US3529573A - Pulverizing unit for automatic machine for continuous fabrication of cigarette filters - Google Patents

Description

United States Patent Inventors Appl. No. Filed Patented Assignee Priority PULVERIZING UNIT FOR AUTOMATIC MACHINE FOR CONTINUOUS FABRICATION OF CIGARETTE FILTERS 1 Claim, 5 Drawing Figs.

US. Cl 118/308, 118/323, 239/224 Int. Cl. B05b 7/14 Field of Search 239/223,

References Cited Primary Examiner-Morris Kaplan Attorneys-Robert E. Burns and Emmanuel J. Lobato ABSTRACT: In apparatus for treating cellulosic material with a pulverized plasticizing agent, the material is passed in sheet form through a closed chamber. A pulverizing unit located below the sheet comprises a hollow disc rotating on a vertical axis and having a bottom, a top and a sloping peripheral wall having circumferentially distributed orifices. The plasticizing agent and air are introduced at the center of the hollow disc and are ejected through the orifices by centrifugal force. Spaced radial grooves in the bottom and spaced downwardly projecting radial ribs on the top have the effect of increasing the efficiency of the pulverizing disc.

Patented Sept. 22, 1970 Sheet 1 of 3 Patented Sept. 22, 1970 3,529,573

Sheet 2 of 3 Patented 5ept..22, 1970 3,529,573

Sheet 5 'of 3 PULVERIZING UNIT FOR AUTOMATIC MACHINE FOR CONTINUOUS FABRICATION OF CIGARETTE FILTERS The present invention has for its object a pulverizing installation for automatic machines for the continuous manufacture of cigarette filters, in particular, but not exclusively, for the pulverizing of an agent which plasticizes the cellulosic material used for the making of the filter.

The continuous making of cigarette filters takes place actually by means of an automatic machine which treats at various working posts the raw material used for making the filter, generally, cellulose acetate, which is drawn out and spread out, in a first phase of the treatment to then pass in the form of a sheet or veil of fibers into a plasticizing chamber in which this sheet is impregnated by the pulverization of a plasticizing agent intended to give to the fibers a certain rigidity before passing them through a die which compresses the sheet to give it the desired cylindrical form.

In the plasticizing chambers employed actually, the plasticizing agent is pulverized by centrifugal action by means of a disc rotating around a horizontal shaft parallel to the direction of movement of the sheet. The projection of the plasticizing mist takes place tangentially in all directions. This has for a drawback, on the one hand, that it non-uniformly distributes the plasticizing agent on the sheet, since the plasticizing dispersion which is pulverized increases from one edge to the other of the sheet, and, on the other hand, to project considerable quantities of plasticizing agent on each side of the sheet and above it, which quantities deposit on the walls of the chamber above the sheet, this deposit rapidly forming drops which fall on the sheet forming therein unwanted concentrations of plasticizing agent.

The present invention has for its object the avoidance of the drawbacks above mentioned.

It has for its object a pulverizing unit for an automatic machine for the continuous fabrication of cigarette filters, comprising at least one chamber passed horizontally by the cellulosic material intended to form the filter and arriving in the chamber in the shape of a spread out sheet of fibers to receive a pulverized agent, characterized by the fact that said chamber comprises, below the level of passage of the sheet, centrifugal pulverizing means rotating around a vertical axis ensuring a pulverization, which is directed obliquely upwardly.

This installation is not limited to the pulverization of a plasticizing agent, but can also be used for pulverizing suspensions or liquid dispersions and solid materials, for example particles of carbons in suspension in a carboxymethylcellulose.

The installation can also comprise more than one chamber, for example two successive chambers, one for the application of a plasticizing agent and the following one for the application of a solid, for example carbon granules or aromatic capsules, the plasticizing agent playing then simultaneously the role of fixative agent for the solid particles.

The accompanying drawing represents by way of example a preferred embodiment of the invention.

FIG. 1 shows a front elevational view of the installation.

' FIG. 2 shows a cross sectional elevational view of the installation.

FIG. 3 shows a partial crosssectional view of the pulverizing disc.

FIG. 4 shows a partial plan view of the pulverizing disc of FIG. 3.

FIG. 5 shows a partial cross sectional view taken along line 5-5 of FIG. 3.

