Ultrasonic cavitation sensor

Abstract

An apparatus for sensing cavitation in a liquid flowing through a conduit in a housing, the apparatus comprising an ultrasound transducer system having one or more ultrasound transducers attached to the housing and arranged in acoustic communication with the liquid, and control electronics connected to the ultrasound transducer system. The control electronics are configured to drive the transducer system to transmit an ultrasonic signal through the flowing liquid, wherein the transducer system receives the ultrasonic signal and generates an electronic cavitation detection signal representative of an intensity of the received ultrasonic signal. The control electronics are further configured to process the cavitation detection signal to provide a cavitation measurement signal indicative of whether the ultrasound signal interacts with one or more cavitation bubbles, evaluate the cavitation measurement signal to determine whether one or more alert conditions are satisfied, and outputting an alarm signal when each of the cavitation alarm conditions is satisfied.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 356,201, filed on June 28, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to sensors for detecting cavitation and other properties of flow through liquid pumps and liquid piping systems. Background Art

[0004] Cavitation is a phenomenon that frequently occurs in liquid pumps and piping systems. Cavitation can be caused by restrictions in the flow in a pump or pipe, or by other conditions that create low pressures leading to the formation of cavitation vapor bubbles. Cavitation bubbles differ from air bubbles in that cavitation bubbles or voids consist of vapor surrounding a liquid medium. For example, in pumps and piping systems for water, cavitation bubbles consist of water vapor (i.e., cold steam) rather than air. Cavitation vapor bubbles may collapse on the surface of a pump impeller, valve, or pipe and cause surface damage due to the extreme local pressures involved. Detection of cavitation is important in order to control its occurrence and minimize damage to expensive components.

[0005] Currently, cavitation is detected by indirect sensing methods. It is known to detect cavitation using acoustic sensors that listen for the sound produced by collapsing cavitation bubbles when they impact on the surface of a pump, valve, tube, or other component of a liquid flow system. Another known method for indirectly detecting cavitation is to sense vibrations on a pump housing or piping. Still other methods for indirectly detecting cavitation include sensing significant changes in pump impeller speed or maximum current, or measuring significant pressure drops in a liquid flow system. The above known methods detect cavitation artifacts (e.g., noise, vibration, pump behavior) when cavitation vapor bubbles cause damage to system components, and therefore have limited value in preventing such damage. The use of acoustic sensors is not suitable for noisy environments.

[0006] Cavitation can be detected directly by visual observation, however this requires the use of transparent tubing in the liquid flow system and the cavitation vapor bubbles must be large enough to allow visual or optical observation.

[0007] There is a need for improved solutions for detecting cavitation. Summary of the invention

[0008] The present disclosure provides an apparatus and method for directly sensing cavitation bubbles in a liquid flowing through a conduit before the cavitation bubbles collapse on a surface.

[0009] In one embodiment, the cavitation sensor module may include a pipe segment suitable for installation in a pipe of a liquid flow system, one or more first transducer plugs each having a first ultrasonic transducer for transmitting an ultrasonic signal, one or more second transducer plugs each having a second ultrasonic transducer for receiving an ultrasonic signal from the first ultrasonic transducer paired therewith, and a controller circuit board assembly connected to each first ultrasonic transducer and each second ultrasonic transducer. The cavitation sensor module may also include a housing for protecting the first transducer plug and the second transducer plug and the controller circuit board assembly, and for fixing the transducer plug and the controller circuit board assembly to the pipe segment.

[0010] The controller circuit board assembly may include an electronic controller and associated circuitry configured to execute stored programming instructions to drive each first ultrasonic transducer and process the cavitation detection signal generated by each second ultrasonic transducer to establish a cavitation measurement signal. The electronic controller may execute stored programming instructions to compare the cavitation measurement signal with a predetermined cavitation threshold. The controller may be programmed and configured such that when the amplitude of the cavitation measurement signal drops below the cavitation threshold, an alarm is signaled by the controller. The intensity of the ultrasonic signal generated by each first ultrasonic transducer and the gain applied to the cavitation detection signal generated by each second ultrasonic transducer when the ultrasonic signal is received may be controlled and adjusted by the controller. The count of bubbles present in the flowing liquid and / or the accumulation of cavitation events may be calculated by the controller to provide additional information to the user.

[0011] The housing can be a multi-piece housing having a plurality of components that can be disassembled and assembled to install the cavitation sensor module in a liquid flow system. In one embodiment, the housing includes: a center piece sized to receive a controller circuit board assembly and a first radial portion of a pipe segment; a cover piece removably attached to the center piece and sized to cover the controller circuit board assembly; and a retainer removably attached to the center piece and sized to receive a second radial portion of the pipe segment opposite the first radial portion of the pipe segment to secure the housing to the pipe segment.

[0012] In another embodiment, the cavitation sensor device is similar to the sensor module outlined above, except that the control electronics are housed in a closed control unit located remotely from the housing (e.g., a pipe segment, pump housing, valve housing, fitting, or other housing) in which the fluid flow conduit is located.

[0013] In further variations, the cavitation sensor device does not include its own housing defining a fluid conduit and is mounted on a housing of an existing component in the fluid flow system (e.g., a tube, a pump housing, a valve housing, a fitting, or another housing). Further variations include non-invasive clamp-on variations and bonded variations.

[0014] The cavitation sensing apparatus of the present disclosure may include a user interface connected to the control electronics, such as an external computing device. The user interface may be configured to display a cavitation measurement signal and / or a value representing an instantaneous intensity of the cavitation measurement signal. The user interface may be configured to receive a first variable user input for establishing a cavitation alarm set point. The user interface may also be configured to receive a second variable user input for establishing a cavitation error count setting to reduce redundant alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The nature and mode of operation of the present disclosure will now be more fully described in the following detailed description taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1A is a schematic diagram of an ultrasonic cavitation sensor according to an embodiment of the present disclosure viewed along an axial flow direction of a tube conduit associated with the cavitation sensor, wherein no cavitation bubbles are present in a liquid flowing through the tube;

[0017] Figure 1B is similar to Figure 1A A schematic diagram of a schematic diagram of a method of manufacturing a device for ...

[0018] Figure 1C is a schematic diagram of an ultrasonic cavitation sensor according to another embodiment of the present disclosure viewed along an axial flow direction of a tube conduit associated with the cavitation sensor, wherein no cavitation bubbles are present in a liquid flowing through a pump conduit;

[0019] Figure 1D is similar to Figure 1C A schematic diagram of a schematic diagram of a method of manufacturing a device for ...

