436 F2d 1388 Application of Donald L Sellman

436 F.2d 1388

Application of Donald L. SELLMAN.

Patent Appeal No. 8438.

United States Court of Customs and Patent Appeals.

February 18, 1971.

Rehearing Denied April 22, 1971.

Donald L. Sellman, pro se.

S. Wm. Cochran, Washington, D. C., for the Commissioner of Patents; R. V. Lupo, Washington, D. C., of counsel.

Before RICH, ALMOND, BALDWIN, and LANE, Judges, and FORD, Judge, United States Customs Court, sitting by designation.

RICH, Judge.

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This appeal is from the decision of the Patent Office Board of Appeals affirming the rejection of claims 1-5 in application serial No. 622,304, filed March 10, 1967, for "Fuel Flow Control System." According to the examiner, the application is a continuation-in-part of serial No. 371,494, filed June 1, 1964, now abandoned. We affirm.


The invention relates to fuel systems for gasoline engines and is intended to prevent vapor lock,1 "percolating,"2 and "slugging,"3 particularly in modern engines having downdraft carburetors and diaphragm fuel pumps, said to be subject to the foregoing difficulties when hot. Applicant undertakes to solve these difficulties by providing one or two closed vessels, each having a fuel inlet at the top and a fuel outlet at the bottom, located above the fuel bowl of the carburetor or above the fuel pump or both, so that fuel may move to one or both of these units by gravity from the closed vessel, gas bubbles, if present, accumulating in the top or dome of the chamber.


Applicant's Fig. IV, below, shows diagrammatically what he claims, the carburetor being 4, the fuel pump 6, the closed vessels 1, and the fuel lines 7 and 8. Fuel flow is, of course, through the path 8, 1, 6, 7, 1, 4.




His explanation of the claims is that claims 1 and 2 are complete combination claims and claims 3, 4, and 5 are sub-combination claims, claim 1 being a combination of claims 3 and 4 and claim 2 a combination of claims 3 and 5. Claim 3 recites only the vessel 1 associated with the fuel pump 6 and claim 5 only the vessel 1 associated with the carburetor 4. Claim 4 is like claim 5 but also states that the vessel inlet is connected to the pump outlet.

Claim 1 reads:


1. A fuel flow control system for internal combustion engines having a diaphragm type fuel pump and a downdraft carburetor comprising in combination;


(a) two closed vessels connected in the fuel conduit through which all of the fuel flows;

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(b) one vessel located substantially above the carburetor fuel bowl and whose outlet is in series with the float controlled carburetor fuel bowl inlet valve,


the inlet opening of said vessel connected in series by the fuel conduit to the output of the fuel pump,


said vessel inlet opening being substantially above said outlet opening so that liquid fuel will flow by gravity from the inlet of said vessel through the bottom opening of said vessel into the float controlled valve opening of the carburetor fuel bowl;


(c) and the other vessel located in the fuel conduit in series between the main supply tank and the intake of the fuel pump,


having the outlet of said vessel substantially on the same level as the fuel pump inlet,


said vessel inlet opening being substantially above said vessel outlet opening so that liquid fuel will flow by gravity from the top opening of said vessel through the bottom opening of said vessel into said fuel pump inlet opening.

The references relied on are:


Bright         1,374,983     Apr. 19, 1921
Basle          1,408,163     Feb. 28, 1922
La Bour        1,578,236     Mar. 23, 1926
McInnerney     2,253,717     Aug. 26, 1941
Jordan         2,969,110     Jan. 24, 1961

Claims 1 and 2 stand rejected as unpatentable over McInnerney or Basle in view of La Bour and Jordan, claim 3 as unpatentable over La Bour and Jordan, claim 4 as unpatentable over Basle in view of Bright, and claim 5 as unpatentable over McInnerney or Basle.


The essence of appellant's argument for the patentability of his claimed invention is that he is controlling or preventing percolation in a carburetor by providing gravity flow of fuel from the vessel which he positions above the float chamber of the carburetor; and he is controlling or preventing vapor lock in a diaphragm-type fuel pump by gravity flow of fuel to the pump from the vessel he positions in advance of the pump. He claims these arrangements separately in claims 3, 4, and 5 and he claims them together in claims 1 and 2. But however he claims them, it comes down to the fundamental idea of providing gravity flow of fuel which he seems to feel is a novel suggestion, at least for his purposes.


Basle discloses an auxiliary fuel reservoir with an inlet at the top and an outlet at the bottom into which gasoline is sucked from the main fuel tank of an automobile by a pump. The reservoir is positioned above the carburetor and the fuel flows to the float chamber of the carburetor by gravity. Any flow from the reservoir would tend to create a vacuum and suck fuel from the main tank.


McInnerney, who was concerned with preventing vapor lock, shows a chamber having an outlet from its bottom which connects to the float chamber of a carburetor and an inlet which is well above its bottom connected to the outlet of a diaphragm-type fuel pump, the purpose of the chamber, which is provided with cooling fins, being to condense any vaporized fuel. The liquid fuel is stored in the chamber above the carburetor inlet and flows thereto by gravity. Appellant says this is not so but we consider that he is misinterpreting the patent in this respect.


Appellant refers to certain check valves in McInnerney and Basle but we agree with the Patent Office Solicitor's statement that "the check valves in Basle and McInnerney do not impede the inherent gravity flow of liquid through the respective vessels during their operation."


As for those claims which include or are directed to the feature of placing the gravity-feeding, fuel-supply vessel between the main fuel tank and the fuel pump, Jordan shows such a location of an auxiliary fuel tank, though in the drawing it is below the fuel pump. La Bour is relied on for its showing in a centrifugal liquid pump structure of a holding tank for a supply of liquid maintained above the pump inlet for priming purposes and fed to the pump on start-up by gravity. Jordan, moreover, as the solicitor points out, suggests a wide latitude in the location of his reservoir, saying "this vessel may be located ahead of, in line with, or rearwardly of the fuel pump." We think La Bour would make it obvious to locate it above the pump inlet. Nothing in Jordan suggests it would be undesirable to do so.


The Bright reference calls for no special comment. It shows a complex vacuum-tank type of automobile fuel supply but was cited only for the disclosure of a secondary fuel supply tank mounted above the float chamber of the carburetor for gravity feed thereto.


We have carefully considered appellant's extensive arguments on the facts and the law but, considering the breadth of his claims, the essential simplicity of the concepts relied on for patentability, and the closeness of the teachings of the prior art references with respect to those concepts, we are unable to find error in the conclusion of the Patent Office that the claimed subject matter is obvious within the meaning of 35 U.S.C. § 103.


The decision of the board is affirmed.





Interference with fuel flow due to replacement of liquid fuel with fuel vapor in the system


"Percolating" is said to be boiling or vaporizing of fuel in the carburetor fuel bowl


"Slugging" is pushing slugs of liquid fuel through the carburetor discharge nozzle by large gas bubbles