Device and method for coupling a coupling to a flow tube in an ultrasonic flow meter

Abstract

A flow sensor subassembly for sensing a flow rate of a fluid medicament, comprising: a flow tube having an inlet and an outlet; a first coupler secured to the flow tube inlet; a second coupler secured to the flow tube outlet; a first piezoelectric element secured to the first coupler; a second piezoelectric element secured to the second coupler to define a predetermined distance between the first piezoelectric element and the second piezoelectric element; and at least one absorber sleeve engaged with the first coupler, the flow tube, and the second coupler.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 62 / 964,309, filed January 22, 2020, entitled “Apparatus and Method to Join a Coupler and Flow Tube in an Ultrasonic Flow Meter,” the entire disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application generally relates to a flow sensor subassembly for sensing flow of a fluid medicament. BACKGROUND

[0004] Referring to FIGS. 1 and 2, a flow sensor system 1 utilizing an ultrasonic flow meter includes a flow tube subassembly 2 having two piezoelectric transducers 4 coupled to a fluid flow tube 6. The transducers 4 are attached to a first coupler 7 and a second coupler 8, respectively, to which the flow tube 6 is attached. When the transducers 4 are excited by an electrical pulse, ultrasonic waves are transmitted into the fluid and flow tube 6. The system analyzes the waves traveling in the fluid to determine a velocity that is proportional to the shift between the signals received from the upstream and downstream transducers. Waves or signals traveling in the flow tube material are undesirable and are considered signal noise. The flow tube subassembly 2 includes an absorber tube 9 that is sleeved over the flow tube 6 between the couplers 7, 8. The ultrasonic energy traveling through the flow tube 6 is reduced by the absorber tube 9. The system 1 of FIGS. 1 and 2 can be the flow sensor system of U.S. Patent No. 9,970,794, which is incorporated herein by reference in its entirety. SUMMARY

[0005] In one aspect or embodiment, a flow sensor subassembly for sensing flow of a fluid medicament includes a flow tube having an inlet and an outlet, a first coupler secured to the flow tube inlet, a second coupler secured to the flow tube outlet, a first piezoelectric element secured to the first coupler, a second piezoelectric element secured to the second coupler to define a predetermined distance between the first piezoelectric element and the second piezoelectric element, and at least one absorber sleeve engaged with the first coupler, the flow tube, and the second coupler.

[0006] The at least one absorber sleeve can include a first absorber sleeve engaged with the first coupler and the flow tube and a second absorber sleeve engaged with the second coupler and the flow tube, wherein the first absorber sleeve is spaced apart from the second absorber sleeve to define a gap. In the gap between the first absorber sleeve and the second absorber sleeve, the flow tube can be uncovered by any absorbing material. The first absorber sleeve and the second absorber sleeve can each cover at least 10% of the length of the flow tube between the first coupler and the second coupler. The first absorber sleeve and the second absorber sleeve can each cover 25% of the length of the flow tube between the first coupler and the second coupler. The at least one absorber sleeve can comprise a thermoplastic polyurethane, and the flow tube can comprise stainless steel.

[0007] The flow tube can be secured to the first coupler and the second coupler via the at least one absorber sleeve. The interface between the first coupler and the second coupler and the flow tube can be free of adhesive.

[0008] The at least one absorber sleeve can be press-fit to the first coupler and the second coupler and the flow tube. The at least one absorber sleeve can be adhered to the first coupler and the second coupler and the flow tube. The at least one absorber sleeve can be overmolded onto the first coupler and the second coupler and the flow tube.

[0009] In another aspect or embodiment, a flow sensor subassembly for sensing a flow of a fluid medicament, comprising: a flow tube having an inlet and an outlet; a first coupler secured to the inlet of the flow tube; a second coupler secured to the outlet of the flow tube; a first piezoelectric element secured to the first coupler; a second piezoelectric element secured to the second coupler to define a predetermined distance between the first piezoelectric element and the second piezoelectric element; and the at least one absorber sleeve, wherein the flow tube is secured to the first coupler and the second coupler via the at least one absorber sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0010] The above and other features and advantages of the present disclosure and the manner of realizing the same will become more apparent and the disclosure will be better understood by reference to the following description of various aspects of the present disclosure taken together with the accompanying drawings, wherein:

[0011] FIG. 1 is a perspective view of a conventional flow sensor system.

