[0001] Foam structures are known in industry and the number of applications for metallic
foam structures is continually increasing. For example, aluminium foam metal having
a continuously connected, open celled (reticulated) geometry is available and employed
in:-
a) energy/ impact absorbers;
b) heat exchangers; and
c) lightweight composite panels.
[0002] When used with heat exchangers the high surface to volume ratio allows for a compact
design and the high specific stiffness, that is, high strength to weight ratio makes
the material useful in aerospace and car applications.
[0003] Foam structures are now proposed for high pressure gas containers and in particular
high pressure gas containers having an irregular shape for example a non-cylindrical
or spherical shape. When irregular or complex shapes are required then foam material
such as metal foams are formed typically by mixing small quantities of a gasifier
e.g. titanium hydride with aluminium powder and subjecting the mixture to heat and
pressure to form a sintered sheet.
[0004] The sintered sheet or a portion thereof is then placed in a mould which is then heated
to higher temperature at which the metal melts and hydrogen is released from the titanium
hydride to provide an even dispersion of bubbles. During the foaming process a fluid
extraction tube is cast into the container and the moulded object is then allowed
to solidify and subsequently shock quenched in a cryogen, for example, liquid nitrogen.
[0005] The extraction tube normally penetrates far enough into the metal foam container
to provide a mechanically firm anchor but fluid access to it is limited by the diameter
by the extraction tube.
[0006] It is an aim of the present invention to provide at least one extraction tube for
a gas container made from metal foam which will allow the collection of gas from all
parts of the metal foam container an enable extraction to take place at faster rates
than currently are possible.
[0007] According to the present invention, a gas container made from metal foam includes
at least one extraction tube a portion of which extends into the container said portion
being formed with a plurality of perforations or slots.
[0008] In a preferred embodiment a plurality of perforated extraction tubes are provided
each being connected to a common manifold.
[0009] An embodiment of the invention will now be described by way of example reference
being made to the Figure of the accompanying drawing which is a schematic sketch of
a gas container made from metal foam including at least one extraction tube.
[0010] As shown a gas container 2 made from metal foam includes an extraction tube 4. As
illustrated, the extraction tube 4 is cast deeply into the container 2 and the portion
of the tube, where it is cast within the container 2 includes a plurality of perforations
6. The function of the extraction tube 4 with the perforations 6 is to collect and
convey gas from all parts of the container 2 and thereby enable extraction of the
gas to take place at a fast rate.
[0011] In a further embodiment the gas container 2 may be provided with two or more extraction
tubes each of which is connected to a common manifold.
1. A gas container made from metal foam material comprising at least one extraction tube
a portion of which extends into the container said portion being formed with a plurality
of perforations.
2. A gas container as claimed in claim 1, in which a plurality of perforated extraction
tubes are provided and connected to a common manifold.
