US3442707A - Apparatus and process for cleaning collapsible tubes - Google Patents

Description

May 6, 1969 3,442,707

APPARATUS AND PROCESS FOR CLEANING GOLLAPSIBLE TUBES H.S.DZEDZEJ Sheet Filed July 21, 1965 m 2 ll? IAVIVENTOR. Afenryafi'fize 26/ ATTORNEYS y 6, 1969 H. s. DZEDZEJ 3,442,707

APPARATUS AND EROCESS FOR CLEANING COLLAPSIBLE TUBES Filed July 21, 1965 Sheet 2 of 2 6; 07 J DRAIN k )sowem I Z I v 6/ 1 2 IAIRHEATER INVEN OR. flew/761026 zeg ATTORNEYS United States Patent 3,442,707 APPARATUS AND PROCESS FOR CLEANING COLLAPSIBLE TUBES Henry S. Dzedzej, Wallingford, Pa., assignor to A. H.

Wirz, Inc., Chester, Pa., a corporation of Pennsylvania Filed July 21, 1965, Ser. No. 473,598 Int. Cl. B08!) 9/00 US. Cl. 134-24 3 Claims ABSTRACT OF THE DISCLOSURE A process and device for cleaning the interior of a collapsible tube having a cap attached at one end in which the tube is supported on a mandrel having a shoulder adjoining a shoulder in the tube and having one or preferably a plurality of orifices through the shoulder, the mandrel having a shank which has a close clearance to create a flow of solvent parallel to the size of the tube.

This invention relates to an apparatus and process for cleaning collapsible tubes and more particularly it relates to an apparatus and process for removing metal particles within the interior of such tubes.

In the production of metal collapsible tubes, fine metal particles are often introduced into the interior of the tube during its formation and in subsequent machining operations especially in the area of the tip of the tube where a cap is to be secured. Data has been compiled and standards have been set with respect to the level of metal particles permissible in tubes where the contents of the tube must of necessity be free from foreign matter such as ophthalmic ointments. Acceptable limits for such ointments have been placed at a level not exceeding 50 particles of over 50 microns in size in any ten tubes of ointment with no one tube containing more than 8 such particles.

These limitations on foreign matter are very restricted and thus it is necessary to provide a system for the effective and eflicient cleaning of tubes after they have been formed and before they are filled in order to meet these standards.

Accordingly an object of this invention is to provide a process for the effective and efiicient cleaning of collapsible tubes.

It is a further object of this invention to provide a system for cleaning capped collapsible tubes suitably made of extruded metal to rid them of substantially all foreign particles.

It is a further object of this invention to provide a system for cleaning collapsible tubes that forces a solvent into a thin stream down along the interior surface of the tubes, expels the solvent out the open end of the tube and subsequently drys the interior of the tube to prepare it for the filling operation.

Another object ofthis invention is to provide a nozzle, which supports the tube during the cleaning operation, and forces the cleaning solvent into the interior of the tube, down the sides of the tube and out its open end.

Another object of the-invention is to provide a nozzle as a supporting element that will allow drainage of the solvent from the tube and prevent the reverse flow of solvent up the outside of the tube during the cleaning operation.

Further objects and advantages will be readily apparent from the following description of the drawings:

FIGURE 1 is a schematic view showing diagrammatically an assembly of elements employed in carrying out my method for cleaning collapsible tubes.

FIGURE 2 is a top view showing the tip of the nozzle and the outlet orifices with the surrounding tube wall in section.

FIGURE 3 is a sectional view taken along the lines 33 of FIGURE 2 showing the nozzle with a capped tube in position for cleaning.

FIGURE 4 is a sectional view taken along the lines 4-4 of FIGURE 3 omitting the tube and showing the drainage channels in the side of the nozzle.

FIGURE 5 is an electrical diagram depicting schematically the necessary circuit for operating the various assembly elements shown in FIGURE 1 in the proper sequential order.

Essentially the invention consists of introducing a solvent under pressure through a nozzle into the interior of a capped collapsible tube near its capped end, forcing it down a narrow space provided between the tube and the shank of the nozzle and out the open end of the tube. By restricting the passage a parallel flow of fluid along the inside surfaces of the tube is created, which effectively flushes all metal particles out the bottom end of the tube. After flushing, the solvent is permitted to drain out of the nozzle and subsequently a blast of air is emittedfrom the nozzle and into the tube to rid it of any excess solvent and to dry it in preparation for filling.

