An active control method for reducing pipeline noise

Abstract

An active control method for reducing pipeline noise includes a silencer and a hydrophone on the pipeline. The silencer includes a magnetostrictive actuator, with a displacement amplification device connected to the vibrating head of the actuator. A piston is installed at the end of the displacement amplification device. When the magnetostrictive actuator is energized, the vibrating head reciprocates. The amplitude of the piston is greater than that of the vibrating head, and the reciprocating motion of the piston eliminates the primary sound wave generated by the water pump. The method also includes noise information acquisition, noise information feedback, and secondary sound wave adjustment. A current adjustment device adjusts the current driving the magnetostrictive actuator according to the initial current parameters, sets the secondary sound wave corresponding to the primary sound wave, and adjusts the current used to drive the magnetostrictive actuator so that the real-time sound pressure and real-time frequency collected by the hydrophone change to the noise control parameter level. Thus, the silencer parameters are constantly controlled according to the changes in pipeline noise when the water pump operation changes, achieving precise noise reduction.

Description

Technical Field

[0001] This invention relates to the technical field of noise reduction methods for water pipelines, and in particular to an active control method for reducing pipeline noise. Background Technology

[0002] Vibration and noise in water pipeline systems are common problems that have a certain impact on the surrounding environment. The low-frequency line spectrum noise of marine pipelines mainly originates from the shaft frequency of the water pump, with a sound pressure level typically around 170-180 dB and a frequency as low as 25 Hz. The sound pressure and frequency of the pipeline noise are related to the pump speed.

[0003] When the operation of the water pump in the water system changes, the vibration frequency and sound pressure of the traditional passive silencer are fixed and cannot be adjusted. It can only silence a single line spectrum of noise. Therefore, it is necessary to find a silencer method that can control the silencer parameters according to the changes in the noise in the pipe. Summary of the Invention

[0004] To address the shortcomings of existing production technologies, the applicant provides an active control method for silencing pipeline noise. This method allows for precise noise reduction by continuously controlling the silencer parameters based on changes in pipeline noise as the pump's operating conditions change.

[0005] The technical solution adopted in this invention is as follows:

[0006] An active control method for reducing pipeline noise includes a silencer installed on a pipeline on one side of a water pump, and a hydrophone installed on the pipeline between the silencer and the water pump.

[0007] The silencer includes a magnetostrictive actuator and a displacement amplification device mounted on the magnetostrictive actuator. The vibrating head of the magnetostrictive actuator is connected to the displacement amplification device. A piston is installed at the end of the displacement amplification device. When the magnetostrictive actuator is energized, the vibrating head reciprocates. The displacement amplification device transmits the vibration of the vibrating head to the piston and makes the amplitude of the piston greater than the amplitude of the vibrating head. The reciprocating motion of the piston generates secondary sound waves in the pipeline. The secondary sound waves are used to eliminate the primary sound waves generated by the water pump.

[0008] The noise reduction method includes the following steps:

[0009] Noise information collection:

[0010] When the water pump operates alone, the hydrophone collects the primary sound pressure and frequency of the primary sound wave generated by the pump.

[0011] When the water pump and silencer are working, the hydrophone collects the real-time sound pressure and real-time frequency of the noise in the pipeline.

[0012] Noise feedback:

[0013] The hydrophone feeds back the primary sound pressure and primary sound frequency from the noise information acquisition step to the control system, and the control system feeds back the initial current parameters to the current regulating device.

[0014] The hydrophone feeds back the real-time sound pressure and real-time frequency of noise from the noise information acquisition step to the control system. The control system compares the real-time sound pressure and real-time frequency of noise with the noise control parameters and feeds back the current adjustment parameters to the current adjustment device.

[0015] Secondary acoustic modulation:

[0016] The current regulating device adjusts the current used to drive the magnetostrictive actuator according to the initial current parameters, and is used to set the secondary sound wave corresponding to the primary sound wave.

