US2756915A

US2756915A - Method of charging vessels, utilizing vacuum and centrifugal force

Info

Publication number: US2756915A
Application number: US347498A
Authority: US
Inventors: Joseph L Ritter
Original assignee: WA Sheaffer Pen Co
Current assignee: WA Sheaffer Pen Co
Priority date: 1953-04-08
Filing date: 1953-04-08
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

July 31, 1956 J. L. RITTER METHOD OF CHARGI 2,756,915 NG VESSELS, UTILIZING VACUUM AND CENTRIFUGAL FORCE Filed April 8, 1953 IN V EN TOR.

United States Patent METHOD OF CHARGING VESSEELS, UTILIZING VACUUM AND CENTRKFUGAL FORCE Joseph L. Ritter, Fort Madison, Iowa, assignor to W. A.

Sheatfer Pen Company, Fort Madison, Iowa, :1 corporation of Delaware Application April 8, 1953, Serial No. 347,498

1 Claim. (Cl. 226-63) This invention relates to an improved method and apparatus for charging vessels and more particularly to an improved method and apparatus for charging vessels with a viscous fluid medium and expelling entrapped air therefrom.

It is an important object of this invention to provide an improved method and apparatus for charging vessels With a viscous fluid medium and removing substantially all of the air from such vessels.

When filling an elongated vessel open at one end, it is necessary to charge the vessel with the fluid medium from the open end and concurrently remove the air in the vessel through the same opening. When handling low viscosity liquids these two objects can be concurrently accomplished as the weight of the liquid column is suflicient to overcome the viscous forces Within the liquid and thus force bubbles of entrapped air to rise through the liquid to the top of the vessel, thus providing a cavity completely occupied by the fluid and free of entrapped air.

In viscous fluid mediums, however, the viscosity of the fluid is high relative to its weight, and thus the weight of the fluid is not suflicient to cause the fluid to displace the. entrapped air. Thus air bubbles have a tendency to remain within the vessel when filled by the methods heretofore known. This phenomenon is especially apparent in charging ball point pen cartridges with a viscous writing fluid. The writing fluid customarily used in ball point pens has a high viscosity and is stored within a long, thin, cylindrical cartridge which is contained Within the pen barrel. If small bubbles of entrapped air exist within the cartridge the operation of theball point pen is detrimentally aifected. As the pen is used in Writing, the bubbles entrapped within the fluid move with the fluid to the tip area and eventually surround the ball point. At such a time in the writing operation a discontinuity in the written line will occur. Often the writ ing medium remaining within the reservoir behind the entrapped air cannot be utilized because of a loss of continuity of the fluid column and consequentloss of drawing force which is produced Within the column during writing.

Therefore, it is a further object of this invention to provide an improved method and apparatus for charging ball point pen cartridges with a viscous writing fluid whereby substantially all of the air within the cartridge is removed and air bubbles are eliminated.

It is still another object of this invention to provide" a method and apparatus whereby a plurality of elongated vessels are charged with a fluid medium concurrently.

It is another object of this invention to provide an improved method and apparatus for charging elongated vessels with a fluid medium whereby the vessel is filled to its maximum capacity. g It is another object of this invention to provide an improved method and apparatus for charging elongated vessels with a fluid medium which requires a minimum ice of equipment and which fills a plurality of such vessels rapidly.

It is still another object of this invention to provide an improved method and apparatus for charging elongated vessels with a viscous fluid medium whereby the medium is completely contained within a storage reservoir until transferred directly to the elongated vessels whereby a minimum amount of writing fluid is lost in the operation or deposited upon the outer surfaces of the vessel being filled.

Further and additional objects of the invention will become manifest from a consideration of this description, the accompanying drawings, and the appended claim.

One particular apparatus for accomplishing the above objects is herein shown and described wherein a scalable cylindrical reservoir is mounted for rotation about its cylindrical axis vertically oriented. The reservoir has a plurality of filling orifices or apertures disposed about the periphery of the cylinder, each of said orifices having a spring-biased supporting plunger aligned therewith and in spaced relationship thereto. A pen cartridge may be secured along its longitudinal axis between each of the orifices and an associated spring-loaded plunger. The pen cartridge preferably includes a flexible or flaccid sac for receiving the fluid and is so positioned that its open end is in sealing engagement with the filling orifice in the cylindrical reservoir.