[0020] Figure 2 is a perspective view of an ultrasonic cavitation sensor module according to an embodiment of the present disclosure;

[0021] Figure 3 yes Figure 2 A side view of a cavitation sensor module is shown;

[0022] Figure 4 yes Figure 2 Another perspective view of the cavitation sensor module is shown with a top cover of the housing of the cavitation sensor module removed;

[0023] Figure 5yes Figure 2 Another perspective view of the cavitation sensor module is shown with the entire housing of the cavitation sensor module removed;

[0024] Figure 6 It is observed along the axial flow direction of the pipe section of the cavitation sensor module Figure 5 a view of the cavitation sensor module with the cover removed;

[0025] Figure 7 yes Figure 2 An exploded perspective view of a transducer plug of a cavitation sensor module is shown;

[0026] Figure 8 yes Figure 7 a cross-sectional perspective view of the transducer plug shown;

[0027] Fig. 9 yes Figure 2 A schematic block diagram of an electronic controller board assembly of a cavitation sensor module is shown;

[0028] Fig.10 is a perspective view of an ultrasonic cavitation sensor device according to another embodiment of the present disclosure;

[0029] Fig.11 yes Fig.10 a perspective view of a control unit of an ultrasonic cavitation sensor device shown with a front panel of the control unit removed to reveal internal components of the control unit;

[0030] Fig.12 yes Fig.10 A cross-sectional perspective view of a pipe section and ultrasonic transducer system of an ultrasonic cavitation sensor device is shown;

[0031] FIG. 13A to FIG. 13C is a perspective view showing various types of pipe segments that may be used in an ultrasonic cavitation sensor device;

[0032] Fig.14 is a perspective view of an ultrasonic transducer plug of an ultrasonic cavitation sensor device;

[0033] Fig.15 yes Fig.14 A cross-sectional view of the ultrasonic transducer plug shown;

[0034] Fig.16 is a perspective view of a pump formed in accordance with a variation of the present disclosure, wherein an ultrasonic cavitation sensor apparatus of the present disclosure is associated with a housing of the pump;

[0035] Fig.17 yes Fig.16 A partially cut-away side view of the pump and transducer portions of the ultrasonic cavitation sensor device shown;

[0036] Fig.18 is a perspective view of a valve formed in accordance with a variation of the present disclosure, wherein an ultrasonic cavitation sensor apparatus of the present disclosure is associated with a housing of the valve;

[0037] Fig.19 yes Fig.18 An axial cross-sectional view of the valve and ultrasonic cavitation sensor apparatus shown;

[0038] Fig. 20 is a perspective view of a clamp-on ultrasonic cavitation sensor module connected to a pipe segment according to another embodiment of the present disclosure;

[0039] Fig.21 yes Fig. 20 A cross-sectional view of the clamp-on module and pipe segment shown;

[0040] Fig. 22 yes Fig. 20 A cross-sectional view of the ultrasonic transducer plug of the clip-on module shown;

[0041] Fig.23 is a perspective view showing an ultrasonic cavitation sensor arrangement using a bonded transducer on a flow reducer fitting according to another embodiment of the present disclosure;

[0042] Fig.24 yes Fig.23 An exploded perspective view of the ultrasonic cavitation sensor arrangement shown;

[0043] Fig.25 yes Fig.23 A cross-sectional view of the ultrasonic cavitation sensor arrangement structure shown;

[0044] Fig.26A is a diagram illustrating a user interface display screen of an ultrasonic cavitation sensor device, wherein no cavitation bubbles are present in a liquid monitored by the device; and

[0045] Fig.26B is similar to Fig.26A A view of a diagram showing the presence of cavitation bubbles in a liquid monitored by the device. DETAILED DESCRIPTION

[0046] Figure 1A and Figure 1BA configuration for direct ultrasonic detection of cavitation bubbles before they collapse on a surface is schematically illustrated. In both figures, a liquid flows through a conduit 1 of a tube 2 in the axial direction of the tube conduit (i.e., in a direction perpendicular to the plane of the drawing). Mounted on one side of the tube 2 is a first transducer plug 4 that extends through the wall of the tube and has a first ultrasonic transducer 5 that is acoustically connected to the liquid flowing through the tube. Mounted on the opposite side of the tube 2 is a second transducer plug 6 that extends through the wall of the tube and has a second ultrasonic transducer 7 that is acoustically connected to the liquid flowing through the tube conduit 1. As shown, the second ultrasonic transducer 7 faces the first ultrasonic transducer 5 across the liquid flowing through the tube conduit 1 in a transverse direction (perpendicular to the axial direction of the tube conduit). The first ultrasonic transducer 5 can be driven to transmit an ultrasonic signal in the form of a series of waves toward the second ultrasonic transducer 7, which propagates through the liquid flowing in the tube conduit 1. The second ultrasonic transducer 7 is arranged to receive the ultrasonic signal transmitted by the first ultrasonic transducer 5, and is configured to generate an electronic cavitation detection signal representing the intensity of the ultrasonic signal received from the first ultrasonic transducer 5. For example, the paired first ultrasonic transducer 5 and second ultrasonic transducer 7 may be piezoelectric transducers operating in the ultrasonic frequency range.

[0047] like Figure 1A As illustrated, if there are no cavitation bubbles in the liquid flowing through the tube conduit 1 to block the ultrasonic signal as it travels across the liquid in the tube conduit 1, the cavitation detection signal generated by the second ultrasonic transducer 7 has a relatively high amplitude. Figure 1B As shown in the example, if there are one or more cavitation bubbles in the flowing liquid, the ultrasonic signal is Figure 1A The greater degree of attenuation in the second ultrasonic transducer 7 results in less energy being received, and Figure 1A The cavitation detection signal generated by the second ultrasonic transducer 7 has a reduced amplitude compared to the cavitation-free condition. The strength of the cavitation detection signal is a relative indicator of the size and / or number of cavitation bubbles present between the first ultrasonic transducer 5 and the second ultrasonic transducer 7.

[0048] As described in detail below, an electronic controller and associated circuitry connected to the ultrasonic transducers 5, 7 can be configured to execute stored programming instructions to drive the first ultrasonic transducer 5 and process the cavitation detection signal generated by the second ultrasonic transducer 7 to establish a cavitation measurement signal and compare the cavitation measurement signal to a predetermined cavitation threshold. The controller can be programmed and configured so that when the amplitude of the cavitation measurement signal drops below the cavitation threshold, an alarm is signaled by the controller. The intensity of the ultrasonic signal generated by the first ultrasonic transducer 5 and the gain applied to the cavitation detection signal generated by the second ultrasonic transducer 7 when the ultrasonic signal is received can be controlled and adjusted by the controller. The count of bubbles present in the flowing liquid or the accumulation of cavitation can be calculated by the controller to provide additional information to the user.

