mounted adjacent and perpendicularly to a right end of the top horizontal frame core  20  shown in  FIG. 2B  with cooperating and adjacent half-length electromagnet wells  28  and  30  aligned to receive and hold an electromagnet  36  and showing a plurality of electromagnets mounted with one in each of the plurality of electromagnet wells, unlabeled arrows depict airflow upward and leftward through the frame core ventilation channel  32 ; 
         FIG. 4A  is an exploded perspective view of an intermediate gasket section  148 ; 
         FIG. 4B  is a perspective view of the intermediate gasket section  148  shown in  FIG. 4A ; 
         FIG. 5A  is an exploded perspective view of a bottom sweep gasket section  164 ; 
         FIG. 5B  is a perspective view of the bottom sweep gasket section  164  shown in  FIG. 5A ; 
         FIG. 6  is a front-side view of the flexible door panel cold storage door system  10  of the preferred embodiment showing the flexible door panel  66  in a closed position and showing two stay roller assemblies  184 ; 
         FIG. 7  is a partial cross-sectional view along the line of  7 - 7  in  FIG. 6  of an upper portion of the flexible door panel cold storage door system  10 ; 
         FIG. 8  is an enlarged view of an indicated portion of  FIG. 7 ; 
         FIG. 9  is a partial cutaway cross-sectional view along the line of  9 - 9  in  FIG. 6  of a lower portion of the flexible door panel cold storage door system  10  showing a partially cutaway stay roller assembly  184  and showing a portion of a sealing zone that lies between a plurality of gasket sections and a nonferrous doorframe outer jacket  46  (bottom sweep assembly not shown); 
         FIG. 10  is an enlarged view of an indicated portion of  FIG. 9 ; 
         FIG. 11  is a partial cross-sectional view along the line of  11 - 11  in  FIG. 6  of a lower portion of the flexible door panel cold storage door system  10  unlabeled arrows depict airflow through the frame core ventilation channel  32 ; stay roller assembly not shown; a bottom sweep assembly  124  is shown compressed against the floor surface; 
         FIG. 12  is an enlarged view of an indicated portion of  FIG. 11  unlabeled arrow depicts airflow; 
         FIG. 13  is an enlarged view of an indicated portion of  FIG. 11 ; 
         FIG. 14  is an enlarged view of an indicated portion of  FIG. 11 ; 
         FIG. 15  is an enlarged view of an indicated portion of  FIG. 11  unlabeled arrow depicts airflow from the ventilation channel  32  through a bottom sweep gasket transverse bore  174  and into a bottom sweep assembly air channel  144 ; 
         FIG. 16  is an enlarged view of an indicated portion of  FIG. 11 ; 
         FIG. 17  is a partially exploded perspective view of a support frame assembly  74 ; 
         FIG. 18  is a partial exploded perspective view of the support frame assembly  74  shown in  FIG. 17  (not to the same scale); 
         FIG. 19  is a partial perspective view of the support frame assembly  74  shown in  FIG. 17  (not to the same scale); 
         FIG. 20  is a partially exploded perspective view of a flexible door panel with a door panel jacket removed showing a plurality of flexible insulation sheets  72  that encapsulate and sandwich the support frame assembly  74 ; 
         FIG. 21  is a partially exploded perspective view of a door panel showing the encapsulated support frame assembly  73  shown in  FIG. 20  along side a door panel jacket  104  that will receive and retain the encapsulated support frame assembly within said jacket; 
         FIG. 22A  is a partially exploded perspective view of a jacketed encapsulated support frame assembly  75  shown in  FIG. 21  showing a plurality of hook pads  110 ,  112 ,  114 ,  130 ,  146  to be attached to the jacketed encapsulated support frame assembly; 
         FIG. 22B  is a perspective view of the jacketed encapsulated support frame assembly  75  shown in  FIG. 21  showing the plurality of hook pads  110 ,  112 ,  114 ,  130 ,  146  attached to said jacketed encapsulated support frame assembly; 
         FIG. 23A  is an exploded perspective view of a bottom sweep assembly  124 ; 
         FIG. 23B  is an enlarged view of an indicated portion of  FIG. 23A ; 
         FIG. 23C  is an enlarged view of an indicated portion of  FIG. 23A ; 
         FIG. 23D  is a plan view of the bottom sweep assembly  124  shown in  FIG. 23A ; 
         FIG. 24  is a partially exploded rear-side plan view of a flexible door panel  66 ; 
         FIG. 25  is a rear-side plan view of the flexible door panel  66  shown in  FIG. 24  showing two side skirt assemblies  116 , a top skirt assembly  120 , a bottom sweep assembly  124 , seven intermediate gasket sections  148 , and two bottom sweep gasket sections  164 , each removably attached by attachment means to the jacketed encapsulated support frame assembly  75  shown in  FIG. 22B  (preferably attachment means are cooperating hook pads and loop pads of well understood hook and loop attachment pad systems with a hook pad attached to one surface to be joined and a loop pad attached to the other surface to be joined; attachment means could also include cooperating pairs of permanent magnetic strips with a first magnetic strip attached to one surface to be joined and a second magnetic strip attached to the other surface to be joined; attachment means could also include use of a suitable adhesive to join surfaces together); 
