U.S. patent application number 15/987188 was filed with the patent office on 2018-11-29 for powder delivery device.
The applicant listed for this patent is Mallinckrodt Pharma IP Trading D.A.C.. Invention is credited to Paul Greenhalgh, Eliane Schutte.
Application Number | 20180339144 15/987188 |
Document ID | / |
Family ID | 43598921 |
Filed Date | 2018-11-29 |
United States Patent
Application |
20180339144 |
Kind Code |
A1 |
Greenhalgh; Paul ; et
al. |
November 29, 2018 |
POWDER DELIVERY DEVICE
Abstract
Provided is a device for the dispensing of powders of the type
in which a generated gas flow entrains the powder to be dispensed
and carries the powder from the device via a barrel. The barrel has
a bore including a main portion with a continuous internal surface,
and is characterized in that the length of the main portion is at
least fifteen times its maximum internal diameter; and/or the
internal bore of the main portion is tapered; and/or the barrel has
an outwardly flared outlet portion.
Inventors: |
Greenhalgh; Paul;
(Cambridge, GB) ; Schutte; Eliane; (Leiden,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mallinckrodt Pharma IP Trading D.A.C. |
Dublin |
|
IE |
|
|
Family ID: |
43598921 |
Appl. No.: |
15/987188 |
Filed: |
May 23, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13995267 |
Jun 18, 2013 |
10010705 |
|
|
PCT/GB2011/052586 |
Dec 23, 2011 |
|
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15987188 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2202/064 20130101;
A61M 11/06 20130101; A61M 35/003 20130101 |
International
Class: |
A61M 35/00 20060101
A61M035/00; A61M 11/06 20060101 A61M011/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2010 |
GB |
1021881.6 |
Claims
1. A device for the dispensing of a haemostatic composition in dry
powder form comprising: a barrel comprising: a bore including a
main portion with a continuous internal surface through which a
generated gas flow entrains the powder to be dispensed, and an
outwardly flared outlet portion having an internal diameter and an
external diameter, wherein: a length of the main portion is at
least fifteen times a maximum internal diameter of the bore; the
internal diameter and external diameter of the outlet portion
increases from an upstream end to a downstream end of the outlet
portion; the maximum internal diameter of the main portion is from
1 mm to 6 mm; and the device is charged with a quantity of the
haemostatic composition in dry powder form for delivery to internal
tissue exposed during surgical procedures or after traumatic
injury.
2. A device as claimed in claim 1, wherein the internal bore of the
main portion is tapered.
3. A device as claimed in claim 1, wherein the barrel is rigid.
4. A device as claimed in claim 3, wherein the length of the main
portion of the barrel is at least eighteen times or at least twenty
times the maximum internal diameter of the bore.
5. A device as claimed in claim 3, wherein the length of the main
portion is between about 30 mm and 100 mm.
6. A device as claimed in claim 1, wherein the barrel is
flexible.
7. A device as claimed in claim 6, wherein the main portion of the
barrel has a length of between 50 mm and 300 mm.
8. A device as claimed in claim 6, wherein the internal diameter of
the barrel is between 1 mm and 5 mm.
9. A device as claimed in claim 6, wherein the main portion of the
barrel comprises a plastic tube.
10. A device as claimed in claim 9, wherein the barrel incorporates
one or more malleable elongate members.
11. A device as claimed in claim 10, wherein the elongate malleable
members are wires or rods.
12. A device as claimed in claim 11, wherein the wires or rods are
embedded in the plastic material from which the barrel is
formed.
13. A device as claimed in claim 11, wherein the one or more
elongate malleable members are one or more copper or copper-coated
steel wires.
14. A device as claimed in claim 1, wherein the internal diameter
of the main portion decreases from an upstream end to a downstream
end of the main portion.
15. A device as claimed in claim 1, wherein the internal diameter
of the main portion increases from an upstream end to a downstream
end of the main portion.
16. A device as claimed in claim 1, wherein the internal diameter
of the main portion increases from an upstream end to a downstream
end of the main portion or decreases from the upstream end to the
downstream end of the main portion at a taper angle of 0.5.degree.
to 3.degree..
17. A device as claimed in claim 1, wherein the outlet portion has
a length of between 5 mm and 25 mm.
18. A device as claimed in claim 17, wherein the internal diameter
of the outlet portion increases from the upstream end to the
downstream end by a factor of two or more.
