HK1124915B - Magnet assembly - Google Patents

Description

Magnet device

Technical Field

The invention relates to a magnet device, in particular to a magnet device applied under high temperature.

Background

US4491025 to j.e.smith et al, published 1/1985, and re.31450 to j.e.smith, published 11/1982, disclose the use of Coriolis (Coriolis) mass flowmeters to measure the mass, density and volumetric flow of a fluid flowing through a conduit, as well as other information about the fluid. These meters have one or more flow tubes of different configurations. Each conduit structure may be viewed as having a set of natural modes including, for example, pure flexural, torsional, radial, and coupled modes. In a typical coriolis mass flow measurement application, a conduit structure is excited in one or more modes of vibration as a fluid flows through the conduit, and motion of the conduit is measured at equidistant points along the conduit.

The mode shape of the system filled with the fluid is defined in part by the combination of the mass of the flow tube and the fluid within the flow tube. Fluid flows into the flow meter from a conduit associated with an inlet side of the flow meter. The fluid then flows directly through the flow tube or tubes and out of the flow meter into a conduit associated with the outlet side.

An actuator (DRIVER) is used to apply an exciting force to the flow tube. The exciting force oscillates the flow tube. When no fluid flows through the flowmeter, all points along the flow tube oscillate at the same phase. As fluid begins to flow through the flow tube, coriolis accelerations cause each point along the flow tube to have a different phase relative to other points along the flow tube. The phase on the inlet side of the flow tube lags the driver and the phase on the outlet side advances the driver. Sensors at different points of the flow tube produce sinusoidal signals representative of the motion of the flow tube at the different points. Wherein the phase difference between the two sensor signals is proportional to the mass flow rate of the fluid flowing through the flow tube or flow tubes.

The flow tube driver typically includes a coil opposite a fixed magnet. The coil and the fixed magnet are attached to a pair of flow tubes or a flow tube and balance bar. In operation, the magnetic field in the actuator coil is rapidly changed. The fixed, opposing magnetic poles assist in generating an excitation force that selectively gathers or separates the flow tubes.

Likewise, the sensors of the flow meter may include an electromagnetic coil sensor and an opposing magnet, one or both of which are attached to the flow tube as described above. In operation, the electromagnetic coil sensor generates a substantially sinusoidal signal from the moving magnet as the flow tube oscillates.

The flow meter can measure the flow rate of a fluid in high temperature applications. Some flow meters need to be used continuously at or above 400 degrees fahrenheit. In the prior art, magnets used as actuators and/or sensor devices are held in a magnet holder by means of shrink fit. And the magnet holder is attached to the flow tube.

In the prior art, aluminum-nickel-cobalt (AlNiCo) magnets are used at high temperatures where the flow tube stiffness is low and the resulting amplitude is high. A drawback of using AlNiCo magnets is that the AlNiCo magnets have a greater mass than other magnets when their B field strength is relatively low. However, in the design of the new flow meter, the stiffness is high and the amplitude is low. Thus, the design of new flowmeters requires low mass actuator and sensor systems for proper operation. Since the distance between the supports is fixed by the design of the flowmeter, it is not practical to simply take a larger magnet.

Disclosure of Invention

According to any of the embodiments of the present invention, a magnet apparatus is provided to solve the above and other problems and achieve technical effects better than those of the prior art.

According to an embodiment of the present invention, a magnet apparatus is provided. The magnet arrangement comprises at least one magnet; a magnet holder comprising a generally planar magnet receiving face for receiving the at least one magnet; and brazing securing the at least one magnet to the magnet receiving face of the magnet holder.

According to an embodiment of the present invention, a magnet apparatus is provided. The magnet arrangement comprises at least one magnet; a magnet holder for receiving the at least one magnet; a countersink region formed in said magnet keeper, wherein said countersink region is configured to receive said at least one magnet; and brazing to secure the at least one magnet to the countersink region of the magnet keeper.

According to an embodiment of the present invention, a magnet apparatus is provided. The magnet arrangement comprises at least one magnet; a magnet holder comprising a generally planar magnet receiving face for receiving the at least one magnet; and a nickel plating layer that fixes the at least one magnet to the magnet receiving face of the magnet holder.