[0012] FIG. 2 is a cross-sectional view of a flow tube subassembly of the conventional flow sensor system of FIG. 1.

[0013] Figure 3 is a top view of a flow tube subassembly according to an aspect or embodiment of the present application.

[0014] Figure 3A is a top view of a flow tube subassembly according to an aspect or embodiment of the present application. Figure 3is an enlarged view of area A of the flow tube subassembly of

[0015] Figure 3B is an enlarged view of area B of the flow tube subassembly of Figure 3

[0016] Figure 4 is a plot of signal level versus time comparing the flow tube subassembly of Figure 3

[0017] Figure 5 is an enlarged view of signal level versus time comparing the flow tube subassembly of Figure 3

[0018] Throughout the drawings, corresponding reference numerals indicate corresponding parts. The examples set forth herein illustrate exemplary aspects of the present disclosure and should not be construed as limiting the scope of the present disclosure. DETAILED DESCRIPTION

[0019] The following description is provided so as to enable any person skilled in the art to make and use the described aspects of the disclosure. Various modifications, equivalents, variations, and alternatives, however, will remain apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives are intended to fall within the spirit and scope of the present disclosure.

[0020] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof shall relate to the application as it is oriented in the drawing figures. However, it is to be understood that the application can assume various alternative orientations and, accordingly, such terms are not to be taken as limitations of the present application. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the present application. Hence, specific dimensions and other physical characteristics related to the aspects disclosed herein are not to be considered as limiting. All numbers and ranges recited in this specification are meant to be read as "about" that value or range. By way of example, a value recited as "25%” is meant to be read as "about 25%". However, this is not to be construed as limiting in any way but rather as a convenience to the patentee. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the present application. Hence, specific dimensions and other physical characteristics relating to the aspects disclosed herein are not to be considered as limiting. All numbers and ranges recited in this specification are meant to be read as "about" that value or range. By way of example, a value recited as "25%” is meant to be read as "about 25%". However, this is not to be construed as limiting in any way but rather as a convenience to the patentee.

[0021] ​​​All ranges or ratios disclosed herein are meant to include both the starting value and the ending value, as well as any and all sub-ranges or sub-ratios therein. For example, a stated range or ratio of "1 to 10" should be considered to include any and all sub-ranges or sub-ratios of the minimum value 1 and the maximum value 10; that is, all sub-ranges or sub-ratios beginning with a minimum of 1 or more and ending with a maximum of 10 or less. The ranges and / or ratios disclosed herein are meant to represent averages of the stated ranges and / or ratios.

[0022] The terms "first", "second", and the like, do not denote any particular order or chronology, but rather different conditions, properties, or elements.

[0023] Referring to Figure 3 , Figure 3A and Figure 3B , a flow sensor subassembly 10 for sensing a flow of a fluid medicament includes a flow tube 12 having an inlet 14 and an outlet 16, a first coupler 18 secured to the inlet 14 of the flow tube 12, a second coupler 20 secured to the outlet 16 of the flow tube 12, a first piezoelectric element 22 secured to the first coupler 18, a second piezoelectric element 24 secured to the second coupler 20 to define a predetermined distance D between the first piezoelectric element 22 and the second piezoelectric element 24, and at least one absorber sleeve 26 engaged with the first coupler 18, the flow tube 12, and the second coupler 20. In contrast to providing an absorber sleeve 26 on only the flow tube 12 without contact or engagement with the first coupler 18 and the second coupler 20, providing at least one absorber sleeve 26 engaged with the first coupler 18, the flow tube 12, and the second coupler 20 reduces the amount of ultrasonic energy transmitted into the material of the flow tube 12 via the first coupler 18 and the second coupler 20, thereby reducing the amount of signal noise. The flow sensor subassembly 10 can be used in conjunction with the flow sensor system 1 of FIG. 1, although the flow sensor subassembly 10 can also be used with other suitable flow sensor systems.

[0024] As shown in Figure 3 , Figure 3A and Figure 3B , in one aspect or embodiment, the at least one absorber sleeve 26 includes a first absorber sleeve 28 engaged with the first coupler 18 and the flow tube 12, and a second absorber sleeve 30 engaged with the second coupler 20 and the flow tube 12. The first absorber sleeve 28 is spaced apart from the second absorber sleeve 30 to define a gap 32. In the gap 32 between the first absorber sleeve 28 and the second absorber sleeve 30, the flow tube 12 is not covered by any absorber material. The first absorber sleeve 28 is directly engaged with both the first coupler 18 and the flow tube 12. The second absorber sleeve 30 is directly engaged with both the second coupler 20 and the flow tube 12.

