US2411660A - Method of making filter cartridges, abrasive sheets, scouring pads, and the like - Google Patents

Description

Nov. 26, 1946. F. w. MANNING METHOD OF MAKING FILTER CARTRIDGES, ABRASIVE SHEETS, SCOURING PADS, AND THE LIKE Filed May 22, 1943 2 Sheets-Sheet 1 lerlllllllllrlllllr'fl Nov. 26, 1946. F. w. MANNING 2,411,660 METHOD OF MAKING FILTER CARTRIDGES, ABRASIVE SHEETS, SCOURING PADS, AND THE LIKE Filed May 22, 1943 2 Sheets-Sheet 2 Patented av. 26, 1946 Email METHOD OF MAKING FKLTER CARTRIDGES, ABRASIVE SHEETS, SCOURING PADS, AND

THELIKE Fred W. Manning, Palo Alto, Calif. Application May 22, 1943, Serial No. 488,317 12 Claims. (Cl. 154-401) My invention relates to the manufacture of non-woven fabrics from'pla'stics for abrading, scouring, filtering and similar purposes, and more particularly to non-woven fabrics built up into integral laminated pads for use in air cleaners and oil filters. This application is a continuation-in-part of my copending applications: Spun fabrics, Serial No. 423,733, filed December 20, 1941; and Laminated non-woven fabrics," Serial No. 439,026, filed April 15, 1942.

Hithertofore it has been the practice to use wire, hair, etc., in liquid-bath type air cleaners for internal combustion engines. Various means were used to incorporate kinks and curls in such articles forthe purpose of making tortuous paths therein and thereby increasing the interstices and the wetting surfaces for passage of the air to be cleaned. Unfortunately, no method had ever been developed, as far as I am aware, for standardizing the size, spacing, etc. of the fibres. They were simply rolled up, usually by hand, compressed, and introduced into a receiver with the result that the lack of uniformity in the size and number of the voids and the variance in the wetting surfaces resulted in inefficiencies and inequalities that necessitated over large containers for the filtering pads. Furthermore, this lack of uniformity in conjunction with insuflicient resiliency of the fibres often resulted in channeling of the airthrough the fibres, especially at the perimeter of the container. And, of course, it is impossible to regulate the size of most animal and vegetable fibres. I

,An object of my invention therefore is to provide a method for standardizing the crimping and spacing and compacting of the fibres in a container so that the resultant increase in the eiiiciency and capacity of the fibres will make possiblea substantial reduction in the size of the container and the amount of fibres required.

' Another object is to make a further reduction in the; size of the container possible by utilizing finer diameter fibres to build up smaller pads having the same wetting areas and size and percentage of voids as formerly provided by the greater diameter fibres in the larger size pads.

A further object is to provide a readily adjustable means for varying the size and spacing of the fibres, and size and number of the interstices, etc., to suit different atmospheric conditions, viscosities of the oil bath, sizes of air cleaner, etc.

Another object is to provide a cartridge type of pad for recharging types of air cleaners and oil filters, and to make the fibres firmly adhere to the sides of the containers of those filters that may not be recharged.

An additional object is to standardize fibre conditions so that the efliciency of any air cleaner or oil filter of a given size for a given purpose is exactly the same as the efficiency of another cleaner or filter of the same size for the same purpose.

A still further object is to provide a cartridge type of pad in which is incorporated treating solids, such as may be used for filtering, decolorizing, catalyzing, abrading, and other purposes.

In accordance with my invention, I propose to use spinning materials, which are usually thermoplastic but may be thermosetting. A great variety of plastics may be used for the purposes mentioned above, such as vinylidene chloride, polystyrene, polysulphide, polyvinyl alcohol, polyvinyl acetate, methyl methacrylate, polymeric amide, copolymer of vinyl chloride and vinyl acetate, latex compositions, cellulosic and petroleum derivatives, protein-base materials, glass, and almost all organic and inorganic materials that are now spun or extruded or cast into filaments, films, and foils; and such materials may be modified by other materials, such as, plasticizers, coloring agents, volatile solvents, etc.; but which are most suitable for any particular purpose will depend upon the temperatures involved, corroding effects of the fluids to be filtered, cost of the plastics, and many other factors.

Plastics may be spun from a fluid state, which may into either continuous or discontinuous filaments, and the filaments, deposited in wavy or other irregular patterns in which there is absolute uniformity in the spacing of the filaments and the number and size of the voids throughout successive layers of the fibres. The filaments may be extruded from a spinneret by a pressure difierential on the plastic within .the spinneret, and pull on the filaments being extruded; they may be conveyed and stretched by meansof the pullof an elastic or a liquid fluid, or by positive pull of a wind-up bobbin or a depositing surface moving at a greater speed than the extrusion speed of the filaments; and elastic fluids, such as air, nitrogen, helium, argon etc., or liquid fluids, such as water, oil etc., may be used for heatin8, quenching, conveying, stretching, shrinking, solvent recovery, and depositing the filaments.

