T 0837/00 15-01-2004

1. The appeal is admissible.

Main request

2. Amendments

2.1. Compared to the claims as granted, only Claim 1 has been modified, by deletion of the contested feature "no more than about 3,500 litres/hr".

2.2. Since that amendment is occasioned by the ground of opposition under Article 100(c) EPC, it complies with Rule 57a EPC.

2.3. The feature added during the examination proceedings has been deleted from Claim 1. Therefore, the question whether or not the deleted feature has a basis in the application as filed has become irrelevant and a contravention of Article 123(2) EPC can no longer be alleged.

2.4. It remains to be decided whether or not the deletion of that feature extends the scope or protection of Claim 1 as granted, as objected to by the respondents.

2.4.1. The feature added to the preamble of Claim 1 in suit during the examination proceedings, concerning a throughput of permeate, was a technical feature not disclosed in the application as filed.

2.4.2. That feature in the preamble of Claim 1 defined an upper limit for a flow-rate of the permeate in a single pass. However, also the feature of the first clause of the characterising portion of Claim 1 defines an upper limit for the flow-rate of the same permeate. Hence, in Claim 1 as granted, one and the same flow-rate was defined by two maxima under the same condition. Therefore, a contradiction was evident.

2.4.3. A contradiction is however a matter of clarity, on which there are no grounds for opposition (Article 100 EPC). In order to resolve that contradiction, Claim 1 has to be interpreted.

2.4.4. Claim 1 concerns a self-contained transportable reverse osmosis water purification unit as delineated in its preamble. That unit further comprises the features of the characterising portion of the claim.

2.4.5. According to the description of the patent in suit, in particular the "Summary of the Invention", the unit should be capable of producing no more than 20 gpm of potable permeate (Column 6, lines 8 and 9).

That throughput constitutes a maximum throughput of permeate sought for the claimed units, as it is apparent from several other parts of the description (column 1, last line; column 7, lines 16 and 37; column 11, lines 19 and 55; column 12, line 41). That maximum throughput is defined in the first clause of the characterising portion of Claim 1 in suit.

2.4.6. The contested maximum flow-rate of "3 500 litres/hour", now cancelled from the preamble of Claim 1, is smaller than the maximum flow-rate of permeate of 20 gpm defined in the characterising portion of Claim 1 in suit, whichever factor of conversion to litres is used for the unit gallon.

Since the maximum flow-rate of 20 gpm of permeate in a single-pass is defined as an essential feature of the invention throughout the description and in the first clause of the characterising portion of Claim 1, the specification as a whole shows that the cancelled smaller maximum of 3,500 litres/hr is not intended to limit the throughput of permeate in a single pass.

2.4.7. Furthermore, the cancelled feature had been taken from D1 and inserted in the preamble of Claim 1. The features of the preamble of a claim drawn-up in a two-part form, pursuant to Rule 29(1) EPC, shall define the features of the invention, which, in combination, are part of the prior art, whereas the characterising portion shall state the additional features which, in combination with those of the preamble, it is desired to protect. It is true that the fact that a feature in the preamble recurs in the characterising portion in a modified form is an example of an incorrect claim drafting. It is however neither a rare exception (Bruchhausen, Die Formulierung der Patentansprüche und ihr Auslegung, GRUR 1982, 1, at page 4, left column) nor does it make impossible an appropriate understanding of the claim. It remains clear that the preamble is related to the state of the art and that the characterising part contains the distinguishing features. Therefore, the structure of Claim 1 confirms that the cancelled feature was not intended to restrict the claimed subject-matter.

2.4.8. Hence, Claim 1 as granted contained a feature not originally disclosed which, however, did not limit the maximum throughput of permeate.

2.5. It follows from the above that the deletion of the added feature "no more than about 3,500 litres/hr" does not result in an extension of the protection conferred beyond the maximum value specified in the characterising portion of Claim 1 as granted.

2.6. Therefore, Claim 1 as amended according to the main request fulfils the requirements of Article 123(3) EPC.

3. Correction under Rule 88 EPC

3.1. The further relevant question to be answered is whether or not the correction of the conversion factor from gallon to litre resulting from Claim 1 as filed complies with the requirements of Rule 88 EPC, thus with those of Article 123(2) EPC.

3.2. Rule 88, second sentence, EPC includes two requirements:

(a) the first requirement is that it must be objectively recognisable that specific information is incorrect, i.e. the skilled person must be in a position to objectively recognise the incorrect information by using common general knowledge.