[0017] The current regulating device adjusts the current used to drive the super magnetostrictive actuator according to the current regulating parameters, so that the real-time sound pressure and real-time frequency collected by the hydrophone change to the noise control parameter level.

[0018] Its further technical solution lies in:

[0019] The noise control parameters are the noise levels in the pipeline when the silencer and water pump are working simultaneously, including the noise sound pressure level and the noise frequency.

[0020] The initial current parameters include current magnitude and current frequency, and the current adjustment parameters include changes in current magnitude and current frequency.

[0021] The current regulating device is a power amplifier.

[0022] The structure of the super magnetostrictive actuator is as follows:

[0023] The device includes a cup-shaped outer shell, in which a giant magnetostrictive rod is installed in the center. The length direction of the giant magnetostrictive rod is consistent with the depth direction of the outer shell. A coil is wrapped around the giant magnetostrictive rod. The coil is connected to an external power source through a wire. The current through the coil and the wire is the current used to drive the giant magnetostrictive actuator.

[0024] The coil is surrounded by a ring-shaped permanent magnet. The outer ring of the permanent magnet is fitted with the inner wall of the outer shell. The upper end face of the permanent magnet is closed by an upper magnetic conductor disposed inside the outer shell, and the lower end face of the permanent magnet is closed by a lower magnetic conductor disposed at the bottom of the outer shell. The super magnetostrictive rod is located between the upper and lower magnetic conductors. A magnetic post is installed at the upper end of the super magnetostrictive rod. The upper end of the magnetic post passes through the upper magnetic conductor and is then fitted with an actuating rod. The axes of the actuating rod, the magnetic post, and the super magnetostrictive rod coincide.

[0025] The upper end of the actuating rod is a vibrating head.

[0026] A top cover is installed on the upper end of the outer shell, and a hole is opened in the middle of the top cover and a preload nut is installed thereon;

[0027] It also includes a floating seat installed on the upper end of the magnetic column, the lower end of the actuating rod is connected to the middle part of the floating seat, the vibrating head passes through the preload nut and is located above the preload nut, the middle part of the actuating rod is sealed and slidably engaged with the preload nut, a disc spring is fitted on the actuating rod between the preload nut and the floating seat, the preload nut and the floating seat are respectively engaged with the two ends of the disc spring, and the disc spring is in a compressed deformation state.

[0028] It also includes an annular diaphragm located between the top cover and the upper magnetic conductor, the inner ring of the annular diaphragm being fixedly connected to the floating seat, the outer ring of the floating seat being fixedly connected to the inner sidewall of the outer shell, and the axis of the annular diaphragm coinciding with the axis of the actuating rod.

[0029] The bottom of the outer casing is a bottom cover that is detachably connected to the side wall of the outer casing;

[0030] A heat dissipation pipe is provided between the magnetostrictive rod and the coil.

[0031] The structure of the heat dissipation pipe is as follows: it includes a cylindrical body with an annular cross-section. The central hole of the cylindrical body mates with the outer peripheral surface of the magnetostrictive rod. The cylindrical body is provided with multiple through holes, which are arranged in a ring array around the central hole of the cylindrical body. The axes of the multiple through holes are parallel to the axis of the cylindrical body. The lower ports of two adjacent through holes are respectively the cooling water inlet and the cooling water outlet. Multiple elongated grooves are provided at both ends of the cylindrical body. After the two ends of the cylindrical body are sealed with the upper and lower magnetic conductors, the elongated grooves connect the multiple through holes to form a complete flow path. The cooling water inlet and the cooling water outlet are connected to the water inlet channel and the water outlet channel on the bottom cover through two perforations located on the lower magnetic conductor, respectively. The water inlet channel and the water outlet channel are connected to the water supply system.

[0032] The structure of the displacement amplification device is as follows:

[0033] The device includes a cavity, which is a tubular structure. One end of the cavity is sealed to an interface on a pipeline, allowing the interior of the cavity to communicate with the pipeline. The other end of the cavity is connected to the magnetostrictive actuator.