According to an embodiment of the present invention, a method of forming a magnet apparatus is provided. The method includes mounting the at least one magnet to a magnet holder. The magnet retainer includes a generally planar magnet receiving face for receiving the at least one magnet. The method further includes brazing the at least one magnet to the magnet holder. Securing a suitable magnet holder to the oscillating flow meter.

According to an embodiment of the present invention, a method of forming a magnet apparatus is provided. The method includes mounting the at least one magnet to a magnet holder. The magnet retainer includes a generally planar magnet receiving face for receiving the at least one magnet. The method further includes nickel plating the at least one magnet to the magnet holder. Securing a suitable magnet holder to the oscillating flow meter.

Various aspects of the invention

In one aspect of the magnet assembly, the at least one magnet comprises a samarium cobalt magnet.

In another aspect of the magnet assembly, the at least one magnet is comprised of a nickel-plated samarium cobalt magnet.

In yet another aspect of the magnet assembly, the magnet receiving surface includes a countersink region formed in the magnet keeper, wherein the countersink region is configured to receive the at least one magnet.

In yet another aspect of the magnet assembly, the magnet assembly further includes a pole piece secured to the at least one magnet.

In yet another aspect of the magnet assembly, the magnet assembly further comprises a pole piece secured to the at least one magnet, wherein the pole piece comprises a brazed aperture.

In one aspect of the method, the at least one magnet is comprised of a samarium cobalt magnet.

In another aspect of the method, the at least one magnet is comprised of a nickel-plated samarium cobalt magnet.

In yet another aspect of the method, the magnet receiving surface includes a countersink region formed in the magnet keeper, wherein the countersink region is configured to receive the at least one magnet.

In yet another aspect of the method, the method further comprises securing a magnetic pole to the at least one magnet.

However, in another aspect of the method, the method further comprises re-magnetizing the magnet assembly.

Drawings

Like reference symbols in the various drawings indicate like elements.

FIG. 1 illustrates a flow meter including a meter assembly and meter electronics;

FIG. 2 illustrates a magnet assembly for an oscillating flow meter according to an embodiment of the invention;

FIG. 3 is a cross-sectional view AA of the magnet assembly shown in FIG. 2;

FIG. 4 illustrates a magnet assembly according to an embodiment of the present invention;

fig. 5 is a BB cross-sectional view of the magnet assembly shown in fig. 4.

Detailed Description

Those of ordinary skill in the art will understand how to make and use the best mode of the present invention based on the accompanying figures 1-5 and the following detailed description of the preferred embodiments. For the purposes of understanding the principles of the invention, certain conventional aspects have been simplified or omitted. Variations of embodiments that would benefit from the present invention are within the scope of those skilled in the art. The technical features described below can be combined in different ways by a person skilled in the art to form a plurality of variants of the invention. Therefore, the scope of the present invention should be determined not only by the specific embodiments described below but also by the appended claims and their equivalents.

Fig. 1 shows a flow meter 5 comprising a meter arrangement 10 and meter electronics 20. The meter device 10 is responsive to the mass flow rate and density of the working fluid. Meter electronics 20 is connected to meter assembly 10 by leads 100 for providing density, mass flow rate, and temperature information through path 26, among other information. Although the structure of a coriolis flowmeter is clear to one skilled in the art, the present invention is described for use as a coriolis mass flowmeter that oscillates tube densitometer without other measurement capabilities.

Meter assembly 10 includes a pair of manifolds 150 and 150 ', flanges 103 and 103' having flange necks 110 and 110 ', a pair of parallel flow tubes 130 and 130', a drive mechanism 180, a temperature sensor 190, and a pair of velocity sensors 170L and 170R. Flow tubes 130 and 130 'have two substantially linear inlet legs 131 and 131' and outlet legs 134 and 134 'facing flow tube mounts 120 and 120', respectively. The flow tubes 130 and 130' are bent at two symmetrical positions along their length and are substantially parallel to each other throughout their length. Support bars 140 and 140 'serve to define the oscillation of each flow tube about the axes W and W'.

