Differential pressure sensor for dynamic high-pressure liquid system

Abstract

To provide a differential sensor and a liquid pressure system.SOLUTION: The present specification describes an example of a differential sensor designed to operate with a dynamic high-pressure liquid pressure system. The sensor includes an integrated sensor housing having sufficient durability for withstanding a very high liquid pressure and related stress. Further, the sensor uses a foil strain gage (not a piezoelectric strain gage, for example) to allow pressure measurement even under unique stress applied by the dynamic high-pressure liquid pressure system. Further, a sensor tube of the sensor serves to isolate the strain gage from a part of warp / bending stress which a main body of the sensor may receive due to the very high liquid pressure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 540,198, filed September 25, 2023, entitled “Differential Pressure Sensors for Dynamic, High Pressure, Hydraulic Systems,” the contents of which are incorporated herein by reference in their entirety.

[0002] This disclosure relates generally to differential pressure sensors, and more particularly to differential pressure sensors for dynamic high pressure hydraulic systems. [Background technology]

[0003] A pressure sensor measures the pressure of a fluid (e.g., air, gas, liquid, etc.). A differential pressure sensor measures the difference between two fluid pressures. Such sensors can be used to measure fluid pressure in hydraulic systems.

[0004] By comparing such a system with the present disclosure described in the remainder of this application with reference to the drawings, the limitations and disadvantages of the conventional and traditional approaches will become apparent to one skilled in the art. Summary of the Invention

[0005] The present disclosure relates to a differential pressure sensor for a dynamic high pressure hydraulic system substantially as illustrated and / or described in connection with at least one of the drawings and more fully as recited in the claims.

[0006] These and other advantages, aspects, and novel features of the present disclosure, as well as details of illustrated examples of the disclosure, will become more fully understood from the following description and drawings. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an example hydraulic system according to aspects of the present disclosure.

[0008] [Diagram 2] FIG. 2 is a perspective view of an example differential pressure sensor that may be used in the example hydraulic system of FIG. 1 according to an embodiment of the present disclosure.

[0009] [Diagram 3] FIG. 3 is a perspective view of a sensor cover of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure.

[0010] [Figure 4a] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4b] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4c] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4d] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4e] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4f] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4g] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4h] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 4i] 3A-3D are various views of a sensor housing of the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure.

[0011] [Figure 5a] 3A-3D are various views illustrating an exemplary first alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 5b]3A-3D are various views illustrating an exemplary first alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 5c] 3A-3D are various views illustrating an exemplary first alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 5d] 3A-3D are various views illustrating an exemplary first alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure.

[0012] [Figure 6a] 3A-3D are various views illustrating an exemplary second alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 6b] 3A-3D are various views illustrating an exemplary second alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 6c] 3A-3D are various views illustrating an exemplary second alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure.

[0013] [Figure 7a] 3A-3D are various views illustrating an exemplary third alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 7b] 3A-3D are various views illustrating an exemplary third alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 7c] 3A-3D are various views illustrating an exemplary third alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure.

[0014] [Figure 8a] 3A-3C are various views illustrating an exemplary fourth alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 8b]3A-3C are various views illustrating an exemplary fourth alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure. [Figure 8c] 3A-3C are various views illustrating an exemplary fourth alternative sensor housing that can be used with the differential pressure sensor of FIG. 2 in accordance with an embodiment of the present disclosure.

[0015] [Figure 9a] FIG. 3 illustrates an example sensor circuit that can be used in the differential pressure sensor of FIG. 2, according to an embodiment of the disclosure. [Figure 9b] FIG. 3 illustrates an example sensor circuit that can be used in the differential pressure sensor of FIG. 2, according to an embodiment of the disclosure.

[0016] [Figure 10] FIG. 3 is a perspective view of an example adapter that can be used with the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure.

[0017] [Figure 11a] 11A-11F show various views of the adapter of FIG. 10 attached to the sensor housing of FIGS. 4a-4f, according to an embodiment of the present disclosure. [Figure 11b] 11A-11F show various views of the adapter of FIG. 10 attached to the sensor housing of FIGS. 4a-4f, according to an embodiment of the present disclosure. [Figure 11c] 11A-11F show various views of the adapter of FIG. 10 attached to the sensor housing of FIGS. 4a-4f, according to an embodiment of the present disclosure. [Figure 11d] 11A-11F show various views of the adapter of FIG. 10 attached to the sensor housing of FIGS. 4a-4f, according to an embodiment of the present disclosure. [Figure 11e] 11A-11F show various views of the adapter of FIG. 10 attached to the sensor housing of FIGS. 4a-4f, according to an embodiment of the present disclosure.

[0018] [Figure 12] FIG. 11 is a perspective view of the differential pressure sensor of FIG. 2 attached to the sensor cover of FIG. 10 according to an embodiment of the present disclosure.

[0019] [Figure 13a] 4 is a cross-sectional view of a fifth alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure. [Figure 13b] 4 is a cross-sectional view of a fifth alternative sensor housing that can be used in the differential pressure sensor of FIG. 2 according to an embodiment of the present disclosure.

[0020] [Figure 14] 2 illustrates an example of an alternative differential pressure sensor and an alternative adapter that can be used in the example hydraulic system of FIG. 1 according to an aspect of the present disclosure.

[0021] [Figure 15] 15 illustrates an example of an alternative cover for the alternative differential pressure sensor of FIG. 14 according to an embodiment of the present disclosure.

[0022] [Figure 16a] 15A-15C are various views of the alternative adapter shown in FIG. 14 according to an embodiment of the present disclosure. [Figure 16b] 15A-15C are various views of the alternative adapter shown in FIG. 14 according to an embodiment of the present disclosure. [Figure 16c] 15A-15C are various views of the alternative adapter shown in FIG. 14 according to an embodiment of the present disclosure. [Figure 16d] 15A-15C are various views of the alternative adapter shown in FIG. 14 according to an embodiment of the present disclosure.

[0023] [Figure 17a] 15A-15C are various views illustrating an example sixth alternative sensor housing that can be used with the example alternative differential pressure sensor of FIG. 14 in accordance with an embodiment of the present disclosure. [Figure 17b] 15A-15C are various views illustrating an example sixth alternative sensor housing that can be used with the example alternative differential pressure sensor of FIG. 14 in accordance with an embodiment of the present disclosure. [Figure 17c]15A-15C are various views illustrating an example sixth alternative sensor housing that can be used with the example alternative differential pressure sensor of FIG. 14 in accordance with an embodiment of the present disclosure. [Figure 17d] 15A-15C are various views illustrating an example sixth alternative sensor housing that can be used with the example alternative differential pressure sensor of FIG. 14 in accordance with an embodiment of the present disclosure.

[0024] [Figure 18] FIG. 14A illustrates an example alternative sensor circuit that can be used with the example alternative differential pressure sensor of FIGS. 14a and 14b, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The figures are not necessarily to scale. Where appropriate, the same or similar reference numbers are used in the figures to refer to similar or identical components. For example, reference numbers utilizing letters (e.g., diaphragm 424a, diaphragm 424b) refer to the same reference number without the letter (e.g., diaphragm 424).

[0026] Some examples of the present disclosure relate to differential pressure sensors for use in dynamic, high pressure hydraulic systems. Dynamic, high pressure hydraulic systems can generate significant heat and pressure during normal operation, and at certain times can experience even higher pressure spikes. This heat and pressure can place significant stresses and / or fatigue on components of the hydraulic system, which can lead to failure of the components if they are not properly designed to withstand these stresses.

[0027] The differential pressure sensors disclosed herein are designed to withstand, among other things, the high heat, pressure, stress, and / or fatigue of dynamic, high pressure hydraulic systems. For example, the disclosed differential pressure sensors have an integral metal sensor housing that is durable enough to withstand very high fluid pressures and associated stresses. As another example, the disclosed differential pressure sensors use foil strain gauges that can withstand very high stresses, rather than piezoelectric elements, which may be more fragile, for example. Additionally, the disclosed differential pressure sensors include a sensor tube that helps isolate the diaphragm and strain gauge from some of the warping / bending stresses that the body of the sensor may experience due to very high fluid pressures.

