COMMISSIONER'S DECISION
OBVIOUSNESS: Method Claims Fail in View of Prior Art.
The application relates to an apparatus for spraying powdered
materials at low controlled rates. The prior art failed to teach
or suggest the combination in rejected apparatus claims. The
method claims, by contrast, failed to recite that relationship,
and were considered too broad in scope, though they could be
modified to overcome the rejection.
FINAL ACTION: Modified.
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This decision deals with a request for review by the Commissioner
of Patents of the Examiner,s Final Action dated October 23, 1974
on application 141,564 (Class 302-25). The application was filed
on May 8, 1972 in the name of Robert G. Coucher and is entitled
"Powder Feeder and Methods for Transporting Particulate Material."
This application relates to a powder feeder, especially useful for
spraying powdered materials at low controlled rates. The feeder
is provided with an orifice to admit gas up through the bottom at
a high velocity. A pair of concentric conduits are suspended from
the top of the feeder in approximately axial alignment with the
orifice so that the column of gas is captured within the outer
conduit and substantially all enters the inner conduit. The
powdered material is stored in the space between the outer conduit
and the wall of the feeder. The spacing of the outer conduit from
the bottom of the feeder is adjustable to admit the powdered
material in a controlled manner to the vicinity of the orifice.
The inner conduit is also adjustable with respect to the outer
conduit as an added control. When gas is forced through the
orifice, the powdered material is lifted by the venturi pressure
effect created by the gas.
In the Final Action the examiner refused claims 1,2, 4 to 7 and
9 to 12 for lacking invention over the following references:
French Patent
947,479 June 10, 1947 BOURDILLON
United States Patent
3,501,602 March 17, 1950 De Witt
In that action the examiner stated (in part):
Claims 1, 2, 4-7 and 9-12 in this application stand rejected
for failing to define a clear inventive step over the French
Patent in view of the United States Patent. To arrange the
teaching of the French Patent for use in a closed vessel is
held to be a mere matter of expected skill. The United
States Patent shows that closed vessels are known. To adapt
the teaching of the French patent for use in known closed
systems is held to be a mere matter of expected skill and
normal engineering. To vibrate the vessel to facilitate feed
is held to be but expected skill and common knowledge in any
event. No claimed features in claims 1, 2, 4-7 and 9-12 are
seen to be beyond choice, elementary design or expected skill.
The applicant in his response dated October 23, 1974 to the Final Action
Stated (in part):
...
It would appear that the Examiner considers the sleeve 10
(shown in the French patent) to be the equivalent of the
first conduit defined in applicant's claim 1 and the tube
9c to be the equivalent of applicant's second conduit.
Applicant agrees that the United States patent teaches a
closed vessel and judging from the drawing of the French
patent it would appear that the most logical manner of
closing the French vessel would be to place a cover over
the spider members which space the outer cylindrical wall
of the vessel from the inner cylindrical threated portion
indicated at 10c. Since the wheel 10b is intended to
rotate the sleeve 10 it would certainly not be practical
to enclose that wheel 10b in a closed vessel since the ease
of adjustment now achieved with the French apparatus would
be completely lost....
...
Turning now to the method claims 9 to 12, applicant is again
unable to agree that these claims are obvious in view of the
prior art. Unfortunately, the Examiner has not advanced any
specific arguments with respect to the method claims.
However, applicant strongly believes that the method of claims
9 to 12 is distinct from the prior art. In the United States
patent, for example, metering is accomplished by adjusting the
gap 86 between the ring 82 and the top of the member 60.
Metering, as set forth in claim 9 of the present invention, is
accomplished by adjusting the vertical and horizontal spacings
of the barrier from the orifice. The physical phenomena
involved in the two methods are very different. In the refer-
ence, the material adjacent to the member 60 must be fluidized
or it will not flow to the vicinity of the orifice. The
method of claim 9 relies only on the inherent angle of
repose of the material for rate control. Energizing the
material to the extent taught by the reference would be
detrimental because once a material is fluidized it
obviously cannot exhibit a stable angle of repose. Hence
there would be no predetermined flow of material under
the barrier (30a, Figure 1) downward to the vicinity of
the orifice 39 as required by claim 9. The remaining
claims 10 to 12 are certainly not found in the United
States patent.....