[0049] Figure 1C and Figure 1D Schematically illustrates a variant configuration for direct ultrasonic detection of cavitation bubbles before they collapse on the inner surface of a liquid conduit 1 operating using retro-reflection of ultrasonic signals, also known as "pulse-echo" mode of operation. Figure 1A and Figure 1B In contrast to the illustrated configuration, Figure 1C and Figure 1D The configuration has a single ultrasonic transducer 5 that operates as both a transmitter and a receiver. The ultrasonic transducer 5 can be driven to transmit an ultrasonic signal propagating through a liquid flowing in the liquid conduit 1 toward an opposing inner wall surface 3 of the conduit 1, and is arranged to receive the ultrasonic signal after the ultrasonic signal has been reflected back from the surface 3 to the ultrasonic transducer 5. The ultrasonic transducer 5 is configured to generate an electronic cavitation detection signal representative of the intensity of the received ultrasonic signal. In a "pulse echo" configuration, an electronic controller and associated circuitry can be connected to the ultrasonic transducer 5 and configured to execute stored programmed instructions to drive the ultrasonic transducer 5, and in a manner similar to that described above with respect to Figure 1A and Figure 1B The cavitation detection signal generated by the ultrasonic transducer 5 is processed in a manner similar to that described for the second ultrasonic transducer 7 .

[0050] Figures 2 to 9 A cavitation sensor module 10 formed in accordance with an exemplary embodiment of the present disclosure is illustrated. The cavitation sensor module 10 is intended to be installed in a piping system (not shown) for conveying a fluid flow. For example, the cavitation sensor module 10 may be installed in industrial and structural hydraulic systems, liquid cooling systems (such as those used at computer server farms), drinking water and wastewater systems, mining and agricultural liquid flow systems, and any liquid pumping system where there is a potential for cavitation damage.

[0051] The cavitation sensor module 10 may include a pipe segment 12, one or more first transducer plugs 14 each having a first ultrasonic transducer 15, one or more second transducer plugs 16 each having a second ultrasonic transducer 17 paired with the corresponding first ultrasonic transducer 15, and a controller circuit board assembly 18 connected to each first ultrasonic transducer 15 and each second ultrasonic transducer 17. Figure 5 and Figure 6 , the connection wiring 19 for connecting only one pair of ultrasonic transducers 15, 17 to the controller circuit board assembly 18 is shown, and for the sake of clarity, the connection wiring for additional ultrasonic transducers 15, 17 is not shown. However, if the sensor module 10 uses an additional ultrasonic transducer, the additional ultrasonic transducer is also connected to the controller circuit board assembly 18. The cavitation sensor module 10 may also include a housing 20 for protecting the first and second transducer plugs 14, 16 and the controller circuit board assembly 18, and for fixing the transducer plugs and the controller circuit board assembly to the pipe segment 12.

[0052] like Figure 5 As best seen in FIG. 1 , the pipe segment 12 may be a straight length of metal or plastic pipe that defines a liquid flow conduit 30 through which liquid flows. The pipe segment 12 may include couplings 32 at opposite ends thereof for connecting the pipe segment 12 to the piping of the liquid flow system in which the cavitation sensor module 10 is installed. For example, the couplings 32 may be standard pipe couplings, each having an internal threaded portion 34 for mating with system piping and an external flat portion 36 for facilitating the application of torque to the pipe segment 12. The configuration of the couplings 32 may be selected to be compatible with the piping specifications of the liquid flow system in which the cavitation sensor module 10 is installed. The pipe segment 12 may also include a plurality of ports 38 extending through the wall of the pipe segment, such as through the wall of the pipe segment in a radial direction, for receiving and positioning the transducer plugs 14 and 16. Of course, the pipe segment 12 may not be a straight segment, that is, the liquid flow conduit 30 may be curved to change the flow direction.

[0053] Now see Figure 7 and Figure 81 to describe the transducer plugs 14, 16 according to embodiments of the present disclosure. Each transducer plug 14, 16 may include a shell 40 sized to fit within a corresponding port 38 in a pipe segment 12 in a slidable manner. The shell 40 may hold an associated ultrasonic transducer 15 or 17 near its inner end 41 and define a channel 42 through which wiring 19 may pass for connecting the ultrasonic transducer to a controller circuit board assembly 18 via an electrical connector 43. The shell 40 may be made of metal (e.g., stainless steel) or plastic. The ultrasonic transducer 15 or 17 may be assembled into an insulating carrier 44 and mounted within the shell 40. The transducer plug shell 40 and its corresponding port 38 may be cylindrical in shape as shown in the accompanying drawings, or they may be non-cylindrical in shape. In the event of a malfunction of the ultrasonic transducer, the use of the transducer plug 14, 16 slidably assembled within the corresponding port 38 in the pipe segment 12 facilitates efficient repair or replacement of the associated ultrasonic transducer 15, 17.

[0054] The ultrasonic transducers 15, 17 can be piezoelectric transducer elements. As non-limiting examples, the ultrasonic transducers 15, 17 can be made of any of several materials suitable for generating ultrasonic signals, such as lead zirconate titanate (PZT) or lead metaniobate, quartz crystal, or other piezoelectric materials. Ceramic transducer elements made of PZT supplied by Piezo Kinetics Inc. (PKI) or APC International can be used to practice the present disclosure. The ceramic transducer element considered suitable in the prototype of the cavitation sensor module 10 is a PZT disk, 10.2 mm outer diameter × 1 mm thick, sold by APC International as part number 973). The ultrasonic transducers 15, 17 can have a shape such as Figure 7 and Figure 8 The insulating carrier 44 provides electrical isolation between the ultrasonic transducers 15 , 17 and the material of the plug housing 40 .

[0055] The transducer plugs 14 and 16 may be manufactured to the same specifications, incorporating the same model or part number of ultrasonic transducers 15 and 17, in order to benefit from economies of scale in production. The current embodiment has four ports in the tube so two pairs of ultrasonic transducers 15, 17 can be used to redundantly measure cavitation.

[0056] In a variation of the above embodiment, a single ultrasonic transducer may be used to replace each ultrasonic transducer pair 15, 17. In this case, the single ultrasonic transducer will both transmit and receive ultrasonic signals in a "pulse-echo" mode of operation. Multiple ultrasonic transducers operating in pulse-echo mode can be used to redundantly measure cavitation.

[0057] Fig. 9 Schematically illustrated is an embodiment of an electronic controller board assembly 18. The controller board assembly 18 may include a programmable microcontroller 50, an internal programming header 51 connected to the microcontroller 50, one or more digital memory devices 52 connected to the microcontroller 50, a multiplexer 53 connected to the microcontroller 50, and an Ethernet port 55 and a serial port 56 that enable data communication between an external computing device 70 and the microcontroller 50. The internal programming header 51 allows the microcontroller 50 to be programmed in the factory and is not user accessible.

