COMMISSIONER'S DECISION
UNOBVIOUS: Preferred Embodiment Clears Prior Art.
A pipe disclosed for transporting fluid with rotational flow
produced by helical ribs on the inner surface of the pipe, the
ribs having specified pitch and height dimensions and "sharp
and pointed" innermost tips was shown by the citations including
the purpose of "mixing" the fluid. The embodiment with the
added feature of the helices extending in opposite directions
in successive sections of the pipe not taught by the prior
art is patentable.
FINAL ACT10N: Affirmed in-part; some of the amended claims accepted.
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This decision deals with a request for review by the Commissioner
of Patents of the Examiner's Final Action dated February 26, 1973
on application 097,780. This application was filed on November 10,
1970 in the name of Hideo Takeda and refers to a "Method of and
Apparatus for Transporting Fluid." The Patent Appeal Board
conducted a hearing on January 23, 1974, at which Mr. R.D. Mackenzie
represented the applicant.
This application relates to an apparatus for transporting fluid
comprising a pipe having helical protrusions on the internal
surfaces thereof which cause fluid transported therethrough to
rotate about the axis of the pipe. This prevents sedimentation
of solids in the fluid. The protrusions are so shaped as to
produce that result.
In the prosecution terminated by the Final Action the examiner
refused the application on the ground that the subject matter is
obvious in view of references cited, and as coming within the
ordinary skill of workmen in the art.
In the Final Action the examiner stated in part:
This application stands rejected in that the subject matter
set forth is that which could be expected from one having
ordinary skill in the art to which the alleged invention
pertains in view of the following applied references. The
differences over the prior art world he obvious to a skilled
workman.
References Re-Applied
Canadian Patent
101,500 October 16, 1906 Cl. 302-32 Dwgs. 1 sht. Milne
United States Patents
2,661,194 December 1, 1953 Cl. 259-151 Katovsich
2,095,242 October 12, 1937 Cl. 158-74 Dick
Each of the above references shows various means of a helical
configuration on the inner surface of a material carrying conduit
to effect a spiral flow of the contents within the conduit to
facilitate flow therethrough.
Applicant's claims differ over the noted prior art by having a
smooth transition area between the inner wall of the conduit and
the body of the helical protrusion. Such a distinction is held
to be a mere matter of choice and elementary design. It is obvious
that in the interest of facilitating a helical flow of the material
the areas which the material contacts should be smooth to thereby
prevent or minimize fluid turbulence which is occasioned by a
sharp corner or the like. Thus to eliminate any sharp areas in
the prior art would be but expected skill. To give the protrusion
a pointed edge is held to be a mere matter of choice and elementary
design. Nothing of an unobvious nature results because of the
pointed configuration. The crucial factor quite clearly the same
between the instant device and the prior art is the helical flow
occasioned by a helically configured insert. To arrange feeding
equipment at spaced locations along a main line with connectors
at each location to tie the auxiliary equipment to the main line
is held obvious in view of the well known plumbing field which
employs such a technique in tying a plurality of feeder lines
into a main line. To arrange for the helical direction to be
reversed between adjacent connected conduits is held to be a
mere matter of choice, nothing of an unobvious nature resulting
because of the choice and no new result being effected.
The applicant in his response dated May 3, 1973 to the Final Action
stated in part:
As pointed out in the introduction to newly submitted claim 1,
the pipe of this invention has at least four beneficial effects.
Specifically, it minimizes precipitate on an internal surface
of the pipe. As compared to a cylindrical pipe in experiment
1, there was a 10 to 1 reduction in precipitate.This is a
particular problem at low Reynolds numbers, i.e. below 23,000
in the condition of laminar flow. Please note that most of the
references have turbulent flow and higher Reynolds numbers. A
second important effect is the minimizing of accummulation of
gas bubbles in the upper portion of the pipe. This is also a
particular problem with low Reynolds number, in the laminar flow
region. A third effect is accelerating mixing of the liquid or
other fluid. A fourth and most important effect is promoting
a piston flow condition.
These four beneficial effects are obtained with the specific
construction illustrated and disclosed in the application,
and recited in newly submitted claim 1. That is, not only
must there be a cylindrical tubular pipe with a helical rib,
but the pitch of the helix must be larger than half the
internal diameter of the pipe, otherwise there is not the
mixing and turbulent flow results. Moreover, the height
of the helix must be between 1/6 and 1/2 the internal
diameter of the pipe. If the helix is below 1/6, the effect
does not obtain the degree desired and if it is above 1/2,
the same occurs, Initially, the helical protrusion or rib
has symmetrical streamline services to aid the laminar flow
and more importantly to merge into sharp tips of the protrusions
which reduce the volume of the protrusions in comparison to the
total volume of the inside of the pipe. This results in a lose
pressure drop in the pipe as compared to an ordinary pipe with
convention helices.
