CN108144161B

CN108144161B - Outer cover for pen needle assembly

Info

Publication number: CN108144161B
Application number: CN201611110864.4A
Authority: CN
Inventors: 曾曦; 黄华盛; 胡炜; 王绯; 范婷婷
Original assignee: Becton Dickinson and Co
Current assignee: Enbeckta
Priority date: 2016-12-06
Filing date: 2016-12-06
Publication date: 2021-08-31
Anticipated expiration: 2036-12-06
Also published as: CN108144161A

Abstract

A needle hub assembly coupled to a pen needle delivery device includes an outer cover having a first well that receives a needle hub and an inner shield covering a cannula of the needle hub. The second well bore is separate from the first well bore and is sized to receive the inner shroud. In use, a pen delivery device is coupled to the connecting end of the needle hub to withdraw the needle hub and inner shield from said first well. The inner shield is inserted into the second well in which it is gripped so that it can be detached from the needle hub without the user handling the outer or inner shield. After use, the needle hub is inserted into the first well and the pen needle delivery device is separated from the needle hub. The needle hub is retained in the first well, wherein the outer cover containing the used needle hub and the inner shield may be discarded as a single unit.

Description

Outer cover for pen needle assembly

Technical Field

The present invention relates generally to an outer cover for a pen needle assembly. More particularly, the present invention relates generally to an outer cover having a first well for holding a needle-hub with an inner shield and for holding the needle-hub after use to reduce the risk of accidental needle sticks. The outer cover has a second well for receiving the inner shield to separate the inner shield from the needle hub without handling the inner shield.

Background

Insulin and other injectable drugs are commonly delivered with drug delivery pens, where a disposable pen needle hub is attached to the pen to facilitate access to the drug container and to allow fluid to be expelled from the container through the needle into the patient.

A wide variety of pen needle delivery devices are known in the art for dispensing substances to a patient. Delivery devices typically use a disposable needle hub having a cannula or needle extending from the patient end of the hub for insertion into the patient. The non-patient end of the seat is coupled to a pen delivery device for delivering a substance to a patient.

The needle hub assembly is typically packaged in a container that houses several loose needle hubs. A needle hub is selected from the packaging, attached to the pen needle delivery device for injection of the needle into the patient, and then removed for disposal. The needle-seat package comprises an outer cover enclosing the needle-seat and a removable seal that is peeled from the outer cover to open the cavity so that the needle-seat can be removed. The needle hub may have a threaded non-patient end that is threaded onto the delivery device. The delivery device with attached needle hub is then removed from the outer cover. The inner needle shield is attached to the needle hub to cover the cannula until the device is ready for use. The shield is removed to expose the cannula for use to deliver the substance to the patient. After use, the needle hub may be inserted back into the outer cover to enclose the exposed cannula. The pen delivery device is separated from the needle hub leaving the needle hub inside the outer cover.

The prior devices require the use of both hands to connect and remove the needle hub from the delivery device. During replacement of the outer cover, the cannula is exposed, increasing the risk of accidental needle sticks. Manual operation of holding the outer cover while positioning the used up needle hub and cannula into the cavity of the outer cover without being pricked by an accidental needle can be difficult.

Prior pen needle assemblies are disclosed in U.S. patent application publication No. 2006/0229562 to Marsh et al and U.S. patent application publication No. 2007/0149924 to r.

While prior devices have been adapted for the intended use, there is a continuing need in the industry for improved packaging for pen needle holder assemblies.

Disclosure of Invention

The present invention is directed to an outer cover forming a package for a pen needle holder assembly. In particular, the present invention is directed to a package or outer cover for a needle hub that can be used in a manner that reduces the risk of accidental needle sticks.

In one embodiment of the invention, an outer cover for a needle hub is provided to maintain the needle hub and cannula in sterile conditions until use. The outer cover has a recess or well (well) for receiving the inner shield covering the cannula so that the inner shield can be removed from the needle hub without the operator handling the inner shield.

In accordance with another aspect of the invention, the inner cover may be inserted into the well in the outer cover such that the inner cover may be retained by a friction or interference fit. The needle hub and cannula may then be pulled apart from the inner shield while the inner shield is maintained in the well without the user handling the inner shield.

