Patent Application
20090029643
1. Field of the Invention
This invention relates to structures, and in particular to a pressure relief valve for structure.
2. Background of the Invention
A common destruction sequence for building structures during windstorms such as hurricanes and tornadoes involves the following steps: 1. An opening such as a window or door is blown in on the upwind side of the structure; 2. The pressure of the air inside the building rises due to strong wind entering the breached opening; and 3. The internal air pressure literally blows the roof off of the structure. In the case of a tornado, the building actually explodes due to the sudden pressure differential of air trapped inside vs. the greatly reduced air pressure outdoors as the tornado approaches closely.
In this scenario, severe building damage results, clearly from the loss of the roof itself, but also from the ensuing water damage caused by the frequently torrential rain which falls directly into the structure. The problem of wind damage to buildings will probably get worse in the future, due to the natural hurricane cycle, which is currently on the ascendancy, and also due to increased storm strength due to global warning.
Thus, it would be desirable to provide a means of relieving the internal pressure of structures during wind storms, so as to avoid blowing their roofs off.
Existing Designs
A number of approaches have been hazarded to address this problem. U.S. Pat. No. 6,484,459 was granted Platts for a counter-pressure method which involved installing a number of window and door valves to relieve interior pressure. While this approach apparently relieved inside pressure, it was cumbersome to install the requisite valves at various locations in the structure to be protected, was very slow for tornados, and lacked the very high quality flow required for timely pressure equalization.
U.S. Pat. No. 7,001,266 was granted Jones et al. for a rooftop vent, which was designed to reduce inside pressure. This vent was permanently open, and appeared to suffer from the disadvantage that rain could enter the structure, given sufficient wind.
U.S. Pat. Nos. 6,206,774, 6,558,251 and 6,293,862 issued to Dexter et al., Sells and Jafine et al. respectively, for roof vents. While these designs appeared capable of relieving pressure internal to a building, no means for doing so on the down-wind side was taught, because these valves could not change their angle relative to the roof upon which they were mounted.
Accordingly, it is an object of the present invention to provide a pressure relief valve for structure which is capable of instantly relieving windstorm-induced pressure interior to a structure. Design features allowing this object to be accomplished include a plurality of springs urging a valve into a valve seat, the springs being sized to permit the valve to open when a pre-determined pressure differential between air pressure exterior to the structure and air pressure interior to the structure has been reached, e.g. 1.5 pounds per square inch (“psi”). Benefits associated with the accomplishment of this object include reduction of the possibility of the roof being blown off the structure due to windstorm-induced pressure interior to a structure, and the attendant cost savings in repair.
It is another object of the present invention to provide a pressure relief valve for structure which is normally closed. Design features allowing this object to be accomplished include a plurality of springs urging a valve into a valve seat. Advantages associated with the accomplishment of this object include reduced entry of precipitation, and reduced attendant water damage to the structure.
It is still another object of this invention to provide a pressure relief valve for structure whose up-wind side will tend to remain closed while its down-wind side opens to relieve pressure interior to a structure. Design features enabling the accomplishment of this object include a valve having spoiler along its edge(s), which spoils the smooth airflow like ice on an airplane wing destroys lift, thus causing the storm wind itself to urge the valve upwind side to remain closed.
Advantages associated with the realization of this object include less entry of wind-driven precipitation into the structure (because the valve opens for only seconds in a tornado), and the associated reduced water damage and lower cost of repair.
It is another object of the present invention to provide a pressure relief valve for structure which may be installed in a single location. Design features allowing this object to be accomplished include a valve seat disposed around a building valve aperture, and a plurality of springs urging a valve into the valve seat. Benefits associated with the accomplishment of this object include instantaneous speed, simpler and lest costly installation, better reliability, and reduced maintenance cost.
It is still another object of this invention to provide a pressure relief valve for structure which may be secured in place using a single cable. Design features enabling the accomplishment of this object include a single cable entering and exiting a valve seat and valve through a plurality of springs. Advantages associated with the realization of this object include simpler construction, along with the associated reduction in cost.
The invention, together with the other objects, features, aspects and advantages thereof will be more clearly understood from the following in conjunction with the accompanying drawings.
Five sheets of drawings are provided. Sheet one contains
Referring now to
Referring now to
Spoiler 15 is disposed around the edge of valve 2, and serves to spoil the smooth airflow, like ice on an airplane wing destroys lift, thus causing the storm wind itself to urge the upwind side of valve 2 to remain closed. In
Although in the preferred embodiment the cross-sectional shape of spoiler 15 was round, as depicted in FIGS. 1 and 3-8, it is intended to fall within the scope of this embodiment that spoiler 15 be any appropriately shaped spoiler disposed around the edge of valve 2.
Even if the upwind side of valve 2 were to rise, thereby admitting storm wind 14, the downwind side of valve 2 would open (or remain open), thereby allowing storm wind 14 to escape structure 4 as escaping air 18. In this case, valve 2 would elevate above valve seat 3 as indicated by arrow 28 in
As may be more clearly observed in
Spring 22 is sandwiched between spring stop 24 at a lower end of spindle 26, and structure 4. Spring 22 may be pre-loaded so as to urge valve 2 into contact with valve seat 3, as indicated by arrow 42 in
An alternate embodiment could place spring 22 between spindle stop 40 and valve 2, in which case spring stop 24 would be sized to be larger than structure spindle aperture 36, thus preventing the end of spindle 26 to which spring stop 24 is attached from sliding through structure spindle aperture 36. Spindle 26 could be any appropriate elongate member, including but not limited to cable, chain, a metal or synthetic rod, a bolt, etc.
In the preferred embodiment, spring assemblies 9 were spaced 12 inches apart. Valve 2 was made of aluminum, metal, synthetic, concrete, or other appropriate material, and skylight 12 was made of glass, plastic, or other appropriate transparent material. Spindles 26 were any appropriate elongate member, including but not limited to cable, chain, a metal or synthetic rod, bolt, etc. Springs 22 were commercially available compression springs. Cable stops 33 and washers 35 were commercially available components. Spindle stops 40 and spring stops 24 were metal, synthetic, or other appropriate material.
While a preferred embodiment of the invention has been illustrated herein, it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit of the appending claims.