19. A device as claimed in claim 1, wherein the barrel is provided
with a mounting that enables an orientation relative to the main
portion of the device of which it forms part to be varied.
20. A device as claimed in claim 19, wherein the mounting is a
ball-and-socket connector.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/995,267 filed Jun. 18, 2013 which claims the priority of
PCT/GB2011/052586, filed Dec. 23, 2011 and GB application number
1021881.6, filed Dec. 23, 2010, each of which is hereby
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] This invention relates to improvements in a device for the
dispensing of powder. In particular, the invention relates to an
improvement in devices of the general type disclosed in
International Patent Application WO2010/070333 (which is hereby
incorporated by reference). Such devices are of particular utility
in surgical procedures or other medical applications, for the
topical delivery of powder to an internal or external surface of
the body.
BACKGROUND
[0003] In devices of the type disclosed in WO2010/070333, a flow of
gas entrains powder that is to be dispensed and carries that powder
out of the device via a barrel. The barrel serves to direct the
powder to the desired application site. In the devices illustrated
in WO2010/070333, the barrels are rather short and are of simple
construction.
BRIEF SUMMARY
[0004] It has now surprisingly been found that the performance of
devices of the type disclosed in WO2010/070333 may be substantially
improved by modifications to the design of the barrel. In
particular, elongation of the barrel and/or the incorporation of
certain structural features in the internal bore of the barrel lead
to improvements.
[0005] Thus, according to the invention there is provided a device
for the dispensing of powder, the device being of the type in which
a generated gas flow entrains the powder to be dispensed and
carries the powder from the device via a barrel, the barrel having
a bore including a main portion with a continuous internal surface,
characterized in that:
[0006] (a) the length of the main portion is at least fifteen times
its maximum internal diameter; and/or
[0007] (b) the internal bore of the main portion is tapered;
and/or
[0008] (c) the barrel has an outwardly flared outlet portion.
[0009] The device according to the invention is advantageous in
that the form of the barrel may lead to certain improvements in
performance. In particular, the form of the barrel may be chosen in
such a way that the shape of the plume of powder emitted from the
device is optimised for a particular application. Thus, the
distribution of powder on the intended site of application may be
made more uniform. In addition, the velocity of the powder plume
may be increased, and this may result in the form of the plume
being maintained over greater distances, so that the powder plume
remains intact when projected over larger distances than those
obtained with a conventional device, enabling the powder delivery
device to be held a greater distance from the desired delivery
site. This may be advantageous, for instance, in surgical
procedures where it may not be possible to hold the device close to
the intended site of application of the powder. In addition,
fall-off of powder from the plume, under the influence of gravity,
may be reduced, leading to reduced deposition of powder at
undesired locations. In addition, the outlet may be less prone to
clogging, improving performance and reducing the maintenance
required. Dispersion of the powder as it leaves the device may also
be improved. In general, the device according to the invention may
operate effectively over a wide range of gasflow pressures, e.g.,
from about 0.5 bar to about 7 bar, though for most applications
pressures in the range 0.5 bar to 2 bar are generally satisfactory,
e.g., from 0.5 bar to 1.5 bar.
[0010] In some preferred embodiments of the device, the length of
the main portion is at least fifteen times its maximum internal
diameter; and the internal bore of the main portion is tapered.
[0011] In other embodiments of the device, the barrel has an
outwardly flared outlet portion.
[0012] In some particularly preferred embodiments of the
device:
[0013] (a) the length of the main portion is at least fifteen times
its maximum internal diameter; and
[0014] (b) the internal bore of the main portion is tapered;
and
[0015] (c) the barrel has an outwardly flared outlet portion.
[0016] In embodiments in which the barrel is elongated, the barrel
may be rigid or it may be flexible.
[0017] In rigid embodiments, the length of the main portion of the
barrel is at least fifteen times, e.g., at least eighteen times or
at least twenty times, its maximum internal diameter, or more.
[0018] In rigid embodiments, the length of the main portion is
typically between about 30 mm and 100 mm, e.g., about 50 mm or
about 75 mm. The maximum internal diameter of the main portion is
typically from 1 mm to 6 mm, e.g., about 2 mm or about 3 mm.