The side brackets 131, 131 ' and 134, 134 ' of the flow tubes 130 and 130 ' are fixedly attached to flow tube mounts 120 and 120 ', which in turn are fixedly attached to manifolds 150 and 150 '. This provides a continuous closed fluid path through coriolis meter device 10.

When flanges 103 and 103 ' having communication holes 102 and 102 ' carry the measured working fluid through inlet end 104 and outlet end 104 ' into a working pipe (not shown), the fluid enters inlet end 104 of the meter through orifice 101 of flange 103 and is directed into branch 150 and then toward flow tube mount 120 having surface 121. The fluid in the branch 150 is split and flows through flow tubes 130 and 130', respectively. After exiting the flow tubes 130 and 130 ', the working fluid is recombined in a single flow path in branch 150 ' and then flows to the outlet end 104 ' (connected by flange 103 ' having screw holes 102 ') and into the working channel (not shown).

Flow tubes 130 and 130 ' having substantially the same young's modulus are selected and appropriately mounted to the flow tube mounts 120 and 120 ' so as to have substantially the same mass distribution, moment of inertia, and system stiffness about bending axes W-W and W ' -W ', respectively. The bending axes pass through the support rods 140 and 140', respectively. The young's modulus of the flow tube changes with temperature changes and this change affects the flow and density calculations, and a resistance temperature sensor (RTD)190 may be mounted on the flow tube 130' for continuously measuring the temperature of the flow tube. Thus, the temperature of the flow tube and the voltage flowing from the flow tube through the RTD are regulated by the temperature of the fluid passing through the flow tube. The voltage dependent temperature through the RTD is applied in a well known manner, compensating for changes in the elastic modulus of flow tubes 130 and 130' due to changes in flow tube temperature by meter electronics 20. The RTD is connected to meter electronics 20 via lead 195.

Both flow tubes 130 and 130 'are excited in opposite directions by driver 180 about their respective bending axes W and W', which is referred to as the first out of phase bending mode of the meter. The drive mechanism 180 may be comprised of any one of a number of well known devices such as a magnet mounted to the flow tube 130' and an opposing coil mounted to the flow tube 130 and through which a varying current is passed by oscillating the two flow tubes. An appropriate excitation signal via meter electronics 20 is applied to excitation mechanism 180 via lead 185.

Meter electronics 20 receives the RTD temperature signal on lead 195 and generates the left and right velocity signals on leads 165L and 165R, respectively. The meter electronics 20 generates a drive signal on the lead 185 that acts on the drive mechanism 180 and oscillates the flowtubes 130 and 130'. Meter electronics 20 processes the left and right velocity signals and the RTD signal for calculating the mass flow rate and density of fluid flowing through the meter device 10. This information, along with other information, is taken by meter electronics 20 and communicated to utilization device 29 via path 26.

Fig. 2 shows a magnet arrangement 200 according to an embodiment of the invention. The magnet assembly 200 includes at least one magnet 210 and a magnet holder 220. In one embodiment, the magnet assembly 200 is used in a meter assembly 10 of an oscillating flow meter 5. The oscillatory flow meter 5 can consist, for example, of a coriolis flow meter or an oscillatory densitometer.

The magnet 210 can be part of the meter excitation mechanism 180 or part of the meter sensor 170 (see fig. 1). The magnet 210 is shown in this embodiment as being generally cylindrical. However, other magnet shapes may be employed.

The magnet 210 may include one or more magnet elements. For example, the magnet 210 may be comprised of a set of magnets brazed together.

The magnet 210 in one embodiment is comprised of a samarium cobalt magnet (SmCo). SmCo magnets substantially retain their original magnetic properties at high temperatures and are therefore advantageous for use in flow meters that receive high temperature flow fluids. For example, at or above 400 degrees fahrenheit, a SmCo magnet may produce a satisfactory magnetic flux needed in a flow tube driver or flow tube sensor. However, it should be understood that other magnet materials, such as AlNiCo magnets, may be used and are within the scope of the description and claims.

