Movable or removable closures – Closure seal; e.g. – striker gasket or weatherstrip – Inflatable or fluid pressure responsive
Reexamination Certificate
1998-06-29
2001-03-06
Redman, Jerry (Department: 3634)
Movable or removable closures
Closure seal; e.g., striker gasket or weatherstrip
Inflatable or fluid pressure responsive
Reexamination Certificate
active
06195941
ABSTRACT:
SPECIFICATION CROSS REFERENCE TO RELATED APPLICATIONS
This application is a national stage of PCT/EP97/03787 filed Jul. 15, 1997 and based upon German national application 196 28 747.2 of Jul. 17, 1996 under the International Convention.
FIELD OF THE INVENTION
The invention relates to a safety door, particularly a sterile door, for an access opening to a safety room and particularly to a sterile room, which has a surrounding frame and a single-leaf door connected to the frame by means of door hinge plates, as well as a pressure-actuated sealing system, which can be activated and deactivated. Such a safety door, particularly a sterile door, serves for closing off safety or sterile areas. These can be areas free of pathogenic agents, e.g. SPF animal containment areas, cell and tissue cultures, whereby positive room pressure is used to exclude the ubiquitous germs, or infectious media (viruses, bacteria, fungi, yeasts, spores, etc.) and negative room pressure is used for preventing the contamination of surrounding areas. Safety and sterile doors can also be typically used for closing off biological and genetic engineering safety areas, as well as physical and chemical safety areas. Biological and genetic engineering safety areas have to be closed off to exclude ubiquitous germs. Physical safety areas, for instance radionuclide areas, have to be closed off in order to prevent a contamination of the environment through transmission by air and nuclide entrainment. In gassing chambers and spaces the aim is to protect the environment against the escape of noxious gases, while in the case of disinfection chambers and rooms the environment has to be protected against the escape of disinfectants. Chemical safety areas, for instance, require the prevention of the escape of miasma and olfactory irritants. It is self-understood that the door frame comprises a door header, door jambs and a door threshold. The door frame is connected with the respective room wall, which preferably is a lightweight construction wall, because in sterile areas multiple metal walls are built in a sandwich manner.
BACKGROUND OF THE INVENTION
There are several known safety doors. From practice particularly one embodiment is well known wherein the door leaf carries, along its door-leaf edge facing the frame, a surrounding hollow sealing profile pertaining to the sealing system is attached to the door leaf. The hollow sealing profile is not a hose seal, if under hose seal one understands a seal having a round or rectangular hose cross section and which can be inflated. In the known sealing profile a longitudinally running groove with an M-shaped cross section is provided, which under the influence of the pressure medium causing the sealing is folded forwards and lodges in an assigned depression, and which during pressure relief folds inwards and withdraws. When under the influence of the pressure medium, such a hollow sealing profile produces only minimal restoring forces, which means that during pressure relief the restoration is correspondingly slow. In the case of safety doors it is also known to work with inflatable hose seals which have a basically rectangular cross section. This hose seal is inserted in a corresponding groove on the door-leaf edge. In the inflated state the hose seal develops a projection which engages in a corresponding depression, thereby causing a form-fitting lock. This system can have fitting problems, because the depression is in the frame and, in the case of a deficient fit, functional impairment and particularly defective sealing can occur. Regarding the completion of the seal, as well as the pressure relief and thereby the opening of the door, relatively long periods of time have to be expected.
OBJECT OF THE INVENTION
It is the object of the invention to provide a safety door, particularly a sterile door, with remarkable simplicity and functional safety, which in particular avoids fitting problems and insures that the completion of the seal, as well as the pressure relief and thereby the door opening take place in very short time intervals.
SUMMARY OF THE INVENTION
This object is achieved in a safety door, particularly a sterile door for openings allowing access to safety rooms, respectively sterile rooms, which has a surrounding door frame and a single-leaf door connected to the door frame by door hinges, as well as a pressure-actuated sealing system which can be activated and deactivated. According to the invention
1.1) the grooveless door leaf carries at its door leaf edge facing the grooveless door frame a surrounding hose-type seal made of rubber or plastic material, which is part of the sealing system and is sealingly attached to the door leaf and which is inflatable with predetermined sealing force against an autogenic restoring force,
1.2) the frame surface facing the hose-type seal is a flat nondeformable sealing countersurface against which the inflated hose seal presses sealingly when the door leaf is closed and the sealing system is activated, and
1.3) the sealing system is automatically controlled and has a source of compressed air, a compressed-air duct system and pressure-relief system with control valves, by means of which the hose-type seal can be inflated when the sealing system is activated, and when the sealing system is deactivated the hose-type seal can be deflated via these components.
The source of compressed air, the compressed-air duct system and the cross section of the compressed-air inlet can be so arranged that the sealing force additionally locks the closed door leaf quickly and securely against the frame via frictional engagement. The pressure-relief system and the cross section of the compressed-air outlet of the hose-type seal are so arranged that the door leaf locked by frictional engagement is unlocked in a pressure-relief interval of 1 to 6 seconds, preferably 1 to 3 seconds.
The invention is based on the concept that when using a hose-type seal designed to work with corresponding pressures, it is possible to dispense with the form-fitting lock between the door leaf and the door frame with the help of the sealing profile, when the sealing force is selected and set so high that locking can be achieved through frictional engagement. This avoids fitting problems and the resulting disadvantages. Based on the fact that very high pressures of the pressure medium, and thereby very high sealing forces are used it is possible at the same time to achieve extremely short time intervals for the sealing and the therewith connected locking, and also to achieve extremely short intervals for the pressure relief of the hose seal and for the opening of the door. The extremely quick locking and opening of the door leaf is optimized since sufficiently large cross sections for the compressed-air inlet and the compressed-air outlet are selected for the hose-type seal. High pressures of the pressure medium, which can consist not only of compressed air but also of another gas, mean pressures of for instance 3 bar and more. For the purpose of sealing, it is sufficient to bring the door leaf in position whereupon it locks automatically, whereby the positioning is tested via an electric proximity switch, e.g. a reed contact. The simple handling of the opening via an electric push-button and of the sealing of the door leaf by simply closing the safety or sterile door without any further manual actuation, insure that the door leaf remains locked also during multiple use and does not remain open between operations. The pressure-relief system can be provided with an emergency unlocking device for dangerous situations, which could be located for instance on the wall close to the door frame and by means of which the door leaf can be opened independently of the electronically controlled sealing system.
The door leaf and the surrounding door frame can advantageously have mutually corresponding rounded corners, in order to achieve a perfect seal between the sealing countersurface and the hose seal also in the corner areas. The rounding of the frame corners can be done with correspon
Burow Kurt
Kirschning Werner
Lass Horst
Rekowski Peter
Steppke Dieter
Dubno Herbert
Redman Jerry
Solvay Pharmaceuticals GmbH
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