US 3474703 A
Description (OCR text may contain errors)
Oct. 28, 1969 w, v s ETAL CAPILLARY DEVICES .Filed May 10, 1966 FIG. I
INVENTORS WILLIAM J. DAVlS RICHARD o. CHURCH BY W M ATTORNEY United States Patent 3,474,703 CAPILLARY DEVICES William J. Davis, Wyomissing, and Richard 0. Church,
Reading, Pa., assignors to Arthur D. Little Inc., a corporation of Massachusetts Continuation-impart of application Ser. No. 476,177,
July 30, 1965. This application May 10, 1966, Ser.
Int. Cl. D02g 3/36; D02j 3/18 U.S. Cl. 87-1 31 Claims ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of our copending application Ser. No. 476,177 filed July 30, 1965, now abandoned.
This invention relates to capillary devices adapted for use in the transmission of fluids and, more particularly, to those capillary devices that are comprised of a plurality of filaments, and methods for their manufacture.
It is known that filaments can be bundled together in such a manner as to form small capillary spaces between the various filaments. These have been and continue to be used in many successful applications, such as for wicks and the like. Recently, it has proved especially desirable to prepare such capillary devices from filaments made from the various synthetic resinous materials that are readily available in fibrous form. By way of example, the polyamides, polyesters, polyacetals, polyolefins, polyvinyl chlorides, and the polycarbonates may be mentioned. Fibers prepared from these resins are particularly advantageous in forming capillary devices since they are relatively inert in common environments; they have good strength; they wear well; they can be prepared in given and uniform diameters; and they can be bonded together with facility. By and large, these advantages are not obtained when natural organic filaments, such as prepared from cotton or wool, are used.
In the preparation of capillary conduits from filaments, it is conventional to arrange a plurality of them in spaced relationship to each other to form capillary openings for conducting fluids between the several filaments. For example, one simple type of capillary device of this sort can be prepared by axially orienting a bundle of filaments and bonding the various filaments to each other at their points of tangency. The bonding can be accomplished by any conventional means, such as by gluing; by fusing, either using heat or solvents; or various combinations thereof.
The manner and degree to which the various filaments are bonded to each other assumes considerable importance and may affect to a significant degree the properties of the capillary device. Not only does the bonding secure the filaments in spaced relationship to each other to establish the capillary spaces, but also the degree of bonding affects the stiffness and strength of the bundle and the flow characteristics of fluids through the bundle.
The physical and mechanical properties of these capillary devices are especially important when the capillary device not only serves as a conduit for the transmission of fluids, but also, one of its ends is used to apply and 3,474,703 Patented Oct. 28, 1969 distribute fluids over a surface. Lubricating wicks and pen points are common illustrations of these. In these applications, in addition to providing for an adequate flow of fluid, the capillary device must have good mechanical properties and a firm, non-wearing applicator tip. Since this type of utilization is the most critical and has the most stringent requirements, the following description of the invention is particularly directed to the preparation of capillaries for use in these applications. It should be understood, however, that these devices may also find utility for many other purposes, such as in transmitting lubricating fluids, both as a permanent lubrication line leading from a sump to a bearing and as a line for intermittent use as with an oil can; as transmission lines for feeding various liquid fuels; for transmitting and applying medicinal and cosmetic products; for transmitting water, such as in humidifying devices; and multivarious other purposes that will readily occur to those skilled in the art.
While somewhat of a generality, it is reasonable to state that the strength and stiffness of a filamental capillary device, as well as the wear characteristics of its applictor end, are improved by increased bonding between the various filaments. On the other hand, it is readily understandable that as the amount of bonding between the filaments is increased, the cross sectional area of the capillary spaces will tend to decrease or become blinded with a resulting diminution in the rate with which fluids will flow through the capillary device. Accordingly, the known capillary devices of this type necessarily compromise either mechanical properties to obtain an adequate feed rate, or the feed rate to obtain the desired mechanical properties. With specific regard to capillary devices that have been used in the preparation of pen tips, it is known that those tips that feed well are weak, do not wear well, bend or otherwise deform under writing pressure, and, most annoyingly, are subject to a fraying or separation of the filaments at the end of the tip that destroys the pens utility as a fine writing instrument. On the other hand, some writing tips comprised of bundles of filaments have been made that have considerable strength, wear well, and hold a fine point. Unfortunately, these capillary devices are generally unsatisfactory due to their poor rate of feed.
