Bromine Compounds Ltd v Buckman Laboratories (Pty) Ltd In re: South African Patent No. 92/4018

• Jurisdiction: South Africa
• Judge: Southwood J
• Judgment Date: 12 September 2006
• Citation: 2006 JDR 0975 (CP)
• Docket Number: 92/4018
• Court: Court of the Commissioner of Patents

Southwood J:

[1]

The plaintiff, the patentee of South African Patent No 92/4018 entitled 'Process and Compositions for the Disinfection of Waters' ('the patent') seeks an interdict and ancillary relief (enquiry into damages) against the defendant on the grounds of the defendant's infringement of claims 1, 2, 6, 10, 13, 14, 15, 19, 23 and 26 of the patent. The plaintiff alleges that the defendant has used and exercised and is still using and exercising a process for disinfecting water ('the process') at a number

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of paper mill plants thereby infringing the aforementioned claims of the patent.

[2]

The defendant admits that the plaintiff is the patentee of the patent, that the defendant used and exercised and is still using and exercising the process at a number of paper mill plants and that, if the patent is valid, the defendant has infringed the aforementioned claims of the patent. The defendant denies that the patent is valid and contends that it is liable to be revoked on the grounds that the invention was not patentable under section 25 of the Patents Act 57 of 1978 ('the Act') in that (a) it was not new and (b) it did not involve an inventive step. Accordingly the defendant contends that it was not necessary to obtain the authority of the plaintiff to use the process and that its use of the process was not an infringement of the patent.

[3]

In its counterclaim for the revocation of the patent the defendant alleges (a) that the invention was not new in that it formed part of the state of the art immediately before the priority date and (b) that the invention did not involve an inventive step in that it would have been obvious to a person skilled in the art having regard to matter which formed part of the state of the art immediately before the priority date. On the issue of novelty the defendant initially relied on 13 allegedly anticipatory articles and patents. On the issue of obviousness the defendant initially relied on the 13 allegedly anticipatory publications and a further 9 articles and patents. In its plea to the counterclaim the

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plaintiff admits that all but one of the publications formed part of the state of the art. The publication not admitted is 'Disinfection, Sterilization, and Preservation' by Seymour S. Block and is dated 2001, i.e. after the patent's priority date of 3 June 1991. The onus of proving that the patent is invalid on either ground rests on the defendant - see Gentiruco AG v Firestone SA (Pty) Ltd 1972 (1) SA 589 (A) at 629E - F (1971 BP 58 (A) at 108B) ('the Gentiruco case'); Roman Roller CC and another v Speedmark Holdings (Pty) Ltd 1996 (1) SA 405 (A) at 412F-G (1995 BIP 199 (A) at 208E-F) ('the Roman Roller case'); Coflexip SA v Schlumberger Logelco Incorporated 2001 BIP 1 (CP) at 9H-10A.

[4]

In its plea the defendant admits that (1) the plaintiff is the registered proprietor of the patent and that a copy of the patent is annexed to the plaintiff's particulars of claim as "A"; (2) the defendant, without the authority of the plaintiff , has used and/or exercised and is still using and/or exercising the process at the following paper mill plants: Sappi Enstra; Sappa Adamas; Sappi Stanger; Sappi Ngodwana; Mondi Meerbank and Mondi Richards Bay; (3) the process is a process for killing microorganisms and controlling biofouling in high chlorine demand circulating waters of paper industry systems (claims 1 and 14); (4) the process comprises the mixing of two components, one of which is an oxidant in the form of a chlorine precursor in solution (claims 1 and 14); (5) the other component in the process is an ammonium salt in solution (claims 1 and 14); (6) the mixing of the components in the

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use and/or exercising of the process forms a biociodal mixture (claims 1 and 14); (7) the process further includes adding the biocidal mixture immediately to the high chlorine demand aqueous system to be treated (claims 1 and 14); (8) the chlorine precursor used in the process is sodium hypochlorite (claims 2 and 15); (9) in using and/or exercising the process the oxidant is added to a solution of the ammonium salt ( claims 6 and 19); (10) in using and/or exercising the process, the mole ratio N/CI in the mixture is at least 1:1 and the final concentration in the mixture is 0.1-1 % as chlorine ( claims 10 and 23) and (11) the pH of the biocidal mixture used and/or exercised in the process is controlled in the range 8.0 to 12.5 (claims 13 and 26).