Collapsible tubes have conventionally been cleaned with suction devices as disclosed in US. Patent No. 2,637,872. However, the suction needed to rid the tube of all extraneous matter is often so great that it causes the tube to collapse, thus damaging it and rendering it useless. It is therefore an important aspect of this invention that applicant has provided a novel cleaning process without resorting to the use of suction. By forcing the air through the tube according to this invention, no dam age is inflicted upon the tube itself.

Ultrasonic degreasing has also been used as a cleaning technique but in this method the tubes must be immersed or dipped into a solution. Consequently they must be cleaned by this method before decoration has been applied to the tube, as such a cleaning process would destroy any lacquer or decorative coating thereon.

This invention, however, provides a cleaning system which can be applied at the very last stage of the tubemaking process after all the milling, decorating, capping and other steps have been completed subsequent to the extrusion of the tubes. In ultrasonic degreasing, metal particles may be introduced during these subsequent steps of capping and decorating but in applicants process this is prevented because these operations have already been performed on the tube before it is cleaned.

Referring now to FIGURE 1, there is shown schematically a system for carrying out the process of this invention. The tubes supporting mandrel or nozzle cleaning device is generally indicated as 10. A tube 11 having a cap 12 affixed thereto, has a side wall 11' and a shoulder 11 with its bottom end open, is in position for cleaning over the mandrel or nozzle 10. Above the tube is a guard plate 13 which acts as a stop to prevent the tube from being wholly displaced olf the mandrel when the solvent is introduced under pressure. The plate is also provided with sides 14 which help to prevent the spraying of solvent out of the area in case there is a defect in the tube. These sides on the guard help to contain any free solvent vapors. Th guard, of course, will have to be removed before the tube is inserted on the mandrel and then replaced. This movement may be manually controlled or suitably automatically controlled by a switch coordinated with the starting of a cleaning cycle.

In FIGURE 3, the tube and mandrel are shown in greater detail, the mandrel consisting of a shank 20 having a central orifice 21 communicating with a plurality of smaller orifices 22 at the upper end of the mandrel, thus forming the nozzle end. This end is provided with a shoulder 23 in order to position the tube properly with respect to the mandrel and is slotted at 24 to allow the solvent to drain out the bottom end of the tube. At a lower point but before the bottom of the skirt of the tube is reached, the mandrel is relieved at 25. Between this point 25 and the top edge of the mandrel, the clearance between the tube and the shank of the mandrel should be greater than .005 inch but should not exceed .015 inch except at the locations where the slots 24 exist in the side of a mandrel. This allows the flushing solvent to essentially flow parallel to the tubes inner wall providing a scrubbing action which detaches and removes any foreign particles. It was found, however, that if this clearance was carried along the entire length of the tube that the flushing solvent tended to return up the outside of the tube at the botom end. This has been successfully avoided by providing an additional clearance or relief starting at 25 part of the way down the shank of the mandrel. At this point there should be at least a clearance of .030 inch between the mandrel and the lower portion of the skirt of the tube, the mandrel then having preferably the same diameter as the inside of the drainage channels 24.

It is important also that the collapsible tube 11 be capped with a suitable cap 12 so that the flow of solvent will be directed in a reverse direction down the space between the mandrel and the inside of the tube. The presence of the cap additionally acts to prevent the tip of the tube from being damaged against the guard plate, if the tube is pushed up into it by the force of the flow of solvent. Applicant has thus provided a cleaning element that will effectively flush the inside of the tube without harm to its structure or its outside surface.

Referring again to the flow diagram of FIGURE 1, a source of solvent 28, suitably trichloroethylene or Dupont Freon, is withdrawn through line 29 by pump 30 which continuously pumps to a pressure relief valve 31 that returns the solvent to the source when the system is not discharging solvent through the nozzle 10. During discharge, the solvent passes through a filter or series of filters 34, the pressure of the fluid being indicated by gauge 35. The minimum pressure for the solvent should be at least 50 p.s.i. Solenoid valve 36 controls the discharge of the solvent as shown in the electrical diagram in FIGURE 5. When the valve opens, the solvent passes through a horizontal check valve 37 which prevents the entrance of air into the line and/ or prevents a backwash of the solvent. The solvent then passes up and out the nozzle at its upper end. During this discharge, solenoid valve 38 remains closed so that all of the solvent will pass out through the nozzle.

When it is desired to drain the solvent, the valve 36 closes, interrupting the flow of solvent and the valve 38 opens permitting any solvent remaining in the lines to flow by gravity out of line 39 into container 42. This container surrounds the lower end of the mandrel to also catch the solvent that is expelled out of the bottom end of the tube. All of the solvent then empties by gravity flow through line 43 into sump container having a cover 41. Included in the container is a float switch 44 which when actuated by the level of spent solvent in the container, energizes a return pump 45 sending the spent solvent through a reconditioning filter 46 back to the solvent source 28 to be used again.