         FIG. 26  a partially exploded perspective view of a stay roller assembly  184 ; 
         FIG. 27  a perspective view of the stay roller assembly  184  shown in  FIG. 26 ; 
         FIG. 28  is partial perspective view of a portion of the stay roller assembly  184  shown in  FIG. 27 ; 
         FIG. 29  is a perspective view of a door hanger assembly  56 ; 
         FIG. 30  is a front-side view of an alternative flexible door panel cold storage door system  310  having a flexible door panel having a left flexible door leaf  220  and a right flexible door leaf  224  shown in an open position with stay roller assembly  184  and cooperating stay roller assembly  384  shown; 
         FIG. 31A  is a partial cross-sectional view along the line of  31 A- 31 A in  FIG. 30  of a lower portion of the alternative flexible door panel cold storage door system showing the left flexible door leaf  220  in an open position alongside a boundary wall  6  between a cold space  2  and a warm space  4 ; 
         FIG. 31B  is a partial cross-sectional view along the line of  31 B- 31 B in  FIG. 30  of a lower portion of the alternative flexible door panel cold storage door system showing the right flexible door leaf  224  in an open position alongside a boundary wall  6  between a cold space  2  and a warm space  4 ; 
         FIG. 32  is a front-side view of the alternative flexible door panel cold storage door system, shown in  FIG. 30 , having a flexible door panel having a left flexible door leaf  220  and a right flexible door leaf  224  shown in a closed position; 
         FIG. 33  is a partial cross-sectional view along the line of  33 - 33  in  FIG. 32  of a lower portion of the alternative flexible door panel cold storage door system shown in a closed position and showing a left leaf sealing flap  222  overlapping a portion of the right flexible door leaf  224 , a right leaf sealing flap  226  overlapping a portion of the left flexible door leaf  220 , and showing a left leaf cooperating sealing and closing magnet strip  232  in facing proximity to a right leaf cooperating sealing and closing magnet strip  234 ; 
         FIG. 34  is a partial perspective view of a left flexible door leaf  220  showing a communicating interface air port  242  in a left leaf bottom sweep assembly  324  that communicates with a left leaf bottom sweep assembly air channel  344  and that in the closed position cooperates and communicates with a corresponding abutting interface air port  442  in a right leaf bottom sweep assembly  424  to allow airflow between the two leaf bottom sweep assembly air channels; and 
         FIG. 35  is a front-side plan view of an alternative nonferrous doorframe outer jacket  346  having a plurality of window openings  348  with each window opening overlaying a respective electromagnet  36 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 through 35 , a flexible door panel cold storage door system  10  for selectively blocking and unblocking a door opening  8  in a boundary wall  6  between a cold space  2  and a warm space  4  includes a doorframe assembly  12 , having a vertical left frame  14 , a horizontal top frame  18 , and a vertical right frame  22  mounted to or in said wall to contiguously define together with a floor surface between the left frame and the right frame the door opening. 
     The left frame  14  has a left frame core  16 ; the top frame  18  has a top frame core  20 ; and the right frame  22  has a right frame core  24 ; each frame core has a frame core top surface and a longitudinal top surface centerline; the frame cores are preferably made of wood or a suitable composite material. 
     A plurality of open electromagnet wells  26  are formed in the frame cores and distributed along and proximate to the centerlines; a frame core ventilation channel  32  is formed or routed in the frame core top surfaces. 
     The ventilation channel  32  has a first end near said left frame core&#39;s bottom end and the ventilation channel contiguously and serially communicating to and through each well in each frame core and the ventilation channel having a second end near the right frame core&#39;s bottom end. 
     A plurality of electromagnets  36  are operably mounted one electromagnet in each well and mounted substantially flush to the adjacent frame core top surface that surrounds that respective well. The electromagnets  36  are selectively energized by a D/C power supply  38  that is electrically connected to said electromagnets; the power supply is selectively controlled by an electric door operator control box  50 . 
     When the door is in the closed position, the electromagnets  36  are powered on to generate a plurality of magnetic fields to attract a plurality of ferrous gasket targets  154  toward respective electromagnets and to generate heat to warm air circulating in close proximity to the electromagnets. 
     A signal to open and a signal to close the door can be initiated by a manually operated switch connected to the control box or by a radar system, an induction loop system, a radio transmitters/receiver system, a photocell system, a pull-cord switch system, or some other suitable signaling device known in the art that can communicate with the control box. 