[0058] Power may be supplied to the components of the controller board assembly 18 through a power source / regulator circuit 58 and a brownout detection / watchdog timer circuit 60 connected to the microcontroller 50 .

[0059] The microcontroller 50 may be connected to transmit a drive control signal to each first ultrasonic transducer 15 via a waveform generator circuit 62 and a transmission signal conditioning circuit 64. The intensity and timing of the ultrasonic signal generated by each first ultrasonic transducer 15 may be controlled and adjusted by the microcontroller 50 according to programming instructions (e.g., firmware or software) that can be executed by the microcontroller 50. A user interface may be provided to enable a user to input control parameters and settings that govern the characteristics of the ultrasonic signal generated by each first ultrasonic transducer 15. An external computing device 70 (e.g., a personal computer) may be used as such a user interface. Alternatively or in addition, a touch-sensitive display panel (not shown) incorporated on the housing 20 and connected for data communication with the microcontroller 50 may be used as a user interface.

[0060] The ultrasonic signal transmitted by each first ultrasonic transducer 15 through the liquid in the pipe section 12 can be received by the corresponding second ultrasonic transducer 17. The cavitation detection signal generated by each second ultrasonic transducer 17 upon receiving the ultrasonic signal can be processed by applying a signal gain (i.e., a scaling factor) and a signal filtering at the circuit 66. The amount of gain and filtering characteristics applied to the cavitation detection signal from each second ultrasonic transducer 17 can be controlled and adjusted by the microcontroller 50 according to programming instructions (e.g., firmware or software) that can be executed by the microcontroller 50. The user can input control parameters and settings that govern the gain and filtering characteristics of the cavitation detection signal generated by each second ultrasonic transducer 17 using a user interface (e.g., an external computing device 70) as described above.

[0061] Each circuit 66 provides a cavitation measurement signal to the microcontroller 50. The cavitation measurement signal may be in the form of an analog voltage signal based on the cavitation detection signal from the associated second ultrasonic transducer 17, with signal noise reduced by filtering and signal strength increased by gain / scaling. The cavitation measurement signal may be digitized by an analog-to-digital converter, which may be provided as part of the microcontroller 50.

[0062] The cavitation measurement signal can be evaluated by the microcontroller 50 to determine whether there are cavitation bubbles in the liquid between the first ultrasonic transducer 15 and the second ultrasonic transducer 17 paired therewith at a given measurement time. The microcontroller 50 can be configured to execute programmed instructions, such as firmware or software stored in a memory, so that the microcontroller evaluates the amplitude of the cavitation measurement signal relative to one or more predetermined thresholds stored in the memory 52. ​​The thresholds can be determined based on empirical testing. As a non-limiting example for illustration, a 3.0V output cavitation measurement signal can be generated if there are no cavitation bubbles in the liquid in the conduit 30 between the first ultrasonic transducer 15 and the second ultrasonic transducer 17, and a 1.0V output cavitation measurement signal can be generated if there are all air in the conduit 30 between the first ultrasonic transducer 15 and the second ultrasonic transducer 17. Therefore, during operation, a cavitation measurement signal below 3.0V will indicate the presence of at least one cavitation bubble, and there will be a correlation between the cavitation measurement signal and the degree of cavitation present in the liquid. The closer the cavitation measurement signal is to 1.0V, the greater the cavitation level in the liquid.

[0063] An alarm threshold may be assigned corresponding to a cavitation bubble level that is approaching but has not yet reached a level of cavitation bubbles known to cause damage to system surfaces or components. The microcontroller 50 may be programmed to turn on an alarm if the cavitation measurement signal exceeds the alarm threshold. Continuing with the non-limiting example of the preceding paragraph, an alarm threshold such as 2.0V may be assigned, and if the cavitation measurement signal drops below the alarm threshold, the microcontroller 50 will activate an alarm device (e.g., an audio alarm and / or a visual alarm) to indicate the presence of potentially harmful cavitation so that corrective action may be taken to prevent damage to components or surfaces of the liquid flow system. Corrective action may be implemented manually, or may be automated. For example, the pump flow rate may be manually reduced in response to an audio alarm and / or a visual alarm, or automatically reduced in response to an alarm signal from the microcontroller 50.

[0064] As described above, the count of cavitation bubbles present in the flowing liquid or the accumulation of cavitation can be calculated by the microcontroller 50 to provide additional information to the user. The microcontroller 50 can be programmed to detect the duration of time that the cavitation measurement signal "goes low" (i.e., falls below a predetermined threshold). If the cavitation bubbles are relatively large, the detected duration can be used to estimate the total volume of the cavitation bubbles. The detected duration information can also be used by the microcontroller 50 to estimate the flow rate of the liquid flowing through the pipe segment 12. The microcontroller 50 can also be programmed to count the number of cavitation bubbles sensed over time.

[0065] The ability to control and adjust the characteristics of the ultrasonic signal transmitted through the liquid and the resulting cavitation measurement signal provided to the microcontroller 50, as well as the ability to assign or set the associated thresholds and ranges used by the microcontroller 50 to evaluate the cavitation measurement signal, allows the cavitation sensor module 10 to be configured based on the specifications of the particular liquid flow system in which the cavitation sensor module is installed. Such specifications may include, but are not limited to, the type and physical properties of the flowing liquid and the pumping flow rate or flow rate range.

[0066] like Fig. 9 As further shown in FIG. 1 , the controller board assembly 18 may include a digital output 68, an analog voltage output 72, and an analog current output 74 connected to the microcontroller 50. Additional sensors and transducers, represented at box 76, may be connected to the microcontroller 50 to enhance the functionality of the cavitation sensor module 10. Such additional sensors and transducers may include sensors and transducers for measuring or detecting pressure, temperature, flow rate, closure, and foreign debris in the flow. For example, an optical sensor may be connected to the microcontroller 50 for detecting foreign debris in the flow or other aspects of the flowing liquid. The controller board assembly 18 may also include an IO link transceiver 78 that allows data and signal communication with an external industrial network 80.

[0067] A multiplexer 53 may be implemented between the microcontroller 50 and the various outputs 68, 72, 74, and 78. Thus, two pins of a single 4-pin connector provide either: (a) up to two digital outputs, or (b) up to two analog outputs (voltage or current), or (c) an IO-Link output that is a "data" type output (not just a signal). The output type (a, b, or c) may be user configurable.

[0068] In alternative implementations of the present disclosure, the programmable microcontroller 50 may be replaced by a microprocessor, a computer, a field programmable gate array (FPGA), or even hardware-only electronics without firmware or software involved.

