GB667117A - Improvements in or relating to methods of heat-treating travelling webs - Google Patents

Abstract

667,117. Feeding and drying webs. SELAS CORPORATION OF AMERICA. April 26, 1949 [April 27, 1948], No. 11064/49. Classes 100 (i) and 120 (ii). [Also in Groups XI, XII, XXVIII, and XXIX] A method of moving a travelling web into and out of an oven comprises passing the web through a first loop of variable length, said loop extending at its maximum length into said oven, and, when it is desired to move the web out of the oven, decreasing the length of said loop while increasing by the same amount the length of a second loop outside the oven. A continuously moving paper web W delivered from a printing-press is fed in a loop around a roller 4 and within an oven 11 to dry ink on the web before a second impression. The web is fed in a second loop around a roller 5 and also around water-cooled rollers 7 and 8 and then to a second press. The rollers 4 and 5 are mounted on a movable carriage 6 comprising side plates 12 and 13, Fig. 2, a shaft 22 carrying pinions 23 at each end meshing with a vertical rack 25 and guide rollers 14 running in vertical tracks 15. The carriage 6 is moved into and out of the oven 11 by piston rods 36 and 37 attached to the side plates 12 and 13. Hydraulic or pneumatic cylinders 34 and 35 are mounted on the frame of the device and are supplied with fluid at either end by pipes 39 and 41 through a valve 57, such that when a piston rod 59 is in an upper position, fluid is supplied to the top of the cylinders through the pipes 39 to cause the carriage 6 to move down and when the rod 59 is in a lower position, fluid is supplied to the bottom of the cylinders through the pipes 41 to cause the carriage to move up and withdraw the web from the oven. The rod 59 is held in its upper position against the action of a spring 63 by a solenoid 65 which is energised when the printing-press is put into operation. The oven 11 comprises two panels 42 and 43 separated by slots 49 which accommodate the shaft 31 of the roller 4 and is provided with burners supplied with gas through pipes 46 connected .to a manifold 47, each pipe 46 being provided with a valve 48 permitting individual adjustment of the burners. The manifold 47 is supplied with gas through a valve 54 which is operated by a solenoid energised to open the valve when the press is started. A by-pass 55 having a manually-operated valve 56 supplies gas to the burners to maintain the oven at a desired temperature when the valve 54 is shut, thus ensuring that the oven will be sufficiently warm to dry the web as soon as the web is moved into the oven. In a modification the rollers 4 and 5 are mounted on journals carried on screwed rods rotated by a motor to move the web into and out of the oven. The loop formed outside the oven to take up the slack when the loop in the oven is shortened may be formed in a horizontal direction. In a further embodiment, the loop formed outside the oven may be controlled by a roller mounted in journals slidable along shafts and under the influence of a constant force e.g. a cable attached to a weight and passing over a pulley at the end of the shafts. Specification 496,146, [Group XI], is referred to.