Coriolis mass flow sensor

Abstract

The device and method include a Coriolis flow meter comprising first and second manifolds made of a polymer material. Each manifold includes a tubular port extension extending outward from the surface of the manifold. A flow sensing tube made of the polymer material is attached at a first end to the first tubular port extension and at a second end to the second tubular port extension. An insulating structure is clamped around a portion of the first tubular port extension and positioned adjacent to the surface of the first manifold. The insulating structure is made of a second material different from the polymer material.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority of U.S. Application No. 18 / 313,900, filed on May 8, 2023. The disclosure of the prior application is considered a part of this application and is incorporated into the disclosure of this application by reference.

[0002] This application relates to the measurement of fluid mass flow rate.

Background Art

[0003] A Coriolis flowmeter can be used to measure the mass flow rate of a fluid flowing through a closed conduit based on the Coriolis principle. A liquid or gas flows through a tube that is vibrated by a small actuator. The vibration generates a Coriolis acceleration in the liquid or gas flowing through the tube. The Coriolis acceleration of the fluid flow generates a force acting on the tube, which can be measured as a phase shift of the vibration frequency of the tube. The phase shift of the frequency is related to the inertia of the flow tube, including the fluid flowing inside the tube. A calibrated flowmeter can determine the mass flow rate of the fluid flowing through the flowmeter based on the shift in the vibration frequency.

Summary of the Invention

[0004] This disclosure describes a device and method for measuring fluid mass flow rate.

[0005] In one embodiment, the Coriolis flow meter includes: a first manifold made of a polymer material and including a first tubular port extension extending outward from the surface of the first manifold; a second manifold made of the same polymer material and including a second tubular port extension extending outward from the surface of the second manifold; a flow sensing tube made of the same polymer material, the flow sensing tube being attached at a first end to the first tubular port extension and at a second end to the second tubular port extension; and an isolating structure being clamped around a portion of the first tubular port extension and positioned adjacent to the surface of the first manifold, the isolating structure being made of a second material different from the polymer material.

[0006] In one embodiment, a method for manufacturing a Coriolis flow meter includes: manufacturing a first manifold made of a polymer material and including a first tubular port extension extending outward from the surface of a first manifold; manufacturing a second manifold made of the same polymer material and including a second tubular port extension extending outward from the surface of a second manifold; manufacturing a flow sensing tube from the same polymer material; welding a first end of the flow sensing tube to the first tubular port extension and welding a second end of the flow sensing tube to the second tubular port extension; and clamping an insulating structure around a portion of the first tubular port extension, which is positioned adjacent to the surface of the first manifold, the insulating structure being made of a second material different from the polymer material.

[0007] In one embodiment, the method includes providing a first manifold made of a polymer material, including a first tubular port extension extending outward from the surface of the first manifold; providing a second manifold made of the same polymer material, including a second tubular port extension extending outward from the surface of the second manifold; providing a flow sensing tube made of the same polymer material; welding a first end of the flow sensing tube to the first tubular port extension; welding a second end of the flow sensing tube to the second tubular port extension; and clamping an insulating structure around a portion of the first tubular port extension, which is positioned adjacent to the surface of the first manifold, the insulating structure being made of a second material different from the polymer material.

[0008] Implementations of these embodiments may include one or more of the following features:

[0009] In some implementations, the insulating structure isolates the flow sensing tube from external vibrations of the Coriolis flow meter.

[0010] In some implementations, the insulating structure includes stainless steel.

[0011] In some implementations, the insulating structure is clamped around a portion of the first and second tubular port extensions and positioned adjacent to both the surface of the first and second manifolds.

[0012] In some implementations, the flow sensing tube is a U-shaped tube, a V-shaped tube, or an Ω-shaped tube.

[0013] In some implementations, these embodiments further include a second insulating structure, which is clamped around a portion of the second tubular port extension and positioned adjacent to the surface of the second manifold, wherein the flow sensing tube is a straight tube.

[0014] In some implementations, these embodiments further include a base, which is attached to an insulating structure, and a protective enclosure connected to the base that surrounds a first manifold, a second manifold, and a flow sensing tube.

[0015] In some implementations, the flow sensing tube is welded to the first tubular port extension and the second tubular port extension.

[0016] In some implementations, these embodiments further include a second flow-sensing tube made of the polymer material, wherein the first manifold includes a third tubular port extension extending outward from the surface of the first manifold, the second manifold includes a fourth tubular port extension extending outward from the surface of the second manifold, and the second flow-sensing tube is attached to the third tubular port extension at a first end and to the fourth tubular port extension at a second end.

