Application of Sidney Dilnot

300 F.2d 945, 49 C.C.P.A. 1015
CourtCourt of Customs and Patent Appeals
DecidedApril 13, 1962
DocketPatent Appeal 6774
StatusPublished
Cited by11 cases

This text of 300 F.2d 945 (Application of Sidney Dilnot) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of Sidney Dilnot, 300 F.2d 945, 49 C.C.P.A. 1015 (ccpa 1962).

Opinion

MARTIN, Judge.

This is an appeal from a decision of the Board of Appeals of the United States Patent Office regarding appel *946 lant’s application for a patent on “Light Weight Aerated Concrete.” Six claims reciting a method of making this material were allowed by the examiner. The sole issue is the patentability of article claims 10-13 and 20 in view of the Fraser patent, Re. 23,228, issued May 9, 1950.

Claim 10. is representative and reads as follows:

“10. An article of manufacture comprising a form retaining self sustaining body of indurated, dense calcium silicate hydrate matrix, said body having in the dry state an apparent density of about 15 to 40 pounds per cubic foot and comprising substantially from about 16 to about 70 per cent of its volume as small spherical macroscopic voids, and containing from about one-fourth pound to five pounds substantially non-reactive fiber per cubic foot contributing to the transverse strength of the body, the fiber ranging in length between about three-tenths to about two and one-half centimeters, said body having a transverse strength in excess of one hundred pounds per square inch.”

The application, much amended, relates to certain calcium silicate hydrate materials said to be useful as insulating or structural materials. 1

It appears to be well known that calcareous materials such as lime will react with siliceous materials such as silica or sand when mixtures of these are heated in the presence of moisture. For example, common “sand-lime bricks” are made by such a process. Apparently, such bricks have an undesirably high density for some purposes.

Appellant discloses that calcium silicate hydrate materials with desirable physical characteristics, particularly, low density, high transverse strength, and resistance to passage of both heat and water, can be prepared by incorporating 0.25 to 5 pounds of a non-reactive fiber per cubic foot of final dry product plus a quantity of a stable preformed acqueous foam into the usual calcareous-siliceous-aqueous reaction mass, and heating this mixture in molds in the usual manner.

The specification as filed contained the following description of appellant’s claimed article:

“Therefore, the product to which this invention relates is an aerated calcium silicate hydrate product containing a small amount of asbestos and/or cellulose fibers and characterized by a high percentage of non-communicating gas-filled cells, and having an apparent density on a dry basis of between about 15 pounds per cubic foot and about 40 pounds per cubic foot, * * * ”

By an amendment, entered without objection by the examiner, appellant can-celled the above description and substituted for it the following statement:

“The products of this invention are self-sustaining bodies of a dense calcium silicate hydrate matrix having distributed therein macroscopic spherical voids, and fibers at a distribution density of about .25 to 5 pounds per cubic foot of the body, the bodies having an apparent density on a dry basis of between about 15 to 40 pounds per cubic foot.”

It is said by appellant that the added fibers increase the transverse strength of the final product by distributing local stresses and strains over a larger volume of product. The suggested asbestos or cellulose fibers should range in length from 0.3 to 2.5 centimeters and should have a diameter not exceeding one millimeter.

*947 The “non-communicating gas-filled cells” or “macroscopic spherical voids” in the final product account for its relatively low density. Apparently each individual gas bubble in the stable preformed foam becomes a “cell” or “void” in the final product. Suitable foams are prepared by incorporating a gas, usually air, into a dilute aqueous solution of a foaming agent such as a “hydrolyzed protein.”

The Fraser patent discloses production of a strong, form-retaining, moisture-resistant, low-density heat insulating material by heating a mixture of finely divided lime and silica in the presence of a “very large volume of water” and a quantity of “fine spiculated fibers” of asbestos or cellulose. The resulting hydrated calcium silicate is said by Fraser to be “characterized by a loose, open, fibrous structure, in which the fibers are randomly arranged and separated or spaced apart by a system of fine, continuous, capillary air spaces.” Apparently the hydrated calcium silicate is capable of forming needle-like or fibrous crystals, and, in being formed from lime and silica, is encouraged to assume this crystal form by the presence of the spiculated dispersed fibers of asbestos or cellulose which should range in length from 0.001 to 0.2 centimeters and which are said to “present free, freshly fractured surfaces” which are “active as incipient centers for the crystallization of the fibrous crystal-forming reagents,” i. e., lime and silica.

Example II of Fraser appears to be representative and describes production of a final product with an apparent density of 11 pounds per cubic foot, 2.2 pounds of which is asbestos fiber.

The examiner rejected all of the appealed claims as “being unpatentable over Fraser.” The examiner stated, without apparent dispute by appellant, that the product of Fraser’s Example II falls “within the range of 16-70 percent of voids” as set forth in the appealed claims. With regard to the differences in fiber lengths and void shapes in the articles disclosed by Fraser and those claimed by appellant, the significance of which appears to be the main point at issue, the examiner stated:

“ * * * Applicant has failed to show anything critical to result from his range of fiber lengths (which includes 0.3 centimeters) when the fibers of Fraser may have a length of 0.2 centimeters. Nor is anything critical seen in applicant’s spherical voids compared to the elongated voids of the reference.”

The board sustained the examiner’s rejection. Noting that appellant urges the significance of the spherical character of the voids in his claimed product, the board stated: 2

“We find no use of the term ‘spherical’ in describing the voids, in this application as filed. Rather, we find them described only as ‘independent non-communicating air or gas-filled cells’ * * *, as opposed to acknowledged prior art voids ‘in the form of interconnecting capillaries,’ * * *. Appellant is not, therefore, in a favorable position to urge patentability on the basis of the said term. Moreover, Fraser, in describing his product, distinguishes his voids from ones that are ‘completely surrounded or occluded’ (column 13), as we have noted above, and as having certain advantages with respect to them (column 4, lines 21-26), and thus has a clear teaching of the noncommunicating type of voids, and of the results they will give in the fibered product he discloses.”

The board also stated:

“We do not believe that the claimed fiber length of three-tenths of a centimeter patentably distinguishes from the reference length of two-tenths of a centimeter.”

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Bluebook (online)
300 F.2d 945, 49 C.C.P.A. 1015, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-sidney-dilnot-ccpa-1962.