[0069] like Figures 2 to 4As shown, the housing 20 can be configured to enclose and protect the transducer plugs 14, 16 and the controller circuit board assembly 18 from environmental contaminants. For example, the housing 20 can be sealed to prevent liquids from entering and damaging the transducer plugs 14, 16 and the controller circuit board assembly 18. The housing 20 can include: a center piece 22A, which is sized to receive the controller circuit board assembly 18 and a first radial portion of the pipe segment 12; a cover 22B, which is removably attached to the center piece 22A and sized to cover the controller circuit board assembly 18; and a fixing piece 22C, which is removably attached to the center piece 22A and sized to receive a second radial portion of the pipe segment 12 opposite the first radial portion of the pipe segment 12 to fix the housing 20 to the pipe segment. The cover 22B can be removably attached to the center piece 22A by threaded fasteners (not shown) disposed in a plurality of aligned fastener holes 24 in the cover 22B and the center piece 22A. The fixture 22C may be removably attached to the center piece 22A by threaded fasteners (not shown) disposed in a plurality of aligned fastener holes 26 in the fixture 22C and the center piece 22A. As shown in the figures, the housing 20 may be configured such that the housing does not enclose the coupling 32 of the pipe segment 12, thereby allowing access to the coupling when the cavitation sensor module 10 is installed in a piping system.

[0070] As can be appreciated, the multi-piece configuration of the housing 20 according to the present disclosure enables the pipe segment 12 with the transducer plugs 14 and 16 to be installed in the piping system before the other components of the cavitation sensor module 10 are installed. After the pipe segment 12 with the transducer plugs 14 and 16 are installed in the piping system, the housing 20 containing the controller circuit board assembly 18 can be installed on the pipe segment 12, and the connecting wiring 19 from the ultrasonic transducers 15, 17 can be connected to the controller circuit board assembly by plugging the electrical connectors 43 into corresponding connecting sockets in the controller circuit board assembly 18. The multi-piece configuration of the housing 20 also allows the cavitation sensor module 10 (minus the pipe segment 12 and the transducer plugs 14 and 16) to be easily removed from the piping system.

[0071] In the above-described embodiments, the control electronics are mounted on a housing, for example on the pipe section 12 or on a pump housing. Figures 10 to 17An ultrasonic cavitation sensor device 110 according to another embodiment of the present disclosure is illustrated, wherein the control electronics of the device are located away from a housing having a fluid flow conduit. The ultrasonic cavitation sensor device 110 may generally include a control unit 111, a housing 112 (e.g., a pipe segment or a pump housing), and one or more first transducer plugs 14 each having a first ultrasonic transducer 15, one or more second transducer plugs 16 each having a second ultrasonic transducer 17 paired with a corresponding first ultrasonic transducer 15, and a controller circuit board assembly 118 located away from the housing 112 within a housing 120 of the control unit 111. The circuit board assembly 118 may be connected to each first ultrasonic transducer 15 and each second ultrasonic transducer 17 via a transducer cable 119. As shown in FIG. Fig.11 As shown, the circuit board assembly 118 may include a coaxial power connector 59 , an Ethernet port 55 , and a plurality of cable connectors 67 for connecting the transducer cables 119 to the circuit board assembly 118 .

[0072] Fig.12 The housing 112 is shown as a pipe segment having a liquid flow conduit 30 and a pair of female pipe couplings 32, each of which has an internal threaded portion 34 for mating with system pipes. Of course, other types of pipe segments can also be used to embody the housing 112. For example, in Fig.10 In FIG. 1 , the housing 112 is embodied by a pipe section having a pair of couplings 32 having external threads 34. FIG. 13A to FIG. 13C Examples of common pipe segment configurations that may be used as housing 112 are illustrated in FIG. Fig.13A A pipe section having a "sanitary flange" connection coupling 32 is shown. Fig. 13B Shows something like Fig.12 A pipe section having a female NPT coupling 32 in the housing 112 is provided. Fig. 13C Shows something like Fig.10 A pipe segment with a male NPT coupling 32 is provided in the housing 112 in the embodiment of the present invention. The sizing of the pipe segment can be adapted to meet the system requirements, and standard sizes can be provided to adapt to nominal pipe sizes, such as 1 inch, 1.5 inch, 2 inch, 2.5 inch and 3 inch sizes. Of course, larger or smaller sizes can be developed, and the configuration of the coupling 32 depends on the design choice. The threaded ports 38 for receiving the transducer plugs 14 and 16 can be drilled and tapped through the wall of the housing 112 so that the transducer plugs are arranged coaxially with each other across the flow conduit 30. By using standardized configurations for the transducer plugs 14 and 16 and the transducer ports 38, economies of scale and ease of design are achieved.

[0073] Fig.14 and Fig.15Another embodiment of the transducer plug 14 and 16 according to the present disclosure is illustrated. The plugs 14, 16 are hermetically sealed and very modular. It can be seen that the plugs 14, 16 include a plug housing 82 that can be machined from either plastic or metal, a carrier plate 84 that can be formed from plastic, a piezoelectric transducer element 15, 17 supported by the carrier plate 84, and a sealed connector 86 having a pair of contact members 88 connected to the transducer element 15, 17 by a pair of wires 89. In the illustrated embodiment, the connector 86 is fixed to a circular mounting plate 90 by a nut 92 and is fluid-sealed with an O-ring 94. The mounting plate 90 can be fixedly retained in the plug housing 82 by an adhesive potting 96. As can be appreciated, the transducer cable 119 can be removably connected to the connector 86 of the transducer plug 14, 16 at one end, and removably connected to the cable connector 67 on the circuit board assembly 118 at the opposite end. The plug housing 82 includes an externally threaded portion 83 that is designed to mate with the internally threaded port 38 in the housing 112 to facilitate easy installation and removal of the transducer plugs 14 , 16 .

[0074] like Fig.16 and Fig.17 As shown, the ultrasonic cavitation sensor device 110 can be modified to be mounted on a pump housing 212 of a centrifugal pump 200, wherein the pump housing 212 replaces the pipe section 112. The pump housing 212 includes an outlet liquid conduit 230 and a plurality of ports 238 extending through the wall of the pump housing for receiving and positioning the transducer plugs 14 and 16. The transducer plugs 14, 16 are threaded and have O-ring seals for high pressure fluid sealing, so the outlet of the pump housing 212 can be drilled and tapped on a common central axis to form the port 238, and the transducer plugs 14, 16 can be screwed into the port 238.

