Selas Corporation of America v Electric Furnace Co

• Jurisdiction: South Africa
• Judge: Wessels JA, Miller JA, Trengove JA, Botha JA and Galgut AJA
• Judgment Date: 22 November 1982
• Citation: 1983 (1) SA 1043 (A)
• Hearing Date: 21 September 1982
• Court: Appellate Division

Miller JA:

The appellant applied for the grant of a patent in respect of an "invention" entitled "Method and apparatus for H preventing oxidation of a metal strip during heating". The respondent opposed the application which in due course came before the Commissioner for Patents (COETZEE J) who dismissed it, with costs. An appeal was noted against the whole of the judgment and order of the Commissioner, the notice of appeal containing an allegation (the correctness of which is common cause) that the parties had agreed in writing, duly lodged with the Commissioner, that the appeal be heard not

Miller JA

by the appropriate Provincial Division of the Supreme Court but by this Court. There was also before us an application for condonation of the appellant's late filing of the notice of appeal and of the record. Detailed heads of argument in support A of the application for condonation had been served on the respondent who, while not consenting to the grant of condonation, signified that no argument against such grant would be advanced and indeed no opposing argument was presented. Mr Schreiner, for the appellant, argued the case for condonation in conjunction with full argument on the merits of B the appeal; Mr Plewman, for the respondent, confined his argument to the merits of the appeal as if the appeal were properly before us. I am satisfied that, despite the not inconsiderable delay in filing the record, this is a proper case for the granting of condonation in both of the respects mentioned - the appellant's delay, although not in all respects fully explained, is not suggestive of an intention at C any time not to proceed with the appeal, which is by no means devoid of merit; difficult questions of fact and of law could arise and what is at stake is no doubt of very considerable value and importance to the parties. And, as I have said, the respondent did not oppose the application. Condonation is accordingly granted.

D The application for the grant of the patent was made on 3 January 1974 and was based upon a prior application made in the USA on 26 October 1973. It is common cause that in terms of s 3 (2) of the Patents Act 57 of 1978 the application fell to be dealt with in terms of the Patents Act 37 of 1952 and it was so dealt with by the respondent, who opposed the grant under the E provisions of s 23 (1) of the 1952 Act, and by the Commissioner.

The fundamental purpose of the invention sought to be patented is to reduce to an effective extent oxidation of a metal strip which is undergoing a heating process calculated to fit it for being properly galvanized or annealed. It appears that it is a F common experience in the industry that when there is a "line-stop" (ie a stoppage of the movement of metal strips which are being processed) during the process of heating, oxidation of the affected strip or strips takes place. This is inimical to the success of the enterprise, for a metal strip which has suffered appreciable oxidation cannot thereafter be satisfactorily galvanized or annealed. I have advisedly used G terms of qualification when describing the purpose of the claimed invention, for although the heading of the specification of the patent speaks of "preventing" oxidation of a metal strip during heating, it appears to have been generally accepted that, while complete prevention of oxidation may be the ideal, it is not always attainable; what is sought, and H what the specification envisages, is reduction of the degree of oxidation which takes places when there has been a stoppage of the heating process to an extent which permits of production, at the end of the whole process, of a satisfactorily annealed or galvanized metal strip. In order to appreciate the true nature of the invention claimed by the appellant, it is necessary briefly to describe the apparatus and the heating process to which the invention relates.

The heating apparatus consists of two furnaces through which a strip

Miller JA

of metal passes. The first furnace has open burners which serve to heat and clean the metal; it has been described in the evidence as the "direct fired" furnace or as the "pre-heating" furnace. The burners in such first furnace may be what are called "nozzle burners", in which the mixing of the fuel and A air takes place at the point of combustion within the chamber of the furnace, or they may be "pre-mix burners", in which the mixing of the fuel and air takes place at an earlier stage with the result that the inflammable mixture as such enters the nozzles. Having passed through the first furnace, the strip of metal moves into the second, which has no open burners but is B heated by indirect means and which may be described as a heat treating chamber. Having passed through such second furnace the strip enters an area which contains the substance necessary to the galvanizing or annealing, according to requirement, of the thus treated strip of metal. The problem of C oxidation presents itself in the first furnace when, because of an emergency, there is a shutting down of the direct fired furnace, with resultant reduction of temperature and of pressure in the chamber of such furnace while the strip of metal is still within it. The effect of the sudden cooling of the furnace and the reduction of pressure therein is the entry of oxygen through openings in the furnace. The process of D oxidation of the metal strip is thereby facilitated and encouraged. The aim of the claimed invention is sufficiently to reduce the extent or degree of such oxidation.

The first (and main) claim put forward by the appellant in its application, as acceptably divided into six integers, reads as follows:

"(i)

A method of preventing oxidation of a metal strip E during shutting down a furnace chamber having a plurality of burners, the steps of which comprise;

(ii)

reducing the fuel supply to the burners from its normal supply rate to a low fuel supply rate which is much lower than the normal rate but substantially above zero;

(iii)

maitaining the low fuel supply rate substantially constant for a period of time;

(iv)

F introducing into the chamber a protective gas which is non-oxidising to the metal strip before or after reducing the fuel supply;

(v)

maintaining the feed of the protective gas and concurrently maintaining the fuel at the low fuel supply rate both for a predetermined period of time;

(vi)

thereafter shutting off the fuel supply."

G The method described in the above claim is to be found similarly described also in the consistory clause of the amended complete specification, save only that what is said in the third of the above integers is supplemented in the specification by the addition of the words "which will be determined by one skilled in the art for any particular installation" immediately after the words "... for a period H of time"; and what is said in the fifth of the above integers is supplemented in the specification by the addition of the words "which will also be determined by the requirements of the particular installation" immediately after the words "... period of time".

In its notice of opposition to the grant of the patent, the respondent listed six grounds upon...