WO2013070191A1

WO2013070191A1 - Method and apparatus for coupling a fluid meter case to a pipeline interface

Info

Publication number: WO2013070191A1
Application number: PCT/US2011/059720
Authority: WO
Inventors: Clinton Ray Griffin
Original assignee: Micro Motion, Inc.
Priority date: 2011-11-08
Filing date: 2011-11-08
Publication date: 2013-05-16
Also published as: AR088620A1

Abstract

A sensor assembly (5) of a fluid meter (100) is provided. The sensor assembly (5) comprises a case (101) and one or more pipeline interfaces (103a, 103b). The sensor assembly (5) further comprises one or more transition rings (102a, 102b), with a transition ring (102a, 102b) of the one or more transition rings (102a, 102b) coupled to a pipeline interface (103a, 103b) of the one or more pipeline interfaces (103a, 103b) at a first end (302a) comprising a first cross-sectional wall thickness (t₁) and coupled to the case (101) at a second end (302b) comprising a second cross-sectional wall thickness (t₂) less than the first cross-sectional wall thickness (t₁).

Description

METHOD AND APPARATUS FOR COUPLING A FLUID METER

CASE TO A PIPELINE INTERFACE

TECHNICAL FIELD

The embodiments described below relate to, fluid meters, and more particularly, to a method and apparatus for coupling a fluid meter case to a pipeline interface, such as a manifold.

BACKGROUND OF THE INVENTION

Fluid meters, such as Coriolis flow meters, vibrating densitometers, piezoelectric flow meters, etc. typically include one or more tubes for containing a fluid. The fluid may be flowing such as in a Coriolis flow meter or stationary such as in a vibrating densitometer. The fluid may comprise a liquid, a gas, or a combination thereof. In some situations, the fluid may include suspended particulates. Typically, the fluid tubes are enclosed in a case in order to protect the tubes and associated electrical components as well as provide a more stable environment.

In many situations, a portion of the fluid tubes extend out of the case and are joined to a pipeline interface, such as a manifold. The fluid tubes are generally joined to the manifold by welding. The manifolds are then typically brazed to case ends in a vacuum brazing operation. Once the appropriate electrical sensors are attached to the fluid tubes, the case ends are then welded to the case. The completed sensor assembly can then be coupled to the pipeline carrying a process fluid.

Obtaining adequate and reliable connections between the various components is often a problem with prior art fluid meters. One reason is due to thermal expansion of the materials used for the various components of the fluid meter. As the components are being coupled to one another, high temperatures are often involved, which can result in significant changes in the components' dimensions. This is especially true when the various components comprise metals that are coupled by welding, brazing, soldering, etc., which can require an excessive amount of heat. While this may not create a problem if all of the components are formed from the same material or materials with similar coefficients of thermal expansion as the components will expand and contract in unison, this is not always feasible. In many situations, the fluid tubes are formed from a different material than the case and the case ends. For example, when the process fluid in the fluid meter comprises a highly corrosive fluid, the fluid tubes need to be formed from a material that is highly corrosion resistant, such as titanium, tantalum, or zirconium. Similarly, any other portion of the wetted path should also be formed from high corrosion resistant materials. For example, in a dual fluid tube meter, the manifold is included in the wetted fluid path. Therefore, the manifold would also need to be formed from a highly corrosion resistant material. Likewise, in a single tube meter, the flanges used to couple the meter to a pipeline are included in the wetted fluid path. While the case and case ends would ideally be formed from the same material as the fluid tubes and the manifold, such an approach is typically cost prohibitive as titanium, tantalum, and zirconium are expensive metals. Therefore, portions of the fluid meter that are not in contact with the fluid are generally made from less expensive materials, such as stainless steel.

