EP0436264A1 - Dropper construction - Google Patents
Dropper construction Download PDFInfo
- Publication number
- EP0436264A1 EP0436264A1 EP90300015A EP90300015A EP0436264A1 EP 0436264 A1 EP0436264 A1 EP 0436264A1 EP 90300015 A EP90300015 A EP 90300015A EP 90300015 A EP90300015 A EP 90300015A EP 0436264 A1 EP0436264 A1 EP 0436264A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- dropper
- tip
- cavity
- passage
- cap
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D47/00—Closures with filling and discharging, or with discharging, devices
- B65D47/04—Closures with discharging devices other than pumps
- B65D47/06—Closures with discharging devices other than pumps with pouring spouts or tubes; with discharge nozzles or passages
- B65D47/18—Closures with discharging devices other than pumps with pouring spouts or tubes; with discharge nozzles or passages for discharging drops; Droppers
Definitions
- the capillary passage 20 has a uniform diameter along its length which is dimensioned to permit flow therethrough by capillary effect only.
- the neck 22 is formed of relatively thick material in comparison to the diameter of the capillary passage 20, to resist deformation of the diameter of the capillary passage 20 as ejecting pressure is applied to the reservoir 16, so as to provide a uniform flow of liquid from the reservoir 16 through the capillary passage 20 irrespective of the pressure applied by hand to the reservoir 16 within a reasonable range.
- the flow is controlled primarily by surface forces in the passage 20.
- Figures 4 and 5 show some variation to the structure shown in Figures 2 and 3.
- the capillary passage 20 may be made shorter than the length of the neck 22, to provide a cavity 47 in the neck. This modification does not affect the effectiveness of the device, but enables molding of the dropper 10 to be more readily effected.
- the dropper 100 is molded in a two-part mold, which leaves a visible mold part line 114.
- this inconsistency problem is overcome.
- the prior art dropper 100 has no mechanism for remolding the tip.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Closures For Containers (AREA)
Abstract
A dropper (10) for dispensing liquids in droplets of consistent size has a circular tip orifice (26) of predetermined diameter supplied with liquid via a capillary passage (20) of non-deformable diameter. Preferably, the dropper has a closure cap (14) of harder material than the tip (24) and is provided with an axially-directed projection (38) of complementary shape to a tip cavity (30) whereby upon closing the dropper the tip is remolded.
Description
- The present invention relates to a dropper construction for the discharge of drops from a reservoir of liquid.
- For the oral administration of certain vaccines, such as poliomyelitis vaccine, it is necessary for a reliable and accurate dosage to be provided. In this regard, the World Health Organization now requires polio vaccine to be administered as two drops each of 0.05 ml. Unfortunately, there does not exist a dropper able to function reproducibly and accurately in this manner, although attempts have been made in the prior art. The absence of such a device has lead to the development of the present invention.
- In accordance with the present invention, there is provided a novel dropper structure which is able to provide a reliable and consistent drop of liquid from a reservoir thereof within the body of the dropper. The reservoir is connected via a capillary passage to a tip from which the drops fall and which is capped when not in use.
- In the present invention, it is essential for the capillary passage to have a fixed cross-sectional dimension which does not alter as a result of differences in pressure applied to the resiliently-flexible reservoir, so that the flow of liquid through the capillary passage is controlled by surface forces. In this way, irrespective of the pressure applied by hand to the reservoir to eject the liquid therefrom, within a reasonable range, the same volume of liquid is delivered to the tip.
- The tip is dimensioned to have a diameter which corresponds to the volume of liquid to be ejected as a single drop from dropper. It is known that the weight of a droplet released from an orifice corresponds to the formula:
W = 2π r ST f
where W is the drop weight, r is the radius of the orifice, ST is the surface tension at the point of wetting and f is a connection factor which depends on the orifice radius and the material of construction of the tip. - Although standard textbooks provide information with respect to f, we have found this information to be incorrect. We have found that the connector factor f is determined by the relationship:
f = 0.998 - 1.119X + 0.793X² + 0.1520X³ - 0.265X⁴
where X = arV⁻0.33
a = an empirical factor depending on tube material and solution.