[0034] The cavity is equipped with an enlarged structure.

[0035] The enlarged structure includes a first bellows and a second bellows arranged coaxially. The cross-sectional area of ​​the first bellows is smaller than that of the second bellows. The lower end face of the first bellows is connected to the upper end face of the second bellows through a connecting plate. The upper end face of the first bellows is sealed by a top plate, and the lower end face of the second bellows is sealed by a bottom plate. The inner cavities of the first bellows and the second bellows are connected and filled with hydraulic oil. An oil injection hole is provided on the bottom plate. A mounting base is provided on the inner wall of the cavity. The outer periphery of the connecting plate is detachably mounted on the mounting base.

[0036] The base plate is connected to the vibrating head, and the piston is installed on the top plate.

[0037] A third bellows is provided outside the first bellows. The third bellows is coaxially arranged with the first bellows. The upper end of the third bellows is sealed to the lower part of the piston, and the lower end of the third bellows is sealed to the connecting plate. Air is injected between the first bellows and the third bellows. An air inlet is provided on the piston for air injection.

[0038] The beneficial effects of this invention are as follows:

[0039] This invention features a compact and rational structure, and is easy to operate. It employs a magnetostrictive actuator for active control of the silencer on the pipeline, and indirectly drives a piston to generate secondary sound waves via a displacement amplification device. Noise within the pipeline is fed back to the control system via a hydrophone. A current regulating device controls the driving current of the magnetostrictive actuator, thereby adjusting the sound pressure and frequency of the secondary sound waves to match the primary sound waves to be eliminated. This allows for active noise elimination of the pipeline even when the pump's operating conditions change, with a fast response speed. The silencer parameters can be continuously controlled based on changes in pipeline noise, achieving precise noise reduction.

[0040] Furthermore, the present invention also has the following advantages:

[0041] (1) In the super magnetostrictive actuator, the combination of coil and super magnetostrictive rod can control the length of super magnetostrictive rod through magnetic field, thereby controlling the output force or displacement signal. This device has fast response speed, large force, high accuracy and stability, and can accurately output secondary sound waves with specific sound pressure and frequency.

[0042] (2) By using the pre-tightening nut, floating seat and disc spring cooperation structure, the disc spring in the compressed state applies pre-compression stress to the super magnetostrictive rod, so as to avoid the super magnetostrictive rod from generating excessive tensile stress during the operation and ensure the stable displacement output of the super magnetostrictive rod.

[0043] (3) The annular diaphragm limits the radial position of the floating seat. On the one hand, it ensures that the movement direction of the actuator rod installed on the floating seat is not eccentric in the axial direction, so that the displacement output by the actuator rod is consistent with the deformation of the super magnetostrictive rod. On the other hand, it maintains the gap between the magnetic column and the upper magnetic body to avoid friction between the two affecting the output characteristics of the actuator.

[0044] (4) After the cooling water from the water supply system enters through the inlet channel, it flows through the flow path formed by the through holes and then flows out through the outlet channel. The cooling water flow path of the heat dissipation pipe, which is connected by multiple through holes to form a flow path, is long and evenly distributed on the outer periphery of the giant magnetostrictive rod. It has a good heat exchange effect and ensures the stability of the working state of the giant magnetostrictive rod.

[0045] (5) By setting two bellows with different cross sections and filling the cavity formed by the two bellows with hydraulic oil, the change of the volume of a single bellows is converted into a change of displacement. The amplitude of the vibrating head connected to the large cross section bellows is amplified and the piston outputs the secondary sound wave that meets the requirements.

[0046] (6) By setting a third bellows outside the first bellows, the contact area between the piston and the enlarged structure is increased, making the piston movement more stable and the piston plane perpendicular to the direction of movement. Compressible air is filled between the first bellows and the third bellows, which makes the third bellows deform better and play a buffering role, making the piston movement more stable and less affected by the medium. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the present invention.

