US2253089A - Spinning apparatus and method - Google Patents

Description

. 1941- i R. NYDEGGER 2,253,089

SPINNING APPARATUS AND METHOD Filed Feb. 18, 1939 3 Shasta-Sheet l 20/4/20 INVENTIORI V 1 ATTORNEY 9, R. R. N YDEGG ER I 2,253,089

' SPINNING APPARATUS AND METHOD Filed Feb. 18, 1939 3 Sheets-Sheet 2 4 I g Q INVENTOR 1 Rolaha R. Vgde if!) ATTORNEY Aug. 19, 1941.

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R. R'. NYDEGGER Filed'Feb. 18. 1959 SPINNING APPARATUS AND METHOD 3 Sheets-Sheet '3 'INVENTOR ATTORNEY Patented Aug. 19, 1941 SPINNING mans'ros sun Manson Roland Roswell Nydcss' r, Wilmington, net, as-

signor to E. I. du Pont de Nemonrs & Company, Wilmington, not, a corporation of Delaware Application February is, loss, 88] no. 251,105

(Cl. Is-s) Claims.

This invention relates to improvements in method and apparatus for the spinning of filaments. More-particularly, it relates to an improved method and apparatus for the spinning of such filaments from molten filament-forming compositions composed largely of organic compounds.

This application is a continuation-in-part of my application, SerialNo. 204,511 filed April 27, 1938.

Such filaments, and filament-forming compositions from which the filaments are formed, will hereafter be referred to as organic filaments" or organic filament-forming compositions.

Heretofore. in the spinning of filaments from molten organic filament-forming compositions, it was considered necessary to first melt the filament-forming composition in a suitable chamber and then force the molten mass by means of gas pressure or by means of a pump, through a suitable spinneret, or the like. Such prior art methods were suitable for use in the spinning of molten organic filament-forming compositions which were not subject to deterioration or decomposition when exposed to a melting tempera-- ture for an extended period of time. 7

In the melt spinning of organic filaments from solid materials, which are subject to decomposition at high temperatures, prior art methods, which involve the maintaining of the molten materials at high temperatures for extended periods of time, are objectionable.

It is an object of the present invention to provide an improved method and apparatus for the displacement spinning of filaments from molten organic filament-forming compositions.

It is a further object of this invention to provide an improved method and apparatus for the production of organic filaments from melts with a minimum exposure of the melts to high temperatures.

It is another object of this invention to provide a method and apparatus for the displacement spinning of filaments from molten organic filament-forming compositions whereby the spinning operation can be readily carried out in a continuous manner.

It is a further object of this invention to provide a method and apparatus for the displacement spinning of filaments from molten organic filament-forming compositions whereby the continuous spinning of the products can be carried out more uniformly over extended periods of time.

Other objects of .the invention will appear hereinafter.

against a surface having an elevated temperature to melt the solid, said melted composition lecting said filaments in any desired manner. I

Preferably the solid, in the form of a uniformly shaped, compact mass, is forced through an aperture into a melting chamber provided with a melting surface.

In order to more clearly define the present invention, reference is made to the following de-, tailed description taken in connection with the accompanying illustrations of one modification of apparatus suitable for use in accordance with the present invention, and in which:

Figure 1 is a side elevational view, with parts shown in section, of amelting device, solid filament-forming material, sealing ring and spinnere Figure 2 is a side elevational view of an apparatus suitable for use in continuously feeding rods of filament-forming material into a melting de- Figure 3 is a sectional view of one of feeding clamps.

Figure 4 is a sectional view taken along the line 4-4 of Figure 2.

Figure 5 is a sectional view taken along the the rodline 5-8 of Figure 2.

The objects of the invention may be accomplished, in general, by forcing a solidcomposed of an organic filament-forming composition Figure 6 is a side elevational view taken along line 0-8 of Figure 5 with parts shown in section of a portion of a rod-feeding clamp.

Figure 7 is a side elevational view, with parts shown in section, of another modification of the apparatus suitable for continuously feeding molten filament-forming material to a spinneret.

