GB741371A - An improved method of coating long strips or webs of substantially nonabsorbent material with a liquid simultaneously on both sides - Google Patents

Abstract

741,371. Coating webs. MEULEN, L. VAN DER. Dec. 5,1952 [Dec. 8, 1951], No. 30980/52. Class 140. A method of coating long strips or webs of substantially non-absorbent material simultaneously on both sides with a liquid comprises passing the material in a downward diiection through the coating liquid present in substantial amount in a container having rigid side walls and past the edges of a slit-like outlet aperture in the bottom of the container, in such a way that the longitudinal edges of the slitlike aperture adapt themselves constantly yieldingly to the variations in thickness of the passing material in such a manner that the coating liquid will only cling or adhere to the material after emerging from the aperture. As shown in Figs. 3 and 4, the container for the coating liquid with the slit-like outlet aperture is formed by a pair of rolls 23, 24 preferably made from an elastic material or coated with an elastic material such as gelatin, placed parallel to each other in a horizontal plane, at least one roll 23 being continuously pressed towards the other roll and against the passing material 21 from the supply roll 22 by springs 29, 30 and sliding bearings 27, 28, both rolls 23, 24 being connected by a chain (not shown) passing over the sprockets 31, 32 by which both rolls 23, 24 will have the same peripheral speed. The coating liquid is continuously supplied from supply lines 47, 48 having spaced discharge openings at both sides of the material 21, between this material and the rolls so that the liquid is always in contact with the material over its full breadth, the superfluous liquid running into vessels 49, 50 from which it may be pumped back to the supply lines 47, 48. The treated material 21<SP>1</SP> after leaving the rolls 23, 24 is dried and again conveyed upwards by conveying rolls 33a, 33b and 33c so that the apparatus may be controlled from the same floor in which the apparatus is placed and finally the coated material is wound on the roll 34. An electromotor 35 drives the roll 23 through a reduction gear (not shown) and also the driving roll 40 and the roll 34 by rope pulleys 36, 37 mounted on the same shaft through the rope pulleys 38, 39. When the coated material is ruptured between the rolls 23, 24 and the driving roll 40 and is not therefore tightly stretched, the feeding current of the electromotor is interrupted by co-operation of the trailing roll 42, the lever system 43 being rotatable around the hinge shaft 44, the pulling spring 46 and the interrupter pin 45 and the apparatus is automatically stopped. The material, which may not be completely dried from a preceding coating, may be subjected to two or more successive coating treatments or to a subsequent printing or impressing treatment by passing it through multiple apparatus as described placed below each other.