A flush valve diaphragm that includes a body portion and a peripheral sealing portion. The body portion is flexible and has a central passageway. The peripheral portion includes an integral filter, an exit chamber, and a bypass arrangement, such that water flowing through the filter flows through the...http://www.google.de/patents/US6923425?utm_source=gb-gplus-sharePatent US6923425 - Flush valve diaphragm
