31. Reexamination has been ordered following receipt of a request for reexamination of U.S.
Patent X, filed by the patentee. Patent X contains independent claims 1 through 4, each directed
to a hydrocyclone separator apparatus. They are the only claims that were ever presented during
prosecution of the application that matured into Patent X. In the first Office action during
reexamination, claims 1 through 4 are rejected as being obvious under 35 USC 103 over U.S.
Patent Z. The apparatus is used for separating material, including fibers suspended in a liquid
suspension, into a light fraction containing the fibers, and a heavy fraction containing rejects.
Assume there are no issues under 35 USC 102, 103, or 112, and that any dependent claim is
properly dependent. Recommend which of the following claims, if any, would be subject to
rejection under 35 USC 305 for improperly enlarging the scope of the original claim in
accordance with the patent laws, rules and procedures as related in the MPEP.
(A) Claim 5. A hydrocyclone separator apparatus according to claim 4, wherein said
blades are configured in the form of generally plane surfaces curved in one plane
only.
(B) Claim 5. A hydrocyclone separator apparatus according to claim 4, wherein the
outlet duct is in the form of two frustro-conical portions joined at their narrow
ends.
(C) Claim 5. A method of separating material including fibers suspended in a liquid
suspension comprising the steps of separating the material into a light fraction
containing the fibers and a heavy fraction containing rejects, and converting the
light fraction into a pulp and paper stock suspension.
(D) Claim 5. A hydrocyclone separator apparatus according to claim 4, wherein the
separator chamber is conical in shape having at the narrow end an outlet for the
heavy fraction and at its wide end an outlet for the light fraction.
(E) None of the above.

31. ANSWER: (C). 35 U.S.C. § 305; MPEP §§ 2258 and 1412.03. MPEP § 2258, under
the heading “Claims In Proceeding Must Not Enlarge Scope Of The Claims Of The Patent,”
states “[w]here new or amended claims are presented . . . the claims of the reexamination
proceeding should be examined under 35 U.S.C. 305, to determine whether they enlarge the
scope of the original claims. 35 U.S.C. 305 states that ‘no proposed amended or new claim
enlarging the scope of the claims of the patent will be permitted in a reexamination
proceeding…’.” Under the further subheading “Criteria for Enlargement of the Scope of the
Claims,” MPEP § 2258 states “A claim presented in a reexamination proceeding ‘enlarges the
scope’ of the claims of the patent being reexamined where the claim is broader than each and
every claim of the patent. See MPEP § 1412.03 for guidance as to when the presented claim is
considered to be a broadening claim as compared with the claims of the patent, i.e., what is
broadening and what is not. If a claim is considered to be a broadening claim for purposes of
reissue, it is likewise considered to be a broadening claim in reexamination.” MPEP § 1412.03,
under the heading “New Category of Invention Added In Reissue – Broadening,” states “[t]he
addition of process claims as a new category of invention to be claimed in the patent (i.e., where
there were no method claims present in the original patent) is generally considered as being a
broadening of the invention. See Ex parte Wikdahl, 10 USPQ2d 1546, 1549 (Bd. Pat. App. &
Inter. 1989).” MPEP 2258, under the further subheading “Rejection of Claims Where There Is
Enlargement,” states “[a]ny claim in a reexamination proceeding which enlarges the scope of the
claims of the patent should be rejected under 35 U.S.C. 305.” Since no claims drawn to a
method were ever presented during prosecution of Patent X (claims 1 through 4 “are the only
claims that were ever presented during prosecution of the application that matured into Patent
X”), the claim recited in (C) is not directed to “the invention as claimed.” (A), (B), and (D) are
all incorrect because each of their claims are directed to a hydrocyclone separator apparatus, i.e.,
“the invention as claimed,” and they do not enlarge the scope of the claims in Patent X. (E) is an
incorrect answer because (C) is the correct answer.