The present invention relates generally to sensors for measuring fluids, more particularly, to magnetic flowmeter assemblies for flow and temperature measurement.
Temperature measurements are often made as secondary measurements with other types of analytical or physical probes measuring a fluid flow characteristic or property. Such temperature measurements will often be accomplished using a separate measuring element, or with a measuring device that is embedded in the internal portions of the other analytical/physical probes. Examples can include pH electrodes that include an embedded RTD or thermistor. Specifically, an RTD can be included within a capillary tube within the glass measuring element of a pH sensor. Other examples can include a thermowell, which comprises a metal tube with a temperature measuring element located within, wherein the thermowell can act as a solution ground electrode by having an electrical connection attached to it.
Flow sensor assemblies using electrodes, such as magnetic flowmeters, can benefit from measuring the temperature of the fluid with the flow rates. Benefits include using the temperature for process control, system safety, and media transport efficiency. For example, in some pumped systems operating on flow control, an increase in the downstream backpressure may result in excessive energy to be consumed by the pump(s) in order to maintain the desired flow rate. The increased energy consumption can lead to a rise in fluid temperature, which can be indicative of inefficient operating characteristics in the fluid system, i.e. inefficient energy consumption by the pump. As such, measuring the temperature at various locations in a fluid transport system provides smart temperature analysis that could lead to significant energy savings, e.g. by increased fluid media transport efficiency.
Other benefits include using temperature measurements when conducting flow diagnostics in conjunction with empty pipe information, specifically providing additional information to help distinguish between a partially or fully empty pipe. Moreover, temperature measurements can increase accuracy of the fluid flow rate measured by compensating for thermal expansion of the piping.
However, such benefits of measuring temperature with the flow rate often requires a separate means for obtaining the temperature information. One example is to use a thermowell, which requires an additional hole within the piping for inserting the thermowell, thereby increasing the risk for a leak to occur at the insertion point. Another example is to mount a probe on the outside of the piping; however, such a configuration can slow down the temperature response of the sensing element, and thereby decreases accuracy.
It should, therefore, be appreciated there remains a need for accurately measuring the temperature and fluid flow rate simultaneously that addresses these concerns. The present invention fulfills these needs and others.
Briefly, and in general terms, a magnetic flowmeter assembly is provided having electrodes disposed about a tubular body, wherein at least one of the electrodes includes a temperature sensing element inserted therein. The magnetic flowmeter assembly is configured to measure the flow rate of fluid flowing through the tubular body. The temperature sensing element can be inserted within an electrode such that it is well heatsinked to the electrode surface in contact with the fluid flow, thus placing the temperature sensing element in effective thermal contact with the fluid. As such, the magnetic flowmeter assembly enables simultaneous measurement of the fluid flow rate and fluid temperature.
In a detailed aspect of an exemplary embodiment, the tip of the temperature sensing element can be embedded as deep as possible within the electrode, such that it is in thermal contact with a contact end of the electrode. Moreover, the electrode can include heat conductive filling to secure and retain the temperature sensing element within the electrode, to effectual thermal conductivity therebetween.
In another detailed aspect of an exemplary embodiment, the temperature sensing element is electrically coupled to an electronics assembly for determining the fluid temperature, wherein the temperature sensing element is electrically isolated from said fluid. Moreover, any electrode on a magnetic flowmeter, e.g. measuring electrode, auxiliary electrode and so on, can act as a thermowell to house a temperature sensing element that is isolated from the fluid.
In another detailed aspect of an exemplary embodiment, the magnetic flowmeter assembly is full-bore, wherein the tubular body is configured to attach inline within a fluid flow system. A pair of coil assemblies is coupled to the tubular body in an intermediate region thereof. The pair of coil assemblies is each disposed external to the tubular body on opposing sides of the body aligned along an axis (Az), to generate a magnetic field within the fluid flow path of the tubular body. A pair of measuring electrodes is attached to the tubular body, coupled to a corresponding aperture defined by the body. Each measuring electrode of the pair of electrodes is in electrical communication with the fluid within the flow path. The pair of electrodes are aligned along an axis (Ay) orthogonal to the longitudinal axis (Ax) and orthogonal to the axis (Az). A plurality of auxiliary electrodes are attached to the tubular body, including a first auxiliary electrode and a second auxiliary electrode that are disposed upstream of the pair of measuring electrodes.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment disclosed.
Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which:
In certain embodiments of the present invention, the magnetic flowmeter assembly can be configured as described and claimed in Applicant's co-pending patent applications: 1) entitled “FULL BORE MAGNETIC FLOWMETER ASSEMBLY,” U.S. application Ser. No. 16/146,090, filed Sep. 28, 2018, 2) entitled “MAGNETIC FLOWMETER ASSEMBLY HAVING INDEPENDENT COIL DRIVE AND CONTROL SYSTEM”, U.S. application Ser. No. 16/243,868, filed Jan. 9, 2019, 3) entitled “MAGNETIC FLOWMETER WITH MEDIA CONDUCTIVITY MEASUREMENT”, U.S. application Ser. No. 16/243,980, filed Jan. 9, 2019, and 4) entitled “MAGNETIC FLOWMETER ASSEMBLY WITH ZERO-FLOW MEASUREMENT CAPABILITY”, U.S. application Ser. No. 16/244,060, filed Jan. 9, 2019, which are hereby incorporated by reference for all purposes.
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The magnetic flowmeter assembly 10 further includes a plurality of auxiliary electrodes 70 (c-e), including a first auxiliary electrode 70(c) and a second auxiliary electrode 70(d) that are disposed upstream of the pair of measuring electrodes 70 (a, b). The first and the second auxiliary electrodes are aligned with the axis (Az), on opposing sides of the pipe, such that axis (Ay) and axis (Az) are coplanar. The first and second auxiliary electrodes (70c, d) can be used to determine the pipe as being full, empty, or partially full. A temperature sensing element disposed within the first and/or second auxiliary electrode 70 (c, d) can provide additional information that enable distinguishing between a partially or fully empty pipe. For example, a sudden change in the temperature measured, corroborated with the empty pipe detection, can improve the validity that a partially empty pipe has become totally empty. A third auxiliary electrode 70(e) can also be disposed downstream of the pair of measuring electrodes 70 (a, b). The measuring electrodes and the auxiliary electrodes are each mounted to a corresponding aperture 20 (a-e) formed in the wall of the pipe 12.
The tubular body, i.e. pipe 12, is formed of thermoplastic material, e.g., such as chlorinated polyvinyl chloride (CPVC), polyvinyl chloride (PVC), or polyvinylidene fluoride (PVDF). Preferably, the pipe is formed of the same pipe used in other portions of the fluid flow system (not shown), to include the type of pipe material (e.g., CPVC, PVC or PVDF) and size (e.g., pipe diameter). End connectors (
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The brace 22 further serves as magnetic circuitry for the magnetic field generated by the coils 14. The brace has a generally octagonal shape, which benefits assembly and operation of the assembly 10. More particularly, the brace 22 is formed of two, generally c-shaped components 28 that slidably mate with each other about the pipe, to couple to each other. In this manner, the brace 22 can be used on pipes having different diameters. Attachments (e.g., bolts) couple the coils to the brace along the axis (Az).
The assembly 10 is configured to generate a strong alternating magnetic field (flux) B that is distributed evenly over the pipe cross-section. Utilizing an alternating magnetic field avoids electrode material migration. Configuration of the brace 22, e.g., including shape and materials, facilitates the resulting magnetic field (flux) B within the pipe 12. In the exemplary embodiment, the brace 22 is formed of “soft” magnetic materials, which refers to relative permeability, meaning it has no remnant magnetization when shut down.
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In a method of manufacture, a pipe 12 is selected having the same parameters of other portions of the fluid flow system. The pipe is cut to a prescribed length (L) to accommodate the desired location of the sensor assembly 10 within the fluid flow system. Then, apertures 20 (a-e) are drilled in the pipe at the desired locations of the electrodes. The electrodes 70 (a-e) are then mounted in place.
It should be appreciated from the foregoing that the invention provides a magnetic flowmeter assembly having electrodes disposed about a tubular body, wherein at least one of the electrodes includes a temperature sensing element inserted therein. The magnetic flowmeter assembly is configured to measure the flow rate of fluid flowing through the tubular body using electrodes and a pair of coil assemblies that are configured to generate a magnetic field. The temperature sensing element can be located sufficiently close to a contact end of an electrode so as to be well heatsinked to said contact end without actual contact with the fluid flow. As such, the magnetic flowmeter assembly enables simultaneous measurement of the fluid flow rate and fluid temperature.
The present invention has been described above in terms of presently preferred embodiments so that an understanding of the present invention can be conveyed. However, there are other embodiments not specifically described herein for which the present invention is applicable. Therefore, the present invention should not to be seen as limited to the forms shown, which is to be considered illustrative rather than restrictive.