The magnet keeper 220 may comprise one or more keeper element portions. The magnet holder 220 includes a magnet receiving surface 222 for receiving the magnet 210. In one embodiment, the magnet receiving surface 222 is substantially planar. The magnet holder 220 may further include a wall 224 and a mount 226. The wall 224 may surround the magnet 210, but not be in contact with the magnet 210. There is a gap G (see fig. 3) between the magnet 210 and the wall 224, wherein a portion of the respective actuator or sensor element can move into and out of the gap G. Thus, the wall 224 may confine the magnetic flux to a proximity region between the magnet 210 and the respective actuator or sensor element.

It should be understood that the wall 224 is not an essential component of the magnet holder 220. The magnet keeper 220 may comprise only some basic component, wherein the gap G is formed between the magnet 210 and other elements.

In one embodiment, the magnet is nickel plated. The nickel plating layer extends beyond at least a portion of the magnet 210 and beyond at least a portion of the magnet receiving face 222 of the magnet holder 220. The nickel-plated layer is used to improve the high temperature performance of samarium cobalt magnets. Additionally, the nickel plating may provide some or all of the securement. For example, in one embodiment of forming the magnet assembly 200, the magnet 210 is mounted to the magnet receiving surface 222, and then the entire magnet assembly 200 is nickel-plated. In this embodiment, a subsequent nickel plating layer secures the magnet 210 to the magnet holder 220.

This figure also shows an optional pole 211 fixed to the magnet 210. The magnetic pole 211 may be composed of an additional magnet. Alternatively, the magnetic pole 211 may be comprised of a magnetically conductive material that is used to form or conduct the magnetic flux from the magnet 210 to the wall 224. The pole piece 211 may include a hole 212 that brazes (or otherwise secures) the pole piece 211 to the magnet 210. Additionally, the pole piece 211 may further include a flange 213 that substantially mates with the magnet 210.

Fig. 3 is a cross-sectional view AA of the magnet assembly 200 shown in fig. 2. The cross-sectional view shows the brazing 230 securing the magnet 210 to the magnet receiving face 222 of the magnet holder 220. The brazing 230 includes fusing the same or different metals with a molten filler metal. Brazing typically uses filler metals including some sort of bronze. However, brazing may also be used with a variety of metals, including red copper, nickel, zinc, silver, and phosphorus. Brazing does not melt the brazed basic metal pieces, but rather the filler metal that is dispersed by capillary action. At its liquidus temperature, the molten filler metal interacts with the thin layer of base metal and then cools to become exceptionally hard, forming a hermetic joint due to the interaction of the grain structure. While some brazes are considered to include temperatures as low as 450 degrees fahrenheit, typical brazes require temperatures of 900 degrees fahrenheit and 2200 degrees fahrenheit.

This figure shows the mount 226 in further detail, according to an embodiment of the invention. The mount 226 in the embodiment shown includes a coupling aperture 228. The attachment holes 228 can be used to secure or removably secure the magnet holder 220 to a flow tube or flow tube structure. The attachment bore 228 is shown in this embodiment as having threads that accept a threaded fastener of some sort. However, it should be understood that the coupling aperture 228 and the entire mounting member 226 can take virtually any form of construction that is secured to the flow meter.

Fig. 4 shows a magnet arrangement 220 according to an embodiment of the invention. In this embodiment, the magnet receiving face 222 includes a counterbore portion 229 configured to receive the magnet 210. The countersink region 229 aids in locating and mounting the magnet. The countersink region 229 may function well for the magnet 210 in the middle of the magnet keeper 220. In addition, the countersink region 229 can provide more area for brazing the magnet 210 to the magnet keeper 220.

Fig. 5 is a BB cross-sectional view of the magnet assembly 200 depicted in fig. 4. The cross-sectional view shows the magnet 210 positioned in the countersink region 229. Brazing 230 secures the magnet 210 to the countersink region 229 and to the magnet keeper 220. As can be seen in the figures, the countersink region 229 can be substantially planar. Also as can be seen in the figures, the countersink region 229 can generally match the shape of the magnet 210. Additionally, the countersink region 229 can include any manner of grooves 234 that provide additional braze volume. Alternatively, the grooves 234 may include any form of ridge (ridge), roughening (R0UGHENING), structuring (TEXTURING), and the like.

