Patent Description:
Accurate measurements of the properties of fluids delivered through flow systems is important for a variety of applications, such as in bioprocessing systems and oil and gas pipelines. One technique for measuring the properties of fluids is by using the flow rate. This permits measurements to be performed during fluid delivery, which is advantageous for reducing associated operating costs. That is, active flow systems may be operational during measurement. Flow rates may be measured either as volumetric flow rates or mass flow rates. Volumetric flow rates are accurate if the density of the fluid is constant; however, this is not always the case as the density may change significantly with temperature, pressure, or composition. As such, mass flow rates are typically more reliable for measuring fluid flow. One method for measuring mass flow rates is through a Coriolis flow sensor (e.g., a flow meter). In general, a Coriolis flow sensor measures mass flow rates via the Coriolis force that results from the fluid as it moves through an oscillating tube. Various known Coriolis flow sensor devices are described, for example, in <CIT>, <CIT> (which relates to a flow meter in which a hose is detachably fixed therein), <CIT> and <CIT>.

According the invention, it is disclosed a Coriolis flow sensor system comprising: a fluid flow assembly, a flow tube configured to provide a flow path through the flow tube; a mechanical drive assembly configured to drive an oscillation of the flow tube while fluid is flowing, wherein the mechanical drive assembly comprises an oscillation surface; and an interface fixedly coupled to the oscillation surface of the mechanical drive assembly and configured to receive the flow tube such that at least a portion of the interface is in direct contact with the flow tube and such that the interface transfers oscillation forces of the oscillation surface to the flow tube; wherein the oscillation surface of the mechanical drive assembly comprises a plurality of anchor points for connecting the interface thereto, and the interface is coupled to the fluid flow assembly with one or more rib structures, or with one or more wall features, disposed along the interface in a direction of the flow path. Preferential embodiments are disclosed in dependent claims <NUM>-<NUM>. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a summary of possible embodiments. Indeed, the disclosure may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

Various aspects and embodiments of the present invention are defined by the appended claims.

Various features, aspects, and advantages of the present invention will also become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:.

Coriolis flow sensors are useful in numerous applications that involve fluid delivery, such as bioprocessing systems. In general, a Coriolis flow sensor operates by measuring a phase shift of one or more oscillating flow tubes that results from a Coriolis force. It is beneficial to provide a Coriolis flow sensor design that increases the effect of the Coriolis force, which in turn results in an increased mass flow sensitivity and sensing amplitude (high signal to noise ratio: SNR). Certain Coriolis flow sensors are often used in conjunction with a continuous tubing that is uniform along its length.

Certain approaches to implementing Coriolis flow sensors aim to magnify the flow sensitivity by shaping the tubing, and the corresponding fluid flow path, into favorable geometrical forms. However, in addition to improving the sensitivity of the Coriolis flow sensor measurement, the Coriolis flow sensor should also be robust against environmental disturbances that may impact the accuracy of sensor readings. Many approaches to modifying the geometric form of the tubing often result in large tubing loops that have no advantage in zero-point stability because external disturbances are also magnified (which in turn decrease sensor accuracy). Thus, the effective signal to noise ratio may remain the same. Further, these configurations also take up additional space in a fluid flow system, and looped geometric form modifies the fluid flow path; which influence pressure loss, flow velocity, shear rate, trappings, draining, and abrasion.

The present disclosure is directed to techniques for Coriolis flow sensing that include interfaces that facilitate coupling between a flow tube and an oscillator of a Coriolis flow sensor assembly. In general, the interface facilitates transmission of non-dissipative forces (e.g., drive oscillation imparted by the oscillator, and the Coriolis force), but limits the transmission of environmental disturbances (e.g., pressure and temperature) that may result in undesirable effects on the non-dissipative forces. Generally, the interface couples the oscillator and the flow tube, and the interface may be disposed between the flow tube and the oscillator and in certain embodiments, the flow tube may not directly contact the oscillator. The interface is disposed on the oscillator (i.e., may directly contact both the oscillator and the flow tube) and receives the flow tube (e.g., via suitable structural features that permit the flow tube to reside within or on the interface). According to the invention, the interface is connected to the oscillator at anchor points (e.g., fitting with hooks, screwed or bolted in, adhered) in order to reduce coupling points for mechanical deformation. The interface may include an adhesive and/or may couple to the flow tube through a friction fit. Moreover, the interface also contains structural features (rib/ribs) that couple (e.g., hold or contain) with the flow tube. The embodiments of the present disclosure are applicable to Coriolis flow sensor assemblies and system that incorporate such assemblies. Applications include life sciences, bioprocessing, clean room, food industry, pharmaceuticals, lab on a chip, oil and gas, water flow, and hydrogen pumping (high T gradient).