[0048] Figure 2 This is a schematic diagram of the silencer of the present invention.

[0049] Figure 3 This is an exploded view of the muffler of the present invention.

[0050] Figure 4 This is a cross-sectional view of the muffler of the present invention.

[0051] Figure 5 This is an isometric sectional view of the super magnetostrictive actuator of the present invention.

[0052] Figure 6 This is a schematic diagram of the assembly of the heat dissipation pipe of the present invention.

[0053] Figure 7This is a schematic diagram of the heat dissipation pipe of the present invention.

[0054] Figure 8 This is a schematic diagram of the heat pipe structure of the present invention (from another perspective).

[0055] Figure 9 This is an isometric sectional view (including the piston) of the displacement amplification device of the present invention.

[0056] Figure 10 This is an exploded view (including the piston) of the displacement amplification device of the present invention.

[0057] Figure 11 This is an exploded view (including the piston, from another perspective) of the displacement amplification device of the present invention.

[0058] Among them: a) piping; b) silencer; c) hydrophone; d) control system; e) current regulating device; f) charge amplifier;

[0059] 1. Magnetostrictive actuator; 10. Vibrating head; 11. Actuating rod; 12. Disc spring; 121. Preload nut; 122. Floating seat; 123. Annular diaphragm; 13. Upper magnetic conductor; 131. Magnetic column; 14. Magnetostrictive rod; 15. Heat sink; 150. Columnar body; 151. Through hole; 152. Cooling water inlet; 153. Cooling water outlet; 16. Coil; 17. Permanent magnet; 18. Lower magnetic conductor; 19. Outer shell; 191. Bottom cover; 192. Top cover; 193. Water inlet channel; 194. Water outlet channel;

[0060] 2. Displacement amplification device; 20. Top plate; 21. Cavity; 211. Mounting base; 22. Third bellows; 23. First bellows; 24. Connecting plate; 25. Second bellows; 26. Base plate; 261. Oil injection hole; 3. Piston; 31. Air inlet. Detailed Implementation

[0061] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0062] like Figures 1-4 As shown, the active control method for reducing pipeline noise in this embodiment includes a silencer b installed on pipeline a on one side of the water pump, and a hydrophone c installed on pipeline a between the silencer b and the water pump.

[0063] The silencer b includes a magnetostrictive actuator 1 and a displacement amplification device 2 mounted on the magnetostrictive actuator 1. The vibrating head 10 of the magnetostrictive actuator 1 is connected to the displacement amplification device 2. A piston 3 is mounted at the end of the displacement amplification device 2. When the magnetostrictive actuator 1 is powered on, the vibrating head 10 reciprocates. The displacement amplification device 2 transmits the vibration of the vibrating head 10 to the piston 3 and makes the amplitude of the piston 3 greater than the amplitude of the vibrating head 10. The reciprocating motion of the piston 3 generates secondary sound waves in the pipeline a. The secondary sound waves are used to eliminate the primary sound waves generated by the water pump.

[0064] Low-frequency line spectrum noise in marine pipelines mainly originates from the shaft frequency of the water pumps. The primary sound pressure level of the pumps within the pipeline is typically around 170–180 dB, with frequencies as low as 25 Hz. Both the primary sound pressure level and frequency are related to the pump's rotational speed. Secondary sound waves have comparable intensity to the primary sound waves; both must have the same frequency but opposite amplitude to eliminate the primary sound waves. Due to the relatively high characteristic impedance of water, a large current is required.

[0065] The magnetostrictive actuator 1, which uses the magnetostrictive rod 14 as the actuating component, serves as the main actuator of the muffler b. In the design process of the actuator, the maximum output displacement and actuating force required by the actuator are first calculated based on the theory of sound propagation in pipelines. Then, the magnetostrictive rod 14 and key components such as the coil 16 that generates the bias magnetic field are designed based on electromagnetic theory. Finally, the magnetic field is verified using finite element numerical calculation software.

