Nathan Clifford

“ Examined in the light of these suggestions, it is plain that the steam-valve used by the respondents cannot be held to be an infringement of that described in the specification of either of the three patents representing the invention claimed by the complainant.
Coming to the specification that describes the steam-valve used by the respondents, it will at once be seen that its construction and mode of operation is substantially different in important particulars, as follows: When the valve opens, the steam expands and flows into the annular space around the ground joint. ”

“ When the steam begins to escape from between the surfaces of the valve, it gets between the concave and convex surfaces of the two flanges, and thus acts upon a larger area, and reacts upon the concave surface of the valve, and causes it to open to a greater extent than the ordinary safety-valve. Such a valve, the patentee states, will lift promptly when the required pressure is obtained, and will open to a much greater extent than the valve in common use prior to that invention. ”

“ Taken as a whole, the facts show conclusively that the assignor of the complainant was not the first person to devise means for using the recoil action of steam to assist in lifting the seat of the steam-valve for the purpose described, and it follows that the patent in suit must be limited to what he actually invented, which is the devices, shown in the specification and drawings, to enable the party to avail himself of such recoil action. ”