Patent GB-818087-A (GB)
Title: Improvements in or relating to devices for decanting liquid from hollow vessels in aprocess applying an internal coating to the vessel
IPC: C23C18/16
Filed: 1956-06-04
Abstract: A device for decanting a liquid from hollow vessels in order that a layer of material, for which the liquid forms a vehicle, may be deposited on the inside wall of the hollow, comprises a turntable 1 which is rotatable about a vertical axis 2 and carries around its circumference a plurality of means upon each of which a hollow vessel can be secured and which can be tilted under the action of control means located at a given position whereby the liquid is decanted. The angular speed of the tilting movement may be varied during decanting, so that it is greater during the last portion of its movement.  In the example cathode-ray tubes 16 are held neck upwards upon a series of small tables 5 which are hingedly mounted between <PICT:0818087/III/1> <PICT:0818087/III/2> pairs of arms or lugs 4 extending radially at the circumference of the turntable 1, the tables 5 being arranged so that they tend to tilt downwardly but are restrained by a rail 14 which encompasses the turntable and engages between a pair of rollers 10, 11 arranged one above the other on the lower part of each table 5. Due to the weight of the table 5 and the vessel carried by it the roller 10 bears upon the upper side of the rail 14, whilst the roller 11, which is carried on a mounting hinged upon a horizontal pin 12, is pulled against the underside of the rail by a tension-spring 13 connected to the fixed mounting for the upper roller 10.  The tables 5 each have a discharge lip 15 for any liquid that may fall thereon, and are provided with a cavity 6 with an edging 7 of resilient material which provides a seating for a cathode-ray tube 16 placed upon it, a hole 8 in the base of the cavity being connected through a pipe 9 to a vacuum source whereby the cathode-ray tube is retained in position.  The tubes 16 with their contents are carried around towards a discharge container 18 adjacent to a portion 17 of the rail 14 which is shaped so that each table 5 tilts about its hinge when the rollers 10, 11 engage it.  In an example cathode-ray tubes placed upon the tables 5 are filled with water with a layer of nitrocellulose solution floating on the surface, and the portion 17 of the rail is so shaped that the first portion of the tilting movement takes place substantially uniformly with a small angular displacement until the layer of nitrocellulose solution has partly laid itself against the screen of the cathode-ray tube.  Subsequently, the angular displacement is increased so that, finally, all the liquid is decanted from the cathode-ray tube into the container 18.  A succession of operations may be carried out upon cathode-ray tubes held on the apparatus.  For example, in providing tubes with a luminescent screen, at one position of the table the tubes may be filled with a liquid in which luminescent material is suspended. During subsequent rotation of the table the luminescent material forms a covering layer on the base of the tube, and at a subsequent stage the liquid may be acidified and a nitrocellulose solution poured into it.  The liquid is finally decanted, during which process a nitrocellulose layer forms upon the luminescent layer.  As an alternative water may be sprayed into the tube at one stage of the decanting process while the tube still has its aperture directed downwards.  The rail 14 may be replaced by another rail in order to achieve variations in the tilting movements.