[0019] In flexible embodiments of the barrel, the barrel is
generally longer than for rigid embodiments, the length of the main
portion of the barrel typically being between about 50 mm and about
300 mm, more commonly between about 50 mm and about 200 mm, and
typically between about 100 mm and 180 mm, e.g., about 150 mm. The
internal diameter of the barrel in such embodiments is most
commonly between about 1 mm and about 6 mm, typically between about
1.5 mm and about 4 mm, e.g., about 2 mm or about 3 mm.
[0020] In order for the barrel to be flexible, its main portion is
typically formed as a plastics tube, the plastics material being
such that the tube may be manually deformed to the required shape
without occlusion of the internal bore. The nature of the required
shape will generally be dictated by the circumstances of the
procedure in which the device is being used. Most commonly, a
single bend may be introduced into the barrel by the user of the
device, but in other situations it may be necessary to form the
barrel into a more complex shape, e.g., with a double bend (i.e. an
"S"-shape or the like). It has surprisingly been found that, even
when bent into shapes as extreme as are ever likely to be required
in practice (e.g., two 90.degree. bends), the pattern of powder
dispensed from the device can remain satisfactory in terms of the
geometry of the plume of powder emerging from the distal end of the
barrel and the pattern of deposition of the powder.
[0021] The nature of the plastics material from which the flexible
elongate barrel is formed may be such that the tube retains the
shape into which it is deformed, at least for as long as is
required during normal use. Preferably, however, the barrel
incorporates one or more malleable elongate members that can be
readily deformed, and which have the effect of retaining the barrel
in the desired configuration until it is once again manually
deformed to another configuration. Such members may take the form
of wires or rods of metal or other malleable material that are
incorporated into the barrel. Most commonly, such wires or rods are
disposed parallel to the longitudinal axis of the barrel. In some
embodiments, the main portion of the barrel is a tube having more
than one lumen, one lumen (normally the one having the greatest
cross-sectional area) constituting the bore of the barrel along
which powder is dispensed, and at least one lumen accommodating one
or more wires or rods. In other embodiments, one or more wires or
rods are embedded in the plastics material from which the barrel is
formed. There may be just one such wire or rod, or there may be
two, three, four or more such wires. Where there is more than one
wire or rod, those wires or rods are most commonly equiangularly
spaced around the main portion of the barrel.
[0022] Forms of material that are suitable for the malleable wires
or rods are copper wire and copper-coated steel wire. In one
currently preferred embodiment, a single such wire is embedded in
the wall of the tube that constitutes the main portion of the
barrel. In other embodiments, two, three or four such wires may be
used.
[0023] In other embodiments, another form of malleable material may
be used to enable the form of the barrel to be altered. For
instance, the main portion of the barrel may be provided, along the
whole or part of its length, with a sheath of material that holds
its shape when deformed, e.g., a foam material of the type known as
memory foam or visco-elastic foam.
[0024] In embodiments in which the internal bore of the main
portion is tapered, the internal diameter of the bore may decrease
from the upstream to the downstream end of the main portion, i.e.,
the internal bore of the main portion may converge. Alternatively,
the internal diameter of the bore may increase from the upstream to
the downstream end of the main portion, i.e., the internal bore of
the main portion may diverge. The taper angle may typically be in
the range 0.5.degree. to 3.degree., more commonly 0.5.degree. to
2.degree.
[0025] Embodiments in which the main portion of the barrel is
flexible typically have a main portion that is considerably longer
than is the case for rigid embodiments. Those flexible embodiments
are typically formed by extrusion and in such cases will therefore
have an internal bore of constant cross-section. Embodiments in
which the main portion of the barrel is rigid are more commonly
formed by injection moulding, in which case the internal bore of
the main portion of the barrel may have a uniform cross-section or
may, more preferably, be tapered.
[0026] In embodiments in which the barrel has an outwardly flared
outlet portion, the outlet portion typically has a length of
between 5 mm and 25 mm, more commonly between 5 mm and 10 mm. The
internal diameter of the outlet portion may increase from its
upstream to its downstream end by a factor of two or more. As will
be readily appreciated, where the outlet portion is "flared", that
term refers to the internal shape of the outlet, i.e., to a
widening of the outlet from its upstream to its downstream end.
That widening may or may not be reflected in the external shape of
the outlet.