According to another aspect of the invention, after use, the needle hub and the cannula may be inserted into a needle hub well in the outer cover, wherein the pen needle delivery device may be separated from the needle hub. The needle hub is retained in the needle hub well bore by a friction or interference fit to enclose the cannula, reducing the risk of accidental needle sticks. The outer cover with the retained needle-hub portion may be safely discarded.

The various features of the present invention are basically attained by providing a package for a pen needle assembly comprising an outer cover receiving a needle hub with an inner shield covering a cannula of the needle hub. The outer cover has a bottom surface configured and dimensioned for contacting a support surface of the assembly and for supporting the outer cover in an upright position, and a top surface. The top surface of the outer cover has a first open well sized to receive and store the needle seat and the inner shield until ready for use. The outer cover may retain the needle hub by a friction fit or by an interference fit. The top surface of the outer cover includes an inner shield well dimensioned for receiving the inner shield and for retaining the inner shield after separation of the needle seat portion.

In one embodiment, the inner shield well is dimensioned to receive the inner shield by a friction or interference fit such that with sufficient force to grip the inner shield by insertion of the inner shield into the well, upon attachment to the pen needle, the needle seat may be pulled outwardly to separate from the inner shield to expose the cannula for delivery of the substance to the patient. After use of the needle hub and cannula, the needle hub is inserted into the needle hub well bore, where it is gripped by a friction or interference fit, so that the pen needle may be separated from the needle hub without the operator handling the needle hub, thereby reducing the risk of accidental needle sticks.

The features of the present invention are also achieved by providing a pen needle assembly for a pen needle delivery device, wherein the pen needle assembly comprises an outer cover, an inner needle shield and a needle hub having a needle cannula. The needle hub includes a body with a non-patient end for coupling to a pen needle delivery device, wherein the needle hub has a cannula extending from the patient end. The inner shield is coupled to the needle hub to cover the cannula. The outer cover has a bottom surface sized and configured for contacting a support surface and for maintaining the outer cover in an upright position. The outer cover has a top surface with a first well forming a needle-seat well for receiving the needle-seat and the inner shield. The top surface has a second well forming an inner needle shield sized to receive the inner shield. The second well bore is smaller in size than the first well bore. The inner shield may be received in the second well by a friction or interference fit to grip the inner shield such that the inner shield may be removed from the needle hub to be exposed without the operator manually removing the inner shield. After use, the needle hub may be inserted back into the first well to grip the needle hub so that the pen needle may be separated from the needle hub, and the spent or used needle hub may be retained in the outer cover for disposal.

Objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

Drawings

The above benefits and other advantages of various embodiments of the present invention will become more apparent from the following detailed description of exemplary embodiments of the invention and the accompanying drawings, in which:

figure 1 is an exploded perspective view of a pen needle assembly showing a pen delivery device, a needle hub, an inner shield and a cover in one embodiment;

FIG. 1A is a perspective view of an outer cover for containing a needle hub assembly showing a removable seal enclosing a needle hub and a cavity for an inner shield;

FIG. 2 is a top view of an array of needle hub portions which may be separated before or after use;

FIG. 3 is a perspective view of the array of FIG. 2;

FIG. 4 is an end view of the array of FIG. 2;

figure 5 is a cross-sectional view of the pen needle mount array of figure 2;

figure 6 is a perspective view of a pen needle delivery device positioned for coupling with a needle hub;

figure 7 is a side view of a pen needle delivery device inserted into an outer cover;

figure 8 is a cross-sectional view of a pen needle delivery device coupled to a needle hub;

fig. 9 is a cross-sectional view of the needle hub removed from the outer cover;

FIG. 10 is a cross-sectional view showing the needle hub positioned above the well of the inner shield for receiving the needle hub;

FIG. 11 is a perspective view showing the needle hub positioned over the well for receiving the inner shield;

FIG. 12 is a cross-sectional view showing the inner shroud positioned in the wellbore;

FIG. 13 is a perspective view showing the needle hub portion separated from the inner shield;

FIG. 14 is a cross-sectional view showing a used needle hub inserted into a well bore;

FIG. 15 is a perspective view showing a used needle hub inserted into a well bore;

figure 16 is a perspective view showing the pen needle delivery device separated from the needle hub portion;

figure 17 is a cross-sectional view showing the pen needle delivery device separated from the used needle hub; and

figure 18 is a bottom view of the outer cover.

Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures.

