IMPROVED DOOR FRAME STRUCTURE

Abstract: A sealable frame structure for a closable opening, such as a doorway, comprises a sub-frame (1) which is adapted to be built into an opening in a wall and a frame shroud (7) adapted to be fixed to the sub-frame. The sub-frame is U-shaped in cross-section and its web is provided with a series of holes (2) by means of which the sub-frame may be secured to the wall by anchor fixings. One limb (3) of the U-shaped frame is provided with a series of holes (4) for the reception of studs (8) welded on the frame shroud (7). A strip (9) of stainless steel or like material is secured to the other limb (5) of the sub-frame by means of bolts (10) and nuts (11) and the frame shroud (7) is secured to the strip (9) by screws (12) which engage in drilled and tapped holes (13) in a strip (14) of steel. An extruded strip (15) of silicone rubber having a protruding profile (16) is fitted over an edge of the strip (9) and forms a seal with the edge of a door closing the doorway. A door is also provided having a stepped edge portion extending along its upper and side edges for engagement with the sealable frame structure.

Description: Title: IMPROVED DOOR FRAME STRUCTURE This invention relates to an improved sealable frame structure for closable openings such as a door and surrounding frame structure. In buildings used to house laboratories or other "clean" work areas in the pharmaceutical, biotechnology and allied fields, it is essential that the area be kept sterile while allowing free access for personnel. The aim of the present invention is to provide a door frame structure or other closable opening which is easy to install and provides a sterile seal for a door when closing the opening. In one aspect, the present invention provides a sealable frame structure for a closable opening, comprising a sub-frame adapted to be built into an opening in a wall and a frame shroud adapted to be fixed to the sub-frame, wherein the frame shroud is removably secured to the sub-frame and forms a gas tight seal with a closing member. Conveniently, the gas tight seal is formed by a profiled strip of yieldable material. In a preferred form the closable opening is a doorway and the closing member is a door. Preferably, the frame shroud forms a channel with the sub-frame to house electrical wire, electrical interlocks and/or indicator lights. Conveniently, a silicone rubber seal can be extended 5 across the threshold of the closable opening, to produce a gas tight seal with the closing member. In another aspect, the present invention provides a door comprising a stepped edge portion extending along its upper and side edges, wherein the wall of -the 10 stepped edge portion extending into the thickness of the door has an intumescent strip inserted into the door to form a fire seal between the door and a surrounding frame structure. In a preferred construction the door has toughened 15 plate glass windows. "1 i Preferably, the door is made of preformed stainless steel sheet material secured to a metal bracing frame. The stepped edge portion of one side of the door can conveniently be provided with two or more slots to 20 receive door hinges. Embodiments of a door frame structure and a door in accordance with the invention will -now be described, by way of example, with reference to the drawings in which:- Figure 1 is an elevation of the seal side of a sub- frame; Figure 2 is an elevation of the assembled door frame structure; Figure 3 is a cross-section taken along the line III- III of Figure 2; Figure 4 is an elevation of a door according to the invention, and Figure 5 is a cross-section taken along the line V-V of Figure 4. With reference to Figures 1 to 3, a sub-frame 1 of a door frame structure is built into a wall, not shown, during construction of the wall forming a plastering stop to ensure accurate plastering and finishing a-round the frame. The sub-frame is made of mild steel channel section and is secured to the wall through holes 2 by anchor fixings (not shown). Located down one of the sub-frame channel walls 3 are a series of holes 4 spaced at 300 mm intervals, while the other channel wall 5 (see Figure 3) has a further series of holes 6 spaced at 600 mm intervals. The upper mitred corners of the sub-frame are welded ' internally to form a rigid right angled structure. Fitted over the sub-frame 1 is a frame shroud 7 made of shaped 2 mm thick stainless steel. Welded to the shroud 7 are a number of studs 8 which on assembly of the two part frame structure are located in the holes 4. A strip 9 of stainless steel has a series of threaded studs 10 welded to it so that they locate in the holes 6 and are secured by nuts 11. The free end of the strip 9 is secured to the free end of the shroud 7 by countersunk set screws 12, which pass through holes in the shroud and are screwed into drilled and tapped holes 13 in a flat strip 14 " of mild steel. The heads of the set screws 12 are covered by an extruded strip of siliσone rubber 15 which has a protruding profile 16 to form a seal with the edge of a door closing the doorway. The edge of the strip 9 has a bevel 17 extending around the three sides of the frame structure. Similarly, one edge of the shroud 7 is turned in at 18 to provide a smooth finish with the wall of the building. When assembled the two part frame structure forms a channel 19 for electrical wiring, electrical interlocks and/or indicator lights. To assemble the frame structure, the sub-frame 1 is anchored to a wall opening via the holes 2. The stainless steel strip 9 carrying the threaded studs 10 is positioned against the wall 5 of the sub-frame locating the studs in the holes 6 in the sub-frame to which the strip is secured by nuts 11 threaded on the studs 10. The shroud 7 is located with its studs 8 in the holes 4 in the sub-frame, the free edge of the shroud being secured to the strip 9 by the countersunk set screws 12 with the interposition of the profiled siliσone rubber strip 15 covering the set screws. The frame shroud is fitted after all building construction is completed, thereby avoiding damage to the stainless steel finish of the shroud. The frame can be readily installed in new or existing structures and is equally suitable for both wet and dry constructions. The frame can be fitted with either a standard toughened plate glass or a standard stainless steel door without modification. Should the shroud be damaged during use it can be replaced without removing either the door or the sub- frame. The sealable frame structure creates a pressure joint with the surrounding wall finish to prevent the ingress of contamination to the sterile area. The frame has simple clean lines to provide easy cleaning and sterilisation for pharmaceutical and biotechnological applications as well as to provide a surface which prevents bacterial or fungal growth. In a preferred construction of the door shown in Figures 4 and 5, the door comprises a bracing angle frame 20 to which, preformed stainless steel sheet panels " 21 and 22 are spot welded. .The surrounding 5 upper and side edges of the door are stepped at 23, the inturned edge of " panel 22 is secured to panel 21 by a continuous weld 24. The wall 25 of the stepped edge portion extending into the thickness of the door has a strip of intumescent material 26 inserted into 10 the door edge to form a seal between the door and a surrounding frame structure. To enable the door to be assembled with reinforced plate glass windows 27, the bracing frame is provided with a channel section 28 to mate with the edges of an aperture in the sheet panels 15 21 and 22 forming glazing channels 29. The sheet panels 21 and 22 are removably secured together by a metal strip 30 surrounding the internal edge of the door which is secured by spot welds 31 to the panels 21 and 22. This strip is in turn 20 releasably secured by countersunk set screws to the upper bracing angle frame member 32 and the lower edge of the door 33. Two hinge slots 34 are provided in the edges of the door panels to receive hinges (not shown) . 25 Various modifications can be made to the invention, for example, a silicone rubber seal can be extended across the threshold of the door opening to produce a gas tight seal with the door forming a gas seal enabling the clean area closed by the door to be gas 30 sterilised. Although the invention has been described with reference to a door and door frame structure, it will be apparent that the opening formed by the sealable frame structure may be a window frame closed by a window or a similar closable opening which provides access to the clean, i.e. sterile area,

