The Patents Act, 1949 and Others
| Jurisdiction | England & Wales |
| Judge | LORD JUSTICE RUSSELL,LORD JUSTICE BUCKLEY,LORD JUSTICE LAWTON |
| Judgment Date | 10 May 1973 |
| Judgment citation (vLex) | [1973] EWCA Civ J0510-2 |
| Court | Court of Appeal (Civil Division) |
| Date | 10 May 1973 |
[1973] EWCA Civ J0510-2
In The Supreme Court of Judicature
Court of Appeal
Civil Division
On appeal from Order of Patents Appeal Tribunal (Mr. Justice Whitford).
Lord Justice Russell
Lord Justice Buckley and
Lord Justice Lawton
Mr. G. D. EVERINGTON, Q. C. and Mr. A. KYNRIC LEWIS (instructed by Messrs Bird & Bird) appeared on behalf of the Appellants (Applicants).
Mr. T. A. BLANCO WHITE, Q. C. and Mr. MICHAEL FYSH (instructed by Mr. J. S. Copp) appeared on behalf of the Respondents (Opponents).
This appeal with leave from the Patents Appeal Tribunal (Mr. Justice Whitford) concerns an application for a patent for a process for the production of tetrafluoroethylene (T. F. E.) by pyrolysis of chlorodifluoro-mothane (C. D. M.) with water vapour. Opposition to the application is grounded on the allegation of a prior grant (section 14(1)(c) of the statute). Specifically it is asserted that the invention so far as claimed in claim 2 of the application in suit is claimed in claim 21 of the opponents' patent 960,309. The supervising examiner concluded that prior claim was established, and this conclusion was upheld by the Patents Appeal Tribunal.
Claim 1 of the application in suit claims, in the process of manufacturing T. F. S. by pyrolysis of C. D. H., an improvement comprising the following: (i) pyrolyzing C. D. M. in the presence of water vapour, (ii) under substantially adiabatic condition, (iii) in a reaction zone having a surface-to-volume ratio of less than 130 expressed in reciprocal metres, (iv) the pyrolytic temperature of the reaction zone being produced mainly by simultaneously mixing and introducing the C. D. M. pre-heated and the water vapour superheated into the reaction zone, and (v) the proportion of water vapour being from 70 to 90 mole per cent.
Claim 2 reclaimed claim 1 but limiting the reaction zone to a tubular shape.
The surface-to-volume ratio referred to is such that if the reaction zone is a simple tubular shape the ratio requirement is met if the diameter of the tube exceeds 1.2 inches or thereabouts.
The particular inventive aspect with which this case is directly concerned is the requirement that this ratio he less than 130 so expressed.
The opponents' patent 960,309 is also for a process for the production of T. F. E. by conversion of C. D. M. by pyrolysis in a reaction zone. Claim 1 is a process for the production of T. F. E. in which a mixture of C. D. M. and the equivalent of 75 to 95 moles per cent of steam is passed through a zone in which the C. D. M. is pyrolised and the mixture is then cooled to condense the steam, "sufficient heat being contained in the pre-heated steam to bring the gas mixture to the temperature of pyrolysis and to supply substantially all the heat of the endothermic reaction".
Claim 2 narrows claim 1 by stating the moles per cent of steam as 85 to 90. Claims 3 and 4 embodied claims 1 and 2, stating the zone leaving temperature as 600 to 800 and 650 to 800 degrees Centigrade respectively. Claim 5 embodied any preceding claim but limited the pyrolysis zone to one constructed of or lined with platinum or "Inconel", the latter being the Trade Mark of a material described in the specification. Claim 6 added to any preceding claim a requirement of preheating the steam to a temperature on entering the zone of 800 to 1000° C, and claim 9 narrowed this to 900 to 1000° C. Claim 7 added to any preceding claim a requirement that "the pyrolysis is carried out substantially adiabatically in a well-lagged elongated channel, tube or duct". Claim 8 may be ignored. Claims 10 and 11 added to any previous claim the requirement that the zone entry temperature of the C. D. M. be from room temperature to 600° and from 300 to 500° respectively. Claims 12 to 16 inclusive and 19 and 20may be ignored. Claim 17 provided for the cooling of the gases leaving the zone by passage through a heat exchanger or by injecting water or cool steam or aqueous hydrochloric acid solution into the gases, or by a combination of these. Claim 18 narrowed claim 17 to a washing with a spray of water or aqueous hydrochloric acid followed by scrubbing with aqueous caustic alkali. Finally, claim 21: "A process according to any of the preceding claims and substantially as hereinbefore described, with particular reference to Examples 2 and 3".