[0017] In some implementations, the insulating structure is clamped around each portion of the first, second, third, and fourth tubular port extensions and positioned adjacent to both the surface of the first manifold and the surface of the second manifold.

[0018] In some implementations, the insulating structure includes a first outer shell, a second outer shell, and a central shell, with the first and second tubular port extensions clamped between the first outer shell and the central shell, and the third and fourth tubular port extensions clamped between the second outer shell and the central shell.

[0019] In some implementations, these embodiments further include temporarily inserting a pin during welding at a location inside the flow sensing tube and the first tubular port extension, where the location corresponds to a polymer joint, and the pin is in close contact with the polymer joint to prevent polymer from flowing from the polymer joint into the flow sensing tube.

[0020] In some implementations, welding further includes locally heating the welding surfaces of the first and second tubular port extensions within the welding temperature range of the polymer material, locally heating the first end and the second end of the flow sensing tube within the welding temperature range of the polymer material, and simultaneously joining the first end of the flow sensing tube to the first tubular port extension and the second end of the flow sensing tube to the second tubular port extension, wherein each end and each welding surface of the flow sensing tube is within the welding temperature range of the polymer material.

[0021] In some implementations, the flow sensing tube is a straight pipe.

[0022] In some implementations, these embodiments further include mounting an insulating structure on a base and connecting a protective enclosure to a base surrounding the first and second manifolds and flow sensing tubes.

[0023] Certain implementations of the subject matter described herein may be implemented to achieve one or more of the following advantages:

[0024] The implementation of the Coriolis flowmeter described herein reduces the potential for metal contamination in systems requiring high-purity flow (e.g., semiconductor manufacturing and biopharmaceutical processes). The manifold and flow sensing tubes do not contain low-melting-point fusion-metals, thereby reducing or eliminating the risk of contamination of the flow path(s) by metal atoms.

[0025] In some implementations, the Coriolis flowmeter has corrosion resistance. The Coriolis flowmeter can withstand corrosive chemicals and / or other harsh chemicals used in various industries.

[0026] In some implementations, the flow sensing tube can be formed of a thin wall that improves measurement sensitivity even at low flow rates. In some implementations, the flow sensing tube can be formed from a commercially available polymer tube that is formed without sharp corners or abrupt direction changes, thereby eliminating locations where there is a potential for deposition of slurry solids that can cause an increase in pressure drop in the flowmeter and can cause particle fouling.

[0027] In some implementations, a separate insulation structure can tolerate a larger size and flow rate of the flow sensing tube compared to a flowmeter designed for high flow rates that has an integral insulation structure made of a polymer material for the manifold and the flow sensing tube, reducing material costs.

[0028] Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

Brief Description of the Drawings

[0029] [Figure 1A] Shows an assembled view of a Coriolis flowmeter assembly. [[ID=U22]] [Figure 1B] Shows an exploded view of a Coriolis flowmeter assembly. [Figure 2A] Shows a plan view of the geometric shape of a flow sensing tube. [[ID=Z27]] [Figure 2B] Shows a plan view of the geometric shape of a flow sensing tube. [[ID=S30]] [Figure 2C] Shows a plan view of the geometric shape of a flow sensing tube. [Figure 2D] Shows a plan view of the geometric shape of a flow sensing tube. [Figure 2E] Shows a plan view of the geometric shape of a flow sensing tube. [Figure 3] This is an isometric view of a Coriolis flow meter equipped with a linear flow sensing tube and integrated isolation plates. [Figure 4A] This shows an isometric view of a Coriolis flow meter with a linear flow sensing tube and a separate insulating structure. [Figure 4B] A plan view of a Coriolis flow meter with a linear flow sensing tube and a separate insulating structure is shown. [Figure 5] A flowchart showing the method for manufacturing a Coriolis flow meter is provided. [Figure 6] This shows a pin inserted into the flow sensing tube during welding. [Modes for carrying out the invention]

[0030] Figures 1A and 1B show an exemplary Coriolis flowmeter assembly 100. Figure 1A shows an assembled diagram 102 of assembly 100. Figure 1B shows an exploded view 104 of assembly 100. The Coriolis flowmeter assembly 100 includes manifolds 110, 111, flow sensing tubes 112, 113, and an insulating structure 114. Assembly 100 may have one or more flow sensing tubes 112. The assembly 100 shown in Figures 1A and 1B includes two flow sensing tubes 112 and 113.