Although the different materials used to form the fluid meter may not be a problem when the fluid meter is at or near a predetermined temperature, such as room temperature, the differences in their coefficients of thermal expansion can create serious manufacturing problems as various portions of the meter are subjected to extreme temperature variations. A similar problem can be experienced in situations where the fluid is at an extreme temperature compared to the surrounding environment resulting in the wetted fluid path being subjected to a much higher temperature. The embodiments described below overcome these and other problems and an advance in the art is achieved. The embodiments described below provide an improved fluid meter that can combine various components having differing coefficients of thermal expansion without the above-mentioned drawbacks. SUMMARY OF THE INVENTION

A transition ring for coupling two dissimilar metals of a sensor assembly of a fluid meter is provided according to an embodiment. The transition ring comprises a first end comprising a first cross-sectional wall thickness. According to an embodiment, the transition ring further comprises a second end comprising a second cross-sectional wall thickness, wherein the first cross-sectional wall thickness is greater than the second cross-sectional wall thickness. A sensor assembly of a fluid meter is provided according to an embodiment. The sensor assembly comprises a case and one or more pipeline interfaces. According to an embodiment, the sensor assembly further comprises one or more transition rings. A transition ring of the one or more transition rings can be coupled to a pipeline interface of the one or more pipeline interfaces at a first end comprising a first cross-sectional wall thickness. According to an embodiment, the transition ring can be further coupled to the case at a second end comprising a second cross-sectional wall thickness less than the first cross-sectional wall thickness.

A method for coupling a pipeline interface to a fluid meter case is provided according to an embodiment. The method comprises a step of coupling the pipeline interface to a first end of a transition ring, wherein the first end comprises a first cross- sectional wall thickness. According to an embodiment, the method further comprises a step of coupling a second end of the transition ring to the fluid meter case, wherein the second end comprises a second cross-sectional wall thickness, which is less than the first cross-sectional wall thickness.

ASPECTS

According to an aspect, a transition ring for coupling two dissimilar metals of a sensor assembly of a fluid meter comprises:

a first end comprising a first cross-sectional wall thickness; and

a second end comprising a second cross-sectional wall thickness, wherein the first cross-sectional wall thickness is greater than the second cross- sectional wall thickness.

Preferably, the transition ring further comprises a groove proximate the first end extending at least partially around an outer circumference.

Preferably, the first cross-sectional wall thickness transitions towards the second cross-sectional wall thickness proximate the groove.

Preferably, the first cross-sectional wall thickness is at least three times greater than the second cross-sectional wall thickness.

According to another aspect, a sensor assembly of a fluid meter comprises:

a case;

one or more pipeline interfaces; and one or more transition rings, with a transition ring of the one or more transition rings coupled to a pipeline interface of the one or more pipeline interfaces at a first end comprising a first cross-sectional wall thickness and coupled to the case at a second end comprising a second cross-sectional wall thickness less than the first cross-sectional wall thickness.

Preferably, the sensor assembly further comprises one or more fluid tubes coupled to the one or more pipeline interfaces.

Preferably, the one or more pipeline interfaces comprise manifolds with two or more fluid tube apertures.

Preferably, the case comprises a material having a first coefficient of thermal expansion, the one or more pipeline interfaces comprise a material having a second coefficient of thermal expansion, and the one or more transition rings comprise a material having a third coefficient of thermal expansion between the first and second coefficients of thermal expansion.

Preferably, the transition ring is coupled to the pipeline interface by brazing.

Preferably, the transition ring is coupled to the case by welding.

According to another aspect, a method for coupling a pipeline interface to a fluid meter case comprises steps of:

coupling the pipeline interface to a first end of a transition ring, wherein the first end comprises a first cross-sectional wall thickness; and

coupling a second end of the transition ring to the fluid meter case, wherein the second end comprises a second cross-sectional wall thickness, which is less than the first cross-sectional wall thickness.

Preferably, the step of coupling the pipeline interface to the first end is performed by brazing.

Preferably, the step of coupling the second end of the transition ring to the fluid meter case is performed by welding.

Preferably, the fluid meter case comprises a material having a first coefficient of thermal expansion, the pipeline interface comprises a material having a second coefficient of thermal expansion, and the transition ring comprises a material having a third coefficient of thermal expansion between the first and second coefficients of thermal expansion. Preferably, the pipeline interface comprises a manifold including two or more fluid tube apertures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a fluid meter according to an embodiment.

FIG. 2 shows a manifold according to an embodiment.

FIG. 3 shows a transition ring for coupling a case to a pipeline interface according to an embodiment.

