Anti-cavitation structure for sink drains and the like

Claim 1

AN ANTI-CAVITATION CHAMBER FOR FASTENING TO A CONDUIT BETWEEN A LIQUID RESERVOIR AND A PUMP WHEREIN THE CONDUIT HAS BEEN PROVIDED WITH A RADIAL UPPER GAP THERETHROUGH AND A LOWER RADIAL DRAIN OPENING, THE COMBINATION COMPRISING: (A) A PAIR OF FLANGED SHELLS DEFINING, WHEN JOINED, A CHAMBER CONCENTRIC ABOUT A CONDUIT AND HAVING ONE UPPER RADIAL OPENING TO THE ATMOSPHERE THEREIN AT AN ELEVATION CORRESPONDING TO THE LOCATION OF AN UPPER GAP IN SAID CONDUIT AND HAVING A SECOND LOWER RADIAL OPENING THERETHROUGH AT AN ELEVATION CORRESPONDING TO THE LOCATION OF A LOWER RADIAL OPENING THROUGH SAID CONDUIT AND THROUGH WHICH FLOW FROM SAID CHAMBER IS RECOMMUNICATED TO SAID CONDUIT; (B) A VENT TO ATMOSPHERE IN SAID UPPER RADIAL OPENING AND IN FLOW COMMUNICATION WITH SAID CHAMBER; (C) A PRESSURE SENSITIVE SWITCH CLOSED WHEN PRESSURE WITHIN SAID CHAMBER EXCEEDS ATMOSPHERIC PRESSURE IN SAID LOWER RADIAL OPENING OPERABLY CONNECTED TO SAID PUMP; AND (D) SEAL MEANS SECURING SAID CHAMBER TO SAID CONDUIT ABOVE AND BELOW SAID OPENING AND CLOSING SAID CHAMBER IN AIR AND WATER TIGHT RELATION.