[0031] Manifolds 110 and 111 fluidically couple the Coriolis flowmeter assembly 100 to a larger system capable of measuring the mass flow rate of the fluid through which the Coriolis flowmeter flows. Manifolds 110 and 111 also include internal passages for separating or coupling fluids flowing into or out of flow sensing tubes 112 and 113. The flow sensing tubes 112 and 113 can be vibrated at predetermined frequencies. The vibration frequency is shifted as the fluid flows through the flow sensing tubes 112 and 113. The mass flow rate of the fluid flowing through the flow sensing tubes 112 and 113 can be determined based on the shift in vibration frequency. An insulating structure 114 can insulate the flow sensing tubes 112 and 113 from external vibrations of the Coriolis flowmeter assembly 100. The insulating structure 114 can establish boundary conditions for the flow sensing tubes 112 and 113. The boundary conditions may relate to the effect of the mass flow rate on the shift in vibration frequency.

[0032] Each manifold 110 or 111 includes a body 116, a tubular port extension 118 extending outward from the surface of the body 116, and an inlet / outlet 120. In some examples, each manifold 110 or 111 may include a hole 122 to facilitate attachment to a support structure (e.g., an insulating structure 114). The body 116 provides a structure through which the tubular port extension 118 is connected and through which a fluid (whose flow rate is measured) passes. In some implementations, the body 116 is manufactured from a polymer material. For example, the body 116 may be manufactured from a single piece of polymer material by CNC (computer numerical control) machining. In some implementations, the body 116 is manufactured from a polymer material by injection molding or other molding processes. For example, the manifold channel connecting the inlet / outlet 120 and the tubular port extension 118 inside the main body 116 may be molded in situ or drilled in a separate machining operation after the main body 116 has been molded. The inlet / outlet 120 may be located on the side 124 of the main body 116 adjacent to the tubular port extension 118, as shown in Figures 1A and 1B. In some implementations, the inlet / outlet 120 may be located on the side 126 of the main body 116 opposite to the tubular port extension 118.

[0033] In some embodiments, the body 116 and the tubular port extension 118 are manufactured together from a single piece of polymer material. For example, the body 116 and the tubular port extension 118 may be manufactured using CNC machining from a single piece of polymer material, or by molding a single piece of polymer material. The body 116 (and any elements of the manifold 110 manufactured together with the body) may be manufactured from any one of a number of polymer materials, including but not limited to commercially available polymer materials (e.g., PFA, poly(etheretherketone) (PEEK), poly(vinylidene fluoride) (PVDF), poly(tetrafluoroethylene) (PTFE), poly(fluorinated ethylene propylene) (FEP)) or custom polymers and polymer blends.

[0034] The tubular port extension 118 is connected to the main body 116 and ultimately to the flow sensing tubes 112 and 113. In operation, the tubular port extension 118 vibrates as a continuous extension of the flow sensing tubes 112 and 113. The flow sensing tubes 112 and 113 can be connected to the tubular port extension 118 by welding. For example, the welded surface of each tubular port extension 118 is connected to the open end of the corresponding flow sensing tube, thereby creating fluid communication between the flow sensing tubes 112 and 113 and the corresponding manifold fluid passages. The tubular port extension 118 may have the same nominal outer diameter and nominal inner diameter, as well as dimensional tolerances, as the flow sensing tubes 112 and 113. These tolerances facilitate the precise alignment and welding of the tubular port extension 118 to the flow sensing tubes 112 and 113, as described below. In some implementations, the tubular port extension 118 is formed integrally with the body 116 (either by machining or molding). For example, since the tubular port extension 118 may be formed together with the body 116, it is seamlessly coupled to the body as a single structure without any separate or independent mechanical connections between the tubular port extension 118 and the body 116. Welding may be used to add components (e.g., flow sensing tubes and / or tubular port extensions) in a manner that integrates them with the body 116, as described below.

[0035] The isolation structure 114 is clamped around a portion of the tubular port extension 118 adjacent to the surface of the manifold 110. In some implementations, the isolation structure 114 includes outer shells 130 and 132 and a central shell 134. The port extension corresponding to the flow sensing tube 112 is clamped between the outer shell 130 and the central shell 134. The port extension corresponding to the flow sensing tube 113 is clamped between the outer shell 132 and the central shell 134. The isolation structure 114 may be made of a different material from the manifold 110 and the flow sensing tubes 112 and 113. For example, the isolation structure 114 may be made from a metal such as stainless steel. The isolation structure 114 may also be made from a polymer material.