FIG. 4 shows a cross-sectional view of an end of the fluid meter according to an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 - 4 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of a flow meter. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the flow meter. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

FIG. 1 shows a fluid meter 100 according to an embodiment. The fluid meter 100 comprises a sensor assembly 5 and a meter electronics 20. The sensor assembly 5 comprises a case 101, a first transition ring 102a, a second transition ring 102b, a first pipeline interface 103a, and a second pipeline interface 103b. Within the case 101, the fluid meter 100 can include conventional components such as one or more fluid tubes (See FIG. 4) and suitable sensor components such as a driver, and one or more pick-off components. These components are generally known in the art and therefore, a discussion of the prior art components is omitted from the description for the sake of brevity. The case 101 includes a feed- thru 104 for electrical leads 50 that connect the sensor components to the meter electronics 20. A path 26 can provide an input and an output means that allows one or more meter electronics 20 to interface with an operator. The meter electronics 20 may interface with an operator using wire leads or some type of wireless communication interface, for example. The meter electronics 20 can measure one or more characteristics of the fluid under test such as, for example, a phase difference, a frequency, a time delay (phase difference divided by frequency), a density, a mass flow rate, a volumetric flow rate, a totalized mass flow, a temperature, a meter verification, and other information as is generally known in the art.

These features are generally known in the fluid meter industry and do not comprise a portion of the claimed embodiments. Thus a discussion of the particular operation of fluid meters and the meter electronics is omitted for brevity of the description.

FIG. 2 shows a pipeline interface 103 according to an embodiment. The pipeline interface 103 may comprise the first or the second pipeline interface 103a, 103b as both interfaces are substantially the same. In the embodiment shown, the pipeline interface 103 includes a first face 203a and a second face 203b, generally opposite the first face 203a. According to an embodiment, the first face 203a can be configured to abut and form a fluid- tight seal with a pipeline (not shown). Therefore, generally, the pipeline interface 103 will include one or more holes (not shown) configured to receive mechanical fasteners, such as bolts to provide a secure coupling between the pipeline interface 103 and the pipeline. Alternatively, the pipeline interface 103 may be provided as shown and a clamp can be used to hold the sensor assembly 5 to the pipeline.

According to the embodiment shown, the pipeline interface 103 comprises a manifold that separates a single fluid stream into two or more fluid streams. Therefore, the pipeline interface 103 shown may be utilized in dual tube meters, for example. The pipeline interface 103 therefore includes first and second fluid tube apertures 204, 204'. The first and second fluid tube apertures 204, 204' can be sized and located to receive two fluid tubes (See FIG. 4). Therefore, the first and second fluid tube apertures 204, 204' can receive a single fluid stream from the connected pipeline and separate the fluid between the two fluid apertures 204, 204'. Although the present embodiment shows two fluid apertures 204, 204', in other embodiments, more than two fluid apertures may be provided to split the fluid into more than two fluid streams. Alternatively, the pipeline interface 103 may comprise a single fluid aperture, such as in a single tube meter.

FIG. 3 shows a transition ring 102 according to an embodiment. The transition ring 102 may comprise the first transition ring 102a shown in FIG. 1 or the second transition ring 102b shown in FIG. 1 as the transition rings are substantially the same. The transition ring 102 is configured to be coupled to the pipeline interface 103 at a first end 302a and to the case 101 at a second end 302b. Therefore, the transition ring 102 can couple two dissimilar metals of a fluid meter. In some embodiments, the transition ring 102 can include a circumferential groove 303 proximate the first end 302a. The circumferential groove may be provided to allow access to appropriate mechanical fasteners when the fluid meter 100 is coupled to the pipeline.

FIG. 4 shows a cross-sectional view of the first end of the sensor assembly 5 of the fluid meter 100 according to an embodiment. Although only one end of the sensor assembly 5 is shown and described in FIG. 4, it should be appreciated that the second end comprises substantially similar components. Furthermore, where the same component is shown at the second end, the associated "a" and "b" are dropped from the following discussion. For example, the first end comprises a pipeline interface 103a while the second end comprises a pipeline interface 103b. In the discussion that follows, a pipeline interface 103 is referred to as both pipeline interfaces 103a, 103b are substantially identical.

According to the embodiment shown in FIG. 4, the pipeline interface 103 can separate an incoming fluid into the two fluid tubes 404, 404'. Therefore, in the embodiment shown in FIG. 4, the pipeline interface 103 comprises a manifold as discussed above in the description accompanying FIG. 2.