An electrostatic field may be used to shatter a molten, solution, or other fluid stream of plastic material into disrupted filaments and build them into a pad of successive webs of uniformly or be a molten, solution, or other condition,

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rectify the usual alternating current to give a pulsating unidirectional voltage of 50,000 to" 100,000 volts, or more, that may be required. The dispersing electrode may be the spinning nozzle, or it may be placed near the nozzle, and the collecting electrode may be a retaining wall, or it may be placed below the wall, and either or both electrodes may move intermittently, or relatively to the other, or may be charged with varying potentials, to vary the size, crimping, compactness, etc., of the fibres being deposited on the wall or in a container. The electrostatic field may also be used to supplement the action oi elastic or/and liquid fluids used for the various spinning operations, such as, extruding, dispersing, disrupting, stretching, quenching, solvent recovery, and depositing. the fibres.

The invention is exemplified in the following description, and a preferred arrangement is illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a vertical section of one form of apparatus for building up filter cartridges; Fig. 2, a part vertical section and part elevation of a modified form of the apparatus shown in Fig. 1; Fig. 3, a fragmentary sectional view of another type of apparatus for constructing the filter pads; Fig. 4, an enlarged view of a cross-section of the discharge nozzle taken on line 4-4 of Fig. 3; Fig. 5, a vertical section of a filter recharge; and Fig. 6, a plan view of Fig. 5.

Referring to the drawings, more specifically by reference characters:

Fig. 1 shows an arrangement in which a spinning gun is placed in a fixed position for reducing a plastic rod I to a molten state and disrupting it into filaments. The gun consists of: guide block 2 for the plastic rod; heating element 3 with which the plastic rod is held in pressural contact; spinneret opening 4 in the heating element for the molten plastic; cap 5 for enclosing the guide block and heating element; upper Venturi tube 6 which is adjustable in the end of the enclosure cap; lower Venturi tube 1 which is adjustable in the end of the upper Venturi tube; feed drive roller 8 fixed to a shaft 9 that is driven by a motor l connected to the electric circuit wires II and I 2; bracket l3 attached to the cap enclosure and which supports the drive roller; cam i4 whose rotation gives an up and down movement to the gun by virtue of the latters weight, and results in an undulating curve to the fibres as they are deposited; cam

drive shaft i supported by a bearing 16 and driven from a source of power, not shown; bracket I! that is pivoted by pin l8 to the enclosure cap and supports feed roller IS, the spring 20 causing the plastic rod to be held in frictional contact between the feed rollers so that the rotative movement of either will result inpressurai contact of the rod against the heating element and cause a continuous filament to be extruded from the spinneret opening; pipe connection 2i for supplying aprimary elastic fluid in the form of an annular concentric column about the molten stream for heating, stretching, conveying and solvent recovery, and when necessary, disrupting the filament into a plurality of broken filaments; pipe connection 22 for supplying a higher velocity secondary elastic fluid also in the form of an annular concentric column for enclosing, controlling, and directing the filaments conveyed by the internal annular column of heated elastic fiuid, but the fiuid from pipe 22 may also be used for conveying treating solids, stretching and quenching the filaments, and solvent recovery purposes. A cover 22 having an inlet 24 for a quenching fiuid, is rigidly attached to the gun nozzle but has a sliding fit over the fibre receivin portion of the filter. The latter consists of container 2!, central tube 22, and a foraminous retaining wall 21, which usually travels at a much greater speed than the extrusion speed of the filaments.

A rotating mechanism for charging the container comprises: receiver cup 28 connected to an upper friction plate 29 by annular shaft 30; hollow shaft-3l having a keyway 32; lower friction plate 33 equipped with a key 24 to slide in the keyway and permit the lower friction plate to move freely up and down the hollow shaft; a worm gear I! keyed to the hollow shaft and driven by worm 26 from a source of power not shown; and the bracket 31 equipped with the upper and lower'bearings 28 and 32, respectively, the latter having an annulargroove 40 that connects with ports 4| of the hollow shaft for escape through the outlet pipe 42 of the spinning, quenching, and other treating fluids.

