U.S. patent application number 13/224901 was filed with the patent office on 2012-02-09 for method and apparatus for sealing medicinal capsules.
This patent application is currently assigned to BOEHRINGER INGELHEIM PHARMA GMBH & CO. KG. Invention is credited to Dieter HOCHRAINER, Herbert WACHTEL.
Application Number | 20120031802 13/224901 |
Document ID | / |
Family ID | 27214525 |
Filed Date | 2012-02-09 |
United States Patent
Application |
20120031802 |
Kind Code |
A1 |
HOCHRAINER; Dieter ; et
al. |
February 9, 2012 |
METHOD AND APPARATUS FOR SEALING MEDICINAL CAPSULES
Abstract
A method of sealing parts of a plastic capsule by forming a weld
seam in an overlapping region of the parts of the capsule, wherein
the capsule comprises a capsule cap having an open end and a
capsule body having an open end, and capsules formed by such
method. The capsules produced by the process according to the
invention are disposable and preferably contain a single dose of a
pharmaceutical formulation in the form of a powder or liquid
intended to be administered by inhalation and are suitable by their
form and function for use in powder inhalers or liquid nebulizers
for producing aerosols. Aerosols thus produced can be inhaled, for
example, in order to administer a pharmaceutical formulation to the
lungs.
Inventors: |
HOCHRAINER; Dieter;
(Schmallenberg, DE) ; WACHTEL; Herbert; (Ingelheim
am Rhein, DE) |
Assignee: |
BOEHRINGER INGELHEIM PHARMA GMBH
& CO. KG
Ingelheim am Rhein
DE
|
Family ID: |
27214525 |
Appl. No.: |
13/224901 |
Filed: |
September 2, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11102256 |
Apr 8, 2005 |
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13224901 |
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10201443 |
Jul 23, 2002 |
6949154 |
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11102256 |
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60363657 |
Mar 12, 2002 |
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Current U.S.
Class: |
206/524.6 ;
156/272.8; 156/60; 428/34.1; 428/35.7 |
Current CPC
Class: |
B29C 66/961 20130101;
B29C 65/1616 20130101; B29C 65/1638 20130101; B29C 66/9141
20130101; B29C 2035/0822 20130101; B29C 66/73921 20130101; B29C
66/12821 20130101; B29C 2035/0216 20130101; B29C 66/71 20130101;
Y10T 156/10 20150115; B29C 66/1142 20130101; B29C 65/58 20130101;
B29C 66/1284 20130101; B29C 66/939 20130101; Y10S 53/90 20130101;
B29C 66/71 20130101; B29C 65/10 20130101; B29C 66/65 20130101; Y10T
428/13 20150115; B29C 66/71 20130101; A61J 3/072 20130101; B29C
66/836 20130101; B29C 66/1222 20130101; B29C 65/1677 20130101; B29C
65/103 20130101; B29C 66/1122 20130101; B29C 66/1224 20130101; B29C
66/71 20130101; B29C 66/71 20130101; B29C 66/73115 20130101; B29C
65/1654 20130101; B29C 66/73151 20130101; B29K 2995/007 20130101;
B29C 66/7352 20130101; B29C 66/652 20130101; B29K 2995/0073
20130101; B29C 66/9121 20130101; B29L 2031/7174 20130101; Y10T
428/2982 20150115; B29C 66/003 20130101; B29C 66/919 20130101; B29C
66/93451 20130101; B29C 66/71 20130101; B29C 66/71 20130101; B29C
66/9161 20130101; B29C 66/5432 20130101; B29C 66/54 20130101; B29C
66/73321 20130101; B29C 66/12441 20130101; B29C 66/71 20130101;
Y10T 428/1352 20150115; B29C 66/1312 20130101; B29C 66/71 20130101;
B29K 2023/0633 20130101; B29K 2059/00 20130101; B29K 2023/065
20130101; B29K 2025/06 20130101; B29K 2023/12 20130101; B29K
2055/02 20130101; B29K 2027/06 20130101; B29K 2033/12 20130101 |
Class at
Publication: |
206/524.6 ;
156/272.8; 156/60; 428/34.1; 428/35.7 |
International
Class: |
B65D 85/84 20060101
B65D085/84; B32B 1/08 20060101 B32B001/08; B32B 37/14 20060101
B32B037/14; B32B 37/02 20060101 B32B037/02; B32B 37/06 20060101
B32B037/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 2001 |
DE |
10137054.7 |
Claims
1. A capsule welded by a method of sealing parts of a plastic
capsule to form a weld seam in an overlapping region of the parts
of the capsule, wherein the capsule comprises a capsule cap having
an open end and a capsule body having an open end and wherein the
capsule cap and capsule body are composed of a material which has a
permeation coefficient for steam of less than 10.sup.-13 kg/(msPa),
the method comprising: (a) holding the capsule cap and the capsule
body in a capsule holder comprising a first holding part and a
second holding part which can be guided synchronously with one
another, wherein the first holding part interlockingly surrounds
the capsule cap and the second holding part interlockingly
surrounds the capsule body; (b) closing the capsule holder holding
the capsule cap and the capsule body so that the open end of the
capsule cap and the open end of the capsule body form a sealed
cavity therebetween and form an overlapping region, wherein the
overlapping region is not covered by the capsule holder, to obtain
a closed capsule: and (c) welding the closed capsule using an
energy beam of hot gas or laser light on the overlapping region to
form the weld seam thereon, the method resulting in a capsule
having: in the overlapping region only, a weld seam formed by the
energy beam bringing the capsule material to its melting point;
and, in the rest of the capsule material not in the overlapping
region, no effect from being brought to its melting point by the
energy beam.
2. The capsule of claim 1, wherein the capsule contains a
medicament.
3. The capsule to claim 1, wherein the capsule contains a
medicament for inhalation.
4. The capsule of claim 1, wherein the weld is formed around the
entire circumference in the overlapping region.
5. The capsule of claim 1, wherein the weld is formed only in a
portion of the overlapping region.
6. The capsule of claim 1, wherein the overlapping region where the
weld is formed is less than 3 mm wide.
7. The capsule of claim 1, wherein the overlapping region where the
weld is formed is 0.5 mm to 1 mm wide.
8. The capsule of claim 1, wherein the capsule cap and capsule body
are composed of a material selected from the group consisting of:
polyethylene (low density), polyethylene (high density),
polystyrene, acrylonitrile-butadiene-styrene, polypropylene,
polymethylmethacrylate, polyvinylchloride, and polyoxymethylene,
each having a permeation coefficient for steam of less than
10.sup.-13 kg/(msPa).
9. The capsule of claim 1, wherein the capsule wall of the capsule
has a thickness of 0.05 mm to 0.5 mm.
10. The capsule of claim 1, wherein the length of the capsule is 8
mm to 30 mm.
11. The capsule of claim 1, wherein the length of the capsule is 13
mm to 17 mm.
12. The capsule of claim 1, wherein the diameter of the capsule is
4 mm to 7 mm.
13. The capsule of claim 1, wherein the capsule is welded by laser
light.
14. The capsule of claim 13, wherein the capsule material contains
a dye that absorbs the energy of the laser light.
15. The capsule of claim 1, wherein the capsule cap and capsule
body are composed of a material which has a permeation coefficient
for steam of less than 1.3.times.10.sup.-14 kg/(msPa).