[0036] In some implementations, the Coriolis flow meter includes a single flow sensing tube. In these implementations, the insulating structure includes two outer shells 130, 132 without a central shell 134. The outer shells 130, 132 are clamped around the tubular port extensions of each manifold of the Coriolis flow meter.

[0037] The insulating structure 114 establishes boundary conditions for the vibration of the flow sensing tubes 112 and 113 by providing fixed nodes where vibrations are measured. The insulating structure 114 affects the dynamic frequency response characteristics of the flow meter. For example, when the Coriolis flow meter is in operation, the flow sensing tubes 112 and 113 are made to vibrate in opposite directions from each other at their natural frequencies in phase opposition (e.g., "anti-phase"), resulting in a motion similar to that of a tuning fork. In addition, the flow sensing tubes 112 and 113 can also vibrate together in unison (e.g., symmetrically "in-phase"). Depending on the rigidity of the connection between the flow sensing tubes 112 and 113 and the main body 116, as well as the material and dimensions of the flow sensing tubes 112 and 113, the natural frequency of in-phase vibration may be close to (if not identical to) the natural frequency of anti-phase vibration. The closer the two frequencies are, the greater the risk of instability in the flowmeter, as the vibration excitation energy is uncontrollably shared between the two (in-phase and out-of-phase) vibration modes. When a Coriolis flowmeter is operated at its natural frequency, the natural frequencies of all vibration modes can be sufficiently separated so as not to interfere with the sensor's operation.

[0038] The insulating structure 114 creates clearly defined vibration boundary conditions that separate the frequencies of in-phase and out-of-phase modes by allowing different parts of the flow sensing tubes 112 and 113 (having different masses and moments of inertia) to participate in in-phase and out-of-phase vibrations. The dimensions and thickness of the insulating structure 114 also affect the frequency response of the flow meter because the insulating structure 114 affects the rigidity of the flow sensing tubes 112 and 113 vibrating in the out-of-phase mode. The insulating structure 114 directly affects the frequency response characteristics of the sensor to enable satisfactory performance. In some implementations, a brace bar 140 may be used to further adjust the natural frequencies of the in-phase and out-of-phase vibration modes.

[0039] In some implementations, the vibration boundary conditions are further improved by filling the annular gap 135 formed between the insulating structure 114 and the flow sensing tubes 112 and 113 with a filler. The filler may include, for example, epoxy, adhesive, sealant, foam, or other suitable filler.

[0040] The insulating structure 114 also provides vibration isolation from an external source (e.g., a structure to which a Coriolis flow meter is mounted), enabling frequency separation between the modes of the flow sensing tubes 112 and 113, regardless of whether they are vibrating in opposite-phase or in-phase mode.

[0041] Plumbing connections configured at the inlet / outlet 120 of the manifold 110 allow fluid to flow through the internal manifold fluid passages in a hydrodynamically parallel manner through each flow sensing tube 112, 113. The open ends of the flow sensing tubes are each welded to the corresponding weld surfaces of the tubular port extensions 118. In some embodiments, the welding operations of each flow sensing tube to the corresponding tubular port extensions are performed simultaneously. This aspect of the manufacturing method is described in more detail below with reference to Figure 5.

[0042] The polymer joint 150 may be an adhesive-free joint between the tubular port extension 118 and the open end of the flow sensing tube 112. For example, since the various elements of the manifold 110 and the flow sensing tubes 112, 113 can all be manufactured or molded from the same polymer material, the polymer joint 150 joins elements manufactured from the same polymer material. Thus, the tubular port extension 118 and the open ends of the flow sensing tubes 112, 113 only need to be heated within a welding temperature range (determined according to the polymer material used) and brought into contact with each other to form the polymer joint 150. In some embodiments, it is beneficial to weld all the open ends of the flow sensing tubes to all the tubular port extensions 118 simultaneously. This may be beneficial because it is more likely to produce a flowmeter in which the moments of inertia in both flow sensing tubes 112, 113 are close enough to be balanced. If welding is performed individually, there is a higher probability that at least one dimensional tolerance of the weld will not be met. Welds that deviate from dimensional tolerances will result in different lengths for the flow sensing tubes 112 and 113 (which constitute the vibrating structure), potentially leading to a vibrating structure that lacks a balanced moment of inertia.

