GB459043A - Improvements in or relating to method of and apparatus for treating substances and forming films - Google Patents

Abstract

<PICT:0459043/III/1> Films of flowing liquid maintaining continuity and uniformity of thickness over a considerable area without solid support are obtained by adopting means to counteract the tendency of surface tension to contract or break up the film. Said means may be (1) giving the liquid a velocity component along the film-forming edge or slot as well as away from it, (2) in the case of an annular film giving the liquid an outward velocity component, (3) maintaining the lateral extension of the film by contact with guiding wires extending in the direction of flow. The invention is particularly applicable to irradiation processes and the film may constitute the liquid to be treated and/or it may serve as a light filter or gas barrier between that liquid and the source of light. Fig. 1 shows an irradiation apparatus in which the liquid to be treated passes from an annular trough 24 through perforations 32 to a passage 31 from which it issues as a film between lips 28, 30. A tangential motion is imparted to the liquid either by the direction of the passages 32 or by deflectors at their outlets. An outward velocity component is also imparted <PICT:0459043/III/2> <PICT:0459043/III/3> <PICT:0459043/III/4> <PICT:0459043/III/5> by adjusting the outer lip 28 to a lower leve than the inner lip 30. Alternatively the whole annular nozzle may have an outward aspect as in Fig. 7, or the film may be formed by causing it to impinge against a single surface 75 as in Fig. 9, the lower edge being suitably shaped as at 76 to eject the liquid in the desired direction. The annular film 50 is received on the lower part of the surrounding reflector 106 and corrected in a trough 107. Between it and the lamp 35 is disposed a second film 61 produced by similar means to act as a filter or screen. Fig. 13 shows the production of a plane film which is prevented from contracting by giving the liquid a motion from the centre to both ends of the distributing trough 160. The two outer edges 162 of the film become thickened and as treatment may thus be impaired they may be separately collected as shown. Fig. 15 shows a plane film in which guide wires 171 are disposed. The Specification as open to inspection under Sect. 91 comprises further details corresponding to the subject-matter of Specification 459,118. This subject-matter is disclaimed in the Specification as accepted.