[0066] The changes in the magnitude and frequency of the current driving the magnetostrictive actuator 1 can cause changes in the movement of the vibrating head 10. The displacement of the magnetostrictive actuator 1 is relatively small, and the displacement generated by directly driving the piston 3 is too small to effectively eliminate the primary sound waves produced by the water pump. The complete structure of the silencer b includes the magnetostrictive actuator 1 and an acoustic emission section. The acoustic emission section amplifies the amplitude of the vibrating head 10 of the magnetostrictive actuator 1 through the displacement amplification device 2, increasing the position of the piston 3 while simultaneously matching the frequency of the vibrating head 10. The piston 3 then generates secondary sound waves that meet the silencing requirements.

[0067] Specifically, silencer b is installed on the side of the pipe at the pump inlet or outlet. Hydrophone c is used to measure the sound pressure and frequency of noise in pipe a. A Danish B&K 8103 miniature hydrophone can be used to guide how to adjust the current of the magnetostrictive actuator 1. When silencer b is working, it provides feedback on the noise reduction effect. If the noise reduction effect is not obvious, it indicates that the sound pressure and frequency of the secondary sound wave generated by silencer b need to be actively adjusted.

[0068] The expression for a secondary sound wave can be written as: P = Asin(ωt), which means that the secondary sound wave P is determined by two parameters: amplitude A and frequency ω, where t is the time variable.

[0069] Furthermore, the primary sound wave frequency generated by the water pump is related to the pump's rotational speed. The primary sound wave frequency = rotational speed / 60. For example, when the pump's rotational speed is 3000 rpm, the corresponding primary sound wave frequency is 3000 / 60 = 50 Hz. Therefore, it is necessary to adjust the current frequency of the magnetostrictive actuator 1 to make the reciprocating motion frequency of the vibrating head 10 consistent with the primary sound source frequency of the water pump, thus ensuring the secondary sound wave frequency matches the primary sound wave frequency. The primary sound wave pressure generated by the water pump is also related to the pump's rotational speed. The faster the pump rotates, the louder the sound, and the greater the primary sound wave pressure and amplitude. Therefore, when the pump's rotational speed changes, it is often necessary to change the secondary sound wave pressure to make it consistent with the primary sound wave pressure. This change in secondary sound wave pressure is achieved by adjusting the amplitude of the piston 3. When the current of the magnetostrictive actuator 1 is increased or decreased, the amplitude of the vibrating head 10 changes, which in turn drives the amplitude of the piston 3 to change, thus achieving the purpose of adjusting the secondary sound wave pressure.

[0070] The noise reduction method includes the following steps:

[0071] Noise information collection:

[0072] When the water pump operates alone, hydrophone C collects the primary sound pressure and frequency of the primary sound wave generated by the water pump.

[0073] When the water pump and silencer b are working, the hydrophone c collects the real-time sound pressure and real-time frequency of the noise in the pipeline a.

[0074] Noise feedback:

[0075] Hydrophone c feeds back the primary sound pressure and primary sound frequency from the noise information acquisition step to control system d, and control system d feeds back the initial current parameters to current regulating device e.

[0076] Hydrophone c feeds back the real-time sound pressure and real-time frequency of noise from the noise information acquisition step to the control system d. The control system d compares the real-time sound pressure and real-time frequency of noise with the noise control parameters and feeds back the current adjustment parameters to the current adjustment device e.

[0077] The noise control parameters are the noise levels in pipeline a when silencer b and water pump are working simultaneously, including noise sound pressure value and noise frequency value, which are used to detect whether the noise reduction effect meets the requirements.

[0078] The initial current parameters include current magnitude and current frequency, and the current adjustment parameters include changes in current magnitude and current frequency.

[0079] Secondary acoustic modulation:

[0080] The current regulating device e adjusts the current used to drive the magnetostrictive actuator 1 according to the initial current parameters, and is used to set the secondary sound wave corresponding to the primary sound wave.

