The present invention relates to a plug for sealing holes in structures such as fluid containers, and is particularly directed to a plug for aircraft fuel tank sealing.
Current devices to plug normal structural holes in integral metal fuel tanks requires the time consuming installation of a mechanically attached mesh screen patch overcoated with a sealant. However, securing the screen patch in corners and other relatively inaccessible locations is tedious and expensive from a labor time aspect.
The prior art discloses various types of plug for sealing purposes. U.S. Pat. No. 2,739,352, for example, discloses a plug for tire repairing having a stem on which are formed a plurality of like tapered fins. Prior art plugs of this general type are used for plugging leaking tires against a rubber structure, not a metal structure, and they seal against pressurized air, not a liquid such as a liquid fuel.
U.S. Pat. Nos. 4,058,234 and 4,160,465 are exemplary of prior art plugs used for sealing leaking containers. U.S. Pat. No. 4,058,234 uses elaborate equipment to pump foam into a sponge to seal a hole in a ruptured container. U.S. Pat. No. 4,160,465 utilizes a porous fabric bag filled with powder that swells when placed in contact with water, as a temporary plug for a leaking hole in a water tank. These plugs, however, are not feasible or practical for use in sealing fuel tank holes.
It is an object of the present invention to provide an improved reliable plug for sealing holes in metal containers.
Another object of the invention is the provision of a plug of the above type which is simple in design, is relatively inexpensive and which is readily manipulated to plug a hole in a metal structure.
Yet another object is to provide a plug of flexible resilient material for use in sealing holes in metal aircraft fuel tanks, e.g. irregularly shaped holes, holes resulting from structural joints and holes of various sizes, while resisting the corrosiveness of the fuel.