r = orifice radius
V = drop volume - The invention is described further by way of illustration, with reference to the accompanying drawings, in which:
- Figure 1 is a perspective view of a dropper constructed in accordance with one embodiment of the invention;
- Figure 2 is a close-up sectional view of the head of the dropper of Figure 1 illustrating the structure of the head and droplet formation;
- Figure 3 is a close-up sectional view of the head of the dropper assembled with the cap;
- Figure 4 is a close-up sectional view of an alternative form of the head of the dropper of Figure 1;
- Figure 5 is a close-up sectional view of the head of the dropper of Figure 4 assembled with the cap;
- Figure 6 is a perspective view of a typical prior art dropper structure which is improved by the structure of the invention;
- Figure 7 is a part-sectional view of the dropper of Figure 6 assembled with its cap;
- Figure 8 is another part-sectional view of the dropper of Figures 6 during drop formation;
- Figure 9 is a close-up sectional view of a further alternative form of the head of the dropper of Figure 1; and
- Figure 10 is a close-up sectional view of the head of the dropper of Figure 9 assembled with the cap.
- Referring to the drawings, a
dropper 10 comprises adropper body 12 and acap 14. Thebody 12 is molded as one piece in a seamless mold, so as to provide an entirely smooth external surface, particularly in the area of the tip, from any convenient polymeric material, such as low density polyethylene. Thebody 12 includes an elongate generallycylindrical reservoir 16 which is deformable by squeezing to eject drops of liquid, such as polio vaccine, from thereservoir 16. Usually, the reservoir contains a convenient multiple of unit doses. For example, with polio vaccine, thereservoir 16 typically contains 10 or 20 unit doses. - The generally
cylindrical reservoir 16, which is heat-sealed closed by heat seal 18 at one end, communicates with acapillary passage 20 in aneck 22 of thedropper body 12. Thecapillary passage 20 has a uniform diameter along its length which is dimensioned to permit flow therethrough by capillary effect only. Theneck 22 is formed of relatively thick material in comparison to the diameter of thecapillary passage 20, to resist deformation of the diameter of thecapillary passage 20 as ejecting pressure is applied to thereservoir 16, so as to provide a uniform flow of liquid from thereservoir 16 through thecapillary passage 20 irrespective of the pressure applied by hand to thereservoir 16 within a reasonable range. The flow is controlled primarily by surface forces in thepassage 20. - Located at the downstream end of the
neck 22 is atip 24. Thetip 24 has acircular orifice 26 which is of a diameter to ensure that each liquid drop which falls from theorifice 26 always contains the same predetermined volume of liquid. Thetip 24 has an entirelysmooth surface 28 of contact with the liquid and a cylindrical or slightlytapered cavity 30 extending into thetip 24 to thepassage 20. Theorifice 26 thereby is defined by a sharp right angle edge. - The
cap 14 also is molded as a one-piece construction from a polymeric material and is intended to function as a fluid-tight end closure for thebody 12 when thedropper 10 is not in use, so that liquid is not lost from thereservoir 16, nor can contaminants enter the liquid reservoir. - The
cap 14 includes a series ofcircular ridges cap 14 and arranged to grip the outer surface of theneck 22 when thecap 14 is positioned in its closing position. An axially inwardly directedprojection 38 from the end wall of thecap 14 is arranged to project accurately into thecavity 30 of thetip 24 when thecap 14 is in its closed position. - The
projection 38 has a diameter and shape such that it snugly fits into thecavity 30 when thecap 14 is assembled to thebody 12 so that the external surface of theprojection 38 engages the internal surface of thecavity 30. Theprojection 38 includes atapered nose portion 40 which projects into and engages theorifice 42 at the downstream end of thecapillary passage 20 when thecap 14 is fully assembled to thebody 12, thereby preventing liquid flow out of thepassage 20. - One of the ridges, namely
ridge 32, is arranged to engage thetip portion 24 of thedropper 10 so that the walls of thecylindrical cavity 30 are gripped between thatridge 32 and theprojection 38. Thecap 14 is generally formed of harder polymeric material than thetip 24, so that insertion of theprojection 38 into thecavity 30 of thetip 24 and gripping of the wall of thecavity 30 between theprojection 38 and theridge 32, in effect, remolds thetip 24 each time thecap 14 is put on thedropper 10. This arrangement ensures that the shape of thetip 24, and, in particular, the size and shape of theorifice 26, is maintained and hence the drop of liquid falling from thetip 24 is consistently of the same volume, irrespective of the rate at which such droplets are formed and fall from thetip 24. - The
