CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

62/978,599, filed February 19, 2020, the entire disclosure of which is hereby incorporated by reference, and U.S. Non-Provisional Application No. 16/918,455, filed July 1, 2020, the entire disclosure of which is hereby incorporated by reference.

FIELD

[0002] The present invention relates generally to a magnetostrictive transmitter, and, more particularly, to a sensor assembly for a magnetostrictive transmitter with a piezoelectric crystal including a groove for receiving a magnetostrictive wire.

BACKGROUND

[0003] Magnetostrictive transmitters are known. Known magnetostrictive transmitters include a piezoelectric crystal. Known magnetostrictive transmitters also include a magnetostrictive wire. Difficulties can arise in the piezoelectric crystal sensing movement of the magnetostrictive wire.

SUMMARY

[0004] The present invention provides a sensor assembly for a magnetostrictive transmitter. [0005] In an exemplary embodiment, the sensor assembly for a magnetostrictive transmitter comprises a holder, a substrate, a piezoelectric crystal, and a magnetostrictive wire. The holder is formed from a non-conductive material. The holder includes an inner surface and an outer surface. The holder further includes an upper surface and a lower surface. The substrate is formed from a non-conductive material. The substrate includes an inner surface and an outer surface. The substrate further includes an upper surface and a lower surface. The substrate is operable to be received in the holder with the outer surface of the substrate opposing the inner surface of the holder. The piezoelectric crystal includes an inner surface and an outer surface. The piezoelectric crystal further includes an upper surface and a lower surface. The piezoelectric crystal further includes a groove extending in the inner surface from the upper surface through the lower surface. The piezoelectric crystal is operable to be mounted to the substrate with the outer surface of the piezoelectric crystal opposing the inner surface of the substrate. The magnetostrictive wire includes an upper end and a lower end. A portion of the magnetostrictive wire is operable to be received in the groove in the inner surface of the piezoelectric crystal.

[0006] In an exemplary embodiment, the sensor assembly for a magnetostrictive transmitter comprises a holder, a pair of substrates, a pair of piezoelectric crystals, and a magnetostrictive wire. The holder is formed from a non-conductive material. The holder includes an inner surface and an outer surface. The holder further includes an upper surface and a lower surface. Each substrate is formed from a non-conductive material. Each substrate includes an inner surface and an outer surface. Each substrate further includes an upper surface and a lower surface. Each substrate is operable to be received in the holder with the outer surface of each substrate opposing the inner surface of the holder and with the inner surface of one substrate opposing the inner surface of the other substrate. Each piezoelectric crystal includes an inner surface and an outer surface. Each piezoelectric crystal further includes an upper surface and a lower surface. Each piezoelectric crystal further includes a groove extending in the inner surface from the upper surface through the lower surface. Each piezoelectric crystal is operable to be mounted to one substrate with the outer surface of each piezoelectric crystal opposing the inner surface of one substrate and with the inner surface of one piezoelectric crystal opposing the inner surface of the other piezoelectric crystal. The magnetostrictive wire includes an upper end and a lower end. A portion of the magnetostrictive wire is operable to be received in the groove in the inner surface of each piezoelectric crystal.

[0007] In an exemplary embodiment, the sensor assembly for a magnetostrictive transmitter comprises a holder, a substrate, a piezoelectric crystal, and a magnetostrictive wire. The holder is formed from a non-conductive material. The holder includes an inner surface and an outer surface. The holder further includes an upper surface and a lower surface. The substrate is formed from a non-conductive material. The substrate includes an inner surface and an outer surface. The substrate further includes an upper surface and a lower surface. The substrate is operable to be received in the holder with the outer surface of the substrate opposing the inner surface of the holder. The piezoelectric crystal includes an inner surface and an outer surface. The piezoelectric crystal further includes an upper surface and a lower surface. The piezoelectric crystal further includes a groove extending in the inner surface from the upper surface through the lower surface. The piezoelectric crystal is operable to be mounted to the substrate with the outer surface of the piezoelectric crystal opposing the inner surface of the substrate. The magnetostrictive wire includes an upper end and a lower end. A portion of the magnetostrictive wire is operable to be received in the groove in the inner surface of the piezoelectric crystal. The portion of the magnetostrictive wire is in contact with the groove in the inner surface of the piezoelectric crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figures la-lc are views of a magnetostrictive transmitter according to an exemplary embodiment of the present invention, including an electronics housing and a sensor housing - Figure la is a perspective view, Figure lb is a partial cross-sectional perspective view taken along the line lb-lb in Figure la, including a sensor assembly in the sensor housing, and Figure lc is a detailed view of the section lc in Figure lb, including components of the sensor assembly in the sensor housing;