Detailed Description

The present invention relates to a package for containing a pen needle assembly for use with a pen delivery device. The invention also relates to a package assembly for a needle-hub, wherein the needle-hub can be placed in a cover which forms a package after use to reduce the risk of accidental needle sticks.

By packaging the pen needle assembly, it is possible to facilitate and ease the assembly and removal of the needle base assembly onto and from the pen delivery device with reduced handling of the exposed needle cannula. The outer cover for the needle hub can be placed on a flat plane (such as a table) so that the pen delivery device can be attached to the needle hub with one hand, thereby reducing the risk of needle sticks by handling the needle hub with an exposed needle cannula.

As shown in fig. 1, the pen needle delivery device 10 typically includes a metering knob/button, an outer housing 12, and a cover. The metering knob/button allows the user to set the metering of the medicament to be injected. The outer sheath 12 is grasped by the user when injecting the medicament. The cap is used by the user to securely hold the pen injection device 10 in a shirt pocket, purse or other suitable location and to provide covering/protection from accidental needle injury.

In a standard pen needle delivery device, both the dosing mechanism and the delivery mechanism are located in the outer housing 12 and are not described in more detail herein as they are understood by those skilled in the art. The drug cartridge is typically attached to a standard pen injector housing via a known attachment mechanism. Distal movement of the plunger or stopper in the medicament cartridge causes the medicament to be pushed into the container housing. The medicament cartridge is sealed by a septum and is pierced by a septum-penetrating needle cannula located in the container or housing. The container housing is preferably screwed onto the medicament cartridge, although other attachment mechanisms can be used. The pen needle delivery device can be a standard pen delivery device known in the industry and is therefore not shown in detail.

As shown in fig. 1, the pen needle delivery device 10 is connected to a needle hub 16 having an internally threaded connecting non-patient end that screws onto a threaded end 18 of the delivery device 10. A needle cannula 20 extends from the patient end of the needle hub 16 for delivering a substance to a patient. The outer cover 22 can be provided to cover the needle cannula to protect the patient from accidental needle sticks before and after use. The inner shield 24 is disposed on a post extending from the end of the needle hub 16 to enclose the cannula. During use, the needle hub 16 is connected to the pen delivery device and the inner shield is removed. After use, the outer cover is placed back substantially over the needle hub to cover the needle cannula. The needle hub with the cover is then removed from the pen needle delivery device and discarded.

In the present invention, the pen needle delivery device is adapted to be connected to a needle hub housed in an outer cover 30 forming a packaging system for the needle hub 16. The outer cover 30 forms a package for the needle-seat 16 during transport and handling of the needle-seat. As shown in fig. 1A, the outer cover 30 can be a single unit for a single needle hub. In other embodiments, as shown in fig. 2-5, the outer cover 30 can be an array 32 of multiple outer covers 30, each outer cover 30 housing a single needle hub 16. The array 32 of outer covers 30 can be joined together by a separate frangible line 34, perforation line, or other mechanism that enables individual outer covers 30 to be separated before or after use. The outer cover 30 can be separated into subassemblies as desired.

Each outer cover 30 includes a top surface 36 and a bottom surface 38. The top surface 36 is defined by a substantially flat planar member 37. Formed in top surface 36 are a recess forming a first well 40 sized to receive and store needle seat 16 and a second well 42 for receiving inner shield 24 of the needle seat assembly. As shown, the diameter of the well 42 for the inner shield 24 is smaller than the size of the well 40 for the needle hub 16.

As shown in fig. 1A, a seal 44 forming a closure member is attached to top surface 36 to overlie first well 40 to enclose the needle mount assembly until ready for use. In the illustrated embodiment, the seal is a flexible seal attached by an adhesive, such as a pressure sensitive adhesive that can be easily removed by a user at the time of use. Seal 44 is preferably a seal that can be peeled away by a user from the open well 40 and ceiling to expose needle hub 16. In other embodiments, the seal may be other forms of suitable seals capable of closing the recess and maintaining the needle hub 16 in a clean and sterile condition until use. The array 32 also has a seal 44 that closes each well of the outer cover 30 containing the needle hub portion 16. For ease of illustration, the seal 44 is not shown in fig. 2 and 3. As shown, the top surface 36 has markings or recesses that indicate the location of the seal 44.