cap 14 has an outer surface having longitudinally-extending ridges which permit thecap 14 to be gripped readily for removal from thebody 12 and reassembly with thebody 12. Thecap 14, at its open end, has a radially-extendingrim 46, which facilitates machine assembly of thecap 14 to thebody portion 12 prior to filling thereservoir 16 with liquid and formation of the heat seal 18. - Figures 4 and 5 show some variation to the structure shown in Figures 2 and 3. As seen therein, the
capillary passage 20 may be made shorter than the length of theneck 22, to provide acavity 47 in the neck. This modification does not affect the effectiveness of the device, but enables molding of thedropper 10 to be more readily effected. - In addition, an
annular shoulder 48 is cut into the periphery of thesurface 28, leaving a ring with sharp right angle edges, which produces improved drop uniformity with certain materials. - At the present time, oral polio vaccine is dispensed from a tube of uniform diameter as three drops per dose. One attempt to provide a more consistent volume of droplet is illustrated in Figures 4 to 6. However, the
dropper 100 illustrated therein is not effective in this regard, for a number of reasons. As can be seen, as initially provided, thebody 102 has a membrane closure to thereservoir 106. Thecap 108 has aprong 110 which is intended to pierce the membrane to permit liquid to be dispensed from thereservoir 106. Unfortunately, this piercing action does not produce a consistent opening and leaves ragged edge remnants of the membrane in theorifice 112. This problem is avoided in the structure of this invention. - In addition, the
dropper 100 is molded in a two-part mold, which leaves a visiblemold part line 114. The presence of thismold part line 114, which is of inconsistent dimension, adjacent to and extending into the droplet-formingorifice 116 leads to inconsistency of droplet size. By molding thedropper 10 with smooth walls, this inconsistency problem is overcome. In addition, theprior art dropper 100 has no mechanism for remolding the tip. - Figures 9 and 10 show further variation to the structure shown in Figures 2 and 3. As seen therein, the
capillary passage 20 is made very short, thereby lengthening thecavity 47 in the neck. By providing this structure, molding of thedropper 10 is even more readily effected without adversely affecting the effectiveness of the device. - As in the arrangement of Figures 9 and 10, an
annular shoulder 48 is cut into the periphery of thesurface 28, leaving a ring with sharp right angle edges, which produces improved drop uniformity with certain materials. In addition theorifice 26 is provided in conical form, with the cap projection being formed with a complimentarily-shaped surface, again for ease of molding without adversely affecting the effectiveness of the device. - The invention is illustrated further by the following example:
-
Droppers 10 were molded from low density polyethylene. Thebody 12 was formed from the low density polyethylene sold by USI Chemicals under the trademark "PETROTHENE R" grade NA226 while thecap 14 was molded from PETROTHENE grade NA201, a harder polyethylene. - The
dropper 10 was dimensioned with a body length of 66.5 mm, a reservoir diameter of 10.7 mm, a capillary passage diameter of 1.5 mm, a tip diameter of 5.3 mm, an orifice diameter of 3 mm and an overall length of capillary passage and cavity of 13.5 mm. These dimensions and materials are intended to provide droplets of consistent size 0.05 ml ± 0.005 ml. - Two runs were made and two droppers chosen at random from a batch filled with polio virus vaccine having a density of 1.2057 g/ml. Drops were ejected from each dropper and the weight of liquid in each drop determined. The results are reproduced in the following Table:
TABLE TUBE # 1 TUBE # 2 WT (gms) WT (gms) .056 .052 .054 .049 .059 .059 .062 .060 .061 .055 .062 .054 .058 .054 .060 .053 .063 .056 .056 .054 .060 .063 .059 .057 .060 .059 .065 .056 .060 .060 .055 .060 .062 .059 .058 .059 .064 .060 .059 .059 .061 .056 .060 .054 .061 .058 .052 .055 .061 .058 .061 .055 .060 .055 .058 .058 .057 .058 .058 .055 .051 .064 .052 .056 .058 .064 .059 .056 .060 .065 .063 .060 .056 .061 .058 .063 .067 Average: .057 .059 Coefficient of Variation: 6.2% .054 .060 .052 .068 Average: .059 Coefficient of Variation: 6.4% - For the volume of liquid in each drop, the individual determined amount is divided by the density (1.2057). For Tube # 1, the total number of droplets was 44, representing 22 two-drop doses, the average weight of the droplets was 0.059 g and the average volume of the droplets was 0.049 ml. The coefficient of variation (ie the ratio between the standard deviation of the measurements and the average measurement) was quite small, 6.4%.