     Preferably, each installation of the instant invention includes a D/C power supply  38  that is a 12 volt system that is custom fabricated to supply the required wattage needed to power the number of electromagnets used in the specific door system being installed; the power will vary depending upon the door size and the number and size of the electromagnets used. 
     Preferably, the D/C power supply  38  is controlled via a 120 volt power switch located inside of the door operator control box  50 . The power switch is selectively activated in response to a door operator control switch that is selectively activated via a manufacturer&#39;s supplied pull cord, a push button, a magnetic floor loop/forklift detection, a radio remote, or another suitable activation system. The power switch is configured to switch the power of the 12 volt power supply to the electromagnets ON when the door panel is in a closed position and OFF when the door is signaled to be opened, while the door panel is in motion, and while the door panel is in an open position. 
     Preferably, the power supply  38  sends a brief (fraction of a second) reverse current to the pole plates of the electromagnets when the electromagnets are powered off to scramble the magnetic fields and help ensure that the ferrous gasket targets  154  release from the electromagnets during opening of the door opening by the moving door panel. 
     Preferably, after a signal to close the door panel from an open position to a closed position, the power switch is configured with about a 5 second delay regarding the powering of the electromagnets to ON to allow the door panel to fully close before powering on the electromagnets. 
     In a fully-assembled preferred embodiment of the invention, a nonferrous doorframe outer jacket  46  is attached, preferably with removable fasteners, to the frame cores  16 ,  20 , and  24  to substantially cover the frame cores, the ventilation channel  32 , and the electromagnets  36 . 
       FIG. 35  shows an alternative nonferrous doorframe outer jacket  346  having a plurality of window openings with each window opening overlaying a respective electromagnet  36 . 
     Preferably, there are two air ventilation ports  42  and  44  through the outer jacket  46  and the ventilation ports communicate with the ventilation channel  32  with one ventilation port located proximate the first end of the ventilation channel and the other ventilation port located proximate the second end of the ventilation channel. 
     A movable flexible door panel  66  has a door panel jacket  104  and has a door panel periphery and the door panel is selectively disposable against the doorframe outer jacket  46  to at least partially block the door opening  8  when in a closed position, and the door panel substantially unblocking the door opening when in an open position. The door panel jacket  104  has an upper end and a lower end. 
     Two bottom sweep gasket sections  164  are removably attached by attachment means to the door panel jacket proximate the lower end along the door panel periphery that overlaps two portions of the doorframe outer jacket when the door panel is in the closed position with one bottom sweep gasket section located proximate the first end and the other bottom sweep gasket section located proximate the second end. The attachment means preferably comprises cooperating hook pads and loop pads selectively fixed to the panel jacket and to each gasket section. The hook pads and loop pads could be replaced by cooperating permanent magnet strips fixed one to the panel jacket and one to each gasket section or replaced by use of a suitable adhesive or by stitching with needle and thread. 
     A plurality of intermediate gasket sections  148  are removably and contiguously attached by attachment means to the door panel jacket between and proximate to two bottom sweep gasket sections  164  and along a contiguous portion of the door panel periphery that overlaps a contiguous portion of the doorframe outer jacket when the door panel is in the closed position and the gasket sections are operably configured to form an air seal with the doorframe outer jacket when the door panel is in the closed position. 
     Preferably, in each embodiment of the invention, each gasket section has at least one ferrous gasket target  154  located proximate the gasket section&#39;s top surface spaced away from the door panel jacket  104  and towards the doorframe outer jacket  46  and each ferrous gasket target is aligned to cooperate and be magnetically attracted by and towards one of the electromagnets when the door panel is in the closed position and the electromagnets are powered on (energized). 
     In all embodiments of the flexible panel cold storage door system  10  invention, a doorframe assembly  12  has a vertical left frame  14  having a left frame core  16  and a bottom end, a horizontal top frame  18  having a top frame core  20 , and a vertical right frame  22  having a right frame core  24  and a bottom end; the frame cores have a plurality of electromagnet wells  26  formed in them to receive and mount a plurality of electromagnets  36 , the wells may include cooperating half-length electromagnet wells  28  and  30  that together in respective abutting pairs form a well that may receive and mount an electromagnet; a frame core ventilation channel  32  is formed in the frame core top surfaces and the ventilation channel has a first end near the left frame core&#39;s bottom end and the ventilation channel contiguously and serially communicates to and through each well in each frame core and the ventilation channel has a second end near the right frame core&#39;s bottom end. 
     Preferably, a heat dispersion layer  34  preferably made of aluminum foil is interposed between the frame cores and the plurality of electromagnets  36  that are mounted in the wells  26  and cooperating half-length wells  28  and  30  and the dispersion layer proximately lines the wells and the core frame ventilation channel  32  and substantially covers the frame core top surfaces. 