According to an embodiment, the fluid tubes 404, 404' may be formed from a first material. The first material may comprise a metal that has a relatively high resistance to corrosion, such as titanium, zirconium, or tantalum, for example. These metals are currently used in the fluid meter industry and have received success with various fluids including highly corrosive fluid environments.

According to an embodiment, the pipeline interface 103 can be coupled to the fluid tubes 404, 404'. Generally, the pipeline interface 103 is coupled to the fluid tubes 404, 404' via welding. However, other coupling methods may be employed, such as brazing, soldering, adhesives, etc. According to the embodiment shown, the pipeline interface 103 comprises a portion of the wetted fluid path. Consequently, in some situations it may be important to form the pipeline interface 103 of a material also having a high resistance to corrosion. According to an embodiment, the pipeline interface 103 can be formed from a material substantially similar to the material used for the fluid tubes 404, 404'. Therefore, in some embodiments, the pipeline interface 103 may comprise a metal such as titanium, zirconium, or tantalum, for example.

Not only does the substantially similar material used for the pipeline interface 103 provide increased corrosion resistance to the process fluid, but also, the pipeline interface 103 will have a coefficient of thermal expansion that is substantially similar to the coefficient of thermal expansion of the fluid tubes 404, 404', thereby permitting higher coupling techniques, such as welding.

As is generally known, the coefficients of thermal expansion of zirconium is between approximately 5.5-5.9 mm/m/°C; the coefficient of thermal expansion of tantalum is between approximately 6.3-6.7 mm/m/°C; and the coefficient of thermal expansion of titanium is approximately 7.0-7.4 mm/m/°C. Those skilled in the art will generally understand that these values may vary based on the purity of the metal and should in no way limit the scope of the description and claims. The values are merely provided as an example. Those skilled in the art will readily recognize how close the coefficient of thermal expansion for the pipeline interface 103 needs to be with respect to the coefficient of thermal expansion for the fluid tubes 404, 404' based on the intended applications.

According to an embodiment, the pipeline interface 103 is also coupled to the transition ring 102 at a first end 302a of the transition ring 102. Typically, the transition ring 102 is coupled to the pipeline interface 103 via brazing. According to one embodiment, the transition ring 102 may be coupled to the pipeline interface 103 by vacuum brazing. Generally, vacuum brazing is carried out by applying a brazing material between the pipeline interface 103 and the transition ring 102. The fluid tubes 404, 404', the pipeline interface 103, and the transition ring 102 are then placed into a vacuum brazing furnace (not shown) that is at a temperature high enough to melt the brazing material, thereby brazing the pipeline interface 103 and the transition ring 102 to one another. Those skilled in the art will recognize that the welded joint between the pipeline interface 103 and the fluid tubes 404, 404' can typically withstand the brazing furnace temperature as the welded joints typically melt at much higher temperatures than experienced in the brazing furnace.

According to the embodiment shown, the transition ring 102 is further coupled to the meter case 101 at the second end 302b. Generally, the transition ring 102 will be coupled to the meter case 101 by a weld joint; however, other methods may be utilized. According to an embodiment, the meter case 101 may comprise a material that is different from the material used to form the pipeline interface 103 and the fluid tubes 404, 404'. For example, it is common in the industry to utilize 300-series stainless steel for the meter case 101. Therefore, according to an embodiment, the transition ring 102 can couple two dissimilar metals of the sensor assembly 5.

A problem with using 300-series stainless steel is that 300-series stainless steel has a coefficient of thermal expansion that ranges from approximately 14-19 mm/m/°C. As can be appreciated, this is much higher than the coefficients of thermal expansion of the materials utilized for the pipeline interface 103.

With the different coefficients of thermal expansion, prior art meters suffer from a high failure rate of the joints during manufacturing. As the transition ring was being welded to the meter case in prior art meters, the heat generated by the welding operation would cause a high failure rate of the brazed joint between the transition ring and the pipeline interface. The transition ring 102 of the present embodiment overcomes this problem.

