Abstract A coating apparatus and method are described in which a knurled applicator roller is employed to apply a slurry of suspended particles to the surfaces of articles of different shape. The applicator roller is motor driven and partially immersed in the slurry solution so that it agitates such slurry as it is rotated to prevent settling of the particles. The articles are fed onto the applicator roller from an idler roller. An adjustable scraper blade is supported adjacent the applicator roller to control the thickness of the slurry layer provided on such roller. The present apparatus and method is employed to apply a coating of a slurry of glass frit particles suspended in a solution of organic binder and solvent, to the end of the funnel portion of a cathode-ray tube envelope in order to enable such glass frit to form a seal between such funnel portion and the faceplate of such envelope.
A method in accordance with claim 1 in which the glass frit is made of a devitrifiable glass and the seal is heated during sealing for sufficient time to cause at least part of the glass to crystallize.
Claim 2
Dependent Claim
50 words
A method in accordance with claim 2 in which the slurry also includes a solution of organic binder and a solvent and the heating removes said binder at a lower temperature than the sealing temperature of the glass so that the seal is free of said binder and said solvent.
Claim 3
Dependent Claim
21 words
A method in accordance with claim 3 in which the binder is nitrocellulose and the solvent is ethylene glycol monobutyl ether.
Claim 4
Dependent Claim
28 words
A method in accordance with claim 1 in which the funnel portion is made of a crystalline ceramic material and the faceplate portion is made of a glass.
Claim 5
Dependent Claim
34 words
A method in accordance with claim 5 in which another seal is made in a similar manner between a glass neck portion of the envelope and the other end of the ceramic funnel portion.
Claim 6
Dependent Claim
25 words
A method in accordance with claim 1 in which the slurry is held in a container and stirred by rotating the roller in said slurry.
Claim 7
Dependent Claim
42 words
A method in accordance with claim 1 in which the thickness of the slurry layer on the roller is varied by moving a scraper member to change its spacing relative to the applicator surface of such roller to compensate for different conditions.
Claim 8
Dependent Claim
35 words
A method in accordance with claim 1 in which the slurry layer is held on the roller by a knurled surface and the tips of the knurl projections contact the surface of the funnel portion.
Claim 9
Independent Claim
161 words
A method of joining two preformed bodies at least one of which is of ceramic material having a random configuration along the surfaces to be joined, comprising the steps of: depositing a coating material including glass frit in a container to provide a pool of coating material; immersing a roller having an applicator surface with raised and recessed surface portions in said pool of coating material; rotating said roller in position in said container so that said coating material is carried by said applicator surface from said pool to a coating position; moving a random surface of one of the preformed bodies along said applicator surface at said coating position to apply a layer of said glass frit coating material on said random surface; heating the coated body to melt the glass frit layer; assembling said bodies so that the random surfaces are together with said layer of coating material therebetween; and maintaining said random surface together until they are joined.