A recent South African case

Judge Basson, sitting as the Commissioner of Patents, recently handed down judgment in the case of Hans Sasserath GMBH & Co. KG and Halograph (Pty) Ltd v Advanced Valves CC.

The case deals with the alleged infringement of a South African patent for a "vent valve", commonly referred to as an "AV vent valve" or a "vacuum breaker". The defendant denied that its product falls within the scope of the patent, but it did not attack the validity of the patent.

The outcome

The judge held that the defendant's AV valve does fall within the scope of the claims of the patent. The Commissioner issued an interdict and ordered an enquiry into damages, or alternatively a reasonable royalty, and payment of legal costs.

We could end this article right here. However, we're not going to because the judgment contains a very useful refresher on the law relating to patent infringement in South Africa.


Section 45 of the South African Patents Act,1978 grants the patentee the right to exclude others from:

  • making;
  • using;
  • exercising;
  • disposing or offering to dispose of; and
  • importing

the invention, meaning that the patentee enjoys the whole profit and advantage accruing from the invention.

To determine whether there has been an infringement, the court must first determine exactly what was invented and what the scope of the patent is.

Case law

Judge Basson cited a great deal of case law, starting with the case where everything starts:


In South Africa's best-known patent case, Gentiruco v Firestone, the court said that "our very first task is to ascertain the nature of the invention as claimed and its precise scope". As such, "the specification, and especially the claims have to be construed; it is, after all, the instrument on which the letters patent were applied for and granted and it must therefore necessarily govern those issue".

The pith and the marrow, good sense: stay out of this, lawyers

In theAktiebolaget Hassle and another v Triomed (Pty) Ltd case, the court said: "In making the comparison the law looks at the essence of what is contained in the claim and will not allow what is described as the 'pith and marrow' of the protected invention to be pirated. The evaluation of what is the substance or essence of an invention is a matter for the ''good sense'' of the judicial tribunal seized with the enquiry."

The court described the patent specification as "a unilateral statement by the patentee to those 'skilled in the art' of what he/she 'claims to be essential'. It is something that should be given a 'purposive construction rather than a purely literal one derived from applying to it the kind of meticulous verbal analysis in which lawyers are too often by their training tempted to indulge."

Don't peer too closely

A similar sentiment was expressed in the case of Multotac Manufacturing (Pty) Ltd v Screenex Wire Weaving Manufacturers (Pty) Ltd Here, the court said that "it is true that it is in the claims that a patentee stakes out and defines his monopoly and that the claims must be looked at in order to determine whether an infringement has taken place. But by peering too closely at the language of a claim the court may overlook an infringement which takes the substance of the invention."

Monsanto - a useful synopsis

The Monsanto Co v MDB Animal Health (Pty) Ltd case sums it up nicely.

  • a specification should be construed like any other document;
  • the object is not to ascertain what the patentee had in mind, but rather what the language used in the specification means;
  • the words must be read grammatically and in their ordinary sense;
  • technical words must be given the meaning as ordinarily understood in the particular science; and
  • where it appears that the word is not used in its ordinary sense but with a special connotation it must be given that meaning.

In conclusion

We'll end with these refreshingly plain words that were delivered by a UK judge, and were quoted in the present judgment (it's unfortunately not clear to me what the citation is). It says it rather well:

"It is seldom that the infringer does the thing, the whole thing, and nothing but the thing claimed by the specification. He always varies, adds, omits, and the only protection the patentee has in such a case lies, as has often been pointed out by every court, from the House of Lords downwards, is the good sense of the tribunal which has to decide whether the substance of the invention has been pirated."

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