Referring to the drawings, reference numeral i designates a uniformly shaped and compact rod of a solid filament-forming material which is continuously forced at a constant speed through the sealing ring 3' into the melting chamber 2 by means of a constant speed, pressing member i. The member 4 may be driven in any desired manner. As the rod I is forced into the melting chamber, it contacts the heated inner wall 5 of the chamber. The temperature of wall 5 is maintained somewhat above the melting point of the rod by means of heating units 6 which may be heated fluid coils; electric heating elements or any other desired heating means. The heating units 6 are enclosed by insulation I. The solid rod of filament-forming material melts at a uniform rate as it is forced against the heating surface of wall 5 and the molten material is in turn forced through channel 8 to spinneret 9 from which it issues as filaments l0 which are drawn away at a uniform speed and wound on a wind-up bobbin or the like (not shown). It

- has been found advantageous to pass the molten it is extruded through the spinneret. It has furthermore been found desirable to insulate the sealing ring 3 from the heated chamber 2 by means of insulation [2 and, if necessary, by the additional means of-cooling coils, or the like, l3, thus maintainingthe sealing ring 3 below the melting point of the rod of filamentdorming material. If desired, the erosion of the bottom plate of insulation can be substantially eliminated by means of a metal liner- I4.

It is essential for the smooth operation of the process, and for the production of filaments and yarn of uniform denier, that the rod fed to the displacement spinning unit be uniform in diameter and density. This is necessary to secure the proper seal at the sealing ring and a uniform flow of the molten material to the spinneret. Some filament-forming materials capable of being spun from melt are somewhat elastic so that the diameter of th rod, when composed of such material, should be slightly greater than the diameter of the sealing ring in order that a tight seal maybe obtained. In many cases, however,

the rod expands sufficiently by reason of the heat transmitted to the rod from the melt chamber so that the initial rod can be made of the same diameter or even of slightly smaller diameter than that of the sealing ring. It is advantageous to have the sealing ring slightly tapered as shown in the drawings withthe larger end outermost.

If desired, the end of the rod which is to be in troduced into the ring may also be tapered.

The rods to be fed into the spinning unit can be prepared by any suitable means; e. g., casting, extrusion or machining. The rod should be bubble free, have a uniform density, size and shape, and be as smooth as possible. If desired, it may be covered with a lubricant; e. g., a high boiling or polymeric hydrocarbon.

Referring to the continuous feeding mechanism shown 'in Figures 2-6, reference numeral 20 designates a supporting frame which will be fixedly'connected relative to a melting chamber such as is described with reference to Figure. 1 of the drawings. A pair of collars 22 is rotatably mounted in supporting frame 20. Each of the collars 22 has a worm-driven pinion 24 keyed thereto. The pinions 24 are positioned in aligned is positioned in housing 40. The gears 46 are arranged to mesh with worm pinions 38, so that upon rotation of shaft 44 th worm pinions will be simultaneously and synchronously rotated. The shaft 44 is provided with a square end 46 whereby to connect to 'said shaft a hand crank having a similarly shaped opening.

The operation of the continuous feeding mechanism will be as follows: A rod I of the filamentforming material will be positioned in a rodfeeding clamp 28 and the clamping elements 36 and 32 tightened by means of screws 34. The lower end of the rod will be positioned in the sealing ring 3. The worm pinions 24 will be synchronously rotated, thereby causing shafts 26 to be rotated. The rotation of shafts 26 in a counter-clockwise direction will cause a lowering of the rod l and rod-feeding clamp 28. After the rod I has been forced into the melting chamber 2 a substantial distance and when the lowermost rod-feeding clamp 28' approaches the top surface of the melting chamber, a second rod la is positioned smoothly against the top of rod I without overlapping. A second rod-feeding clamp is fastened to the top of rod la. Then a hand crank (not shown) is positioned on the end 4! of shaft 44. The cranl: is turned clockwise to lower the upper clamp 28 until the upper rod la is pressed tightly against rod I. At this point the two rod-feeding clamps will be simultaneously moved downwardly by the shafts 26 at the same speed.

The lower rod-feeding clamp 26 can now be released by loosening screws 34, and by attaching the hand crank thereto and turning the same counter-clockwise, th lower clamp 26 can be moved upwardly along the shafts 26 until it touches the upper clamp 28. This cycle can be repeated indefinitely.