[0028] Some examples of the present disclosure include a sensor housing with a first input port and a second input port; a first sensor tube connected to the sensor housing at a first tube housing end, the first sensor tube extending from the first tube housing end to a first conduit end isolated from the sensor housing; a second sensor tube connected to the sensor housing at a second tube housing end, the second sensor tube extending from the second tube housing end to a second conduit end isolated from the sensor housing; a first fluid conduit extending from the first input port through the sensor housing and the first sensor tube to the first conduit end, the first sensor tube configured to undergo a first deflection in response to a first fluid pressure in the first fluid conduit; and a second fluid conduit extending through a second sensor tube to a second conduit end, the second sensor tube configured to undergo a second deflection in response to a second fluid pressure in the second fluid conduit; a first circuit element coupled to the first sensor tube, the first circuit element having a first electrical characteristic determined by the first deflection of the first sensor tube; a second circuit element coupled to the second sensor tube, the second circuit element having a second electrical characteristic determined by the second deflection of the second sensor tube; and a sensing circuit electrically connected to the first circuit element and the second circuit element, the sensing circuit configured to determine a pressure difference between the first fluid pressure in the first fluid conduit and the second fluid pressure in the second fluid conduit based on the first electrical characteristic of the first circuit element and the second electrical characteristic of the second circuit element.

[0029] In some examples, the sensor housing further comprises a first housing end and a second housing end opposite the first housing end, the first housing end comprising a first input port and a second input port, and the second housing connects to the first or second sensor tube at the first or second tube housing end. In some examples, the first or second sensor tube is recessed within the sensor housing such that the sensor housing surrounds the first or second sensor tube. In some examples, the sensor housing is constructed of a metallic material.

[0030] In some examples, the sensor housing further comprises a first groove surrounding a first portion of the first sensor tube such that the first portion of the first sensor tube is isolated from the sensor housing and a second groove surrounding a second portion of the second sensor tube such that the second portion of the second sensor tube is isolated from the sensor housing. In some examples, the first circuit element comprises a first resistor, the second circuit element comprises a second resistor, the first electrical characteristic comprises a first resistance, and the second electrical characteristic comprises a second resistance. In some examples, the first circuit element comprises a first strain gauge, and the second circuit element comprises a second strain gauge.

[0031] In some examples, the first strain gauge and the second strain gauge are constructed of foil. In some examples, the sensor housing, the first sensor tube, and the second sensor tube comprise a single continuous piece of machined metal. In some examples, the first sensor tube comprises a first inner sensor tube wall in the first fluid conduit and a first outer sensor tube portion outside the first fluid conduit, the second sensor tube comprises a second inner sensor tube portion in the second fluid conduit and a second outer sensor tube portion outside the second fluid conduit, the first circuit element is bonded to the first outer sensor tube portion, and the second circuit element is bonded to the second outer sensor tube portion.

[0032] Some examples of the disclosure include a hydraulic device including a device housing enclosing a first fluid volume isolated from a second fluid volume; a differential pressure sensor, the sensor housing being constructed from a metallic material, the sensor housing including a first input port in fluid communication with the first fluid volume and a second input port in fluid communication with the second fluid volume; a first sensor tube connected to the sensor housing at a first tube housing end, the first sensor tube extending from the first tube housing end to a first conduit end isolated from the sensor housing; a second sensor tube connected to the sensor housing at a second tube housing end, the second sensor tube extending from the second tube housing end to a second conduit end isolated from the sensor housing; and a first fluid conduit extending from the first input port through the sensor housing and the first sensor tube to the first conduit end, the first sensor tube detecting a first fluid pressure in response to a first fluid pressure in the first fluid conduit. a first fluid conduit configured to undergo a first deflection; a second fluid conduit extending from a second input port through the sensor housing and the second sensor tube to a second conduit end, the second sensor tube configured to undergo a second deflection in response to a second fluid pressure in the second fluid conduit; a first circuit element coupled to the first sensor tube, the first circuit element having a first electrical characteristic determined by the first deflection of the first sensor tube; and a second sensor. the second circuit element bonded to the tube, the second circuit element having a second electrical characteristic determined by a second deflection of the second sensor tube; and a sensing circuit electrically connected to the first circuit element and the second circuit element, the sensing circuit configured to determine a pressure difference between a fluid in a first fluid volume of the hydraulic device and a fluid in a second fluid volume of the hydraulic device based on the first electrical characteristic of the first circuit element and the second electrical characteristic of the second circuit element.

[0033] In some examples, the sensor housing further comprises a first housing end and a second housing end opposite the first housing end, the first housing end comprising a first input port and a second input port, and the second housing connects to the first or second sensor tube at the first or second tube housing end. In some examples, the first or second sensor tube is recessed within the sensor housing such that the sensor housing surrounds the first or second sensor tube. In some examples, the sensor housing is constructed of a metallic material.

[0034] In some examples, the sensor housing further comprises a first groove surrounding a first portion of the first sensor tube such that the first portion of the first sensor tube is isolated from the sensor housing and a second groove surrounding a second portion of the second sensor tube such that the second portion of the second sensor tube is isolated from the sensor housing. In some examples, the first circuit element comprises a first resistor, the second circuit element comprises a second resistor, the first electrical characteristic comprises a first resistance, and the second electrical characteristic comprises a second resistance. In some examples, the first circuit element comprises a first strain gauge, and the second circuit element comprises a second strain gauge.

[0035] In some examples, the first strain gauge and the second strain gauge are constructed of foil. In some examples, the sensor housing, the first sensor tube, and the second sensor tube comprise a single continuous piece of machined metal. In some examples, the first sensor tube comprises a first inner sensor tube portion within the first fluid conduit and a first outer sensor tube portion outside the first fluid conduit, the second sensor tube comprises a second inner sensor tube portion within the second fluid conduit and a second outer sensor tube portion outside the second fluid conduit, the first circuit element is bonded to the first outer sensor tube portion, and the second circuit element is bonded to the second outer sensor tube portion.

[0036] Figure 1 illustrates an example of a hydraulic system 100. In the example of Figure 1, the hydraulic system 100 includes a hydraulic actuator 102 and an actuating fluid supply 104 in fluid communication with the hydraulic actuator 102. In some examples, the actuating fluid supply 104 may include one or more hydraulic pumps and / or actuating fluid tanks configured to circulate actuating fluid through the hydraulic actuator 102 of the hydraulic system 100.

[0037] 1, the hydraulic actuator 102 includes an actuator housing 106. A hydraulic piston 108 is positioned within the actuator housing 106. A piston seal 110 of the hydraulic piston 108 is enclosed within the actuator housing 106 at an end of the hydraulic piston 108.

[0038] As shown, the piston seal 108 divides the interior volume of the actuator housing 106 into two sections 112. Actuating fluid pressure within the interior volume of the actuator housing 106 acts on the piston seal 110, thereby causing the hydraulic piston 108 to move (e.g., back and forth). More specifically, a pressure differential on either side of the piston seal 110 (and / or a difference between the pressure in section 112a and the pressure in section 112b) may cause the hydraulic piston 108 to move.

[0039] Thus, for example, if the fluid pressure in the interior volume of the first section 112a of the actuator housing 106 is greater than or less than the fluid pressure in the second section 112b of the actuator housing 106, the difference in fluid pressure may induce movement of the piston 108. On the other hand, if the fluid pressure in the first section 112a is equal to the fluid pressure in the second section 112b, the piston 108 may remain stationary.

[0040] 1, the actuator housing 106 includes a fluid port 114 in fluid communication with the interior volume section 112 of the actuator housing 106. The fluid port 114 is then shown in fluid communication with a manifold 150 via a fluid line 118. The fluid line internal to the manifold 150 connects to a differential pressure sensor 200, which is thereby in fluid communication with the interior volume section 112 of the actuator housing 106.

[0041] The differential pressure sensor 200 is secured to the manifold 150 via manifold fasteners 250 (see, e.g., FIG. 2). In the example of FIG. 1, the differential pressure sensor 200 is electrically connected to the actuator controller 120 of the hydraulic actuator 102. In some examples, the differential pressure sensor 200 can output one or more electrical signals representative of the pressure difference across the interior volume sections 112 of the hydraulic actuator 102. In some examples, the actuator controller 120 can use the signal(s) from the differential pressure sensor 200 (and / or the pressure difference measured by the differential pressure sensor 200) to control the hydraulic actuator 102 (and / or other portions of the hydraulic system 100).

