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September 22, 1936


The opinion of the court was delivered by: KIRKPATRICK

This is a suit in equity for infringement of United States patent, No. 1,550,332, to Bancel, relating to an improvement in the construction of surface condensers. Claims 1, 2, and 3 of the patent are in suit.

In condensers of the kind with which the patent is concerned, the steam from the exhaust of the prime mover (which in modern practice is usually a steam turbine) is discharged into a closed, cylindrical vessel or shell, the greater part of which is occupied by a bank of tubes extending longitudinally across it, through which cool water flows from one side to the other. As the steam comes into contact with the tubes it is condensed, leaving a partial vacuum, and so reducing the back pressure upon the turbine and greatly increasing its efficiency.

 The plaintiff contends that if this surface is made available for condensing, the size and initial cost of the condenser may be reduced and in addition a saving effected in the pumping of water. This seems obvious. Not so obvious, to me at least, is the explanation by the plaintiff's expert as to the way in which utilizing of all the parts of the tube bank for the purpose of condensing steam has some further effect in increasing the turbine's efficiency by creating a higher vacuum. Nor is it to be assumed that the comparatively small part of the tube bank which does not actually condense steam is pure waste. In many condensers it has a definite function in cooling the air after condensation has taken place -- something which must be done either in the condenser or outside it, as will appear later. However, we may take it that the result which the plaintiff's patent is intended to accomplish is sufficiently advantageous to give it commercial utility.

 With this explanation in mind we turn to the claims of the patent. Claim 1 is typical. It is as follows: "A condenser having tubes with different temperatures along their length resulting in unequal capacities for condensing steam in vertical sections along their length, and means for obtaining substantially equal depth of penetration of steam in said sections along the length of the condenser."

 This, as it stands, is simply a claim for a result, in a certain type of condenser, and for means, generally, for accomplishing it. Under well-known rules which forbid the patenting of results and broadly functional claims it is invalid, unless for some reason those rules do not apply. I have carefully considered the argument advanced by the plaintiff to avoid them, but it is not convincing. Briefly the argument is: (1) That Bancel first discovered the fact that a portion of the tube bank at the cold end does not condense steam, and thus disclosed to the world a serious drawback in condensers as they were then constructed. (2) That the claim should be read in connection with the specification, and when so read is limited to certain specific methods of remedying the defect disclosed. (3) That, inasmuch as a true discovery is involved, extremely simple devices which otherwise might not be patentable will be accorded the quality of real invention.

 For the last proposition, the plaintiff relies principally upon the decision of the Circuit Court of Appeals for the Third Circuit in Cunningham Piano Company v. Aeolian Company, 255 F. 897. The ruling of that case is, of course, accepted unreservedly as the law, and it is quite true, as the plaintiff contends, that very slight, simple, and obvious changes in structure often take on the quality of invention when they are the result of an important discovery. I shall also accept, provisionally (although it seems very improbable), the plaintiff's first proposition, namely, that until Bancel's disclosure, no mechanical engineer ever knew or suspected that portions of the cold end of a surface condenser were not condensing steam. The difficulty with the plaintiff's argument lies with his second proposition.

 In the first place, the language of the claims themselves is so broad that it precludes resort to the specification. There is a limit beyond which courts will not go in sustaining "means" clauses. It is well defined in Davis Sewing Machine Company v. New Departure Manufacturing Company (C.C.A.) 217 F. 775, 782. In that case the courts sustained a means clause, holding that such a clause may be unobjectionable where it is used "with reference to elements or parts of the combination already well-known and designed only to co-operate with the new element in order to make a completely operative unit." Or, as the court later said, "with reference to the connecting parts which permit the salient novelty of the invention to accomplish its function." In such case the means clause is "only a convenient formala of the broadest equivalency of which the real invention permits."

 What the plaintiff really wants the court to do is to substitute the specification for the claims. This, of course, cannot be done. After all, the claim is the grant, and the only purpose for which the specification may be resorted to is to ascertain what was intended by the claim -- in other words, to construe its language. If, in spite of suggestions of various specific structures, the specification taken as a whole merely confirms the view that the claims mean what they say, namely an attempt to cover a result and all possible means of obtaining it, the patent will still be invalid. Now, a careful reading of specification of the Bancel patent leaves one with an even stronger impression that this was exactly what was intended. The patentee sets out seven concrete exemplifications of his thought. They cover three general methods: (1) Increasing the flow of steam into the cold side by directing a larger volume into that side from the turbine exhaust; (2) decreasing the volume of steam on the hot end by various resistance devices, such as baffles or bunching of tubes; and (3) exhausting the air from the condenser by a more powerful pump on the cold side than on the hot side. In other words, he points out that in order to accomplish his result you can either force more steam into the cold side, or pull more steam through it, or block the flow on the hot side. All of these methods may or may not involve the idea of equalizing the pressure drop in both sections. There was a dispute as to this, but I do not think it makes any difference whether they do or not.It seems clear that in the nature of things that there are no ways of getting an equal flow of steam through all sections of the condenser such as the patent describes, without resorting to one or another of the methods pointed out in the specification. Of course, I mean within the fair limits of equivalency.

 The suggestion that the Frey patent, No. 1,729,309, shows a way of accomplishing the result not specified by the patent is without merit. Frey's method is to introduce the circulating water at both ends of the condenser simultaneously. He disclosed a means of securing utilization of all the surface of a condenser, but not the kind of condenser which Bancel was concerned with. The Bancel patent related only to condensers in which the tubes have unequal capacities for condensing steam in vertical sections along their length. It seems to me that, after reading the specification, there can be no doubt that when Bancel spoke of "vertical sections," he meant vertical sections of the tube bank and not vertical sections of each individual tube. Bancel's claims are for means for accomplishing a certain result in a type of condenser which Frey did not undertake to deal with.

 The conclusion is that the claims in suit are invalid as constituting an attempt to patent a result by claiming all means of accomplishing it, the means being described solely in terms of their function which, in turn, is the result desired.

 In a suit involving the same patent in which the Worthington Pump & Machinery Company was the defendant, decided December 12, 1935, ...

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