The array 32 and the bottom surface 38 of the outer cover 30 form a substantially flat bottom configured to rest on a substantially flat surface during use, such as a table top, so that the outer cover and array are stable and can be used in a free standing manner. The bottom surface 38 is sized such that the outer cover 30 and/or array 32 is supported in an upright position. The bottom surface 38 may have a textured surface or a coating of a suitable non-slip material or a coating that inhibits sliding movement of the outer cover when placed on a support surface. In one embodiment, the outer cover stabilizes the assembly so that the operator can use one hand to connect the needle base assembly to the needle delivery device to reduce the risk of accidental needle sticks.

As shown in FIG. 18, well 40 and well 42 are spaced apart from each other and have substantially the same depth to form a support surface. The connecting portion 46 extends directly between the well bore 40 and the well bore 42. The connecting portion 48 extends between the well bore 40 and the well bore 42 and has a substantially L-shape. Each of the connecting

portions

46 and 48 has a height corresponding to the well 40 and the well 42 to form a support surface, and the bottom surface is sized to be able to support the outer cover 30 in an upright posture. The connecting

portions

46 and 48 have bottom edges at the bottom surface 38 of the cover 30 to form a stable surface for the cover when placed on a support surface. The bottom edge of the connecting portion may also have a texture or non-slip material or coating.

The well 40 in the outer cover 30 is sized to receive and support the needle hub 16 and the inner shield 24 as a free standing assembly or package. As shown in fig. 5 and 9, the well 40 has a first portion 50 with a substantially annular or circular sidewall 53 forming a well for receiving the needle hub 16. In the illustrated embodiment, the well 16 has a substantially cylindrical sidewall 52, the sidewall 52 mating with a circular sidewall 53 of the first portion 50 of the well 40. In one embodiment, sidewall 53 of first portion 50 is shaped and dimensioned to engage an outer surface of sidewall 52 to retain needle hub 16 in well bore 40 during storage and after use. In one embodiment, as shown in FIG. 9, the sidewall 52 of the well 40 may be formed with longitudinally extending ribs 54 that are capable of gripping the outer surface of the needle hub 16. The ribs 54 can be oriented to engage recesses formed in the outer wall 52 of the needle hub 16 to resist rotation relative to the outer cover 30 in order to screw the delivery device 10 onto the needle hub 16. In other embodiments, sidewall 52 may have a tapered portion to engage the outer surface of needle hub 16. The engagement force between sidewall 52 and needle-hub 16 may be a friction fit to retain the needle-hub in well 40. In other embodiments, the engagement force may be generated by an interference fit.

As shown in fig. 9, the tapered portion 56 extends from the bottom end of the first portion 50 to a longitudinally extending portion 58. In the illustrated embodiment, the longitudinally extending portion 58 has an open bottom end 60 at the bottom surface 38. The longitudinally extending portion 58 is shaped and dimensioned to receive the inner shield 24 in an initial arrangement to maintain the cannula and needle hub in a clean and sterile condition. The longitudinally extending portion 58 may have a taper that converges toward the bottom surface 38. The longitudinally extending portion 58 receives the inner shield without capturing the inner shield so that the inner shield remains connected to the needle hub 16 when the needle hub 16 is removed.

The second well 42 is sized and shaped sufficiently to receive and engage the inner shield 24 in a manner in which the inner shield can be captured and retained in the well 42 to separate the inner shield from the pen needle delivery device 10. As shown in FIG. 10, the well 42 has a longitudinal dimension with an inner wall 62 and an open bottom end 64. In the illustrated embodiment, the inner wall 62 has a first substantially cylindrical portion 66 at the top end of the top surface 36 and a second tapered portion 68 that converges toward the bottom surface 38. The tapered portion 68 forms a gripping surface for engaging the outer surface of the inner shroud 24 when inserted into the well bore 42.

The outer cover 30 contains the needle hub 16 as a packaging component that can be stored until ready for use. When needle-hub portion 16 is ready for use, seal 44 is peeled away from outer cover 30 to expose well 40 and needle-hub portion 16. Fig. 2 and 3 show the seal removed from each individual outer cover 30, but typically only one seal is separated at a time when the needle hub portion is needed for injection of a substance into a patient.