[0009] Figure 2 is a partial cross-sectional view of the sensor assembly in the sensor housing of the magnetostrictive transmitter of Figures la-lc;

[0010] Figures 3a-3c are views of the sensor assembly of the magnetostrictive transmitter of Figures la-lc - Figure 3a is a partial front elevational view, Figure 3b is a cross-sectional view taken along the line 3b-3b in Figure 3a, and Figure 3c is a detailed view of the section 3c in Figure 3b;

[0011] Figures 4a-4c are views of components of the sensor assembly of the magnetostrictive transmitter of Figures la-lc, including a holder, a substrate, a conductive strip, a conductive adhesive, a piezoelectric crystal, and a conductive plating - Figure 4a is a front elevational view, Figure 4b is a cross-sectional view taken along the line 4b-4b in Figure 4a, and Figure 4c is a partially exploded perspective view;

[0012] Figures 5a-5b are views of components of the sensor assembly of the magnetostrictive transmitter of Figures la-lc, including the substrate, the conductive strip, the conductive adhesive, the piezoelectric crystal, and the conductive plating - Figure 5a is a perspective view, and Figure 5b is an exploded perspective view;

[0013] Figures 6a-6c are views of components of the sensor assembly of the magnetostrictive transmitter of Figures la-lc, including the piezoelectric crystal and the conductive plating - Figure 6a is a top plan view, Figure 6b is a cross-sectional view taken along the line 6b-6b in Figure 6a, and Figure 6c is an exploded perspective view; and [0014] Figures 7a-7b are views of the magnetostrictive transmitter of Figures la-lc installed in a process - Figure 7a is a perspective view of the magnetostrictive transmitter connected to a vessel, and Figure 7b is a perspective view of the magnetostrictive transmitter connected to a gage.

DETAILED DESCRIPTION

[0015] The present invention provides a magnetostrictive transmitter with a piezoelectric crystal including a groove for receiving a magnetostrictive wire. Magnetostrictive transmitters are used in connection with magnetic liquid level indication products to sense the level of liquid in vessels or gages.

[0016] An exemplary embodiment of a magnetostrictive transmitter 10 of the present invention is illustrated in Figures la- 7b. In the exemplary embodiment, the magnetostrictive transmitter 10 includes an electronics housing 12, an electronics module (not shown), a sensor housing 14, and a sensor assembly 16. The electronics module is housed in the electronics housing 12. The sensor assembly 16 is housed in the sensor housing 14. The sensor housing 14 is attached to the electronics housing 12. Most of these components of magnetostrictive transmitters are well-known in the art and will not be described in greater detail. Only the sensor assembly 16 will be described in greater detail.

[0017] An exemplary embodiment of the sensor assembly 16 is shown in detail in

Figures lb-6c. In an exemplary embodiment, the sensor assembly 16 includes a holder 18, a substrate 20, a piezoelectric crystal 22, a magnetostrictive wire 24, and a PCB 26. In the illustrated embodiment, the sensor assembly 16 includes a pair of holders 18, a pair of substrates 20, a pair of piezoelectric crystals 22, the magnetostrictive wire 24, and the PCB 26.

