Method of sealing ampoules
United States Patent 2464765

This invention relates to the art of sealing ampules such as are used for containing various kinds of medicinal and other therapeutic preparations, both in powder and in liquid form. Such ampules a re usually made of glass and they may be of various sizes. One representative size ,may be in...

Palmer, Frank D.
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53/477, 65/108
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This invention relates to the art of sealing ampules such as are used for containing various kinds of medicinal and other therapeutic preparations, both in powder and in liquid form.

Such ampules a re usually made of glass and they may be of various sizes. One representative size ,may be in the neighborhood of six inches long and about three-quarters inches in diameter. Such ampules are commonly furnished by the manufacturer of ampules to the manufacturer of thera:peutics, etc., with one end open, the other end having been closed in the processn of producing he ampule t a It has long been the practice by therapeutic tmanufacturers to fill ampules, of the above men- iad tioned type, with the desired quantity of powder or liquid and to effect closing and sealing of the open end of the ampule bymanual labor. In the manual operation, a portion of the.ampule; above the level of the material therein, is heated until such portiont is softened whereupon the open end portion of the ampule is pulled away from the lower portion in such a way that the diameter of the heated portion contracts and effects the closing of the ampule. The contracting and closing is usually brought about by rotating or twisting one part of the ampule while the other part is held against rotation and pulled longitudinally from the rotated part. To facilitate, this- operation rand to reduce the time required to heat the ampule to .30 the required fusing temperature of the glass, the most commonly used ampules have been initially provided with an elongated, reduced-diameter mouth portion. The reduced diameter mouth portion has usually been formed: by heating the .m5 ampule and pulling one part away from the other qnuch as inthe process of sealing filled ampules as above described.

The sealing of ampules in the conventional *manner above referred to and the production of 4.o reduced mouth portions in a corresponding man:ner, frequently, if not always, results in the formation on the ampule of an extra.thin walled por,tion which is much more subject to breakage than the other, normal thickness portions thereof. 5b Within recent years, !certain machines have been .developed for filling and closing ampules but they :effect the closing -and sealing substantially by rmechanically carrying out:the-same steps as were ,effected in the manual closing ,and sealing, of ampules as already'referred to; hence, the objectional thinned wall portions are often, if not always, present in the mechanically sealed ampules as well as in manuallysealed ampules.

The main object of thepresent invention is to provide an improved method of closing and sealing an ampule so as to avoid any material reduction of the thickness of any part of the closed and sealed ampule; to. provide such a method which may be practicably effected by mechanical means which will operate at ahigh rate of speed; to provide an improved ampule closing and sealing method which wil facilitate the closing and sealing operations byeliminating the production of vapors in the ampule by reason of heat transmitted through the wallsof the ampule to any liquid preparation delivered into the ampule; and in general it is the object of the invention to provide an improved ampule closing, and sealing method.

Other objects and, advantages of the invention gwill be understoodbyreferenc e to thefollowing specification and accompanying drawing wherein there is more or less diagrammatically illustrated a selected embodiment of the invention and certain modifications thereof. In the drawings: Figs. 1 to 6, inclusive, are diagrammatc illustrations of the successivfe stes of improved method; Figs. 7 and 8 are fragmentary plan sections on the lines 7-7 and 8-8 of Figs. 2 and 5, respectively; Fig. 9 .illustrates .the beginning of a modified tmethod; Fig. 10 is a fragmentary illustration corresponding to a portion of Fig. 5 showing a modified arrangement; and Fig. 11 is a further modification of the closing step represented in Fig 5.

A typical glass ampule in the form in which it is received by the therapeutic manufacturer from the ampule manuifacturer. is shown in Fig. 1. It consists of an elongated cylindrical side wall 12 and a bottom wall 13.

The ampule is usually provided intermediate its ends with a slightly reduced circumferentially extending portion 14 which serves to facilitate opening of the ampule after it is closed. Opening iS usually effected by drawing a file across the ampule in, the groove formed by the reduced portion 14 so as to scratch the glass whereupon the ampule may be readily broken transversely in the zone of the groove 14.

