GB1099941A - Device for coating chips with glue - Google Patents

Abstract

1,099,941. Coating apparatus. BAHRE METALLWERK KOMM. GES. May 26, 1965 [July 28, 1964], No. 22453/65. Heading B2L. In mixing goods in particle form, e.g. wood clips with bonding agents, the particulate mat erial is fed from a bin 5 on to a conveyer bell 7 where it is spread and smoothed into a may by rake 17 and conveyed to a metering roll 19 It is thence conveyed in the form of a thick veil 21 into a chamber 2 where it meets a flow of air from a nozzle 27. The latter changes from circular or near square cross section at its inlet 29 to a slit at its exit 30 of the same area and the air discharged therefrom impinges on a concave reflectors 28 so as to be turned through 180‹ and caused to flow back on the outside of said nozzle. This flow of air grades the particles, heavier and larger particles dropping quickly to the coating drum 1 below whilst smaller and lighter particles are carried along by the air flow and fall into the coating drum nearer the exit therefrom. Thus the larger particles remain in the coating drum for a longer period than the smaller ones enabling all the particles to 'be coated to the same degree. In the coating drum the particles are sprayed and mixed with bonding agent from nozzles 50. The mixing is done by a number of side by side agitators consisting of bars 40 mounted on shafts 39 rotated by suitable means disposed outside the drum. The bars 40 of adjacent agitators interleave and are so arranged angularly on the shafts as to produce a conveying motion on the particles from right to left in Fig. 1. At the left hand end of the drum 1 are discharge openings 51 covered by slides 71 and flap covers, both of which can be adjusted to produce the desired discharge according to the through flow of the particles. The flow of particles can be adjusted to give the required degree of coating by adjusting the relative angular disposition of the bars 40 on adjacent agitator shafts 39. A baffle 60, adjustable in position is arranged at the end of drum 1 so that air which may be laden with small particles and bonding agent is caused to pass downwards and through the mass of coated particles before being withdrawn from the drum 1 by blower 31, thus causing the air to be filtered before being recirculated. Various forms of nozzles 27 and reflectors 28 are described (Figs. 13-16, not shown), and ease of access to them is provided for cleaning purposes. The shafts 39 and bars 40 are preferably hollow and a heating or cooling fluid (depending on ambient conditions) can be circulated through them. The drum 1 is so constructed that the ratio of the width of the surface of the particles exposed to the spray nozzles 50, to the depth of particles is at least 3:1 at the normal degree of filling of the drum and the ratio of the length of the agitator arms 40 to the diameter of the agitator shaft 39 is less than 5:1.