COMMISSIONER'S DECISION
Section 36(2); Obviousness
Control System for an Air Conditioner
An air conditioner utilizes a compressor-expander in a closed loop, with a
primary heat exchanger in an ambient atmosphere, and a secondary heat ex-
changer in an enclosed space. A source of auxiliary air is injected into
the loop to provide varying pressures. The Final Action was withdrawn
because the claims avoid the cited art and properly define the scope of monopoly
of the invention described in the disclosure.
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On December 23, 1977, The Rovac Corporation filed an application for patent
No. 293,849, class 62-127. The inventors are Thomas C. Edwards et al. The
title given to the application is "Control System for Air Conditioner". The
Examiner in charge of the application rejected the claims under Section 36(2) of
the Patent Act and on obviousness. The applicant then requested that the
rejection be reviewed, and that there be a Hearing to consider his arguments.
In reviewing the rejection, the Patent Appeal Board held a Hearing on December
10, 1980, at which the Applicant was represented by W. Parks.
The invention is directed to an air conditioning system for use in automobiles.
Figures 1 and 2 below illustrate the system.
(See figure I)
(See figure II)
Air conditioning system 30 utilizes a compressor-expander in a closed loop with
primary heat exchanger HX1 in an ambient atmosphere and secondary heat exchanger
HX2 in an enclosed space. A source of auxiliary air is injected into the loop
by means of pump 60 to provide varying pressures under thermostatic control 70
providing variation in the heat rate of the system to maintain a set temperature
in the enclosed space.
In the Final Action the Examiner refused the claims for failing to define
patentable subject matter beyond what is shown in the following United States
Patents:
2,715,317 August 16, 1955 C1 62-3 Rhodes
3,904,327 September 9, 1975 C1 418-8 Edwards et al
In his rejection the Examiner argued that claim 1 would be allowable if the
following features are defined:
1) the auxiliary pump
2) the secondary heat exchanger normally operating at atmospheric
pressure
3) the secondary heat exchanger pressure being variable from a
pumped down condition effectively zero to a pressure two to
three times atmospheric to thereby greatly increase the heat
rate of the basic system.
In response to the Final Action the Applicant objected to the stand taken
by the Examiner. He referred to the following paragraph at page 3 of the
disclosure, which reads:
In accordance with the present invention the source of
auxiliary air is provided with injecting means preferably
in the form of a pump for controllable injection of air
from the source into the closed loop, enabling the secondary
heat exchanger to operate at a pressure substantially greater
than atmospheric thereby to increase the heat rate of the
system.
It is believed that applicant is entitled to use the words
"injection means" in the claim. The term is quite apt in view
of the fact that the means is defined as means "for injecting
air". Applicant is not aware of any reason based upon prior art
why applicant should not be entitled to use the term "injection
deans" simply because applicant believes it might be preferable
to use a conventional pump as an injector, does not mean that
applicant should be limited to the use of a conventional pump.
Any injecting means, capable of injecting air under pressure,
may be used to practice the invention.
The issue before the Board is whether or not the application is directed to a
patentable advance in the art.
The patent to Edwards et al teaches a rotary compressor-expander which is
similar to the one used in the present application.
Rhodes teaches a control system for a reversible heat pump or air conditioner.
The system operates with freon in the reversed Rankin cycle. Figure 2 below
illustrates the cooling cycle of that arrangement:
(See figure I)
Refrigeration compressor 10 is connected to heat exchangers 28, 29 and 14, 15.
Four check valves insure unidirectional flow through metering device 49 so that
the capillary restriction of the metering device divides the system into high
and low pressure sides. Restrictor 35 permits refrigerant to slowly return to
the low pressure side of the system and to increase the charge until control
switch 44 opens again.
Claim 1 of the application reads as follows:
1. In an air conditioning system for an enclosed space, the
combination comprising a compressor having an inlet port and
an outlet port, an expander having an inlet port and an outlet
port, the compressor and expander having rotor means including
vanes for positive compression and expansion as the rotor means
is driven, a primary heat exchanger connected between the
compressor outlet port and the expander inlet port, a secondary
heat exchanger connected between the expander outlet port and the
compressor inlet port complete a closed loop having a charge
of air, one of the heat exchangers being thermally coupled to
the enclosed space, a source of auxiliary air, injector means
for injecting air from the source into the closed loop to
increase the pressure in the secondary heat exchanger to sub-
stantially above atmospheric level to increase the heat rate of
the system, and control means for controlling the injector
means thereby to control the pressure existing in the loop.
At the Hearing Mr. Parks argued that Rhodes' refrigeration system differs in a
number of ways from applicant's system. Rhodes does not have a closed loop with
a "charge of air", as defined in claim 1. That system operates with freon in
the reversed Rankin cycle, whereas Applicant's system operates with air in the
reversed Brayton cycle. Rhodes has freon seeping passively into the lower
pressure side, whereas claim 1 defines an injector means for pumping the system
above atmosphere - exactly opposite to Rhodes' restrictor 35. Consequently, the
system is safer to use, responds to a wider variety of conditions and has a
quicker response time.
We note that the expression "injector means" in claim 1 defines the way in which
the result of an element of the combination is accomplished. The means for
performing the act of injecting is recited in a proper combination and covers
the auxiliary pump which is described in the application as performing the
action. No particular injecting element is essential to the combination and we
therefore conclude that the statement of means is proper.
The Applicant argued, in reply to requirements 2 and 3 of the Examiner's action,
that in the prosecution of an application he is entitled to indicate operating
characteristics and advantages of the system without having to put them into the
claim. He stated that operating features and characteristics which are
inherently present in the system defined do not need to be included in the
claim, as they provide unnecessary limitations to the scope of monopoly. Claim
1 defines an "injecting means for injecting air from the source into the closed
loop to increase the pressure in the secondary heat exchanger to substantially
above atmospheric level...." The system, as shown in Figure 2 of the drawings,
operates in this manner. We agree with the Applicant that the expression "the
secondary heat exchanger normally operating at atmospheric pressure" is not
required in the claim. In our view the third requirement is also unnecessary.
In any case zero pressure cannot be obtained in the system when the pressure can
only be increased above atmospheric level. As the compressor-expander of
Edwards et al cannot be substituted for the compressor of Rhodes' refrigeration
system the attack on obviousness must also fail.
The matter of narrow and broad claims was considered in Burton Parsons v
Hewlett-Packard S.C.C. 17 C.P.R. (2d) 97 (1975), p. 106 where it was stated (in
part):
It is stressed in many cases that an inventor is free to make
his claims as narrow as he sees fit in order to protect himself
from the invalidity which will ensue if he makes them too
broad. From a practical point of view, this freedom is really
quite limited because if, in order to guard against possible
invalidity, some area is left open between what is the invention
as disclosed and what is covered by the claims, the patent may
be just as worthless as if it was invalid. Everybody will be
free to use the invention in the unfenced area. It does not
seem to one that inventors are to be looked upon as Shylock
claiming his pound of flesh.
We think that the present case is one where that principle would apply.
Consequently we recommend that the rejection be withdrawn, and that the
application be remanded to the Examiner for further prosecution.
J.F. Hughes
Assistant Chairman
Patent Appeal Board, Canada.
Having reviewed the prosecution of this applicator, I concur with the
recommendations of the Patent Appeal Board. The application is to be returned
to Examiner.
Agent for Applicant
A.E. MacRae & Co.
Box 806 Station B
J.H.A Gari‚py Ottawa, Ont.
Commissioner of Patents K1P 5T4
Dated at Hull, Quebec
this 20th. day of March, 1981