PERISTALTIC PUMP TUBING WITH OUTER SLEEVE TUBING

Abstract

A peristaltic pump system includes a peristaltic pump having a roller assembly and a roller assembly housing. The roller assembly is disposed within the housing. The peristaltic pump defines a tubing maximum diameter and is configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter. The system includes peristaltic pump tubing including mainline tubing and outer sleeve tubing. The outer sleeve tubing is co-axially disposed about the mainline tubing. The mainline tubing and the outer sleeve tubing extend into, through, and out of the peristaltic pump and are engaged with the roller assembly. The mainline tubing has a mainline wall thickness. The outer sleeve tubing has a sleeve wall thickness. The mainline wall thickness and the sleeve wall thickness together are approximately the same as the conventional tubing wall thickness. A method of using the pump system is provided.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Application No. 17/161,985, filed Jan. 29, 2021, which relates to and claims the benefit of U.S. Provisional Application No. 62/971,550, filed Feb. 7, 2020, and entitled “PERISTALTIC PUMP TUBING WITH OUTER SLEEVE TUBING,” the entire contents of which is expressly incorporated herein by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND

This invention relates to peristaltic pumps, and more particularly to safety and use improvements thereto.

A peristaltic pump system consists of two principal component parts, pump tubing and a peristaltic pump. These parts must be mutually compatible in order for the peristaltic pump to be functional. A peristaltic pump is a mechanical pump in which pressure is provided by the movement of a constriction along a segment of the pump tubing, as in biological peristalsis. The constriction or pumping action is usually provided by the movement of one or more pump rollers rotatably mounted on a fixture which in turn rotates on an axis. The movement of the pump rollers along a segment of the tubing within a pump raceway propels fluid through the tubing. There are several interrelated factors that determine the pumping rate including the dimensions and elastic quality of the tubing, as well as the rate of compression applied by the pump rollers. The pump tubing is placed into the pump raceway and traditionally fixed by means of clamps, flanges or fixtures. Synonyms for peristaltic pump are roller pump, tube pump, and hose pump, and can also described in terms of its function, such as medical infusion pump.

The rate of fluid flow produced by a peristaltic pump is a function of 1) the angular velocity of a pump roller assembly and 2) the volume of fluid contained within the tubing delimited by constrictions produced by two consecutive pump rollers. An increase the inside diameter of the pump tubing within the pump raceway will increase the volume of fluid pumped with each cyclic compression of the pump tubing.

A traditional tubing arrangement includes the pump tubing in the form of silicon tubing with an inlet end, a central pumping segment which interacts with the pump rollers, and an outlet end. PVC connectors are connected to each end of the pump tubing at the inlet end and the outlet end. The PVC connectors are used to connect separate segments of IV tubing. Zip ties are typically used to fasten the PVC connectors to the silicone tubing (as medical protocol provides that PVC and silicon materials cannot be glued together). As examples of a peristaltic pump used for tumescent infiltration is the Klein Pump (HK Surgical, Inc, U.S. Pat. Publication No. 2004/0213685, filed October 2004 to Klein) and the pump disclosed in U.S. Pat. Serial 8,118,572, filed Aug. 12, 2009 to Klein, the disclosures of which are expressly incorporated herein by reference.

The overall functional efficacy of a peristaltic pump system depends on a combination of both the pump’s roller assembly and the pump tubing. Pump tubing is at least as important as the pump roller assembly and roller housing in terms of overall performance and reliability.

It is contemplated that there is a need in the art for an improved peristaltic pump system in comparison to the prior art.

BRIEF SUMMARY

According to an aspect of the present invention, there is provided a peristaltic pump system that includes a peristaltic pump and elastomeric peristaltic pump tubing. The peristaltic pump has a roller assembly and a roller assembly housing. The roller assembly is disposed within the roller assembly housing. The peristaltic pump defines a tubing maximum diameter and is configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter. The elastomeric peristaltic pump tubing includes mainline tubing and outer sleeve tubing. The outer sleeve tubing is co-axially disposed about the mainline tubing. The mainline tubing and the outer sleeve tubing extend into, through, and out of the peristaltic pump and are engaged with the roller assembly. The mainline tubing has a mainline wall thickness. The outer sleeve tubing has a sleeve wall thickness. The mainline wall thickness and the sleeve wall thickness together are approximately the same as the conventional tubing wall thickness.

