DECISION OF THE COMMISSIONER
STATUTORY: Section 2(d) Measuring moisture content
INEXPLICIT: Claims are incomplete.
Rejection under Section 2(d) was in conformance with Patent Office
guidelines at the time the action was written. This is now
withdrawn due to a change in directed policy.
A capacitor probe measuring arrangement will measure the moisture
content of a material independent of the mass, provided the probe
voltage is balanced. Three claims not showing any balancing
means are incomplete as they fail to recite an essential feature
for the proper operation of the invention.
FINAL ACTION: Modified.
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IN THE MATTER OF a request for a review by the
Commissioner of Patents of the Examiner's Final Action
under Section 46 of the Patent Rules.
AND
IN THE MATTER OF a patent application serial
number 923,991 filed February 23, 1965 for an invention
entitled:
MOISTURE MEASURING SYSTEM EMPLOYING PHASE COMPARISON
Agent for Applicant
Messrs. Alex E. MacRae & Co.,
Ottawa, Ontario.
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This decision deals with a request for review by the
Commissioner of Patents of the Examiner's Final Action dated
August 20, 1971 on application 923,991. This application was
filed in the name of Alan Norwich and refers to "Moisture
Measuring System Employing Phase Comparison".
In the prosecution terminated by the Final Action the
examiner rejected claims 1 to 4 and 10. The reasons for such
rejection are that claims 1 to 3 define a method outside the
statutory field of invention and that claims 1, 4 and 10 do not
explicitly define a patentable invention over the prior art.
In the Final Action the examiner stated: (in part)
The Chun et al patent relates to a modification of
electrical resistivity well logging in which a
further electrode is provided to pick up a capacitively
induced signal varying in amplitude and phase with the
characteristics of the formation being surveyed.
Applicant's attention is brought to Chun et al's use of
tubes 18 and 18' (figure 1) the grids of which are
biased by the "C" battery 25 so as to operate the
tubes as grid controlled rectifiers. This arrange-
ment produces, in fact, the same effect as the diode
arrangement of applicant's claim 10, Chun et al are
not concerned with the effects of the mass of the
sample and, in fact, are concerned with a sample of
infinite extent. Consequently the step of comparing
the phase of the output signal with the phase of the
applied signal, as followed by Chun et al does not
produce a resultant signal which is independent of the
mass of the material as set out in the rejected claims.
The remaining claims, distinguish over the cited refer-
ence by reciting means to balance out "from said output
signal any effect of the capacitance between said
material", in the determination of the property of a
dielectric material "independent of its mass".
Claims 1 to 3, inclusive, are further rejected since
it is held that these claims are outside the statutory
field of invention as defined by Section 2(d) of the
Patent Act. These claims are held to be directed to
an unpatentable non-manufacturing method, that is a
method for determining a property of a dielectric
material, and, specifically, for measuring the moisture
content of an article.
In applicant's response of November 17, 1971 he stated:
(in part)
It is believed to be a fair statement of the Examiner's
position that while claim 1 distinguishes over U.S.
patent 2,446,527 in reciting that the resultant
signal is "indicative of said property independently
of the mass of said material", the Examiner considers
this distinction is insufficient to support the
patentability of the claim. The Examiner also considers
the similar recitations in claims 4 and 10 to be in-
sufficient to render the claims patentable over the
Chun et al reference.
This application discloses a method and apparatus for
measuring the moisture content of a continually moving
sheet, such as paper, which has a variable mass per
unit area in addition to a variable moisture content.
The material is positioned adjacent to a capacitor probe
and the phase shift in the signal from the probe is
indicative of the moisture content of the material and
substantially independent of the mass of the material.
This is because the shift in phase is occasioned by a
time delay dependent upon the product of the equivalent
resistance and equivalent capacitance added by the
introduction of material to the probe. When the
relative moisture content changes, the resistance and
hence the product changes, but when the mass changes,
the resistance and capacitance change in opposite
directions, leaving the product substantially un-
changed, For example, doubling the material at the
probe will cut the resistance substantially in half
while substantially doubling the added capacitance.
The applicant also objected to the refusal of claims 1-3
as nonstatutory in that, "the method produced a beneficial result
which is of commercial or economic value, or of practical signifi-
cance and is related to a form of manufacture."
Having considered the ground of rejection, "Claims 1-3
define a method outside the statutory field of invention",I
find that this stand was generally in conformance with guidelines
at the time the Final Action was written. However, in the present
circumstance it has since been decided that this is not a proper
ground of rejection and the rejection based on this ground will be
withdrawn.