16. The capsule of claim 1, wherein the capsule cap and capsule
body are composed of a material which has a permeation coefficient
for steam between 10.sup.-15 and 5.times.10.sup.-16 kg/(msPa).
17. The capsule of claim 1, wherein the capsule cap and capsule
body are composed of high density polyethylene having a density
between 950 kg/m.sup.3 and 1000 kg/m.sup.3, having a permeation
coefficient for steam of less than 10.sup.-13 kg/(msPa).
18. The capsule of claim 1, wherein the capsule contains a
medicament for inhalation and the capsule wall of the capsule has a
thickness of 0.05 mm to 0.5 mm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a new method of sealing
plastic capsules or inhalers, inhalation capsules thus produced,
and an apparatus which is specially adapted to carry out the
process according to the invention. The capsules produced by the
process according to the invention are disposable and preferably
contain a single dose of a pharmaceutical formulation in the form
of a powder or liquid intended to be administered by inhalation and
are suitable by their form and function for use in powder inhalers
or liquid nebulizers for producing aerosols. Aerosols thus produced
can be inhaled, for example, in order to administer a
pharmaceutical formulation to the lungs.
BACKGROUND OF THE INVENTION
[0002] Capsules containing pharmaceutical preparations are widely
used in the treatment and diagnosis of diseases. The capsules may
be administered orally or are used in specific medical devices such
as powder inhalers. As a rule, the capsules consist of two parts, a
capsule body (body) and a capsule cap (cap) which are pushed
telescopically into one another. However, multi-sectional capsules
are also known. The capsules generally consist of gelatine,
particularly hard gelatine. For some special purposes, the capsules
are occasionally made of water-soluble plastics which are easily
digested by the patient so that when administered orally the active
substance is released in certain sections of the gastrointestinal
tract. Some examples of various capsule materials are give
hereinafter.
[0003] EP 0460921 describes capsules consisting of chitosan and
starch, powdered cereal, oligosaccharides, methacrylic
acid-methylacrylate, methacrylic acid-ethylacrylate,
hydroxypropylmethylcellulose acetate, succinate, or phthalate. The
capsule material is characterized in that the contents are only
released in the large bowel.
[0004] GB 938828 discloses capsules for radioactive substances for
therapeutic or diagnostic use. The capsules consist of
water-soluble gelatine, methylcellulose, polyvinylalcohol, or
water-soluble non-toxic thermoplasts.
[0005] EP 0312760 describes a method of sealing hard gelatine or
starch capsules with a specific sealing agent. The seam in the
capsules may be displaced from the central plane of the
longitudinal axis of the capsule.
[0006] DE 3430764 discloses another method of sealing hard gelatine
capsules. In this method the capsules are first filled and the two
capsule halves are fitted together telescopically. Then, by lifting
the cap relative to the body of the capsule, a contact zone is
exposed on the capsule body, but the capsule must not be opened. In
a subsequent step, the contact zone is then made "tacky" so that
the cap can then be pushed back onto its original position and
brought into contact with the contact zone. This process requires
high precision when carrying it out particularly as it is important
to avoid deforming the capsule when the cap is pushed back onto the
capsule body which has been made tacky by heating and thereby been
made more prone to deformation. Page 32 of the application states
that tools with no tolerances or play of any kind are needed in
order to hold and guide the capsule sections.
[0007] U.S. Pat. No. 4,991,377 discloses another process for
sealing keratin or gelatine capsules. In this process, the sealed
capsule which consists of two telescopically connected sections is
treated with hot air at its weld seam. During the process, the
lower part of the capsule rests on a holder. The patent
specification does not give any hint as to how to avoid deformation
of the capsules softened by the blast of heat nor how to avoid
heating or carbonization of other parts of the capsule outside the
seam zone. Nor is there any mention of how the quality of the
contents of the capsule is affected by the heat produced by the
welding.
[0008] WO 00/07572 discloses capsules for inhalers of the kind
according to the invention which consist of indigestible plastic.
We hereby refer expressly to this patent document and the object
disclosed therein. The capsules described therein are sealed
analogously to standard commercial hard gelatine capsules, i.e.,
the capsule cap is placed telescopically on the capsule body. The
seam which is necessarily produced between the cap and the body may
optionally be welded, glued or banded to reduce the steam
permeability. Alternatively, the entire cap may be covered with a
continuous protective film or the gap in the seam may be filled
with a filler. There are no details of the methods of sealing the
cap, particularly no mention of any welding processes.
[0009] Various thermal welding methods are known from the prior art
for welding plastic materials. These include ultrasonic welding,
hot plate and hot tool welding, hot gas welding, rotary welding,
high frequency voltage welding, or induction welding.
[0010] By contrast, processes of this kind for sealing plastic
capsules for medicinal inhalers, which are subject to certain
limiting conditions with regard to their use, are not known.
[0011] It has now been found that these welding processes cannot
readily be transferred to the welding of the capsule halves
described in WO 00/07572.
[0012] The limiting conditions mentioned above, which prevent the
simple transfer of the methods known from the prior art to capsules
for inhalation, include the fact, for example, that the capsules
are filled with a pharmaceutical formulation the pharmaceutical
quality of which must not be impaired during the welding
process.
[0013] Another condition is laid down by the dimensions and
thickness of the capsules to be welded, particularly the thin walls
of such capsules. This is necessary to allow the capsule to be used
in a standard commercial inhaler analogously to the hard gelatine
capsules currently in common use. In fact, it has to be capable of
being opened easily. If the conventional methods are applied to
such a capsule, holes will rapidly be burnt into the capsule during
the welding process, particularly in those parts of the capsule
which are outside the area being welded. This area where the seam
is to be formed is naturally in a region where the walls of the two
parts to be joined together overlap. Next to this area there are
parts where there is no such overlap. In these parts, the capsule
can more easily be damaged by the welding process. There is also
the danger that if the capsule walls are too thick, any weld seam
at the junction will not be properly sealed.
DESCRIPTION OF THE INVENTION
[0014] The present invention is intended to provide sealed plastic
capsules for medicinal inhalation devices which contain a
pharmaceutical formulation. Preferably, these capsules contain a
single dose of the formulation. The capsules are also referred to
as single dose capsules within the context of the present
invention.
[0015] An inhaler which is preferred for the present purpose is
described, for example, in WO 94/28958 (HANDIHALER.RTM.) which is
hereby incorporated by reference in its entirety.
[0016] The present invention solves the problem described above by
providing a new welding method in which only the part of an
inhalation capsule to be welded is welded by means of an energy
beam in the form of a jet of hot gas or a laser beam. At the same
time, the capsule material is preferably warmed only at the
seam.
[0017] Thus, one aim of the invention is to provide a welding
process in which the parts of a plastic capsule which are not to be
welded are not heated to the melting point of the plastic.
[0018] A further aim is to provide a welding process for plastic
capsules in which the individual parts of a plastic capsule of this
kind for inhalers are firmly held together.
[0019] A further objective is to connect the individual parts of a
plastic capsule to one another so that they cannot be separated
again without damaging the capsule. This makes it easier for the
user to tell that the capsules have not already been opened.
[0020] A further aim is to provide a welding process for plastic
capsules in which there is no damage to the capsule caused by
overpressure produced in the capsule by the welding process, or any
such overpressure is minimized.