[0081] The current regulating device e adjusts the current used to drive the super magnetostrictive actuator 1 according to the current regulating parameters, so that the real-time sound pressure and real-time frequency collected by the hydrophone c change to the noise control parameter level.

[0082] Specifically, the current regulating device e is a power amplifier used to regulate the magnitude and frequency of the current driving the super magnetostrictive actuator 1, and a power amplifier of model YE5872A can be used; the hydrophone c is connected to the control system d through the charge amplifier f, and a Danish B&K2692-A type charge amplifier corresponding to the hydrophone c can be used; the control system d is a computer or other processor, and the control system d can set relevant parameters, such as initial current parameters, noise control parameters, and current regulation parameters.

[0083] The initial current parameters are used to ensure that the primary sound wave pressure and secondary sound wave pressure and frequency are consistent. These parameters can be used to determine the current magnitude and frequency during the initial commissioning of the silencer b. When the silencer b and the water pump are working simultaneously, the water pump speed changes, and the noise pressure and frequency values ​​do not meet the requirements. The control system d obtains the corresponding secondary sound wave pressure and frequency that need to be updated based on the real-time noise pressure and frequency, and then obtains the current magnitude and frequency that need to be adjusted, and feeds them back to the current regulating device e.

[0084] The silencer b on pipeline a is actively controlled by a magnetostrictive actuator 1, and indirectly drives the piston 3 through a displacement amplification device 2 to generate secondary sound waves. The noise in pipeline a is fed back to the control system d through a hydrophone c. The driving current of the magnetostrictive actuator 1 is controlled by a current regulating device e, thereby adjusting the sound pressure and frequency of the secondary sound waves to match the primary sound waves to be eliminated. When the operation of the water pump changes, the noise in the pipeline is actively eliminated, and the response speed is fast. The silencer parameters can be controlled in real time according to the changes in pipeline noise to achieve precise noise reduction.

[0085] like Figures 4-5 As shown, the structure of the supermagnetostrictive actuator 1 is as follows:

[0086] The device includes a cup-shaped outer shell 19, with a giant magnetostrictive rod 14 installed in the center of the inner part of the outer shell 19. The length direction of the giant magnetostrictive rod 14 is consistent with the depth direction of the outer shell 19. A coil 16 is sleeved on the outside of the giant magnetostrictive rod 14. The coil 16 is connected to an external power source through a wire. The current through the coil 16 and the wire is the current used to drive the giant magnetostrictive actuator 1. The wire is connected to a charge amplifier f.

[0087] A ring-shaped permanent magnet 17 is sleeved around the coil 16. The outer ring of the permanent magnet 17 is fitted with the inner wall of the outer shell 19. The upper end face of the permanent magnet 17 is closed by an upper magnetic conductor 13 disposed inside the outer shell 19. The lower end face of the permanent magnet 17 is closed by a lower magnetic conductor 18 disposed at the bottom of the outer shell 19. A super magnetostrictive rod 14 is located between the upper magnetic conductor 13 and the lower magnetic conductor 18. A magnetic guide post 131 is installed at the upper end of the super magnetostrictive rod 14. The upper end of the magnetic guide post 131 passes through the upper magnetic conductor 13 and is then fitted with an actuating rod 11. The axes of the actuating rod 11, the magnetic guide post 131 and the super magnetostrictive rod 14 are coincident. The upper end of the actuating rod 11 is a vibrating head 10.

[0088] Specifically, the ring-shaped permanent magnet 17 is composed of multiple ring structures arranged side by side along the axial direction. The super magnetostrictive rod 14 is supported by the bottom of the outer shell 19, i.e., the bottom cover 191. The output displacement is transmitted to the actuating rod 11 through the magnetic column 131. Since the super magnetostrictive actuator 1 is used for pipe a, a top cover 192 is installed on the upper end of the outer shell 19, so that the vibrating head 10 extends out of the top cover 192. At the same time, a sealing ring that seals with the top cover 192 is installed on the actuating rod 11 to keep the top cover 192 watertight and withstand a certain back pressure. The upper magnetic column 13 is provided with a through hole for the magnetic column 131 to pass through, and there is a certain gap between the magnetic column 131 and the through hole.