[0043] Non-uniformity in the moment of inertia of each flow sensing tube 112, 113 can result in a dynamically unbalanced structure that adversely affects the accuracy (and zero-flow offset stability) of the flow meter. For example, an unbalanced structure is more sensitive to fluctuations in fluid and ambient temperature and is more susceptible to external vibrations, thus reducing the accuracy, precision, and reliability of the device's measurements. Details of manufacturing methods for producing flow sensing tubes with balanced moments of inertia are described in more detail below.

[0044] Figures 1A and 1B also show tabs 160 used to facilitate the attachment of the motion response device 162 to the flow sensing tubes 112 and 113. The tabs 160 are attached by sliding onto the flow sensing tubes 112 and 113 or the tubular port extension 118, by clamping onto the flow sensing tubes 112 and 113 or the tubular port extension 118, or by other means. The tabs 160 may be manufactured from a polymer material, but do not necessarily have to be the same material used to manufacture the other elements of the manifold 110. For example, the material used to manufacture the tabs 160 may be different from the material used to manufacture the flow sensing tubes 112 and 113 and may have a smaller coefficient of thermal expansion than the material used to manufacture the flow sensing tubes 112 and 113. The advantage of this is that the tabs 160 are more likely to maintain contact with the flow sensing tubes 112 and 113 as the system temperature changes, thereby maintaining measurement accuracy.

[0045] Figures 2A–2E show plan views of various shapes 205–225 of flow sensing tubes 112, 113 that can be connected to manifolds 110, 111 (represented schematicly as rectangular blocks). Any of the illustrated exemplary tube shapes 205–225 may be selected to meet the requirements of a particular flow measurement application. In some cases, the flow sensing tubes are U-shaped (e.g., 215), V-shaped (e.g., 220), or Ω-shaped (e.g., 210). In some cases, the flow sensing tubes are linear (e.g., 225). One advantage of manufacturing manifolds 110, 111 according to this disclosure is that any of the various tube shapes can be integrated for use as flow sensing tubes without the need to design entirely new manifolds 110, 111.

[0046] In some implementations, such as those using linear flow sensing tubes, a second insulating structure is provided. The first insulating structure is clamped around a portion of the tubular port extension(s) of the first manifold and positioned adjacent to the surface of the first manifold. The second insulating structure is clamped around a portion of the tubular port extension(s) of the second manifold and positioned adjacent to the surface of the second manifold.

[0047] Figure 3 shows an isometric view 300 of an exemplary Coriolis flowmeter 302. The Coriolis flowmeter 302 includes two manifolds 304 made of polymer material, each manifold having an inlet / outlet 306 and two tubular port extensions 308. Fluid can flow through the Coriolis flowmeter 302 in either direction. For example, the flow of the fluid to be measured may be from one inlet / outlet 306 to the other inlet / outlet 306. An insulating plate 310 is integrated with the manifold 304 and is made of the same polymer material. The insulating plate 310 establishes boundary conditions for the frequency response of the flowmeter 302. The insulating plate 310 may be manufactured at the same time as the manifold body. The insulating plate 310 is located between the body of the manifold 304 and the openings of the tubular port extensions 308. Two linear flow sensing tubes 312 are welded to the tubular port extensions 308 of each manifold 304. The polymer joints 314 may be formed using a process similar to the welding process described in relation to Figure 5. The manifold 304 is mounted on a base 320. The base 320 may be made of metal, for example, stainless steel. The base 320 has a much larger mass than the polymer manifold 304 and flow sensing tubes 312. For example, the base 320 may have a mass at least 2 to 20 times that of the polymer elements (304-312). The larger mass of the base 320 can help insulate vibrations from fluctuations in the flow system mounted on the inlet / outlet 306 and from other vibrations outside the flow meter 302. A protective enclosure 322 may be mounted on the base 320 and enclose the manifold 304, flow sensing tubes 312, and insulating plate 310. In some implementations, the base may be made of plastic or polymer material (for example, in the case of a flow meter in a corrosive environment), and mass may be added inside the protective enclosure to help with vibration isolation. In some implementations, the protective enclosure 322 may be made of a gamma-ray permeable material, allowing the flow meter 302 to be sterilized using gamma irradiation.

