Spark arrestor

Claim 1

A SPARK ARRESTOR COMPRISING A LOWER HORIZONTAL FRAME MEMBER FORMED OF A SUBSTANTIALLY CONTINUOUS LENGTH OF STRAP-LIKE MATERIAL, SAID LOWER FRAME MEMBER HAVING ITS WIDTH VERTICALLY DISPOSED AND ADAPTED TO ENCOMPASS A FLUE ELEMENT, MEANS INCLUDING A SCREW THREADED ACTUATOR MOUNTED ON SAID LOWER FRAME MEMBER FOR RELEASABLY CLAMPING SAID LOWER FRAME MEMBER TO SAID FLUE ELEMENT, SCREEN SUPPORTING ELEMENTS EXTENDING INWARDLY FROM THE INNER WALL OF SAID LOWER FRAME MEMBER, A TUBULAR SCREEN CONSTITUTED BY A SHEET OF SCREENING FOLDED OVER ON ITSELF IN OVERLAPPING ENGAGEMENT HAVING THE LOWER EDGE THEREOF TELESCOPICALLY RECEIVED WITHIN SAID LOWER FRAME MEMBER AND SUPPORTED ON SAID ELEMENTS, SAID SCREEN BEING SUBSTANTIALLY CONTINUOUS AND EXTENDING UPWARDLY FROM THE UPPER EDGE OF SAID LOWER FRAME MEMBER WITH THE INNER WALL OF THE SCREEN DEFINING AN UNOBSTRUCTED CHAMBER COEXTENSIVE WITH SAID LOWER FRAME MEMBER, SAID LOWER FRAME MEMBER CONSTITUTING MEANS FOR DETERMINING THE AMOUNT OF OVERLAP OF AND THE PERIPHERAL SHAPE OF THE LOWER EDGE PORTION OF SAID TUBULAR SCREEN, A HORIZONTALLY DISPOSED SUBSTANTIALLY PLANAR COVER SCREEN OVERLYING AND CLOSING THE UPPER END OF SAID TUBULAR SCREEN, MEANS SECURING SAID COVER SCREEN TO, DETERMINING THE AMOUNT OF OVERLAP OF AND DETERMINING THE PERIPHERAL SHAPE OF THE UPPER EDGE PORTION OF SAID TUBULAR SCREEN INCLUDING AN ANNULAR STRAP TELESCOPICALLY RECEIVING THE UPPER EDGE OF SAID TUBULAR SCREEN WITHIN SAID STRAP AND HAVING INWARDLY PROJECTING FLANGE MEANS ENGAGING THE UPPER EDGE OF SAID TUBULAR SCREEN FOR MAINTAINING SAID COVER SCREEN IN POSITION OVER SAID TUBULAR SCREEN.