[0027] Apart from the modifications to the barrel described above,
the device according to the invention may be as described in
WO2010/070333, in particular in relation to FIGS. 3 to 12 of that
document. Briefly summarised, such a device has a main body that
may comprise upper and lower housing components formed in plastics
material by injection moulding. The main body may have the general
form of an elongate cylinder that is adapted to be held in a user's
hand, the underside of the lower component being shaped to
facilitate such grip. A push button-type actuator may be mounted in
the top of the main body such that, when the device is held by the
user, the actuator can be depressed by the thumb of the hand that
holds the device. A flexible tube may extend from the rear end of
the device and may be adapted to be connected to a gas source,
e.g., a source of compressed air. A connector may be provided at
the distal end of the tube. A vial containing the powder that is to
be dispensed from the device may be coupled to the device, e.g.,
via an upstanding spigot that is received within the mouth of the
vial. The barrel may extend from the front end of the device.
[0028] The barrel may be provided with a mounting that enables its
orientation relative to the main body of the device of which it
forms part to be varied. For instance, the barrel may engage the
main body of the device in the manner of a ball-and-socket
connector, so that the orientation of the barrel may be adjusted,
e.g., manually by the operator.
[0029] In presently preferred embodiments, however, the barrel is
connected to the main body of the device in a fixed orientation.
The barrel may be connected to the main body by a threaded
connection, or by a suitable quick release connection such as a
bayonet fitting. Other forms of connection may alternatively be
used, e.g., a luer lock-type connection, or an interference fit or
the like.
[0030] The device according to the invention may be manufactured
using medical grade materials, most components being most
conveniently manufactured in plastics by techniques such as
injection moulding and extrusion. Where appropriate, components may
be manufactured in other materials, e.g., glass or metal.
[0031] The device according to the invention may be used to deliver
a wide variety of powders to a surface of the body. Such powders
include agents intended to have a therapeutic effect, either in
terms of a pharmacological effect on the body or as disinfectants
or the like useful in the prevention or treatment of infections.
One particular field in which the device of the invention is
useful, however, is for the delivery of haemostatic powder
compositions to internal tissues exposed during surgical procedures
or after traumatic injury. Such haemostatic compositions, which may
also be described as tissue sealants, may for instance comprise dry
powder mixtures of fibrinogen and thrombin. Such a mixture is
essentially inert when formulated in the dry state, but once
hydrated, e.g., upon application to a bleeding wound, the mixture
leads to the production of fibrin which cross-links to form a blood
clot.
[0032] Thus, according to a further aspect of the invention, there
is provided a method of delivering a haemostatic composition to an
internal tissue exposed during surgical procedures or after
traumatic injury, which method comprises providing a device as
described above, which device is charged with a quantity of a
haemostatic composition in dry powder form, and dispensing said
composition from said device onto said tissue.
BRIEF DESCRIPTION OF DRAWINGS
[0033] The invention will now be described in greater detail, by
way of illustration only, with reference to the accompanying
drawings, in which:
[0034] FIG. 1 is a perspective view of a first embodiment of a
powder delivery device according to the invention;
[0035] FIG. 2 is a side view of the device of FIG. 1;
[0036] FIG. 3 shows a barrel that forms part of the device of FIG.
1;
[0037] FIG. 4 is a cross-sectional view of the barrel of FIG.
3;
[0038] FIGS. 5(a) and (b) illustrate the range of vertical movement
of the barrel;
[0039] FIGS. 6(a) and 6(b) illustrate the range of lateral movement
of the barrel;
[0040] FIG. 7 is a perspective view of a second embodiment of a
powder delivery device according to the invention, showing the
barrel separated from the main body of the device;
[0041] FIG. 8 is a perspective view from behind of the barrel of
the device of
[0042] FIG. 7;
[0043] FIG. 9 is a cross-sectional view of the barrel of FIG.
8;
[0044] FIG. 10 is a perspective view of a third embodiment of a
powder delivery device according to the invention, comprising the
main body of the second embodiment with an alternative form of
barrel attached to it;
[0045] FIG. 11 is a perspective view of the barrel shown in FIG.
10; and
[0046] FIG. 12 is a cross-sectional view of the barrel of FIG.
11.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0047] Referring first to FIGS. 1 and 2, a first embodiment of a
powder delivery device in accordance with the invention is
generally designated 20. Save for the inventive modification
described in greater detail below, the device 20 is of similar form
to the device illustrated in FIGS. 3 to 12 of WO2010/070333.
