US 7195032 B2
The invention provides a flap valve for controlling the air pressure within a protected space defined by walls, the flap valve including a valve frame attachable to an opening made in the walls, a valve flap, articulated at least indirectly to the frame and being subjectable to both a sealing force which forces the valve flap against the valve frame and to an opening force which lifts a portion of the flap off the valve frame; the flap valve having a first position in which the protected space is sealed off from a contaminated environment, and a second position in which air from the protected space is allowed to escape into the environment via the opening, wherein the sealing force is constituted by at least one spring at least indirectly attached to the valve flap and the valve frame.
1. A flap valve for controlling the air pressure within a protected space defined by walls, said flap valve comprising:
a valve frame attachable to an opening made in said walls,
a valve flap, articulated at least indirectly to said frame and being subjectable to both a sealing force which forces said flap against said valve frame and to an opening force which lifts a portion of the flap off said valve frame;
said flap valve having a first position in which said protected space is sealed off from a contaminated environment, and a second position in which air from said protected space is allowed to escape into said environment via said opening;
at least one spring at least indirectly attached to said valve flap and said valve frame and located in a plane substantially parallel to the plane of said valve frame, and bent leaf spring extending along one surface of said flap and affixed at one end to said flap while freely bearing against the flap at its other end, and a slider coupled to a slot in the frame and movable along said bent leaf to vary the opening force applied to the surface of said flap.
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The present invention relates to a valve for controlling the air pressure within a protected space defined by wall surfaces. More particularly, the invention relates to a flap valve to be used in a structure for preventing the penetration of contaminated air and/or gases, liquids or aerosols, and for controlling air pressure within such a protected space.
As is known, there is an increasing need for protection against the penetration of contaminants into a sheltered space, given the threat of military attacks and acts of terror using nuclear, chemical or biological (NBC) means of warfare. Such protection is provided by the use of shelters and protected spaces located inside buildings (“hard” shelters), or tent structures (“soft” shelters). Hard shelters are provided with professional NBC air filtration systems including blowers, which create an overpressure inside the protected space and provide cleaned and filtered air. The overpressure is required in order to ensure a clear direction of airflow from inside the protected space to the outside atmosphere, through ever-present leaks in the walls of the shelter, the door and the window seals. Use of this method makes sure that no contaminated air will penetrate into the protected space.
In a typical soft-type shelter, clean, NBC-filtered air is pushed by blowers into the tent, with excess air passing to the outside through leaks or specially created holes in the walls of the tent. The disadvantage of such an arrangement is that, during times when no fresh air is pumped into the protected space, e.g., during a blower breakdown, the essential overpressure immediately drops, with two dire results: contaminated air can enter the protected space via the air exit holes, and, if the protected space is in fact an inflated structure, the internal liner bubble may collapse, trapping inside all of the persons and goods to be protected. If these structures had closable valves, none of the above failures would be able to occur and the system would remain intact for a prolonged period of time until the clean air supply resumes and creates the required overpressure.
It is therefore a broad object of the present invention to provide both hard and soft protected shelter structures with valves for controlling air pressure that are reliable, inexpensive and easily installed.
It is a further object of the present invention to overcome the disadvantages of the fresh-air supplied prior-art protected spaces and structures, and to provide such structures with valving arrangements that will either act as safety valves to protect the space against excessive overpressure, or to close off the protected space in the event of an air supply system failure until sufficient pressure has been rebuilt, or to operate as simple non-return valves.
The terms “protected space” and “structures” used herein are meant to encompass all types of such spaces and structures, including vehicles which may provide shelters against NBC attacks.
According to the invention, the above objects are achieved by providing a flap valve for controlling the air pressure within a protected space defined by walls, said flap valve comprising a valve frame attachable to an opening made in said walls, a valve flap, articulated at least indirectly to said frame and being subjectable to both a sealing force which forces said valve flap against said valve frame and to an opening force which lifts a portion of the flap off said valve frame; said flap valve having a first position in which said protected space is sealed off from a contaminated environment, and a second position in which air from said protected space is allowed to escape into said environment via said opening; wherein said sealing force is constituted by at least one spring at least indirectly attached to said valve flap and said valve frame.
The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures, so that it may be more fully understood.
With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
In the drawings:
Referring now to the drawings,
The flap valve 2 is composed of a frame 6 and a flap 8. The frame is made with flanges 10, whereby the frame is attached to the wall of the structure by means of bolts and nuts 12. If the wall is made of a plastic material, attachment may be effected by ultrasonic welding, or by other joining methods, e.g., gluing.
As further seen in
A first embodiment of the articulation of the flap valve 2, seen in
A second embodiment of the flap valve 2 for controlling the air pressure within a protected space, is illustrated in
The valves according to the present invention thus have three modes of operation:
Since the valves of the present invention have the characteristics of providing constant overpressure, e.g., 300 to 320 Pa, it can be used in shelters and vehicles, as it opens only when the preset pressure value is reached and not earlier. Any leakage of the protected space is therefore limited to that of real leaks.
With the utilization of the embodiments described hereinbefore, the following specific operation features can be achieved:
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.