The ampule is preferably rotated during the heating and other steps hereinafter described, there being provided any suitable means for effecting such rotation while holding the ampule temporarily in a fixed position or station and during the movement of the ampule to successive stations.

According to the presently preferred embodiment of the improved method, a straight walled ampule is initially heated in a circumferential zone indicated at 15 by means of flames from suitable gas burners 16. The initial heating of the zone 15 of the ample as shown in Fig. 1 is carried on to such an extent that the glass in the circumferentially extending heated zone is softened. The ample may be advanced by means of a conveyor or other suitable means from the initial heating station to a second station or position wherein a pair of forming fingers or swaging bars 17, 17 approach the softened zone of the ampule and press it inwardly to form an inwardly offset bead or slightly reduced neck portion 18.

The fingers 17, 17 preferably have the ends thereof, which engage the ampule wall, smoothly rounded as indicated at 18. They may be provided with arcuate portions 19, as best shown in Figs. 2 and 7, of a radius corresponding to the radius of the outside of the initially formed neck portion 18. The swaging operation of the fingers 17, 17 is executed while the ampule continues to be subjected to heating flame directed into the zone of the ampule in which the neck 18 is formed.

Suitable gas burners 20 are provided for delivering the desired heating flame against the ampule, preferably immediately below the swaging fingers 17, 17 which are also incidentally heated so as 4 to avoid any material chilling effect on the engaged portion of the ampule.

In a succeeding step in the method, the neck 18 may be further reduced by means of swaging members 21, 21 which are, in general, similar 4 to the fingers 17, 17 except that the opening provided between the arcuate portions thereof is smaller to such an extent that a greatly reduced neck 22 will be formed in the ampule. The heating of the ampule in the last mentioned neck reducing station may be effected by means of gas burners 23, 23 which also preferably direct suitable flames into the neck zone immediately below the swaging members 21, 21.

It will be apparent that instead of forming 5 the neck 22 in only two steps as illustrated, it may be effected in a larger number of steps each of which increases the constriction only a small amount until it has been reduced to the desired size substantially as represented in Fig. 3. 6g In some instances, the ampule may be filled immediately after completion of the formation of the neck 22 and the filling may possibly be executed while the ampule remains in the position in which the final neck forming operation is 65 performed. However, it appears preferable that the filling be executed in a different station to which the ampule' may be automatically advanced after the neck 22 is completed. Preferably, a sufficient time interval is caused to elapse 70 between the final neck forming step and the filling of the ampule to permit the ampule to cool so as to avoid any tendency to vaporize any liquid or other material introduced into the ampule.

The cooling may be artificially hastened, or it 75 may be controlled so as to insure annealing of the glass so as to prepare it for additional heating and flexing operations which will presently be described. If desired, the ampule, after formation of the neck 22, may be passed through a suitable oven for annealing purposes.

A filling station is represented in Fig. 4 and the filling is preferably accomplished by inserting an elongated small diameter spout or needle 24 through the neck 22 and to the bottom of the ampule as illustrated. The required quantity of powder or liquid is delivered through the needle to the ampule after which the needle is withdrawn. The filled ampule is then preferably 13 advanced to still another station where the closing and sealing operation may be effected or at least initiated.

A closing and sealing station is represented in Fig. 5 wherein a pair of sealing fingers or . shears 25, 25 are illustrated as having sheared off the upper end portion of the ampule, the separation having been effected in the zone of the smallest diameter of the neck 22. The neck will have been further heated, to fusing temg perature, by flames delivered by gas burners indicated at 26, 26.