[0021] A further aim is to provide a welding process for plastic
capsules in which the pharmaceutical quality of the pharmaceutical
formulation in the capsule, which is a formulation for inhalation
according to the invention, is not jeopardized during welding.
[0022] A further aim of the invention is to weld the seam of
inhalation capsules of the kind described above on an industrial
scale under GMP (good manufacturing practice) conditions.
[0023] The capsules to be welded consist of non-water-soluble,
preferably water-repellent plastics which themselves do not
substantially affect the pharmaceutical quality of the contents but
which improve the usability of the filled capsules in terms of
their function, their period of use and/or the climatic region, and
which are advantageous at various stages from manufacture to
use.
[0024] The capsule according to the invention consists of at least
two parts, a capsule body (body) and at least one capsule cap
(cap), which are joined together in such a way as to form a stable
sealed cavity of a defined volume which contains the pharmaceutical
formulation. The dimensions of the capsule are such that it can be
used in common powder inhalers for capsules as described, for
example, in the patents DE 3345722 (Ingelheim M Inhaler), EP
0591136 (Ingelheim Inhaler), or in published German application DE
4318455 (HANDIHALER.RTM.). Size 3 capsules are particularly
preferred.
[0025] In one embodiment, the plastic of the capsule is
indigestible by humans so that if it is taken orally the active
substance is not released. The advantage of this is that accidental
swallowing of the capsule cannot lead to any lasting effects on
health. This applies particularly to small children or older
people.
[0026] Preferably, plastics are used which may be processed by
injection or blow molding and/or plastics which can be processed to
form the capsule cap or body without the use of any mold release
agents which may cause the contents to adhere to the walls of the
capsule. The advantage of this is that the inside of the cap or
body does not have to be cleaned to remove mold release agent in
order to conform to the official requirements (e.g., according to
DAB (Deutsches Arzneibuch) which restrict the use of mold release
agents for primary packaging. Thermoplasts which allow the halves
of the capsule to be welded together are preferred.
[0027] Preferred materials have the property of having as little
powder as possible, preferably no powder, adhering to them.
[0028] Suitable plastics for the process according to the invention
include polyethylene LD (low density), polyethylene HD (high
density), polystyrene, acrylonitrile-butadiene-styrene,
polypropylene, polymethylmethacrylate, polyvinyl chloride,
polyoxymethylene, polycarbonate, polyester, or polyethylene
terephthalate. In preferred embodiments, the plastic is
polyethylene, particularly polyethylene with a density of between
900 kg/m.sup.3 and 1000 kg/m.sup.3, preferably 960 kg/m.sup.3 (high
density polyethylene). In a preferred embodiment, the plastic has
no marked adhesion for pharmaceutical/chemical substances,
particularly for particles of a size capable of entering the lungs,
so that when the capsule is used in one of the inhalers described
above the entire contents of the capsule can be released. This has
the advantage of enabling a more accurate dosing, particularly of
the fine fraction destined for the lungs.
[0029] In another embodiment, the capsule consists of a plastic
with a Shore hardness D of 65 to 73. A plastic with this hardness
does not shatter when pierced or cut open but at the same time is
rigid enough so that the hole formed does not close up on its own.
The advantage of such a material is that no bits of the capsule can
be broken off during the opening, piercing or cutting open of the
capsule in the powder inhaler, which might then be breathed in
during inhalation.
[0030] In one embodiment, the plastic capsule is so stable that it
will withstand a force of up to 15 N along the longitudinal or
transverse axis. The advantage of this is that the capsule is
better adapted to the stresses which act on the capsule during
manufacture, filling, packaging, transporting and the like.
[0031] In another embodiment, the material of the capsule has a
permeation coefficient for steam of less than 10.sup.-13 kg/(msPa),
preferably less than 1.3.times.10.sup.-14 kg/(msPa). Preferably,
the coefficient is between 10.sup.-15 and 5.times.10.sup.-16
kg/(msPa), most preferably between 5.times.10.sup.-16 and
2.times.10.sup.-16 kg/(msPa). The advantage of this property is
that the contents of the capsule are protected from moisture even
in geographical zones with a high relative humidity.
[0032] The capsule according to the invention can be used in all
kinds of powder inhalers in which the preparation which is to be
inhaled is introduced by means of a capsule.
[0033] In a preferred embodiment, the cap and body of the capsule
are similarly cylindrical in shape, consisting of an inherently
closed casing with one closed and one open end. The shape and size
of the cap and capsule are such that the open end of the body can
be pushed telescopically into the open end of the cap so that the
cap is firmly attached to the body. In a preferred embodiment, the
cap and the body are in the form of a cylinder of circular
cross-section with a convex, virtually hemispherical, closed
underside and both consist of high density polyethylene with a
density of between 950 kg/m.sup.3 and 1000 kg/m.sup.3.
[0034] In a special embodiment, the cap and body are provided with
closure means which are advantageous for temporarily and/or finally
closing the capsule.
[0035] In one such embodiment, there may be dot-like elevations on
the inner surface of the cap and somewhat larger dot-shaped
depressions on the outer surface of the body, which are so arranged
that when the capsule is closed the elevations engage in the
depressions. Alternatively, the elevations may be provided on the
outer surface of the body and the depressions on the inner surface
of the cap. Arrangements in which the elevations or depressions are
arranged in rings or spirals around the casing are preferred.
Instead of the dot-like shape of the elevations and depressions,
these may also extend in a continuous ring around the surface of
the cap or body. The latter engagement means are preferred. One or
more encircling annular elevations are formed on the inner surface
of the cap and the outer surface of the body so that in the closed
position of the capsule an elevation on the cap is adjacent to an
elevation on the body in each case. In the embodiments with these
annular depressions and/or elevations, the latter may be continuous
or interrupted. In another embodiment, elevations are formed on the
outside of the body close to its open end and holes are formed in
the cap close to the open end so that the elevations on the body
engage in the holes in the cap in the closed position of the
capsule. The elevations may be such that the cap can be opened at
any time without damage to the capsule or so that once it has been
sealed the capsule cannot be opened again without destroying
it.
[0036] Capsules with one or more such engagement mechanisms
(detents), e.g., two encircling grooves, are preferred. Capsules
with at least two such engagement means which secure the two
capsule parts with different degrees of strength are particularly
preferred. In one such part, a first latching means may be provided
close to the openings of the cap and body and a second may be
provided somewhat closer to the closed end of the capsule parts.
The first engagement means secure the two capsule parts less
strongly than the second. The advantage of this embodiment is that
the cap and body of the capsule can be temporarily joined together
using the first engagement means before the capsule is filled.
Then, in order to fill the capsule, the two sections are separated
again. After filling, the two capsule parts are pushed together
until the second set of latching means firmly secure the capsule
sections.
[0037] In another embodiment, a bead is formed on the outside of
the body, running around the body perpendicular to the connecting
axis between the cap and body. The bead acts as a stop for the
capsule when the latter is pushed over the body to prevent impact
between the cap and the body. The region between the open end of
the body and the bead corresponds to the part of the body over
which the cap can be pushed. The bead is located on the body so
that the cap can be pushed far enough over the body to achieve a
firm seal between the cap and body. In other words, the bead is not
located right at the open end of the body, for example. The side of
the bead which points towards the open end of the body stands up as
a perpendicular edge on the outer wall of the body so that when the
capsule is closed the cap cannot be pushed beyond the bead. The
side of the bead facing the closed end of the body may take the
form of a virtually right-angled edge or may flatten out towards
the closed end of the body. The provision of a virtually
right-angled edge may be advantageous when the capsule is fitted
loosely in a capsule holder, while the variant with a bead that
flattens out is suitable for a firm fit of the capsule. The bead
may be continuous or interrupted.