In FIG. 1, the frame of the automatic machine for continuously making the cigarette filters is designated by 1. On this frame is mounted a plasticizing chamber essentially formed by a metallic chamber comprising a lower rectangular part Z on which is mounted a cover 3 pivoted on part 2 by a hinge4 and 1 'verizedplasticizing agent in which said material is passed in sheet'form through a closed chamber above a pulverizing unit chamber while the other side has a lamp 7 for lighting the chamber. The sheet of fibers, for example cellulose acetate, enters the chamber through a rectangular opening 8 and comes out through an identical opposite opening 9, the sheet moving in the direction of arrow F.

The horizontal sides of openings 8 and 9 are limited by tubular cylindrical elements 10 and 11, and 12 and 13, respectively. These tubular elements each have a slot or a series of holes 14 extending parallel to the axis of the cylinder, the extremity of a radius directed towards the interior of the chamber and inclined at about 45 in the direction of the sheet passing through the chamber. These tubular elements are connected to a conduit for feeding compressed air, not shown, which escaping from openings 14 forms an air curtain in front of openings 8 and 9, preventing the mist of plasticizer from escaping outside the chamber and depositing on the machine and on the operators. Cylinders 10 to 13 serve also, owing to their rounded shape, to guide the sheet through the chamber without hurting it or ripping it.

Below the sheet, in part 2 of the chamber, is located the pulverizing member constituted by a hollow wheel or disc 15 secured at the end of a vertical shaft 16 turning in a bearing 17 and driven by an electric motor 18 through pulleys l9 and 20 and belt 21. Owing to its particular construction, disc 15 disperses by centrifugal action the plasticizer along a dispersion cone 22. As shown in FIGS. 3 and 4 this disc is hollow. It has a horizontal bottom wall 24 attached to a hub 25 secured to the end of shaft 16, a horizontal upper wall 26 and a conical peripheral side wall 27 connecting walls 24 and 26 and defining a truncated conical cavity 29. The central part of the upper wall 26 has a circular opening 30 permitting the entry of air in cavity 29. In this opening 30 penetrates the extremity of a pipe 31, secured in a manner not shown to a fixed part of the chamber and of the frame. This pipe makes possible the introduction of a plasticizer into the disc. Walls 26 and 27 come together at the periphery of the disc along an oblique flank 32 perforated by a series of channels 33 parallel and tangent to the inner side of the conical wall 27. The plasticizer introduced by pipe 31 in the disc deposits on the bottom of the hollow disc 15 and is driven by centrifugal force, during rotation of the disc, towards the periphery of this hollow disc. The air entering through the opening 30 is also centrifuged and driven out of the openings 33 together with a certain quantity of plasticizer.

The plasticizer is thus pulverized in the manner of an aerosol in an oblique direction 22 defined by wall 27.

The bottom of the hollow disc 15 has radial grooves 34 extending from the hub to the bottom of the conical wall along a radius passing to a channel 33. These grooves have the effect of increasing the flow of the pulverizer, that is the concentration of plasticizer in the mist escaping from the pulverizer. The plasticizer introduced by pipe 31 in effect has a tendency to accumulate in grooves 34 in which it moves in direction of openings 33 by centrifugal action in such a way that a larger quantity of plasticizer arrives at these openings.

Also for the purpose of increasing the efficiency of the pulverizing disc, top wall 26 of the hollow disc 15 carries vertical ribs 35 extending radially between opening 30 and the peripheral part of the hollow disc without however reaching wall 24, but leaving a space 36 for allowing the air and the plasticizer to move more or less freely on the bottom of the hollow in such a way as to ensure a good distribution of the plasticizer. In this case, it is not the plasticizer which is channelled in the direction of openings 33, but air, the disc operating in the manner of a turbine, increasing its pressure and accordingly the efficiency of the pulverizing disc.

" We claim: 1. In an apparatus for treating cellulosic material with a pularranged below said passing sheet, the improvement which maintained in closed position by locks 5 constituted by levers pivoted on part 2. Cover 3 has the shape of a dihedron one of whose sides carries a window 6 for observing inside the- 5 comprises; said pulverizing unit consisting of a shallow discshaped container having top and bottom walls and a slanted a plurality of radially extending downwardly projecting vanes attached to said top wall, power means for rotating said pulverizing unit for expelling through said orifices the plasticizing agent onto said sheet material.

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