At the outset I mention a point of construction taken by junior counsel for the appellant. Attention was drawn to the language of claim 1 of the opponents' specification, "sufficient heat being contained in the pre-heated steam to bring the gas mixture to the temperature of pyrolysis and to supply substantially all the heat of the endothermic reaction". This it is said states that the C. D. M. is to supply substantially none of the heat of that reaction. Claims 2 to 9 inclusive in effect repeat that. But claims 10 and 11 claim a process according to any of the preceding claims in which the temperature of the C. D. M. before entering the pyrolysis zone is between room temperature and 600° C, and between 300 and 500° respectively. This it was argued introduces in particular into claim 21, referring as it does to any of the preceding claims, an insoluble ambiguity. I would be unwilling to construe the claims so as to produce a conflict between claim 1 and for example claim 10 which expressly refers to claim 1, unless the language was quite clear. But here I see no conflict. I read claim 1 as being silent upon the introductory heat of that part of the gas mixture that consistsof C. D. M. I read claim 1 as if it said "and thereby to supply". I reject this point of construction.
I return to consideration of claim 21 of the opponents' specification. I observe firstly that I find nowhere in the specification any indication that any virtue is to be found in keeping the surface-to-volume ratio of the reaction zone below the figure of 130, which is the gist of the inventive improvement asserted and claimed by the applicant. Indeed, nowhere is to be found any statement from which a surface-to-volume ratio of a reaction zone is capable of calculation save in Example 2 and Example 3.
Page 5, line 100, says: "Our invention is illustrated by the following Examples 2 and 3, in comparison with Example 1 in which heat was applied to the mixture across the walls of the reactor so that the pyrolysis was not substantially adiabatic". Example 1 is of no assistance. Example 2 - which is so labelled as a single example of "our invention" and not a series of examples thereof - described, inter alia, the reaction zone or vessel as 48 inches long with 1 inch internal diameter. Calculation shows this to have a surface-to-volume ratio of over 130. Example 2 then stated the data and results, various measurements of temperature, etc., having been made. Twenty-four "results of this example" were set out. In each case flow rates of C. D. M. and steam were measured from which dilution ratios were calculated varying from 5.1 to 25.2 (compare 7 to 9 in the applicants' claim and 3 to 19 in the opponents' claim 1: three out of the 24 were within the 7-9 bracket and two outside the 3-19 bracket). Steam inlet temperatures varied from 850° C to 970° C (compare opponents' claim 1 "sufficientheat", claim 6 800 to 1000° C, claim 9 900 to 1000° C). C. D. M. inlet temperatures varied from 295° to 520° C, ignoring a queried figure of 25° (compare opponents' claim 10, room temperature to 600° C, and claim 11, 300° to 500° C). Example 3 - again a single example or illustration of "our invention" - stated also data and results of experiments. The reaction zone used was described as tubular, being 31½ inches long and 6 inches in diameter: this gives in fact a surface-to-volume ratio less than 130. There were 17 recorded experiments in this example. The dilution ratio calculated from flow rates varied from 9.6 to 6.6, four (numbers 5, 7, 9 and 10) being within the applicants' claim bracket of 7 to 9 and five others less than 0.1 above that bracket. Example 3 also gave steam and C. D. M. inlet temperatures, the latter on the whole markedly below those in Example 2 because of loss of heat in piping from the heating source to the reaction vessel. Other results are given in terms of efficiency loss in each experiment and analysis of gaseous products of each experiment.
As appears from the above, none of the experiments in Example 2 relate in any way to the applicants' claim 2 because the reaction vessel, though tubular, had a surface-to-volume ratio above 130. But in Example 3 the tubular reactor ratio was in fact less than 130 and in four experiments strictly within the applicants' 7-9 bracket dilution ratio.
Claim 21 is a claim to an invented process with particular reference to Example 3 which is an illustration of "our invention". On its true construction, does it claim that which is claimed by the specification in suit? In my view, it does not. It seems to me that the claim, in so far as itcan be said to incorporate a claim to that illustration of the invention which is found in Example 3, must be a claim to the whole of what is found in Example 3. If it may be regarded at all as a claim to a process of which a significant feature is that the reaction chamber has a surface-to-volume ratio of less than 130, it must nevertheless be regarded as a claim to a process which permits a dilution ratio in a bracket from 6.55 to 9.60, whereas the invention which is claimed by the applicants involves a bracket limited to 7 to 9, or (in the applicants' claim 5) 7.5 to 8.5.
It seems to me that on this short ground it can be said that the invention so far as claimed in claim 2 of the...
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