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.