The Bourdillon reference relates to an apparatus for depositing powder,
or dust, in suspension in a current or stream of gas. The apparatus
comprises a vessel in which the powder can be stored; an orifice opening
into the vessel from its bottom; a conduit mounted in the vessel in
axial alignment with the orifice and an adjustable sleeve surrounding
the conduit to control the feed of the powder.
The De Witt reference was cited to show the use of a "closed vessel"
powder feeder working on the same general principle as that shown in
Bourdillon.
The state of the prior art was also discussed by the applicant on page 1,
2nd para, of the disclosure and reads:
.... The pneumatic conveying of finely divided, particulate
material is conventional. The venturi principle is employed
in various commercial equipment for drawing particulate
material from a reservoir into a moving stream of gas or
liquid. Such techniques have not heretofore been success-
fully applied to the uniform transport of particulate
materials at low rates, however.
Heretofore, for applications requiring uniform feeding of
a powdered material, e.g. to a plasma flame for plasma
flame spraying of a substrate, various types of mechanical
feeders have been relied upon. At very low rates, mechanical
feeders become erratic, however. Limitations imposed by the
mechanics of such feeders make it impractical to feed powders
from a stock at rates much below about a pound per hour. Many
potential applications exist for well-controlled, uniform,
lower feed rates, but it has not heretofore been practical to
achieve them.
As mentioned, this application relates to a powder feeder, especially useful
for transporting particulate materials at a low controlled rate. A container
is provided with an orifice to admit gas up through the bottom of the
vessel in a high velocity column or jet. A pair of concentric conduits
are suspended from the top of the vessel in approximately axial align-
ment with the orifice so that the column of gas is captured within
the outer conduit and substantially all enters the inner conduit.
Particulate material (such as metal powder) is stored in the space
between the outer conduit and the wall of the vessel. The spacing
of the outer conduit from the bottom of the vessel is adjusted to
admit particulate material to the vicinity of the orifice at a
controlled rate. When gas is forced through the orifice, particulate
material is lifted by the venture pressure effect created by the gas
column. Claim 1 reads:
Apparatus comprising: a closed vessel with an interior;
means for introducing particulate material to the interior
of said vessel;
an orifice, opening into the vessel from its bottom,
oriented to admit gas forced therethrough in an upwardly
directed jet stream into the interior of said vessel;
an outlet at the top of said vessel;
a first conduit, mounted within the vessel in approximately
axial alignment with said orifice, with the lower end of
said first conduit directly above said orifice and suffi-
ciently near the bottom of the vessel to prevent powder
contained within the vessel from filling the space between
said lower end and said orifice, and with the upper end of
said first conduit in open communication with the interior
of said vessel; and
a second conduit of smaller cross section than said first
conduit mounted within and in approximately axial alignment
with said first conduit with the lower end of said second
conduit directly above said orifice and the upper end of
said conduit openly communicating with said outlet.
The question which the Board must consider is whether claims 1, 2, 4 to
7 and 9 to 12 should be refused as lacking patentable subject matter
over the art cited.
First it is observed that in order to refuse for lack of inventive
subject matter, the prior art when taken collectively must substantially
teach the combination as claimed.
The applicant has stated that he has overcome a problem of feed control
at low feed rates. He maintains that: "Limitations imposed by the
mechanics of such (prior art) feeder make it impractical to feed
powders from a stock at rates much below about a pound per hour (see
page 1 of the disclosure). On the other hand, the second last
sentence, on page 3, reads: "...the invention is of particular
interest, at the present time, because of its unique capability of
transporting such materials at very low rates. The preferred
embodiment of the apparatus may be adjusted to deliver particulate
material at feed rates ranging from a fraction of a gram up to
several pounds per hour." There is no reason apparent to discredit
the applicant's claim to have solved that problem, as it is well
documented by the results of a number of experiments which appear
in the disclosure.
We will now consider the rejected claims.