Briefly summarised, the device 20 has a main body that comprises
upper and lower housing components 23a, 23b that are formed in
plastics material by injection moulding. The main body has the
general form of an elongate cylinder that is adapted to be held in
a user's hand, the underside of the lower component 23b being
shaped to facilitate such grip. A push button-type actuator 27 is
mounted in the top of the main body such that, when the device 20
is held by the user, the actuator 27 can be depressed by the thumb
of the hand that holds the device 20.
[0048] A flexible tube 25 extends from the rear end of the device
20 and is adapted to be connected to a gas source, e.g., a source
of compressed air (not shown). A suitable connector 26 is provided
at the distal end of the tube 25.
[0049] A glass vial 31 is coupled to the device 20 via an
upstanding spigot (not visible) that is received within the mouth
of the vial 31. A pair of clips 35 engages with a peripheral lip of
the vial 31, so as to hold it securely in place. In other
embodiments, the vial 31 may simply engage the spigot or similar
formation with an interference fit and/or the spigot or similar
formation may have a degree of resilience enabling a clip-type
fitting to the vial. To facilitate sealing engagement of the vial
31 with the device 20, the formation that receives the mouth of the
vial 31 may incorporate or be formed from a suitable elastomeric
material (e.g., a thermoplastic elastomer). A device 20 having such
a fitting may be produced using a two-shot molding process.
[0050] As for the device described in WO2010/070333, the front end
of the device 20 is provided with a tubular barrel 29, through
which powder is dispensed from the device 20. The barrel 29 in the
present invention, however, is rather different in form to that
described in the earlier patent application, as is discussed in
greater detail below.
[0051] The base of the spigot with which the vial 31 is engaged is
closed by a perforated plate, such that when the device is in the
operative orientation shown in FIGS. 1 and 2, powder contained
within the vial 31 rests upon the perforated plate. When the
actuator 27 is depressed, gas is caused to flow through the device
20, as described in WO2010/070333. The flow of gas has two,
related, effects. First, the gas flow drives a mechanical agitator
in the form of a ball that is held captive within a circular track;
rotation of the ball around the track induces vibrations in the
device 20, the effect of which is to dislodge powder from the vial
31, through the perforated plate that constitutes the base of the
spigot that is engaged by the vial 31. Secondly, a proportion of
the gas flow is directed at the underside of the perforated plate,
entrains the powder that is dislodged from the vial 31 and carries
it from the device 20 via the barrel 29.
[0052] Thus, to dispense powder from the device 20, the user holds
the device 20 in one hand, directs the barrel 29 at the intended
site of application of the powder, and depresses the actuator 27
with the thumb. This permits gas to flow through the device 20,
causing the ball to rotate rapidly around the track and inducing a
degree of mechanical vibration that is transmitted to the vial 31.
Most of the gasflow is vented from the device 20. However, a small
proportion of gas is directed at the underside of the perforated
plate. The mechanical agitation of the device 20 caused by rotation
of the ball within the track facilitates the release of powder from
the vial 31. The powder is entrained in the flow of air that
escapes from the device 20 via the barrel 29. The powder is blown
out of the device 1 and deposited on the site of application.
[0053] As noted above, the device 20 differs from that disclosed in
WO2010/070333 in the form of the barrel 29. The barrel 29 is shown
in FIGS. 3 and 4.
[0054] As can be seen in FIG. 3, the barrel 29 is elongate and of
circular cross-section, extending from a ball-type connector 291 at
one end to a flared outlet 292 at the other. The ball-type
connector 291 is captivated within an opening at the front of the
main body of the device 20, between the upper and lower housing
components 23a, 23b, in the manner of a ball-and-socket joint.
[0055] As can be seen from FIG. 4, the barrel 29 has an internal
bore having an entry portion 293 that is of constant diameter, a
main bore 294 that is of reduced diameter relative to the entry
portion 292, and an outlet portion 295 within the flared outlet
292. The diameter of the main bore 294 reduces along its
length.
[0056] The overall length of the barrel 29 is approximately 70 mm.
The entry portion 293 of the internal bore has a diameter of
approximately 5 mm and a length of approximately 8 mm. The diameter
of the main bore 294, which has a length of approximately 48 mm,
reduces from approximately 3.5 mm adjacent the entry portion 293 to
approximately 2 mm where the main bore 294 meets the outlet portion
295. The angle of convergence of the internal wall of the main bore
294 relative to its longitudinal axis is thus approximately
1.degree.
[0057] The entry portion 293 receives a tube (not visible in the
drawings) by which the gasflow and entrained powder are fed from
the main body of the device 20 to the barrel 29.