According to various embodiments, the mainline tubing may have an outer diameter that is less than an inner diameter of the outer sleeve tubing. The mainline wall thickness may be a constant thickness. The sleeve wall thickness may be a constant thickness. The outer sleeve tubing may have a length less than a length of the mainline tubing. The mainline tubing may be formed of a medical grade polyvinyl chloride (PVC) material or other conventional medical grade materials. The outer sleeve tubing may be formed of a silicon material.

According to another aspect of the present invention, there is provided a method of use of a peristaltic pump system. The method includes the step of providing a peristaltic pump having a roller assembly and a roller assembly housing. The roller assembly is disposed within the roller assembly housing. The peristaltic pump defines a tubing maximum diameter and is configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter. The method further includes the step of providing elastomeric peristaltic pump tubing including mainline tubing and outer sleeve tubing. The mainline tubing has a mainline wall thickness. The outer sleeve tubing having a sleeve wall thickness. The mainline wall thickness and the sleeve wall thickness are approximately the same as the conventional tubing wall thickness. The method further includes the step of positioning the outer sleeve tubing co-axially about the mainline tubing. The method further includes the step of feeding the mainline tubing and the outer sleeve tubing into, through, and out of the peristaltic pump with the mainline tubing and the outer sleeve tubing engaged with the roller assembly. The outer sleeve tubing may be directly engaged with the roller assembly. The method may further include sliding the outer sleeve tubing axially along the mainline tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:

FIG. 1 is a front perspective view of a peristaltic pump system with a peristaltic pump (with a roller assembly depicted in dashed lining) and pump tubing according to an aspect of the present invention;

FIG. 2 is a side view with section lines indicating a partial longitudinal cross-section view depicting a prior art pump tube assembly with prior art tubing;

FIG. 3 is a cross-sectional view of the prior art pump tubing as viewed along axis 3-3 of FIG. 2;

FIG. 4 is a side view with section lines indicating a partial longitudinal cross-section view depicting the pump tubing of FIG. 1;

FIG. 5 is a cross-sectional view of the of the pump tubing as viewed along axis 5-5 of FIG. 4;

FIG. 6 is a cross-sectional view of the prior art pump tubing of FIG. 3 as depicted in a compressed configuration; and

FIG. 7 is a cross-sectional view of the pump tubing of FIG. 5 as depicted in a compressed configuration.

DETAILED DESCRIPTION

Illustrative embodiments of an improved design for peristaltic pump and tubing are described below. The following explanation provides specific details for a thorough understanding of and enabling description for these embodiments. One skilled in the art will understand that the invention may be practiced without such details. In other instances, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “above,” “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. When the claims use the word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.

Referring now to FIG. 1 there is depicted a front perspective view of a peristaltic pump system 10. According to an aspect of the present invention, there is provided the peristaltic pump system 10 that includes a peristaltic pump 12 and elastomeric peristaltic pump tubing 14. For purposes of this application, the term “elastomeric” will include all materials having pliable internal resiliency, such as rubber and/or rubber-like polyvinyl chloride, silicone or other polymer materials. The peristaltic pump 12 has a roller assembly 16 (depicted in dashed lining) and a roller assembly housing 18. The roller assembly 16 is disposed within the roller assembly housing 18. The peristaltic pump 12 defines a tubing maximum diameter and is configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter.

The elastomeric peristaltic pump tubing 14 includes mainline tubing 20 and outer sleeve tubing 22. In FIG. 1, the mainline tubing 20 is depicted in dashed lining within the sleeve tubing 22, and the sleeve tubing 22 is depicted in dashed lining with the roller assembly housing 18. Referring now additionally to FIG. 4 there is depicted a side view with section lines indicating a partial longitudinal cross-section view depicting the peristaltic pump tubing 14 of FIG. 1. Further, FIG. 5 depicts is a cross-sectional view of the of the peristaltic pump tubing 14 as viewed along axis 5-5 of FIG. 4. The outer sleeve tubing 22 is co-axially disposed about the mainline tubing 20. The mainline tubing 20 and the outer sleeve tubing 22 extend into, through, and out of the peristaltic pump 12 and are engaged with the roller assembly 16. The mainline tubing 20 has a mainline wall thickness (denoted “t2”). The outer sleeve tubing 22 has a sleeve wall thickness (denoted “t1”). The mainline wall thickness t2 and the sleeve wall thickness t1 together are approximately the same as the conventional tubing wall thickness (denoted “T” in FIG. 3 as discussed below) (in other words t1 + t2 = T).

