delivered the opinion of the court:
This is an appeal in an interference proceeding from the decision of the Board of Appeals affirming the decision of the examiner of interferences awarding priority of invention to appellee, Harald Syvertsen.
The invention relates to an improvement in hydraulic turbines “ of the type wherein water is delivered to the runner past an annular series of guide vanes * * * simultaneously adjustable about, parallel axes * * * adapted to direct the water tangentially toward the runner blades.” It involves the idea of arranging stop-pins so that they project into cored-out or open spaces in the guide-vanes, in such' position as to permit free motion of the guide vanes-during normal operation, and, in the event of accidental breakage of the connection between the guide vanes and the shifting ring— *898the means connecting 'the guide vanes to the operating mechanism— prevent them moving beyond a predetermined position and striking the vanes of the runner.
We quote counts 1 and 2 of the five counts involved in the issue:
Count 1. The combination with a turbine and runner, of gate means mounted to have pivotal swinging operation and provided with an open space therein with opposite wall portions, and stop means secured to a part of the turbine and projecting into the open space of the gate means and concealed within the latter and operative with relation to said wall portions to limit the movement of the gate means in the event of breakage of the operating devices therefor.
Count 2. The combination with a ^turbine installation including a runner and pivoted gates having an end portion with walls of stop pin means extending into the gates between the said walls without interfering with the normal opening and closing movements of the latter but preventing abnormal free movement thereof relatively to the runner.
Appellee, Syvertsen, the senior party, filed his application on February 20, 1925, and a patent, No. 1570536, was issued to him on January 19, 1926.
, Appellant, White, the junior party, filed his application on May 27, 1926, more than four months after a patent had been issued to appellee. Accordingly, appellant had the burden of establishing priority of invention beyond a reasonable doubt.
Considerable testimony was introduced by the parties.
The tribunals below, in exhaustive opinions, in which the testimony is carefully analyzed and considered, concurred in holding that appellee conceived and disclosed the invention in 1919; that appellant conceived and disclosed the invention in September, 1924; that the evidence submitted bjr appellant was not sufficient to establish reduction to practice prior to appellee’s filing date; and that, as appellee was the first to conceive and reduce the invention to practice, he was entitled to an award of priority.
With reference to appellant’s claim that he reduced the invention .to practice, prior to appellee’s filing date, the examiner of interferences said:
During the latter part of 1924 two large units for tile Copco Plant of the California-Oregon Power Co. were built in the Allis-Chalmers plant, which units were assembled and inspected for shipment as early as the early part of February.
During the process of construction of these gates the turbine units were subjected to the certain shop tests consisting of manually swinging the gates from open to closed position very violently. This swinging was done beyond the normal open and closed position in order that the pins could be brought into action. There were no other tests of the invention within the knowledge «f Gross, who testified to the above-mentioned tests.
There appears to be considerable diversity of' opinion between the parties in interference as to the effectiveness of these shop tests, it being the view *899of Wliite that such tests constitute a reduction to practice of the invention, while such a contention is opposed by Syvertsen, on the ground that such a test is not an ai>proximation to the action of the forces operating against these gates under normal working conditions.
It will be noted at this point that after the Copco units were installed no difficulties were experienced from the same. Whether this satisfactory operation on the part of the turbine shipped by the AUis-Chalmers Co. was due to the fact that the gates had never been moved to a position where the stops came into play or not is not clear.
It is believed by this tribunal that such shop tests do not constitute a reduction to practice of the invention. While the invention on its face may be considered simple in structure, the action of these gates when under the extreme hydraulic pressures and currents to which they are subjected is rather complex, and to violently swing the gates against the pins does not appeal sufficient approximation to the normal working conditions to which these gates would'be subjected as to constitute a reduction to practice. Theoretically calculating the water pressures and using a safety factor upon which factor the size of the stop is based can not be considered a reduction to practice.
However, the examiner of interferences did not base his decision entirely upon his holding that appellant had failed to reduce the invention to practice until after appellee’s filing date. But, assuming, as he did for the purposes of his decision, that appellant had successfully reduced the invention to practice, he held, after stating and analyzing the testimony pertaining thereto, that appellee was diligent from the time appellant entered the field — September, 1924 — until he reduced the invention to practice by filing his application on February 20,1925.
The Board of Appeals rested its decision squarely upon the proposition that appellant’s shop tests were not sufficient to demonstrate that the invention would function properly in actual use, and that he had not reduced the invention to practice prior to appellee’s filing date.
Counsel for appellant contends that the invention had been completed by an actual reduction to practice for the following reasons: First, the invention in issue was actually constructed and made a part of a hydraulic turbine, the stop pins being so arranged as to permit free motion of the guide vanes during normal operation; second, the stop pins, it is claimed, were designed by competent hydraulic engineers to withstand the strain of the forces produced by the great pressure and velocity of the water rushing past the guide vanes in actual use, although these forces could not be calculated with assured accuracy; third, the stop pins were tested in the shop by swinging the guide vanes violently against them.
It is conceded that the invention was not tested in actual operation of the turbines. In this connection, appellant testified as follows:
*900X Q.- The stop pins, to be practically operative and useful for their intended purpose, would therefore need sufficient strength in the pins themselves and also in the securing of these pins in their sockets, would they not?
A. Yes .
*******
X Q. Your position, as I understand it, is that the ability of the stop pins to withstand the stresses which would be imposed upon them in case of breakage of the controlling connections of the respective vanes during actual running of the turbine could be determined with certainty by calculation. Do I correctly understand your position?