Figure 7 illustrates another form of apparatus for the continuous melt spinning, for long D8? riods, without interruption. This apparatus com-f prises two or more rod-feeding mechanisms, sealrelationship to each other so that they may be simultaneously and synchronously driven by a single worm gear or two worm gears mounted on a single drive shaft in a manner well known. The collars 22 are also keyed to their respective threaded shafts 26 whereby to rotate the latter upon rotation of the worm pinions 24. threaded shafts 26 may, if desired, be rotatably The.

connected to the top 'of melt-ing chamber 2 of Figur 1.

One or more rod-feeding clamps 26 are positioned on the threaded shafts 26 so that they may be moved downwardly toward the melting chamber 2 upon rotation of the shafts 26 in a counter-clockwise direction. The rod-feeding clamps comprise clamping frames 30 and 32 which cooperate with the aid of screws 34 to firmly hold a rod of filament-forming material therebetween. Sleeves 36, having internal threads cooperable with the threads of shafts 26, are rotatably mounted in clamping frame 30. Worm pinions 3a are fastened to the tops of sleeves 36; the pinions 38, however, are not internally threaded and are adapted to clear the threads of shafts 26. A shaft housing 40 is attached to frame 30 by means of screws 42. A shaft 44 provided with a pair of worm gears 46 ing rings, melting surfaces, etc. in communication with the spinneret. As in Figure 1, reference numeral l designates a uniformly shaped and compact rod of solid filament-forming material which is forced through the sealing ring 3into the melting chamber 2 by means of a constant speed, pressing member 4. The member 4 may be driven in any desired manner. As the rod l is forced into the melting chamber, it contacts the heated inner wall 6 which is maintained at a temperature above the melting point of the rod by the heating units 6. The reference numerals I, 3', 4', etc., designate an identical rod, press ing member, sealing ring, etc., respectively mounted in the samemanner as that designated by I, 3, 4, etc., and in the same melt chamber 2. The solid rods of filament-forming material melt at a uniform rate as they are forced against the heating surfaces of the walls 5 and 5' and the molten material is in turn forced into the channels 48 and respectively which are provided with the valves 5| and 62 respectively, and thence through the passage 8'to the spinneret 9 from which it issues as filaments III which are drawn away and collected in ,an orderly manner. Reference numeral l2 designates a member insulating the sealing ring from the heated chamber 2, l3 designates cooling coils as additional means for maintaining the temperature of the sealing ring below the melting point of the rod andi4 designates a metal liner to prevent erosion of neously from the duplicate assemblies. multaneously feeding rods of filament-forming In the operation of this modification, the rod of solid fllament-forming-material I is used to spin filaments in the manner previously described. As the rod l becomes nearly exhausted, the rod I is brought into, contact with the heatlng surface if and when melting at a uniform rate is attained the pressure on it is increased and that on the rod I is decreased proportionally until the transfer is completed. This transfer may be facilitated by the use of the valves SI and. "The valve is closed and the nearly exhausted rod I is then replaced with a fresh rod which when-the rod I' is nearly exhausted, is

brought into operation in the same manner as that described for transfer from rod I to I'. If desired conduits 54 and 56 with valves.58'and 60 respectively may be provided for removing melted material during that period when a uniform melting rate is being reached, prior to changeover from one melting unit to the other.

vB re titio -Qt. ih 9 a t i m ss to supply @molten material to the spinneret at a uniform rate continuously for long periods. This transfer ma'ybe facilitated by the use of rod pressure mechanisms synchronized. with, or directly connected to, valve opening and closing mechanisms so as to accomplish the changeover automatically. v v

While this modification of the invention is illustrated by the use of rods of the same diameter,'it is not so limited since it is only necessary to displace a uniform quantity of molten material which can be accomplished in the case of different diameter rods by feeding at different linear speeds. Likewise, the two feeding and-melting mechanisms may be mounted in separate melt chambers, or a larger number of them mounted in the same melt chamber. It is also possible .to use a single auxiliary feeding and melting mechanism for a plurality of spinnerets since the time required to replace the exhausted rod is usually much less than the time in which it is consumed. Suitable, valves and'synchronizing mechanisms may be used to insure that the molten material is fed to the spinneret at a uniform rate.