[0038] In a preferred embodiment, the bead flattens out
continuously towards the closed end of the body and stands on the
capsule body with its side oriented towards the open end of the
body in a perpendicular position. The height of the edge thus
formed is such that in the closed state of the capsule the edge
does not project beyond the cap, with the result that the
transition from the cap to the body is smooth.
[0039] Alternatively, instead of the bead, the diameter of the
capsule body may be abruptly reduced at one point so that the
diameter oriented towards the opening is smaller (or larger) than
the diameter oriented towards the closed end of the body. The cap
and body may be constructed so that in the closed state the capsule
is smooth at the seam.
[0040] In another alternative, the shape of the wall of the cap in
the opening region is precisely the reverse of the shape of the
wall of the opening of the capsule. In other words, the wall of the
capsule widens out in the region of the opening to form an internal
edge. In this embodiment, too, the outer casing is preferably
smooth. In this embodiment, the cap is pushed onto the capsule
until the edge of the cap and the edge of the capsule make contact
with each other.
[0041] In another preferred embodiment, the bead is located on the
inside of the capsule body. The edge of the bead on which the cap
rests in the closed position of the cap then faces the outside of
the capsule body. In such a case, the cap is not fitted onto the
capsule body but inserted in the capsule body. The cap and body may
be constructed so that in the closed state the capsule is smooth at
its seam. Within the scope of the present invention the two
possible methods of fitting the capsule cap over or into the
capsule body are described as being of equal value, i.e., wherever
one of the two possibilities is described, the other is also
applicable.
[0042] In another embodiment, the edge of the capsule body is in
the form of a U-shaped return in which the edge of the opening of
the capsule cap is inserted. In another embodiment, both openings
have a U-shaped return of this kind. In yet another embodiment, the
edge of the openings of the cap and body widen out and are smooth
in the direction pointing towards the opening.
[0043] The thickness of the walls of the cap and body may vary over
the entire region. Thus, the wall thickness is generally greater in
the rounded parts of the cap or body or at the point on the body
where the bead is formed, than in the areas where the walls extend
in a straight line. In one embodiment, the walls of the cap and
body have a thickness of 0.1 mm to 0.5 mm, the capsule preferably
having a mean thickness of 0.1 mm to 0.4 mm, more preferably 0.2 mm
to 0.4 mm.
[0044] The capsule body has a thickness of 0.15 mm to 0.35 mm,
preferably 0.225 mm to 0.275 mm, most preferably 0.25 mm in the
region of its opening, particularly at its edge.
[0045] The capsule cap has a thickness of 0.25 mm to 0.45 mm,
preferably 0.325 mm to 0.375 mm, most preferably 0.35 mm, in the
region of its opening, particularly at its edge.
[0046] The length of the capsule is 8 mm to 30 mm, preferably 13 mm
to 17 mm, most preferably 15.5 mm to 16 mm. The diameter of the
capsule is 4 mm to 7 mm, preferably 5.3 mm to 6.3 mm. A diameter of
5.75 mm to 5.95 mm is particularly preferred.
[0047] A preferred capsule is 15.9 mm long, with a body 5.57 mm in
diameter and a cap 5.83 mm in diameter. The preferred wall
thickness of the capsule body is 0.25 mm and that of the cap is
0.35 mm.
[0048] In one possible embodiment, bumps are formed on the outside
of the capsule while in another embodiment three or more ribs are
provided extending parallel to the longitudinal axis of the
capsule. The advantage of these arrangements is that the capsule
can be removed from a capsule holder, as used, for example, in the
powder inhalers mentioned above, in such a way that it is not
damaged or pulled open. The ribs or bumps may extend over the
entire outer surface of the capsule or may cover only a part of it.
Alternatively, they may be formed only on the cap or only in that
part of the body which is outwardly visible in the closed state.
The ribs run parallel to the longitudinal axis of the capsule and
ensure that the capsule is fixed vertically in said capsule holder.
In the case of a capsule of circular cross-section, the ribs are
preferably arranged so that the cross-section of the capsule is not
rotationally symmetrical about the central axis. In such an
embodiment, the ribs may be formed only in that part of the body
which is visible in the closed state of the capsule. This
embodiment prevents the capsule from becoming jammed in a capsule
holder.
[0049] In an embodiment without a bead but with ribs on the part of
the body which is visible in the closed position of the cap, the
ribs are formed so that the ends of the ribs oriented towards the
open end of the body perform the same function as the bead, namely
to act as a stop for the cap when the cap is combined with the
body.
[0050] In another embodiment, the outer surfaces of the cap and
body describe a hollow cylinder of round, oval, triangular,
rectangular, hexagonal, octagonal, or polygonal cross-section, in
which the top is open and the bottom is closed in each case. The
closed underside may be flat or convex. The angular embodiments
have the advantage that they can be stored more compactly than the
round ones.
[0051] In one embodiment, the elongation of the capsule (distance
from the closed end of the body to the closed end of the cap in
relation to the diameter when the capsule is closed) is greater
than 1, in another embodiment the elongation is equal to 1, and in
yet another embodiment the elongation is less than 1. The advantage
of the latter is that the body has a larger opening for filling it
up. In one of the embodiments with an elongation equal to 1, the
cap and body are such that the closed capsule is spherical in
shape, which may be advantageous for automatically loading a powder
inhaler with the capsule from a reservoir.
[0052] The description shows that the capsule according to the
invention is particularly suitable for holding powdered
pharmaceutical formulation of any kind suitable for inhalation. In
one particular embodiment, the capsule contains as active substance
cromoglycic acid, reproterol, beclomethasone, terbutalin,
salbutamol, salmeterol, ketotifen, orciprenaline, fluticasone,
insulin, ipratropium, tiotropium, dexamethasone, bambuterol,
tiotropium, budesonide, fenoterol, clenbuterol, prednisolone,
prednisone, prednylidene, methylprednisolone, formoterol, or
nedocromil, the pharmacologically acceptable salts or mixtures
thereof, or another cortisone preparation or atropine derivative
suitable for inhalation.
[0053] In a preferred embodiment, the capsule contains ipratropium
bromide or tiotropium bromide.
[0054] Apart from powder fillings, the welded capsules may also
hold liquids and are then suitable for the latest liquid
inhalers.
[0055] The sealing of the minimum of two telescopically fitting
sections of the capsule is preferably done using a process in which
a locally tightly restricted stream of energy consisting of hot gas
or laser light is guided in a relative movement at least once
around the perpendicular axis of the overlapping area of the
capsule elements so that in this area the capsule material is
melted but not destroyed and a weld seam is produced in this
area.
[0056] The rotary movement can either be produced by rotating the
capsule about its axis, perpendicular to the plane of the weld
seam, in the beam of energy or by guiding the beam of energy around
the capsule.
[0057] The capsule seam is then welded within one revolution or
several revolutions.
[0058] Welding processes in which the welded seam of capsule
material is produced within several revolutions are preferred as
this allows better control of the welding process. For example,
this will prevent holes from being burnt into the capsule wall.