[0018] An exemplary embodiment of the holder 18 is shown in detail in Figures lb-lc, 2,

3a-3b, and 4a-4c. In an exemplary embodiment, the holder 18 is formed from a non-conductive material. In an exemplary embodiment, the holder 18 includes an inner surface 28 and an outer surface 30. In an exemplary embodiment, the inner surface 28 of the holder 18 is generally planar, and the outer surface 30 of the holder 18 is generally curved. In an exemplary embodiment, the holder 18 further includes an upper surface 32 and a lower surface 34. In the illustrated embodiment, the holder 18 is generally half cylinder shaped. In the illustrated embodiment, the holder 18 further includes a recess 36 extending in the inner surface 28. In the illustrated embodiment, the recess 36 is generally rectangular prism shaped. In an exemplary embodiment, the non-conductive material of the holder 18 is polyetheretherketone (PEEK). However, one of ordinary skill in the art will appreciate that other non-conductive materials could be used, such as other plastics and ceramics. Additionally, in the illustrated embodiment, the sensor assembly 16 includes two holders 18. However, one of ordinary skill in the art will appreciate that the sensor assembly 16 could include more or less than two holders 18 so long as the holder(s) 18 are operable to receive the substrate(s) 20 as described in greater detail below. [0019] An exemplary embodiment of the substrate 20 is shown in detail in Figures lb-lc,

3a-3c, 4b-4c, and 5a-5b. In an exemplary embodiment, the substrate 20 is formed from a non-conductive material. In an exemplary embodiment, the substrate 20 includes an inner surface 38 and an outer surface 40. In an exemplary embodiment, the inner surface 38 of the substrate 20 is generally planar, and the outer surface 40 of the substrate 20 is generally planar. In an exemplary embodiment, the substrate 20 further includes an upper surface 42 and a lower surface 44. In an exemplary embodiment, the substrate 20 further includes a first side surface 46 and a second side surface 48. In the illustrated embodiment, the substrate 20 is generally rectangular prism shaped. In an exemplary embodiment, the substrate 20 is operable to be received in the holder 18 with the outer surface 40 of the substrate 20 opposing the inner surface 28 of the holder 18. In the illustrated embodiment, each substrate 20 is operable to be received in one holder 18 with the outer surface 40 of the substrate 20 opposing the inner surface 28 of the holder 18 and with the inner surface 38 of one substrate 20 opposing the inner surface 38 of the other substrate 20. In the illustrated embodiment, the substrate 20 is operable to be received in the recess 36 in the holder 18 with the outer surface 40 of the substrate 20 opposing the inner surface 28 of the holder 18. In an exemplary embodiment, the substrate 20 has a height h _s , a width ws, and a depth d _s (see Figure 5b). In an exemplary embodiment, the non-conductive material of the substrate 20 is a ceramic. However, one of ordinary skill in the art will appreciate that other non-conductive materials could be used, such as plastics and glass.

[0020] An exemplary embodiment of the piezoelectric crystal 22 is shown in detail in

Figures lb-lc, 3a-3c, 4b-4c, 5a-5b, and 6b-6c. In an exemplary embodiment, the piezoelectric crystal 22 is formed from a piezoelectric material. In an exemplary embodiment, the piezoelectric crystal 22 includes an inner surface 50 and an outer surface 52. In an exemplary embodiment, the inner surface 50 of the piezoelectric crystal 22 is generally planar, and the outer surface 52 of the piezoelectric crystal 22 is generally planar. In an exemplary embodiment, the piezoelectric crystal 22 further includes an upper surface 54 and a lower surface 56. In an exemplary embodiment, the piezoelectric crystal 22 further includes a first side surface 58 and a second side surface 60. In the illustrated embodiment, the piezoelectric crystal 22 is generally rectangular prism shaped. In an exemplary embodiment, the piezoelectric crystal 22 further includes a groove 62 extending in the inner surface 50 from the upper surface 54 through the lower surface 56. In the illustrated embodiment, the groove 62 extends generally equidistantly between the first side surface 58 and the second side surface 60. In the illustrated embodiment, the groove 62 has a generally rounded shape. In an exemplary embodiment, the groove 62 has a depth d (see Figure 3 c).