If desired, the apparatus shown in Figure 7 may be used to feed molten material simulta- By-siin accordance with ,the present invention. These 3 polyamides are of two types: those obtainable from monoaminomonocarboxylic acids or their amide-forming derivatives, including caprolactam, and those obtainable from the reaction of suitable diamines with suitable dibasic carboxylic acids or their amide-forming derivatives. The polyamides of the two types are more fully described in U. S. Patents No. 2,071,253 and No. 2,130,948 respectively. As examples of such polyamides might be mentioned polytetramethyh ene sebacamide,. polyhexamethylene-suberamide,

polyhexamethylene sebacamide, polydecamethylene adipamide, and thepolyamide derived from' fi-"amino-caproicflgacid. Interpolyamides an d mixtures of polyamides can also be used in this invention. v

These polymers unlike most previously .described filament-forming materials, are sufflciently stable to permit their spinning into fllamerits and the like directly from melt; i. e., without the use of solvents or. plasticizing agents.

The methods previouslydescribed for spinning such materials from melt consist in melting the polymer in a suitable chamber and extruding it therefrom through a suitable aperture or spinneret by means of gas pressure or by means of a pump; e. g., a constant deliverygear pump. These processes have certain disadvantages. If

gas pressure is used, 'it is difllcult to maintain constant delivery even though the gas pressure be kept constant because slow dirt collection 'in the spinneret packsincreases the back pressure which results in a decrease the spinneret output and in the denier of the spun material. A diflicultywith the use of a. spinning pump is that exposure of the moving parts of the pump to the 'high temperature molten filament-forming material res'ults in short pump life. More importantly, the .expansion of the pump parts at the high temperature causes pump leakage and serious variations in denier. A disadvantage of both methods is that the filament-forming material must be heated considerably above its melting point to securesmooth spinning. This frequently resultsin thermal decomposition of the filament-forming material with the forma-v tion of gaseous or other undesirable by-products. Furthermore, a considerable reservoir .of the illament-forming material must be kept in the molten state to maintain uniform spinning which further promotes thermal decomposition. These isadvantages are overcome by the process and apparatus of the present invention.

The process will now be described more specifically with reference to polyhexamethylene adipamide, a fiber-forming linear condensation polyamide derived from the condensation polymerization of hexamethylene diamine and adipic acid. I

Example truding molten polymer having an intrinsic viscosity of 0.9 and a melting point of about 263 C. from an-autoclaveunder -lb. oxygen-free nitrogen pressure into an electrically heated casting tube against a downward moving piston, and cooling the tube while maintaining the same under pressure; The smooth rcd thus formed was readily removed from the tube by means of the piston. This rod was then machined to a perfect cylinder and fed into a displacement spinning unit of the type shown in the drawing, mounted in an Olsen test ng machine where advantage could be taken of both the uniform feed and the balance to measure the pressures applied to the mechanism. The "rod wasforced through thesealing ring and against the melting surface of the melting chamber under a total pressure of 2,500 lbs., of which approximately 400 lbs. represents the resistance through the sealing ring. The melting surfaces were maincontained 30 openings, each 0.0088 of an inch in diameter. Under these conditions, SO-filament yarn of fairly uniform denier (discounting thatspunduring the first few minutes) was spun at a rate of about 13.5 grams per minute. The yam was wound up on a bobbin at a rate of 2,000 feet per minute.

Although the foregoing example illustrates the invention with specific reference to a synthetic polyamide, it will be apparent that the process can be applied to other materials. The invention is applicable to the spinning of any organic filament-forming material which is capable of being spun from melt. As examples of such filaplasticised can also be spun by this method. If

the mechanical characteristics of the rod are such as to require it, the rod may be supported by a reinforcing cylinder, in. which case the pressing member will ride. in thecylinder, and the latter may, in such a modification, function in the capacity of a sealing ring.

The filament-forming material used in the process of this invention may contain modifying s,ass,oso

the above process of forcing a solid rod of filament-forming material through a melting chamber, it is possible to extrude continuously for long periods of time with exceptionally uniform results. Greater uniformity of filament denier is obtainable since a specific volume of filamentforming material is displaced, regardless of the increase in resistance resulting from accumulation of dirt on the screen'pack.

(7) There will be a reduction of surface dirt on the filament-forming material because of the more favorable ratio of area to volume of the raw material. In other methods, the filament-formmodifications of the above process and apparatus agents; e. g., luster-modifying agents, plasticizers, pigments, dyes, antioxidants, resins, etc.