As shown in fig. 6-8, during use, the pen needle delivery device 10 is positioned over the open well 40 and inserted into the well 40 to couple the delivery device to the needle hub 16. In one embodiment, needle hub 16 is retained in well bore 40 with sufficient force such that the delivery device can be coupled to the needle hub with limited movement between the needle hub and the outer cover. Generally, the coupling mechanism of the delivery device has a threaded end that engages the internal threads of a needle hub as known in the art. Well bore 40 engages the needle hub with sufficient force that the delivery device can be screwed onto the needle hub while needle hub 16 is held in well bore 40 with limited movement between needle hub 16 and outer cover 30.

After the delivery device is screwed onto the needle seat 16, the needle seat and attached inner shield 24 are removed from the well bore 40, as shown in fig. 9. The delivery device 10 is then positioned over the second well bore 42 with the inner shroud 24 aligned with the well bore 42, as shown in fig. 10 and 11. The inner shield 24 is then inserted into the second well 42 as shown in figure 12, wherein the side walls of the well 42 engage the outer surface of the inner shield with sufficient force that the inner shield 24 remains in the well 42 as the pen needle delivery device 10 is pulled away from the cover 30. In this way, the needle hub 16 can be connected to the delivery device 10 and the inner shield 24 can be detached from the post of the needle hub 16 without the user handling the cover or inner shield, and exposure of the cannula is minimal with minimal risk of accidental needle sticks. As shown in fig. 13, the delivery device with attached needle hub 16 is ready to inject and deliver a substance to a patient.

After the needle hub 16 has been used, the used needle hub needs to be discarded in a safe manner. As shown in fig. 14, the used needle hub 16 is inserted back into the well bore 40 while still attached to the delivery device 10, wherein the needle hub 16 is grasped with sufficient force to enable the delivery device 10 to be separated from the used needle hub 16. In this embodiment, the delivery device 10 can be unscrewed from the needle hub 16. Then, as shown in fig. 16 and 17, the delivery device 10 is separated from the needle-hub portion 16. As shown in fig. 17, the used needle hub 16 and inner shield 24 remain in the

respective wells

40 and 42 after use. The delivery device 10 may then be reused by connecting to a clean, unused needle hub 16. The outer cover 30, holding the used needle hub 16 and inner shield, may then be discarded into a safe position. The needle hub 16 is preferably held in a well of the outer cover for proper disposal. The outer cover 30 with the respective needle-seat portion 16 and inner shield 24 may be separated from the array 32 and discarded separately. Alternatively, each needle seat may be used and returned to the respective well and array, and discarded as a unit when all needle seats are used.

The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the scope of the invention. The description of the exemplary embodiments of the present invention is intended to be illustrative, and not to limit the scope of the invention. Various modifications, substitutions, and alternatives will be apparent to those skilled in the art and are intended to be within the scope of the invention.

Claims

1. A needle hub assembly for a pen needle delivery device, the needle hub assembly comprising:

an outer cover having a bottom surface configured and dimensioned for contacting a support surface and for maintaining the outer cover in an upright orientation and a top surface opposite the bottom surface, the top surface having a first open well having an interior dimension;

a needle hub having a cannula extending from an end of the needle hub;

an inner shield coupled to the needle hub and covering the cannula in sterile conditions, the needle hub being received in the first open well;

a seal attached to the top surface, the seal covering the first open well and enclosing the needle seat; and is

The top surface has a second open well smaller than the first open well, the second open well being sized and configured to receive the inner shield, wherein the seal does not cover the second open well, and the inner shield is retained by inserting the inner shield into the second open well, whereby the inner shield is separable from the needle hub.

2. The needle mount assembly of claim 1, wherein the seal is attached to the top surface by a pressure sensitive adhesive.

3. The needle hub assembly of claim 1, wherein said seal is a peelable label.

4. The needle hub assembly of claim 1, further comprising a plurality of said outer covers coupled together in an array, each said outer cover comprising a needle hub.

5. The needle hub assembly of claim 4, wherein the plurality of outer covers are separated from one another by a frangible line extending between adjacent outer covers.

6. The needle hub assembly of claim 1, wherein said first open well is sized to receive said needle hub and said inner shield, said first open well engaging an outer surface of said needle hub to enable said needle hub to be coupled to said pen needle delivery device and said needle hub and said inner shield being separable from said first open well after coupling to said pen needle delivery device, said second open well having an inner wall with a first cylindrical portion and a second tapered portion configured for gripping said inner shield and an open bottom end.