A further restriction upon the performance of these capillary devices lies in the fact that since the filaments are axially oriented and bonded at their lines of tangency, only axial flow of fluids can take place and radial flow is substantially excluded. This may be of consequence both at the feed end and at the applicator end of the capillary device.
Accordingly, it is an object of this invention to provide improved capillary devices comprised of filaments.
Another object of this invention is to provide methods and means for bonding filaments together to form a strong capillary device while not unduly restricting the capillary spaces between the various filaments.
Yet another object of this invention is to prepare a capillary conduit for the transmission of fluids which communicates with a source of fluid at one end and serves to apply and distribute the fluid onto a desired surface at the other end.
Still another object of this invention is to provide capillary devices having high feed rates that are comprised of a plurality of filaments securely bonded together to provide good mechanical properties of strength, stiffness and wear.
And still another object of this invention is to provide novel means for securing filaments together in the form of improved capillary devices that have high strength and stiffness, good characteristics of wear, good characteristics of fluid transmission, and strong, longwearing applicator points.
And yet another object of this invention is to provide fine, long-wearing tips for writing instruments.
And yet another object of this invention is to provide capillary devices comprised of bonded filaments that will enable fluids to pass in both radial and axial directions therethrough.
Briefly, these and other objects of this invention are achieved by weaving filaments into a braid and then adhering adjacent filaments of the braid to each other as by the use of heat, solvents, adhesives, or the like. If the filaments are adhered to each other in a proper manner, as described in detail below, it has been discovered that a capillary device combining properties of good fluid flow and high strength can be produced.
FIG. 1 is a side view of the capillary device of this in vention; and
FIG. 2 is a view taken through line 22 of FIG. 1.
Referring to FIG. 1, there is shown a braided capillary device 1 suitable for the transmission and application of fluids. One end of the device 1 has been reduced in diameter and given a rounded tip as would be desirable, for example, if the device 1 is to be used as a writing in strument.
FIG. 2 illustrates the construction of the device of FIG. 1 in which the braided device 1 is comprised of an outer braid 2 braided around an inner braid 3.
It is thought that when adjacent filaments of the braid are properly bonded together in accordance with the teachings of this invention, the bonding occurs primarily at the intersection of these filaments where essentially point contact is made. It is believed that this prevents the capillary spaces from becoming blinded and thus the flow of fluids through the capillary device is not restricted in either an axial or radial direction.
In preparing capillary devices in accordance with this invention, it may be found useful to use a plurality of concentric braids. By this means, small diameter filaments may be utilized to provide a small diameter braid, and by braiding concentric layers over the initial braided structure, a capillary device of the desired diameter can be built up.
Sometimes it may be desirable to provide a small central passageway in the interior of the innermost braid. While it is true that there will always be a small passageway in the center of a braid, this passageway may collapse or become plugged during the bonding operation. To avoid this, the filaments can be braided around a core piece which, after the braid has been bonded, can be removed from the center of the braid. For example, a fine filament that will be unaffected by the bonding agent can be used as the core piece and pulled out of the center of the braid after the braid has been bonded. Alternatively,
a soluble filament can be enclosed in the central portion r of the braid and removed by a dissolution process.
Due to the fact that the braided construction can be bonded together to form a strong mechanical structure, it is also possible to include one or more filaments within the central passageway of the braid. These filaments may be permanently included at the time of braiding and firmly held in position by the bonded braid. By providing axially oriented filaments in the central passageway of the braid, the flow characteristics of the capillary device can be altered.
The flow through the capillary device will also depend upon the diameter of the filaments used in preparing the braid. It can be appreciated that the larger the diameter, the larger will be the open areas between the various filaments of the braid and, accordingly, the greater will be the rate of flow. Also, some control over the open areas can be obtained by using filaments having differing diameters or filaments having non-circular cross sections (multi-lobal). In both cases, the geometry of the cross section of the capillary will be affected. The desired fineness of the tip of the capillary must also be considered when selecting the diameter of the filaments.
It has been found that the braided filaments of this invention may be comprised of many different materials. By way of example, these filaments may be made of synthetic resinous materials, metals and metal alloys, ceramics, silicates, and the like. It can be appreciated that by selecting the appropriate material, the physical and chemical characteristics of the bonded braid can be varied through a whole spectrum of properties. As different techniques are often required in bonding the filamenis of the braid together when different classes of materials are used, some of the preferred methods for utilizing the major classes of these materials are discussed separately below.