The example illustrates the application of this invention to the preparation of a yarn. on sub- Jecting this yarn to cold drawing, it is converted into a yarn of smaller denier and improved properties, which is very useful in making fabrics. It is within the scope of this invention to make larger diameter filaments; e. g., those of bristle, mohair or horsehair size. These large filaments can be spun from multiple hole spinnerets or from single hole spinnerets. Likewise, a plurality of spinnerets may be fed by a single melting assembly. Ribbons, foils, sheets, etc. can also be prepared by displacement spinning. For this purpou it is usually desirable to extrude the filament-forming material through a slit orifice and/or collect the product on a suitable forming roller or rollers to secure the proper uniformity.-

By practice in accordance with the presentinvention, it is possible to extrude a filamentforming material at an exceptionally constant and uniform rate. Therefore, by'withdrawing the extruded filaments at a uniform rate, it is possible to obtain filaments and yarns'of very uniform denier. The process has the following advantages over previously described methods of melt spinning:

(1) Minimum exposure of the filament-forming material to high temperatures.

(2) Complete elimination of a gas blanketing agent in the melt chamber.

(3) Melt chamber is self-cleaning.

(4) Less screen packing is necessary, since the danger of small pieces of unmelted material in the molten mass is minimized.

(5) By forcing a uniformly shaped, compact rod of a filament-forming material through an aperture, such as a sealing ring, into a melting chamber, the spinning process can be made continuous by following one rod with another without stopp the spinning operation.

can be made without departing from the nature and spirit of the invention, it is to be understood that the above description is not to be limited except as set forth in the appended claims.

I claim:

1. In an apparatus for the melting of unifon nly shaped solid rods of organic filamentforming compositions and the forming of filaments from the melted compositions, a plurality of spaced melting surfaces, a sealing ring connected to each of said melting surfaces, said sealing rings serving as entrances for said rods to said respective melting surfaces, at least a section of each of said sealing rings having an internal dimens on smaller than the cross-sectional dimension of said rods, positively driven means for forcing said rods through one of said sealing rings at a uniform rate against the corresponding melting surfaces, conduit means from each of said melting surfaces to a common outlet, and a shut-oi! means in each of said conduit means.

2. In an apparatus for the melting of uniformly shaped solid rods of organic filamentforming compositions and the forming of filaments from the melted compositions, a plurality of spaced melting surfaces, a sealing ring connected to each of said melting surfaces, said sealing rings serving as entrances for said rods to said respective melting surfaces, at least a section of each of said sealing rings having an internal dimension smaller than the cross-sectional dimension of said rods, positively driven means for forcing said rods through one of said sealing rings at a uniform rate against the corresponding melting surfaces, an extrusion orifice, conduit means from each of said melting surfaces to said extrusion orifice, and a shutofi means in each of said conduit means.

3. In an apparatus for the melting of uniformly shaped solid rods of organic filamentforming compositions and the forming of filaments from the melted compositions, a plurality of spaced melting surfaces, a sealing ring connected to each of said melting surfaces, said sealing rings serving as entrances for said rods to said respective melting surfaces, at least a section of each of said sealing rings having an internal dimension smaller than the cross-sectional dimension of said rods, positively driven means for forcing said rods through one of said sealing rings at a uniform rate against the corresponding melting surfaces, an extrusion ori- (8) By combining a screen pack or filter with 7 fice, conduit means from each of said melting surfaces to said extrusion orifice, and a shut-off means in each of said conduit means, and means between said melting surfaces and said extrusion orifice for withdrawing molten composition from each of said melting surfaces;

4. In an apparatus for the forming of filamentous structures from melts of organic filament-forming compositions, a melting chamher, a sealing ring connected to said melting chamber, said sealing ring having walls converging inwardly towards the interior of said chamber, a spinneret in said chamber, and means for forcing a uniformly shaped, solid mass of the filament-forming composition through said ring into said chamber whereby to melt said material and force the molten material through said spinnere 5. In an apparatus for the forming of filamentous structures from melts of organic fllament-forming compositions, a melting chamber, a sealing ring connected to said chamber, a sp'inneret in said chamber, means for forcing a uniformly shaped, solid mass of the filamentforming material through said ring into said chamber whereby to melt "said material and force the molten material through said spinneret, anda filtering means in said chamber between said seaIi-ngring and said spinneret.