A. The stresses can not he determined) accurately because the force is not definitely Imiown. It was a feature of the design of the stop pins that they should stop the vanes under all emergencies, conditions, such as we assume, but undoubtedly a condition could arise under which the guide vanes might be broken just as the condition could arise by which the casing of the turbine would be exploded or the shaft of the turbine twisted in two. The pins were designed and will be found of sufficient size for limiting the motion of the guide vanes under the worst assumed conditions with which we were familiar. (Italics ours.)
Appellant’s views regarding the necessity of tests to reduce the invention to practice are concisely stated in his testimony. We quote:
⅝ * ⅜ jyr0 • invention is simple and covers a stop or limit device for the motion of the guide vane and when the stop has been installed and the .guide vane once adjusted to it, the device is complete and the invention an accomplished fact.
The witness, Emil Gross, was the only one who testified that the stop pins were tested by having the guide vanes swung violently against them.
In view of the fact that the tribunals below have stated the evidence in considerable detail and have analyzed it in their opinions, we deem it unnecessary to extend this opinion by an exhaustive discussion of-the testimony. We think it is evident that a mere swinging of the guide vanes against the stop pins by two men, violently or otherwise, would prove nothing more than that the stop pins were in proper position. Such a test would certainly not be of great importance, if its purpose was to determine whether the stop pins were of sufficient strength to withstand the incalculable forces to which they would be subjected in actual operation. Accordingly, one of the questions presented is whether or not the actual construction of the involved invention as a part of an hydraulic turbine is sufficient, as stated by appellant in' his testimony, to establish reduction to practice.
Surely, in order to reduce the invention to practice, more would be required than the mere placing of the stop pins in proper position so that they would not interfere with the free motion of the guide vanes during normal operation. The precise purpose of the *901invention was not merely to permit free motion of the guide vanes during normal operation, but to prevent them, in the event of accidental breakage of their connections with the shifting ring, moving beyond a predetermined position and striking the vanes of the runner. Obviously the desired results would not be obtained unless the stop pins were of sufficient strength to accomplish their intended purpose.
It is conceded by appellant that the stresses or forces to which the pins might be subjected in actual operation could not be accurately calculated. There is some evidence to the effect that such forces could be determined with some reasonable degree of accuracy. However, the evidence submitted by appellant to establish that such forces were so ascertained and that the pins were designed to withstand them is not very satisfactory.
The witness, Gross, testifying for appellant, said that, while he could not be positive, he thought the pins were installed in a turbine in the early part of December, 1924.
Appellant’s witness, Henry Walters, stated that he was an inspector in the hydraulic department of the Allis-Chalmers Manufacturing Co., appellant’s assignee; that the stoq) pins were not installed in a hydraulic turbine prior to January, 1925; and that the records of his company indicated that the stop pins were installed in hydraulic turbines sometime later than January 3, 1925, and prior to February 10, 1925.
We think that it has been clearly established by appellee that he conceived the invention early in 1919; that he, and some of his associates in the employ of the S. Morgan Smith Co., had discussed the question of the installation of the invention in hydraulic turbines from time to time, especially on July 29, and August 28, 1924, and thereafter; that, due to the fact that the vanes in turbines theretofore constructed by appellee’s company were too narrow, or otherwise unsuitable to be used with inside stop pins, it was impossible, on August 28, 1924, for appellee to make practical use of the •invention; that, on August 28, 1924, it was understood by appellee and the witness, Jessop, chief engineer of appellee’s assignee, that the invention would be utilized as soon as an order was received for the construction of a turbine; that, early in October, 1924, an order for a turbine was received and immediately thereafter and until January, 1925, the use of the invention as a part of the turbine to be constructed, was many times considered and discussed by appellee and others in the employ of the S. Morgan Smith Co.; that drawings for the vanes of this turbine were prepared in October, 1924, pencil drawings of the invention being added thereto shortly thereafter and prior to November 26, 1924; and that the invention was actually installed in this turbine early in the year 1925.
*902It appears from the record that as early as November, 1924, appel-lee was making preparation for the filing of an application for a patent; and that, in December, 1924, the matter was in the hands of his patent attorney.
In view of the activities of appellee during July, the latter part of August, October, November, and December, 1924, and January and February, 1925, prior to the filing of his application, it is evident that he was not lacking in diligence. The installation of the invention in hydraulic turbines was a matter of importance and required considerable time for discussion and consideration by those charged with the responsibility. That appellant, White, recognized the truth of this assertion, clearly appears from his testimony, in which he stated that even the preparation of preliminary drawings might be subjected to considerable delay. In this connection, he said:
The actual work of putting the change on the drawing would, of course, not require very much time, but the discussion leading up to the actual change might take some little time. In other words, I would not go to the draftsman and say “ Put this in here at once.” I would tell my engineer in charge of design or the chief draftsman to make a preliminary drawing of such change for examination and discussion. A considerable time might well elapse between the request to make the change and the making of the actual change. Again, the conditions of the work in the shop might be such as to not require this change at once and press of other work frequently operates to delay such things. I am not prepared to say how long it would take or did take to make the change from the time it was suggested until the date was placed on the drawing.
Accordingly, we are of opinion that appellee was diligent from the time appellant entered the field — September 10, 1924 — until ap-pellee filed his application — February 20, 1925. Assuming, therefore but not deciding, that appellant reduced the invention to practice shortly before appellee filed his application, nevertheless, appellee was the first to conceive the invention, and, as he was not lacking in diligence, the tribunals below were right in holding that he was entitled to an award of priority.
The decision of the Board of Appeals is affirmed.