constituting a slotted arcuate body with a screw spanning the slot to reduce the diameter of a central opening within the body and to which a dryer bolt head is clamped to fix the panel to the end face of the dryer cylinder to reduce heat loss axially of the cylinder application_number US 8123979 A description the present invention has particular application to heatable dryer cylinders for the drying of paper webs and the like and in that regard referring to fig1 there is shown a portion of one such cylinder as indicated generally at 10 the dryer cylinder 10 including a metal cylindrical body 12 and being connected to a central shaft 14 for rotation about the shaft axis through end bells 16 which are coupled to the body 12 by means of a plurality of bolts indicated generally at 18 and which form a circumferentially spaced array on the end bell 16 and facing axially outwardly of the dryer cylinder 10 referring further to fig1 the thermal panel indicated generally at 20 comprises an assembly of two arcuate thermal panel sections or halves as at 22 24 the sections including faces as at 22a 24a which abut each other and when coupled together by way of joint covers 26 form a ringlike assembly which surrounds a projecting hub portion 16a of the end bell 16 the thermal panel 20 thermally blocks a major portion of heat from escaping from the ends of the dryer cylinder 10 either by way of radiation or convection a seal ring 28 is applied to the joined sections 22 24 receives.