[0059] Preferably, in the process according to the invention, hot
gas and laser light are used as the energy sources. If laser light
is used, the thermal energy required for welding is induced in the
capsule material by absorption.
[0060] The welding process itself may take place either directly at
the seam between the two capsule sections or in the overlap between
the two capsule halves.
[0061] The weld seam thus formed is produced as one or more
continuous lines along the circumference of the capsule parallel to
and between the two planes which span the openings of the cap and
the body. Preferably, the seam is tightly sealed all round by means
of the process according to the invention.
[0062] In addition to closed lines forming, the weld seam it is
also possible to use spiral lines. However, the configuration of
the weld seams is not restricted to straight shapes but may also
include zigzags or meandering lines or any other shape running
around the exterior of the capsule. The weld seam may also be in
the form of spot welds.
[0063] Preferably, the weld seam is formed at a point where the
capsule body and cap are just beginning to overlap. Depending on
the method used, a number of weld seams may be provided. These may
be formed parallel to one another, for example.
[0064] In multi-sectional capsules, weld seams are needed at all
the connecting points to achieve the required stability and seal.
In two-part and multi-part capsules, a plurality of adjacent weld
seams increases the reliability of the seal.
[0065] Depending on the size of the capsule body and cap, the
position of the weld seams may be located centrally with respect to
the longitudinal axis. However, an asymmetric position is preferred
in order to obtain the maximum possible spacing from the capsule
contents.
[0066] This may also be achieved, for example, if either the
capsule body is longer than the capsule cap or vice versa. In this
context, the term length denotes the distance between the opening
of each of the two capsule halves and the opposite closed side.
Preferably, the seam is located in the top third of the closed
capsule. This means that the proportion of the capsule from the
closed base to the point where the above-mentioned bead is formed,
which marks the point up to which the open end of the capsule cap
is pushed over the opening of the capsule body onto said body, is
about two thirds of the total length of the sealed capsule.
[0067] A capsule of this kind has the advantage that the fill
height of the formulation within the capsule can be below the seam,
so that the danger of impairing the quality of the formulation by
the welding process is significantly reduced.
[0068] The fill level of the capsule may be adapted to suit the
welding temperature and the temperature sensitivity of the
pharmaceutical formulation.
[0069] The present invention therefore also relates to a plastic
capsule of this kind with its weld seam positioned asymmetrically.
The other characteristics of the capsule according to the invention
were described in detail at the beginning.
[0070] The use of a measuring device makes it possible to judge the
welding temperature and the flow characteristics of the capsule
material during the welding process and hence to control the
process. The welding process preferably takes place with feedback
of the data from the measuring device in order to achieve a
constantly high quality for the weld seam. In this way it is
possible to ensure a uniform influx of energy at the weld seam.
[0071] The feedback balances out any fluctuations in the thickness
of the material, for example, and any environmental influences by
adjusting the speed of rotation of the relative rotation or the
energy supplied. In this context, it is preferable to melt as small
an area as possible and to measure the temperature or radiation
precisely at this point. The weld seam is then produced by
rotation.
[0072] In the process according to the invention, the energy
supplied and the relative speed of rotation are preferably adapted
to one another so that the capsule material is brought to the point
where it is just beginning to melt. By repeating this process once
or a number of times, a weld seam formed from the material is
produced.
[0073] The following are the temperatures required to bring the
preferred capsule materials to the point where they are beginning
to melt, although the examples must not be interpreted as
restricting the materials.
TABLE-US-00001 Material Processing Temperature Polyethylene LD
160.degree. C.-260.degree. C. Polyethylene HD 260.degree.
C.-300.degree. C. Polystyrene 170.degree. C.-280.degree. C.
Acrylonitrile-Butadiene-Styrene 210.degree. C.-275.degree. C.
Polypropylene 250.degree. C.-270.degree. C. Polymethylmethacrylate
210.degree. C.-240.degree. C. Polyvinylchloride 170.degree.
C.-210.degree. C. Polyoxymethylene 200.degree. C.-210.degree.
C.
[0074] In accordance with the melting temperature, the beam of
energy, its distance from the capsule surface, and its mean delay
time on the surface of the capsule are adjusted so that the capsule
material is melted without any holes being burnt in the capsule
wall.
[0075] The speed of rotation of the energy beam around the capsule,
or of the capsule in the energy beam, may be between 0.01
revolutions per second and a maximum of 40 revolutions per second.
In the case of laser welding it is preferably 0.1 to 20 revolutions
per second while in the case of hot gas welding it is preferably
0.2 to 2 revolutions per second.
[0076] This results in a circumferential speed of the preferred
capsule, with a length of 15.9 mm and a cap diameter of 5.83 mm and
a body diameter of 5.57 mm, of about 0.18 mm per second up to 732
mm per second. In the laser welding process, the circumferential
speed is preferably 1.8 mm per second to 366 mm per second, and in
the case of hot gas welding, it is 3.7 mm to 37 mm per second.
[0077] The number of revolutions of the capsule/energy beam may be
up to 40 for one welding process, preferably up to 20. In laser
welding, it is preferably 2 to 3 and in hot gas welding it is 5 to
8.
[0078] In the welding process according to the invention, the
capsules and the energy source are preferably brought together at a
specific speed of advance. Speeds of advance of 0.1 cm per second
to 10 cm per second are preferred, whilst a speed of advance of 1
cm per second to 5 cm per second is particularly preferred.
[0079] Using the process according to the invention, the capsules
can be welded in a cycle time of preferably less than 10 seconds.
Processes in which the capsules are welded within 5 seconds are
more preferred, while processes in which welding takes place within
1 second are even more preferred.
[0080] Thus, a further advantage of the process according to the
invention is achieved: the short welding duration avoids the
formation of bubbles caused by the heating of the gas enclosed in
the capsule.
[0081] The capsules produced by the process according to the
invention preferably have an axis of symmetry C.sub.n (where n is
the symmetry number) and a plane of symmetry which is ideally
perpendicular thereto. This latter criterion is restricted to
cylindrical capsules whose weld seam is central in relation to the
longitudinal axis. Rotationally symmetrical capsules are
particularly preferred.
[0082] It is not essential for the circumference of the capsules to
be circular. The circumference may also be polygonal or
elliptical.
[0083] The preferred external shape of the capsule is smooth.
Plastic capsules according to published German application DE 198
35 346 A1 are particularly preferred.
[0084] In the case of laser welding and embodiments of the capsules
with a polygonal or elliptical cross-section, the capsule seams are
either irradiated with an average dose at an average working
distance with an unfocused beam or preferably with an active beam
adjustment, the focus following the rotation synchronously in
accordance with the geometry of the capsule, or most preferably,
with intensity regulation which equalizes any loss of focus by
increasing the power.
[0085] Before the actual welding process, preparatory measures have
to be taken. These are necessary in order to take account of
welding requirements regarding the energy source used, the
construction of the capsules from a geometric point of view, and
the choice of material as well as the choice of additives, e.g.,
dyes, which may be added to one or more parts of the capsule. Dyes
are preferably used in laser welding.
[0086] The advantage of having the dyes in the plastic is that the
dyes absorb the laser light in the plastic and thereby heat up the
plastic locally to cause the material to fuse.