[0042] Although it may theoretically be possible to use two separate pressure sensors and connecting circuitry instead of differential pressure sensor 200, there are many advantages to using differential pressure sensor 200 rather than two separate pressure sensors. For example, differential pressure sensor 200 is generally smaller and more compact than two separate pressure sensors and connecting circuitry. Furthermore, differential pressure sensor 200 does not need to be as sensitive and / or responsive as a separate pressure sensor (e.g., because differential pressure sensor 200 measures only pressure differences and not actual pressures). Furthermore, many legacy (e.g., hydraulic) systems traditionally use multiple differential pressure sensors, and it is much simpler, more cost-effective, and / or more efficient to continue to use differential pressure sensor 200 with the system than to modify or retrofit the system to work with separate multiple pressure sensors.

[0043] 1 as including a hydraulic actuator 102, in some examples, the hydraulic system 100 may include one or more additional and / or alternative hydraulic devices. In some examples, the hydraulic system 100 may be part of a larger system that tests various structures and / or machines (e.g., buildings, bridges, airplanes, trains, automobiles, ships, turbines, oil rigs, etc.). For example, the hydraulic system 100 may be used to test the reliability, durability, flexibility, balance, strength, and / or other aspects of various structures and / or machines. In so doing, the hydraulic actuator 102 and / or differential pressure sensor 200 may be subjected to dynamic hydraulic pressures of up to 5000 pounds per square inch (psi) with possible pressure spikes of up to 15000 psi.

[0044] FIG. 2 illustrates an enlarged perspective view of an example differential pressure sensor 200. In the example of FIG. 2, the differential pressure sensor 200 includes a sensor cover 300 attached to the top of a sensor housing 400, thereby enclosing a sensing circuit 900 (discussed further below with respect to FIG. 9) between the sensor cover 300 and the sensor housing 400. As shown, the sensor cover 300 is attached to the sensor housing 400 using cover fasteners 202 inserted through aligned cover fastener holes 302 / 402 (see also, e.g., FIGS. 3 and 4a) in the sensor cover 300 and the sensor housing 400. Manifold fasteners 250 are shown extending through the sensor cover 300 and the sensor housing 400 to fasten the differential pressure sensor 200 to the manifold 150. The sensor cover 300 further includes manifold fastener channels 350 (eg, sealed from the inside of the sensor cover 300 ) through which the manifold fasteners 250 can be inserted into the sensor housing 400 and / or the manifold 150 .

[0045] In the examples of FIGS. 2-4, the sensor cover 300 further includes a sensor input / output (I / O) connector 304. Although obscured due to the perspective view, the sensor I / O connector 304 includes several conductive pins through which the sensor I / O connector 304 can be electrically connected to other devices (e.g., the actuator controller 120). In some examples, the differential pressure sensor 200 can output a signal representative of the measured differential pressure through the sense I / O connector 304 (e.g., its pins). In some examples, the differential pressure sensor 200 can receive power (e.g., to power its circuitry) through the sense I / O connector 304 (e.g., its pins).

[0046] 4a-4f show example views of the sensor housing 400 of the differential pressure sensor 200 with the sensor cover 300 and manifold fastener 250 removed. As shown, the sensor housing 400 includes a cubical body 404 having a front wall 406, a rear wall 408, a top wall 410, a bottom wall 412, and a side wall 414. A manifold fastener conduit 450 extends through the sensor housing 400 from the top wall 410 to the bottom wall 412 (see, e.g., FIGS. 11c and 11e).

[0047] In the example of Figures 4c and 4e-f, the bottom wall 412 of the sensor housing 400 has two circular input ports 416. In some examples, one or more of the input ports 416 may alternatively or additionally be positioned in, on, and / or at the front wall 406, rear wall 408, and / or side wall 414. As shown, the input ports 416 lead to fluid conduits 418 that extend through the sensor housing 400 from the bottom wall 412 to the top wall 410. As shown, each fluid conduit 418 is approximately cylindrical (e.g., all points on the wall of the fluid conduit 418 are equidistant from the central axis of the fluid conduit 418 along a plane approximately perpendicular to the central axis within 5% of the mean, mode, or average distance from the central axis along the perpendicular plane).

[0048] In some examples, each input port 416 of the sensor housing 400 can be connected to a different fluid line 118 in the manifold 150 when the differential pressure sensor 200 is used in the hydraulic system 100 shown in FIG. 1. Accordingly, each input port 416 and / or fluid conduit 418 of the sensor housing 400 can be in fluid communication with a different interior volume section 112 of the actuator housing 106 when the differential pressure sensor 200 is used in the hydraulic system 100 shown in FIG.

[0049] 4c and 4e, each input port 416 includes an annular groove into which an O-ring 420 is fitted. In some examples, the O-ring 420 can serve to seal the input ports 416 and / or the fluid conduits 418 when connected to the manifold 150. In examples where one or more of the input ports 416 can alternatively or additionally be positioned in, on, and / or at the front wall 406, the rear wall 408, and / or the side wall 414, a threaded connection may alternatively or additionally be used. In examples where two input ports 416 lead to and / or connect to the same fluid conduit 418, a port seal can be used to seal one of the input ports 416 when not in use.

[0050] 4e and 4f, the fluid conduits 418 extend through the sensor housing 400 into two generally cylindrical sensor tubes 422 that are connected to the top wall 410 of the sensor housing 400. In some examples, the cylindrical shape of the sensor tubes 422 may be more durable than a polygonal shape because it reduces the number of edges and / or corners that may burst under pressure. Additionally, polygonal shapes (and / or square holes) may be more difficult and / or expensive to machine.

[0051] As shown, each sensor tube 422 extends approximately perpendicular (e.g., within 5 degrees of 90 degrees) to the top wall 410, and the two sensor tubes 422 extend approximately parallel (e.g., within 5 degrees of 0 / 180 degrees) to one another. The height (e.g., in the y-axis direction) of each sensor tube 422 (e.g., beginning from the top wall 410) is shown to be approximately one-third (e.g., within 5% of) the height (e.g., in the y-axis direction) of the body 404 of the sensor housing 400. Each sensor tube 422 (and / or fluid conduit 418) is shown to terminate in a sensor diaphragm 424.

[0052] In the examples of Figures 4a-4f, each sensor diaphragm 424 closes an end of a sensor tube 422 (and / or fluid conduit 418). As shown, each sensor diaphragm 424 is approximately circular (e.g., where all points on the circumference of the diaphragm 424 are equidistant from a center point within 5% of the mean, mode, or average distance). Each sensor diaphragm 424 is further illustrated as having a width (e.g., in the y-direction) that is approximately the same thickness as the width of the sidewall of the sensor tube 422 to which the diaphragm is attached. In some examples, the relatively thin width of the diaphragm 424 can cause fluid pressure of the working fluid in the fluid conduit 418 to force the diaphragm 424 (e.g., its central portion) to flex, expand, deform, and / or bend outward (e.g., in the y-direction).

[0053] 4a and 4d, the differential pressure sensor 200 further includes strain gauges 426 attached, fastened, bonded, and / or otherwise bonded to the diaphragm 424. As shown in FIG. 4d, four strain gauges 426 are shown bonded to each diaphragm 424. Each strain gauge 426 is shown bonded to an outer surface of the diaphragm 424 that is outside of the fluid conduit 418 and / or sensor tube 422 and to an opposite inner surface of the diaphragm 424 that is positioned within the fluid conduit 418 and / or sensor tube 422. In some examples, when so positioned on diaphragm 434, inner / center strain gauges 426a1, 426a2, 426b1, and 426b2 may respond to and / or measure circumferential and / or hoop strains, while outer strain gauges 426a3, 426a4, 426b3, and 426b4 may respond to and / or measure radial strains. In some examples, differential pressure sensor 200 may primarily use strain gauges 426a1, 426a2, 426b1, and 426b2 bonded to a central portion of diaphragm 400 for pressure detection.

[0054] In some examples, the strain gauge 426 may additionally or alternatively be bonded to the outer surface of the sensor tube 422 (e.g., near the diaphragm(s) 424). This situation is illustrated, for example, by dashed strain gauges 426c and 426d on the outer surface of the sensor tube 422 in FIG. 4a. In some examples, if the strain gauge 426 is positioned on the outer surface of the sensor tube 422, the differential pressure sensor 400 may rely more heavily on the outer (rather than inner) strain gauge 426. In some examples, if the strain gauge 426 is positioned on the outer surface of the sensor tube 422, the strain gauges 426c and 426d may respond to hoop stresses on the sensor tube 422.

