Patent GB-798118-A (GB)
Title: Improvements in and relating to the manufacture of tobacco smoke filter wads
Inventor: RUBACK SYDNEY
IPC: A24D3/02
Filed: 1953-10-19
Abstract: 798,118. Cigarette-mouthpiece making machines. CIGARETTE COMPONENTS, Ltd. Oct. 6, 1954 [Oct. 19, 1953], No. 28839/53. Class 130. [Also in Groups VIII and IX] A filtering substance is added in a finely divided state to a fibrous web while the fibres are in a loosely coherent state such that the web is incapable of being reeled into a supply roll, and the web is then either formed into rod shape and subsequently divided into filter wads or formed with a web of sheet material into a composite web which may be re-rolled and subsequently used in a filter rod machine. Fibrous material such as cotton, regenerated cellulose, or synthetic fibres is fed to a carding machine as described in Specification 639,919 and the resulting thin web 11, Fig. 1, of loosely coherent fibres is delivered from the discharge cylinder 10 on to a doffer cylinder 12 from which it is removed by a picker 13 on to a crepe paper web 14. A filtering substance in the form of a solution or slurry is sprayed on to the web 11 through nozzles 20 and the composite web passes through a heater 23 wherein the filtering substance is converted to a dust or powder dispersed amongst the fibres. The composite web is reeled on a winding-up drum to form a supply roll which is subsequently used in a machine such as that described in Specification 661,626 to form filtering wads. Examples of the added filtering substances are: anion and cation exchange materials, carboxylic acids, ferric chloride, manganese dioxide, cobalt oxide, potassium bitartrate, magnesium oxide, sodium bisulphate, sodium bisulphite, charcoal, surface-active alumina, silica gel, and diatomaceous earth. Substances which are more active in the moist condition may have small quantities of a hygroscopic material such as sucrose or calcium chloride added thereto and substances which are soluble in solvents such as water, ethyl alcohol and toluene are preferably added to the fibres by spraying. Insoluble substances may be sifted or sprinkled on to the fibres or formed into a slurry. An adhesive substance may also be added to the added substance. In Fig. 5 the loose fibrous web 11 from the carding machine is divided by a knife 33, each half of the web being moved sideways by conveyers 35, 36 and formed into a sliver 38. A solution of a filtering substance is sprayed on to one half of the web at 20 and asolid filtering substance is delivered down a shaking conveyer 31 on to a reciprocating sieve 32 which sprinkles the substance on to the other half of the web. In Fig. 6 the fibrous material is fed to a chamber 42 where it is broken up by toothed rollers 43, a vacuum maintained in the top portion of the chamber causing a thin web 46 of loose fibres to be deposited on an endless sieve 44 passing through the chamber. The web 46 is picked off the sieve 44 by a roll 47 and fed on to a crepe paper web 14, and the filtering substance may be added either by a spraying assembly 20 within the chamber 42 or bv a sieve 32 situated above the web 14. A second crepe paper web may be added to the composite web at 28.