     A D/C power supply for electromagnets  38 , preferably a 12 volt system, selectively powers the electromagnets  36  and one or more inline ventilation fans  40  that are emplaced in the core frame ventilation channel  32  to move air through the ventilation channel. 
     Preferably, there are two air ventilation ports  42  and  44  in the nonferrous doorframe outer jacket  46  and each ventilation port communicates with the core frame ventilation channel  32  with one port located proximate the first end of the ventilation channel and the other port located proximate the second end of the ventilation channel. 
     The invention preferably is operatively suspended from a conventional overhead horizontal track and carriage system  48  that is controlled by an electric door operator control box  50 . The carriage system  48  includes at least one carriage assembly  52  or  352  and  452  that is or are movably mounted on an overhead horizontal track  54 ,  254  that is mounted above and across the horizontal top frame  18  and at least two door hanger assemblies  56  attach a flexible door panel  66  to the carriage assembly or attach two leaves  220  and  224  to respective carriage assemblies  352  and  452 . 
     Preferably, each door hanger assembly  56  has a hanger bracket  58  that is attached to a header  68  of the door panel  66  and the bracket rotatably mounts a horizontal hanger member  60  that is preferably secured in the bracket by a retainer  62  such as a C-clip or comparable securing device, the horizontal hanger member has a midpoint transverse bore to receive and retain a transverse vertical hanger member  64  that is preferably a threaded bolt and the vertical hanger member attaches the hanger assembly to a carriage assembly  52  or to one of two alternate carriage assemblies  352  and  452 . 
     In the best embodiment, a flexible door panel  66  has an internal support frame assembly  74  that supports the door panel and suspends the door panel from a carriage assembly  52  or  352  and  452 ; each support frame assembly  74  has a header  68  spaced from and connected to at least one door panel base plate segment  80  by at least two spaced vertical suspension cables  78 , each of the two suspension cables is threaded lengthwise through and retained respectively in one of at least two vertical tube stiffeners  86 ; at least one horizontal tube stiffener  94  is attached proximately and elastically to and perpendicularly between the two vertical tube stiffeners; a plurality of flexible insulation sheets  72  facing and proximate to one another with at least one insulation sheet on each side of the frame assembly and the insulation sheets supported by the frame assembly; a door panel jacket  104  having an upper end and a lower end encapsulates the support frame assembly and the insulation sheets; and at least two door hanger assemblies  56  are spaced and aligned coaxially and attached proximate the upper end to the header. 
     Preferably, as shown in  FIG. 20 , a header relief  70  to receive the header  68  is formed in upper portions of the outermost insulation sheets  72  and a base plate segment relief  82  is formed in lower portions of the outermost insulation sheets to receive base plate segments  80  to provide smoother outside faces to the plurality of flexible insulation sheets; and a support frame assembly relief  76  is provided in a facing surface of at least one of the insulation sheets immediately adjacent the support frame assembly  74  to closely receive the support frame assembly. 
     Preferably, each vertical suspension cable  78  at each end has a threaded cable end coupler  84  to interact at the top of the support frame assembly  74  with a respective wing nut  90  to attach the cable to the header  68  and at the bottom of the support frame assembly with a respective nut  92  to attach the cable to a bottom plate segment  80  and to allow vertical adjustment of the length of each cable and thereby allowing adjustment of the amount of separation between the header and the bottom plate segments after the door panel is assembled. 
     Preferably, each vertical tube stiffener  86  has at least one vertical tube stiffener transverse bore  88  aligned with a corresponding bore in at least one other vertical tube stiffener; at least one horizontal tube stiffener  94  is attached proximately and elastically to and perpendicularly between the two vertical tube stiffeners by an elastic cord  100  or a spiral spring threaded through the horizontal tube stiffener and through and anchored beyond each vertical tube stiffener transverse bore by an anchor clip  102  or other suitable retaining device. 
     Preferably, each horizontal tube stiffener  94  has a horizontal tube stiffener transverse bore  96  associated with each vertical suspension cable  78  that intersects the horizontal tube stiffener for receiving there through the respective cable. 
     Preferably, each stiffener transverse bore  88  and  96  has a tube grommet  98  preferably made of resilient rubber or other suitable material inserted in each transverse bore to encircle a respective cable, cord, or spiral spring threaded there through. 
     As shown in  FIGS. 7 ,  11 ,  14 ,  22 A, and  22 B, in the best embodiment of the invention, the door panel jacket  104  has at least one hook pad  110 ,  112 ,  114 ,  130 , or  146  attached to each of five of six outer surfaces of the door panel jacket: a panel jacket warm space surface  106  and a panel jacket cold space surface  108  spaced parallel from each other together have a lower end attachment hook strip  130  attached to, about, and encircling the lower end of the door panel; the cold space surface has at least one perimeter hook pad  146  attached along left, top, and right portions of the cold space surface&#39;s perimeter; two panel jacket side surfaces each having at least one panel jacket side surface hook pad  110  attached; and a panel jacket top surface has at least one panel jacket top surface hook pad  112  attached. Preferably, two panel jacket top surface end hook pads  114  are attached to the panel jacket top surface at opposite ends of the panel jacket top surface and bracket the panel jacket top surface hook pad  112 . 