1 The preferred method of operation of this apparatus basically comprises three steps: centrifuging, evacuating, and recentrifuging. Having assembled the cartridges adjacent to the reservoir, the reservoir and cartridges are rotated whereby a viscous fluid medium contained in the reservoir rises upwardly along the peripheral wall thereof and is forced through the plurality of filling orifices into the associated pen cartridges. The centrifugal force acting upon the fluid medium forces the fluid medium outwardly into the pen cartridges and displaces the air therein, whereby the cartridges become substantially filled. It has been found after the first centrifuging step that small bubbles of air have a tendency to remain in the pen cartridge, supposedly at points within the cartridge where small discontinuities in the cartridge surfaces appear. In accordance with one embodiment of this invention these small bubbles are easily removed by stopping the rotation of the cylindrical reservoir and applying a vacuum to said reservoir, whereby a portion of the fluid medium contained within the pen cartridges is withdrawn therefrom. This withdrawal is permitted by a partial collapsing of the flaccid sac containing the fluid. As the fluid is of high viscosity, the drawing of a portion of the fluid medium from the pen cartridge will also draw the bubbles contained within the cartridge toward the open end thereof. This slight drawing of the bubbles will. cause them to become dislodged from their positions behind discontinuities in the cartridge wall, and thus upon again rotating the reservoir and cartridges the dislodged bubbles will be forced from the pen cartridge by centrifugal force acting upon the fluid medium.

For a more complete understanding of the invention reference should now be made to the accompanying drawings, wherein Fig. 1 is a partial plan View of one embodiment of this invention; p

Fig. 2 is an illustration in elevation of the embodiment of Fig. 1 taken substantially along the line 2'2' and i Fig. 3 is an enlarged sectional view of a portion of the embodiment of Fig. 1 taken substantially along the line 3'3 thereof showing one pen cartridge in the filling position.

Referring now to the drawings, and more particularly to Figs. 1 and 2, apparatus for filling a plurality of pen cartridges 12 is shown. The apparatus consists generally of a cylindrical reservoir 14 having a rigid ring 16 mounted in spacedrelationship thereto and havinga plurality of spring-biased plungers 18 (several of which are shown) mounted in spaced relationship about the periphery of said ring. The reservoir 14 has a plurality of filling nozzles 20 disposed in uniform spaced relationship about the circumference of said reservoir, each of said filling nozzles 20 being aligned with a corresponding spring-loaded plunger 18 in the ring 16 and having a central filling orifice extending therethrough. Each of the plungers 18 are so spaced from each of the corresponding nozzles 20 that a cartridge 12 may be sup ported therebetween whereby the open end of the cartridge engages an appropriate filling nozzle 28. The reservoir 14 is rotatably mounted upon a shaft 22 and adapted to be driven by any appropriate motive means as by belt drive 24. As shown more clearly in Fig. 2, the reservoir 14 has a flat circular base 26 and a cylindrical peripheral wall 28 extending upwardly therefrom. The base 26 ha a central collar 38 secured thereto by any appropriate means such as by weld fillets 32, and this collar is in fixed engagement with the rotatable shaft 22. The top of the reservoir 14 is partially enclosed by a cover plate 34 which is secured to the upper edge of the cylindrical wall 28 by any appropriate means such as welding and which has a central circular aperture therein which is adapted to threadably receive a circular cap 36.

The manner in which cap 36 engages cover plate 34 is most clearly shown in Fig. 3. Therein it can be seen that the cap 36 engages the cover plate 34 by cooperating threaded portions 38. A flange 40 extends outwardly from the cap 36 along its upper edge to overlie a corresponding flange 42 extending inwardly along the lower edge of the cover plate 34. Disposed between the

flanges

40 and 42 is an annular resilient gasket 44. This closure 36 is adapted to seal the reservoir whereby it may be partially evacuated as described. A pair of wrenchreceiving holes 46 extend partially through the cap 36, whereby a wrench may be adapted to engage the holes 46 to facilitate rotation of the cap 36 to rigidly secure the cap against the top plate 34, thus compressing the gasket 44 and producing a vacuum seal. A connector 48 threadably engages the central portion of the cap 36 and has a stub 50 extending upwardly therefrom to which a flexible vacuum hose 52 may be attached. The hose 52 extends from the reservoir 14 to an evacuating means such as a pump 54. It should be clear that any appro priate evacuating means may here be provided. The ring 16 as shown most clearly in Fig. 2 is supported in spaced relationship to the reservoir 14 by four brackets having base portions 56 welded to the reservoir and extending radially therefrom. A vertical support 58 extends upwardly from each of the base portions 56 to which the ring 16 is secured by any appropriate means such as the weld fillets 60.