[0021] In an exemplary embodiment, the piezoelectric crystal 22 is operable to be mounted to the substrate 20 with the outer surface 52 of the piezoelectric crystal 22 opposing the inner surface 38 of the substrate 20. In the illustrated embodiment, each piezoelectric crystal 22 is operable to be mounted to one substrate 20 with the outer surface 52 of the piezoelectric crystal 22 opposing the inner surface 38 of the substrate 20 and with the inner surface 50 of one piezoelectric crystal 22 opposing the inner surface 50 of the other piezoelectric crystal 22.

[0022] In an exemplary embodiment, the inner surface 50 of one piezoelectric crystal 22 is generally parallel to the inner surface 50 of the other piezoelectric crystal 22. In an exemplary embodiment, the inner surface 50 of one piezoelectric crystal 22 does not contact the inner surface 50 of the other piezoelectric crystal 22. In an exemplary embodiment, the first side surface 58 and the second side surface 60 of one piezoelectric crystal 22 do not contact the first side surface 58 or the second side surface 60 of the other piezoelectric crystal 22. In an exemplary embodiment, no surface of one piezoelectric crystal 22 contacts any surface of the other piezoelectric crystal 22.

[0023] In an exemplary embodiment, the piezoelectric crystal has a height h _c , a width w _c , and a depth d _c (see Figure 5b). In an exemplary embodiment, the height h _s , the width w _s , and the depth d _s of the substrate 20 are greater than the height h _c , the width w _c , and the depth d _c of the piezoelectric crystal 22, respectively. In an exemplary embodiment, the height h _s , the width w _s , and the depth d _s of the substrate 20 are substantially greater than the height h _c , the width w _c , and the depth d _c of the piezoelectric crystal 22, respectively. [0024] An exemplary embodiment of the magnetostrictive wire 24 is shown in detail in

Figure lb-lc, 2, and 3a-3c. In an exemplary embodiment, the magnetostrictive wire 24 is formed from a magnetostrictive material. In an exemplary embodiment, the magnetostrictive wire 24 includes an upper end 64 and a lower end 66. In an exemplary embodiment, the upper end 64 of the magnetostrictive wire 24 is operable to be connected to another component of the sensor assembly 16 (as will be described in greater detail below). In an exemplary embodiment, the lower end 66 of the magnetostrictive wire 24 is operable to extend in the sensor housing 14. In an exemplary embodiment, the magnetostrictive wire 24 has a diameter d _w (see Figure 3c). In an exemplary embodiment, the depth d of the groove 62 in the inner surface 50 of the piezoelectric crystal 22 is less than half of the diameter d _w of the magnetostrictive wire 24.

[0025] In an exemplary embodiment, a portion of the magnetostrictive wire 24 is operable to be received in the groove 62 in the inner surface 50 of the piezoelectric crystal 22. In an exemplary embodiment, a portion of the magnetostrictive wire 24 is operable to be in contact with at least a portion of the groove 62 in the inner surface 50 of the piezoelectric crystal 22. In the illustrated embodiment, a portion of the magnetostrictive wire 24 is operable to be in contact with the entire groove 62 in the inner surface 50 of the piezoelectric crystal 22. In an exemplary embodiment, a portion of the magnetostrictive wire 24 is operable to be compressed in the groove 62 in the inner surface 50 of the piezoelectric crystal 22.

[0026] An exemplary embodiment of the PCB 26 is shown in detail in Figures lb-lc, 2, and 3a. PCBs for magnetostrictive transmitters are well-known in the art and will not be described in detail.

[0027] In an exemplary embodiment, the sensor assembly 16 further includes a conductive adhesive 68. An exemplary embodiment of the conductive adhesive 68 is shown in detail in Figures 3b-3c, 4c, and 5a-5b. In an exemplary embodiment, the conductive adhesive 68 is operable to mount the piezoelectric crystal 22 to the substrate 20.