As mentioned above the peristaltic pump 12 defines a tubing maximum diameter and is configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter. In this regard, it is contemplated that the peristaltic pump 12 would include a raceway gap between the roller of the roller assembly 16 and a roller raceway of the roller assembly housing 18 wherein the peristaltic pump tubing 14 positioned to functionally engage the roller assembly 16. Depending upon the design of the peristaltic pump 12, the roller assembly housing 18 may itself physically limit the tube diameter in which tubing may be inserted into the it without deformation of the tubing. The limiting dimension with respect to tube interaction with positioning into or within the peristaltic pump 12 would define the tubing maximum diameter. Presumably, the manufacturer of the peristaltic pump 12 would provide a recommended maximum tubing diameter for which the product is rated. In such a case, this dimension would be considered the maximum tubing diameter.

As mentioned above, The mainline wall thickness t2 and the sleeve wall thickness t1 together are approximately the same as the conventional tubing wall thickness T. As used in this context herein approximately the same refers to being within a tolerance of +- 5%.

According to various embodiments, it is contemplated that the dimensions of the mainline tubing 20 and the outer sleeve tubing 22 may be of a variety of sizes as chosen from those of one of ordinary skill in the art. It is contemplated that the present invention recognizes that the peristaltic pump tubing 14 may utilize commonly used IV tubing which coming is several standardized dimensions for the mainline tubing 20.

As used herein the outer diameter of a tube is the diameter of the circle congruent with the outer surface of a circular tube. As used herein the inside diameter of a tube is the diameter of the lumen of a tube having a circular-cross-section. It is contemplated that the inside diameter of the mainline tubing 20 is an important factor in determining the volume of fluid that is pumped in one 360 degree cycle of the peristaltic pump 12. For any given rate of roller assembly rotation the fluid flow rate is maximized by using tubing having the largest tube inside diameter. Also, as used herein the wall thickness is the cross-sectional thickness of the wall of a section of peristaltic pump tubing 14.

Referring now to FIGS. 2, 3 and 6 there is depicted prior art tubing arrangement that is commonly used with peristaltic pumps. FIG. 2 is a side view with section lines indicating a partial longitudinal cross-section view depicting a prior art pump tube assembly that includes prior art tubing 26 that interacts with a roller assembly of a peristaltic pump. FIG. 3 is a cross-sectional view of the prior art pump tubing 26 as viewed along axis 3-3 of FIG. 2. FIG. 6 is a cross-sectional view of the prior art pump tubing 26 of FIG. 3 as depicted in a compressed configuration. Input tubing 38 is attached to the prior art tubing 26 with the use of an input connector 40. An input fastener 42, such as a zip tie, may be used to secure the prior art tubing 36 over the input connector 40. Output tubing 44 is attached to the prior art tubing 26 with the use of an output connector 46. An output fastener 48, such as a zip tie, may be used to secure the prior art tubing 36 over the output connector 46. In this regard, the input tubing 38 and the output tubing 44 may be common IV tubing. The prior art tubing 26 has a substantially larger inner and outer diameter of that of the input tubing 38 and the output tubing 44 for proper interaction with the peristaltic pump. However, use, step-up, and manufacture of this tubing arrangement is much more complex and therefore costly than the peristaltic pump tubing 14 of the present invention that only utilizes the mainline tubing 20 (which may be formed of IV tubing) and the outer sleeve 22.

In this regard, the present invention recognizes that for a given peristaltic pump design of the peristaltic pump 12 that defines a tubing maximum diameter and is configured for use with conventional tubing (a single tube) with a conventional tubing wall thickness, the peristaltic pump tubing 14 may be instead used in place of such conventional tubing as long as the mainline wall thickness t2 of the mainline tubing 20 and the sleeve wall thickness t1 of the outer sleeve tubing 22 together are approximately the same as the conventional tubing wall thickness. This allows the peristaltic pump 12 to move fluid within the mainline tubing 20 while allowing the roller assembly 16 to have a sufficient outer diameter of the peristaltic pump tubing (the outer diameter of the outer sleeve OD1) for proper engagement. Furthermore, the two-piece design (the mainline tubing 20 and the outer sleeve tubing 22) is much simpler than the seven-piece prior art design described above.