...
Lastly, it is submitted that the subject matter of the claims
presently on file is not obvious from the reapplied references
taken in combination. As discussed above and in the previous
responses, none of the reapplied references disclose protrusions
having a structure or shape as recited by the applicant, without
which the desired operation cannot be obtained, as described in
the disclosure.
The question to be decided is whether the subject matter of the
present application can be considered as a patentable advance in
the art.
A pipe for transporting fluid with rotational flow, minimizing
precipitate on an internal surface of the pipe, minimizing
accumulation of gas bubbles in the upper portion of the pipe,
while accelerating mixing of the fluid and promoting a piston
flow condition, the pipe comprising:
a) a cylindrical tubular pipe having an inner surface
and an outer surface,
b) a rib-like protrusion extending inwardly from the
inner surface of the pipe and positioned along a helix
on the inner surface of the pipe,
c) the pitch of the helix being greater than one-half
the internal diameter of the pipe,
d) the height of the rib-like protrusion being between
one-sixth and one-half the internal diameter of the pipe,
e) the protrusion having streamlined symmetrical side
surfaces merging into the internal surface of the pipe,
and
f) the innermost tip of the protrusion being sharp
and pointed in section.
The primary reference, Katovsich, relates to mixers for use in
a jetting apparatus, and mare particularly to a mixer for
materials such as concrete, which are discharged at high pressure
and velocity as a jet. The primary objective of this invention
is to assure the uniform and accurate mixing of liquid and dry
constituents of a material to be discharged as a jet under
pressure. For a more complete description we turn to the
disclosure, page 2 starting at line 31,which reads:
My improved mixer is best illustrated in Figs. 2 and 3
and comprises a metal sleeve or tube 32 which is split
longitudinally along the parting plane 34 and whose
parts or sections include radially outwardly projecting
longitudinal flanges 36. The flanges 36 are apertured
to receive securing members 38 for fixedly securing the
sleeve parts together in register in a manner to with-
stand the application of high. pressure and to withstand
impact. The flanges 36 preferably terminate spaced
from the ends of the sleeve sections, aid the terminal
portions of the sleeves are preferably provided with
exterhal screw threads 40 outwardly of the ends of the
flanges 36.
Also, claim 1 of the reference reads:
A mixer for mixing solids and a liquid and adapted to
be interposed in a conduit, comprising a rigid tubular
housing having a smooth inner surface and means at
each end for attachment to a conduit, and a tubular
liner formed of resilient material and having a
plurality of spaced integral inwardly projecting
helical ribs of substantial height extending for
substantially the full length of said liner, the
inner edges of said ribs outlining a central passage
through said liner.
The Milne reference discloses a tubular conveyor for "Peat
Collecting Machines" with means to prevent the lodging of peat
in the lower internal periphery of the tube. This means
consists of one or more convolute or spiral wings secured to
the interior of the tube.
The Dick reference discloses a tubular conveyor pipe for use
in 1 fuel burner with means to aid in the mixing of the fuel.
This means consists of convolute or spiral projections secured
to the interior of the conveyor pipe.
One difference between the prior art and amended claim 1 which
the applicant claims is significant is the pitch relationship
to the diameter of the pipe, which is claimed as "being greater
than one-half" of the internal diameter of the pipe. Another,
is the height of the protrusions which are one-sixth to one-half
the pipe diameter. Also considered of significance is the
symmetrical streamlined surfaces of the protrusions which
merge into pointed edges.
The applicant argues that the pitch of the helix of Katovsich
is "less than one-half of the internal diameter" of the pipe.
However, figure 3 in the Katovsich reference clearly shows that
if we follow the spiral configuration of each protrusion we
find that the pitch is within the limits set forth by the applicant,
keeping in mind that "greater than one-half" is a broad limit,
and that the drawings are illustrative only. Also the height
of the ribs in the present device "is desired to be larger
than one-sixth and smaller than one-half of the diameter of
the pipe". It is noted that this is a desired limit only. On
the other hand, the Katovsich ribs are "approximately one-forth
inch" in a bore diameter of approximately one and three quarter
inches.
