Background
DLP Limited sued Coram UK Holding Limited for allegedly infringing UK Patent No GB 2,446,666, titled “an electric shower-waste pump and control unit.” The patent addresses the risk that water leaking from a shower-waste pump may contact associated electronic control circuitry. It claims a unit containing a pump in a first chamber and electronic controls in a separately sealed second chamber, within a housing closed by a removable, non-watertight cover that permits drainage.
DLP alleged that Coram’s Premium Pump and Bluetooth Pump infringed claim 1 as granted and certain proposed amended claims. Coram denied infringement and counterclaimed that the patent was obvious over the Grumbach and Gontar patent applications and a known commercial product called Quantum. Coram abandoned its lack-of-novelty challenge during trial. DLP proposed amendments to address the invalidity case, which Coram opposed as adding matter.
The Court’s Holding
The court held that neither Coram product infringed. Properly construed, the patented “unit” had to be a single, complete or self-contained shower-waste pump and control unit. Its housing had to surround and protect the claimed chambers, while its removable housing cover had to connect directly with and close the housing, as well as provide access to the unit’s internal components. Coram’s flat backplate was not such a housing cover: it remained fixed to the wall and did not perform the claimed access function. For the Premium Pump, the separate outer cover did not touch the backplate, while the Bluetooth Pump’s clipping arrangement did not cure the backplate’s failure to qualify as the claimed cover.
The court also rejected Coram’s obviousness counterclaim. Grumbach did not disclose the claimed self-contained unit and would not lead the skilled person to the patented arrangement without hindsight. Gontar’s relevant features added nothing to the common general knowledge and supplied no reason to create the claimed housing arrangement. Modifying Quantum as Coram proposed would require the skilled person to add a second watertight enclosure for electronics and then make Quantum’s original watertight housing non-watertight—steps the court considered illogical absent hindsight. The court therefore dismissed both DLP’s infringement claim and Coram’s invalidity counterclaim. Although unnecessary to the result, it stated that it would have allowed DLP’s proposed amendments.
Key Takeaways
- Claim language describing a “unit,” “housing,” and removable “housing cover” required a self-contained arrangement in which the cover directly connected with and closed the housing.
- Coram’s wall-mounted backplate was not the claimed removable housing cover, so both accused pumps fell outside claim 1 and its dependent claims.
- The patent survived all three obviousness attacks because the prior art did not lead the skilled person to the claimed arrangement without impermissible hindsight.
Why It Matters
The decision illustrates how ordinary-language structural terms can determine infringement even where an accused product performs a broadly similar function. Purposive construction did not permit the court to disregard the distinct roles assigned by the claim to the housing and its removable cover.
It also underscores the danger of hindsight in obviousness challenges to relatively simple inventions. Showing that individual components were known was insufficient where the prior art supplied no technically logical route to the claimed combination.