The magnet assembly 200 according to any of the embodiments may be made in a variety of ways. In one approach, the magnet 210 is mounted against and brazed to the magnet receiving face 222 of the magnet holder 220. In another approach, the magnet 210 is mounted in and brazed to the countersink region 229 of the magnet keeper 220. In another approach, the uncharged magnets are plated to secure the components together. Next, the brazed or electroplated device may be remagnetized. The remagnetization is performed in order to substantially recover the magnetic susceptibility lost due to heating during the brazing process.

The magnet arrangement according to the invention can be implemented as any one of the embodiments chosen to provide different advantages, if desired. The invention provides a high temperature magnet assembly for an oscillating flow meter. The present invention provides a high temperature magnet assembly for use in a flow tube driver system or a flow tube sensor system. The present invention provides a strong and efficient magnet mounting method for an oscillating flow meter. The invention provides a high-temperature magnet device adopting samarium-cobalt magnets. The invention provides a high-temperature magnet device of a samarium cobalt magnet adopting a nickel-plated layer. The present invention provides a magnet mounting method for a samarium cobalt magnet wherein the magnet is mounted on the magnet without the application of pressure. The invention provides a high-temperature magnet device without increasing the size of the magnet.

Claims (17)

1. A magnet assembly (200) comprising at least one magnet (210) and a magnet keeper (220) comprising a generally planar magnet receiving surface (222) for receiving the at least one magnet (210), the magnet assembly (200) further comprising:

a brazing portion (230) for securing the at least one magnet (210) to the magnet receiving face (222) of the magnet holder (220).

2. The magnet assembly (200) of claim 1, wherein the at least one magnet (210) is comprised of a samarium cobalt magnet.

3. The magnet assembly (200) of claim 1, wherein the at least one magnet (210) is comprised of a nickel-plated samarium cobalt magnet.

4. The magnet assembly (200) of claim 1, wherein the magnet receiving surface (222) comprises a countersink region (229) formed in the magnet keeper (220), wherein the countersink region (229) is configured to receive the at least one magnet (210).

5. The magnet assembly (200) of claim 1, further comprising a pole piece (211) secured to the at least one magnet (210).

6. The magnet assembly (200) of claim 1, further comprising a pole piece (211) secured to the at least one magnet (210), wherein the pole piece (211) comprises a braze hole (212).

7. A magnet arrangement (200) comprising at least one magnet (210) and a magnet holder (220) for receiving the at least one magnet (210), characterized in that the magnet arrangement (200) further comprises:

a countersink region (229) formed in said magnet keeper (220), wherein said countersink region (229) is configured to receive said at least one magnet (210); and

securing the at least one magnet (210) to a brazed portion (230) of the countersink region (229) of the magnet keeper (220).

8. The magnet assembly (200) of claim 7, wherein the at least one magnet (210) is comprised of a samarium cobalt magnet.

9. The magnet assembly (200) of claim 7, wherein the at least one magnet (210) is comprised of a nickel-plated samarium cobalt magnet.

10. The magnet assembly (200) of claim 7, further comprising a pole piece (211) secured to the at least one magnet (210).

11. The magnet assembly (200) of claim 7, further comprising a pole piece (211) secured to the at least one magnet (210), wherein the pole piece (211) comprises a braze hole (212).

12. A method of forming a magnet assembly comprising mounting at least one magnet to a magnet holder, wherein the magnet holder comprises a substantially planar magnet receiving face for receiving the at least one magnet,

characterized in that the method further comprises: brazing the at least one magnet to the magnet holder, wherein the magnet holder is secured to the oscillating flow meter.

13. The method of claim 12, wherein the at least one magnet is comprised of a samarium cobalt magnet.

14. The method of claim 12, wherein the at least one magnet is comprised of a nickel-plated samarium cobalt magnet.

15. The method of claim 12, wherein the magnet receiving surface comprises a countersink region formed in the magnet keeper, wherein the countersink region is configured to receive the at least one magnet.

16. The method of claim 12, further comprising securing a pole to the at least one magnet.

17. The method of claim 12, further comprising re-magnetizing the magnet assembly.