7. The needle mount assembly of claim 1, wherein said first open well has a cylindrical sidewall with a cylindrical outer surface and said second open well has a cylindrical sidewall with a cylindrical outer surface, said cylindrical outer surface of said cylindrical sidewall of said second open well being spaced a distance from said cylindrical sidewall of said first open well for stabilizing said outer cover.

8. The needle mount assembly of claim 7, wherein the cylindrical sidewall of the first open well has a length equal to a length of the second open well, and the outer cover has a connecting portion extending between the first open well and the second open well, the connecting portion having a length equal to the lengths of the first open well and the second open well to secure the outer cover to a support surface, and wherein the connecting portion has an L-shape.

9. The needle mount assembly of claim 1, wherein said first open well has an open bottom end and said second open well has an open bottom end.

10. A needle-hub array for use with a pen needle delivery device, the needle-hub array comprising:

a plurality of outer covers coupled together, each outer cover having a bottom surface and a top surface opposite the bottom surface, the bottom surface is sized and configured for contacting a support surface and for maintaining the outer cover in an upright orientation, the top surface has a first open well with a first size and a second open well with a second size, said second dimension being less than said first dimension, said first open well having a cylindrical sidewall with a cylindrical outer surface, said second open well having a cylindrical sidewall with a cylindrical outer surface, said cylindrical outer surface of said cylindrical sidewall of said second open well being spaced from said first open well, a connecting portion extending between said cylindrical sidewall of said first open well and said cylindrical sidewall of said second open well; and

a needle seat received in each first open well, the needle seat having a cannula extending from an end of the needle seat and an inner shield covering the cannula, the outer cover enclosing the needle seat and the inner shield, a closure member closing the first open well, the first open well in the top face sized to receive the needle seat and the inner shield, the second open well sized and configured to receive the inner shield, wherein the inner shield is retained by inserting the inner shield into the second open well.

11. The array of needle hub portions of claim 10, wherein each outer cover includes a closure member closing the first open well.

12. The array of needle hub assemblies of claim 10, wherein the closure member is a removable seal attached to the top surface to close the first open well.

13. The array of needle hub portions of claim 10, wherein the plurality of outer covers are separable from one another.

14. The needle hub array of claim 10, wherein the plurality of outer covers are separable by a frangible line extending between adjacent outer covers.

15. The needle hub array of claim 10, wherein the first open well has a first portion sized to receive and retain the needle hub by a friction fit and a second portion sized to receive the inner shield, the second open well having an inner wall with an open bottom end, a first inner cylindrical portion at the top end and an inner tapered portion at the bottom end for gripping the inner shield.

16. The array of needle hub portions of claim 15, wherein the second open well is sized to receive and retain the inner shield by a friction fit.

17. The array of needle hub portions of claim 15, wherein the first and second open wells have open bottom ends at the bottom surface of the outer cover.

18. The needle hub array of claim 10, wherein the connecting portion extending between the first and second open wells has a length equal to the length of the first and second open wells, and the connecting portion has a bottom edge at the bottom surface of the outer cover to stabilize the outer cover.

19. A method of coupling and decoupling a needle hub with respect to a pen needle delivery device for delivering a substance to a patient, said method comprising the steps of:

providing an outer cover having a first well receiving a needle seat having an inner shield covering a cannula, removing a seal attached to a top surface of the outer cover for enclosing the needle seat in the first well;

inserting a pen needle delivery device into the first well and coupled to the coupling end of the needle hub;

removing said pen needle delivery device and needle hub from said first well;

inserting the inner shield coupled to the needle seat portion into a second well in the top surface of the outer cover, wherein the second well is spaced apart from the first well, the inner shield is grasped by the second well, and the needle seat portion is separated from the inner shield for use in delivering a substance to a patient; and is

Positioning the formed used needle seat in the first well and disengaging the needle seat from the pen needle delivery device.

20. The method of claim 19, wherein the first well bore has a cylindrical sidewall with a cylindrical outer surface, the second well bore has a cylindrical sidewall with a cylindrical outer surface, the cylindrical outer surface of the cylindrical sidewall of the second well bore is spaced apart from the first well bore, and a connecting portion extends between the first well bore and the second well bore to stabilize the outer cover.