- For Tube # 2, the total number of droplets was 38, representing 19 two-drop doses, the average weight of the droplets was 0.057 g and the average volume of the droplets was 0.048 ml. The coefficient of variation for this group was only 6.2%. These results show the consistency of droplet size obtained using the dropper arrangement of the present invention.
- In summary of this disclosure, the present invention provides a novel dropper arrangement which ensures a consistent droplet size to be maintained. Modifications are possible within the scope of this invention.
Claims (10)
1. A dropper for dispensing liquids in droplets comprising a reservoir (16) for said liquid within the body (12) of the dropper (10); a neck (22) extending from the reservoir to a tip (24); and a passage (20) formed through said neck (22) communicating with said reservoir (16) and said tip (24), characterized in that said passage (20) is a capillary passage, said neck (22) has a sufficient thickness in the region of said passage (20) to avoid deformation under the influence of the pressure of liquid flowing through said passage (20), and said tip (24) has a circular orifice (26) of diameter corresponding to the volume of liquid required in each droplet.
2. A dropper as claimed in Claim 1, wherein the tip (24) includes a cavity (30) extending from the downstream end of the capillary passage (20) to the orifice (26).
3. A dropper as claimed in Claim 2, wherein said cavity (30) has a uniform diameter along its length.
4. A dropper as claimed in Claim 2, wherein said cavity (30) is slightly outwardly tapered towards its downstream end.
5. A dropper as claimed in any one of Claims 2 to 4, wherein the tip (24) has a smooth flat end wall (28) and the cavity (30) defines with the end wall (28) a sharp perpendicular edge to the orifice (26).
6. A dropper as claimed in any one of Claims 2 to 5, wherein a further cavity (47) is formed in said neck (22) at the downstream end of said reservoir (16) and said capillary passage extends from said further cavity (47) to said cavity (30).
7. A dropper as claimed in any one of Claims 2 to 6 including a closure cap (14) for fitting over the neck (22) and tip (24) to provide a fluid tight closure when the dropper (10) is in use, said closure cap (14) being formed of harder material than the tip (24) and having an axially-directed projection (38) of a complementary shape to that of the cavity (30) of the tip (24) to be received in snug fit into the cavity (30) whereby the tip (24) is remolded upon closing the dropper.
8. A dropper as claimed in Claim 7, wherein the axially-directed projection (38) includes a tapered nose portion (40) which extends into the downstream end of the capillary passage (20) and engages a shoulder (42) at the downstream end of the passage (20) to prevent liquid flow therethrough when the cap (14) provides the fluid tight closure.
9. A dropper as claimed in Claim 7 or 8, wherein the closure cap (14) has a radially inwardly extending annular ridge (32) arranged to engage the outer wall of the tip (24) to grip the cavity (30) between the ridge (32) and the axially-directed projection (38) when the cap (14) provides the fluid tight closure.
