Explosion-suppressive masses

DETAILED DESCRIPTION Applicant has found that the filler masses formed of multiple layers of expanded metal are often of unduly high bulk density.
In particular when, in the course of an economical manufacturing method, coiled bales are formed by coiling expanded aluminum foil of the mesh and strand dimensions specified in the above-mentioned patent, the bales obtained typically have a bulk density somewhat in excess of the value of 52.
4 kilogram per cubic meter which is recommended in the above patent.
It is desirable that the bulk density should be kept low so as to minimize the cost of the filling, and the weight that it adds, as well as the reduction in capacity that results when the bale is fitted into a gas tank.
Further, the filler masses tend to be of uncontrolled variable density as they are susceptible to compaction under pressure, so that the eventual bulk density may tend to vary as a result of pressures applied to the mass during manufacture or in subsequent handling or in the course of placing and positioning the masses within the fuel or other containers.
In accordance with the invention, filler masses which have stabilised reduced bulk densities, can be obtained by arranging the successive layers of expanded metal in such fashion that the inclining mesh strands in each layer are directed oppositely to the mesh strands in the adjacent layers.
Whereas if similar layers of expanded metal are laid directly one on top of another with the edges of the successive layers in register, the layers tend to nest closely together, to a degree dependent on the pressures applied to the masses, when the layers are arranged so that the mesh strands in adjacent layers are oppositely directed, the oppositely inclining mesh strands engage together in such manner that the layers are more widely spaced, giving a more springy, resilient filler mass of reduced bulk density, which does not tend to become permanently compacted.
Further, applicant has found that in the process of composing or compiling the expanded metal layers together into a multiple layer mass, the successive layers may become slightly displaced one from another in the same transverse direction as a result of the nesting mentioned above, with the result that the completed filler mass has sloped end faces