[0055] In some examples, each strain gauge 426 may include a foil material whose electrical resistance (and / or impedance) changes with an applied force. For example, the resistance of the strain gauge 426 may increase as the strain gauge 426 stretches. Because each strain gauge 426 is bonded to the diaphragm 424, the strain gauge 426 will stretch as the diaphragm 424 stretches (and / or flexes, deforms, expands, etc.), which may occur, for example, in response to fluid pressure from the fluid in the fluid conduit 418. In particular, the strain gauges 426a1, 426a2, 426b1, and 426b2 bonded to a central portion of the diaphragm 400 will stretch as the diaphragm 424 stretches. In this configuration, the resistance (and / or impedance) of each strain gauge 426 is determined by the extent to which its diaphragm 424 stretches (and / or flexes, deforms, expands, etc.).

[0056] In some examples, foil strain gauges 426 are used in differential pressure sensor 200 because they are more resilient and / or can withstand higher stresses, as opposed to, for example, piezoelectric elements, which are more fragile and therefore more susceptible to failure under the high temperatures and / or stresses of hydraulic system 100. Strain gauges 426 are further bonded to an outer surface of diaphragm 424 such that strain gauges 426 are protected from direct contact with pressurized working fluid at high temperatures.

[0057] Along with a direct connection (e.g., no intervening oil or intermediate diaphragm) between the input port 416 and the diaphragm 424 to which the strain gauge 426 is bonded, it may also be advantageous to bond the strain gauge 426 to an outer surface of the diaphragm 424. For example, this configuration means that a mechanical tool can be inserted through the input port 416 and fluid conduit 418 to mechanically alter the width of the diaphragm 424, even after the strain gauge 426 is bonded to the diaphragm 424. In some examples, altering the width of the diaphragm 424 may cause the diaphragm 424 to be more likely to deflect (and / or expand, deform, etc.) in response to fluid pressure.

[0058] In some examples, it may be desirable for a particular diaphragm 424 to be more flexible (and / or expand, deform, etc.) in response to fluid pressure. For example, it may be desirable to have one diaphragm 424 be more sensitive and / or responsive than another diaphragm 424, such as in a hydraulic system where there is some pressure differential at steady state. In such examples, one diaphragm 424 may be thinner (and thus more sensitive / responsive and / or flexible) than the other diaphragm 424, such that the sensor 200 outputs a zero pressure differential (and / or a signal value representative thereof) when there is some pressure imbalance (e.g., a steady state pressure imbalance).

[0059] In some examples, the sensor tube 422 can be considered part of the sensor housing 400. In some examples, the body 404, the sensor tube 422, and the diaphragm 424 of the sensor housing 400 can include one integral, continuous, machined piece of material (e.g., steel and / or other metal) without welded connections. In some examples, this integral design can help the sensor 200 better withstand the high pressures and / or stresses of the hydraulic system 100, as opposed to a welded design that may be more susceptible to failure along weld seams under high pressures and / or stresses.

[0060] Although the one-piece design of the sensor housing 400 may prevent tearing, bursting, and / or breakage along the weld seams of the sensor housing 400, the body 404 of the sensor housing 400 may still be subject to bending and / or bulging stresses due to the high pressure of the actuating fluid. In particular, the pressurized actuating fluid may exert an upward (e.g., in the y direction) and / or an outward (e.g., in the x direction and / or z direction) force on the sensor housing 400 when within the fluid conduit 418 of the sensor housing 400. When the sensor housing 400 is subjected to the upward and outward forces, it may bend upwardly and / or bulge outwardly somewhat as it is fastened to the manifold 150.

[0061] In some examples, locating the diaphragm 424 and / or strain gauge 426 at the end of the sensor tube 422 that extends away from the body 404 of the sensor housing 400 can isolate the diaphragm 424 and / or strain gauge 426 from most of the effects of outward bulging experienced by the sensor housing 400. This can be important because such bulging of the sensor tube 422 near the diaphragm 424 can affect the strain gauge 426 (e.g., its resistance) in a manner that distorts the measurements and / or output of the sensor 200.

[0062] 5a-5c show an example of a first alternative sensor housing 500 that can be used with differential pressure sensor 200. First alternative sensor housing 500 is similar (and / or identical) to sensor housing 400 of FIGS. 4a-4f, except that first alternative sensor housing 500 does not have a sensor tube 422. Rather than diaphragm 424 being positioned at the end of sensor tube 422 (and / or fluid conduit 418) that extends beyond top wall 410, fluid conduit 418 extends only up to top wall 410 and diaphragm 424 forms part of and / or is substantially flush with top wall 410. As discussed above, the configuration of the first alternative sensor housing 500 may result in the sensor housing 400 bulging near the diaphragm 424, which may affect the strain gauge 426 (e.g., its resistance) in a manner that distorts the measurements and / or output of the sensor 200.

[0063] 4g and 5d show exaggerated examples of how the sensor housing 400 and the first alternative sensor housing 500 may be subjected to upward (e.g., in the y direction) and / or outward (e.g., in the x and / or z directions) bending fluid pressure stresses. As shown, the respective bodies 404 / 504 of the sensor housing 400 and the first alternative sensor housing 500 bend somewhat in the y direction such that each body 404 / 504 is slightly bowed. Because the diaphragm 424 is part of the body 504 of the first alternative sensor housing 500 of FIG. 5d, the diaphragm 424 may also bend in this manner, distorting the measurements of the associated strain gauge 426. In contrast, the use of the sensor tube 422 in the sensor housing 400 of FIG. 4g allows the diaphragm 424 to be isolated from the body 404, greatly reducing the bending stress experienced by the diaphragm 424.

[0064] 4h and 4i are top and perspective views of the sensor body 400. These views are simplified and semi-transparent to show additional exaggerated examples of the effects of upward (e.g., in the y direction) and / or outward (e.g., in the z direction) bulging fluid pressure stresses on the sensor housing 400. As shown, fluid pressure stresses on the body 404 can result in the fluid conduit 418 and / or the sensor tube 422 expanding into an oval, egg, and / or elliptical (rather than circular) shape where the sensor tube 422 connects to the top wall 410 of the body 404 of the sensor housing 400 (e.g., at the sensor tube-housing connection point 423). However, the use of the sensor tube 422 can extend the diaphragm 424 away from and / or isolate it from the body 404 of the sensor housing 400, significantly reducing the bending and / or bulging stresses experienced by the diaphragm 424 and allowing the diaphragm 424 to remain approximately circular. The configuration of one diaphragm 424 and one sensor tube-housing connection point 423 are shown roughly schematic in dotted lines in Figures 4h and 4i to illustrate this situation.

[0065] 6a-6c show an example of a second alternative sensor housing 600 that can be used with differential pressure sensor 200. The second alternative sensor housing 600 is similar to the first alternative sensor housing 500 of FIGS. 5a-5c in that the fluid conduit 418 extends only to the top wall 410 and the diaphragm 424 is approximately flush with the top wall 410. The second alternative sensor housing 600 is similar to the sensor housing 400 of FIGS. 4a-4f in that the second alternative sensor housing 600 includes a second alternative sensor tube 622.

[0066] 4a-g, the second alternative sensor tube 622 is separated from the second alternative body 604 of the second alternative sensor housing 600. As with the sensor tube 422 of Figures 4a-g, this separation and / or isolation of the second alternative sensor tube 622 can help isolate the diaphragm 424 and / or strain gauge 426 from most of the bending and / or bulging effects experienced by the second alternative body 604.

[0067] However, the separation of the second alternative sensor tube 622 from the second alternative body 604 is not by the second alternative sensor tube 622 extending above the top wall 410, but rather by a trepanned annular groove 630 that surrounds the second alternative sensor tube 622. In the example of Figures 6a-6c, the annular groove 630 is interposed between the second alternative body 604 and the second alternative sensor tube 622 such that the second alternative body 604 surrounds both the annular groove 630 and the second alternative sensor tube 622. In other respects, the second alternative sensor housing 600 may be similar (and / or identical) to the sensor housing 400 of Figures 4a-4g.