[0028] In an exemplary embodiment, the sensor assembly 16 further includes a conductive plating 70. An exemplary embodiment of the conductive plating 70 is shown in detail in Figures 4c, 5a-5b, and 6a-6c. The conductive plating 70 is shown in other Figures (i.e., Figures lb-lc, 3b-3c, and 4b). However, due to a thickness of the conductive plating 70 and a scale of the Figures, the conductive plating 70 is not visible in these Figures. In Figure 6b, the thickness of the conductive plating 70 is exaggerated for illustration purposes. In an exemplary embodiment, the conductive plating 70 is formed from a metal. In an exemplary embodiment, the conductive plating 70 is operable to extend on at least a portion of the inner surface 50 of the piezoelectric crystal 22. In the illustrated embodiment, the conductive plating 70 is operable to extend on the entire inner surface 50 of the piezoelectric crystal 22. In an exemplary embodiment, the metal of the conductive plating 70 is gold. However, one of ordinary skill in the art will appreciate that other conductive metals could be used, such as nickel. Additionally, one of ordinary skill in the art will appreciate that the sensor assembly 16 may not include any conductive plating 70.

[0029] In an exemplary embodiment, the sensor assembly 16 further includes a conductive strip 72. An exemplary embodiment of the conductive strip 72 is shown in detail in Figures 4b-4c and 5a-5b. In an exemplary embodiment, the conductive strip 72 is formed from a metal. One of ordinary skill in the art will appreciate that the conductive strip 72 can be formed from any conductive metal. In an exemplary embodiment, the conductive strip 72 is operable to extend on at least a portion of the inner surface 38 of the substrate 20 and on at least a portion of the upper surface 42 of the substrate 20. In an exemplary embodiment, the conductive strip 72 is operable to extend on at least a portion of the inner surface 38 of the substrate 20, on at least a portion of the upper surface 42 of the substrate 20, and on at least a portion of the lower surface 44 of the substrate 20.

[0030] In an exemplary embodiment, the conductive strip 72 is operable to extend on at least a portion of the inner surface 38 of the substrate 20 between the inner surface 38 of the substrate 20 and the outer surface 52 of the piezoelectric crystal 22. In an exemplary embodiment, the conductive strip 72 is operable to extend on the inner surface 38 of the substrate 20 from the upper surface 42 of the substrate 20 to at least a portion of the inner surface 38 of the substrate 20 that opposes the outer surface 52 of the piezoelectric crystal 22. In the illustrated embodiment, the conductive strip 72 is operable to extend on the inner surface 38 of the substrate 20 from the upper surface 42 of the substrate 20 through at least a portion of the inner surface 38 of the substrate 20 that opposes the outer surface 52 of the piezoelectric crystal 22 to the lower surface 44 of the substrate 20.

[0031] In an exemplary embodiment, the conductive strip 72 is operable to extend on the upper surface 42 of the substrate 20 from the conductive strip 72 on the inner surface 38 of the substrate 20 to one of the first side surface 46 and the second side surface 48 of the substrate 20. In an exemplary embodiment, the conductive strip 72 is operable to extend on the lower surface 44 of the substrate 20 from the conductive strip 72 on the inner surface 38 of the substrate 20 to one of the first side surface 46 and the second side surface 48 of the substrate 20.

[0032] In an exemplary embodiment, the sensor assembly 16 further includes a connector

74. An exemplary embodiment of the connector 74 is shown in detail in Figures lb-lc, 2, and 3a. In an exemplary embodiment, the connector 74 is operable to connect the magnetostrictive wire 24 to another component of the sensor assembly 16. In the illustrated embodiment, the connector 74 is operable to connect the magnetostrictive wire 24 to the PCB 26. In the illustrated embodiment, the connector 74 is a binding post. However, one of ordinary skill in the art will appreciate that the magnetostrictive wire 24 could be connected to the sensor assembly 16 using other mechanisms and could be connected to other components of the sensor assembly 16. In an exemplary embodiment, the magnetostrictive wire 24 is connected to another component of the sensor assembly 16 at or above the piezoelectric crystal 22.

