Abstract: A fitting device for a tubular column having an exterior flange at one of its ends is disclosed. The device includes a fitting composed of (i) a piston for insertion into the end of the column adjacent the flange, (ii) an enlarged-diameter member having a contact surface for contacting the flanged end of the column when the piston is fully inserted into the column, and (iii) a circumferential seal encircling the piston for providing a fluid-tight seal between the piston and interior end region of the column, when the piston is inserted into the column. A clamp in the device is received on the column by sliding from the end of the column opposite said flange, for engaging the column flange and the fitting's enlarged-diameter member, to secure the fitting to the column flange, with the piston inserted into the tubular column, thus to maintain said seal when fluid is forced through the fitting by application of pressure to fluid within the column.