Turning now to the figures, <FIG> is a block diagram illustrating an embodiment of a Coriolis flow sensor system <NUM>. The Coriolis flow sensor system <NUM> includes electronic circuitry <NUM> coupled to a sensor assembly <NUM>. The sensor assembly <NUM> may, in certain embodiments, include a fluid flow assembly <NUM> that includes a flow tube <NUM> for retaining a fluid <NUM>. The fluid flow assembly <NUM> is coupled to the oscillator through an interface <NUM>; however, in certain embodiments not according to the claimed invention the interface may not be used <NUM>. In certain embodiments, sensor assembly <NUM> may include one or more actuators and one or more sensors <NUM>.

It would be appreciated by those skilled in the art that certain components of the sensor assembly <NUM> may be configured as disposable parts, and the others may be configured as re-usable resident parts. For example, at least one of the flow tubes, the one or more actuators, or the one or more sensors may be disposable parts, and other parts are configured as reusable resident parts. It would be appreciated by those skilled in the art that the disposable part(s) may be replaced at very low cost in intervals governed by the specific process needs. In addition, in some implementations, the material of the flow tube <NUM> may be changed (glass or polymer or silicone or metal), without the need for replacement of the entire Coriolis flow sensor. For example, the flow tube <NUM> may be disposable and releasable from the other components, which permits a relatively low cost component to be replaced with retaining the higher costs components. Accordingly, in certain embodiments, the flow tube <NUM> may be removed from the interface <NUM> by operator manipulation. In addition, in certain embodiments, the interface <NUM> may be swapped out depending on the characteristics of the fluid and/or the system <NUM> to achieve improved sensing for a particular system configuration. The disposable-part sub-system allows obtaining high accuracy measurements, reusing of part of the Coriolis flow sensor system <NUM>, provides a flexibility for single-use applications, and achieves cost and material savings.

Referring to <FIG>, in some embodiments, the flow tube <NUM> may be coupled with a mechanical oscillator <NUM> or form a unitary assembly with mechanical oscillator <NUM>. The one or more actuators <NUM> are used to induce oscillations of an appropriate amplitude over a required frequency range in the fluid <NUM> through the mechanical oscillator <NUM> and the flow tube <NUM>. The mechanical oscillator <NUM> and the actuator <NUM> are referred to collectively as the mechanical drive assembly <NUM>. The one or more sensors <NUM> are configured to provide signals indicative of a Coriolis response caused by the fluid <NUM> flowing through the flow tube <NUM>. The one or more sensors <NUM> may include, for example, electromagnetic sensors, or optical sensors, and associated components.

The flow tube <NUM> may be configured as a conduit with an internal passage that permits fluid flow and may be formed in a shape including, but not limited to single, dual or multi loop configurations, split flow, straight tube, counter- or co-flow configurations. In some implementations, the flow tube <NUM> is made from, for example, a polymer whose influence on the oscillation modes (harmonic frequencies) of the mechanical oscillator is not dominant. In some other examples, the flow tube <NUM> is made of metal. In yet other examples, the flow tube <NUM> is made of glass. The flow tube material, in some examples, is tailored to specific requirements of the bioprocessing application, such as temperature, pressure, and the characteristics of the fluid to be measured (e.g., corrosivity).

The Coriolis flow sensor system <NUM> also includes electronic circuitry <NUM> coupled to the sensor assembly <NUM>. The electronic circuitry <NUM> includes drive circuitry <NUM> to trigger the one or more actuator(s) <NUM> to generate oscillations in the flow tube <NUM> of the desired frequency and magnitude. The Coriolis flow sensor system <NUM> further includes sensor circuitry <NUM> to receive the Coriolis response from the flow tube <NUM>. The electronic circuitry <NUM> further includes a processor <NUM> to process the Coriolis response signals received from the sensors <NUM> to generate one or more measurements representative of one or more properties of the fluid. These measurements are displayed via a user interface <NUM>. The electronic circuitry <NUM> also includes a memory <NUM> to store the measurements for further use and communication, to store data useful for the drive circuitry <NUM>, and the sensor circuitry <NUM>.

In operation, the electronic circuitry <NUM> triggers the one or more actuator(s) to generate oscillations in the flow tube <NUM>, which are transferred to the fluid <NUM>. Due to these oscillations, the Coriolis response (vibration amplitude and phase) is generated in the fluid and is sensed by the sensors <NUM> through the flow tube <NUM>. The sensed Coriolis response signal from the sensors <NUM> are transmitted to the electronic circuitry <NUM> for further processing to obtain the measurements of the one or more properties of the fluid including fluid flow.

