Monday 12 October 2015

Blocked passages are no passages – OLG Düsseldorf 15 U 139/14

The OLG Düsseldorf had to deal with a motion for preliminary injunction based on a patent relating to a boiler with a combustion chamber provided with a flame defection component deflecting the flame into a space between a flame tube and a heat exchanger. A combustion chamber is surrounded by an exhaust gas chamber and separated therefrom by a heat exchanger surface provided with passages.

According to claim 1 of the patent in suit, these passages for hot combustion gases are provided over the entire length of the combustion chamber.

The defendant had been sentenced for an infringement in earlier proceedings and then came up with a modified version of the boiler were some of the passages in the metallic heat exchanger body were closed with some sort of plastic matter. As a result, only 85 % of the lengths of the combustion chamber were provided with (open) passages and the rest was clogged.

The plaintiff argued that the passages would still exist despite of being clogged by plastics and that the plastics would degraded and burned after a while such that the passages would be open. Export evidence on the last point was contradictory such that the court concluded that the allegedly infringing product as it was presented did not show passages provided over the entire length of the combustion chamber. Once the passages are clogged, they do no longer qualify as passages in the sense of the patent.

Turning to infringement by equivalent means, the board re-emphasizes that the finding of equivalence requires that the considerations of the skilled person are oriented on the technical teaching of the claim and that the claim is not only the starting point but rather the essential basis for the consideration of the person skilled in the art (BGH Pumpeneinrichtung). At the same time, the patentee is limited to the technical teaching he has requested to be protected (BGH Kunststoffurteil). According to the court, the technical teaching given by the patent has to be accepted by the person skilled in the art as sensible and must not be questioned in its technical justification when searching for an equivalent means as a replacement of a feature in the claim.

In the case at issue, the claim teaches that the cylindrical surface of the heat exchanger provided for exchanging heat can be and should be used in its entirety. Accordingly, the required uniform heat transmission onto the heat exchanger can be achieved only when the passages are provided over the entire length of the surface of the heat exchanger which separates the combustion chamber from the exhaust gas chamber.

Consequently, the allegedly infringing embodiment was found not to infringe the patent by equivalent means.
The German Text of the Judgement can be found here.


MaxDrei said...

Haven't read the full Decision yet, but what caught my eye in the above were these words:

"....the plastics would degraded and burned after a while such that the passages would be open. Export evidence on the last point was contradictory such that the court concluded that....."

Do I see it right, that if a fact pleaded by the patent owner is inconvenient, you the infringer promptly procure from an eminent independent university professor a learned expert opinion that professes exactly the opposite, whereupon the court is stopped from finding the pleaded fact to be a fact because there is no facility for detailed cross-examination of the rival technical experts? On infringement, patent owner has the burden of proof, so patent owner loses?

Is this another case like Grimme, where the machine is delivered in a non-infringing format but as the purchaser starts to use the machine its format changes into an infringing format.

If so, the infringer got away with it didn't he? Copies the device including the entire length passages but then plugs them with a plastic plug that burns away soon after you start using the device. Naughty but neat.

We have recently heard a lot about "defeat software". Michael, what was the purpose of the plastic plugs, other than to defeat the patent? Is this case an endorsement, and a demonstration of the efficacy of, defeat devices?

Michael Thesen said...


Good point. This is a preliminary ruling and the taking of evidence is more superficial than in the full procedure on the merits. The patentee (or his expert) has simply alleged that the plastic would burn away but did not produce any convincing experimental evidence on that (the limited time in the preliminary procedure did not allow him to do so). This was clearly not sufficient to establish the high probability of infringement needed fro a preliminary injunction

If experts contradict in the procedure on the merits, the court may (and often does) appoint an independent expert to establish the facts. The experts are interrogated (you might say "cross-examined") and may be in the oral hearing in the procedure on the merits, but usually not in the preliminary procedure.

I do not know if this is a "defeat device" and the parties do not agree in this point either. The judgement says that the plastic plugs have been advertised as a technical progress..

MaxDrei said...

Michael, I kept no copy of what I wrote yesterday (and thought I had posted to you). Never mind. Overnight I have had another thought.

In England, one would not dream of attempting to get interlocutory relief without solid evidence that the accused embodiment is an infringing embodiment. I read that the accused infringer was already putting it about that his plastic plug was there for some special technical purpose (other than to defeat the claim). So the patent owner was on notice, that the plastic plug would frustrate his accusations of infringement.

In not providing solid proof that the plug would not last long, but only an opinion of a person he paid to render an opinion on the matter, what was he hoping the court would do? How could he fail to realise, that this was not going to be enough to get his interim injunction?

Generally, to see off any request for interim relief in Germany, is it sufficient to pay somebody to write an opinion that asserts the opposite of what the patent owner's expert is opining? As far as I know, the writers of the expert opinions never get cross-examined in the English way, and never see their evidence quoted and then forensically dissected in the written decision of the court, so they have no conception of the consequences of being in their expert opinios, shall we say, economical with the truth. Do these opinions even include an English-style "certificate of truth" I wonder.