After the solvent has been flushed through the tube and given suflicient amount of time to drain, air is introduced into the system through line 47 passing through an optional heater 48 to warm the air as an aid to the drying operation. The air then passes through a regulator 49 and a filter 50 to remove any trace of foreign particles. The flow of air to the system is controlled by solenoid valve 51, which when activated sends the air through check valve 52 up and out the nozzle and down the space between the tube and the mandrel to blow out excess solvent and metal particles and to dry the tube.

A suitable exhaust system is provided as generally indicated at 53 in order to remove any excess solvent vapors which may be present in th area.

Referring now to the electrical diagram in FIGURE 5 there is shown a double pole switch which provides the energy to operate the system. 61 is a microswitch, which is closed mechanically when the guard plate 13 is moved to an operative position. This closed circuit then energize timer 62, and at the same time energizes solenoid valve 36 through normally closed switch 63 thus allowing solvent to flow through the nozzle. Additionally, indicator light 64 is energized to indicate that the flushing stage is in operation. After the timer 62 reaches a predetermined point and runs out, usually 1 to 2 seconds after the solvent begins flowing, the timer opens normally closed switch 63, deenergizing solenoid valve 36, thus closing it and interrupting the flow of solvent. Simultaneously the timer 62, having run out, also closes normally open switch 65 so that it will now energize timer 66 and at the same time energize solenoid drain valve 38 through normally closed switch 67. Indicator light 68 indicates that the draining stage in the operation has been reached. After this timer reaches its predetermined point and runs out, usually two seconds after the fiow of solvent has been interrupted, the timer 66 opens normally closed switch 67, deenergizing solenoid valve 38, thus closing it. Simultaneously the timer 66, having run out, also closes normally open switch 70, energizing timer 71 and at the same time energizing solenoid air valve 51 through normally closed switch 72 to start the flow of compressed air at about p.s.i. through the nozzle. Additionally, indicator light 73 indicates that the drying stage in the operation has been reached. Optionally the air heater 74 can be used to heat the air by manually closing switch 75. After this timer 71 runs out it opens normally closed switch 72 deenergizing and closing the air valve 51 thus completing the cleaning cycle.

I have shown only one mandrel or nozzle for ease in explaining the fiow diagram, but it is apparent that the system can equally be applied to a whole bank of nozzles for the cleaning of a plurality of tubes simultaneously. Preferably they could be provided with an automatic system that would place all the tubes on multiple flushing heads or mandrels, place the guard plate over the top of them and subsequently lift them off after the tubes had been cleaned. Instead of placing a series of tubes simultaneously on to multiple flushing heads, a continuous system using one or a number of heads could also be used according to the process of this invention.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure and process shown, and I therefore claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process for cleaning the interior of a collapsible tube having a cap attached at one end, having a shoulder, having a side wall and open at the end opposite to the cap, which comprises supporting the tube on a mandrel having a shoulder at one end adjoining the shoulder in the tube and having orifices at the shoulder, the mandrel having a clearance from the interior of the side wall of the tube at a plurality of circumferentially spaced points of between 0.005 and 0.015 inch, forcing a solvent through the orifices and down the space between the tube and the mandrel to create a flow of solvent parallel to the sides of the tube, allowing the solvent to drain out of the space between the tube and the mandrel, and forcing heated air under pressure through the orifices and down said space to remove excess solvent and to dry the interior of the tube.

2. A device for cleaning a collapsible tube having a.

cap attached at one end, a shoulder, a side wall and an opposite open end, comprising amandrel for supporting said tube having a shoulder at one end, having a cylindrical shank which has a clearance from the interior of the side Wall of the tube to be placed thereon at a plurality of circumferentially spaced points of between 0.005 and 0.015 inch, said shank having a plurality of orifices one of which is central for the supply of a cleaning fluid opening at the shoulder, and said shank being relieved near the open end of the tube but above the open end of the tube to provide a clearance of at least 0.030 inch between the sides of the mandrel and the interior surface of the bottom end of the side wall of said tube.

3. A device according to claim 2, including a plurality References Cited UNITED STATES PATENTS 4/1945 Weir l3424 X 7/1945 Cozzoli 134152 X 10 DONALL H. SYLVESTER, Primary Examiner.

ARTHUR D. KELLOGG, Assistant Examiner.

US. Cl. X.R.

of longitudinally extending channels in the side of the 15 134-30, 37, 50, 152, 199

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