6. The method of forming filaments from melts of organic filament-forming compositions of crystalline character which comprises forcing a solid, uniformly shaped r'od composed of said composition through an aperture of smaller cross-sectional dimension than said rod and against the solid surface of an element having an elevated temperature to melt only that portion of the rod adjacent said surface, and forcing said melted composition from said surface and through an opening of the desired shape by pressure of the oncoming solid rod.

'7. The method of forming filaments from melts of synthetic linear polymers 'which comprises forcing asolid, uniformly shaped rod composed of said polymer through an. aperture of smaller cross-sectional dimension than said rod and against the solid surface of an element having an elevated temperature to melt only that portion of the rod adjacent saidsurface, and forcing said melted polymer from said surface and through an opening of the desired shape by pressure of the oncoming solid rod,

8. The method of forming filaments from melts of organic filament-forming compositions of crystalline character which comprises forcing a solid, uniformly shaped rod composed of said composition through an aperture of smaller cross-sectional dimension than said rod and against the surface of an element having an elevated temperature to melt only that portion of the rod adjacent said surface, and forcing said melted composition through a filtering medium and through an opening of the desired shape by pressure of the oncoming solid rod.

9. The method of forming filaments from melts of organic filament-forming compositions of c'rystalline character which comprises forcing at a substantially constant, uniform rate; a

element having an elevated temperature to melt face, and forcing saidmelted composition from said surface and through an opening of the desired shape by pressure of the oncoming solid 10. In an apparatus for the melting of a series of uniformly shaped solid pods of organic filameat-forming compositions and the forming of filaments from the melted compositions, a melting chamber having a solid melting surface therein, a sealing ring connected to said melting' chamber, at least a section. of said sealing ring having an internal dimension smaller than the cross-sectional dimension of said rods, and positively driven means for forcing, at a substantially constant, uniform rate, said series of rods through said sealing ring and against said melting surface.

11. In an apparatus for the melting of a series of uniformly shaped solid rods of organic filament-forming compositions and the forming of filaments from the melted compositions, a melting chamber having a solid melting surface therein, a sealing ring connected to said melting chamber, at least a section of said sealing ring having an internal dimension smaller than the cross-sectional dimension of said rods,-a spinneret in said chamber, a plurality of ,members adapted to be clamped on said rods, and means for moving said members toward said. melting surface at a constant, uniform rate for forcing said series of rods through said sealing mg and against said melting surface and forcing the melted composition through said spinneret.

12. In an apparatus for the melting of a series of uniformly shaped solid rods of organic filament-forming compositions and the forming of filaments from the melted compositions, a melting chamber having a solid melting surface therein, a sealing ring connected to said melting chamber, at least a section of said sealing ring having an internal dimension smaller than the cross-sectional dimension of said rods, and means for continuously forcing a successive series of rods at a substantially constant, uniform rate through said sealing ring and against said melting surface, said means comprising a plurality of rod clamping members, means for forcing said members toward said melting surface, and means for shifting said members along said forcing means.

13. In an apparatus for the melting of a series of uniformly shaped solid rods of organic filament-fomiing compositions and the forming of filaments from the melted compositions, a melting chamber having a solid melting surface therein, a sealing ring connected to said melting chamber, at least a section of said sealing ring having an internal dimension smaller than the cross-sectional dimension of said rods, a series of positively driven rod clamping members, screw means for continuously forcing said rod clamping members toward said melting surface, and means for shifting said rod clamping members along said screw means, whereby to force a successive series of rods at a substantially constant, uniform rate through said sealing ring and against said melting surface.

ROLAND ROSWELL NYDEGGER.

Only that portion of the rods adjacent said sur- CERTIFICATE OF CORRECTION.

; taunt No. 2,255,089. August 19, 19M.

" ROLAND ROSWELL NXDEGGER.

I It is hereby certified that error appears in the printed snecification of the above nuinbered patent requiring correctionas follows: Page 11., second column; lines 58, 55 and 72, claims 1, 2, and 3 respectively, strike out 'the words "one of"; page 5, second column, line 7, claim 10, for "pods read --rods-- and that the said Letters Patent should be read with this correction therein that the sememay conform to the record of the case in the Patent o'riie.

Signed and sealed this 7th day of October, A. D. 19!}1.

Henry Van'Arsdale, (Seal) Acting Commissioner of Patents.

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