Synthetic resinous filaments If synthetic resinous materials are to be used as the filaments of the braid, they should be selected with regard to the desired physical and chemical properties of the capillary device. For example, if high strength, long wear and chemical resistance are required, filaments comprised of polyamides, polyacetals and polycarbonates may prove most useful. On the other hand, if the primary requisite is a low coeificient of friction, filaments prepared from polyolefins or polytetrafluoroethylene advantageously may be selected.
It has been found that the desirable properties of several different resins can be combined if filaments comprised of different resins are included within the braid. For example, if the capillary device is being prepared for use as a pen tip, a major portion of the filaments in the braid can be comprised of a polyamide to provide for strength and long wear, while a minor portion of the fibers can be comprised of polyethylene to provide for a low coeflicient of friction. Thus, the lubricity of polyethylene can be enjoyed without significantly sacrificing the mechanical properties of a polyamide.
In another modification of this concept, the braid may be comprised in part of soluble filaments such as those comprised of polyvinyl alcohol. Since the polyvinyl alcohol filaments may be leached out of the braid by means of a water bath, the number and size of the capillary openings within the capillary device can be adjusted by the number of leachable filaments used in preparing the braid.
In still another modification of this concept, the braid may include filaments, either natural or synthetic, that will be unaffected by the bonding operation. For example, the braid may be comprised of a mixture of polyamide and cotton filaments. This braid may then be subjected to an intensive bonding operation by placing the braid in a solvent for the polyamide, such as resorcinol. By this means, the polyamide portions of the braid are securely linked together .to impart mechanical strength to the capillary, whereas the cotton filaments will be unaffected by the resorcinol and so will provide the capillary spaces for the transmission of fluids.
After a suitable filament has been selected and braided, the filament must be bonded together, as noted above, to obtain the desired mechanical properties. While it is possible to achieve a bond between the filaments by means of adhesives or by heat, it has been found that finer control can generally be exercised over the bonding operation by using solvents to fuse the resinous fibers together.
As noted above, care must be exercised when bonding the filaments together to avoid excessive blinding of the pores of the braid and the spaces, if any, between the several concentric braids. Preferably, the bonding is restricted only to the points of contact at the intersection of the various filaments. It has been found that this ideal condition can be approached most readily if a solvent is caused to be effective in a relatively short period of time and rapidly absorbed into the filaments. Accordingly, it has been found useful, after the braided structure has been contacted with a solvent, to expose the braid to high temperatures to effect solvation as rapidly as possible. To be effective, these temperatures will frequently approach the melting point of the resinous filaments. After the solvent has been absorbed into the filaments and the bonds have been established, the braid can be immersed in another fluid to remove any excess solvent from the braided structure.
The rapidity with which the solvation takes place will also be affected by the solubility of the filaments in the solvent. As mentioned above, it is generally preferable to cause the solvation to take place as rapidly as possible, and a solvent that has a ready aflinity for the resinous materials should usually be selected.
The penetration of the solvent into the braid will be affected by the viscosity of the solvent. It can be appreciated that a low viscosity solvent or solvent solution will penetrate the interstices of the braid with much greater rapidity than a high viscosity solvent. Thus, it may be useful to adjust the viscosity of the solvent by means of any compatible thixotrope to control the depth of solvation into the braid. For a like reason, the use of a surface active agent to alter surface tension may be desirable.
Another interesting and useful technique by which the degree of open area of the capillaries may be controlled is through the use of interfering materials added to the bonding agent. For example, if water soluble materials are included in the solvent or adhesive, the soluble materials may be removed after the filaments have been bonded together. By so leaching out the soluble materials, a certain amount of open area will result that otherwise might have been blinded by the action of the solvent or adhesive. In some instances, if the interfering materials are porous themselves, it may not be necessary to remove them from the interstices of the braid after the bonding operation has been completed.
By way of illustration, the following example is given as a suitable method of preparing a capillary device from synthetic resinous materials in accordance with this invention, which device is especially adapted for use as a pen tip. This use requires not only that the capillary device feed an adequate amount of writing fluid, but also that it have sufficeint mechanical strength and wear resistance to perform as a writing tip.
Example I A capillary structure comprised of four concentric braids was prepared from fifteen denier nylon fibers and immersed for thirty seconds in a solution of 112 parts by weight of resorcinol, 137 /2 parts by weight water, and 200 parts by weight of sugar. The resorcinol is a good solvent for nylon and sugar probably acts as an interfering material as discussed above. The saturated braid was then removed from the resorcinol solution and twisted to squeeze out excess solution which was then wiped off of the surface of the braid.