[0068] 7A-7c show an example of a third alternative sensor housing 700 that can be used with differential pressure sensor 200. As shown, the third alternative sensor housing 700 is similar (and / or identical) to the second alternative sensor housing 600. However, instead of being flush with the top wall 410 as in the second alternative sensor housing 600 of FIGS. 6a-6c, the third alternative sensor tube 722 extends above the top wall 410 of the third alternative sensor housing 700, similar to the sensor housing 400 of FIGS. 4a-4g. In this configuration, the annular groove 730 (and / or the third alternative sensor housing 700) surrounds only the portion of the third alternative sensor tube 722 that is below the top wall 410 of the third alternative sensor housing 700.

[0069] 8a-8c show an example of a fourth alternative sensor housing 800 that can be used with differential pressure sensor 200. As shown, fourth alternative sensor housing 800 is similar (and / or identical) to second alternative sensor housing 600 and / or third alternative sensor housing 700, except that fourth alternative sensor tube 822 is recessed below top wall 410 of third alternative sensor housing 700 (and / or within third alternative sensor housing 700). In this configuration, annular groove 830 (and / or fourth alternative sensor housing 800) surrounds the entirety of fourth alternative sensor tube 822, diaphragm 424, and some space above diaphragm 424 (e.g., in the direction of the positive y-axis).

[0070] In the example of Figures 4a-4f, the differential pressure sensor 200 includes a total of eight strain gauges 426, with four strain gauges 426 bonded to each of the two diaphragms 424. However, as discussed above, the differential pressure sensor 200 may primarily use strain gauges 426a1, 426a2, 426b1, and 426b2 bonded to a central portion of the diaphragm 400 for pressure sensing. Figure 9a shows four strain gauges 426a1, 426a2, 426b1, and 426b2 connected together in a sensing circuit 900a.

[0071] In some examples, the sensing circuit 900a is configured to generate an output signal 904 representative of a difference in resistance between the strain gauge 426a1 and / or the strain gauge 426a2 bonded to the first diaphragm 424a and the strain gauge 426b1 and / or the strain gauge 426b2 bonded to the second diaphragm 424b. Since the resistance of the central strain gauge 426 bonded to a particular diaphragm 242 should be approximately equal, the difference in resistance between the strain gauges 426 of the different diaphragms 424 can be the result of differences in the deflection (and / or strain, deformation, etc.) of the diaphragms 424. Also, since the deflection (and / or strain, deformation, etc.) of the diaphragms 424 is due to the fluid pressure in the fluid conduits 418, the output signal can represent a difference in the fluid pressure in the respective fluid conduits 418.

[0072] In the example of Figure 9a, the sensing circuit 900a is further shown as including terminals 434. In the examples of Figures 4a-4f, the terminals 434 are attached to the top wall 410 of the sensing housing. In the example of Figure 9a, the sensing circuit 900a is shown as possibly including two conventional resistors 430 and / or two abradable resistors 432. In the example of Figures 4a-4f, the conventional resistors 430 and the abradable resistors 432 are also shown attached to the top wall 410 of the sensor housing 400.

[0073] 5a-8c for simplicity, the conventional resistor 430, the grindable resistor 432, and / or the terminals 434 may similarly be attached to the top wall 410 of the first alternative sensor housing 500, the second alternative sensor housing 600, the third alternative sensor housing 700, and / or the fourth alternative sensor housing 800. Additionally, the strain gage 426 may be attached to the diaphragm 424 of the first alternative sensor housing 500, the second alternative sensor housing 600, the third alternative sensor housing 700, and / or the fourth alternative sensor housing 800.

[0074] 9a, the sensing circuit 900a is a modified Wheatstone bridge with the strain gauges 426 forming the primary resistive elements of the Wheatstone bridge. As shown, strain gauges 426a1 and 426b1 are wired together in series, strain gauges 426a2 and 426b2 are wired together in series, and the two series are wired in parallel with each other to a power input 902 (and / or power input pin) of the sensor I / O connector 304. In some examples, the power input 902 (and / or power input pin) of the sensor I / O connector 304 can be connected to a power source of the hydraulic system 100 (e.g., via the actuator controller 120).

[0075] 9a, terminal 434b and terminal 434d of sensing circuit 900a are connected to an output 904 (and / or an output signal pin) of sensor I / O connector 304. In some examples, when the voltage across terminal 434b and terminal 434d (and / or the current flowing from terminal 434b to terminal 434d) is zero, the output 904 of sensor I / O connector 304 is zero.

[0076] In some examples, the zero output 904 at the sensor I / O connector 304 may be a result of strain gauge 426a1 and / or strain gauge 426a2 having a resistance approximately equal to the resistance of strain gauge 426b1 and / or strain gauge 426b2. In some examples, strain gauge 426a1 and / or strain gauge 426a2 having a resistance approximately equal to the resistance of strain gauge 426b1 and / or strain gauge 426b2 may occur when the deflection of diaphragm 424a is approximately equal to the deflection of diaphragm 424b. In some examples, the deflection of diaphragm 424a is approximately equal to the deflection of diaphragm 424b when the fluid pressure in fluid conduit 418a is approximately the same as the fluid pressure in fluid conduit 418b. Thus, in some examples, a zero output 904 of the sensor I / O connector 304 may indicate that the fluid pressure in the fluid conduit 418a is approximately the same as the fluid pressure in the fluid conduit 418b.

[0077] In the example of FIG. 9a, conventional resistor 430 is drawn with dashed lines to show how it may be placed in series or parallel with strain gauge 426a1 (e.g., as a shunt resistor). In some examples, conventional resistor 430 may be placed in series and / or parallel with strain gauge 426a1 to balance the resistance in the two parallels of sensing circuit 900a. While shown as applied to sensing circuit 900a in series or parallel with strain gauge 426a1 for clarity, one skilled in the art will understand that conventional resistor 430 may alternatively be placed in series and / or parallel with strain gauge 426a2, strain gauge 426b1, or strain gauge 426b2.

[0078] For example, if the diaphragm 424a to which strain gauge 426a1 is attached is (e.g., by accident) machined to be less sensitive / responsive (and / or thicker) than the other diaphragms 424b, a conventional resistor 430 can be placed in series with strain gauge 426a to balance the sensing circuit 900. As another example, if the diaphragm 424b to which strain gauges 426b1 and 426b2 are attached is (e.g., by accident) machined to be more sensitive / responsive (and / or thinner) than the other diaphragms 424a, a conventional resistor 430 can be placed in parallel with strain gauges 426b1 and 426b2.

[0079] In the example of FIG. 9a, each grindable resistor 432 is depicted with dashed lines to show how it may be arranged in the sensing circuit 900 as needed. As shown, each grindable resistor 432 can be used in place of a terminal 434 (and / or includes a terminal 434 within itself). Each grindable resistor 432 essentially includes two resistors 432a and 432b positioned on either side of a terminal 434. In some examples, the resistance value of each resistor 432a / 432b of the grindable resistors 432 can be changed by grinding. In some examples, one of the grindable resistors 432 (e.g., replacing terminal 434c) can be used to balance a Wheatstone bridge, and the other grindable resistor 432 (e.g., replacing terminal 434d) can be used for temperature compensation. Although the grindable resistor is shown replacing terminals 434c and 434d, in some instances it may replace 434a and / or 434b instead.

[0080] While sensing circuit 900a in Figure 9a is shown as a bridge including four strain gauges 426a1, 426a2, 426b1, and 426b2, Figure 9b shows sensing circuit 900b including two bridges with all eight strain gauges 426. However, such a configuration may be more complex and / or require more power.

[0081] Although the sensing circuit 900 in FIGS. 9a and 9b is shown in a particular configuration, in some examples, the sensing circuit 900 may be configured differently. In some examples, the sensing circuit 900 may use different sensing elements (e.g., instead of and / or in addition to the strain gauge 426). For example, the differential pressure sensor 400 may include multiple sensors 299 that detect and / or measure the deflection of the diaphragm 424 (and / or the sensor tube 422) using different means (e.g., optical, ultrasonic, etc.). For example, FIG. 2 shows the sensor 299 connected to the sensing circuit 900 and enclosed between the sensor cover 300 and the sensor housing 400. In some examples, the sensor 299 may be connected to the sensor housing 400 or may be separate from the sensor housing 400. In some examples, the sensor 299 may instead be connected to the sensor cover 300. In some examples, the sensor 299 may instead be connected to the sensor cover 300. In some examples, the sensing circuit 900 may instead or additionally use the electrical signal and / or characteristics of the sensor 299 to determine the pressure differential.

