Sealing arrangement for an internal tubesheet for tubular heat exchangers comprising, a gasket fitted between a shoulder and a tubesheet, the gasket being made of spiral wound construction but without any metallic rings and without any locating groove in the adjoining components. On the outer side of the tubesheet, a channel box is provided with its inner face resting on a shoulder provided on an outer diameter of the tubesheet while the outer face of the channel box is reduced in diameter and arranged to align with the centerline of the push bolts, the outer face of the channel box resting against and attached to an annular ring and the push bolts being provided in threaded holes that reach up to the outer face of an internal flange. The push bolts, when tightened, load the annular ring, which in turn loads the gasketed joint through the channel box and the tubesheet.