[0048] Figures 4A and 4B show isometric and top views 400 and 402 of a Coriolis flowmeter 404 having a linear flow sensing tube 406. Two manifolds 408 are formed from a polymer material, each manifold 408 having an inlet / outlet 410 on one side of the manifold body 412 and a tubular port extension on the opposite side of the inlet / outlet 410. The flow sensing tube 406 is welded to the tubular port extension to form a polymer joint. Two insulating structures 414 are made from a metal such as stainless steel, or a polymer material. The insulating structures 414 are clamped around the tubular port extension and positioned adjacent to the surface of the manifold 408. The insulating structures 414 include outer shells 416, 418 and a central shell 419. The insulating structures 414 are mounted to a base 420. In this example, the manifold 408 is mounted to the base 420 by the insulating structures 414. The base 420 may be made of the same material as the insulating structure 414, or the base 420 may be made of a different material. The base 420 may have a greater mass than the polymer elements (406-412) of the flow meter 404. A protective enclosure 424 may be attached to the base 420 to protect the flow sensing element of the flow meter 404. The protective enclosure may be made of a gamma-ray permeable material, allowing the flow meter 404 to be sterilized using gamma irradiation.

[0049] Figure 5 is a flow diagram of an exemplary method 500 for manufacturing a Coriolis flowmeter. A first manifold 110 is manufactured (505). For example, the first manifold 110 may be manufactured from a single polymer material through CNC machining or molding (e.g., injection molding). As described above, the manufactured manifold 110 includes a body 116 and a tubular port extension 118. The polymer used may be any of various commercially available polymers (e.g., PFA, PEEK, PVDF, PTFE, FEP), or a custom polymer or polymer blend. The manifold flow path through the body 116 may be manufactured in a single step together with the manifold, or it may be drilled (or otherwise created) after the manufacture of the manifold body 116.

[0050] A second manifold 111 is manufactured (510). For example, the second manifold 111 may be manufactured from a single polymer material. A method similar to that described above with reference to step 505 may be used to manufacture the second manifold 111. The second manifold 111 also includes a body 116 and a tubular port extension 118.

[0051] Flow sensing tubes 112 and 113 are manufactured (515). Flow sensing tubes 112 and 113 may be manufactured using the same polymer material used to manufacture the first manifold 110 and the second manifold 111. In some cases, flow sensing tubes 112 and 113 are commercially available tubes formed into specific shapes (as shown in Figures 2A to 2E). Shaping involves heating the tubes to near (or slightly above) the glass transition temperature of the polymer, forming the tubes into the desired shape (e.g., using a plate or other mold with the desired shape), maintaining the temperature to allow any mechanical stress in the formed tubes to dissipate, and cooling the flow sensing tubes 112 and 113 in a controlled manner. This heating, performed during the shaping process, is also known as annealing, and its temperature and temperature profile vary depending on the polymer material used. In some implementations, the annealing process may be performed before welding the flow sensing tubes 112 and 113 to the manifolds 110 and 111. In other implementations, the annealing process may be performed after welding the flow sensing tubes 112 and 113 to the manifolds 110 and 111.

[0052] To meet the design requirements for specific flow measurement applications and to match the polymer material of manifolds 110, 111, the flow sensing tubes 112, 113 may be manufactured from commercially available (or custom-made) polymer tubing (including, but not limited to, PFA, PEEK, PVDF, PTFE, and FEP). The inner and outer diameters of the flow sensing tubes 112, 113 (and corresponding matching tubular port extensions) may be arbitrary values, but the dimensional tolerances of these diameters (and / or wall thicknesses) may be within a few tenths of a millimeter. These tolerances facilitate the precise alignment of the flow sensing tubes 112, 113 into the tubular port extensions during welding.

[0053] The open ends of the flow sensing tubes 112 and 113 are welded to the weld surfaces of the tubular port extension 118 (520). The first ends of the flow sensing tubes 112 and 113 are welded to the tubular port extension 118 of the first manifold 110, and the second ends of the flow sensing tubes 112 and 113 are welded to the tubular port extension 118 of the second manifold 111. The open ends of the tubular port extension 118 and the open ends of the flow sensing tubes 112 and 113 are heated to a welding temperature range that is a function of the selected polymer. This can be done, for example, by locally heating the surfaces to be welded using a resistance heating element (e.g., a ceramic or metallic heating element) inserted between the physically close weld surfaces of the tubular port extension 118 and the open ends of the flow sensing tubes 112 and 113. When the weld surfaces and open ends reach the desired temperature, the heating element is removed. The open ends and weld surfaces are brought into contact simultaneously. An advantage of simultaneous welding is that the lengths of the flow sensing tubes 112 and 113 become nearly identical, and as a result, when used in a flow meter, the flow sensing tubes 112 and 113 have the same (or nearly identical) moment of inertia. Similarly, simultaneous welding facilitates the proper positioning of the flow sensing tubes 112 and 113, and as a result, the dimensions of the flow sensing tubes 112 and 113 based on their position are within the design tolerances. Other dimensions, such as the inner and outer diameters, may also be within the design tolerances of the target dimensions. Another advantage of welding is that the polymer flows together from both sides of the weld, thereby seamlessly integrating the flow sensing tubes 112 and 113 with the tubular port extension 118 without a separate mechanical joint that could degrade or reduce the performance of the flow meter.