[0082] 9a and 9b are shown as analog circuits, in some examples, the sensing circuit(s) 900 may be digital and / or include one or more digital elements (e.g., analog-to-digital converter(s)). In some examples, one or more of the strain gauges 426 may be connected to a processing chip, such as a digital signal processor, which may implement one or more functions of the sensing circuit(s) 900. In some examples, the sensing circuit(s) 900 may include one or more amplifiers to amplify the output of the sensing circuit(s) 900.

[0083] Fig. 10 shows an example of the adapter 1000 of the differential pressure sensor 200. Figs. 11a to 11e show the adapter 1000 attached to the sensor housing 400. Fig. 12 shows the adapter 1000 attached to the sensor housing 400 and the detection cover 300.

[0084] In the example of FIG. 10, the adapter 1000 includes manifold fastener channels 1050 configured to align with manifold fastener channels 350 of the sensor cover 300 and / or manifold fastener conduits 450 of the sensor housing 400. In some examples, the manifold fastener channels 1050 of the adapter 1000 are configured to receive manifold fasteners 250 to attach the cover 300 and / or the sensor housing 400 to the adapter 1000. In some examples, the cover 300 and / or the sensor housing 400 can be attached to the adapter 1000 via the manifold fasteners 250 in much the same way that the cover 300 and / or the sensor housing 400 are attached to the manifold 150. FIGS. 11c and 11e show manifold fasteners 250 attaching the sensor housing 400 to the adapter 1000 via the manifold fastener channels 1050.

[0085] 10, the adapter 1000 further includes an adapter fastener channel 1052. In some examples, the adapter fastener channel 1052 can be aligned with a complementary channel of the manifold 150. An adapter fastener 1054 can then be inserted through the adapter fastener channel 1052 and / or the complementary channel of the manifold 150 to attach the adapter 1000 to the manifold 150. FIG. 11d shows an example of an adapter fastener 1054 inserted through the adapter fastener channel 1052 of the adapter 1000.

[0086] In some examples, the adapter 1000 can be attached to the sensor cover 300, the sensor housing 400, and / or the manifold 150 to retrofit the differential pressure sensor 200 for use with an existing hydraulic system 100. For example, the differential pressure sensor 200 can be used as a substitute for a differential pressure sensor of a different design, and thus an existing hydraulic system 100 can be configured for a differential pressure sensor of a different design.

[0087] In the example of Figures 10 and 11d, the retrofit functionality of the adapter 1000 is shown via the adapter input port 1016 and adapter fluid conduit 1018 of the adapter 1000, which are shown as smaller than the input port 416 and fluid conduit 418 of the sensor housing 400. In some examples, the size of the adapter input port 1016 and adapter fluid conduit 1018 of the adapter 1000 can correspond to the size of the fluid lines of the manifold 150 of the existing hydraulic system 100 (and / or the ports / conduits of the sensor being replaced). Although shown as smaller by way of example in Figures 10 and 11d, in some examples, the adapter input port 1016 and / or adapter fluid conduit 1018 of the adapter 1000 may instead be larger than the input port 416 and / or fluid conduit 418 of the sensor housing 400.

[0088] 13a and 13b show an example of a fifth alternative sensor housing 1300 that may be used with differential pressure sensor 200. As shown, the fifth alternative sensor housing 1300 is similar to sensor housing 400. However, the fifth alternative sensor housing 1300 also includes a plug 1302 fitted within its fluid conduit 418. In some examples, the plug 1302 may also be included in sensor housing 400 (and / or alternative sensor housings 500, 600, 700, 800, etc.).

[0089] 13a and 13b, the plug 1302 is connected to the fifth alternative sensor housing 1300 within the fluid conduit 418. In some examples, the plug 1302 can include an engagement feature (e.g., threads) that engages with a complementary engagement feature formed in the fluid conduit 418. In some examples, the plug 1302 can be friction-fit within the fluid conduit 418 of the fifth alternative sensor housing 1300.

[0090] Within each plug 1302 is a hollow plug shaft 1304 that extends through the body of each plug 1302. As shown, the plug shaft 1304 consists of a wide shaft 1304a closer to the input port 416 and a thin shaft 1304b further from the input port 416. The wide shaft 1304a is hex shaped to accommodate, for example, a hex wrench. In some examples, a hex wrench can use the wide shaft 1304a to help connect the plug 1302 to the fifth alternative sensor housing 1300. Both the wide shaft 1304a and the thin shaft 1304b have a diameter smaller than the diameter of each input port 416. In some examples, fluid can enter the fluid conduit 418 via the input port 416 and then travel through the plug shaft 1304 and into the fluid conduit 418.

[0091] In some examples, without the plug 1302, fluid flowing into, out of, and / or across the input port 416 can cause Helmholtz resonance. The Helmholtz resonance can then cause vibrations that adversely affect the measurements of the differential pressure sensor 200 (e.g., via the strain gauge 426). Positioning the plug 1302 just beyond the input port 416 within the fluid conduit 418, along with reducing the diameter of the plug shaft 1304, can help to reduce and / or reduce the Helmholtz resonance, thereby helping to maintain efficient and / or effective operation of the differential pressure sensor 200.

[0092] Figure 14 illustrates an example of an alternative differential pressure sensor 1400 and an alternative adapter 1600. The alternative differential pressure sensor 1400 illustrated in Figure 14 is similar to the differential pressure sensor 200 illustrated in Figure 2. For example, where the differential pressure sensor 200 of Figure 2 includes the sensor cover 300, the sensor housing 400, and the sensing circuit 900, the alternative differential pressure sensor 1400 similarly includes an alternative sensor cover 1500, a sixth alternative sensor housing 1700, and an alternative sensing circuit 1800.

[0093] 14 and 15 show an example of an alternative sensor cover 1500. As shown, the alternative sensor cover 1500 is similar (and / or identical) to the sensor cover 300 shown in FIG. 3, but with some different elements. For example, the sensor I / O connector 304 is attached to the top of the alternative sensor cover 1500 in the example of FIGS. 14 and 15 (rather than attached to the front as in the sensor cover 300 of FIGS. 2 and 3). The alternative sensor cover 1500 is shown as being attached to the sixth alternative sensor housing 1700 via screw fasteners 1402 inserted through aligned cover fastener holes 1502 / 1702 on the sides of the alternative sensor cover 1500 and the sixth alternative sensor housing 1700 (rather than via cover fasteners 202 inserted through aligned holes 302 / 402 on the front / back of the sensor cover 300 and the sensor housing 400 shown in FIGS. 2-4).

[0094] In the example of Figure 14, alternative differential pressure sensor 1400 and sixth alternative sensor housing 1700 are shown attached to alternative adapter 1600. Figures 16a-16d show various views of alternative adapter 1600. As shown, alternative adapter 1600 is similar (and / or identical) to adapter 1000 shown in Figures 10-12, but with some differences.

[0095] For example, while the adapter 1000 shown in Figures 10-12 has adapter fluid conduits 1018 that extend generally parallel to the y-axis along their entire length, the alternative adapter 1600 includes an alternative adapter fluid conduit 1618 that extends generally parallel to the y-axis in some portions and generally parallel to the z-direction in other portions. A plug 1602 is shown sealing (e.g., in combination with an O-ring) an opening in the portion of the alternative adapter fluid conduit 1618 that extends in the z-direction. In some examples, the opening is created when machining at least the portion of the alternative adapter fluid conduit 1618 that is oriented in the z-direction.

[0096] As another example, while the adapter 1000 shown in Figures 10-12 is shown to be sized to match the profile of the sensor housing 400, the alternative adapter 1600 shown in Figures 14 and 16a-16d has a larger profile than the sixth alternative sensor housing 1700. The larger profile of the alternative adapter 1600 (e.g., relative to the sixth alternative sensor housing 1700) allows the adapter fastener channel 1052 to be positioned out of alignment with the sixth alternative sensor housing 1700. This allows the adapter fastener channel 1052 (and / or the adapter fastener 1054) to be more easily accessible (e.g., when the alternative adapter 1600 is attached to the sixth alternative sensor housing 1700).