       FIG. 23A to 25  show the best embodiment of a bottom sweep assembly  124  having a flexible two-layer bottom sweep base strip  126  having two base strip apertures  127 ; a bottom sweep attachment loop strip  128  attached along an upper length of an inner side of the base strip, the bottom sweep attachment loop strip removably attaches the bottom sweep assembly to the lower end attachment hook strip  130 ; at least one, but preferably two, bottom sweep gasket section hook pads  132 , each having a bottom sweep gasket section hook pad aperture  134  are spaced and attached on an outer side of the base strip and each hook pad aperture communicates respectively and defines with one of the base strip apertures one of two bottom sweep assembly air ports  142 , and when the sweep assembly is attached to the door jacket, each sweep gasket section hook pad respectively is aligned to engage a bottom sweep gasket section loop pad  176  of a bottom sweep gasket section  164 . 
     Preferably, adjacent each sweep gasket section hook pad  132  is attached a bottom sweep side skirt hook pad  136  that aligns with a respective panel jacket side surface when the bottom sweep assembly  124  is attached around and extended downward beyond the lower end of the panel jacket and the sweep assembly air ports  142  communicate with a bottom sweep assembly air channel  144  preferably defined by a bottom surface of the jacket, an inner surface of the base strip  126  below the bottom sweep attachment loop strip  128 , and the underlying floor surface. 
     Preferably, the base strip  126  is secured as a closed loop strip to, about, and encircling the lower end of the jacket by a bottom sweep closure loop pad  138  attached to one end of the base strip removably engaging a bottom sweep closure hook pad  140  attached to the other end of the base strip. 
     Referring to  FIGS. 24 and 25 , preferably, there are two bottom sweep gasket sections  164  removably attached by attachment means to at least one cold space surface perimeter hook pad  146  respectively along bottom portions of a left periphery and a right periphery of the cold space surface  108 . 
     In the best embodiment, see  FIGS. 5A and 5B , each bottom sweep gasket section  164  is an elongate insulating member having a substantially rectangular cross-section and having a bottom sweep gasket section core  166  made from an extruded insulating foam or some other suitable insulating material; a bottom sweep gasket section air channel  168  having a closed end at the bottom sweep gasket section core&#39;s bottom end is formed substantially along the longitudinal length away from the closed end and along the midline of the bottom sweep gasket section&#39;s top core surface, a bottom sweep gasket section core air port  170  is formed transverse through the sweep gasket section core near the closed end; a bottom sweep gasket section outer jacket  172  substantially covers and overlays the sweep gasket section core, the sweep gasket section air channel, and the sweep gasket section core air port; the sweep gasket section outer jacket has a bottom sweep gasket section transverse bore  174  and the gasket section transverse bore communicates with the sweep gasket section air channel and the sweep gasket section core air port. 
     Preferably, referring to  FIG. 11 , each bottom sweep gasket section  164  has at least one ferrous gasket target  154  located proximate the gasket section&#39;s top surface spaced away from the door panel jacket  104  and towards the doorframe outer jacket  46  and each ferrous gasket target aligned to cooperate and be magnetically attracted by and towards one of the electromagnets  36  when the door panel  66  is in the closed position and the electromagnets are energized. 
     Preferably, referring to  FIGS. 5A and 5B , each bottom sweep gasket section  164  has a bottom sweep gasket section loop pad  176  attached along the bottom sweep gasket section&#39;s bottom length, a bottom sweep gasket section hook pad  180  attached along an adjacent side length, and an insulating strip  173  attached along the bottom sweep gasket section&#39;s top length; the sweep gasket section loop pad having a loop pad aperture  178  and the insulating strip having an insulating strip aperture  175 , the loop pad aperture and the insulating strip aperture aligned and communicating with the sweep gasket section transverse bore  174  to allow air flow through the aligned openings. 
       FIG. 5B  shows an optional sweep gasket section end port  182  in and through the sweep gasket section outer jacket  172  that communicates with the sweep gasket section air channel  168  and the sweep gasket section end port may communicate with a corresponding intermediate gasket section end port  162  in an adjacent intermediate gasket section  148 . 
     Referring to  FIGS. 24 and 25 , preferably, there are a plurality of intermediate gasket sections  148  removably attached by attachment means respectively to at least one perimeter hook pad  146  along contiguous portions of a left periphery, a top periphery, and a right periphery of the cold space surface  108  contiguous one to another and between and contiguous to two bottom sweep gasket sections  164 . 