The braid was then released from the twist and stretched under about twenty pounds tension and placed in an oven at 400 F. for two minutes. The braid was removed from the oven and quenched in a Water bath and held there for a sufficient length of time to leach out any excess resorcinol and the sugar.
The braid was then removed from the water bath, dried, and cut into one inch lengths. One end of the braid was sharpened to a fine point and the other end of the. braid was connected to a reservoir of writing fluid contained in a pen-like structure.
It was found that the capillary structure prepared in this manner provided an excellent point for the pen, as it Wrote well, provided an adequate flow of ink from the reservoir to the writing surface, did not fray or brush out, and was found to have had only negligible wear after prolonged usage.
Metallic filaments Where the primary requisite of the capillary device is extreme strength, it is particularly useful to weave the braid from metallic filaments. As discussed above with respect to braids made of synthetic resinous filaments, it is here also desirable to bond adjacent filaments to each other primarily at their points of intersection so that the capillary openings within and between the braids will not become blinded. Numerous methods can be utilized to bond these metallic filaments together, and the following are given as being representative.
One of the simpler methods for bonding metallic filaments together is by the use of heat. If the braid is raised to a temperature approaching or slightly exceeding the melting point of the metallic filaments, the filaments will sinter or melt together at their points of contact. The method by which these high temperatures are obtained is not critical, and either an oven can be used or electrical heating methods such as resistance heating or induction heating. When either induction or resistance heating methods are used, it may be preferable to utilize high frequency currents. It is thought unnecessary to give specific temperatures that will accomplish the melting or sintering of metal filaments, as these will vary with each different metal, and it is well within the skill of the art to determine the proper temperature with respect to any given metal.
When induction heating is used, the braid may be subjected to the influence of an energized induction coil while the braid is submerged in a water bath. Since the water will fill the capillary spaces of the braid, the filaments will be cooled where they are not in contact with each other, but not at those points where they touch and water is partially excluded. This will facilitate securing a bond by melting or sintering at the points of contact of the metallic filaments while reducing the danger of overheating the rest of the braid and blinding the capillary spaces.
As is the case with filaments comprised of synthetic resinous materials, metallic filaments can be bonded together by means of adhesive. In one of these methods, an adhesive can be applied to the filaments prior to the braiding operation. By another method, the braid may first be woven and then contacted with the adhesive. In either case, it is convenient to utilize adhesives that can be applied from solution so that careful control over the thickness of the coating and/or the penetration of the adhesive into the braid can be obtained. One particularly useful class of adhesives are the heat reactive resinous materials such as epoxies and phenolics.
And yet another method whereby the filaments of the braid may be bonded together at their intersections is by means of electrolytic deposition of metals from solutions onto the braid. By controlling the thickness of the deposition, both the strength of the braid and the size of the capillary spaces may be controlled. This enables, for example, the use of a comparatively open braid since the capillaries of the braid can be filled in to any desired extent by controlling the rate and time of the metallic deposition process.
It should be understood that it is within the scope of this invention to use electrolytic deposition processes either with or without an externally imposed EMF. As it may be diflicult to adjust the current density throughout the entire cross sectional area of the braid, particularly if multiple concentric braids are used, more uniform deposition of the metal may be obtained if an external EMF is not imposed.
These metallic deposition processes may also be utilized to bond non-metallic filaments if a conductive surface is first provided over the filaments. For example, coatings of graphite or conductive polymeric materials may be applied from solution or coatings of metals may be applied as by vacuum metalization of vapor phase deposition.
The combination of several of the above techniques may prove useful. For example, the degree of bonding can be improved by subjecting the braided filaments to heat sintering temperatures after an electrolytic deposition step.
In addition to the extreme stiffness that can be obtained by using metal braids, these braids are desirable since they can be ground to form smooth tips as would be required in preparing writing instruments. In order to prevent blinding of the capillaries of the tip during grinding operations, it may be desirable to include certain solid materials within the braid. If such solid materials are included, they must, of course, be capable of being removed from the braid after the grinding operation. For this reason, solid materials should be selected that are soluble, such as salts, or otherwise removable as by melting below the sintering point of the metal filaments.
Cold drawing techniques may also be used to bond the filaments of a metal braid together. When using this method, the metal braid is drawn through a reducing die that will reduce the diameter of the braid and simultaneously cause the filaments of the braid to flow and bond together at their points of contact due to the heat and pressure that is developed.