[0097] Figures 17a-17d show an example of a sixth alternative sensor housing 1700 for use with the alternative differential pressure sensor 1400 of Figure 14. As shown, the sixth alternative sensor housing 1700 is similar (and / or identical) to the sensor housing 400 of Figures 4a-4f, but with some elements differing. For example, the sixth alternative sensor housing 1700 includes a sixth alternative sensor tube 1722 that is similar to the sensor tube 400 of the sensor housing 400.

[0098] 4a-g, the sixth alternative sensor tube 1722 is separated from the second alternative body 1704 of the sixth alternative sensor housing 1700. Similar to the sensor tube 422 of FIGS. 4a-g, this separation and / or isolation of the sixth alternative sensor tube 1722 can help isolate the strain gauge 426 from most of the bending and / or bulging effects experienced by the sixth alternative body 1704.

[0099] However, unlike the sensor tube 400 of the sensor housing 400, the sixth alternative sensor tube 1722 (and / or fluid conduit 418) of the sixth alternative sensor housing 1700 terminates at a sensor tube top wall 1799 instead of a diaphragm 424. In some examples, the body 1704, the sixth alternative sensor tube 1722, and the sensor tube top wall 1799 of the sixth alternative sensor housing 1700 can comprise one integral, continuous, machined piece of material (e.g., steel and / or other metal) without any welded connections.

[0100] 17a-17d, the sixth alternative sensor housing 1700 includes strain gauges 426 attached, fastened, glued, and / or otherwise joined to opposing exterior sides of a cylindrical sidewall of the sixth alternative sensor tube 1722 (e.g., instead of being attached to the diaphragm 424). In the example of FIGS. 17a-17d, the cylindrical sidewall of the sixth alternative sensor tube 1722 is also shown as being substantially thinner than the sensor tube top wall 1799. In some examples, the relatively thin width of the sidewall of the sixth alternative sensor tube 1722 can cause fluid pressure of the working fluid in the fluid conduit 418 to force the sidewall of the sixth alternative sensor tube 1722 to flex, expand, deform, and / or bend outwardly (e.g., in the x-direction and / or z-direction). As the sidewall of the sixth alternative sensor tube 1722 expands / deforms, the strain gauge 426 also expands / deforms.

[0101] In some examples, the resistance (and / or impedance) of each strain gauge 426 is determined by the degree to which its sensor tube sidewall stretches (and / or flexes, deforms, expands, etc.). In some examples, this configuration allows the strain gauges 426 to measure the hoop stress on (and / or experienced by) the sixth alternative sensor tube 1722. In some examples, locating a strain gauge 426 on either side of each sixth alternative sensor tube 1722 helps to ensure accurate and / or effective measurements and / or useful differential pressure determinations.

[0102] In some examples, the sixth alternative sensor tube 1722 of the sixth alternative sensor housing 1700 can be surrounded by a trepanned annular groove, for example, as shown in Figures 6a-8c. Although shown in the examples of Figures 17a-17d as extending away from the sixth alternative body 1704, in some examples, the sixth alternative sensor tube 1722 of the sixth alternative sensor housing 1700 can instead be flush with or recessed within the sixth alternative body 1704, for example, as shown in Figures 6a-6c and 8a-8c.

[0103] Figure 18 illustrates an alternative sensing circuit 1800 that may be used with alternative differential pressure sensor 1400. As shown, alternative sensing circuit 1800 is similar (and / or identical) to sensing circuit 900a of Figure 9, except that strain gauges 426c1, 426c2, 426d1, 426d2 are used instead of strain gauges 426a1, 426a2, 426b1, 426b2, and output signal 1804 is generated instead of output signal 904.

[0104] In some examples, the alternative sensing circuit 1800 is configured to generate (e.g., output via an output signal pin of the sensor I / O connector 304) an output signal 1804. In some examples, the output signal 1804 represents a difference in resistance between the strain gauges 426 joined to different sixth alternative sensor tubes 1722.

[0105] 9, except that the output signal 1804 is representative of the difference in resistance between strain gauge 426c1 and / or strain gauge 426c2 (rather than strain gauge 426a1, 426a2, 426b1, 426b2) and strain gauge 426d1 and / or strain gauge 426d2. Because the resistance of the strain gauges 426 bonded to a particular sixth alternative sensor tube 1722 should be approximately equal, differences in resistance between the strain gauges 426 of different diaphragms 424 can be the result of differences in the deflection (and / or strain, deformation, etc.) of the sixth alternative sensor tube 1722. Additionally, since the deflection (and / or strain, deformation, etc.) of the sixth alternative sensor tube 1722 is due to fluid pressure in the fluid conduits 418, the output signal may represent the difference in fluid pressure in each of the fluid conduits 418.

[0106] The differential pressure sensor 200 / 1400 disclosed herein has a unique design that makes it particularly suitable for the dynamic high pressure hydraulic system 100. For example, the one-piece design of its sensor housing 400 (and / or alternative sensor housings 500, 600, 700, 800, 1300, 1700) enhances the durability of the sensor 200 / 1400. Additionally, the use of foil strain gauges 426 (rather than piezoelectric strain gauges, for example) ensures continued functionality under the unique stresses imposed by the dynamic high pressure hydraulic system 100. Additionally, the sensor tube 422 helps to isolate the diaphragm 424 and strain gauges 426 from some of the warping / bending stresses that the body 404 of the sensor housing 400 may experience due to very high fluid pressures.

[0107] Although the method and / or system have been described with reference to certain specific embodiments, those skilled in the art will recognize that various modifications can be made and equivalents can be substituted without departing from the scope of the method and / or system. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from its scope. Therefore, the method and / or system is not limited to the particular embodiments disclosed, but it is contemplated that the method and / or system will include all embodiments falling within the scope of the appended claims.

[0108] As used herein, "and / or" means any one or more of the items in the list linked by "and / or." As an example, "x and / or y" means any element of the three-element set {(x),(y),(x,y)}. In other words, "x and / or y" means "one or both of x and y." As another example, "x, y and / or z" means any element of the seven-element set {(x),(y),(z),(x,y),(x,z),(y,z),(x,y,z)}. In other words, "x, y and / or z" means "one or more of x, y and z."

[0109] As used herein, the term "for example" emphasizes a list of one or more non-limiting examples, instances, or illustrations.

[0110] As used herein, the terms "coupled," "coupled to," and "coupled with" refer to a structural and / or electrical connection, whether by attaching, adhering, connecting, joining, fastening, linking, and / or otherwise securing. As used herein, the term "attach" refers to attaching, adhering, connecting, joining, fastening, linking, and / or otherwise securing. As used herein, the term "connect" refers to attaching, adhering, connecting, joining, fastening, linking, and / or otherwise securing.

[0111] As used herein, the terms "circuitry" and "circuitry" refer to physical electronic components (i.e., hardware) and any software and / or firmware ("code") that may comprise, be executed by, and / or be otherwise associated with the hardware. As used herein, for example, a particular processor and memory may include a first "circuitry" when executing a first one or more lines of code, and a second "circuitry" when executing a second one or more lines of code. As used herein, whenever circuitry includes the hardware and code (if either is necessary) necessary to perform a function, the circuitry is "operable" and / or "configured" to perform that function, regardless of whether performance of that function is disabled or enabled (e.g., by a user-configurable setting, factory trim, etc.).

[0112] As used herein, control circuitry can include digital and / or analog circuitry, discrete and / or integrated circuitry, microprocessors, DSPs, etc., software, hardware and / or firmware that constitutes part or all of the controller and / or is located on one or more boards used to control the welding process and / or devices such as the power supply or wire feeder.

[0113] As used herein, the term "processor" refers to processing devices, apparatus, programs, circuits, components, systems, and subsystems, whether implemented in hardware, tangibly embodied software, or both, and whether programmable or not. As used herein, the term "processor" includes, but is not limited to, one or more computing devices, hardwired circuits, devices and systems that modify signals, devices and machines for controlling systems, central processing units, programmable devices and systems, field programmable gate arrays, application specific integrated circuits, systems on chips, systems with discrete elements and / or circuits, state machines, virtual machines, data processors, processing facilities, and any combination of the above. A processor may be, for example, any type of general purpose microprocessor or general purpose microcontroller, a digital signal processing (DSP) processor, an application specific integrated circuit (ASIC), a graphics processing unit (GPU), a reduced instruction set computer (RISC) processor with an advanced RISC machine (ARM) core, etc. A processor may be coupled to and / or integrated into a memory device.

