¶1William T. Sevald, Royal Oak, Mich., for appellant.
¶2Clarence W. Moore, Washington, D. C. (Jere W. Sears, Washington, D. C., of -counsel), for Commissioner of Patents.
¶3Before WORLEY, Chief Judge, and RICH, MARTIN, SMITH and ALMOND, Judges.
¶5The question the court must answer in this appeal is whether appellants’ novel air cleaner, as represented by claims 1, 2 and 3 of their application serial No. 816,556 entitled “Air Cleaner” filed on May 28, 1959, is an obvious variation of the devices of the prior art. No claims stand allowed in the application, which is stated to be a continuation-in-part of application serial No. 698,474 filed November 25, 1957 for an “air cleaner device.”
¶6The centrifugal air cleaner appellants disclose is useful on internal combustion engines or air-compressors, particularly under very dusty conditions. The air cleaner is of simple construction and is “self cleaning” in operation. Reference to the accompanying figures of the application will aid in an understanding of the structure and operation of the device:
¶8_ Figure 1 shows the air cleaner consisting of separator portion 10 mounted on the air intake of an internal combustion engine such as that of a tractor, with; a hose 15 connected to a vacuum developing portion or venturi 16 mounted on the *311engine exhaust. Cross section views of those two portions of the device are seen -on the right and left of Figure 2. In operation, when the engine is running, air is drawn into the cleaner via eap 30 following the path indicated by arrows A and B. The air flows over inclined wanes 29 which impart a “spiral swirling motion” to it. As the air is drawn •downward in its spinning path, entrained dirt is centrifugally thrown toward the ■outer wall 20 of the “tank” or can-shaped separator portion of the air cleaner. The dirt and some air enters collecting chamber 17 by passing through the space 26 between the wall 20 and baffle 25, while relatively clean air enters carburetor air intake 12 via tube 11. The air-entrained dirt passes out of chamber 17 into hose 15 as indicated by the arrow we have labeled C. The air and dirt is drawn out by the action of the venturi or vacuum developing device 16. Exhaust gases exit from the engine as shown by the arrow we have labeled E. As the gases pass through the tapered section 44 they draw the dust laden air from hose 15 as shown by the arrow we label D.
¶9There is no question that the cleaner is operable and has achieved some degree of commercial success. However, it is our view that the appellants’ claimed air cleaner1 is an obvious variation of the following references:
¶10Schütz 1,496,908 June 10, 1924
¶11Altgelt 2,033,368 March 10, 1936
¶12Soeiété (French) 1,106,334 Dec. 19, 1955
¶13The Altgelt reference is relied on to show a cap used on the intake of a tractor *312air cleaner. The reference is used only-in conjunction with the rejection of claim 2, the sole claim calling for a cap.
¶14The major reference, Société, describes “fluid separators operating by centrifugal force,” to be used particularly for the separation of moisture from, steam. The detailed description will be-by way of reference to the drawing therein:
¶16The drawing shows a tubular separator section or “connection” 1 which is the same size as the steam line to which it is connected by employing flanges 2 at either end. Helical fins 7 are mounted within the tubular section. Moist gases or steam flow downwardly in the direction of arrow A, while the helical surfaces produce “a rotation of the gas or steam current.” A larger annular casing 3 is spaced around a slot 4 and funnel-shaped surface 5 and together define a collection chamber. Société states:
“ … The liquid droplets contained in the current thus precipitate on the helical surfaces and on the inner wall of the connection, then flow downward over the funnel-shaped surface of the circular slot into the annular casing, from which they may be extracted at any time. … *313■“ … The upper edge of funnel 5 penetrates into connection 1 only to the extent sufficient so that the fluid flowing from the inner wall of the connection and on helical surfaces 7 must be trapped by the funnel and diverted through circular slot 4 into casing 3. … ”
¶17.A valve “or usual condensate extraction device” is provided at outlet 6 to tap off the moisture that has been separated.
¶18Schütz is directed to a “suction air ■cleaner” used for “eliminating dust from the air before it enters the carburetors of internal combustion engines,” and which is “non-clogging in operation.” The suction air cleaner of Schütz clearly is a centrifugal type cleaner, the dust laden air being caused to “whirl with high velocity” by tangential inlet projections or fins and the engine suction. The dust is ejected at the bottom of a downward path by use of a venturi, while the clean air is directed upwardly to the ■engine intake by a conical baffle. As we view the rejection of the examiner and the decision of the board, the Schütz reference was used for two purposes. First, to show the exhaust driven “Venturi tube” or vacuum developing device, and .second, to show the concept of such a venturi device in combination with an air ■cleaner as the means by which dust is ejected.
¶19Claims 1 and 3 were rejected by the examiner as “unpatentable over Société in view of Schütz,” while claim 2 was .so rejected “further in view of Alt-.gelt,” and the board affirmed. Since the differences in the claimed structure and that of the references are readily apparent, we take “unpatentable over” as meaning obvious within the meaning of 35 USC 103.
¶20As will be apparent from their arguments discussed below, appellants seem to misconstrue the rejection. The differences in the separator portion of the structure claimed, as compared to that of Société, were deemed obvious by the examiner and the board, and we agree, while the combination of the separator portion with venturi and cap, and their use on internal combustion engines at normal air pressures are equally obvious to those in the art as shown by Schütz and Altgelt. With regard to the differences, the examiner and board are not combining the references by modifying the structure of Société by reference to structure shown in Altgelt or Schütz. With regard to the combination, it is evident that centrifugal separation operates on the differences in density between the carrier gas and the solid or liquid particles to be separated. The references thus cannot be said to be from non-analogous arts and thereby not combinable. We shall discuss these two aspects of the rejection separately below.