The mainline wall thickness t2 may be a constant thickness, and the sleeve wall thickness t2 may be a constant thickness. In this regard, the outer and inner diameters of both the mainline tubing 20 and the outer sleeve tubing 22 may be constant as well. Nonetheless, nonconstant dimensioning may be utilized. As noted above, commonly available IV tubing may be used for the mainline tubing 20 which would have a constant dimensioning along its entire length. Furthermore, where the mainline tubing 20 and the outer sleeve tubing 22 are both of constant dimensions in terms of outer and inside diameters and thickness, the mainline tubing 20 may be readied inserted into the outer sleeve tubing 22 and subsequently positioned and repositioned as desired along the length of the mainline tubing 20.

In the context of the functional positioning of the mainline tubing 20 in relation to the peristaltic pump 12, the mainline tubing 20 includes a mainline input segment 24, a mainline output segment 26, and a mainline engagement segment 28 disposed between the mainline input segment 24 and the mainline output segment 26. Similarly, in the context of the functional positioning of the outer sleeve tubing 22 in relation to the peristaltic pump 12, the outer sleeve tubing 22 includes a sleeve input segment 30, a sleeve output segment 32, and a sleeve engagement segment 34 disposed between the sleeve input segment 30 and the sleeve output segment 32.

It is understood that the mainline engagement segment 28 and the sleeve engagement segment 34 represent those portions of the peristaltic pump tubing 14 that is disposed within or otherwise engaged with the peristaltic pump 12. In this regard the mainline engagement segment 28 and the sleeve engagement segment 34 are disposed between a raceway gap between the roller of the roller assembly 16 and a roller raceway of the roller assembly housing 18 which are cyclically compressed by the rollers of the roller assembly 16. Referring additionally to FIG. 7, there is depicted a cross-sectional view of the peristaltic pump tubing 14 of FIG. 5 as depicted in a compressed configuration.

The mainline engagement segment 28 is responsible for the pumping efficiency of the peristaltic pump 12. The larger the internal diameter (ID2) of the mainline tubing 20 at the mainline engagement segment 28, the greater will be the volume of fluid ejected with each cyclic compression by the roller assembly 12. In this exemplary depiction, the roller assembly 16 is understood to rotate in a clock-wise direction for pumping fluid from the left to the right. The mainline input segment 24 and the sleeve input segment 30 are disposed upstream of the peristaltic pump 12, and the mainline output segment 26 and the sleeve output segment 32 are disposed downstream of the peristaltic pump 12.

With this configuration, in the view of FIG. 1 it is understood that fluid would enter the mainline tubing 20 to the left of the mainline input segment 24 as indicated by the dashed lined arrow from some unidentified fluid source or reservoir. The mainline input segment 24 is the vacuum segment of the peristaltic pump tubing 14. Fluid flows into the mainline inlet segment 24 from a reservoir source, entering into the peristaltic pump tubing 14 via the mainline input segment 24 end and is drawn distally by the negative pressure generated by the roller assembly 16. Fluid flows from the mainline engagement segment 28 into the mainline output segment 26 being pushed by the positive pressure generated by the roller assembly 16.

The outer sleeve tubing 22 may have a length less than a length of the mainline tubing 20. In practice, the outer sleeve tubing 22 may be sized in relation to the overall sizing of the peristaltic pump 12 so as to extend at least an inch or several inches on each side of the roller assembly housing 18. For example, the outer sleeve tubing 22 may have a length of 8 inches and the roller assembly housing 18 may have a width of 4 inches. Such excess on each side of the roller assembly housing 18 ensures that a distal end of the outer sleeve tubing 22 does not entirely enter the roller assembly housing 18 giving rise to entanglement and allow for margin for longitudinal movement of the overall peristaltic pump tubing 14 with respect to the roller assembly housing 18.

The mainline tubing 20 and the outer sleeve tubing 22 are each formed of an elastomeric material that is configured to elastically and resiliently deform within the range of compression by the roller assembly 16. The mainline tubing 20 and the outer sleeve tubing 22 are each formed of materials that may be selected from those which are well known to one of ordinary skill in the art. For example, the mainline tubing 20 may be formed of a polyvinyl chloride (PVC) material, and the outer sleeve tubing 22 may be formed of a silicon material.

It is contemplated that the peristaltic pump 12 may be chosen from any of those which are well known to one of ordinary skill in the art. An example of a peristaltic pump 12 used for tumescent infiltration is the Klein Pump (HK Surgical, Inc, U.S. Pat. Publication No. 2004/0213685, filed October 2004 to Klein) and the pump disclosed in U.S. Pat. Serial No. 8,118,572, filed Aug. 12, 2009 to Klein. In this regard, the peristaltic pump 12 depicted in FIG. 1 is exemplary in nature. However common to peristaltic pump designs would be the functional inclusion of a roller assembly 16 (which may have more or less rollers than as depicted), a roller assembly housing 18, and various hardware/software control systems.