According to an embodiment, the transition ring 102 can be formed from a material having a coefficient of thermal expansion that is between the coefficients of thermal expansion of the pipeline interface 103 and the case 101. For example, in one embodiment, the transition ring 102 is formed from 400-series stainless steel. 400- series stainless steel generally has a coefficient of thermal expansion that is between approximately 10-12 mm/m/°C. As can be appreciated, the coefficient of thermal expansion of 400-series stainless steel is between the coefficients of thermal expansion for the above-mentioned materials, where the pipeline interface has a coefficient of thermal expansion between approximately 5.5-7.4 mm/m/°C and the meter case 101 has a coefficient of thermal expansion of approximately 14-19 mm/m/°C. Therefore, by providing the transition ring 102 with a coefficient of thermal expansion that is between the coefficients for the pipeline interface 103 and the meter case 101, stress due to temperature fluctuations is reduced.

In addition to the reduction in the coefficient of thermal expansion compared to the meter case 101, the transition ring 102 is also shaped to reduce stress at the joints. According to the embodiment shown, the transition ring 102 comprises a first cross- sectional wall thickness ti at the first end 302a where the transition ring 102 is coupled to the pipeline interface 103. The transition ring 102 comprises a second cross-sectional wall thickness t₂ at the second end 302b where the transition ring 102 is coupled to the meter case 101. According to an embodiment, the first cross-sectional wall thickness ti is greater than the second cross-sectional wall thickness t₂. In some embodiments, the first cross-sectional wall thickness ti is approximately three times as thick as the second cross-sectional wall thickness t₂. However, other differences between the two thicknesses t_l5 t₂ may be suitable. As shown, the cross-sectional wall thickness transitions between the two thicknesses ti and t₂ near the area of the groove 303. However, the transition between the two thicknesses may occur at other locations along the length of the transition ring 102.

According to an embodiment, the varying thicknesses of the transition ring 102 from the first end 302a to the second end 302b can reduce the stress applied to the coupling joint between the pipeline interface 103 and the transition ring 102 while the transition ring 102 is being coupled to the meter case 101. As mentioned above, the transition ring 102 is often coupled to the meter case 101 by welding. The transition ring 102 cannot usually be coupled to the meter case 101 during the vacuum brazing operation because the electronic components are placed within the case 101 prior to coupling the transition ring 102 to the meter case 101 and cannot usually withstand the high temperature operation. Consequently, welding is typically performed. According to an embodiment, the improved shape of the transition ring 102 prevents excessive stress from being applied to the brazed joint between the pipeline interface 103 and the transition ring 102 in a number of ways. As shown, the second end 302b comprises a much thinner cross-sectional wall thickness t₂. The thinner cross-sectional wall thickness reduces heat transfer from the second end 302b proximate the weld joint towards the first end 302a. As is generally known, heat transfer can be characterized using Fourier's law, which provides: dq . dT

— K

dA dx (1)

Where:

q = rate of heat flow in direction normal to surface;

A = surface area;

T = temperature;

x = distance measured normal to surface; and

k = thermal conductivity.

Therefore, Fourier's law provides that as the surface area increases, the rate of heat flow will also increase. Using Fourier's law in the present context, for a given length of the transition ring 102, as the cross-sectional wall thickness of the transition ring 102 increases, a greater amount of heat is transferred from the case/transition ring interface to the pipeline interface/transition ring interface. Therefore, the reduced thickness reduces the heat being transferred. Excessive heat can result in premature failure of the brazed joint and thus, a lower amount of heat delivered to the brazed joint is desirable.

In addition to the reduced heat transfer provided by the second cross-sectional wall thickness t₂, the smaller cross-sectional wall thickness t₂ also increases flexibility of the second end 302b of the transition ring 102. The increased flexibility can reduce motion experienced at the first end 302a due to radial expansion of the components while being heated. For example, as the second end 302b of the transition ring 102 is heated during the welding process, the heated area attempts to expand radially. The increased flexibility allows the second end 302b to expand radially due to the heat from the welding operation while the first end 302a can remain in a substantially un-expanded state or at least expansion at the first end 302a is reduced. The reduction in expansion at the first end results in less stress being applied to the braze joint.