<FIG> illustrates an embodiment of a sensor assembly <NUM> that includes an interface <NUM>. The interface <NUM> couples the oscillator <NUM> to the flow tube(s) <NUM> (e.g., on a top surface <NUM> of the oscillator <NUM>). In certain embodiments, the interface <NUM> may connect to the oscillator <NUM> through an oscillator mount (e.g., connected with bolts or screws). In other embodiments, the interface <NUM> may include an adhesive. In general, the interface <NUM> separates the oscillator <NUM> from the one or more flow tubes <NUM> and may permit force transmission between the oscillator <NUM> and the flow tube <NUM>. As illustrated, the interface <NUM> is disposed continuously along the flow tube <NUM>; however, in certain embodiments, the interface <NUM> may only be disposed on a portion of the oscillator <NUM> and/or flow tube <NUM>, or at predetermined intervals (e.g., regular intervals, disposed at higher frequency towards the ends of the flow tube <NUM>). In the illustrated embodiment, the flow tubes <NUM> coupled to the oscillator <NUM> via the interface <NUM> are restrained or bent in a looped configuration. Accordingly, the interface <NUM> follows the desired shape of the flow tube <NUM> and may serve to retain the flow tube <NUM> in the desired shape. For example, the depicted interface <NUM> is configured in a U-shape. However, the flow tube <NUM> may also be provided as a generally straight conduit with a fluid flow path aligned along an axis, and, in such embodiments, the interface <NUM> may be shaped to accommodate a generally straight flow tube <NUM>. In any case, at least a portion of the interface <NUM> is positioned between the oscillator <NUM> and the flow tube <NUM> and serves to transfer oscillating forces and to protect against undesired disturbances. Further, in certain embodiments, the interface <NUM> may be configured as a reusable component configured to receive disposable flow tubes <NUM>. In other embodiments, the flow tube <NUM> may be attached or adhered to the interface <NUM>.

As provided herein, the interface <NUM> may decouple environmental disturbances or events, such as pressure and temperature changes, from the sensor assembly <NUM>. Several features of the present disclosure to reduce the effects of environmental disturbances are discussed below.

<FIG> shows heat flow in the direction of arrow <NUM> through a cross section of the flow tube <NUM> of the sensor assembly <NUM>. Temperature transmission through the flow tube walls <NUM> (which may be a function of wall thickness <NUM>), from the flow tube <NUM> to the oscillator <NUM> (thermal bridge) may change the dynamic behavior from parts of the oscillator <NUM> or induce local stress via thermal expansion of the oscillator structure. The flow tube <NUM> is separated from the oscillator <NUM> by the interface <NUM>, which reduces the heat transmission and therefore reduces potential changes to dynamic behavior of the oscillator <NUM>.

<FIG> illustrates fluid pressure (arrows <NUM>) on the walls <NUM> of the flow tube <NUM> of the sensor assembly <NUM>. During operation, the internal pressure from the flow tube <NUM> is transmitted to the oscillator <NUM> and may stretch/compress oscillator structures. In operation, this may result in a change of the dynamic behavior of the oscillating flow tube <NUM> or deformations in various spatial directions. These effects (e.g., change in dynamic behavior of the oscillating flow tube, deformations) may be addressed by oscillator geometries and signal post processing. As provided herein, the interface <NUM> used in conjunction with the sensor assembly. For example, the wall <NUM> of the flow tube <NUM> may experience a radial deformation (arrows <NUM>) due to pressure expansion. The intervening interface <NUM> does not transfer the stress to a transversal deformation along the backbone, which would affect the oscillation of the flow tube <NUM> (e.g., resulting in an oscillation that deviates from the drive oscillation imparted by the oscillator <NUM>).

In the embodiments depicted in <FIG>, the interface <NUM> is not flat, but has a round structure that receives (e.g., fits) around a portion of the flow tube <NUM>. Further, the interface <NUM> does not fully surround the flow tube <NUM> (e.g., is not a continuous shell). A continuous shell around the fluid containment (e.g., flow tube <NUM>) may permit temperature transmission from the oscillator that results in unpredictable oscillation modes (e.g., variation of e-modulus along the oscillator and local oscillator deformations).