Referring now to Fig. 3, the supporting structure for the cartridges 12 will be more fully described. Each of a plurailty of apertures 62 in the cylindrical wall 28 of the reservoir 14 is threaded to receive a nozzle 20. The nozzle 20 has a central filling tube 66 which extends outwardly from the wall of the cylinder 28 and rigidly engages the tip portion 68 of the cartridge 12. Each filling tube 66 has a filling orifice or aperture extending therethrough. A cup 70 is integrally formed with the tube 66 and adapted to receive an annular gasket 72 which may be cemented in place. The tip portion 68 of the cartridge is adapted to enclose the end portion of the filling tube 66 and resiliently engage the annular gasket 72 surrounding said tube.

The tip portion 68 of the cartridge has a flaccid sac 74 secured to the rearward end thereof. The sac 74 is secured to the tip 68 and supported in a generally longitudinally extended position by a protective metal sheath 76. The sheath 76 is crimped as at 78 to engage the tip 68 with the end of the flaccid sac 74 disposed therebetween. The closed end 64 of sheath 76 is provided with a vent 86 which will allow the passage of air from the space between the sac and the sheath during the filling step and will allow re-entry of air during the partial evacuation step to be described and during the writing operation when the instrument is in use. The plunger 18 comprises a plunger shaft 82 which is slidably mounted within a bushing 84. Bushing 84 has an outside diameter substantially the same as an aperture 86 in the ring 16 and i adapted to frictionally engage the ring. The bushing 84 has a collar 88 at one end thereof so that the bushing may be forced outwardly through the aperture 86 until the flange 88 engages the inner surface of the ring 16. Disposed between the flange 88 and a sheath-engaging cup 90 on the plunger shaft 82 is a coil spring 92 which will normally urge the plunger shaft 82 inwardly whereby the sheath-engaging cup 90 will resiliently engage the end of the sheath 76 and urge the cartridge 12 radially inward to produce an air-tight seal between the tip portion 68 of the cartridge and the annular gasket 72. The plunger shaft 82 has a reduced threaded portion 94 at the outer end thereof which threadably engages a knob 96 which has a correspondingly threaded bore therein. The knob 96 serves to limit the inward travel of plunger shaft 82 under the influence of coil spring 92 when the cartridge 12 has been re moved from the apparatus. The knob 96 further serves as a convenient means for gripping the shaft 82 during the positioning of a cartridge in the apparatus. It will i be apparent that spring 92 ha sufiicient strength to overcome the centrifugal forces operating during the centrifuging steps.

The manner in which this apparatus operates is as follows. An operator places a plurality of cartridges in the apparatus, each of the cartridges being positioned with its open forward end in engagement with a nozzle 28 and encompassing the associated filling tube 66. The closed end of each cartridge is engaged by the cup and resiliently supported in this position by the coil spring 92. It will be understood that at this stage the ballsecuring portion of the cartridge has not been attached to the forward end thereof. The reservoir 14 is partially filled with a viscous writing fluid 98 whereby the surface of the writing fluid is substantially below the plane of the filling nozzles 20. At this time the cap 36 is placed in position to close the reservoir 14, and the evacuating tube 52 is removed from the stub 50. The reservoir is then rapidly rotated whereby the fluid within the reservoir 14 will rise by centrifugal action along the cylindrical wall 28, somewhat as shown by the dotted line 100 in Fig. 2. As described above, this will cause the fluid 98 to enter the cartridges 12 and the sacs 74, the air being expelled through the tubes 66. When this centrifuging operation has been carried on for a predetermined time, rotation is stopped, the tube 52 is placed over the stub 50, and the evacuating pump 54 is actuated to substantially reduce the pressure within the reservoir 14. This results in the withdrawal of a small amount of the writing fluid from each of the cartridges 12, as above described, with the attendant partial collapse of each sac 74. As may be seen from the sectional view of the cartridge of Fig. 3, a bubble has a tendency to remain within the cartridge at the juncture 102 of the sac with the tip portion 68 of the cartridge during the first centrifuging step. In evacuating the reservoir 14 such a bubble will be dislodged and move with the fluid being withdrawn from the cartridge into the fluid path 104 within the tip portion 68. It may not be necessary completely to remove the bubble from this fluid path as this will be accomplished by a subsequent centrifuging operation. It will be understood that the cup 90 is not hermetically sealed to the rearward end of the sheath 76 so that the vent 80 is effective to permit the ready partial collapse of the sac during the evacuation step.