[0025] In another aspect or embodiment, rather than providing a first absorber sleeve 28 and a second absorber sleeve 30, the at least one absorber sleeve 26 comprises a single piece of material that engages the first coupler 18, extends along the flow tube 12, and engages the second coupler 20.

[0026] In one aspect or embodiment, the first absorber sleeve 28 and the second absorber sleeve 30 each cover at least 10% of the length of the flow tube 12 between the first coupler 18 and the second coupler 20. In one aspect or embodiment, the first absorber sleeve 28 and the second absorber sleeve 30 each cover 25% of the length of the flow tube 12 between the first coupler 18 and the second coupler 20. In one aspect or embodiment, the first absorber sleeve 28 and the second absorber sleeve 30 each have an outer diameter of 6.2 mm, an inner diameter of 1.38 mm on the flow tube 12, and an inner diameter of 2.91 mm on the first coupler 18 and the second coupler 20. In one aspect or embodiment, a 12 millimeter length of the flow tube 12 is in direct contact with each of the first absorber sleeve 28 and the second absorber sleeve 30.

[0027] In one aspect or embodiment, the at least one absorber sleeve 26 is manufactured from a thermoplastic polyurethane, and the flow tube 12 is manufactured from stainless steel. The thermoplastic polyurethane can be Lubrizol’s Estane® 2363-55DE. Other materials having suitable acoustic damping properties can also be used, such as polyoxymethylene (POM). 2363-55DE. Other materials having suitable acoustic damping properties can also be used, such as polyoxymethylene (POM).

[0028] Referring again to Figure 3 , Figure 3A and Figure 3B , the flow tube 12 is secured to the first coupler 18 and the second coupler 20 via the at least one absorber sleeve 26. More specifically, in one aspect or embodiment, there is no adhesive between the first coupler 18 and the second coupler 20 and the flow tube 12 such that the first coupler 18 and the second coupler 20 are unconstrained relative to the flow tube 12, thereby increasing the strength of the ultrasonic waves. The interface between the first coupler 18 and the second coupler 20 and the flow tube 12 is adhesive-free, wherein the at least one absorber sleeve secures the first coupler 18 and the second coupler 20 to the flow tube 12.

[0029] In one aspect or embodiment, the at least one absorber sleeve 26 is press fit to the first and second couplers 18, 20 and the flow tube 12. In one aspect or embodiment, the at least one absorber sleeve 26 is adhered to the first and second couplers 18, 20 and the flow tube 12. In one aspect or embodiment, the at least one absorber sleeve 26 is overmolded onto the first and second couplers 18, 20 and the flow tube 12. Various combinations of these and other securing techniques can be used to secure the at least one absorber sleeve 26 to the first and second couplers 18, 20 and the flow tube 12.

[0030] Referring to Figure 4 and Figure 5 , a plot of signal level over time is shown comparing the flow tube subassembly 10 of Figure 3 to a conventional flow tube subassembly. As shown in Figure 4 , with the flow tube subassembly 10 of Figure 3 , the energy signal level through the fluid is higher compared to a conventional flow tube subassembly. Further, as shown in Figure 5 , with the flow tube subassembly 10 of Figure 3 , the energy noise level through the flow tube 12 is lower compared to a conventional flow tube subassembly.

[0031] Thus, the flow tube subassembly 10 of the present application improves the signal to noise ratio by providing a higher fluid signal and a lower flow tube noise signal compared to a conventional flow tube subassembly. The flow tube subassembly 10 also eliminates the need for a separate assembly method between the couplers 18, 20 and the flow tube 12.

[0032] While this disclosure has been described as having exemplary designs, the present disclosure can be further modified within the spirit and scope of the disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. One or more features of one or more embodiments or aspects can be combined with one or more features of any other embodiment or aspect, within the scope of the disclosure. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which the disclosure pertains and fall within the limits of the appended claims.