[0058] The narrowing of the main bore 294 may cause an increase in
velocity of the gasflow as it exits the device 20 and, together
with the flared form of the outlet portion 295, this may help to
maintain the shape of the powder plume emitted from the device 20,
resulting in good coverage of the application site with powder.
Fall off of powder from the emitted plume, under the influence of
gravity, may be reduced, minimising the amount of powder that is
dispensed onto sites other those to which the powder is intended to
be delivered. The flared form of the outlet portion 295 also leads
to a reduced likelihood of clogging.
[0059] In this embodiment, directional control over the emitted
powder is achieved by virtue of the fact that the ball-type
connector 291 permits the orientation of the barrel 290 relative to
the main body of the device 20 to be varied over a wide range, both
vertically (see FIGS. 5(a) and 5(b)) and laterally (FIGS. 6(a) and
6(b)).
[0060] Turning now to FIG. 7, a second embodiment of a powder
delivery device according to the invention is generally designated
30. The device 30 is broadly similar to the first embodiment 20
described above in that it comprises a main body 123 that receives
vial 131 of powder. In this embodiment, the vial 131 is received
within a ring 137 of thermoplastic elastomer that is molded onto
the upper component of the main body 123 in a two-shot molding
process.
[0061] Like the first embodiment 20, the device 30 comprises a
tubular outlet barrel 39. In the second embodiment 30, however, the
barrel 39 connects to the main body 123 by means of a bayonet
fitting and has a fixed orientation relative to the main body
123.
[0062] As can be seen in FIG. 8, the face of the barrel that abuts
the main body 123 is formed with a male bayonet spigot 391 with a
central recess that receives the open end of a tube 135 (see FIG.
7) by which the gasflow and entrained powder are fed from the main
body 123 of the device to the barrel 39. The barrel 39 is injection
moulded in rigid plastics material (eg ABS) and (referring to FIG.
9), like the barrel 29 of the first embodiment 20, is formed with
an internal bore 394 that diminishes along its length (in this case
from an internal diameter of approximately 2.9 mm to an internal
diameter of approximately 2 mm). The barrel 39 has a flared outlet
392.
[0063] As for the first embodiment 20, the narrowing of the main
bore 394 may cause an increase in velocity of the gasflow as it
exits the device 30 and, together with the flared form of the
outlet 392, this may help to maintain the shape of the powder plume
emitted from the device 30, resulting in good coverage of the
application site with powder. Fall off of powder from the emitted
plume, under the influence of gravity, may be reduced, minimising
the amount of powder that is dispensed onto sites other than to
which the powder is intended to be delivered. The flared form of
the outlet 392 also leads to a reduced likelihood of clogging.
[0064] Finally, FIG. 10 depicts a third embodiment of a powder
delivery device according to the invention, which is generally
designated 40. This embodiment differs from the second embodiment
30 solely in the form of the outlet barrel 49. Indeed, the outlet
barrel 39 of the second embodiment 30 and the outlet barrel 49 of
the third embodiment 40 are interchangeable.
[0065] The form of the barrel 49 is shown in greater detail in
FIGS. 11 and 12. The barrel 49 comprises three components: a
bayonet hub 491, a flexible plastics tube 492 and an outlet tip
493.
[0066] The bayonet hub 491 is injection moulded in rigid plastics
material (e.g., polyamide) and corresponds in overall shape to the
proximal end of the rigid barrel 39 of the second embodiment 30. It
has a central bore 495 that terminates in a socket within which one
end of the flexible tube 492 is received. That end of the tube 492
may be fixed to the hub 491 by adhesive, by ultrasonic welding or
by any other suitable means. The other end of the tube 492 is
received within a similar socket formed in the outlet tip 493
(which is also formed by injection moulding of a suitable material,
e.g., polyamide) and may be fixed by similar means. The distal
(downstream) part of the outlet tip 493 has a flared internal
bore.
[0067] The flexible tube 492 is formed by extrusion in
polyurethane, a copper-coated steel wire 494 being embedded in the
wall of the flexible tube 492 during manufacture. A user of the
device may therefore form the flexible tube 492 into a desired
configuration, the effect of the wire 494 being to retain the tube
492 in that configuration during use. The third embodiment 40 may
be particularly useful in surgical procedures in which it is
desired to deposit the powder onto surfaces that are hidden and at
which a straight barrel cannot be directed.
* * * * *