[0087] The dyes used are adjusted to the frequency of the laser
light and the quantity of heat required.
[0088] The dyes used are those which will not affect the
pharmaceutical quality of the formulation in the capsule.
Preferably, food colorings are used.
[0089] Examples of particularly preferred dyes are:
TABLE-US-00002 Dye Color Iron Oxide Red = E 172 = Fe.sub.2O.sub.3
red FD&C Red 3 = E 127 =
C.sub.20H.sub.6I.sub.4O.sub.5Na.sub.2.cndot.H.sub.2O = Erythrosine
red beta-carotene = E 160a = C.sub.40H.sub.56 yellow Iron Oxide
Yellow = E 172 = FeO(OH) yellow FD&C Blue 2 = E 132 =
C.sub.16H.sub.8N.sub.2O.sub.8S.sub.2Na.sub.2 = Indigotine blue
Chlorophylline = E 141 = C.sub.34H.sub.31N.sub.4O.sub.6CuNa.sub.3
or green C.sub.34H.sub.31N.sub.4O.sub.6CuK.sub.3 Caramel = E 150a
or E 150d = "burnt" sugar beige Titanium dioxide = E171 white
[0090] Of these, the inorganic pigments are particularly
preferred.
[0091] The additives may either be applied to the finished capsule
sections (e.g., by spraying, printing, painting or dipping) and
then be fused on during the welding process or they may be
incorporated in the capsule material during the manufacture of the
capsules, by a masterbatch method.
[0092] In laser welding, the circumference has to be totally
irradiated to ensure that the entire circumference of the capsule
is fully welded. It is possible to use a linear optical device
which welds the entire circumference simultaneously. Preferably,
the capsule and light beam are moved relative to each other and as
a result the focal spot is guided along the circumference of the
capsule. This may be done, for example, by rotating the capsule in
the light beam of the laser.
[0093] Alternatively, the laser beam may be guided around the
capsule by means of rotating mirrors. Relative rotation of the
capsule and laser beam by means of a holder which allows the angle
of rotation and laser activity to be synchronized is particularly
preferred.
[0094] Preferably, a radiation measuring device is used in laser
welding as a measuring device for feedback control of the welding
apparatus.
[0095] The feedback equalizes any fluctuations, e.g., in the
thickness of the material, its reflectivity, or the focusing and
other environmental influences by adjusting either the speed of
rotation or preferably the laser output. In this context, it is
preferable to melt the smallest possible spot of seam material
while measuring the temperature or radiation. The weld seam is then
produced by relative rotation of the capsule around the laser beam
as described above.
[0096] The laser power required for welding depends on the optical
device used (the size of the focal spot), the speed of advance, the
surface quality of the material (e.g., its roughness), the optical
qualities of the material (e.g., transparency), and the necessary
melting temperature of the materials. For example, green plastic
capsules were welded with a 5 Watt argon ion laser beam (wavelength
all line, 514 nm and 488 nm), focusing was done with a microscope
lens (magnification 10.times.). The same capsules could also be
welded using an infra-red laser (wavelength around 900 nm) with a
radiation output of about 100 Watts.
[0097] Using the laser welding process according to the invention,
the weld seam can be produced either immediately or during the
second or even subsequent repeat irradiations. When the process is
repeated, the capsule and light source are preferably rotated
relative to another so that the point which has been irradiated
once has not yet cooled down again when it meets the laser beam
again. The focus of the laser beam is preferably selected to be
precisely the right size to generate only a little heat on the
inside of the capsule wall and localized on the seam of the
capsule.
[0098] The width of the weld seam can be adjusted by a rapid
oscillating movement of the focal spot in directions other than the
direction of advance of the welding. Preferably, the width is
adjusted by optically imaging the laser radiation on a focal spot
preferably less than 1 mm in size. A focal spot diameter of less
than 0.5 mm is particularly preferred.
[0099] In hot gas welding, the total welding of the entire
circumference of the capsule requires that the capsule be heated
uniformly around its circumference. This can be achieved by the use
of one or more nozzles which may be crescent-shaped or annular, for
example, which simultaneously weld the entire circumference.
However, relative movement of the capsule and a flat beam generated
by a corresponding nozzle with a flat rectangular opening is
preferred. The melting zone thus produced can then be guided around
the circumference of the capsule until the weld is complete. It is
particularly preferred to rotate the capsule by means of a holder
which allows synchronization between the angle of rotation and the
influx of hot gas.
[0100] When producing individual capsules it is advantageous to use
one nozzle or a plurality of nozzles with a small cross-section.
For industrial mass production, one (or two) long slotted nozzles
should be used and a plurality of capsules are guided past said
nozzle or nozzles all at once with continuous rotation.
[0101] In the case of hot gas welding, crescent-shaped slotted
nozzles may advantageously be used if the process involves rotating
the capsules in the hot stream of gas.
[0102] The dimensions of the slots of the nozzle are designed so
that a flow of heat is obtained which is very restricted in its
height. Preferably, the height of the slot opening is up to 3 mm,
preferably up to 2 mm, most preferably up to 1 mm. The length of
the opening is variable. In the case of non-radial weld seams, the
length like the height should be restricted to 3 mm, preferably 2
mm, most preferably 1 mm. In the case of weld seams running
radially or spirally around the capsule, the length of the nozzle
slot is of less importance.
[0103] The height of the weld seam is determined by the height of
the nozzle jet. In the case of a weld seam running radially around
the capsule, the region of the capsule on which the weld seam is to
be formed runs parallel to the longitudinal side of the nozzle
arrangement in the energy flow. The length of the nozzle
arrangement and the temperature of the energy flow together with
the melting point of the capsule material determine the retention
time of the capsule in the energy beam. In other words, the longer
the nozzle opening and the hotter the energy beam the faster the
capsule has to be rotated parallel to this direction. In other
words, the weld seam around the capsule extends parallel to the
length of the nozzle arrangement.
[0104] In such cases, the length of the slotted nozzle may be
several centimeters or may even run into meters. An elongated
slotted nozzle of this kind is particularly advantageous if a
plurality of capsules are to be welded one after another on a
conveyor belt.
[0105] The process according to the invention is perfectly
controlled so that the weld seam is not produced immediately but
only on the second or subsequent repeat exposure to the hot gas.
This repetition is preferably achieved by rotating the capsule and
hot gas nozzle relative to one another before the heated point has
cooled down again.
[0106] The temperature of the gas required for welding depends on
the melting ranges of the plastics used and their distance from the
hot gas nozzle. However, in order to apply the narrowest possible
jet of heating gas to the seam, the capsule is moved past the
nozzle at a very short distance from it, preferably at a distance
of 5 mm.
[0107] The width of the hot gas jet on the weld point is 1 mm to 2
mm.
[0108] In another aspect, the present invention relates, in
addition to the welding process and the capsule thus obtained, to a
capsule holder adapted to the welding process.
[0109] The capsule holder according to the invention consists of
two separate molds the inner configuration of which is dish-shaped.
The dish-shaped mold is constructed so that one mold holds the
capsule body tightly while the other holds the cap, and in the
closed state only the seam area which is to be welded is not
covered by the holder.
[0110] The advantage of this arrangement is that only the area of
the capsule to be welded is able to come into contact with the
energy beam and the other areas of the capsule are protected from
the beam.
[0111] Preferably up to 3 mm and most preferably 0.5 mm to 1 mm of
the edge of the capsule half which is to provide the seam is left
exposed.