A retraction apparatus for maintaining the charging'space constant between the gun nozzle and retaining wall is placed at the side of the rotating mechanism, and consists of fulcrum lever 43 pivoted centrally by Pin 44 to the bearing bracket; hand lever 45 for pulling the fibre container into its top charging position; ball bearing 48 on which the drive friction plate rotates; spring 41 to retract the container as the latter becomes charged; air compression cylinder 42 pivoted by means of cover plate 49 and pin II to the fioor bracket 5i; piston 52 attached by piston rod 53 and pin 54 to the fulcrum lever; check valve 55 in the piston to allow the latter to be moved readily On the downward stroke but which closes on the upward stroke; and an air vent 5B controlled by screw 51 to regulate the speed of the upper stroke and consequently the retraction speed of the fibre container. When the container has been fully charged and its cover is clear of the former, the shoulder of the rotating cup will contact the upper bearing of the rotating mechanism and thereafter any further upward movement of the piston will disengage the friction plates of the driving clutch and the container will cease to rotate, and simultaneously therewith stud 58 will touch the contact point 59 thereby breaking the electric circuit to the driving motor for the plastic feed. The gun and the container cover can then be swung out of position and the charged container removed.

Fig. 2 is a modification of the arrangement shown in Fig. 1, in which a plastic material in molten, solution, or other fiuid condition is extruded as a stream into a high potential electrostatic field formed between the spinning gun as the dispersing electrode, which is charged positively, as indicated by the plus sign, and the rotating mechanism and container as the collecting electrode, which is charged negatively, as indicated by the minus sign, and grounded. The dispersing and collecting electrodes are connected by conductors I0 and H, respectively, with a source of high potential 82 with the result that the former will shatter the plastic stream into disrupted filaments that will be constantly repelled by a pulsating unidirectional current and attracted to the collecting electrode of opposite and the deposition of the fibres within be supplemented and accelerated by passage of an enveloping elastic conveyin! and stretching fluid through the foraminous retaining wall or. the container and out through the hollow shaft 03 of the receiver cup and outlet ll inthe i'oot-stepbearing OI. Both electrodes move during the chargin operation; the container in a rotative direction around a vertical axis while the gun is retracted upwardly by the hand lever I. actuated by a spring I! operating against the air compression cylinder position on the stand 80.

Figs. 8 and 4 show an arrangement whereby continuous or discontinuous filaments may be spun from a continuous extruding machine, and deposited in a container rotated and retracted in similar manner to that described in Fig. 1. The arrangement shown includes: torpedo end of screw ll, extrusion cylinder 10, extrusion elbow Tl, jacket 12 for a heating or cooling medium, die block or spinneret ll, die block cap I4, and spinpo y. the container may ning nozzle ll to which the container cover is attached. A fluid inlet ll connects with an annular distributor channel 11 in the die block for openings 18 to provide a plurality of streams of elastic fluid for enveloping, conveying, and stretching, the filaments extruded through the openings 19. If the streams of elastic fluid are constant inpressure and direction, the plastic may be extruded, stretched, and deposited in continuous filaments; if the streams are intermittent, as would result from constantly rotating a valve Ill in the elastic fluid inlet, the filaments may be stretched and deposited in a disrupted condition, the length of the filaments depending upon the length or time in the cycle that the elastic fluid pressure is constant, and such conditions will be equally applicable to filaments spun from a molten or solution condition with other types of apparatus, such as shown in Figs. 1 and 2. A quenching fluid such as water, may be introduced into the nozzle I! through the es I0, I1 and 18 instead of an elastic fluid, or the quenching fluid may be introduced through inlet in the container cover and escape through the retaining wall of the container, or by overflowing the central tube of the container.

Figs. 5 and 6 indicate a recharge arrangement in-which the annular space between tubes 8| and 02, which may be made of paper or other suitable foraminous or impervious material, is filled with flbres ll. This may be accomplished by slipping the larger tube inside the container wall 25 and the smaller tube over the container outlet 28, and filling the annular space in the usual way, after which the recharge may be removed from the container. Or, a cylindrical cartridge may be built up without the aid of the inner tube 02 and the container outlet 28. The recharge, with or without enclosing tubes, may then be inserted in a suitable receptacle for axial or radial filtration purposes such as are described in my Patent Nos. 2,055,870; 2,093,090; 2,128,589, and 2,218,339.