The second ground of rejection is based on the examiner's
contention that claims 1, 4 and 10 do not explicitly define a
patentable invention over the following prior art, namely: United
States Patent, 2,446,527, August 10, 1948 C1. 175-182, Chun et al.
This patent relates to a modification of electrical
resistivity well logging in which a further electrode is
provided to pick up a capacitively induced signal varying in
amplitude and phase with the characteristics of the formation
being surveyed.
In accordance with the present invention, a single
measurement at a single frequency is used to measure moisture
content. It has been discovered that when the dielectric
material to be measured is placed in a capacitance probe and
the effect of the empty probe is eliminated, the phase shift of an
applied signal as produced by the material is independent of
variations in the mass of the material and is a measure of
relative moisture content independent of the mass. Claim 1
reads as follows:
A method for the quantitative determination of a
property of a dielectric material independent of its
mass, said method comprising applying an alternating
current electrical signal to at least a portion of the
material, deriving an output alternating signal
resulting from the applied signal as this applied
signal is influenced by the mass of said material
and the dielectric properties of said material, and
comparing the phase of said output signal with the
phase of said applied signal independently of the
magnitudes of said output and applied signals to
produce a resultant signal indicative of the differ-
ence in phase occasioned by said material and so
correlated and calibrated with respect to said applied
and output signals that it is indicative of said
property independently of the mass of said material.
On considering the question of whether Claims 1, 4 and 10
do not explicitly define a patentable invention, I note certain
observations set out in the disclosure and more particularly at
page 3 line 24 to the effect that:
The balancing capacitor 26 is adjusted so that the
phase inverted signal through the capacitor 26 just
balances the direct signal through the probe 12 in
the absence of material at the probe. This balances
out from the output signal the effect of no load
capacitance of the probe, i.e. the capacitance of
the probe in the absence of material. Under such
circumstances, when material is placed in the probe,
the phase of the signal developed on the bridge
output terminal 22 is shifted from the phase of the
input signal from oscillator 10 by an amount related
to the relative moisture content of the material
and substantially independently of the mass of the
material. This is because the shift in phase is
occasioned by a time delay dependent upon the
product of the equivalent resistance and equivalent
capacitance added by the introduction of material
to the probe. When the relative moisture content
changes the resistance and hence the product changes,
but when the mass changes, the resistance and
capacitance change in opposite directions, leaving
the product substantially unchanged. For example,
doubling the material at the probe will cut the
resistance substantially in half while substantially
doubling the added capacitance.
Vector diagrams may be drawn by the well known methods of
electrical engineering to illustrate the effect of the change in
the phase angle as the conditions change. It is understood that
is without the voltage drop being considered; or the same
result is obtained when the probe voltage is balanced out as
the disclosure teaches. The phase angle will change due to the
presence of the probe and also that phase angle changes will
result from both the probe and the change in mass. Therefore,
unless the capacitance of the probe is eliminated by balancing
out this voltage the dielectric property cannot be determined
independent of the mass of the material being tested.
I also quote from the applicant's response of December
21, 1966, "...one could not say that the system is inoperative
if the probe-balance feature is omitted. Such omission results
in the device being sensitive to mass variations,"rather than
independent of its mass variations.
It is noted that the remaining claims either recite a
method or means to balance out "from said output signal any
effect of the capacitance between said material", in the
determination of a property of a dielectric material "independent
of its mass".
It is clear that the elimination of the effect of the
empty probe is, part of the overall concept of the invention.
Therefore, I find that the objection of the examiner on the
grounds that claims 1, 4 and 10 are "inexplicit" is correct
to the extent that the claims are incomplete. As I see it,
applicant cannot state at the end of these claims, "...
independent of the mass", unless he recites an essential
feature to obtain such a result; i.e. "the balancing out
from said output signal the effect of the capacitance
from said probe means in the absence of said material."
I am, therefore, satisfied that claims 1, 4 and 10 do
not claim the invention disclosed in distinct and explicit
terms by failing to recite an essential feature for its
operation. I recommend that this ground of rejection be
upheld and further that the ground of rejection with respect
to unstatutory subject matter be withdrawn.
R. E. Thomas,
Chairman, Patent Appeal Board.
I concur with the decision of the Patent Appeal Board and
confirm the rejection of claims 1, 4 and 10 on the grounds of
being inexplicit and I withdraw the rejection under Section 2(d)
of the Patent Act. Applicant has six months in which to appeal
this decision in accordance with Section 44 of the Patent Act.
Decision accordingly,
A.M. Laidlaw,
Commissioner of Patents.
Dated at Ottawa, Ontario,
this 4th day of January, 1972