Air filter installations

Claim 1

AN AIR FILTER INSTALLATION COMPRISING AT LEAST TWO COMPONENT UNITS, A WALL IN EACH UNIT DEFINING INLET AND OUTLET CHAMBERS IN EACH UNIT, AN APERTURE IN EACH SAID WALL, AN AIR FILTER ELEMENT RELEASABLY MOUNTED IN EACH SAID APERTURE, A BYPASS CONDUIT EXTENDING THROUGH EACH SAID WALL AND FLUIDLY COMMUNICATING THE INLET CHAMBER WITH THE OUTLET CHAMBER OF EACH RESPECTIVE UNIT, A VALVE IN EACH SAID BYPASS CONDUIT OPERATIVELY ASSOCIATED THEREWITH FOR OPENING AND CLOSING ITS ASSOCIATED BYPASS CONDUIT, EACH OF SAID INLET CHAMBERS HAVING AN INLET DUCT OPERATIVELY ASSOCIATED THEREWITH FOR CONDUCTING AIR TO BE FILTERED THEREINTO, A VALVE IN EACH SAID INLET DUCT OPERATIVELY ASSOCIATED THEREWITH FOR OPENING ANDCLOSING THE INLET DUCT WITH WHIH IT IS ASSOCIATED, EACH OF SAID OUTLET CHAMBERS HAVING AN OUTLET DUCT OPERATIVELY ASSOCIATED THEREWITH FOR CONDUCTING FILTERED AIR OUT OF SAID OUTLET CHAMBERS, A VALVE IN EACH SAID OUTLET DUCT OPERATIVELY ASSOCIATED THEREWITH FOR OPENING AND CLOSING THE OUTLET DUCT WITH WHICH IT IS ASSOCIATED, A FURTHER DUCT FLUIDLY COMMUNICATING THE INLET CHAMBERS OF EACH UNIT WITH THE INLET CHAMBER OF EACH OTHER UNIT, VALVE MEANS IN SAID FURTHER DUCT FOR SELECTIVELY OPENING AND CLOSING SAID FURTHER DUCT, AN AIR FILTER POSTING PORT IN EACH INLET CHAMBER AND OPERATIVELY ASSOCIATED THEREWITH FOR POSTING A FILTER INTO AND OUT OF SAID INLET CHAMBER WITH WHICH THE POSTING PORT IS ASSOCIATED, AND EACH INLET AND EACH OUTLET CHAMBER HAVING AT LEAST ONE GLOVE PORT OPERATIVELY ASSOCIATED THEREWITH FOR CARRYING OUT MANUAL OPERATIONS WITHIN THE CHAMBER WITH WHICH A RESPECTIVE ONE OF SAID GLOBE PORTS IS ASSOCIATED.