[0075] like Fig.18 and Fig.19 As shown, the ultrasonic cavitation sensor device 110 can be modified to be mounted on a valve housing 312 of a liquid flow valve 300, wherein the valve housing 312 replaces the pipe segment 112. The valve housing 312 includes a liquid conduit 330 and a plurality of ports 338 extending through the wall of the valve housing for receiving and positioning the transducer plugs 14 and 16. The transducer plugs 14, 16 are threaded and have O-ring seals for high pressure fluid sealing. The valve housing 312 can be drilled and tapped on a common central axis to form the port 338, and the transducer plugs 14, 16 can be screwed into the port 338.

[0076] exist Figure 20 to Figure 22A "clip-on" variation of the present disclosure is shown in . In the clip-on variation, the ultrasonic transducers 15, 17 can be mounted on a fixture body 400 that is configured to clamp onto an existing pipe segment or tube 412, or onto another housing in an existing liquid flow system having a liquid flow conduit 430. The clip-on variation can be used where non-invasive installation is desired, i.e., where it is impractical, unsafe, or impossible to drill and tap an existing housing to access the liquid flow conduit and install the transducer plugs 14, 16. The clip-on variation is non-invasive because the transducer plugs 14, 16 do not extend into the liquid conduit 430 through which the liquid flows.

[0077] Fig. 20 and Fig.21 A simple example for clamping onto a cylindrical pipe is depicted, the example comprising a clamp body 400 having a pair of arcuate brackets 401 and 402 designed to releasably mate with each other and tighten around a cylindrical pipe 412 within an outer diameter range. In the illustrated embodiment, the bracket 401 comprises a first flange 403 having an opening 404 therethrough and a second flange 405 having a fastener hole 406 therethrough, and the bracket 402 comprises a first flange 407 bent to define a snap sized to be removably received through the opening 404 and a second flange 408 having a fastener hole 409 therethrough. Bolts 410 may be arranged through the aligned fastener holes 406, 409 and secured with nuts 411 to adjustably tighten the clamp body 400 to the pipe 412. Each bracket 401, 402 may include an internally threaded port 38 for receiving and positioning a transducer plug 14, 16, respectively, so that when the brackets 401, 402 are fastened together, the corresponding transducers 15, 17 are axially aligned with each other across the fluid conduit 430 of the pipe 412. Fig. 20 and Fig.21 A simple clamping bracket is shown in , but other clamping configurations are of course possible, including but not limited to linear slides or spring loaded transducer housings. A transducer connection cable (not shown) may be provided to connect the transducer plugs 14, 16 to the control unit 111 as described above.

[0078] In the clamp-on variant, when the ultrasonic signal from each first ultrasonic transducer 15 travels to reach the paired second ultrasonic transducer 17, the signal must travel through the wall of the housing 412 twice. Therefore, modifications that minimize the signal attenuation effects of the housing wall may be advantageous. Good coupling of the transducers 15, 17 to the outer wall surface of the housing 412 is important. To this end, as shown in FIG. Fig. 22As best shown, each transducer plug 14, 16 may include a compliant face pad 87 on an end face of the plug housing 82. The compliant face pad 87 may be made of an elastomeric material so as to conform to the contour of the outer wall surface of the housing 412 when the clamp body 400 is fastened to the housing 412. An ultrasonic coupling containing a liquid or gel may be provided in association with each of the transducer plugs 14, 16 to assist in propagation of ultrasonic energy between each ultrasonic transducer 15, 17 and the existing housing 412 to which the transducer is clamped. The strength of the transmitted ultrasonic signal and the gain applied to the received cavitation detection signal may be increased to compensate for the attenuation of the ultrasonic signal caused by the housing wall.

[0079] exist Figure 23 to Figure 25 A bonded variant or an adhered variant of the present disclosure is shown in . In many cases, the application will have physical space or weight limitations, and the use of transducer plugs 14, 16 is not feasible. Alternatively, in some cases, it may not be desirable to have an invasive transducer plug configuration with a port 38, which may interrupt the originally smooth inner surface of the liquid conduit in the housing of a tube, fitting, or other system component. In these cases, the ultrasonic transducer system 500 can be bonded to the outer surface of the housing 512 of the component. For example, in the accompanying drawings, the housing 512 is embodied as a flow reducer fitting, in which air pockets can be generated at the transition of the inner diameter of the liquid conduit 530. The mounting area may be too small for an invasive transducer plug assembly, and if the transducer plug is installed, it itself may cause undesirable air pockets. In the bonded variant, the transducer assemblies 514 and 516 can be mounted to the outside of the fitting 512. Each transducer assembly 514, 516 may include a carrier plate 84, which may be formed of plastic, a piezoelectric transducer element 15, 17 supported by and bonded to the carrier plate 84, and a pair of wires 89 connected to the transducer elements 15, 17. A suitable mounting location may be prepared by machining a counterbore or flat surface 513 on the outer surface of the fitting 512. The carrier plate 84 of each transducer assembly 514, 516 may be bonded to the surface 513 using a suitable adhesive or bonding agent. As described above, axial alignment of the paired transducer elements 15 and 17 is desired. The wires 89 from each transducer element 15, 17 may be fed into a connecting cable (not shown) that is connected to a corresponding cable connector 67 on the control unit 111.

[0080] As can be appreciated, each of the embodiments described herein using a pair of transducers 15, 17 may be modified to operate using a single transducer operating in a pulse-echo arrangement.

[0081] See now Fig.26A and Fig.26B6 is a diagram illustrating an optional user interface display screen 600 of the ultrasonic cavitation sensor device 110. The screen 600 may be displayed on an external computing device 70 (e.g., a personal computer) and / or on a touch-sensitive display panel connected for data communication with the microcontroller 50. The use of the cavitation sensor device 110 does not require a user interface, as the sensor device may operate in a standalone configuration to provide digital output signals and / or analog output signals to a connected device. However, a user interface may be provided and used to set sensitivity parameters and general setup parameters of the sensor device 110.

[0082] User interface screen 600 enables a user to monitor the functionality of sensor device 110 and to set operating parameters of sensor device 110 . Fig.26A 6 shows display screen 600 during operation of sensor device 110 when cavitation bubbles are not present, and Fig.26B Display screen 600 is shown during operation of sensor device 110 when four groups of cavitation bubbles are present. Fig.26A and Fig.26B Snapshots of screen 600 are shown during operation of sensor device 110 , and certain portions of display screen 600 are dynamic and change as fluid flow conditions monitored by sensor device 110 change.

[0083] Screen 600 may include a signal bar graph panel 602, an average signal bar graph panel 604, an averaging slider tool 605, a tuning slider tool 606, a signal data panel 608, a status text box 610, and a cavitation alarm settings panel 611. Screen 600 may include additional interface items intended for use by factory setup technicians and service technicians, as opposed to end users of sensor device 110. These additional items of screen 600 may include a communication configuration panel 614, a tuning control panel 615 and 616, and a recording capture panel 618. It is contemplated that a limited version of screen 600 lacking additional items 614, 615, 616, and 618 is provided for the purposes of end users, and an enhanced version of screen 600 including additional items 614, 615, 616, and 618 is provided for the purposes of factory technicians and service technicians.

