GB465556A - Improvements in or relating to method of and apparatus for coating paper and the like - Google Patents

Abstract

<PICT:0465556/IV/1> <PICT:0465556/IV/2> <PICT:0465556/IV/3> Apparatus for coating a travelling web of paper or the like with liquid, for example colour, comprises a rotating spray roll 15 mounted adjacent to, but not in contact with the web and fed by projecting liquid against its surface at a velocity less than the surface speed of the spray roll but in the same direction as its rotating surface, for example by spray from a transfer roll 10 rotating at a lower speed than and in the opposite direction to the spray roll. A take-up roll 5 rotating in the same direction as but at a lower speed than the transfer roll 10 dips into a reservoir 2 and feeds the transfer roll with spray. The take-up roll 5, Fig. 4, is provided with circumferential grooves 9 and doctors 7. Similar grooves 12 are provided on the transfer roll 10 so that the flanges and grooves intermesh without actual contact. The spray roll 15 has spiral grooves 18 and is provided with guards 19 to confine the spray. A web 20 is drawn from a supply roll 40 around guide rolls 41, 42, beneath a suction box 21 and around guide rolls 43, 44 to a drier (not shown). The bottom portion of the suction box 21 is formed by members 22, Fig. 3, extended inwardly from the sides to leave an opening 23. A plurality of rolls 24 are positioned below members 22 and are rotated at web speed by a pulley 26. A pair of rods 27, Fig. 1, slidably support adjustable deckles 28 the upper edges of which slide on the under side of the members 22 and of which the lower portions provided with projections 29, Fig. 1, extend downwardly between the rolls 24 thus sealing the space at the ends of the rolls 24. Suction is applied to the suction box 21 through a conduit 34. In modifications the spray roll 15 may have a plurality of oppositely directed spiral grooves and an additional spray roll may be mounted behind the main spray roll to catch excess spray and return it to the web. Two opposed coating units may be used to coat simultaneously both sides of the web. Paper webs may be coated immediately after delivery from the paper making machine. The apparatus may also be used for coating previously sized webs with fine powders such as gold, aluminium, or mica.