Glass filaments The versatility of the braids of this invention is further illustrated by the use of glass filaments to form the braid. When filaments of fiberglass are woven into braid and then bonded at their points of intersection in accordance with the teachings of this invention, a rigid capillary device is produced that can be polished at its end to produce a smooth tip such as may serve as the tip of a writing instrument.
The techniques that may be utilized to bond glass filaments together are quite similar to those discussed above with respect to metals. First, excellent adhesion between the filaments can be obtained by heating the braid to glass sintering temperatures. This can be done in an oven or by means of an open flame. Also, the filaments of the braid may be adhered together by utilizing solvents. As mentioned with respect to metal filaments, these adhesives are preferably applied from solution and this may be done either before or after the filaments have been woven into the form of a braid.
As was mentioned above in regard to metal filaments, it may be difficult to grind a point at the end of a capillary device comprised of glass filaments due to the fact that the grinding operation may melt or smear the ends of the filaments together and cause them to blind the capillaries at the tip. In addition to cooling the tip while it is being ground or polished, it may be useful to include a solid soluble substance within the capillaries of the braid that will act as a physical impediment to prevent the capillaries from being closed. As an example of this technique, the braided structure may be immersed in a high concentration salt bath and then dried. The salt that is so deposited within the capillaries of the braid may be readily removed after the grinding operation as by leaching in hot water. Also, it may be desirable to form a smooth tip on the end of a glass braid by utilizing flame polishing techniques.
In addition to the adhesives such as epoxies and phenolics that might be used in bonding glass together, certain other substances may be selected that chemically react with the glass to cause bonding as by cross linking. For example, siloxanes, colloidal silica, diisocyanates and organic titanates are of this general type.
It should be mentioned that fiberglass filaments, as are conventionally obtained in the marketplace, are usually coated with sizings and the like. Ordinarily, this is required to enable braiding or otherwise working with the filaments without cracking them. These sizings, depending upon their composition, may adversely affect the bonding of the filaments together either by heat or with adhesives, and it may be necessary to remove them before the bonding operation.
Still another technique that may be utilized in forming a smooth tip, which is applicable to glass, resinous or metallic filaments, is etch polishing. After a tip has been roughly formed, it may be inserted in a reagent that is effective to dissolve the material of which the braid is comprised. As is well known, etch polishing will cause the comparatively small irregular portions to be dissolved away first, thus leaving a comparatively smooth tip free of irregular surface projections.
Example II A capillary device suitable for use as a writing tip was prepared in the following manner. A braid comprised of glass filaments and having four concentric layers was woven. The braided structure was then immersed in an epoxy solution comprised of the following:
Parts by weight Epoxy resin 2O Hardener 20 Methyl ethyl ketone 60 (The epoxy and epoxy hardener that were used were purchased in the marketplace under the trade name Duro- Epox-E which is a two component, room curing epoxy cement.)
The concentric braided fiberglass structure was immersed in this resin solution and gently squeezed to insure penetration of the solution into the interstices of the braid. It was then removed from the solution, stretched, and the outside of the braid wiped free from excess solution. The impregnated braid was then placed in an oven at 350 F. for about one hour and removed. A tip was formed by cutting the braid with a razor blade and polishing the tip lightly with emery cloth. The tip was then immersed momentarily in the same solution and cured once more in the oven for about 15 minutes at 450 F. After the tip was removed from the oven, it was lightly polished again with emery cloth and then inserted in a pen holder with the pointed end protruding from the holder and the other end in contact with a reservoir of ink contained within the holder. This produced a very rigid, yet well flowing marking device that wrote quite well with a solid line. The tip was sufficiently stiff so that five or six legible carbon copies could be made at one time.
In the above description of this invention, particular emphasis has been placed on braids that are comprised of filaments of synthetic resinous materials, metals or glass. It should be understood that it is within the scope of this invention to use other materials that are available in the form of filaments that are capable of being braided together and that can be bonded together at their intersections as described above.
It is also apparent that useful combinations of these various materials may be used. For example, a few strands of metal may be included within a braid comprised substantially of synthetic resinous filaments. By this means, the metal filaments will add strength to the plastic filaments while the smoothness and lubricity of the resinous filaments will be preserved. Bonding can be accomplished by utilizing a heat sensitive adhesive or primer that is applied to the metal filaments that will enable, upon activation of the adhesive, bonding the various filaments to each other at points of contact.