     In the best embodiment, see  FIGS. 4A and 4B , each intermediate gasket section  148  is an elongate insulating member having a substantially rectangular cross-section and having an intermediate gasket section core  150  made from an extruded insulating foam or some other suitable insulating material; an intermediate gasket section air channel  152  is formed substantially along the longitudinal length and the midline of the intermediate gasket section&#39;s top core surface; an intermediate gasket section outer jacket  156  substantially covers and overlays the intermediate gasket section core, and the intermediate gasket section air channel. 
     Preferably, referring to  FIG. 11 , each intermediate gasket section  148  has at least one ferrous gasket target  154  located proximate the gasket section&#39;s top surface spaced away from the door panel jacket  104  and towards the doorframe outer jacket  46  and each ferrous gasket target aligned to cooperate and be magnetically attracted by and towards one of the electromagnets  36  when the door panel  66  is in the closed position and the electromagnets are energized. 
     Preferably, referring to  FIGS. 4A and 4B , each intermediate gasket section  148  has an intermediate gasket section loop pad  158  attached along the intermediate gasket section&#39;s bottom length, an intermediate gasket section hook pad  160  attached along an adjacent side length, and an insulating strip  157  attached along the intermediate gasket section&#39;s top length. 
       FIG. 4B  shows two optional intermediate gasket section end ports  162  in and through each end of the intermediate gasket section outer jacket  156  that communicate with the intermediate gasket section air channel  152  and each intermediate gasket section end port may communicate with a corresponding intermediate gasket section end port  162  in an adjacent intermediate gasket section  148  or with a corresponding sweep gasket section end port  182  in an adjacent bottom sweep gasket section  164 . 
     Referring to  FIGS. 7-10 ,  24 , and  25 , a panel jacket side skirt assembly  116  comprises in the best embodiment a two layer fabric strip having a panel jacket side skirt loop pad  118  attached along one side. 
     In the best embodiment of a fully-assembled invention, two panel jacket side skirt assemblies  116  are removably attached respectively each to one of two panel jacket side surfaces by means of at least one panel jacket side surface hook pad  110  on each side surface engaging a respective side skirt loop pad  118 . Preferably, each side skirt loop pad  118  also engages portions of intermediate gasket section hook pads  160  adjacent a respective side surface hook pad  110  and also engages portions of a bottom sweep gasket section hook pad  180  adjacent a respective side surface hook pad  110 . 
     Referring to  FIGS. 24 , and  25 , a top skirt assembly  120  comprises in the best embodiment a two layer fabric strip having a top skirt loop pad  122  attached along one side. 
     In the best embodiment of a fully-assembled invention, the top skirt assembly  120  is removably attached to the panel jacket top surface by means of at least one panel jacket top surface hook pad  112  attached to the panel jacket top surface removably engaging the top skirt loop pad  122 . Preferably, two panel jacket top surface end hook pads  114  also engage the top skirt loop pad  122 . Preferably, each top skirt loop pad  122  also engages portions of intermediate gasket section hook pads  160  adjacent the top surface hook pad  112  and also engages portions of intermediate gasket section hook pads  160  adjacent a respective top surface end hook pad  114 . 
     Referring to  FIGS. 6 ,  9 ,  26 - 28 ,  30 ,  31 A,  31 B,  32 , and  33 , at least one and preferably two stay roller assemblies  184 , and/or  384  can adjustably assist in maintaining the door panel  66  or the leaves  220  and  224  in proximity to a nonferrous doorframe outer jacket  46  by applying adjustable pressure inwardly against a respective warm space surface  106  of a door panel jacket or a leaf jacket. A cooperating stay roller assembly  384  is a mirror version of the stay roller assembly  184 . 
     Each stay roller assembly  184  or  384  has a base plate  186 ; a spring attachment wall  188  depending upward from an edge of the base plate, a plurality of spaced spring attachment holes  190  distributed along an upper edge of the spring attachment wall; a pressure arm support post  192  depending upward from the base plate, a pivot bolt mounting bore  194  in the support post; an L-shaped pressure arm  196  having a spring adjustment leg  198  and a stay roller attachment leg  202 , a plurality of spaced spring adjustment holes  200  distributed along the spring adjustment leg, a stay roller attachment bore  204  near the free end of the attachment leg; and a transverse arm mounting bore  206  located between the two legs; a pressure arm pivot bolt  208  engaged in the pivot bolt mounting bolt rotatably mounts the pressure arm to the support post; at least one pressure spring  210  is selectively mounted between one of the spring attachment holes and one of the spring adjustment holes; at least one stay roller  214  is rotatably mounted in the arm mounting bore at the outer end of the stay roller attachment leg by a stay roller bolt  216  and a stay roller nut  218 . 