(b) the second requirement is that it is immediately obvious to the skilled person that nothing else had been intended than the proposed correction. In that respect, the incorrect information can be corrected only within the limits of what the skilled person, using common general knowledge, would directly and unambiguously derive from the description, claims and drawings, if any, of the European patent application, seen objectively and in relation to the date of filing, i.e. what was, on the date of filing, the objectively recognisable intention of the person making the request (G 11/91, OJ 1993, 125, point 2 of the reasons; Case Law of the Boards of Appeal of the EPO, 4th edition 2001, III.D.2, III.E).

3.3. Claims 1 (four times) and 7 (once) as filed add a conversion from the original units "gallon" and/or "gpm" to the SI units "litres" and "litres/hr", respectively, in order to indicate the capacity or the throughput of permeate. However, no conversion of units was present in the description as filed.

3.4. The factor used for the conversion from gallons to litres in Claims 1 and 7 as filed amounts in four of the five cases to 4,4 litres per gallon, whilst in one case the factor amounts to 4,412 (17 gal = about 75 litres). The term "about" appears to take the deviation into account, however.

In this respect, it is noted that since the SI units were put in brackets in Claims 1 and 7 as filed, it was immediately evident that the SI units were the converted units, whilst the units "gal" and "gpm" were the original ones, i.e. those of primary relevance.

3.5. The skilled person knows that the unit of volume "gallon" is ambiguous and needs additional information to establish what volume is meant, i.e. to how many litres it corresponds. That unit of volume has got three different meanings in the submissions of the contending parties, as follows:

Canadian or Imperial gallon = 4.546 litres;

US dry gallon = 4.405 litres;

US liquid gallon = 3.785 litres.

The conversion factors submitted by the parties are in line with those indicated in the Perry's Chemical Engineers' Handbook, sixth edition, 1984, Table 1 to 5, a qualified source of common general knowledge in the field.

3.6. The skilled person reading the application as filed using common general knowledge, objectively recognises that the factor used for the conversion from gallons to litres in Claims 1 and 7 as filed exactly corresponds to that for the conversion from the "US dry gallon" to "litres". The unit of volume "US dry gallon", which is larger that the unit of volume "US liquid gallon", (point 3.5, supra), is, however, not a usual unit to indicate a liquid volume. Indeed, it is used to measure dry goods, dry volumes.

Moreover, the application as filed concerns a unit for the purification of water by reverse osmosis. Hence, the application as filed deals with the production of a volume of purified water.

Consequently, since the unit of volume "US dry gallon" is unusual in the field of liquid transport and filtration, its presence implies that an error was present, or, at least, awakes the curiosity, thus the inquisitiveness of the skilled person.

3.7. Throughout the application as filed, the units of volume and throughput "gallon" and "gpm", respectively, are mentioned and referred to several times to indicate capacities and throughputs.

These references concern not only the throughputs of permeate from the reverse osmosis membrane and the capacity of the tanks of the claimed water purification unit but also the rates of commercially available pumps and the throughputs of existing water purification units. In particular, the units "gallon" and "gpm" are mentioned in the description as filed in the following contexts:

(a) The acknowledgement of the relevant prior art includes the mention of a US document that concerns a similar unit for reverse osmosis. The throughput of that unit is also expressed by the units "gallon" and "gpm" (application as published, column 3, lines 21 to 50).

No indication is given that the units in the context of the prior art were distinct from the units in the context of the claimed subject- matter. Nor was any indication given that a conversion from these units to any of the other gallons, e.g. from US liquid gallon to the US dry or the Imperial gallon, were envisaged.

Therefore, the units described in the original US document of the prior art happens to be the same as those used for the claimed subject-matter.

(b) The description of the recommended pumps (FMC triplex plunger pumps) includes the specification of their rates, in "gpm" (application as published, column 13, lines 4 to 12). It has not been contested that these pumps are manufactured by a US Company. US companies in general use the US gallon as a unit of liquid volume for characterising their pumps.

Further, no indication is given in the description as filed that in the context of the mention of the preferred pumps any conversion from the original units had ever been envisaged, i.e. no conversion from a particular gallon to any of the others is apparent.

Therefore, the throughputs of the preferred pumps were expressed in the units of liquid volume supplied by the US manufacturers, without any conversion.

3.8. In conclusion, from the particulars in the description mentioned above, the skilled person using common general knowledge recognises immediately that throughput and capacity of the water purification unit, expressed by the values in "gpm" and "gallons" respectively, can only be understood in terms of units of liquid volume.

Whatever unit of liquid volume is implied from the terms "gallons" and "gpm", the application as filed has not been drawn up in terms of units of dry volumes.