Viewed from the opposite viewpoint, it is sometimes desirable to prepare a braid in which the majority of the filaments are comprised of a metal and only a minor portion of synthetic resinous filaments are used. These can be adhered together as described above and will enable the manufacture of a high strength capillary device with a built-in lubricant in the form of the resinous filaments. For example, the metal filaments may be comprised of high strength metals such as stainless steel, and the plastic filaments may be comprised of polyethylene or polytetrafiuoroethylene.
Also, it can be appreciated that for certain specialized applications it might be desirable to use mixed braids comprised of metal and glass, plastics and glass, and even plastic, glass and metal.
It must be understood that in the above description of this invention, the term filaments is not restricted to monofilaments. Rather, it is intended that this term also include bundles of smaller filaments such as staple and thread.
From the foregoing, it can be appreciated that there are many variables that must be taken into account when preparing capillary devices. On the whole, there is no single criterion that might be placed on the selection of the proper set of conditions or materials to be used. In each instance these must be determined in view of the intended use, the construction of the braid, whether both axial and radial flow are desired or required, the distance the liquids must be transferred through the capillary device, the desired physical characteristics of the device, such as stiffness, strength and rate of feed, etc. However, it is believed that these conditions can readily be determined by one skilled in the art in the light of the foregoing exposition.
1. A capillary device of the class described comprising filaments woven into a braided structure, which filaments are bonded to each other primarily at the points where they intersect adjacent filaments to form a rigid structure whereby the device is capable of feeding liquids in both an axial and radial direction.
2. A capillary device according to claim 1 in which said braided structure is comprised of a plurality of concentric braids.
3. A capillary device according to claim 1 in which said filaments are selected from a class consisting of metals, glass, ceramics, synthetic resins, and combinations thereof.
4. A capillary device according to claim 3 in which said synthetic resin is a polyamide.
5. A capillary device according to claim 1 in which one of said ends thereof communicates with a liquid reservoir.
6. A capillary device according to claim 5 in which the other one of said ends is adapted to apply liquids to a surface.
7. A capillary device according to claim 1 in which said filaments are of cross sections other than circular.
8. A capillary device according to claim 7 in which said filaments are multi-lobal.
9. A method for the preparation of a capillary device comprising the steps of weaving a plurality of filaments together into a braid and bonding adjacent filaments in said braid to each other primarily at their points of intersection to produce a device capable of feeding liquids in both an axial and radial direction.
10. A method according to claim 9 in which said filaments are bonded by heat.
11. A method according to claim 9 in which said filaments are bonded by an adhesive.
12. A method according to claim 11 in which said bonding is achieved by means of a solvent.
13. A method according to claim 12 in which said braid is first contacted with said solvent and is then exposed to temperatures approaching the melting point of such fiber.
14. A method according to claim 12 in which said filaments are comprised of a polyamide.
15. A method according to claim 9 in which said filaments are braided around a central core,
16. A method according to claim 15 in which said core is removed from said braid after said bonding.
17. A method according to claim 16 in which said core is comprised of a soluble material.
18. A method according to claim 9 in which said filaments are comprised of synthetic resinous materials.
19. A method for preparing a capillary device comprising the steps of braiding a plurality of polyamide filaments into a plurality of concentric braids; bonding said braided polyamide filaments to adjacent filaments primarily at their points of intersection by contacting said braided structure with a solvent for said polyamide and exposing said braid to elevated temperatures approaching the melting point of the polyamide in order to cause said solvent to be absorbed, at least in part, into said polyamide filaments to produce a device capable of feeding liquids in both an axial and radial direction.
20. A method according to claim 19 in which said solvent is resorcinol.
21. A method according to claim 19 in which said solvent includes an interfering agent.
22. A method according to claim 21 in which said interfering agent is sugar.
23. A method according to claim 21 in which said interfering agent is caprolactam.
24. A method according to claim 19 in which said temperature is about 400 F.
25. A method according to claim 9 in which a portion of the filaments of said braid is comprised of materials that may be leached out of the braid after said bonding operation.
26. A method according to claim 9 in which said filaments are comprised of metal.
27. A method according to claim 26 in which said metal filaments are bonded together by means of depositing controlled quantities of metal thereon.
28. A method according to claim 27 in which said deposition is an electrolytic deposition method.
29. A method according to claim 9 in which said filaments are comprised of glass fibers.
30. A method according to claim 29 in which said filaments are bonded together by means of an adhesive.
31. A method according to claim 30 in which said filaments are bonded together by means of heat.
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