[0084] The signal bar graph panel 602 has a bar graph recorder 620 that shows the instantaneous intensity of the received ultrasonic signal as a function of time, and may include a slider tool 622 for setting the number of points on the X-axis (time axis) of the bar graph recorder 620. The signal intensity range is indicated on the left side of the panel (0% to 100%). If the received signal is at 100%, it indicates that there are no cavitation bubbles in the liquid between the transmitting ultrasonic transducer 15 and the paired receiving ultrasonic transducer 17. If the received signal is at 0%, it indicates that there are sufficient cavitation bubbles formed to block the transmitter-to-receiver path of the ultrasonic signal. Values ​​between 0% and 100% indicate the relative size or volume of the cavitation bubbles present in the transmitter-to-receiver path of the ultrasonic signal. The received signal strength is inversely proportional to the size of the cavitation bubbles in the transmitter-to-receiver path of the ultrasonic signal.

[0085] Average signal bar graph panel 604 is similar to signal bar graph panel 602. Average signal bar graph panel 604 has a bar graph recorder 624 that shows a smoothed average of the signal strength as a function of time, rather than the instantaneous signal strength as shown in bar graph recorder 620. This difference is shown in FIG. Fig.26B In Fig.26A The average signal bar graph panel 604 may include a slider tool 626 for setting the number of points on the X-axis (time axis) of the bar graph recorder 624. The averaging slider tool 605 sets the time interval over which the signal strength is averaged in the bar graph recorder 624.

[0086] The tuning slider tool 606 sets the time between tuning events during which the resonant frequency of the first ultrasonic transducer 15 is found for transmission at maximum signal strength. For example, a tuning event may involve a frequency sweep of the first ultrasonic transducer 15 to find the resonant frequency.

[0087] The signal data panel 608 displays instantaneous measurement data of the ultrasonic transducers 15, 17, such as received signal strength, transmitter frequency, peak voltage of the receiving transducer 17, and other measurement data. The received signal strength indicated in the signal data panel 608 is the same as the instantaneous signal strength represented in the strip chart recorder 620 at the right edge (right vertical axis) of the strip chart recorder 620.

[0088] Status text box 610 displays data recorded by sensor device 110 .

[0089] The cavitation alarm setting panel 611 includes an interface tool that enables a user to establish one or more alarm conditions for triggering the generation of a cavitation alarm signal based on characteristics of the cavitation measurement signal. The alarm condition may include a cavitation occurrence condition that is satisfied when the strength of the cavitation measurement signal drops below a cavitation alarm set point. For example, if it is determined through user observation that system damage is likely to occur when the strength of the cavitation measurement signal drops below 10%, the cavitation alarm set point may be set at 10%, such as Fig.26A and Fig.26B The cavitation alarm settings panel 611 may include a set point slider tool 628, a set point roller 630, and / or other user interface input tools through which a user may enter variable user inputs for establishing a cavitation alarm set point.

[0090] The microcontroller 50 may be programmed to register a cavitation error count corresponding to the number of consecutive times that the cavitation occurrence condition has been met, and the alarm condition may further include a cavitation error count condition that is met when the cavitation error count equals a cavitation error count setting specified by the user. As can be appreciated, the error count setting may be set to a sufficiently high value to eliminate redundant alarms. For example, in Fig.26A and Fig.26B , the cavitation error count setting is set to five, such that five consecutive events that satisfy the cavitation occurrence condition (i.e., the cavitation measurement signal drops below the cavitation alarm set point) are required to cause the output alarm. In one embodiment, the error count setting may be set to any integer value from 1 to 1000, although other ranges may be provided for the error count setting. The cavitation alarm settings panel 611 may include an error count roller 632 and / or other user interface input tools through which a user may enter variable user inputs for establishing the error count setting.

[0091] The communication configuration panel 614 includes switches for facilitating communication between the external computing device 70 and the ultrasonic transducer 15, 17 for debugging and development purposes. Switch 634 controls the transmission control protocol (TCP) so that the external computing device 70 can be selectively enabled as a host through an Ethernet connection. Switch 636 changes the operating mode of the ultrasonic transducer between a pulse transmission mode and a continuous transmission mode. Switch 638 pauses the tuning sweep for debugging purposes. Switch 640 turns tuning on and off (when tuning is off, the ultrasonic transducer operates at a static frequency).

[0092] Tuning control panels 615 and 616 enable a technician to enter other settings for development and debugging purposes. Tuning control panel 615 allows the user to change the ultrasonic transducer pulse and tuning settings. Tuning control panel 616 allows the user to adjust the tuning set point (i.e., the acceptable level for the maximum reading). This panel will not be available in the commercial version.

[0093] The record capture panel 618 allows the user to set a file name for the recorded data, set a tuning range, and enable and disable capture for the status box 642.

[0094] As described above, the communications configuration panel 514, tuning control panels 615 and 616, and recording capture panel 618 are intended for use by factory technicians and service technicians, and may be omitted from commercial versions of the user interface screen 600 available to end users.

[0095] Fig.26A The user interface screen 600 is shown when there are no cavitation bubbles. As can be seen in the strip chart recorders 620 and 624, the strength of the cavitation measurement signal remains very high. In contrast, Fig.26B The user interface screen 600 is shown when there are several cavitation bubbles. The strip chart recorders 620 and 624 show at least four large cavitation events where the instantaneous intensity of the cavitation measurement signal drops to nearly 0%. The traces of the strip chart recorders 620 and 624 are moving from right to left so that the current cavitation measurement signal intensity is on the right axis (right edge) of each graph.

[0096] The digital strength value of the current instantaneous signal is displayed in the top text box in the signal data panel 608. In this example, the signal strength is 0.0%. If the signal strength drops below the cavitation alarm set point and satisfies the cavitation error count setting entered by the user at the cavitation alarm setting panel 611, the program instructions executed by the microcontroller 50 cause the microcontroller to generate a cavitation alarm signal. The cavitation alarm signal can be sent to an external control device directly connected to the circuit board assembly 118 or connected to the circuit board assembly through the industrial network 80. For example, the cavitation alarm signal can be sent to a flow valve controller and / or a pump controller to automatically reduce or stop the flow of liquid through the conduit 130 in response to the alarm signal, thereby preventing the cavitation damage before it begins. Alternatively or in addition, the cavitation alarm signal can be sent to trigger an audible alarm device and / or a visual alarm device to warn personnel of cavitation. When the cavitation alarm signal is generated, a visual indication of the alarm signal can be provided on the user interface screen 600, such as changing the color of the top text box in the signal data panel 608 to red to show the alarm state.

