Metal working – Method of mechanical manufacture – Combined manufacture including applying or shaping of fluent...
Patent
1992-10-28
1995-03-14
Fiorilla, Christopher A.
Metal working
Method of mechanical manufacture
Combined manufacture including applying or shaping of fluent...
264154, 264316, 296235, 29428, B23P 1100, B28B 148
Patent
active
053966945
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of manufacturing a graphite foil coating for use in an alkali metal energy conversion device, in particular, a method for manufacturing a graphite foil coating for the reservoir which holds the molten alkali metal in a sodium sulphur cell.
In a sodium sulphur cell, for example, a solid electrolyte material, typically beta alumina, separates molten sodium, constituting the anode, from the cathodic reactant comprising molten sulphur and sodium polysulphides. In a device such as that described in WO 89/05527 the molten sodium is held in a reservoir of very thin mild steel. The outer surface of the mild steel is then coated with graphite foil to provide protection against corrosive attack by any sodium polysulphides appearing in the space between the reservoir and the solid electrolyte in the event of failure of the electrolyte. However, since the reservoir is made from a very thin mild steel the problem is one of how to apply a graphite foil (or graphoil) coating without damaging the reservoir. In order to prevent the reservoir from crushing under the external pressure it has been known to pressurize the interior of the reservoir at the same time as the coating is pressed onto the reservoir but this method is by no means satisfactory.
Accordingly, the present invention provides a method of manufacturing a graphite foil coating for use in an alkali metal energy conversion device wherein the coating is prepared prior to location on the component to be coated by isostatic pressing of graphite foil in a molding apparatus.
Preferably, the coating is made by molding separate pieces which when located over the component to be coated provide a continuous coating.
Preferably, the coating pieces are made by placing a sufficient quantity of graphite foil within a bowl to line the interior of the bowl and then applying the isostatic pressure to bond the graphite foil to itself to form a coating piece of conformal shape to the surface it is to coat.
Preferably, the coating pieces are made by placing a sufficient quantity of graphite foil over a mandrel and then applying isostatic pressure to bond the graphite foil to itself to form a coating piece of conformal shape to the surface it is to coat.
Preferably, the isostatic pressure is applied by locating a pressing bag of polyurethane over the graphite foil and placing the arrangement within an isostatic press.
Preferably, the graphite foil coating is then applied to the outer surface of the reservoir which holds the molten sodium metal in a sodium sulphur cell.
Preferably, the graphite foil coating is made by isostatic pressing of graphite foil to form upper and lower graphite foil cups for location on the upper and lower portions of the reservoir.
Preferably, one of the graphite foil cups is provided with a rim for engagement with the other graphite foil cup.
Preferably, the upper and lower graphite foil cups are provided with a hole substantially in the center of the base portion of the cup.
Preferably, a hole is pre-cut in a disc of graphite foil and there is a nipple over which the disc is placed either in the base of the bowl or on the tip of the mandrel.
Preferably, a hole is made by providing a hole either in the base of the bowl or on the tip of the mandrel such that when the graphite foil is isostatically pressed a hole will be formed in the graphite foil.
A preferred embodiment of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawings, of which:
FIG. 1 is a view in cross-section of a typical sodium sulphur cell which could incorporate a graphite foil coating in accordance with the present invention;
FIGS. 2 and 3 are cross-sectional views of the apparatus used to form the top and bottom graphite foil coating cups for the reservoir of a sodium sulphur cell similar to that in FIG. 1;
FIG. 4 is a cross-sectional view of a mandrel and corresponding isostatic pressing bag used to form a coating for the reservoir of a sodium sulphur cell similar to that in FIG.
REFERENCES:
patent: 3265798 (1966-08-01), Lyle, Jr.
patent: 3502759 (1970-03-01), Olstowski et al.
patent: 4000235 (1976-12-01), Van Leemput
patent: 4220691 (1980-09-01), Roth et al.
patent: 4265952 (1981-05-01), Caines
patent: 4395810 (1983-08-01), Tsuzawa et al.
Fiorilla Christopher A.
Silent Power GmbH fur Energiespeichertechnik
LandOfFree
Method of manufacturing a graphite foil coated reservoir does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing a graphite foil coated reservoir, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing a graphite foil coated reservoir will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-706559