valve to be described steam pressure may be inadequate to overcome the static head necessary to lift the condensate from the lowermost regions because steam and condensate flow will tend to follow the lower pressure paths in the upper regions of the steam condensate flow path as a result pooled condensate in the lower region of the roll will tend to accumulate and insulate the outer wall 11 from the conduction of heat because water has poor heat conductivity as compared to steel the remainder of the cylindrical outer wall of the roll remains preferentially heated to operating temperature the insulated lower portion may bow inwardly as a result of thermal contraction upon re start the distortion may be so severe as to cut or tear the paperboard web being processed the open end of the stub shaft 33 is surrounded by an enclosing end cap 45 the end cap is stationary with respect to shaft rotation and includes a cylindrical outer sleeve 46 which is separated from the roll shaft with a bearing 47 and rotary seal 48 the bottom of the sleeve 46 is provided with a condensate drain hole 50 from which condensate leaving the axial condensate bores 44 in the shaft 28 is returned to the steam boiler system a condensate control valve 51 includes a tubular body 52 having a through steam supply bore 53 one end of the tubular body 52 is supported in the outer wall 55 of the end cap 45 by an annular.