[0097] The cavitation sensor module 10 and cavitation sensor device 110 of the present disclosure directly detect and measure cavitation vapor bubbles in the flowing liquid. This is different from the aforementioned indirect sensing method, which detects artifacts of cavitation, such as noise, vibration or pump behavior. Therefore, cavitation bubbles are detected before they can be heard acoustically or seen visually, thereby preventing equipment damage. In addition, cavitation can be quantified by measuring the size and / or number of bubbles present. Cavitation can be detected at very low levels, and the sensing logic is adjustable or tunable to ignore cavitation below a set level, at which cavitation is only redundant rather than destructive. Unlike some indirect cavitation sensors of the prior art, the cavitation sensor module 10 and cavitation sensor device 110 of the present disclosure are suitable for use in noisy environments. The cavitation sensor module 10 and cavitation sensor device 110 are compact and have low production costs.

[0098] The disclosed cavitation sensors and methods employed thereby find useful application in heavy industry to protect expensive pump systems from potential cavitation damage. Other applications include predictive maintenance, leak detection, and safety alarms.

[0099] Although the present disclosure describes various exemplary embodiments, the detailed description is not intended to limit the scope of the present disclosure to the particular forms set forth. The present disclosure is intended to cover such alternatives, modifications, and equivalents of the described embodiments that may be apparent to those of ordinary skill in the art.

Claims

1. An apparatus for sensing cavitation in a liquid flowing through a liquid conduit, the apparatus comprising: an ultrasonic transducer system comprising one or more ultrasonic transducers, each ultrasonic transducer being arranged in acoustic communication with the liquid flowing through the conduit; and control electronics connected to the ultrasound transducer system, the control electronics configured to drive the ultrasound transducer system to transmit ultrasound signals through fluid flowing through the catheter, wherein the ultrasound transducer system receives the ultrasound signals and generates an electronic cavitation detection signal representing the intensity of the ultrasound signals received by the ultrasound transducer system; The control electronics are further configured to process the cavitation detection signal to: i) provide a cavitation measurement signal indicating whether the ultrasound signal interacts with one or more cavitation bubbles in the fluid flowing through the conduit, ii) evaluate the cavitation measurement signal to determine whether one or more cavitation alarm conditions are met, and iii) output an alarm signal when each of the one or more cavitation alarm conditions is met.

2. The device of claim 1, further comprising a housing having the catheter, wherein each of the one or more ultrasound transducers is attached to the housing.

3. The apparatus of claim 1 , wherein the one or more ultrasonic transducers of the ultrasonic transducer system include a first ultrasonic transducer and a second ultrasonic transducer facing the first ultrasonic transducer across the catheter, wherein the control electronics are configured to drive the first ultrasonic transducer to transmit the ultrasonic signal through a fluid flowing through the catheter, and wherein the second ultrasonic transducer receives the ultrasonic signal and generates the electronic cavitation detection signal.

4. The apparatus of claim 1 , wherein the one or more ultrasonic transducers of the ultrasonic transducer system comprises a single ultrasonic transducer, wherein the control electronics are configured to drive the single ultrasonic transducer to transmit the ultrasonic signal through the fluid flowing through the conduit such that the ultrasonic signal is reflected back by the housing to the single ultrasonic transducer, and wherein the single ultrasonic transducer receives the ultrasonic signal and generates the electronic cavitation detection signal.

5. The device of claim 1, further comprising a user interface connected to the control electronics. 6 . The device according to claim 5 , wherein the user interface is configured to display the cavitation measurement signal and / or a value representing an instantaneous strength of the cavitation measurement signal.

7. The apparatus of claim 5, wherein the control electronics has a cavitation alarm set point, and the one or more cavitation alarm conditions include a cavitation occurrence condition that is satisfied when the strength of the cavitation measurement signal drops below the cavitation alarm set point.

8. The apparatus of claim 7, wherein the user interface is configured to receive a first variable user input for establishing the cavitation alarm set point.

9. The apparatus of claim 7, wherein the control electronics has a cavitation error count setting, the control electronics being configured to register a cavitation error count corresponding to a consecutive number of times the cavitation occurrence condition has been met, and the one or more cavitation alarm conditions include a cavitation error count condition that is met when the cavitation error count is equal to the cavitation error count setting.

10. The apparatus of claim 9, wherein the user interface is configured to receive a second variable user input for establishing the cavitation error count setting.

11. The apparatus of claim 1 , wherein the control electronics are located remotely from the housing.

12. The apparatus of claim 1, wherein the control electronics are mounted on the housing.

13. The apparatus of claim 1, wherein the housing is selected from the group consisting of a pipe segment, a pump housing, a valve housing, and a flow reducer.

14. A method for sensing cavitation in a liquid flowing through a conduit, the method comprising the steps of: placing a first ultrasonic transducer in acoustic communication with the liquid flowing through the conduit; placing a second ultrasonic transducer in acoustic communication with the liquid flowing through the conduit, wherein the second ultrasonic transducer faces the first ultrasonic transducer across the conduit; driving the first ultrasonic transducer to transmit an ultrasonic signal through the fluid flowing through the conduit; receiving the ultrasonic signal by the second ultrasonic transducer; generating an electron cavitation detection signal by the second ultrasonic transducer, wherein the electron cavitation detection signal indicates the intensity of the ultrasonic signal received by the second ultrasonic transducer; processing the cavitation detection signal to provide a cavitation measurement signal indicating whether the ultrasound signal interacted with one or more cavitation bubbles in a fluid flowing through the conduit; evaluating the cavitation measurement signal to determine whether one or more cavitation alarm conditions are met; as well as An alarm signal is output when each of the one or more cavitation alarm conditions is satisfied.

15. The method according to claim 14, further comprising the step of displaying the cavitation measurement signal and / or a value representing the instantaneous strength of the cavitation measurement signal.

16. The method of claim 15, wherein the one or more cavitation alarm conditions include a cavitation occurrence condition, and wherein the step of evaluating the cavitation measurement signal includes comparing the strength of the cavitation measurement signal to a predetermined cavitation alarm set point, and determining that the cavitation occurrence condition is satisfied when the strength of the cavitation measurement signal drops below the cavitation alarm set point.

17. The apparatus of claim 16, wherein the one or more cavitation alarm conditions include a cavitation error count condition, and wherein the step of evaluating the cavitation measurement signal includes registering a cavitation error count corresponding to a consecutive number of times the cavitation occurrence condition has been met, and determining that the cavitation error count condition is met when the cavitation error count is equal to a predetermined cavitation error count setting.

Images