It will be evident from the foregoing description I that a plastic in a solution, or other fluid condition, may be substituted for the molten plastic in Fig. l, and that several of the essential operations involved in the production of a filament are: disruption of the fluid plastic into a filament by a differential pressure on the plastic within a container that has a filament orifice, and by direct pull on the filament after it has been started through the orifice; stretching the extruded filament by a liquid or an elastic conveying fluid 6 moving in the direction of the extrusion travel of the filament but at a greater speed than the said travel, or by deposition of a portion of the filament on a retaining wall to ,which it adheres moving at a speed in excess of the undeposited portion; deposition of the stretched filament on a retaining wall preferably by passage therethrough of an enveloping elastic fluid used for conveying, stretching, solvent recovery, and other.

purposes; and the quenching of the extruded filament during the stretching or'after deposition by means of a cooling fluid, preferably passing through the retaining wall. A continuous filament can thus be extruded and its continuity maintained, providing the pressure and volume of the fluid enveloping it for stretching and conveying purposes is constant and the fluid properly streamlined in the direction of the filament travel, but the filament may be readily disrupted into a multiplicity of broken filaments by altering these conditions, and the broken filaments may be standardized in length by making such changes periodic. An electrostatic field of high potential may also be used independently, or to supplement the action of elastic fluids, for such operations as the shattering of a fluid stream, or a plastic filament, into a multiplicity of broken filaments, and the conveying and depositing of the disrupted filaments, and the removal of a solvent therefrom.

It will also be evident: a number of continuous filaments may be continuously extruded, stretched, etc. from a plurality of spinning orifices or guns connected with a common body of plastic, or source of supply; a film or sheet of parallel individual filaments may be extruded from a slot or series of orifices connected with a common source of supply, and enclosed within streams of elastic or other treating fluid directed from both sides of the plastic sheet for stretching, disrupting, quenching, solvent recovery, and other purposes; the filaments may be crimped in a wavy manner with the waves undulating in a vertical direction caused by a rapid relative withdrawal and advanceof the spinning gun and receiver, or with waves undulating in a horizontal direction caused by a rapid relative lateral movement of the gun and receiver; the filaments may be deposited in superposed layers on a retaining wall having a vertical rotating axis to form an integral filter bed of helically wound fabrics, or they may be deposited in superposed layers on a retaining wall having a horizontal rotating axis to form an integral filter bed of spirally wound fabrics; and simultaneously with the building up of such filter beds there may be incorporated therein clay or carbon for decolorizing purposes, pumice stone and water soluble soap for scouring pads, fused alumina, corundum, etc., for abrasive sheets, catalyzing agents for catalyzing purposes, or other treating solids for other purposes. After completion of the filter bed forming operations the bed may be removed and cut into pads of various shapes and sizes suitable for the purposes for which the pads are to be used.

It will furthermore be evident: the filaments may be deposited in a condition in'which they will be sufficiently adhesive to adhere to the sides of the container, or the walls of a recharge, or a layer of filaments previously deposited; a top layer of filaments, or all the layers previously deposited, may remain in an adhesively plastic condition until a subsequent layer has been deposited; and that a plurality of intersecting filaments bonded together in a layer by their own adhesiveness will form an integral fabric, and a plurality of integral fabrics bonded together by their own adhesiveness will form an integral pad or bed. However, the filaments may, when desirable, be sufficiently quenched or indurated to be deposited in a discrete condition, in which case, they may be bonded together and to the walls of their container or cartridge by an adhesive introduced in powder, atomized, or liquid form, into the container through any suitable opening, such as 24, during the charging operation; or a bed of discrete filaments may be bonded together by passing through the bed a solvent of the fibres in vapor or liquid form; or the filaments may be deposited in an adhesively plastic state to one another but without adherence to the walls of their container, providing the latter has first been lubricated with oil, wax, gelatine, etc. After the charging operation is complete fiuids, such as,

hot water, hot air, etc., may be introduced through opening 24 into the container to render the adhesive effective, remove a solvent, shrink the fibres, indurate the filaments, etc., and may escape through outlet 42. Distillation of a solvent of the fibres should however be accomplished sufliciently rapidly to limit the action of the former and to retain the interstices amongst the fibres, and may be accompanied by a certain amount of pressure from the heated air to make the adhesive action of the solvent more effective.

It will thus be seen: the diameter of the filaments may be varied by varying the size of the extrusion orifices and the stretching given to the filaments, and by such means the diameters of the filaments can be uniformly reduced to give greater surface areas and percentages of voids than formerly obtained for the same volumes or weights of fibres; the filaments may be deposited in uniformly spaced wavy or undulating lines that parallel or intersect by regulating the relative movements of the extrusion device, or plurality of extrusion devices, and a receiver; the filaments may be deposited in continuous lengths, or they may be deposited in standardized broken lengths by regulating the continuity, direction, force, temperature, etc., of the spinning fiuids; and the compactness of the deposited layers may be kept uniform by standardizing the temperature and pressure of the spinning fluids, particularly those that pass through the filter bed.

