Roll for use in calenders and the like

Claim 1

A pressure applying roll for use in calenders and analogous machines to define with a complementary roll a nip for the passage of running paper webs and the like, comprising a hollow flexible rotary cylindrical shell; an elongated carrier extending through and spacedly surrounded by said shell; hydrostatic bearing means interposed between said shell and said carrier and including at least one row of first fluid-operated bearing elements extending longitudinally of said carrier and arranged to apply to said shell a first substantially radial force acting in a first direction, and at least one row of second fluid-operated bearing elements extending longitudinally of said carried and arranged to apply to said shell a second substantially radial force having a component acting in a second direction counter to said first direction; a source of pressurized hydraulic fluid including means for tempering the fluid; means for conveying pressurized fluid from said source to said bearing elements including means for altering the rate of fluid flow to said bearing elements as a function of pressure changes, comprising compensator means operative to distribute said pressure changes among said first and second bearing elements so that the resulting changes of said first force match or closely approximate the resulting changes of said second force; and means for monitoring the temperatures of said shell at a plurality of locations longitudinally of the nip of the rolls and for transmitting to said compensator means first signals denoting the temperatures of the shell at said locations, said compensator means including means for comparing such first signals with second signals denoting the desired temperatures of the shell at said locations and said compensator means being arranged to alter the rate of fluid flow to bearing elements independtly of the nip pressure adjacent those locations where the monitored temperatures deviate from desired temperatures.