[0112] The outer shape of the holder is unimportant but it must
allow the hot gas to flow away. For example, the two parts of the
holder may be cylindrical in shape.
[0113] The top part and bottom part of the capsule holder are
joined together so that the position of the tools is maintained
even when the connection between the individual parts is just
beginning to melt, without exposing the capsule to any torsion or
tension. This is particularly important for the welding process if
the dimensional stability of the capsule is reduced by heating up a
partial region.
[0114] The purpose of the capsule holders is to hold the capsules
and guide them past the energy source for the welding process. At
the same time, they serve to cool the areas of the capsule walls
which are not to be welded and thus also protect the formulation in
the capsule.
[0115] So as to protect the formulation from the conditions of the
welding process, the fill level of the capsule is preferably below
the weld seam, in the protected area.
[0116] The capsule holders may be constructed so as to cool the
capsules. Systems with water cooling or Peltier elements may be
suitable for this, for example.
[0117] The capsule holder may be made of metal, e.g., aluminium,
copper, or stainless steel, or heat resistant plastics, e.g.,
polytetrafluoroethylene (Teflon.RTM.).
[0118] Preferably, at least part of the two halves of the capsule
holder is connected to a rotating device so that the capsule can be
rotated about the energy source. Preferably, the capsule holder
rotates about its own axis which is spanned by the top and bottom
parts of the holder.
[0119] A plurality of capsule holders may be arranged on one
conveyor, preferably in a row. In this case, the holder for the
capsule body is connected to a conveyor. Over it and parallel
thereto runs a second conveyor to which the holder for the capsule
cap is attached so that each capsule with its body is located in
the holder provided and the capsule cap is located in the holder
provided for it. The conveyors are constructed so that the two
halves of the capsule holders can be moved apart after the welding
so that the capsules are left behind in one of the two halves,
preferably the one for the original capsule body. This may be done,
for example, by having the conveyors consist of conveyor belts
which diverge after the welding station, initially in the same
plane. After that, the capsules can be removed from the holder.
[0120] In another embodiment, the holders may be attached to the
conveyor by a telescopically extendable arm. These arms are
extended towards the other arm in each case when the capsule is
welded so that the capsule is protected by the two extremities of
the holder in a manner described above. After the welding process,
the arms are retracted again so that the two halves of the holder
are moved apart.
[0121] In this way, the capsules can be brought up to the energy
source.
[0122] Preferably, the holders are mounted so as to be rotatable
about themselves on the conveyor.
[0123] As soon as the capsule has been conveyed into the energy
beam, the capsule holder as a whole rotates about itself and
thereby rotates the capsule in the energy beam so that the weld
seam is formed all around the capsule.
[0124] In the case of capsule holders which are not rotatably
mounted, the energy beam may be moved around the capsule
accordingly.
[0125] During the welding, an overpressure is produced by the
heating in the capsule. This pressure constitutes a considerable
risk, as it may lead to the formation of bubbles in the heated wall
of the capsule if the capsule is heated excessively. The capsule
holder according to the invention also advantageously provides a
remedy to this source of danger.
[0126] Additionally, the capsule holder also protects the parts of
the capsule which are not to be welded and the formulation in the
capsule.
[0127] The process according to the invention produces capsules
containing pharmaceutical compositions for inhalers, which are
totally sealed so that the pharmaceutical substance cannot escape
from the capsule unless the capsule is destroyed.
[0128] The advantage of the capsules according to the invention is
that they have a very low steam permeability, particularly at the
seam, and are therefore suitable for use in various climatic
regions, e.g., in climatic region 3 with a high relative humidity,
without any impairment of the pharmaceutical quality of the
formulation. These capsules also have various advantages at other
stages of the life of the capsule from its manufacture to its use,
in terms of its usability as a carrier of pharmaceutical
preparations, the method of administering the contents, the
durability of the contents, and/or the suitability of the capsules
for use in various countries. One other advantage of the capsule
materials according to the invention is that they do not have a
tendency to bind powdered materials to themselves, so that precise
metering of the fine fraction destined for the lungs is made
easier.
[0129] These capsules may also be used in non-medicinal
aerosols.
BRIEF DESCRIPTION OF THE FIGURES
[0130] The Figures show various embodiments of the capsules
according to the invention by way of example but are provided
solely as an illustration without restricting the scope of the
invention.
[0131] FIG. 1 shows the simplest and most preferred embodiment of
the capsule according to the invention in lateral
cross-section.
[0132] FIGS. 2a and 2b each show a different embodiment of the
capsule with a tapering bead on the body in lateral
cross-section.
[0133] FIG. 3 shows an embodiment of the capsule with an
edge-shaped bead on the body in lateral cross-section.
[0134] FIG. 4 shows an embodiment of the capsule with a tapering
bead on the body and an annular recess on the body and cap in
lateral cross-section.
[0135] FIG. 5 shows an embodiment of the capsule with a tapering
bead on the body and an annular recess on the body and cap in front
view.
[0136] FIG. 6 shows an embodiment of the capsule with a tapering
bead on the body and dot-shaped recesses or elevations on the body
and cap in front view.
[0137] FIG. 7 shows an embodiment of the capsule with a tapering
bead on the body and dot-shaped elevations on the body and
dot-shaped holes in the cap in front view.
[0138] FIG. 8 shows an embodiment of the capsule with ribs on the
body in front view.
[0139] FIG. 9 shows the capsule of FIG. 7 in horizontal
cross-section.
[0140] FIGS. 10a, 10b, and 10c show embodiments of the capsule with
different cross-sections.
[0141] FIGS. 11a to 11g show different embodiment of capsules 1
with non-centrally arranged closure points between the cap and the
body to form the weld seam 13.
[0142] FIGS. 12a to 12i show capsules with various forms of weld
seam (straight, spiral, meandering, zigzag, spot welds, or parallel
diagonally extending non-continuous weld seams).
[0143] FIG. 13 shows a capsule holder.
[0144] FIG. 14 shows a capsule holder in the energy beam of a
laser.
[0145] FIG. 15 shows a capsule holder with a capsule around which
the laser beam is guided.
[0146] FIG. 16 shows a capsule holder in the energy beam of a hot
gas nozzle.
[0147] FIG. 17 shows a capsule in which the seam between the cap 2
and body 3 is formed perpendicular to the longitudinal axis of the
capsule.
[0148] FIG. 18 shows a capsule consisting of two caps 2 and a body
3.
[0149] An embodiment with a spherical capsule is not shown. FIG. 1
shows the simplest embodiment of the capsule 1 according to the
invention, in cross-section. The capsule 1 consists of the cap 2
and the body 3 which are fitted telescopically one inside the
other.
[0150] The cap 2 and body 3 are of the same configuration and each
have a convex underside 4. FIG. 2a shows a cross-section through an
embodiment in which a bead 5 is formed on the body 3 of the capsule
1; this bead tapers towards the closed end of the body. With its
side oriented towards the open end of the body, the bead 5 stands
virtually perpendicularly on the body. The edge thus formed limits
the part of the body over which the cap 2 can be telescopically
pushed. Another embodiment is shown in FIG. 2b. The cross-section
shows that this embodiment differs from the one shown in FIG. 2a in
that the wall thickness of the cap 2 or body 3 is not the same over
the entire area but varies over individual sections. In addition,
the convex undersides 4 of the cap or body each have a concave
indentation at the apex.