I claim as my invention: 4

1. A method of making articles of the character described comprising: reducing a spinning material to a fluid condition; disrupting the said fluid material into a plurality of filaments; and A depositing the said filaments in an adhesive and intersecting condition upon a retaining wall moving in an endless path to build up a succession of integral fabric windings in which each successive winding is deposited in a sufficiently adhesive condition to adhere to its adjacent winding.

2. A method of making articles of the character described comprising: reducing a spinning material to a fluid condition; disrupting the said fiuid material into a plurality of filaments;

depositing the said filaments in an adhesive and intersecting condition upon a retaining wall moving in an endless path to build up a succession of integral fabric windings in which each successive winding is deposited in a sufficiently adhesive condition to adhere to its adjacent winding; and incorporating and bonding treating solids in each successive winding as the winding is deposited.

3. A method of making'articles of the character described comprising: reducing a spinning material to a fiuid condition; disrupting the said fluid material into a plurality of filaments; subis deposited in a sufficiently adhesive condition to adhere to its adjacent winding.

4. A method of making articles of the character described comprising: reducing a spinning material to a fiuid condition; disrupting the said fiuid material into a plurality of filaments; subjecting the said filaments to a positive pull to stretch the filaments; depositing the extended filaments in an adhesive and intersecting condition upon a retaining wall moving in an endless path to build up a succession of integral fabric windings in which each successive winding is deposited in a sufllciently adhesive condition to adhere to its adjacent winding; and incorporating and bonding treating solids in each successive winding as the winding is deposited.

5. A method of making articles of the character described comprising: reducing a spinning material to a fluid condition; disrupting the said fiuid material into a plurality of filaments; depositing the said filaments in an intersecting condition upon a retaining wall moving in an endless path to build up-a succession of fabric windings; and incorporating and bonding treating solids in each successive winding as the winding is deposited.

6. A method of making articles of the character described comprising: reducing a spinning material to a fluid condition; disrupting the said fluid material into a plurality of filaments; subiecting the said filaments to a positive pull to stretch the filaments; depositing the extended filaments in an intersecting condition upon a retaining wall moving in an endless path to build up a succession of fabric windings; and incorporating and bonding treating solids in each successive winding as the winding is deposited.

'7. A method of making articles of the character described comprising: disrupting a, fluid plastic material into a plurality of filaments; depositing the said filaments in an adhesive and intersecting condition upon a retaining wall moving in an endless path to build up a succession of integral webs in which each successive web is deposited in a sufiiciently adhesive condition to adhere to its adjacent web; and waving the said filaments during the said depositing to incorporate crimps in the said webs.

8. The method of making articles of the character described comprising: disrupting a fluid plastic into a plurality of filaments; depositing the said filaments upon a foraminous retainin wall moving in an endless path to build up a succession of webs of intersecting filaments having interstices thereamong; bonding the said filaments of each of the said webs at the said intersections; and passing a fluid stream through the said interstices and retaining wall during the said bonding.

9. The method of making articles of the character described comprising: disrupting a fluid plastic into a plurality of filaments; conveying the said filaments by force of a fluid stream; and passing the said stream through a foraminous retaining wall moving in an endless path t deposit the said filaments and build up a succession of integral webs in which each web is deposited in a filaments byforce of a v taneously introducing treating solids into the said suiflcientiy adhesive condition to adhere to its adjaeent web.

10. The method of making articles 01 the character described comprising: disrupting a plastic into a plurality of filaments; conveying the said filaments by force of a fluid stream; passing theisaid stream through a, wall moving in an endless path to deposit the said filaments and build up a succession of integral webs in which each web is deposited in a sufllciently adhesive condition to adhere to its adiacent web; and incorporating and bonding treating solids in each successive web as the web is deposited.

11. The method of making articles of the char- :acter. described comprising: disrupting a fluid plasioraminous retaining l0 raminous retaining wall moving in an endless pa to deposit the said filaments and solids and build up a succession o1 webs in which the filaments or each web are deposited in a sufllciently adhesive condition to bond the solids within the web,

12. The method of making articles of the character described comprising: disrupting a fluid plastic into a plurality of filaments; subjecting the said filaments to a positive pull to stretch the ills.- ments; depositing the extended filaments in an adhesive and intersecting condition upon a totic into a plurality of filaments; conveying the said I fluid stream and simulstream; passing the said stream through a toraminous retaining wall moving in an endless path to build up a succession of integral webs of intersecting filaments having interstices thereamong; incorporating and bonding treating solids in each successive web as the web is deposited; and passing a fluid stream through the said interstices and retaining-wall during the building up of the said succession of webs.

FRED W. MANNING.

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