Green Patent Blog

Earlier this month I attended the CleanTech 2008 Summit and Exhibition in Israel.  The trade show focused on renewable energy, conservation technology, and, not surprisingly given the country’s climate and neighborhood, water technologies.

One company that stood out was Hydropath Holdings Ltd. (Hydropath), a British water treatment firm who was exhibiting its technology through its Israeli marketer, Waterpath (itself a division of Pazgas, an Israeli gas company).  Hydropath’s technology cleans limescale in commercial, industrial and residential water systems without the use of chemicals by a device that attaches to pipes and generates electric fields in the water flow.  According to Hydropath’s web site, 1 mm of limescale deposition can reduce the efficiency of a residential boiler by 10%.

Limescale deposits occur when positively and negatively charged ions such as calcium carbonate and bicarbonate exceed a maximum concentration and crystalize out of solution onto pipe surfaces.  Crystallization can be either homogeneous (the initial “seed” crystals are formed by oppositely charged ions of the dissolved substance) or heterogeneous (the initial seed crystals are formed by ions on an alien substance such as a pipe surface).  This latter type of crystallization leads to scale deposition on pipes.  Homogeneuously-formed crystals, on the other hand, are carried through the pipe without impeding water flow.

Hydropath owns several patents and applications in the U.S. and abroad, including U.S. Patent No. 5,667,677 (677 patent) and two applications, International Pub. Nos. WO 2007/045824 (’824 application) and WO 2008/017849 (’849 application).  As described in the ‘849 application, the electric field produced by Hydropath’s device orients the molecules so all of the positively charged ions are aligned and traveling in one direction, and all the negatively charged ions are aligned and traveling in the opposite direction.  This increases the odds of collision between particles of opposite charge, and leads to increased growth of the benign homogeneous crystal clusters.  It also decreases the saturation level of the solution, so existing limescale deposits can re-enter solution and flow out.

The ‘824 application discloses using the electric field to provide a more energy efficient desalination process.  The electric current causes water to re-orient into a thin layer of molecules with positive poles on one side and the negative poles on the other side.  This “hydration” layer excludes other molecules and contains substantially pure water, which can be extracted using less energy than other desalination methods.

Hydropath’s patented technology has many applications, including boilers, heat exchangers, swimming pools and fuel pipes, and according to the company’s web site, can be used to combat bacteria, algae and other substances in addition to limescale.

Earlier this month, Sprite Industries sued Culligan in the Central District of California for infringement of a patent on a shower filtration device.  The patent covers a combination showerhead and water filter held together in a single housing.  The housing has top and bottom mating halves that are either screwed together or threaded together, a water filter assembly secured in the housing and a baffle to direct the water flow through the filter.  The patented device reduces potential head bumps to the bather because it takes up less shower space than prior art devices, which typically required that a separate shower head be attached to a filter outlet.  The accused device is Culligan’s wall-mount filtered showerhead.  

Section 120 of the patent laws allows a patent applicant to file “continuation” applications from a previously filed “parent” application.  Each continuation in a patent “family” is entitled to the same filing date as the original application as long as the continuations specifically reference the prior applications in the family and disclose all of the same material.  Establishing a continuous chain of priority to an early filing date can be critical to preserving the “novelty” of an invention because, if the chain is broken, intervening prior art can render a “child” or “grandchild” patent invalid as “anticipated” (i.e., not novel).  A broken chain can also transform one’s own “grandparent” or parent application into prior art that could invalidate subsequent related patents or applications.

Through continuation practice, Zenon obtained a family of patents directed to water treatment and filtration systems.  Zenon sued U.S. Filter, alleging infringement of its grandchild patent.  The invention of the grandchild patent consists of two critical elements - a vertical skein and a gas distribution system.  The skein includes porous or semipermeable fibers potted in a solid resin and a collection means to collect permeate from the ends of the fibers.  The skein is submerged in water, the water flows into the fiber array, and the permeate is collected from the ends of the fibers.  For the process to work effectively, the surface of the fibers must be kept free of particulate matter to ensure the free flow of permeate over an extended period of time.  The gas distribution system generates a cleansing gas, and the resulting gas bubbles keep the fibers clean by scrubbing them and causing them to scrub against each other.

Both the grandparent and the grandchild patents disclosed the skein and the same type of gas distribution system.  However, the intervening child patent disclosed a different gas distribution system and incorporated by reference “relevant disclosures” only relating to the skein.  Because the child did not actually disclose the original gas distribution system and failed to incorporate by reference either the entire grandparent application or the original gas distribution system, the U.S. Court of Appeals for the Federal Circuit held that Zenon had lost its continuous chain of priority to the grandparent application.  The chain was broken by the deficient disclosure of the intervening child patent, and the grandparent patent was transformed into prior art that invalidated the grandchild.

Zenon’s “continuing” problems could have been avoided by doing one of two things: simply copying and pasting the entire disclosure of the grandparent application into the intervening child application, or expressly incorporating by reference the entire grandparent application in the child application.