[5]

The defendant therefore admits that the features of claims 1, 2, 6, 10, 13, 14, 15, 19, 23 and 26 of the patent are present in the process it is using and confirmed this pursuant to a question at the pre-trial conference. Consequently the issue to be decided is whether the patent must be revoked on the grounds that the invention was not new and that it did not involve an inventive step. Accordingly the plaintiff closed its case on its claim in convention without tendering evidence. Then, after the defendant had tendered the evidence of two expert witnesses, professors Cloete and Pretorius, and a factual witness, Mr. Conyngham, the plaintiff, without calling a witness, closed its case on the claim in reconvention. The issues raised by the claim in reconvention must therefore be decided on the publications which are

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common cause on the pleadings, the publications proved in evidence and the defendant's oral evidence.

[6]

According to the patent specification the purposes of the invention are:

(1)

to provide a process and compositions for killing micro-organisms and inhibiting biofouling in waters, especially in cooling waters and aqueous systems having high chlorine demand waters, and more especially in cooling waters and aqueous systems having a high chlorine demand;

(2)

to provide such a process and compositions that have a high biocidal effect and a high initial rate of kill in high chlorine demand waters;

(3)

to provide such a process and compositions the biocidal effect and the properties of which are constant and predetermined.

The summary of the invention states that the process according to the invention comprises mixing two components, one of which is an oxidant which is an active chlorine donor, preferably sodium hypochlorite, and the other, an ammonium salt, preferably chosen among halides, sulphates and nitrates, and adding the biocidal concentrate immediately to the aqueous system to be treated. The

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frequency, duration and concentration should be determined in each individual case so as to be sufficient to control biofouling.

[7]

Claim 1 of the patent reads as follows -

'A process for killing microorganisms and controlling biofouling in high chlorine demand circulating waters, which comprises mixing two components, one of which is an oxidant in the form of a chlorine precursor in solution and the other an ammonium salt in solution thereby forming a biocidal mixture and adding the biocidal mixture immediately to the high chlorine demand aqueous system to be treated.'

Claim 14 merely limits the claim to 'high chlorine demand circulating waters of paper industry systems' but is otherwise identical to claim 1. Claims 2-13 are dependent on claim 1 and claims 15-26 are dependent on claim 14.

[8]

It is common cause that the integers of the claims are as follows -

(1)

Claim 1 (14)

(a)

a process for killing microorganisms and controlling biofouling in high chlorine demand circulating waters (of paper industry systems);

(b)

which comprises mixing two components;

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(c)

one of which is an oxidant in the form of a chlorine precursor in solution;

(d)

and the other an ammonium salt in solution;

(e)

thereby forming a biocidal mixture;

(f)

and adding the biocidal mixture immediately to the high chlorine demand aqueous system to be treated.

(2)

Claim 2 (15)

Claim 2 (15) is for a process according to claim 1 (14) wherein - the chlorine precursor is sodium hypochlorite.

(3)

Claim 6 (19)

Claim 6 (19) is for a process according to claim 1 (14) wherein - the oxidant is added to a solution of the ammonium salt.

(4)

Claim 10 (23)

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Claim 10 (23) is for a process according to claim 1 (14) wherein-

(i)

the mole ratio N/C L in the mixture is at least 1:1; and

(ii)

the final concentration in the mixture is 0.1 to 1 % as chlorine.

(5)

Claim 13 (26)

Claim 13 (26) is for a process according to claim 1 (14) wherein -

the pH of the biocidal mixture is controlled in the range 8.0-12.5.

[9]

Since the construction of the patent and the other publications (which include articles and other patents) relied upon by the defendant is crucial to the outcome of this action and this may be affected by the expert evidence it will be convenient to consider at this stage the rules pertaining to the construction of a patent and the publications forming part of the prior art and the admissibility of expert evidence. The defendant led a great deal of evidence which it conceded is probably

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not admissible as it dealt with the questions of anticipation and whether the invention involves an inventive step.

[10]

The principles governing the construction of a patent were formulated in the Gentiruco case at 613-618 (BP at 85-93) and may be summarised as follows:

(i)

The rule of interpretation is to ascertain, not what the inventor or the patentee may have had in mind, but what the language used in the specification means; i.e. what his intention was as conveyed by the specification, properly construed, since he is presumed to have intended what his language means (614B-C: 86G-87A);

(ii)

To ascertain that meaning the words used must be read grammatically and in their ordinary...