     Referring to  FIGS. 30 through 34 , an alternative flexible door panel cold storage door system  310  has a doorframe assembly  12 , having a vertical left frame  14 , a horizontal top frame  18 , and a vertical right frame  22 , mounted to or in a boundary wall  6  to contiguously define together with a floor surface between the left frame and the right frame a door opening; the left frame having a left frame core; the top frame having a top frame core; the right frame having a right frame core; each frame core having a frame core top surface and a longitudinal top surface centerline; a plurality of open electromagnet wells in the frame cores distributed along and proximate to the centerlines; a frame core ventilation channel formed in the frame core top surfaces, the ventilation channel having a first end near the left frame core&#39;s bottom end and the ventilation channel contiguously and serially communicating to and through each well in each frame core and the ventilation channel having a second end near the right frame core&#39;s bottom end; a heat dispersion layer proximately lining the wells and the ventilation channel and substantially covering the frame core top surfaces, a plurality of electromagnets operably mounted one electromagnet in each well and mounted substantially flush to the adjacent frame core top surface; a nonferrous doorframe outer jacket attached to and substantially covers the frames, the ventilation channel, and the electromagnets; each electromagnet selectively energized by a D/C power supply  38  electrically connected to the electromagnets; the power supply selectively controlled by a control box  50 ; and two air ventilation ports through the outer jacket and the ventilation ports communicating with the ventilation channel and with one port located proximate the first end and the other port located proximate the second end. 
     The alternative flexible door panel cold storage door system  310 , further has a movable flexible door panel comprising a left flexible door leaf  220  and a right flexible door leaf  224 , the leaves engageable at an abutting interface between abutting edges of the leaves, each leaf having a leaf jacket and having a leaf jacket periphery and each leaf selectively disposable against the doorframe outer jacket to at least partially block the door opening when in a respective closed position, each leaf substantially unblocking the door opening when in a respective open position; each leaf jacket having an upper end and a lower end; two bottom sweep gasket sections removably attached by attachment means one to each of the leaf jackets proximate the lower end along the leaf jacket periphery that overlaps a portion of the doorframe outer jacket when the door panel is in the closed position with one bottom sweep gasket section located proximate the first end and the other bottom sweep gasket section located proximate the second end; a plurality of intermediate gasket sections removably and contiguously attached by attachment means to each leaf jacket proximate and along a contiguous portion of each leaf jacket periphery that overlaps a contiguous portion of the doorframe outer jacket when the leaves are in respective closed positions and the gasket sections operably configured to form an air seal with the doorframe outer jacket when the leaves are in the closed position; and each gasket section having at least one ferrous gasket target located proximate the gasket section&#39;s surface spaced away from the leaf jacket and towards the doorframe outer jacket and each ferrous gasket target aligned to cooperate and be magnetically attracted by one of the electromagnets when the leaves are in respective closed positions and the electromagnets are energized. 
     In the alternative flexible door panel cold storage door system  310 , each leaf  220 ,  224  has a support frame assembly having a header spaced from and connected to at least one door panel base plate segment by at least two spaced vertical suspension cables  78 , each suspension cable threaded lengthwise through and retained respectively in one of at least two vertical tube stiffeners  86 ; at least one horizontal tube stiffener attached proximately and elastically to and perpendicularly between the two vertical tube stiffeners; a plurality of flexible insulation sheets facing one another with at least one insulation sheet on each side of the frame assembly and the insulation sheets supported by the frame assembly; the leaf jacket encapsulating the support frame assembly and the insulation sheets; and at least two door hanger assemblies  56  spaced and coaxially aligned and attached proximate the upper end to the header; an overhead horizontal track and carriage system comprising: an overhead horizontal track  254  mounted across the top frame  18 ; two carriage assemblies  352 ,  452  movably mounted to the horizontal track; each leaf suspended respectively by at least two door hanger assemblies  56  from one of carriage assemblies; and each leaf movable between the respective closed position and the respective open position; each leaf having a lower end attachment hook strip attached to, about, and encircling the lower end; each leaf having a bottom sweep assembly  324 ,  424  having a bottom sweep attachment loop strip; the respective bottom sweep attachment loop strip removably attached to the respective lower end attachment hook strip and encircling the respective lower end; a respective depending wall portion  325  of the respective bottom sweep assembly extends downward beyond the respective lower end to slidingly engage the floor surface in the door opening; the respective lower end, the respective depending wall portion  325 , and the floor surface defining a respective bottom sweep assembly air channel  344 ,  444 , and the respective depending wall portion  325  having a respective bottom sweep assembly air port communicating into and out from the respective bottom sweep assembly air channel, and the respective assembly air port aligned and communicating with one of the ventilation ports when the door panel is in the closed position; and each leaf having an interface air port  242 ,  442  in a portion of the respective bottom sweep assembly in closest proximity to the other leaf and aligned and communicating with the corresponding interface air port in the other leaf when the leaves are in the closed position. 
