delivered the opinion of the court:
This is an appeal from a decision of the Board of Appeals of the United States Patent Office, affirming a decision of the examiner, denying patentability, in view of prior art, of five claims (Nos. 2, 10, 15, 16, and 17) of an application for patent entitled “Improvements in Smokeless Orchard Heaters.” Eight claims stand allowed and are not here involved.
Claim No. 2 seems to be typical:
2. In a heater of the class described a bowl provided with a vapor outlet, a stack mounted on the bowl over the outlet, said stack being enlarged at its lower portion and iirovided at the lower side thereof with upwardly directed *1004openings and having an upwardly converging cono shaped portion extending upwardly from said enlarged portion and provided with louvers.
The references cited are:
Scheu, 1148803, Aug. 3, 1915,
Adams, 1222346, Apr. 10, 1917,
Phillips, 1701727, Feb. 12, 1929.
Appellant’s device comprises a bowl in which oil is burned producing vapor, the bowl provided with an outlet through which the vapor flame passes upwardly into a stack, the stack being sup-, ported by a flange which surrounds the outlet extending upward from the bowl. The stack includes a member referred to as an annular joint which engages the flange; another member designated as an apron, extending outwardly and upwardly from the joint, supplied with openings for the admission of air, a frusto-conical member having openings in its sides in the form of louvers, and a straight stack portion extending upwardly from the cone-shaped portion. The louvers are formed by pressing portions of the side wall of the cone outwardly and air enters, at their lower ends.
The feature most strongly emphasized by appellant is that by means of the louvers, as arranged in the combination described, there is a constant admission of air in the side wall which tends to keep the flame of the burning vapor in the center of the cone and thus prevent the burning out of the wall. In other words, the flame is kept surrounded by a stratum of air which is claimed to protect the wall from overheating.
Appellant’s prior patent, cited as a reference, shows a heater having an oil bowl with a straight stack equipped with louvered openings, the stack rising from the cover of the bowl.
The patent to Adams shows an oil burning heater having a stack, a portion of which is conical shaped, with slits, or openings, for the admission of air.
The patent to Phillips is for an orchard heater having a frusto-conical member as a part of its stack with openings in its lower part for the admission of air.
Patient study has been given to appellant’s arguments respecting the appealed claims. That an improvement over the arrangement of parts in the prior art has been worked out by him may be conceded, but we are unable to discern any modification of such parts which seems to us to amount to invention. He has applied the louvered openings of his prior patent to a cone-shaped part which at least two other prior patents disclose. There is a difference in his arrangement of openings in the lower portion of the frusto-conical member whereby air is admitted below the upwardly rising-vapor flame, but the difference is slight, and the claims, which must *1005be taken as tlie measure of the invention, do not define any structure which seems to be new over the prior art, except such as would be obvious to one skilled in the art.
The decision of the Board of Appeals is affirmed.