T 1413/08 – There Are Alternatives

Claims 1 and 2 on file in this examination appeal case read (in English translation):

1. A replaceable liquid filter, particularly for the lubricating oil of an internal combustion engine, comprising a substantially cup-shaped housing (12) with a concentrically disposed outlet opening (17) for the filtered liquid and at least one inlet opening (16) for liquid to be filtered, and
a filter element (18) disposed in a sealing manner between the inlet opening (16) and the outlet opening (17), wherein the housing (12) is connected to a top plate (14), and the top plate (14) is connected to an end plate (13), characterised in that the top plate (14) encloses a displacement space (24) which is disposed in a feed chamber in a part which mates with the replaceable liquid filter, so that the inlet opening (16) in the top plate (14) is disposed in the area of the displacement space (24), wherein a backflow check valve (26) is disposed in the area of the displacement space (24), such that liquid cannot leak from the replaceable liquid filter (10) when the filter is detached.

2. A replaceable liquid filter, particularly for the lubricating oil of an internal combustion engine, comprising a substantially cup-shaped housing (12) with a concentrically disposed outlet opening (17) for the filtered liquid and at least one inlet opening (16) for liquid to be filtered, and a filter element (18) disposed in a sealing manner between the inlet opening (16) and the outlet opening (17), wherein the housing (12) is connected to a top plate (14), and the top plate (14) is connected to an end plate (13), characterised in that a volume contour (35), preferably made of metal, is connected to the end plate (13) and the top plate (14), which comprises the inlet opening (16) on the one hand and extends into the cylinder head (11) on the other hand, thereby forming a displacement space (24), wherein a backflow check valve (26) is disposed in the area of the displacement space (24), such that liquid cannot leak from the replaceable liquid filter (10) when the filter is detached from the cylinder head (11). (my emphasis)

The Board inter alia had to decide whether it was justified to have two independent product claims.

*** Translation of the German original ***

[4] The Board is of the opinion that the subject-matter of independent product claims 1 and 2 define alternative solutions for the problem defined under point [3.3] [i.e. to provide a replaceable liquid filter where the amount of liquid that is released when the filter is disassembled is reduced]. As in particular the characterising apparatus parts according to these alternative solutions are different and do not correspond to each other, apart from their suitability to solve the problem, the Board can accept that it is inappropriate to cover the alternatives by a single claim. Thus the situation corresponds to one of the exceptions provided in R 43(2)(c) according to which the European patent application may contain more than one independent claim of the same category.

Moreover, the inventions according to claim 1 or 2 have the technical relationship that is required by R 44. It is expressed in the corresponding particular technical features which characterise the subject-matter of claims 1 and 2, respectively and which define a contribution which the respective claimed invention makes over the prior art.

Thus the requirement of unity of invention is fulfilled (A 82).

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