After the application of the vacuum the flexible tube 52 is removed from the stub 50 and the reservoir 14 is again rapidly rotated to force the fluid medium 98 to rise along the cylindrical wall 28 and again fill the cartridges to their maximum capacity. This second filling operation will cause any air bubbles or air which may be in the fluid path 104 to move inwardly toward the center of rotation and be expelled from the cartridge. The machine is then stopped, the completely filled cartridges removed from their respective positions, and the machine reloaded for subsequent operation. As will be understood the tip portion 68 of each cartridge is externally threaded to engage a pen barrel and has internal threads along the forward end of the fluid path 104 to engage a tip member (not shown) having a ball-type writing point. The insertion of the tip member within the forward end of the portion 68 will displace a predetermined amount of writing medium which is now contained Within the fluid path 104 and will force this predetermined amount outwardly into the tip member whereby the ball is completely surrounded with fluid, thus placing the cartridge in writing condition.

One particular embodiment of this invention which has been found especially adapted for use in filling the cartridges of ball point pens comprises a fluid reservoir 14 which is approximately fourteen inches in diameter and has a ring 16 supported in spaced relationship thereto having a diameter of approximately twenty-three inches. The reservoir, it has been found, may be rotated at approximately 500 R. P. M. when using a typical ball point writing fluid having a viscosity in the range between eight and ten thousand centipoises. This speed will be suflicient to cause the fluid to rise along the cylinder wall and will produce sufiicient force to displace the air within the flaccid sacs. The particular embodiment herein described has fifty-eight cartridge-filling positions, but it should be clear that any number of cartridges may be simultaneously filled, depending only upon the diameter of the reservoir and the spacing of the cartridges. 'In using this particular apparatus in the manner above described it has been found that an initial centrifuge period of approximately two minutes is suflicient to substantially fill all of the cartridges and that an evacuating period of approximately one-half minute at a vacuum of twentynine inches of mercury is suflrcient to dislodge substantially all of the bubbles contained within the cartridge. A second two-minute centrifuge period is then provided to refill the cartridge to its maximum capacity. While this sequence of operations has been found especially well adapted for the particular apparatus herein described, the time interval of the various operations may be found by experimentation under varying conditions.

This invention has particular application to filling cartridges for ball point writing instruments having flaccid sac fluid reservoirs of the character disclosed in United States Patent No. 2,444,003 to Chesler.

Without further elaboration, the foregoing will so fully explain the character of my invention that others may, by applying current knowledge, readily adapt the same for use under varying conditions of service, while retaining certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured to me by the following claim.

I claim:

A method of charging a collapsible elongated vessel having one open end with a viscous fluid medium comprising providing a supply of such fluid medium at the open end of such vessel, rotating the vessel about an axis transverse to the axis of said vessel and displaced a predetermined distance from the open end thereof whereby the fluid will substantially fill the vessel, stopping the rotation of said vessel, partially evacuating the vessel to partially collapse said vessel to free any entrapped air therein and subsequently rotating the vessel about said transverse axis to refill said vessel with such fluid substantially free of entrapped air.

References Cited in the file of this patent UNITED STATES PATENTS 701,466 Ciepek June 3, 1902 1,397,061 Smith Nov. 15, 1921 1,679,386 Tenney Aug. 7, 1928 1,761,228 Peck June 3, 1930 2,359,082 Boylan Sept. 26, 1944