delivered the opinion of the Court:
The validity of the claims involved is not challenged, the defense being noninfringement “when these claims are read in accordance with the exact meaning of the lang'uage embodied therein.” Specifically, appellants contend that the words in the claims, “and arranged to drain toward said receptacle,” are words of limitation. This contention is based upon the theory that the, prior art discloses practically all that the Mouat patent shows. This theory we cannot accept. The patent most relied upon is that to Koy, No. 714,942, dated September 5, 1899. That patent appellants’ expert admitted “is one that is obviously intended to be used with a system of heating wherein there is considerable steam pressure.” Koy uses a diaphragm, and his system differs in several material respects from Mouat’s. His damper regulator primarily depends upon the control of the. admission of live steam to his movable receptacle. A different problem confronted him and he solved it in a different way. As to the Shurtleff patent (No. 781,467, dated January 31., 1905), appellants’ expert admits that water is forced directly from the boiler itself into the bulb used by Shurtleff. Without further analysis of the patent of the prior art we conclude that Mouat has accomplished a new result in a new way. He has worked out the idea of maintain*394ing a substantially constant pressure within a boiler through the medium of a water trap in which the water is kept at a constant level through condensation. And Mouat also is the first to employ a movable draft control receptacle which is operated by water forced into it from the water trap by the steam-pipe connection with the steam space of the boiler.
It is evident, therefore, that pipe “11” performs a double function. Primarily, it permits the same pressure to be exerted on the surface of the water in trap “6” as there is upon the surface of the water in the boiler, — and it is through this pressure that the movable damper receptacle is made to operate. Pipe “11” also is made to serve the secondary purpose of keeping trap “6” supplied with water through condensation. Once having conceived the idea that these two purposes might he combined in pipe “11,” it would be a comparatively simple matter so to vary the construction of that pipe as to effect the objects desired. In other words, had it been found that there was not sufficient condensation, pipe “11” could have been made a little larger or the vertical portion a little longer. Appellants’ expert admitted this, saying that should pipe “11” prove inadequate it might be extended “so as to furnish an ample condensing surface.” Moreover, the steam pressure being toward and not away from receptacle “6,” it is apparent that even though the upper portion of pipe “11” should be horizontal the apparatus still would be operative.
But, even disregarding what is common knowledge and indulging in the extremely technical interpretation insisted upon by appellants, pipe “11” still would be “arranged to drain toward said receptacle,” even though its upper section should be horizontal, because a substantial portion of it is vertical and the vertical section is connected with receptacle “6.” We are fully convinced, however, that the words just quoted should be given such an interpretation as will adequately protect this patentee. In using them he merely was describing a particular construction, or, as he says in his specification, “one exemplification.” Having in mind the scope of his invention, the double function of pipe “11,” and the end to he attained, we are *395clearly of opinion that appellants have taken an altogether too technical view of these claims. And there is authority for this view. Winans v. Denmead, 15 How. 330, 14 L. ed. 717: Keystone Bridge Co. v. Phœnix Iron Co. 95 U. S. 274, 24 L. ed. 344; Hoyt v. Horne, 145 U. S. 302, 36 L. ed. 713, 12 Sup. Ct. Rep. 922; Metallic Extraction Co. v. Brown, 43 C. C. A. 568, 104 Fed. 345; Adam v. Folger, 56 C. C. A. 540, 120 Fed. 260; W. W. Sly Mfg. Co. v. Russell & Co. 110 C. C. A. 625, 189 Fed. 61.
Mention is made in appellant’s brief of the file wrapper, but that paper was not made a part of the record by exhibit or otherwise, nor is to be found in the files of the case. However, appellee answering says that claim “7” of the patent in suit originally was claim “12” of the application as filed.
It is of no consetpience that appellants have conducted the returning water from the radiators tlirougTi the water-trap receiver. because they have not eliminated and could not eliminate pipe "11.” In other wmrds, appellants have appropriated the essential elements of the Mouat combination; and it is immaterial, in our view, whether they have added an element not necessary to the operativeness of the combination. Whether much or little water in appellants’ construction drops into receptacle “6” is not important in view of the admitted fact that pipe “11” is indispensable to the success of appellants’ apparatus and is capable of performing- the same functions performed in the Mouat apparatus. There may be a distinction, but there is no essential difference in the two combinations, and to refuse protection to this patentee would be entirely to ignore the purpose of the patent laws.
The decree is affirmed, with costs. Affirmed.