Patent GB-1420547-A (GB)
Title: Drying oven for printed sheets
IPC: F26B25/00
Filed: 1974-05-30
Abstract: 1420547 Drying ARGON SERVICE Ltd 30 May 1974 23989/74 Heading F4G A vertical oven for drying printed sheets comprises a single control device for ascending and descending movements of conveyers carrying the printed sheets in a vertical direction within the oven and movement of conveyers in a horizontal direction for transferring printed sheets from one vertical conveyer to the other so as to ensure synchronization of the operation of the conveyers, the control device comprises a driving system comprising two driving cams which during a first portion of a rotation thereof transmit motion to the transfer conveyers and during a second portion of the rotation transmit motion to the ascending and descending conveyers and means for stopping the motions of the transfer conveyers and the ascending and descending conveyers during the remainder of the complete rotation of the driving cams. The oven comprises a box, upright and cover members 2 to 5, a heating chamber 9 and a cooling chamber 10. Each chamber has a pair of chain conveyers 11, 11<SP>1</SP> respectively carrying spaced carriers 14 for supporting slotted frames 15 for the sheets to be dried. The chains aresupported by pairs of shafts 12, 12<SP>1</SP>, 13, and 13<SP>1</SP>. The frames and sheets thereon are transferred from the top of the conveyer 11 to the top of the conveyer 11<SP>1</SP> by a conveyer 16 comprising endless chains supported by shafts 19, 20. Shafts 19<SP>1</SP>, 20<SP>1</SP> support an endless chain conveyer 17 for transferring the frames from the bottom of one conveyer to the other. Brackets 16<SP>1</SP> on the conveyer 16 and carriers 14<SP>1</SP> on the conveyer 17 engage the frames to effect the transference. The frames are supplied to the chamber 9 by a wire conveyer 6 and the sheets are discharged on to a belt conveyer 8, a comb 224 prevents the sheets transferring to the chamber 9 by cutting out the drive if it is pivoted by a sheet. The conveyers are driven by an electric motor driving a shaft 23 mounted on the cover 5. The shaft 23 drives a screw 23 which drives a toothed wheel 24 on the hub 24<SP>1</SP> of which is keyed the cams 25, 27 engageable with respective cams 26, 28. For 240 degree rotation of the cam 27, the cam 28 rotates 360 degrees and drives the transfer conveyers 16, 17 by a shaft driving toothed wheels 31, chains 32 and sprocket 33 on the shaft 19 which is connected by chain 211 with the shaft 19<SP>1</SP>. The cam 27 is inoperative for the next 90 degrees and the conveyers 11, 11<SP>1</SP> are then driven in opposite directions by cams 25, 26 through a shaft 29 and gearing. The drive is then stopped for the remaining 30 degrees of rotation of the cams 25, 27 either manually by a push-button or by a microswitch operated by a sheet as it is fed on to one of the frames. A fan 101, Fig. 15 (not shown) withdraws air from -the chambers 9, 10 to a heater and conveys air through pipes in the oven uprights and through a perforated panel extending the length of the conveyer 11. Two blowers supply atmospheric air to a perforated wall to supply cold air to the descending sheets and to an upper horizontal distributer which air also retains the sheets in position during transfer. A suction fan 114, Fig. 16 (not shown) removes solvent vapours through ducts from the chamber 9.