<FIG> shows an embodiment of the interface <NUM> for coupling the flow tube <NUM> and the oscillator <NUM>. As shown, the interface <NUM> includes a structural component (multiple ribs <NUM>) that receives and retains the flow tube <NUM> in place. Upon assembly with the flow tube <NUM>, the ribs <NUM> partially surround the circumference of the flow tube <NUM> to reduce unpredictable oscillation modes and transmission of environmental disturbances. Further, the ribs <NUM> minimize the heat transfer. As illustrated, the ribs <NUM> are separated at constant intervals. However, in certain embodiments, the ribs may have any suitable spacing to permit increasing performance of the sensor assembly <NUM>. For example, more ribs <NUM> may be clustered towards the ends of the interface <NUM> and may be generally absent in the middle.

As illustrated, the oscillator includes anchor points <NUM> (e.g., holes), which reduces the number of coupling points for mechanical deformation. Further, the anchor points <NUM> permit oscillator and Coriolis force transmission but limit the deformation transfer. Additionally, it should be recognized by one of ordinary skill in the art that the embodiment of the present disclosure illustrated in <FIG> permits manufacturing oscillators <NUM> from sheet-based, e.g., sheet metals. The interface <NUM> may additionally or alternatively be manufactured from polymers. Further, a variety of interfaces <NUM> may be employed to couple various sizes and types of flow tubes <NUM> to one oscillator <NUM>, which increases the flexibility of the Coriolis flow sensing assembly of the present disclosure. Additionally, the oscillator <NUM> may include structural components <NUM> that damp modes of oscillations other than the main drive mode. <FIG> illustrates a flow tube <NUM> coupled to an oscillator <NUM> by an interface <NUM> with walls <NUM>. As illustrated, the walls <NUM> have a varying height <NUM>. As discussed above, it may be advantageous to have a non-continuous shell surrounding the flow tube <NUM>.

<FIG> illustrates an embodiment of the interface <NUM> for the sensor assembly <NUM>. As shown, the interface <NUM> includes an oscillator mount <NUM> that permits coupling between the interface <NUM> and the oscillator <NUM> by a bolt or screw. However, other coupling arrangements are contemplated. In the depicted embodiments, the interface <NUM> includes ribs <NUM> which may have variable geometry. For example, the ribs <NUM> may be thicker (i.e., wider) near the oscillator mount <NUM>. The interface <NUM> also includes a backbone <NUM>. As illustrated, the backbone <NUM> runs along the direction of flow <NUM> of the flow tube <NUM>. The implementation provides a minimized fixed coupling point <NUM> between the ribs <NUM> and the backbone <NUM>. Thus, the interface <NUM> may allow a radial deformation along arrows <NUM> due to pressure expansion of the tubing while not passing the stress to the oscillator <NUM> due to transversal deformation along the backbone <NUM>. Further, the backbone <NUM> permits controlled heat flow along its length in the direction of flow <NUM>. The backbone <NUM> may be an open frame backbone <NUM> with rails <NUM> that are spaced apart and that define openings <NUM> that align with the rib spacing. The open frame structure may also improve heat flow.

<FIG> depicts an embodiment of the interface <NUM>. The depicted interface <NUM> includes the backbone structure <NUM> with spaced-apart ribs <NUM> and the oscillator mount <NUM>. As discussed, the mounting or coupling to the oscillator <NUM> may be any suitable structure, and the depicted oscillator mount <NUM> is by way of example only. The structure of the interface <NUM> reduces the surface in direct contact with the exterior surface of the flow tube <NUM> in order to control the transmission of force and temperature along the oscillator. For example, the ribs <NUM> are spaced apart to interrupt the direct contact of the interface with the flow tube <NUM>. The contact area is suitable enough to permit a good oscillation/Coriolis force transmission from the oscillator <NUM> to the flow tube <NUM> via the interface <NUM>. Further, the heat capacity is minimized to permit the flow tube <NUM> to quickly adapt to transient thermal events.

The backbone structure <NUM> includes spaced-apart rails that are generally aligned in a direction along the flow axis <NUM>. Further, the thickness of each rail <NUM> and the distance between them may vary to create different stiffness effects along the axis <NUM>. <FIG> shows the interface <NUM> of <FIG> coupled to the flow tube <NUM>. Clips <NUM> disposed at the ends of the interface <NUM> (e.g., on the oscillator mount <NUM>) may provide greater retaining force at the interface oscillator mount point. The interface <NUM> may be arranged to permit overhang of the fluid entry point <NUM> and the fluid exit point <NUM> to permit coupling of the flow tube <NUM> to other tubing of the system <NUM>. <FIG> shows the interface <NUM> of <FIG> fixed to an oscillator <NUM>.

