"1.
A closure cap comprising a rigid insert plate having vent holes provided
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therethrough, which vent holes are adapted to be opened and closed by valve members subject to the action of
compression springs, at least one valve member allowing air or gas to pass through at least one vent hole in one
direction and at least one other valve member allowing air or gas to pass through another vent hole in the opposite
direction, the valve members being constituted by a sealing plate supported against annular toroidal supports pressed
out of the insert plate, one such sealing plate being located above the insert plate and a second sealing plate being
located below the insert plate such that when the pressures on opposite sides of the insert plate are not equal, one
sealing plate is removed from its supports and air or gas passes through the thus opened vent hole."
Upon analysis Van Dijkhorst found claim 9 of the 1987 patent to comprise the following integers:
(a) Twoway valve means for use in an arrangement as claimed in any one of the preceding claims,
(b) the valve means comprising a housing,
(c) having a crossplate thereacross,
(d) at least two apertures through the crossplate,
(e) and a pair of oppositely opening oneway valves carried in the crossplate.
As regards claim 1 of the 1989 patent, the learned Commissioner found the following integers:
(a) A valve means for use in sanitary plumbing the valve comprising
(b) a housing having
(c) an inlet connectable to a pipe,
(d) sealing means at the said inlet whereby the inlet can be sealed to the said pipe,
(e) a crossplate across the housing,
(f) a plurality of apertures through the said crossplate and
(g) a plurality of oneway valves respectively controlling fluid flow through the said apertures,
(h) at least one of such valves permitting flow through its associated aperture in one direction only,
(i) and the other said valve permitting flow through its associated aperture in the opposite direction only.
These analyses are accepted by the appellant.
Van Dijkhorst J made a comparison between these claims, thus analysed, and the Blau patent and held that it
was clear that integers (b), (c), (d) and (e) of claim 9 of the 1987 patent and integers (b), (c), (e), (f), (g), (h) and (i)
of claim 1 of the 1989 patent were to be found in the Blau patent. (The judgment does not mention integer (c) in
this context, but this appears to have been an oversight: there does not seem to be any dispute about integer (c).)
This finding was not challenged on appeal. The dispute is thus narrowed down to integer (a) of both patents and
integer (d) of the 1989 patent. I shall deal first with integer (a).
Integer (a) of the 1987 patent speaks of a twoway valve means
"for use in an arrangement as claimed in any one of the preceding claims."
Page 8 of [1996] 1 All SA 1 (A)
Clearly this must be read as referring to use in a plumbing arrangement in a toilet system. Integer (a) of the 1989
patent speaks of a valve means
"... for use in sanitary plumbing ..."
Appellant contends that these uses are integral parts of the invention and that they serve to distinguish the
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1987 and 1989 patents, as claimed, from the Blau patent. The same contention was put forward, and rejected, in
the court a quo, which held that the words expressing these uses informed the reader of the claims what the field of
application of the invention was, but did not constitute essential integers thereof. (See reported judgment, at p
474475.)
I agree. The general approach to be adopted in regard to words in a patent claim indicative of a use or purpose
to which the invention is put was dealt with by this Court in the case of Gentiruco AG v Firestone SA (Pty) Ltd
1972 (1) SA 589 (A). The subjectmatter of the invention in that case was mainly a method for the making of
pneumatic tyres out of synthetic rubber. The opening words of claim 1 of the specification read
"A method of making a rubber compound suitable for a rubber tire ..."
The meaning in this context of the words "suitable for a rubber tire" was a muchdebated issue on appeal to this
Court. The question was whether they imported an integer delineating the kind of rubber compound and, if so, in
what way; or whether it was merely descriptive and consequently of no real significance. This issue of interpretation
was of importance, inter alia, on the question of anticipation. In regard to certain submissions made on behalf of the