The fact that the conversion factor for the US dry gallon is closer to the conversion factor for the Canadian or Imperial gallon than to that for the US liquid gallon cannot remove the impression that an error was present, because the unusual conversion factor in the claims as filed has no exact correspondence to the Canadian unit either.

From the above it follows that an error was present in the claims as filed, in view of the unusual factor of 4,4 used to convert "US dry gallon" to litres.

3.9. It remains to be decided whether or not it was immediately obvious, from the documents as filed, that nothing else had been intended than what was offered as the proposed correction.

3.9.1. The claimed subject-matter concerns a transportable reverse osmosis unit to produce a volume of purified water to fulfil the need of military personnel in any location in which only contaminated water is present. The maximum dimensions and weight of the unit, as the wide range of conditions under which the unit must operate successfully, inter alia throughput and capacity of the items of the equipment, are specified (patent application as published; column 1, lines 17 to 23; paragraph bridging columns 1 and 2).

3.9.2. The prior art acknowledged in the patent in suit inter alia refers to a particular example of transportable reverse osmosis unit described in an article of the U.S. Army Belvoir Research and Development and Engineering Center. That description also indicates the throughput of permeate and capacity of tanks of the reference prior art units and mentions the units "gpm" and "gals" (column 3, lines 21 to 50).

Since that article originates from a U.S. army center it is immediately evident that the original units mentioned in the prior art document referred to liquid volumes such as US liquid gallon and gpm.

3.9.3. It has not been contested that the pumps recommended in the description as filed, as suitable pass pumps, are manufactured by a U.S. company (application as published, column 13, lines 4 to 12). These pumps are intended for the transport of water through the unit and their throughput rates were given in the unit "gpm". It has not been shown that these commercially available pumps had not been manufactured according to U.S. standards. It has not been shown either that the U.S. manufacturers would use another unit than the usual US unit of liquid volume for such pumps. In this respect it is noted that the "Imperial gallon" is not a customary unit of liquid volume in the U.S.A., such that an express mention would be necessary to indicate that another unit than the US liquid gallon was intended.

Therefore, the mentioned rates of the preferred pumps in the application as filed are to be understood as the customary US units of liquid volume for pumps, i.e. the US liquid gallon or gpm.

The question whether or not the unit "gpm" only corresponds to US liquid gallon per minute, as submitted by the appellants, can thus be left undecided.

3.9.4. The above conclusion cannot be altered by the counter arguments submitted by the respondents, for the following reasons:

(a) As regards the facts that the proprietors are a Canadian entity and the inventors were residents of Canada, this has to be seen in relation to the fact that the right of priority from a U.S. application has been claimed. An applicant who files an application before the USPTO will draw up the application by taking into consideration the units that are customary before the USPTO and in the territory for which the patent is to be granted. This choice is in line with the military specifications for the units, which standards directed to military personnel normally use US units of measure. The contrary has not been shown in this respect. Consequently, the fact that the priority was filed in the U.S.A. plays a more important role to establish what unit of liquid volume was meant than the residence of the proprietors and the inventors in Canada.

(b) As regards the fact that the factor 4.4 in the claims as filed was closer to the factor of conversion from the Imperial gallon to litres than to that from US liquid gallon to litres, it is noted that none of these conversions provided correctly calculated values. Furthermore, there might well be other reasons why these two factors are so close, e.g. historical reasons.

Summing up, the arguments submitted by the respondents do not take into account the specific contexts of the disclosure to gather what was actually meant by the units of volume as filed. Consequently, none of them proves what the proprietors meant to submit as correct information on the date of filing.

3.10. Therefore, the particulars in the description directly and unambiguously lead the skilled person using common general knowledge to the conclusion that the applicants, on the date of filing, meant the use of the US liquid gallon offered as correction.

3.11. It follows from the above, that the conversion of volumes from gallon to litres, or from gpm to litres/h, in Claim 1, using the definition of the US liquid gallon, complies with the requirements of Rule 88, second sentence, EPC and cannot, consequently, contravene the requirements of Article 123(2) EPC.

Consequently, the main request is admissible.

3.12. Since the main request is admissible, there is no need for the Board to decide on the other requests.

4. The grounds of opposition under Article 100(c) EPC do not prejudice the maintenance of the patent in the amended form of the main request.

5. Since the further grounds of opposition mentioned by the opponents have not yet been considered by the Opposition Division, the Board exercises its power to remit the case for further prosecution with respect to the outstanding formal and substantive issues, to give the parties the opportunity to defend their case before two instances (Article 111 EPC).