[0114] As used herein, the terms "memory" and / or "memory device" refer to computer hardware or circuitry that stores information for use by a processor and / or other digital devices. The memory and / or memory device can be any suitable type of computer memory or any other type of electronic storage medium, such as read-only memory (ROM), random access memory (RAM), cache memory, compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), computer readable medium, etc. Memory may include, for example, non-transitory memory, non-transitory processor-readable medium, non-transitory computer-readable medium, non-volatile memory, dynamic RAM (DRAM), volatile memory, ferroelectric RAM (FRAM), first-in-first-out (FIFO) memory, last-in-first-out (LIFO) memory, stacked memory, non-volatile RAM (NVRAM), static RAM (SRAM), cache, buffer, semiconductor memory, magnetic memory, optical memory, flash memory, flash card, compact flash card, memory card, secure digital memory card, micro card, mini card, expansion card, smart card, memory stick, multimedia card, picture card, flash storage, subscriber identity module (SIM) card, hard drive (HDD), solid state drive (SSD), etc. Memory may be configured to store code, instructions, applications, software, firmware, and / or data and may be external, internal, or both to the processor.

Claims

1. A differential pressure sensor, a sensor housing having a first input port and a second input port; a first sensor tube connected to the sensor housing at a first tube housing end, the first sensor tube extending from the first tube housing end to a first conduit end spaced from the sensor housing; a second sensor tube connected to the sensor housing at a second tube housing end, the second sensor tube extending from the second tube housing end to a second conduit end isolated from the sensor housing; a first fluid conduit extending from the first input port, through the sensor housing and the first sensor tube, to the first conduit end, the first sensor tube configured to undergo a first deflection in response to a first fluid pressure in the first fluid conduit; a second fluid conduit extending from the second input port, through the sensor housing and the second sensor tube, to the second conduit end, the second sensor tube configured to undergo a second deflection in response to a second fluid pressure in the second fluid conduit; a first circuit element coupled to the first sensor tube, the first circuit element having a first electrical characteristic that is determined by the first deflection of the first sensor tube; a second circuit element coupled to the second sensor tube, the second circuit element having a second electrical characteristic determined by the second deflection of the second sensor tube; a sensing circuit electrically connected to the first circuit element and the second circuit element, the sensing circuit configured to determine a pressure differential between the first fluid pressure in the first fluid conduit and the second fluid pressure in the second fluid conduit based on the first electrical characteristic of the first circuit element and the second electrical characteristic of the second circuit element; A differential pressure sensor comprising:

2. 2. The differential pressure sensor of claim 1, wherein the sensor housing further comprises a first housing end and a second housing end opposite the first housing end, the first housing end comprising the first input port and the second input port, and the second housing end connecting to the first sensor tube or the second sensor tube at the first tube housing end or the second tube housing end.

3. The differential pressure sensor of claim 1 , wherein the first sensor tube or the second sensor tube is recessed within the sensor housing such that the sensor housing surrounds the first sensor tube or the second sensor tube.

4. The differential pressure sensor of claim 1 , wherein the sensor housing is constructed from a metallic material.

5. The sensor housing includes: a first groove surrounding a first portion of the first sensor tube such that the first portion of the first sensor tube is isolated from the sensor housing; a second groove surrounding a second portion of the second sensor tube such that the second portion of the second sensor tube is isolated from the sensor housing; and The differential pressure sensor of claim 1 further comprising:

6. 2. The differential pressure sensor of claim 1, wherein the first circuit element comprises a first resistor, the second circuit element comprises a second resistor, the first electrical characteristic comprises a first resistance, and the second electrical characteristic comprises a second resistance.

7. The differential pressure sensor of claim 6 , wherein the first circuit element comprises a first strain gauge and the second circuit element comprises a second strain gauge.

8. The differential pressure sensor of claim 7 , wherein the first strain gauge and the second strain gauge are comprised of foil.

9. The differential pressure sensor of claim 1 , wherein the sensor housing, the first sensor tube, and the second sensor tube comprise a single continuous piece of machined metal.

10. the first sensor tube comprises a first inner sensor tube portion within the first fluid conduit and a first outer sensor tube portion outside the first fluid conduit; the second sensor tube comprises a second inner sensor tube wall within the second fluid conduit and a second outer sensor tube portion exterior to the second fluid conduit; the first circuit element is joined to the first outer sensor tube portion; the second circuit element is joined to the second outer sensor tube portion; The differential pressure sensor according to claim 1 .

11. 1. A hydraulic system comprising: a hydraulic system including a system housing enclosing a first fluid volume separated from a second fluid volume; A differential pressure sensor, a sensor housing including a first input port in fluid communication with the first fluid volume and a second input port in fluid communication with the second fluid volume; a first sensor tube connected to the sensor housing at a first tube housing end, the first sensor tube extending from the first tube housing end to a first conduit end spaced from the sensor housing; a second sensor tube connected to the sensor housing at a second tube housing end, the second sensor tube extending from the second tube housing end to a second conduit end isolated from the sensor housing; a first fluid conduit extending from the first input port, through the sensor housing and the first sensor tube, to the first conduit end, the first sensor tube configured to undergo a first deflection in response to a first fluid pressure in the first fluid conduit; a second fluid conduit extending from the second input port, through the sensor housing and the second sensor tube, to the second conduit end, the second sensor tube configured to undergo a second deflection in response to a second fluid pressure in the second fluid conduit; a first circuit element coupled to the first sensor tube, the first circuit element having a first electrical characteristic that is determined by the first deflection of the first sensor tube; a second circuit element coupled to the second sensor tube, the second circuit element having a second electrical characteristic determined by the second deflection of the second sensor tube; a sensing circuit electrically connected to the first circuit element and the second circuit element, the sensing circuit being configured to determine a pressure differential between a fluid in the first fluid volume of the hydraulic device and a fluid in the second fluid volume of the hydraulic device based on the first electrical characteristic of the first circuit element and the second electrical characteristic of the second circuit element; A differential pressure sensor comprising: A hydraulic system comprising:

12. 12. The hydraulic system of claim 11, wherein the sensor housing further comprises a first housing end and a second housing end opposite the first housing end, the first housing end comprising the first input port and the second input port, and the second housing end connecting to the first sensor tube or the second sensor tube at the first tube housing end or the second tube housing end.

13. The hydraulic system of claim 11 , wherein the first sensor tube or the second sensor tube is recessed within the sensor housing such that the sensor housing surrounds the first sensor tube or the second sensor tube.

14. The hydraulic system of claim 11 , wherein the sensor housing is constructed from a metallic material.

15. The sensor housing includes: a first groove surrounding a first portion of the first sensor tube such that the first portion of the first sensor tube is isolated from the sensor housing; a second groove surrounding a second portion of the second sensor tube such that the second portion of the second sensor tube is isolated from the sensor housing; The hydraulic system of claim 11 further comprising:

16. 12. The hydraulic system of claim 11, wherein the first circuit element comprises a first resistor, the second circuit element comprises a second resistor, the first electrical characteristic comprises a first resistance, and the second electrical characteristic comprises a second resistance.

17. 17. The hydraulic system of claim 16, wherein the first circuit element comprises a first strain gauge and the second circuit element comprises a second strain gauge.

18. The hydraulic system of claim 17 , wherein the first strain gauge and the second strain gauge are comprised of foil.

19. The hydraulic system of claim 11 , wherein the sensor housing, the first sensor tube, and the second sensor tube comprise a single continuous piece of machined metal.

20. the first sensor tube comprises a first inner sensor tube portion within the first fluid conduit and a first outer sensor tube portion outside the first fluid conduit; the second sensor tube comprising a second inner sensor tube portion within the second fluid conduit and a second outer sensor tube portion exterior to the second fluid conduit; the first circuit element is joined to the first outer sensor tube portion; the second circuit element is joined to the second outer sensor tube portion; The hydraulic system of claim 11.

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