Non-return valve for urinals: Does it stink up to the sky? Or is it gas-tight?

Case No. O2014_002 ¦ Main Hearing of 14 September 2015

The patent in suit is EP 1 579 133 B1; plaintiff and currently registered owner of the patent in Swissreg is Daspaco AG.

Independent claim 1 of EP’133 reads as follows:

A non-return valve (3), comprising an inlet section (5) in the form of a self-supporting trough-shaped section and an outlet section, the outlet section being made of a flexible resilient material connected to the inlet section (5), whereby the outlet section comprises a flat flexible resilient strip (6) with a high inherent degree of flexibility, the strip (6) being connected with the inlet section (5) at its upper edge; and further comprising a component that is separate from the strip (6) providing a complementary surface against which the lower end of the flexible strip (6) may seal.

Defendant (1) is Enswico AG. More precisely, it was. Enswico AG has recently sold its operative business, according to information on their website (screenshot below taken today). Bankruptcy proceedings have been opened with decision of 31 August 2015; see Commercial Register. Thus, proceedings have been split and today’s hearing in the matter O2014_002 only concerned the second defendant, Van Allmen AG. Separate proceedings against Enswico AG (in liquidation) will be continued, too (O2015_013). The attacked product is Enswico’s valve used in waterless urinal systems:

This video (see helps to understand how the valve works:

The second defendant, Von Allmen AG, apparently produced the valves for Enswico AG. Two embodiments of the valve are at stake: A first generation embodiment where the flaps were not connected at the lower end; and a second generation where the two flaps are interconnected by connectors. It has been argued that the second generation embodiment is subject of granted EP 2 553 299 B1 (see characterizing part of claim 1 and Fig. 8 ff).

From what has been argued I conclude that the preliminary assessment of the reporting judge must have been in favour of the plaintiff’s position, i.e. that the patent is infringed (by both embodiments) and valid. Accordingly, the plaintiff’s opening pleadings were succinct, fully supporting the assessment of the reporting judge. Not so the defendant’s reply. In brief, four major issues were adressed in subsequent pleadings of the parties:

i)    (Lack of) distinctiveness of the request

From what has been argued I tend to assume that the claim language “high inherent degree of flexibility” is literally recited in the plaintiff’s request for injunctive relief. Parties dissented on the question of whether or not this wording is specific enough in order to meet the legal requirements as definied e.g. in the decision BGE 131 III 70 E3.3 of the Supreme Court. Defendant insisted that the case should not be considered in view of the improper request.

ii)    Claim construction by the reporting judge

Fig. 3 of D1
Fig. 3 of D1

I understood from the plaintiff’s pleadings that the reporting judge had interpreted a non-return valve according to the patent as a valve which is gas-tight when it is slack, without special outer influences. It was disputed that a gas-tight closure is achieved in the dry state, at least for the second generation embodiment. In a nutshell, defendant argued that if the reporting judge’s assessment were correct, then at least the second generation embodiment cannot infringe since it is not gas-tight without special outer influences. Else, if the construction of this feature was not correct, at least the prior art document D1 (US 3 835 857) would be novelty-destroying for the patent in suit.

Next, the inlet section (5) in the form of a self-supporting trough-shaped section has been discussed. Defendant argued that if in D1 the inlet section was not self-supporting since it is made from the same material as the flaps, then both the first and second generation could not infringe — because the same material is used for both elements.

iii)    Undue extension of subject-matter

Defendant raised various objections in this respect. First, the documents as filed allegedly only disclosed a valve that “has a component (4) having a flat strip (6).” Defendant argued that this implies a one-piece construction, in light of the whole specification (e.g. manufactured in an injection moulding process). To the contrary, claim 1 as recited above requires a connection (of two parts?). Defendant argued that this constitutes an undue extension of subject-matter.

Second, defendant alleged a shift from a complementary component to (only) a complementary surface of such component in the granted claim.

iv)    Equivalency

From the discussion at the hearing, I conclude that two features of the claim were held to be not literally fulfilled by the attacked embodiments, but rather only under the doctrine of equivalents. Interestingly, the features at stake are marked-up as amendments in the DREX, i.e. were at least not irrelevant for the patent to proceed to grant: First, that the component is separate from the strip. Note that the second generation embodiment has connectors (which, in turn, is a patented embodiment; see above). And second, that it is (only?) the lower end of the flexible strip that seals.

Parties finally entered into non-public settlement negotiations.

Reported by Martin WILMING


Case No. O2014_002 ¦ Main Hearing of 14 September 2015

Daspaco AG
(1) Enswico AG
(2) Von Allmen AG

Board of Judges:

  • Dr. Dieter BRÄNDLE
  • Dr. Tobias BREMI
  • Dr. Christoph GASSER
  • Dr. Ralph SCHLOSSER
  • Werner ROSHARDT

Court Clerk


Reporting Judge:

  • Dr. Tobias BREMI

Representative(s) of Plaintiff:

Representative(s) of Defendant (2):

  • Dr. Demian STAUBER (Rentsch)
  • Dr. Alfred KÖPF (Rentsch), assisting in patent matters
  • Dr. Andri HESS (Homburger), “supporting the team”


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