The patent relates to a mechanically lined pipe (MLP), particularly but not exclusively to provide a submarine pipeline without a risk of buckling/wrinkling.
Brief outline of the case
The patent was revoked and the proprietor appealed.
The board confirmed the revocation.
The case is interesting in that it turns around amendments to Fig 4 as filed and Fig 4 as granted.
The proprietor’s point of view on the patent as granted
The amendments in Figure 4 of the patent as granted represented an obvious correction of an obvious error in Fig 4 of the application as filed on which the contested patent was based.
This correction met the requirements of R 139. It was obvious that an error within the meaning of R 139 was present in the way lengths L1 and L2 were depicted in Figure 4 of the application as filed.
The correction of that error was obvious. The person skilled in the art reading specific passages of the description as filed, especially page 11, lines 5 to 28 of the application as filed, would have immediately understood that Figure 4 as filed was not correct since Figure 4 as filed was not consistent with page 11, lines 5 to 13 of the application as filed.
The representation of L1 and L2 in Figure 4 as filed contradicted other parts of the application as filed.
The representation of L1 and L2 in Figure 4 as filed was inconsistent with the skilled person’s common general knowledge on clad overlay welding of mechanically lined pipes (MLPs), demonstrated, for example, by documents D2, D3, D4, D5 and D16.
It was technically not feasible for a clad overlay weld to extend past an end of a pipe joint and certainly not across a girth weld.
The subject-matter of the patent as granted did not extend beyond the content of the application as filed. The patent as granted narrowed the subject-matter disclosed in the application as filed. Figure 4 of the patent as granted limited the subject-matter to one of the interpretations possible in the application as filed.
The opponent’s point of view on the patent as granted
Figure 4 of the patent as granted was not clearly and unambiguously disclosed in the application as filed. Figure 4 of the application as filed disclosed what the length was.
Changing this length in Figure 4 of the patent as granted resulted in added subject-matter under Art 123(2). There was no basis in the application as filed for changing the measurement of L2 to what was shown in Figure 4 of the patent as granted.
In view of this figure, the skilled person would take a different interpretation from that of the application as filed.
The board’s decision on the patent as granted
This passage in the description defines L2 as “the length of the overlay welds”. This definition is ambiguous as it establishes a relationship between a (single) length and (plural) welds.
This passage could be understood, when read in isolation, as defining that L2 is the length of a single overlay weld or the total length of the welds. When reading page 11, last paragraph in isolation, both interpretations are possible.
This passage does not exclude the possibility that an overlay weld having a length L2 is composed of multiple segments welded together. Moreover, even if interpreted as the length of a single overlay weld, it cannot be determined from the cited passage whether the overlay weld extends only on one side or both sides of the girth weld.
For the proprietor, L2 referred to the length of a single weld extending on one side of the girth weld only.
The board agreed that this may be one of several ways the cited passage of the description as filed can be understood from a linguistic viewpoint. However, while on page 11, line 7 the expression “length of clad overlay weld” (i.e. both “length” and “weld” in singular) is used, this does not necessarily imply that the expression “length of the overlay welds” used on page 11, last paragraph must be understood as referring to the length of a single overlay weld. Moreover, such an interpretation contradicts the depiction of L2 in Figure 4 as filed, where L2 extends on both sides of the girth weld.
For the board, claim 1 as filed was not directed to a pipe joint but to an MLP formed by a plurality of pipe joints. Such an MLP is shown in Figure 4 as filed. The skilled person would understand that Figure 4 as filed shows an MLP in which the ends of each pipe joint (A, B, C) terminate with overlay welds.
Such an interpretation is consistent with claim 1 as filed and is possible regardless of whether the overlay weld terminates at the end of the pipe joint or whether the same overlay weld extends across the girth weld to the adjacent pipe joint. In claim 1 as filed, it is possible that the length refers to the total length of the overlay welds at the ends of two neighbouring pipe joints.
It is not unambiguous that the arrangement of the clad overlay welds in the context of page 11, last paragraph of the application as filed corresponds to that of a conventional MLP. A reference to conventional pipes is made on page 11, second paragraph as filed. Figure 4 as filed, however, does not disclose such a conventional pipe.
The application as filed did not include any reference to document D2, D3, D4, D5 or D16. It is not disclosed that the overlay welds described on page 11, last paragraph of the application as filed are produced in the same way as in any of these documents.
The proprietor’s allegation that clad overlay welds could only extend to and must terminate at the end of the pipe joint is not correct. Whether, during the production of the pipe, there is an intermediate state in which the overlay clad weld terminates at the end of the pipe joint (as shown, for example, in Figure 2 of document D5) is not relevant to the question in hand for claim 1 as granted.
For the board, there is no obvious error within the meaning of R 139 in how lengths L1 and L2 are depicted in Figure 4 of the application as filed on which the contested patent is based. For this reason alone, the amendments in Figure 4 of the patent as granted do not meet the requirements for a correction under R 139.
The ground of opposition under Art 100(c) therefore prejudices the maintenance of the patent as granted.
AR1**
In the case in hand, claim 1 of AR 1** is identical to claim 1 as granted. In view of the case law cited relating to the application of Art 69, the description and drawings are used to determine both the extent of the protection conferred by the patent as granted and the extent of the protection conferred by the patent as amended according to AR1**.
Using Figure 4 of the patent as granted to determine the extent of protection, an arrangement with a total length of the overlay welds of 160 mm, i.e. 80 mm on either side of the girth weld, is not within the extent of the protection conferred by the patent as granted.
However, the same arrangement lies within the extent of the protection conferred by the patent as amended according to the proprietor’s AR1**, which is determined using Figure 4 of the proprietor’s AR1** which corresponds to Fig 4 as filed.
In view of its amended Figure 4, the protection conferred by the patent as amended according to the proprietor’s AR1**, has been extended compared to the protection conferred by the patent as granted.
The board concluded that an amendment to a figure of the patent as granted may extend the protection conferred by the patent even if the claims and the description remain unamended.
Comments
Ambiguous features and added matter
The board considered the definition of L2 as “the length of the overlay welds” as being ambiguous.
In T 1791/16 it was held that, if a claim is ambiguous/unclear, all technically reasonable claim interpretations must be considered. If one of those interpretations contains matter that extends beyond the content of the application as originally filed, it must be concluded that added subject-matter is present.
Reverting to an originally filed feature
Re introducing Fig. 4 as filed induced an extension of protection under Art 123(2).
It is not frequent that an amendment to the description/drawings leads to an infringement of Art 123(2).
It should however be kept in mind that even abiding by Art 123(2), can lead to an infringement of Art 123(2).
Example:
Disclosed range 1-10-15; granted range 10-15. Amending back to the range 1-15 implies an extension of protection.
On the procedure
The correction under R 139 accepted by the ED should not have been carried out as it ended with the patent as granted being infringing Art 123(2).
https://www.epo.org/en/boards-of-appeal/decisions/t220953eu1
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