While a relatively thin cross-sectional wall thickness at the second end 302b is preferable, it is generally undesirable to provide the entire transition ring 102 with a cross-sectional wall thickness of t₂. Rather, it is generally desirable to increase the cross-sectional area available for the brazed joint between the pipeline interface 103 and the transition ring 102. The increased cross-sectional area allows for a greater braze area, resulting in an increased ability to handle stress. Therefore, a larger surface area at the first end 302a, corresponding to a thicker wall cross-section, can tolerate a higher level of stress before the braze joint fails.

Therefore, as can be appreciated, the embodiments described above improve the coupling of the pipeline interface 103 to the meter case 101 using the improved transition ring 102. The improved transition ring 102 not only reduces the heat transferred to the pipeline interface/transition ring joint, but also allows a portion of the transition ring to flex. The combination results in a reduced overall stress being applied to the coupling between the pipeline interface 103 and the transition ring 102. Although the above-mentioned embodiments discuss specific methods for creating the various couplings, i.e., brazing and welding, it should be appreciated that these methods are merely provided as examples and should in no way limit the scope of the description and claims. Rather, those skilled in the art will readily recognize alternative methods that may be utilized in specific applications.

The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventor to be within the scope of the present description. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the present description. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present description.

Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other fluid meters, and not just to the embodiments described above and shown in the accompanying figures. Accordingly, the scope of the embodiments described above should be determined from the following claims.

Claims

CLAIMS We claim:

1. A transition ring (102) for coupling two dissimilar metals of a sensor assembly (5) of a fluid meter (100), comprising:

a first end (302a) comprising a first cross-sectional wall thickness (t ; and a second end (302b) comprising a second cross-sectional wall thickness (t₂), wherein the first cross-sectional wall thickness ( ) is greater than the second cross-sectional wall thickness (t₂).

2. The transition ring (102) of claim 1, further comprising a groove (303) proximate the first end (302a) extending at least partially around an outer circumference.

3. The transition ring (102) of claim 2, wherein the first cross-sectional wall thickness ( ) transitions towards the second cross-sectional wall thickness (t₂) proximate the groove (303).

4. The transition ring (102) of claim 1, wherein the first cross-sectional wall thickness ( ) is at least three times greater than the second cross-sectional wall thickness (t₂).

5. A sensor assembly (5) of a fluid meter (100), comprising:

a case (101);

one or more pipeline interfaces (103a, 103b); and

one or more transition rings (102a, 102b), with a transition ring (102a, 102b) of the one or more transition rings (102a, 102b) coupled to a pipeline interface (103 a, 103b) of the one or more pipeline interfaces (103 a, 103b) at a first end (302a) comprising a first cross-sectional wall thickness ( ) and coupled to the case (101) at a second end (302b) comprising a second cross-sectional wall thickness (t₂) less than the first cross-sectional wall thickness (t ).

6. The sensor assembly (5) of claim 5, further comprising one or more fluid tubes (404, 404') coupled to the one or more pipeline interfaces (103a, 103b).

7. The sensor assembly (5) of claim 5, wherein the one or more pipeline interfaces (103a, 103b) comprise manifolds with two or more fluid tube apertures (204, 204').

8. The sensor assembly (5) of claim 5, wherein the case (101) comprises a material having a first coefficient of thermal expansion, the one or more pipeline interfaces (103a, 103b) comprise a material having a second coefficient of thermal expansion, and the one or more transition rings (102a, 102b) comprise a material having a third coefficient of thermal expansion between the first and second coefficients of thermal expansion.

9. The sensor assembly (5) of claim 5, wherein the transition ring (102a, 102b) is coupled to the pipeline interface (103a, 103b) by brazing.

10. The sensor assembly (5) of claim 5, wherein the transition ring (102a, 102b) is coupled to the case (101) by welding.

11. A method for coupling a pipeline interface to a fluid meter case, comprising steps of:

12. The method of claim 11, wherein the step of coupling the pipeline interface to the first end is performed by brazing.

13. The method of claim 11, wherein the step of coupling the second end of the transition ring to the fluid meter case is performed by welding.

14. The method of claim 11, wherein the fluid meter case comprises a material having a first coefficient of thermal expansion, the pipeline interface comprises a material having a second coefficient of thermal expansion, and the transition ring comprises a material having a third coefficient of thermal expansion between the first and second coefficients of thermal expansion.

15. The method of claim 11, wherein the pipeline interface comprises a manifold including two or more fluid tube apertures.