Plate filter and method of manufacture

Claim 1

IN A FILTER UNIT OF THE TYPE DECRIBED, THE COMBINATION OF AN UPRIGHT TUBULAR SUPPORT PROVIDED WITH AT LEAST ONE LATERAL FILTRATE ENTRANCE; A BOTTOM PAN OF SHEET MATERIAL HAVING AN OPENING THROUGH WHICH SAID SUPPORT EXTENDS, SAID PAN HAVING AN OUTER ANNULAR FLANGE EXTENDING AT LEAST GENERALLY PARALLEL TO THE LONGITUDINAL AXIS OF SAID SUPPORT; AN ANNULAR MEMBER EMBRACING SAID FLANGE AND SECURED THERETO, SAID ANNULAR MEMBER AND SAID FLANGE COOPERATING TO DEFINE AN UPWARDLY OPENING ANNULAR GROOVE; A FILTER ELEMENT HAVING AN OPENING THROUGH WHICH SAID SUPPORT EXTENDS, SAID FILTER ELEMENT EXTENDING OUTWARDLY TO SAID GROOVE AND CLOSING THE TOP OF SAID PAN; AND AN ANNULAR RETAINING RING REMOVABLY RETAINED IN SAID GROOVE AND OPERATIVELY ASSOCIATED WITH SAID FILTER ELEMENT TO PACK THE SAME IN PLACE, SAID PAN BEING SEALED TO SAID SUPPORT AND SAID FILTRATE ENTRANCE BEING DISPOSED BETWEEN SAID PAN AND SAID FILTER ELEMENT.

Claim 3

THE METHOD FOR FABRICATING A FILTER UNIT OF THE TYPE DESCRIBED COMPRISING PROVIDING A TUBULAR SUPPORT MEMBER HAVING AT LEAST ONE LATERNAL FILTRATE-ADMITTING PORT;: FORMING FROM A SINGLE METAL SHEET A PAN HAVING AN AT LEAST GENERALLY FRUSTO-CONICAL BODY, A DEPENDENT INNER CYLINDRICAL FLANGE OF SMALLER DIAMETER THAN THE OUTER DIAMETER OF THE SUPPORT MEMBER, AND AN OUTER DEPENDENT ANNULAR FLANGE;

Claim 4

THE METHOD FOR FABRICATING A FILTER UNIT OF THE TYPE DESCRIBED COMPRISING PROVIDING A TUBULAR SUPPORT MEMBER HAVING AT LEAST ONE LATERNAL FILTRATE-ADMITTING PORT;: FORMING FROM A SINGLE METAL SHEET A PAN HAVING AN AT LEAST GENERALLY FRUSTO-CONICAL BODY, A DEPENDENT INNER CYLINDRICAL FLANGE OF SMALLER DIAMETER THAN THE OUTER DIAMETER OF THE SUPPORT MEMBER, AND AN OUTER DEPENDENT ANNULAR FLANGE;