[0151] FIG. 3 shows an embodiment in which the bead 5 rests more or
less at right angles to the body, both towards the top of the body
and towards its underside.
[0152] The embodiment in FIG. 4 is a further development of the
embodiment in FIG. 2a in which an annular recess 6 or 7 is formed
in the cap 2 or body 3 to improve the closure of the capsule 1.
[0153] FIG. 5 shows a front view of the embodiment shown in
cross-section in FIG. 4.
[0154] FIG. 6 shows another variant of the invention with
dot-shaped depressions 8 and 9, in front view.
[0155] FIG. 7 shows an alternative form of the capsule 1 in which
elevations 10 are formed on the body 3 near the open end and holes
11 are formed in the cap 2 near the open end so that the elevations
10 is engaged in the holes 11 when the capsule is closed.
[0156] FIG. 8 shows an embodiment of the capsule 1 viewed from
outside, wherein the ribs 12 are formed on the body 3.
[0157] FIG. 9 shows the body 3 of the embodiment shown in
cross-section in FIG. 7. The cross-section shows that the three
ribs 12 are not rotationally symmetrical about the central axis of
the body. FIG. 10a shows a capsule 1 of rectangular cross-section
while FIG. 10b shows one with a triangular cross-section and FIG.
10c shows one with an octagonal cross-section.
[0158] FIGS. 11a to 11g show various embodiments of capsules 1 with
non-centrally arranged closures between the cap and the body to
form the weld seam 13.
[0159] FIG. 11a shows a closure in which an inwardly offset edge 5
is formed on the outside of the body and an outwardly directed edge
5 is formed on the inside of the cap. The connection is reinforced
by a detent, preferably two detents. FIG. 11b shows an embodiment
in which only the body has an inwardly offset edge 5. The cap and
body adjoin one another smoothly. FIG. 11c shows an embodiment in
which an inwardly offset edge 5 is formed only on the cap. The body
does not have this feature. The cap and body adjoin one another
smoothly. FIG. 11d shows an analogous embodiment in which, in the
overlapping area of the cap and body, one or more bumps and one or
more depressions corresponding to them is or are formed on the
counterpart in order to achieve a better temporary closure before
welding. FIG. 11e shows an embodiment in which the closure is such
that the body does not have any closure features, the cap has a
U-shaped return 21 at its open end which can be fitted over the
open edge of the wall of the body. FIGS. 11f and 11g show
embodiments in which the thickness of the walls thicken the open
ends 22 of the body and cap in order to produce a wider contact
zone in the closure region between the two capsule halves.
[0160] FIGS. 12a to 12i show capsules 1 with various forms of weld
seam 13: 12a, 12c, and 12d being straight, 12e being spot welds,
12f being zigzag-shaped, 12g and 12h being parallel, diagonally
extending, non-continuous weld seams, and 12b and 12i being
spiral-shaped.
[0161] FIG. 13 shows a capsule holder 14 consisting of the holder
15 for the capsule body 3 and a holder 16 for the capsule cap
2.
[0162] FIG. 14 shows a capsule holder 14 in the energy beam 18 of a
laser 17.
[0163] FIG. 15 shows a capsule holder 14 with a capsule 1 around
which the laser beam 18 is guided by means of two mirrors 19.
[0164] FIG. 16 shows a capsule holder 14 in the energy beam of a
hot gas nozzle 20. The nozzle may also be wider so that a plurality
of capsules in a row can be moved past the slot-shaped nozzle at
the same time.
[0165] FIG. 17 shows a capsule in which the seam between the cap 2
and body 3 is formed perpendicularly to the longitudinal axis of
the capsule.
[0166] FIG. 18 shows a capsule consisting of two caps 2 and a body
3. In this case a body is a tube open on two sides, each opening
being closed off by a cap 2.
[0167] In all the embodiments, the features described for closing
the capsule with regard to the cap and body may also be arranged
reciprocally, i.e., the closure features located on the cap may be
provided on the body and vice versa.
EXAMPLES
[0168] Typical operating data for hot air blowers: Steinel hot air
blower 1800 W, electronically regulated. Special nozzle with nozzle
opening 1 mm.times.7 mm, hot air temperature about 250.degree. C.
at the nozzle outlet. Rotation of the capsule by stepping motor
slower than 3 revolutions per second at a distance of 10 mm.
[0169] Operating data for lasers: The operating data are determined
by the particular laser used. A rate of 0.75 seconds per capsule is
achieved with a light output of about 30 Watts.
[0170] The average retention time at a welding station is
approximately 22 milliseconds in the case of laser welding with a
focal spot 0.1 mm in diameter, if the capsule performs 2
revolutions within 8 seconds, corresponding to a circumferential
speed of 4.6 mm per second. A capsule 15.9 mm long with a body 5.57
mm in diameter and a cap 5.83 mm in diameter was used, the wall
thickness of the capsule body being 0.25 mm and that of the cap
being 0.35 mm.
[0171] In the case of a 1.5 Watt argon ion laser, a green capsule
is used.
[0172] In hot gas welding, an average retention time of about 0.26
seconds is obtained for the same capsule if a jet of hot air about
1 mm high and 7 mm wide is used and the capsule is rotated 12 times
in the jet within 8 seconds. The speed at the capsule circumference
is then about 27 mm per second.
Examples of Capsules
[0173] Length of capsule bodies: 22.2.+-.0.46 mm; 20.22.+-.0.46 mm;
20.98.+-.0.46 mm; 18.4.+-.0.46 mm; 16.61.+-.0.46 mm; 15.27.+-.0.46
mm; 13.59.+-.0.46 mm; 12.19.+-.0.46 mm; 9.3.+-.0.46 mm.
[0174] Length of capsule cap: 12.95.+-.0.46 mm; 11.74.+-.0.46 mm;
11.99.+-.0.46 mm; 10.72.+-.0.46 mm; 9.78.+-.0.46 mm; 8.94.+-.0.46
mm; 8.08.+-.0.46 mm; 7.21.+-.0.46 mm; 6.2.+-.0.46 mm.
[0175] External diameter of capsule bodies: 9.55 mm; 8.18 mm; 7.36
mm; 7.34 mm; 6.63 mm; 6.07 mm; 5.57 mm; 5.05 mm; 4.68 mm.
[0176] External diameter of capsule caps: 9.91 mm; 8.53 mm; 7.66
mm; 7.64 mm; 6.91 mm; 6.35 mm; 5.83 mm; 5.32 mm; 4.91 mm.
[0177] Total length of sealed capsule: 26.1.+-.0.3 mm; 23.3.+-.0.3
mm; 24.2.+-.0.3 mm; 21.7.+-.0.3 mm; 19.4.+-.0.3 mm; 18.0.+-.0.3 mm;
15.9.+-.0.3 mm; 14.3.+-.0.3 mm; 11.1.+-.0.3 mm.
[0178] Capsule volumes: 1.37 mL; 0.95 mL; 0.78 mL; 0.50 mL; 0.37
mL; 0.30 mL; 0.21 mL; 0.13 mL.
[0179] Weight of capsules: 163 mg; 118 mg; 110 mg; 96 mg; 76 mg; 61
mg; 48 mg; 38 mg; 28 mg.
* * * * *