Claims

1. A flow sensor sub-assembly for sensing the flow rate of a fluid drug, comprising: A flow tube with an inlet and an outlet; A first connector fixed to the inlet of the flow tube; A second connector fixed to the outlet of the flow tube; A first piezoelectric element fixed to the first connector; A second piezoelectric element is fixed to the second connector to define a predetermined distance between the first piezoelectric element and the second piezoelectric element; as well as At least one absorber sleeve engages with at least the first connector or the second connector, wherein the at least one absorber sleeve covers at least a portion of the outer peripheral surface of the flow tube between the first connector and the second connector.

2. The flow sensor subassembly of claim 1, wherein the at least one absorber sleeve comprises a first absorber sleeve engaged with the first connector and the flow tube and a second absorber sleeve engaged with the second connector and the flow tube, the first absorber sleeve being spaced apart from the second absorber sleeve to define a gap.

3. The flow sensor subassembly of claim 2, wherein the flow tube is not covered by any absorbent material in the gap between the first absorber sleeve and the second absorber sleeve.

4. The flow sensor subassembly of claim 2, wherein the first absorber sleeve and the second absorber sleeve each cover at least 10% of the length of the flow tube between the first connector and the second connector.

5. The flow sensor subassembly of claim 4, wherein the first absorber sleeve and the second absorber sleeve each cover 25% of the length of the flow tube between the first connector and the second connector.

6. The flow sensor subassembly according to any one of claims 1-5, wherein the at least one absorber sleeve comprises thermoplastic polyurethane, and the flow tube comprises stainless steel.

7. The flow sensor subassembly according to any one of claims 1-6, wherein the flow tube is fixed to the first connector and the second connector via the at least one absorber sleeve.

8. The flow sensor subassembly according to any one of claims 1-7, wherein, There is no adhesive at the interface between the first and second connectors and the flow tube.

9. The flow sensor subassembly according to any one of claims 1-8, wherein the at least one absorber sleeve is press-fitted to the first connector, the second connector, and the flow tube.

10. The flow sensor subassembly according to any one of claims 1-9, wherein the at least one absorber sleeve is adhered to the first connector, the second connector, and the flow tube.

11. The flow sensor subassembly according to any one of claims 1-9, wherein the at least one absorber sleeve is overmolded onto the first connector, the second connector, and the flow tube.

12. A flow sensor sub-assembly for sensing the flow rate of a fluid drug, comprising: A flow tube with an inlet and an outlet; A first connector fixed to the inlet of the flow tube; A second connector fixed to the outlet of the flow tube; A first piezoelectric element fixed to the first connector; A second piezoelectric element is fixed to the second connector to define a predetermined distance between the first piezoelectric element and the second piezoelectric element; and A plurality of absorber sleeves, wherein the plurality of absorber sleeves are fixed to at least one of the first connector and the second connector, wherein the plurality of absorber sleeves cover at least a portion of the outer peripheral surface of the flow tube between the first connector and the second connector.

13. The flow sensor subassembly of claim 12, wherein the plurality of absorber sleeves includes a first absorber sleeve engaging with the first connector and the flow tube and a second absorber sleeve engaging with the second connector and the flow tube, the first absorber sleeve being spaced apart from the second absorber sleeve to define a gap.

14. The flow sensor subassembly of claim 13, wherein the flow tube is not covered by any absorbent material in the gap between the first absorber sleeve and the second absorber sleeve.

15. The flow sensor subassembly of claim 13, wherein the first absorber sleeve and the second absorber sleeve each cover at least 10% of the length of the flow tube between the first connector and the second connector.

16. The flow sensor subassembly of claim 15, wherein the first absorber sleeve and the second absorber sleeve each cover 25% of the length of the flow tube between the first connector and the second connector.

17. The flow sensor subassembly according to any one of claims 12-16, wherein the plurality of absorber sleeves comprise thermoplastic polyurethane, and the flow tube comprises stainless steel.

18. The flow sensor subassembly according to any one of claims 12-17, wherein, There is no adhesive at the interface between the first and second connectors and the flow tube.

19. The flow sensor subassembly according to any one of claims 12-18, wherein the plurality of absorber sleeves are press-fitted to the first connector, the second connector, and the flow tube.

20. The flow sensor subassembly according to any one of claims 12-19, wherein the plurality of absorber sleeves are adhered to the first connector, the second connector, and the flow tube.

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