Claims: AMENDED CLAIMS [received by the International Bureau on 22 September 1988 (22.09.88); original claims 3,8-11 cancelled; claim 1 amended; claims 4 and 5 renumbered as 3 and 4 and amended: claims 6 and 7 renumbered as claims 5 and 6 ; claim 2 unchanged ( 2 pages ) ] 1. A sealable frame structure for a closable opening, in which the frame structure comprises a sub-frame adapted to be built into an opening in a wall and a frame shroud adapted to be fixed to the sub-frame, 5 characterised in that the sub-frame is substantially U- shaped in cross-section, the web of said U being arranged to be secured to the wall around the edges of said opening, and in that the frame shroud is fixed to the sub-frame by means of a strip of stainless steel 10 or like material which is fixed to one limb of said U- shaped sub-frame, the other limb of the sub-frame being provided with a series of holes and the frame shroud being provided with a series of studs engageable in said holes, said frame shroud forming a gas-tight seal 15 with a closing member. 2. A sealable frame structure according to claim 1, characterised in that the frame shroud forms a channel with the sub-frame to house electrical cables, electric interlocks and/or indicator locks. 3. A sealable frame structure according to claim 1 or claim 2, characterised in that the frame shroud is secured to said strip of stainless steel or like material by a series of screws. 4. A sealable frame structure according to any preceding claim, characterised in that the gas tight seal is formed by a profiled strip of resilient material fitted over an edge of said strip of stainless 5 steel or like material. 5. A sealable frame structure according to any preceding claim, characterised in that the closable opening is a doorway and the closing member is a door. 6. A sealable frame structure according to claim 5, wherein a silicone rubber seal extends across the threshold of the closable opening to produce a gas tight seal with the closing member.

Inventors: HUELIN KIRK JOHN, HUELIN, KIRK, JOHN
Applicants: HUELIN KIRK JOHN, HUELIN, KIRK, JOHN
Application year: 1988
Main classification: E06B1
IPC codes: E06B1, E06B7