The teachings provided herein can be applied to other systems, not necessarily the system described herein. The elements and acts of the various embodiments described above can be combined to provide further embodiments. All of the above patents and applications and other references, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the invention.

Particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention.

The above detailed description of the embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above or to the particular field of usage mentioned in this disclosure. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. Also, the teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments.

All of the above patents and applications and other references, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the invention.

Changes can be made to the invention in light of the above “Detailed Description.” While the above description details certain embodiments of the invention and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Therefore, implementation details may vary considerably while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated.

In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention under the claims.

While certain aspects of the invention are presented below in certain claim forms, the inventor contemplates the various aspects of the invention in any number of claim forms. Accordingly, the inventor reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the invention.

The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.

Claims

1. A peristaltic pump system comprising:

a peristaltic pump having a roller assembly and a roller assembly housing, the roller assembly being disposed within the roller assembly housing, the peristaltic pump defining a tubing maximum diameter of and configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter, the conventional tubing being singular tubing made of one homogeneous material; and

elastomeric peristaltic pump tubing including mainline tubing and outer sleeve tubing, the outer sleeve tubing being co-axially disposed about the mainline tubing, the mainline tubing and the outer sleeve tubing extending into, through, and out of the peristaltic pump and engaged with the roller assembly, the mainline tubing having a mainline wall thickness, the outer sleeve tubing having a sleeve wall thickness, the mainline wall thickness and the sleeve wall thickness together being substantially the same as the conventional tubing wall thickness, the outer sleeve tubing having a constant outer diameter, the mainline tubing having an outer diameter that is less than an inner diameter of the outer sleeve tubing.

2. (canceled)

3. The peristaltic pump system of claim 1 wherein the mainline wall thickness is a constant thickness.

4. The peristaltic pump system of claim 1 wherein the sleeve wall thickness is a constant thickness.

5. The peristaltic pump system of claim 1 wherein the outer sleeve tubing has a length less than a length of the mainline tubing.

6. The peristaltic pump system of claim 1 wherein the mainline tubing is formed of a polyvinyl chloride (PVC) material.

7. The peristaltic pump system of claim 1 wherein the outer sleeve tubing is formed of a silicon material.

8. A method of use of a peristaltic pump system, the method comprising:

a) providing a peristaltic pump having a roller assembly and a roller assembly housing, the roller assembly being disposed within the roller assembly housing, the peristaltic pump defining a tubing maximum diameter and configured for use with conventional tubing having a conventional tubing wall thickness less than half of the tubing maximum diameter, the conventional tubing being singular tubing made of one homogeneous material;

b) providing elastomeric peristaltic pump tubing including mainline tubing and outer sleeve tubing, the mainline tubing having a mainline wall thickness, the outer sleeve tubing having a sleeve wall thickness, the mainline wall thickness and the sleeve wall thickness together being substantially the same as the conventional tubing wall thickness, the outer sleeve tubing having a constant outer diameter, the mainline tubing having an outer diameter that is less than an inner diameter of the outer sleeve tubing;

c) positioning the outer sleeve tubing co-axially about the mainline tubing; and

d) feeding the mainline tubing and the outer sleeve tubing into, through, and out of the peristaltic pump with the mainline tubing and the outer sleeve tubing engaged with the roller assembly.

9. The method of claim 8 wherein the outer sleeve tubing is directly engaged with the roller assembly.

10. The method of claim 8 wherein step c) includes sliding the outer sleeve tubing axially along the mainline tubing.

11. A peristaltic pump tubing comprising:

a mainline tubing section and outer sleeve tubing section, the outer sleeve tubing section being co-axially disposed about the mainline tubing section, the mainline tubing section and the outer sleeve tubing section sized and configured to extend into, through, and out of the peristaltic pump and engage with a roller assembly of the peristaltic pump, the mainline tubing section having a mainline wall thickness, the outer sleeve tubing section having a sleeve wall thickness, the mainline wall thickness and the sleeve wall thickness together being substantially the same as a conventional tubing wall thickness of a conventional tubing, the outer sleeve tubing having a constant outer diameter, the conventional tubing being singular tubing made of one homogeneous material, the mainline tubing having an outer diameter that is less than an inner diameter of the outer sleeve tubing.