¶21I The Differences
¶22Appellants’ major contention concerning the differences in their structure as compared to Société appears best summarized by the argument that:
“The applicants deny that the Societe patent may be combined with the Schütz patent as alleged by the Patent Office. The applicants contend that the modifications made by the Patent Office are based on the applicants’ invention. Neither the Societe patent nor the Schütz patent singly or in combination suggest their combination nor does either patent suggest taking the Societe patent out of a steam pressure line and connecting two low pressure devices to one end and exposing the other end to atmospheric pressure. These charges [sic: changes?] by the Patent Office are certainly not obvious to one having ordinary skill in the art based on the Societe and Schütz patents. Of course these charges [sic: changes?] are obvious in view of the applicants’ invention. This [,] however, is improper and the applicants therefore object.”
¶23Appellants, in supporting that position, urge certain differences between their device described as a “tank” and the Société device which is termed a “tube.” We take these differences as merely verbal.
¶24*314Appellants also point to various internal structural modifications that must be made in Société in order to overcome the claimed differences. While we have considered all the arguments, we will discuss only the major ones here.
¶25Appellants point to the fact that the claimed collection chamber is radially spaced inside the walls of the main air chamber while that of Société is outside. This difference is not convincing since Société discloses:
“… The diameters of known fluid separators operating by centrifugal force are generally considerably greater than the diameter of the pipe through which gases or vapors actually flow. … ”
¶26Further, appellants have pointed to no results traceable to this feature which would indicate that it is other than an obvious matter of design choice.
¶27Much discussion has been had by appellants and the examiner about the effect of the claim limitation:
“ … the cumulative cross-sectional area between said vanes being slightly more than the cross sectional area of said tube; … ”
¶28After careful analysis and discussion of flow paths, air pressure and velocity, the examiner concluded that this limitation:
“ … is therefore not found to patentably distinguish since even if it is assumed to state dimensional relationship different from Societe, it does not produce any different effect or result. … ”
¶29The gist of appellants’ response is that:
“In fluid systems the relationships of size and the positions of baffles are critical. The Patent Office has not shown that they are not critical.”
¶30We fail to see how such a general allegation in a brief can rebut the relationships between flow paths, air pressure and velocity stated by the examiner to be the same herein as in Société. The examiner analyzed, with inference to the well-known Bernoulli principle,2 the effect structural differences might have on the operation of appellants’ device as compared to that of Société. Appellants do-not challenge the statements as being incorrect, but assert that a reference by the examiner to the Bernoulli principle-alone is not proper here. It was perhaps the best means available to the examiner of explaining the reasons for his conclusion of obviousness, and since unrebutted' by factual evidence of any critical relationship in position or size, or of any difference in effect or result, we think the position of the examiner to be sound. Appellants have failed to show that the-change in the vanes, the use of an inner rather than outer collection chamber and the use of a smaller output tube, for example, as compared to Société, result in a difference in function or give unexpected results. Such changes in design of the various features are no more than obvious variations consistent with the principles known in that art.
¶31II The Combination
¶32We see little merit in the objections to the combination of Altgelt, as showing the cap, and Schütz, as showing the ven-turi tube, with Société. As the board noted:
“ … Inclusion of a cap over the air inlet is urged by the Examiner to be no more than an additive feature of well known structure and purpose in such combinations as taught by Altgelt.”
¶33Although appellants contend the board erred in stating: “Appellants have presented no arguments indicating that these features are of particular significance to the particular separator structure shown,” the present arguments are not well taken in view of appellants’ reply brief before the board which stated: “Admittedly the cap is shown in Altgelt. *315and a suction [a venturi tube] shown in Schütz.” Appellants now urge that:
“ … the cap necessitates that the air travels radially into the top of the tank and prevents air from directly axially entering the top of the tank.
“As to the vacuum inducing device at the dirt outlet, the structure claimed is very efficient and not shown in the prior art.”
¶34That description of what the cap does ■describes precisely what the cap in the air cleaner of Altgelt does. Contrary to appellants’ contention, the vacuum inducing device is shown in the prior art.
¶35We grant that Schütz does use his venturi in an alternative fashion, i. e., the exhaust and dust laden air inputs are reversed. The examiner in his answer pointed this out but stated:
“ … Insofar as the operation of the aspirator is concerned it is immaterial which arrangement is used. All that is required is that the inlet for dirt laden gases be adjacent the throat (low pressure zone) of the venturi.”
¶36We agree, and also note that Schütz teaches his arrangement to be a six to ten-fold improvement over the suction available by the very arrangement which appellants use.
¶37We are satisfied that the cap and ven-turi elements emphasized by appellants are obvious additions which are taught by the Schütz and Altgelt references to be useful as a matter of choice in the combination. No unexpected result stems from their use in the combination; the combination works as expected.
¶38Our view of this controversy is not changed by the many variations in the argument that the structure is novel. In view of the above we affirm the decision of the Board of Appeals.
¶39Affirmed.
¶40SMITH, J., concurs in the result.