[0054] To facilitate simultaneous and precise welding, fixtures may be used to hold the flow sensing tubes 112 and 113. For example, the flow sensing tubes 112 and 113 may be placed in fixtures configured to precisely position their open ends relative to each other and to the weld surfaces of the tubular port extensions 118, so as to satisfy dimensional tolerances. The fixtures are also configured to translate the flow sensing tubes 112 and 113 in a precise and controlled manner. Examples of such fixtures include moving tables used in machine tools, which may have surfaces with known flatness (e.g., flatness within 0.0001 of an inch).

[0055] In some examples, one or more pins may be inserted through the manifold fluid passage of the main body 116 to a position inside the flow sensing tube 112 or 113 and the tubular port extension 118, corresponding to the polymer joint (shown as polymer joint 150 in Figures 1A and 1B). This example is shown in Figure 6, where pin 610 is located inside the tubular port extension 620 and the flow sensing tube 640, corresponding to the polymer joint 605. Pin 610 will be in close contact with the inner surfaces of the tubular port extension 620, the flow sensing tube 640, and the polymer joint 605. However, for clarity, some separation between pin 610 and these surfaces is shown in Figure 6. Pins 610, made from any non-contaminating material that is mechanically and chemically stable within the welding temperature range of the polymers used to manufacture the manifolds 110, 111 and the flow sensing tubes 112, 113, are used to prevent any extrusion or flow of polymer from the polymer joint 605 into the flow path. This maintains the unobstructed continuity of the flow path required for accurate measurement. The pins 610 are then removed after the polymer joint 605 has solidified.

[0056] After welding, the assembled manifolds 110 and 111 are cooled in a controlled manner to dissipate any mechanical stress introduced during any of the preceding steps. The cooling temperature and temperature-to-time profile are functions of the polymer used to manufacture the assembled flowmeter.

[0057] Another advantage of the annealing process is that it reduces the risk of excessive polymer flow and warping from excessive thermal gradients across tubular components during uncontrolled cooling processes or faster cooling rates. This helps maintain dimensional control of the tubular elements within several thousand of an inch. This is used to maintain substantially equal moments of inertia in each oscillating flow-sensing tube 112, 113.

[0058] The insulating structure 114 is clamped around a portion of the first tubular port extension 118 and positioned adjacent to the surface of the first manifold 110 (525). The insulating structure 114 can be mounted to a base, and a protective enclosure can be mounted to a base to surround the manifolds 110, 111, the flow sensing tubes 112, 113, and the insulating structure 114.

[0059] In some implementations, such as those shown in the embodiments in Figures 1A and 1B, the insulating structure 114 is clamped around a portion of the tubular port extension 118 of both manifolds 110 and 111, and is adjacent to the surfaces of both the first manifold 110 and the second manifold 111.

[0060] Numerous embodiments of these systems and methods have been described. Nevertheless, it will be understood that various modifications can be made without departing from the scope of this disclosure. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A first manifold, made of polymer material, including a first tubular port extension extending outward from the surface of the first manifold, A second manifold, made from the aforementioned polymer material, including a second tubular port extension extending outward from the surface of the second manifold, A flow sensing tube made from the polymer material, wherein the flow sensing tube is attached to the first tubular port extension at a first end and to the second tubular port extension at a second end, An insulating structure, which is clamped around a portion of the first tubular port extension and positioned adjacent to the surface of the first manifold, wherein the insulating structure is made of a second material different from the polymer material, A Coriolis flow meter, including one.

2. The Coriolis flow meter according to claim 1, wherein the insulating structure insulates the flow sensing tube from external vibrations of the Coriolis flow meter.

3. The Coriolis flow meter according to claim 1, wherein the insulating structure includes stainless steel.

4. The Coriolis flow meter according to claim 1, wherein the insulating structure is clamped around a portion of the first tubular port extension and the second tubular port extension, and is positioned adjacent to both the surface of the first manifold and the surface of the second manifold.

5. The Coriolis flow meter according to claim 4, wherein the flow sensing tube is a U-shaped tube, a V-shaped tube, or an Ω-shaped tube.

