Vapor-tight thermal insulating door

Claim 1

AN EXPLOSION-PROOF DOOR STRUCTURE FOR AN OPENING IN A METAL WALL COMPRISING, A DOOR FRAME FOR BORDERING THE WALL OPENING ON THE OUTER SIDE OF THE WALL AND HAVING A FRAME FLANGE EXTENDING OUTWARDLY FROM THE WALL, A DOOR COMPRISING A RECTANGULAR FIRST DOOR PAN OF RELATIVELY THICK SHEET METAL AND HAVING AN OUTER DOOR FLANGE DEFINING AN INSIDE CORNER AND EXTENDING INWARDLY TOWARD THE WALL IN THE CLOSED POSITION OF THE DOOR, SAID DOOR FLANGE BEING RECEIVABLE IN SURROUNDIN RELATIONSHIP OVER SAID FRAME FLANGE IN THE CLOSED POSITION OF THE DOOR, GASKET MEANS CONTINUOUSLY EXTENDING ALONG THE INSIDE CORNER OF SAID FIRST DOOR PAN, AN ELEMENT OF SAID GAS KET MEANS SEALINGLY RECEIVING THE OUTER EDGE OF SAID FRAME FLANGE WHEN THE DOOR IS CLOSED, AND A SECOND DOOR PAN OF RELATIVELY THIN SHEET METAL EXTENDING FROM THE INSIDE BOTTOM WALL OF SAID FIRST DOOR PAN INTO THE WALL OPENING IN THE CLOSED POSITION OF THE DOOR, SAID PAN CONTAINING HEAT INSULATING MATERIAL AND BEING SPACED BY AN ELEMENT OF SAID GASKET MEANS FROM FACE-TO-FACE HEAT-TRANSFERRING CONTACT WITH THE FIRST DOOR PAN.