With respect to "the streamlined surfaces which merge into pointed
edges" the disclosure, amended page 2 beginning at line 14, reads:
"...and the protrusions are preferred to have symmetrical inwardly
concave streamlines on both sides in its vertical cross section
with a pointed edge on the internal surface of the pipe." It is
admitted that the primary reference, Katovsich, does not show the
pointed edges, nor does it have the same angle of merger with the
side walls as that disclosed in the present application. However,
as previously noted from the disclosure "the protrusions are
preferred to have...a pointed edge...."
The applicant argues that his invention minimizes precipitate on
the internal surface of the pipe. However, Katovsich and Milne
teach the use of a structure to mix thoroughly the matter therein.
Dick also uses his helical structure to vaporize thoroughly the
mixture therein.
The applicant argues that "the mixing effect is accelerated since
the whole fluid rotates about the axis of the pipe." This however,
according to the disclosure, was only in comparison to a standard
cylindrical pipe. The references, especially Katovsich, teach
that the mixing effect is accelerated by the helical protrusions
on the internal surface of the pipe.
The applicant also argues that "there is little longitudinal
dispersion of fluid in the order in which each portion has been
sent therein, that is, the fluid flows through the pipe under a
so-called piston flow condition." Once again in our view this
is a natural occurence under the conditions set out in the prior
art.
The disclosure on page 4 describes an experiment, for example,
where the helices are directed in the same direction in a pipe
(i.e. claim 1). On this point line 33 reads: "The measured
precipitate was about 10 gr. in the (standard) cylindrical
pipe and about 1 gr. in the helical pipe." Therefore, there
is a very noticeable lack of precipitate when the helical pipe
is used as compared to the standard pipe. This improvement,
however, is the natural result expected from the teachings of
the cited prior art, which disclose the use of helical type
pipes.
Claim 1 therefore, in our view, does not cover a patentable advance
in the art. Claims 2, 3 and 4, which are dependent on claim 1
merely add limitations of no significance, such as the number of
ribs and the relationship of the helices to the inside of the
pipe. Accordingly, our comments about claim 1 apply equally to
claims 2, 3 and 4.
The combination covered by claim 5, however, (considering that it
depends on claims 2 and 1) is not taught nor suggested by the prior
art. Claim 5 reads:
A pipe as defined in claim 2 wherein the helices extend
in opposite directions in different sections of the pipe.
The disclosure on page 6 describes, for example, an experiment
where the helices extend in the opposite direction in different
sections of the pipe (i.e. claim 5) and reads: "On the other
hand, in the case of the helical pipe in accordance with the
invention, the turbid liquid was seen only near the adding nozzle
(from 5 to 6 cm. from the nozzle) and further downstream from the
solution was completely mixed and became transparent." Thus, it
is seen that the solution was completely mixed when the apparatus.
was arranged with the helices in opposite direction in different
sections of the pipe. This discloses a practical advance in the
art. Furthermore there is no indication that the extension of the
helices in opposite directions in different sections of the pipe
would be an obvious alteration to make. Claim 5 therefore, in
our view is acceptable. If any amendments are contemplated,
however, the applicant might consider Canadian patents 811,022
and 772,959, and United States Patent 3,117,821.
Claim 6, which is dependent on claim 1, adds means for introducing
fluid into a pipe. In the absence of patentable subject matter
in claim 1, claim 6 in such circumstances also lacks patentable
subject matter. It is suggested, however, that claims 3, 4 and 6
if re-numbered, could be made dependent on claim 5 when it is
rewritten as new claim 1.
The Board is satisfied that claims 1, 2, 3, 4 and 6 do not disclose
a patentable advance in the art. Claim 5 in our view, however,
discloses a patentable advance in the art.
The Board therefore recommends that amended claims 1, 2, 3, 4 and 6
be refused, but that claim 5, if presented in independent form as
claim 1, should be considered for allowance. Other claims mentioned
above, if made dependent on an amended claim 1, would also
be acceptable.
J.F. Hughes,
Assistant Chairman,
Patent Appeal Board.
I concur with the findings of the Patent Appeal Board. Accordingly,
I refuse to grant a patent on the subject matter of amended claims 1,
2, 3, 4 and 6, but will accept claim 5 when presented in independent
form, and other suitably dependent claims. The applicant has six
months within which to delete claims 1, 2, 3, 4 and 6 and present an
appropriate amendment, or to appeal this decision under the provisions
of Section 44 of the Patent Act.
Decision accordingly,
A.M. Laidlaw,
Commissioner of Patents.
Signed and dated in
Hull, Quebec this
18th day of February, 1974.
Agent for Applicant
George H. Riches and Associates,
Toronto 1, Ontario.