The shear members 25, 25 cooperate with each other to completely close the neck 22, the innermost surface portions of the neck 22 being brought 3) into engagement with each other and caused to fuse together to form a sealed end 27 on the ampule. The cut off end portion 28 may be caught in a suitable tray or chute associated with the sealing station represented in Fig. 5 and disposed j5 of in any desired manner. Rotation of the amPule is preferably continued during the cut off and sealing operation and the end wall 27 of the ampule will, of course, be acted upon by the engaging lower surface of the lowermost shear [0 finger 25. As shown in Fig. 5, the shearing end of the lowermost fingers is preferably beveled as at 29. Such beveled surface and the adjacent undersurface of the fingers will tend to flatten down sealed end wall 27.

S The sealing operation represented in Fig. 5 may be carried on immediately after the filling operation represented in Fig. 4, and if preferred, the neck 22 may first be subjected to a further constriction operation such as represented in 0 Fig. 3 to thereby reduce the work required of the shearing fingers 25, 25. The shearing fingers may be formed with sharpened notched ends as shown at 30, 30 in Fig. 8, the notches serving to embrace the reduced neck 22 of the ampule 5 and to insure uniform inward constriction of the neck as an incident to a closing movement of the shear members and the rotation of the ampule.

After completion of the shearing operation represented in Fig. 5 the newly formed end closure of the ampule may be subjected to a finishing step in which a suitably formed pressure block 31 is brought to bear against the end of the ampule while the latter is maintained in rotation. This block may be made of wood such as ash and it may be maintained water wet to prevent burning thereof. It will be apparent that rotation of the ampule against the pressure block 31 will result in a uniformly flattened or other shaped end wall as may be desired.

In some instances it may be preferred to avoid any end shaping effect of the shears 25, 25 as illustrated in Fig. 5. In such an instance the arrangement shown in Fig. 10 may be employed wherein the shear fingers are represented at 32 and 33.

The lower shear fingers 32 in that case has its sharpened end so beveled or hollow-ground,, as indicated at 34 that its arched or inclined surface will substantially conform to the convex shape of the end of the ampule which would normally result from the closing of theneck 22 by-;a further step such as represented in Fig. 3. A further method by which the end shaping function of the shears shown in Fig. 5 may be eliminated is to employ cooperating shear fingers acting in the I same plane and having cooperating ends which are moved into end to end engagement with each other. Such an arrangement is typified in the modification illustrated in Fig. 11.

In the described method of closing and sealing the ampule, the liquid or other material delivered into the ampule in the step represented in Fig. 4 is not subjected to heating during the preceding steps represented in Figs. 1, 2, and 3. For that reason and because of the cooling of the ampule before filling, there will be but little or no vapor formed in the ampule when it is filled in the step or station represented in Fig. 4.

In some circumstances, it is preferred to fill the ampule before the heating and closing steps are started. In such a case the ampule may be initially filled as represented in Fig. 9 and the initial heating step effected by the burners 16 while the ampule is rotated with its content therein. The neck forming steps represented in Figs. 2 and 3 may be carried on in successive operations. Before the final sealing step represented in Fig. 5 is begun, it may be advantageous to provide for the passage of a sufficient time interval to permit cooling of the ampule and its content and the escape and/or condensation of any vapors which may have been formed within the ampule as an incident to the heating during the various steps through which the ampule passes as already described. Such time interval may be provided in an automatic machine by suitably spacing the positions of the last neck forming operations and the severing and sealing operation, or by any other arrangement for delaying the delivery of a filled ampule from the final neck forming station to the neck closing station. The required time interval may be lessened or completely eliminated by forcibly evacuating or dispelling the vapors by the use of vacuum or compressed air means and by naturally or artificially cooling the ampule, for example, by means of a cool air current. It will, of course, be understood that elimination of vapor, before sealing the ampules, is advisable because, unless such elimination is effected, the heating of the ampule in the final closing and severing steps may sometimes raise the temperature of the ampule to such an extent that any trapped vapors would expand to the point of bursting the ampule.