     In the alternative flexible door panel cold storage door system  310 , an inline ventilation fan is mounted in the ventilation channel; each leaf has a magnet strip  232 ,  234  incorporated into and along the leaf&#39;s abutting edge aligned to magnetically attract the corresponding magnet strip in the other leaf&#39;s abutting edge; and each of the leaves has a sealing flap  222 ,  226  removably attached along a portion of the leaf&#39;s abutting edge; and the sealing flaps on opposite faces of the leaves to partially overlap the other leaf when in the closed position. 
     Preferably, the left flexible door leaf  220  has a left leaf sealing flap  222  attached by cooperating hook and loop attachment pads along a portion of the left flexible door leaf&#39;s cold space surface  308  adjacent the abutting interface and extending beyond the abutting interface to partially overlap the right flexible door leaf&#39;s cold space surface  408  when the leaves are in the closed position. Preferably, the right flexible door leaf  224  has a right leaf sealing flap  226  attached by cooperating hook and loop attachment pads along a portion of the right flexible door leaf&#39;s warm space surface  406  adjacent the abutting interface and extending beyond the abutting interface to partially overlap the left flexible door leaf&#39;s warm space surface  306  when the leaves are in the closed position. 
     Preferably, the left flexible door leaf  220  has a left bottom sweep assembly  324  removably attached to, about, and encircling the lower end of the its leaf jacket; the left bottom sweep assembly having a left bottom sweep assembly air channel  344 , the left bottom sweep assembly having a bottom sweep assembly air port that communicates with a ventilation port when the leaf is in the closed position and an interface air port  242  in a portion of the left bottom sweep assembly in closest proximity to the right flexible door leaf  224  and aligned and communicating with the corresponding interface air port  442  in the right flexible door leaf when the leaves are in the closed position. 
     The right flexible door leaf  224  preferably has a right bottom sweep assembly  424  attached to, about, and encircling the lower end of the its leaf jacket; the right bottom sweep assembly having a right bottom sweep assembly air channel  444 , the right bottom sweep assembly having a bottom sweep assembly air port that communicates with a ventilation port when the leaf is in the closed position and an interface air port  442  in a portion of the right bottom sweep assembly in closest proximity to the left flexible door leaf  220  and aligned and communicating with the corresponding interface air port  342  in the left flexible door leaf when the leaves are in the closed position. 
     In the best embodiment, the frame cores  16 ,  20 , and  24  are wood, composite material, or another suitable material; the nonferrous doorframe outer jacket  46  is stainless steel, aluminum, PVC, or another suitable material; the flexible insulation sheets  72  are cross-linked polyethylene closed cell foam sheets, but could also be Minicel® foam sheets, polypropylene closed cell foam sheets, or another suitable, resilient, flexible insulation sheet known in the art that has a suitable insulating R-value. 
     In the best embodiment, the header  68  and the base plate segments  80  are made from steel channel, wood, composite material, or another suitable material; the suspension cables  78  are braided steel cables or another suitable cable and having crimped on steel cable end couplers  84  that are threaded; the tube stiffeners  86  and  94  are round or square steel tubing, round or square PVC tubing, or tubing of another suitable material. 
     In the best embodiment, the door panel jacket  104  is made of a flexible PVC, polyester, nylon, Teflon® coated, silicone impregnated, vinyl, Nomex®, Kevlar®, PBI/Kevlar®, or another suitable fabric; in the alternative embodiment having two leaves, the leaf jackets are made of a flexible PVC, polyester, nylon, Teflon® coated, silicone impregnated, vinyl, Nomex®, Kevlar®, PBI/Kevlar®, or another suitable fabric. 
     In the best embodiment, the gasket section cores  150  and  166  are made of insulating foam such as Trymer® foam, polyurethane foam, polyisocyanurate foam, polystyrene, or another suitable gasket material; and the gasket outer jackets  156  and  172  are made from a durable material such as PVC, rubber, silicone rubber, stainless steel, aluminum, or another suitable material. 
     In the best embodiment, the insulating strips  157 ,  173  can be made from neoprene or another suitable material. 
     Alternatively, the gasket sections  148  and  168  could be each made of neoprene, PVC, rubber, silicone rubber, cork, or another suitable gasket material known in the art and each gasket section incorporating at least one ferrous gasket target  154 . 
     The door system could also be configured with recessed door handles for manual operation between a closed position and an open position. 
     In the best embodiment, the door system is substantially mounted to the warm side of the boundary wall, but the door system could also alternatively be substantially mounted to the cold side of the boundary wall. 
     The preceding description and exposition of the invention is presented for purposes of illustration and enabling disclosure. It is neither intended to be exhaustive nor to limit the invention to the precise forms disclosed. Modifications or variations in the invention in light of the above teachings that are obvious to one of ordinary skill in the art are considered within the scope of the invention as determined by the appended claims when interpreted to the breath to which they fairly, legitimately and equitably are entitled.