[0033] In an exemplary embodiment, the sensor assembly 16 further includes an insulator

76. An exemplary embodiment of the insulator 76 is shown in detail in Figures lb-lc, 2, and 3a. In an exemplary embodiment, the insulator 76 is formed from a non-conductive material. In an exemplary embodiment, the insulator 76 includes an upper end 78 and a lower end 80. In an exemplary embodiment, the insulator 76 includes a longitudinal opening 82 extending from the upper end 78 through the lower end 80. In the illustrated embodiment, the insulator 76 is generally cylindrical shaped. In an exemplary embodiment, the insulator 76 is operable to receive a portion of the magnetostrictive wire 24 in the longitudinal opening 82. In the illustrated embodiment, the lower end 80 of the insulator 76 is enclosed with a nut 84, such as a barrel nut.

[0034] The sensor assembly 16 can be assembled. In an exemplary embodiment, once assembled, some components of the sensor assembly 16 are secured using fasteners. In an exemplary embodiment, the fasteners are bolts 86, nuts 88, and washers 90. However, one of ordinary skill in the art will appreciate that other fasteners could be used. The assembly of sensor assemblies in magnetostrictive transmitters is well-known in the art and will not be described in greater detail

[0035] The magnetostrictive transmitter 10 can be installed in a process. In an exemplary embodiment, the magnetostrictive transmitter 10 is connected to a vessel, such as a drum or a tank. An exemplary embodiment of the magnetostrictive transmitter 10 connected to a vessel V is shown in detail in Figure 7a. In an exemplary embodiment, the vessel V includes a vessel float VF with magnets inside the vessel V. In another exemplary embodiment, the magnetostrictive transmitter 10 is connected to a gage, such as a liquid level gage. An exemplary embodiment of the magnetostrictive transmitter 10 connected to a gage G is shown in detail in Figure 7b. In an exemplary embodiment, the gage G includes a gage float GF with magnets inside the gage G. The installation of magnetostrictive transmitters in vessels and gages is well-known in the art and will not be described in greater detail.

[0036] During operation of the magnetostrictive transmitter 10, an electrical pulse is applied to the magnetostrictive wire 24. When the electrical pulse reaches the vessel float VF with the magnets inside the vessel V or the gage float GF with the magnets inside the gage G, a magnetic field generated by the electrical pulse will interact with a magnetic field generated by the magnets in the vessel float VF or the gage float GF and cause the magnetostrictive wire 24 to twist. The twist of the magnetostrictive wire 24 applies a mechanical stress to the piezoelectric crystals 22. The mechanical stress applied to the piezoelectric crystals 22 generates an electrical signal that is transmitted to the PCB 26 (through the conductive adhesives 68 and the conductive strips 72 on the substrates 20). Based on the time it takes from the electrical pulse being applied to the magnetostrictive wire 24 and the PCB 26 receiving the electrical signal, the level of the vessel float VF or the gage float GF and thus the level of the fluid in the vessel V or the gage G can be determined.

[0037] As used herein, when the magnetostrictive wire 24 is referred to as in contact with the groove 62 in the inner surface 50 of the piezoelectric crystal 22, the magnetostrictive wire 24 may be in physical contact with the groove 62 or with a plating or other coating in the groove 62, such as the conductive plating 70.

[0038] Additionally, as used herein, when a surface of one component opposes a surface of another component, the surfaces may be in physical contact with one another or there may be a gap between the surfaces. Moreover, the surfaces may have an additional component between them. For example, the outer surface 52 of the piezoelectric crystal 22 has been described as opposing the inner surface 38 of the substrate 20 even though the conductive adhesive 68 and the conductive strip 72 are between these surfaces.

[0039] One of ordinary skill in the art will now appreciate that the present invention provides a magnetostrictive transmitter with a piezoelectric crystal including a groove for receiving a magnetostrictive wire. Although the present invention has been shown and described with reference to particular embodiments, equivalent alterations and modifications will occur to those skilled in the art upon reading and understanding this specification. The present invention includes all such equivalent alterations and modifications and is limited only by the scope of the following claims in light of their full scope of equivalents.