<FIG> various embodiments of interfaces <NUM> for coupling the oscillator <NUM> to the flow tube <NUM> in accordance with the present disclosure. Moreover, while the shape of the flow tubes <NUM> shown in <FIG> is a bent shape, any shape (e.g., straight or looped) may be incorporated in a Coriolis sensing assembly in accordance with the present techniques.

<FIG> shows the flow tube <NUM> coupled to a metal oscillator <NUM> by an adhesive (e.g., glue) interface <NUM>. <FIG> shows the flow tube <NUM> coupled to a polymer oscillator <NUM> through metal clips <NUM>. <FIG> shows the flow tube <NUM> coupled to a polymer oscillator <NUM> with a wire wrap <NUM>. The sensor assemblies <NUM> depicted in <FIG> may have variable performance. For example, <FIG> wire wrap showed superior performance relative to the metal clips and the adhesive. It should be appreciated by one of ordinary skill in the art that any combination of these techniques may be incorporated into a sensor assembly <NUM>. For example, an adhesive interface <NUM> may be disposed between the flow tube <NUM> and the oscillator <NUM> in addition to the wire wraps <NUM>. Moreover, the adhesive interface may be disposed at intervals along the direction of the flow, rather than continuously disposed.

<FIG> shows various interfaces <NUM> for coupling the flow tube <NUM> and the oscillator <NUM> of a Coriolis flow sensor assembly <NUM> in accordance with the present disclosure. <FIG> shows a bent silicone flow tube <NUM> coupled to the oscillator <NUM> through a polymer interface <NUM>. <FIG> shows a hybrid metal/polymer oscillator directly coupled to the silicone flow tube <NUM>. As shown, there is no separate interface <NUM>, however, the oscillator <NUM> includes structural features (e.g., walls) that enable the oscillator <NUM> and flow tube <NUM> to couple such that the oscillator <NUM> receives the flow tube <NUM> between the walls <NUM>. Further, as shown, the walls <NUM> have a varying height, which may permit certain advantages as described herein. <FIG> shows an interface having a backbone, which demonstrated superior performance to the interfaces <NUM> shown in <FIG>.

Some applications for the disposable-part sub-system described herein include fabrication of wafers in semi-conductor industry, and medical applications that involve use of organic fluids. Some of these are high purity applications and use of flow conduit made of for example polymer, or other chemically inert material is advantageous in such applications, and in some other applications electrically inert and low thermal conductivity material like glass is advantageous.

This disclosure relates to a sensor assembly of a Coriolis flow sensor system with an interface that permits transmission of the drive oscillation and the Coriolis force, but limits the transmission of environmental disturbances that may negatively influence the drive oscillation of the flow tube. As discussed above, the interface may be disposed between a flow tube and an oscillator of the Coriolis flow sensor system. Moreover, the interface may be positioned between the flow tube and oscillator, disposed at the ends of a region between the flow tube and the oscillator, or at intervals along the region. The interface may include structural features that facilitate coupling between the interface and the oscillator (e.g., hooks, bolts, screws, adhesive material). Further, a portion of the interface that receives the flow tube may be flat or may partially surround a portion of the perimeter (e.g., circumference) of the flowtube. The interface may include (e.g., separately or be attached to) structural components that facilitate retaining of the flow tube as well as permit coupling between the flow tube, interface, and oscillator.

Claim 1:
A Coriolis flow sensor system (<NUM>) comprising:
a fluid flow assembly (<NUM>) comprising:
a flow tube (<NUM>) configured to provide a flow path through the flow tube (<NUM>);
a mechanical drive assembly (<NUM>) configured to drive an oscillation of the flow tube (<NUM>) while fluid (<NUM>) is flowing, wherein the mechanical drive assembly (<NUM>) comprises an oscillation surface; and
an interface (<NUM>) fixedly coupled to the oscillation surface of the mechanical drive assembly (<NUM>) and configured to receive the flow tube (<NUM>) such that at least a portion of the interface (<NUM>) is in direct contact with the flow tube (<NUM>) and such that the interface (<NUM>) transfers oscillation forces of the oscillation surface to the flow tube (<NUM>);
wherein the oscillation surface of the mechanical drive assembly (<NUM>) comprises a plurality of anchor points (<NUM>) for connecting the interface (<NUM>) thereto, and
the interface (<NUM>) is coupled to the fluid flow assembly (<NUM>) with one or more rib structures (<NUM>) or with one or more wall features (<NUM>), disposed along the interface (<NUM>) in a direction of the flow path.