Vinson, Black, Reed, Frankfurter, Douglas, Murphy, Jackson, Rutledge, Burton
MR. JUSTICE BLACK delivered the opinion of the Court.
Cranford P. Walker, owner of Patent No. 2,156,519, and the other respondents, licensees under the patent, brought this suit in a Federal District Court alleging that petitioner, Halliburton Oil Well Cementing Company, had infringed certain of the claims of the Walker patent. The District Court held the claims in issue valid and infringed by Halliburton. The Circuit Court of Appeals affirmed, 146 F.2d 817, and denied Halliburton's petition for rehearing. 149 F.2d 896. Petitioner's application to this Court for certiorari urged, among other grounds, that the claims held valid failed to make the "full, clear, concise, and exact" description of the alleged invention required by Rev. Stat. 4888, 35 U. S. C. § 33,*fn1 as that statute was
interpreted by us in General Electric Co. v. Wabash Appliance Corp., 304 U.S. 364.*fn2 This statutory requirement of distinctness and certainty in claims is important in patent law. We granted certiorari to consider whether it was correctly applied in this case. 326 U.S. 705.*fn3
The patent in suit was sustained as embodying an improvement over a past patent of Lehr and Wyatt (No. 2,047,974) upon an apparatus designed to facilitate the pumping of oil out of wells which do not have sufficient natural pressures to force the oil to gush. An outline of the background and setting of these patents is helpful to an understanding of the problem presented.
In order to operate a pump in an oil well most efficiently, cheaply, and with the least waste, the pump must be placed in an appropriate relationship to the fluid surface of the oil. Properly to place the pump in this relationship requires knowledge of the distance from the well top to the fluid surface. At least by the latter 1920's problems
of waste and expense in connection with non-gusher oil wells pressed upon the industry. See Railroad Comm'n of Texas v. Rowan & Nichols Oil Co., 310 U.S. 573; Burford v. Sun Oil Co., 319 U.S. 315. It became apparent that inefficient pumping, one cause of waste, was in some measure attributable to lack of accurate knowledge of distance from well top to fluid surface. Ability to measure this distance in each separate non-gusher oil well became an obvious next step in the solution of this minor aspect of the problem of waste.
The surface and internal machinery and the corkscrew conformation of some oil wells make it impractical to measure depth by the familiar method of lowering a rope or cable. In casting about for an alternative method it was quite natural to hit upon the possibility of utilizing a sound-echo-time method. Unknown distances had frequently been ascertained by this method. Given the time elapsing between the injection of a sound into an oil well and the return of its echo from the fluid surface, and assuming the velocity of the sound to be about 1100 feet per second, as it is in the open air, it would be easy to find the distance. Not only had this sound-echo-time method been long known and generally used to find unknown distances, but in 1898 Batcheller, in Patent No. 602,422, had described an apparatus to find a distance in a tubular space. Obviously an oil well is such a space. He described a device whereby the noise from a gun might be injected into a tube; the returning echoes from obstructions agitated a diaphragm, which in turn moved a stylus. The stylus recorded on a piece of paper a graph or diagram showing the variant movements of the diaphragm caused by its response to all the different echo waves.
In the late 1920's the oil industry began to experiment in the use of this same sound-echo-time method for measuring
the distance to the fluid surface in deep oil wells. A product of this experimentation was the Lehr and Wyatt patent, upon which the present patent claims to be an improvement. It proposed to measure the distance by measuring the time of travel of the echo of an "impulse wave" generated by a "sudden change in pressure." The apparatus described included a gas cylinder with a quick operating valve by means of which a short blast of gas could be injected into a well. It was stated in the patent that the time elapsing between the release of the gas and the return of the echo of the waves produced by it could be observed in any desired manner. But the patentee's application and drawings noted that the wave impulses could be recorded by use of a microphone which might include an amplifier and an appropriate device to record a picture of the wave impulses.
This Lehr and Wyatt patent, it is therefore apparent, simply provided an apparatus composed of old and well-known devices to measure the time required for pressure waves to move to and back from the fluid surface of an oil well. But the assumption that sound and pressure waves would travel in oil wells at open-air velocity of 1100 feet per second proved to be erroneous. For this reason the time-velocity ...