The formation of the restricted neck portion as a preliminary to the final severing and sealing operation permits the final severing and sealing operation to be performed with the application of a minimum amount of heat which will not be sufficient to vaporize any liquid content normally enclosed in ampules of the character described, or in any event, said minimum amount of heat required will be insufficient to vaporize enough of the ampule content to develop pressure enough within the ampule to burst or prevent closing of the ampule.

As shown in Figs. 2 and 3, the constricting fingers 17 and 21 are disposed at a downwardly inclined: angle. These fingers are preferably moved longitudinally inwardly in a downwardly inclined plane such as the plane in which they are represented, so that they tend to bend or fold the side wall portion 35 inwardly and downwardly without any material stretching and thinning effect on any part of the finished or closed ampule.

The inward and downward folding of the portions 35 is, of course, accompanied by some shortening l of the overall length of the ampule. The upper inwardly pressed wall portions represented at 36 may possibly be stretched and thinned somewhat but since the upper portion of the ampule containing the wall portions 36 is removed, there is no disadvantage in that thinning. It is, however, of substantial value that the end closure forming portion 35 of the ampule is maintained at substantially its normal thickness. The severing operation represented in Fig. 5 similarly avoids any stretching and thinning effect since the severing fingers 25, 25 produce only a very small amount of inward movement of the neck portion 22 of the ampule while at the same time producing some further downward folding of the portion 35.

In prior ampule filling and sealing methods, tapered and reduced mouth end ampules have usually been employed. Such ampules have been used because the lesser amount of heat required had the more or less effective tendency of avoiding vapor pressure bursting of the ampules.

Such tapered ampules, although being the only ones heretofore considered practicable because of the limited heating required for the sealing 'j operation are, however, objectionable because of their inherent weakness due to the thinning of the glass wall in the tapered mouth portion.

The herein described method makes it entirely 4practicable to employ the much more desirable straight walled and stronger ampules which, in addition to their advantage of strength, are adaptable to more compact and less expensive packaging. Also, the described improved method ,.i is such that it may easily be practiced by means of high speed, automatic mechanism.

Modifications, in addition to those mentioned herein, may be made in the described method without departing from the invention as set forth in the following claim.

I claim: The method of producing a filled, closed ampule from a conventional straight-walled ampule, which comprises the steps of heating a circumferential part of the ampule above the normal level of the content of the ampule and, when such part is sufficiently heated, forming a reduced neck in the ampule above said content level by applying to said part pressure directed inwardly and toward the bottom of the ampule so as to avoid stretching and incidental reduction of the thickness of the neck portion which will ultimately close the ampule, the entire ampule being thereby warmed and some of the content of the ampule, whether introduced thereinto before or after formation of said neck, subjected to vaporization, permitting the escape from or condensation in the ampule of vapor which may be present therein and then reheating said reduced neck portion to fusing temperature and severing the ampule transversely at said neck so as to close the neck and effect fusion of the meeting surfaces thereof, whereby the closing is effected without transmitting sufficient heat to .75 the ampule content to cause the production of sufficient vapor in the ampule to hinder the clos- Number ing of the ampule as aforesaid. 1,945,769 FRANK D. PALMER. 1,967,603 2,227,757 REFERENCES CITED 2,2527,74 2,258,408 The following references are of record in the 2,265,359 file of this patent: 2,379,342 UNITED STATES PATENTS Number Name Date 10 Number 596,319 Brooke ----------- Dec. 28, 1897 117,427 1,517,780 Goodchild ---------- Dec. 2, 1924 454,068 1,864,023 Ledig -------------- June 21, 1932 654,167 Name Date Brumley ------------Feb. 6, 1934 Zimber ------------_ July 24, 1934 Loepsinger ------__ _ Jan. 7, 1941 Cozzoli --------------Oct. 7, 1941 De Neumann ---_____ Dec. 9, 1941 Cozzoli ----------- June 26, 1945 FOREIGN PATENTS Country Date Australia ----------_ Sept. 2, 1943 Great Britain ------ Sept. 23, 1936 Germany --_------. Dec. 16, 1937 : :