10. A dropper as claimed in any one of the preceding claims, including a clsoure cap (14) having a plurality of radially inwardly extending annular ridges (32, 34, 36) arranged to engage the outer surface of the neck (22) in interference fit to provide a fluid tight closure when the dropper is not in use.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP90300015A EP0436264A1 (en) | 1990-01-02 | 1990-01-02 | Dropper construction |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP90300015A EP0436264A1 (en) | 1990-01-02 | 1990-01-02 | Dropper construction |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0436264A1 true EP0436264A1 (en) | 1991-07-10 |
Family
ID=8205246
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90300015A Withdrawn EP0436264A1 (en) | 1990-01-02 | 1990-01-02 | Dropper construction |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP0436264A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1195103A1 (en) * | 2000-10-05 | 2002-04-10 | L'oreal | Applicator and container with said applicator |
FR2855818A1 (en) * | 2003-06-06 | 2004-12-10 | Yves Ducroquet | Liquid product e.g. perfume, applicator device, has cover with six capillary channels whose ends open in liquid product sampling tube, where tube is realized to retain quantity of product by capillary phenomenon |
WO2007090561A1 (en) * | 2006-02-06 | 2007-08-16 | Heraeus Kulzer Gmbh | Dental container comprising a dropper insert which can be closed in an evaporation tight manner |
EP2923598A1 (en) * | 2014-03-26 | 2015-09-30 | GEKA GmbH | Applicator with internal, passive reservoir surrounded by wings |
IT201600126875A1 (en) * | 2016-12-15 | 2018-06-15 | Oftalab S R L | Dispenser of ophthalmic solutions applicable to single-dose containers |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2798644A (en) * | 1955-11-22 | 1957-07-09 | Bradley Container Corp | Squeeze container with drop forming spout |
WO1984000707A1 (en) * | 1982-08-12 | 1984-03-01 | American Hospital Supply Corp | Dispensing bottle and method |
EP0255492A2 (en) * | 1986-07-31 | 1988-02-03 | Capsulit S.P.A. | A closure for a bottle or the like equipped with a dropper |
-
1990
- 1990-01-02 EP EP90300015A patent/EP0436264A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2798644A (en) * | 1955-11-22 | 1957-07-09 | Bradley Container Corp | Squeeze container with drop forming spout |
WO1984000707A1 (en) * | 1982-08-12 | 1984-03-01 | American Hospital Supply Corp | Dispensing bottle and method |
EP0255492A2 (en) * | 1986-07-31 | 1988-02-03 | Capsulit S.P.A. | A closure for a bottle or the like equipped with a dropper |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1195103A1 (en) * | 2000-10-05 | 2002-04-10 | L'oreal | Applicator and container with said applicator |
FR2814923A1 (en) * | 2000-10-05 | 2002-04-12 | Oreal | APPLICATOR AND CONTAINER PROVIDED WITH SUCH AN APPLICATOR |
US6666607B2 (en) | 2000-10-05 | 2003-12-23 | L'oreal S.A. | Applicator and method for applying a product |
FR2855818A1 (en) * | 2003-06-06 | 2004-12-10 | Yves Ducroquet | Liquid product e.g. perfume, applicator device, has cover with six capillary channels whose ends open in liquid product sampling tube, where tube is realized to retain quantity of product by capillary phenomenon |
WO2004110900A2 (en) * | 2003-06-06 | 2004-12-23 | Rexam Dispensing Systems | Application device for liquid product |
WO2004110900A3 (en) * | 2003-06-06 | 2005-02-24 | Yves Ducroquet | Application device for liquid product |
US7338228B2 (en) | 2003-06-06 | 2008-03-04 | Rexam Dispensing System S.A.S | Application device for liquid product |
WO2007090561A1 (en) * | 2006-02-06 | 2007-08-16 | Heraeus Kulzer Gmbh | Dental container comprising a dropper insert which can be closed in an evaporation tight manner |
EP2923598A1 (en) * | 2014-03-26 | 2015-09-30 | GEKA GmbH | Applicator with internal, passive reservoir surrounded by wings |
US9788636B2 (en) | 2014-03-26 | 2017-10-17 | Geka Gmbh | Applicator with an internal passive reservoir delimited by wings |
IT201600126875A1 (en) * | 2016-12-15 | 2018-06-15 | Oftalab S R L | Dispenser of ophthalmic solutions applicable to single-dose containers |
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