The first portion of claim 1, a vessel, an orifice, an outlet at the
top of the vessel and a conduit are shown by Bourdillon. The
applicant does, however, claim a "closed" vessel, but this is shown
by De Witt. The last portion of the claim reads: "...a second
conduit of smaller cross section than said first conduit within and
in approximately axial alignment with said first conduit with the
lower end of said second conduit directly above said orifice and
the upper end of said second conduit openly communicating with said
outlet."
There is no teaching in the cited art wherein a second conduit is
coaxially contained within a first conduit. A conduit, by definition,
is a tube or channel which is adapted to carry a fluid. Since the
applicant uses two conduits coaxially aligned the construction must,
by definition, provide an annular space between the first and second
conduits for the passage of fluid or air therebetween. The Bourdillon
reference on the other hand shows an outer cylindrical casing, which
can only be considered as a sleeve for the purpose of adjusting the
quantity of powder to the orifice. The claim also brings out the
fact that "the first conduit (is) in open communication with the
interior of said vessel." That arrangement has a particular role to
play as explained in the last paragraph on page 5 of the disclosure,
which reads "The inner conduit should be of sufficient cross section
to receive most of the gas column rising up from the orifice. It
should be sufficiently smaller than the other conduit to define an
annuar space capable of passing the gas and suspended powder which
fails to enter the inner conduit without clogging."
In our view therefore, the combination of claim 1 is not taught nor
suggested by the cited art. The applicant has in our view produced
a result in a more expedious manner than had apparently been done
before. Accordingly, the Board is satisfied that there is in the
new combination claimed a degree of ingenuity which was the result
of thought and experiment. (See Crossley Radio Corporation v.
Canadian General Electric Company (1936) S.C.R. 551 at 560. It
follows that the rejection of claim 2 and 4 to 7, which depend on
claim 1, is also traversed.
The examiner also refused method claims 9 to 12. Claim 9 reads:
A method for transporting finely divided, particulate
material at a controlled rate, which comprises:
establishing and maintaining a column of gas flowing
up from an orifice of selected cross section at high
velocity;
positioning a quantity of the finely divided, particulate
material so that it tends to flow toward said orifice;
providing a barrier between the gas column and the par-
ticulate material, located to permit passage of such
material beneath said barrier at a region spaced
vertically up and horizontally out from said orifice at
distances selected to permit a predetermined flow of
particulate material to the vicinity of said orifice; and
capturing the gas column above the orifice for transport
to a remote location.
That claim recites the steps of: maintaining a column of gas from
an orifice; providing a quantity of particles in a controlled manner
and transporting the particles to a remote location by means of the
gas column. These steps are clearly inherent in the Bourdillon
reference. In other words that claim does not include the essential
features of the invention; namely, a first and a second conduit
coaxially aligned, which feature is argued by the applicant, as
noted above, to be an important part of his advances in the art. It
is observed that the claim refers to "a barrier," but not the specific
barrier "an outer cylindrical conduit," and as a result reads on the
"sleeve barrier" of Bourdillon. It is really a matter of the claim
failing to comply with Section 36(2) of the Patent Act.
Claims 10 to 12, which depend on claim 9, also fail to recite the first
and second conduit relationship. The same arguments used to refuse
claim 9 therefore, apply equally to claim 10 to 12.
The Board is satisfied that rejected claims 1, 2 and 4 to 7 recite a
patentable advance in the art over the references cited, and we
recommend that the rejection be withdrawn.
The Board is also satisfied that claims 9 to 12 fail to recite a
patentable advance over the art cited, and we recommend that the
rejection of claim 9 to 12 be affirmed.
J.F. Hughes,
Assistant Chairman,
Patent Appeal Board.
I concur with the findings of the Patent Appeal Board and withdraw
the rejection against claims 1, 2, and 4 to 7, but refuse to allow
claims 9 to 12. The applicant has six months within which to delete
claims 9 to 12, to amend along the guidelines suggested, or to
appeal this decision under the provision of Section 44 of the
Patent Act.
Decision accordingly,
J.A.Brown
Acting Commissioner of Patents
Dated at Hull, Quebec
this 7th day of May, 1975
Agent for Applicant
A.E. MacRae & Co.,
Ottawa, Ontario.