6. The present invention further includes a second insulating structure, which is clamped around a portion of the second tubular port extension and positioned adjacent to the surface of the second manifold, The Coriolis flow meter according to claim 1, wherein the flow sensing tube is a straight tube.

7. The Coriolis flow meter according to claim 6, further comprising a base to which the insulating structure is attached, and a protective enclosure connected to the base, surrounding the first manifold, the second manifold, and the flow sensing tube.

8. The Coriolis flow meter according to claim 1, wherein the flow sensing tube is welded to the first tubular port extension and the second tubular port extension.

9. The present invention further includes a second flow sensing tube made from the aforementioned polymer material, The first manifold includes a third tubular port extension extending outward from the surface of the first manifold, The second manifold includes a fourth tubular port extension extending outward from the surface of the second manifold, The Coriolis flow meter according to claim 1, wherein the second flow sensing tube is attached to the third tubular port extension at its first end and to the fourth tubular port extension at its second end.

10. The Coriolis flow meter according to claim 9, wherein the insulating structure is clamped around each of the respective portions of the first tubular port extension, the second tubular port extension, the third tubular port extension, and the fourth tubular port extension, and is positioned adjacent to both the surface of the first manifold and the surface of the second manifold.

11. The insulating structure includes a first outer shell, a second outer shell, and a central shell. The first and second tubular port extensions are clamped between the first outer shell and the central shell. The Coriolis flow meter according to claim 10, wherein the third and fourth tubular port extensions are clamped between the second outer shell and the central shell.

12. A method for manufacturing a Coriolis flowmeter, wherein the method is To manufacture a first manifold made of a polymer material, including a first tubular port extension that extends outward from the surface of the first manifold, To manufacture a second manifold made of the polymer material, including a second tubular port extension that extends outward from the surface of the second manifold, To manufacture a flow sensing tube from the aforementioned polymer material, The first end of the flow sensing tube is welded to the first tubular port extension, and the second end of the flow sensing tube is welded to the second tubular port extension, The clamping of an insulating structure, which is positioned adjacent to the surface of the first manifold around a portion of the first tubular port extension, wherein the insulating structure is made of a second material different from the polymer material, A method that includes this.

13. The method according to claim 12, further comprising temporarily inserting a pin into a location inside the flow sensing tube and the first tubular port extension during welding, wherein the location corresponds to a polymer joint and the pin is in close contact with the polymer joint to prevent polymer from flowing from the polymer joint into the flow sensing tube.

14. The aforementioned welding, The welding surfaces of the first and second tubular port extensions are locally heated within the welding temperature range of the polymer material, The first and second ends of the flow sensing tube are locally heated within the welding temperature range of the polymer material, The method according to claim 13, further comprising joining the first end of the flow sensing tube to the first tubular port extension and the second end of the flow sensing tube to the second tubular port extension simultaneously while each end of the flow sensing tube and each weld surface are within the welding temperature range of the polymer material.

15. The method according to claim 12, wherein the insulating structure includes stainless steel.

16. The method according to claim 12, wherein the flow sensing tube is a U-shaped tube, a V-shaped tube, or an Ω-shaped tube.

17. The method according to claim 12, wherein the flow sensing tube is a straight pipe.

18. The aforementioned insulating structure is attached to the base, The method according to claim 17, further comprising connecting a protective enclosure to the base surrounding the first and second manifolds and the flow sensing tube.

19. To provide a first manifold made of a polymer material, which includes a first tubular port extension extending outward from the surface of the first manifold, To provide a second manifold made of the polymer material, including a second tubular port extension extending outward from the surface of the second manifold, To provide a flow sensing tube made from the aforementioned polymer material, The first end of the flow sensing tube is welded to the first tubular port extension, and the second end of the flow sensing tube is welded to the second tubular port extension, A method comprising clamping an insulating structure positioned adjacent to the surface of the first manifold around a portion of the first tubular port extension, wherein the insulating structure is made of a second material different from the polymer material.

20. The method according to claim 19, further comprising temporarily inserting a pin into a location inside the flow sensing tube and the first tubular port extension during welding, the location corresponding to a polymer joint, and the pin being in close contact with the polymer joint to prevent polymer from flowing from the polymer joint into the flow sensing tube.

21. The method according to claim 19, wherein the flow sensing tube is a straight pipe.

22. The aforementioned insulating structure is installed on a base, Connecting a protective enclosure to the base surrounding the first manifold, the second manifold, and the flow sensing tube, The method according to claim 21, further comprising:

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