[0089] The permanent magnet 17 is made of a material capable of generating a constant magnetic field, typically composed of magnetic materials such as iron, cobalt, nickel, and their alloys. The direction of the magnetic field of the permanent magnet 17 can also be set as needed. After magnetic field polarization treatment, the permanent magnet 17 can generate a constant magnetic field without requiring an external power supply.

[0090] The upper magnetic conductor 13 and the lower magnetic conductor 18 are materials capable of forcing a magnetic field to move in a predetermined direction. They are also typically made of magnetic materials such as iron, cobalt, nickel, and their alloys. In electric motors and generators, magnetic conductors are commonly used as electromagnet coils to generate and control the direction and intensity of the magnetic field.

[0091] The combination of the ring-shaped permanent magnet 17, the upper magnetic conductor 13, and the lower magnetic conductor 18 ensures that the magnetic field moves along a predetermined direction and generates a changing magnetic field with a predetermined pattern within the magnetic conductor. This changing magnetic field can cause the motor to move or the generator to produce electricity, thus realizing the conversion and transfer of energy.

[0092] Coil 16 and super magnetostrictive rod 14 are magnetostrictive devices, wherein:

[0093] The coil 16 is usually made of wire wound into a ring or other shape. The current in the coil 16 is alternating current, which forms a magnetic field with changing direction around the giant magnetostrictive rod 14. This magnetic field causes the giant magnetostrictive rod 14 to expand and contract, thereby converting the electrical signal into force or displacement output.

[0094] The giant magnetostrictive rod 14 is a special magnetic material that can undergo magnetostriction under the influence of a magnetic field. When the direction of the magnetic field changes in the giant magnetostrictive rod 14, the length of the giant magnetostrictive rod 14 also changes. Therefore, the giant magnetostrictive rod 14 converts electrical signals into force or displacement output.

[0095] In the magnetostrictive actuator 1, the combination of coil 16 and magnetostrictive rod 14 can control the length of magnetostrictive rod 14 through magnetic field, thereby controlling the output force or displacement signal. This device has fast response speed, large force, high accuracy and stability, and can accurately output secondary sound waves with specific sound pressure and frequency.

[0096] The super magnetostrictive actuator 1 is a servo system made using the principles of hysteresis, hysteresis-scaling effect and electromagnetism, which can convert electrical signals into force or displacement output.

[0097] like Figures 4-5 As shown, a top cover 192 is installed on the upper end of the outer casing 19, and a preload nut 121 is installed in the middle of the top cover 192; it also includes a floating seat 122 installed on the upper end of the magnetic column 131, the lower end of the actuating rod 11 is connected to the middle of the floating seat 122, the vibrating head 10 passes through the preload nut 121 and is located above the preload nut 121, the middle of the actuating rod 11 is sealed and slidably engaged with the preload nut 121, a disc spring 12 is fitted on the actuating rod 11 between the preload nut 121 and the floating seat 122, the preload nut 121 and the floating seat 122 are respectively engaged with the two ends of the disc spring 12, and the disc spring 12 is in a compressed deformation state.

[0098] Specifically, the floating seat 122 is suspended under the support of the magnetic column 131; the outer circumferential surface of the preload nut 121 is threadedly connected to the opening in the middle of the top cover 192, and the compression state of the disc spring 12 can be adjusted by rotating the preload nut 121; the floating seat 122, the upper end of the floating seat 122 and the lower part of the actuating rod 11 are relatively fixedly connected; through the cooperation structure of the preload nut 121, the floating seat 122 and the disc spring 12, the compressed disc spring 12 applies preload stress to the super magnetostrictive rod 14, so as to avoid the super magnetostrictive rod 14 from generating excessive tensile stress during operation and ensure the stable displacement output of the super magnetostrictive rod 14.

[0099] like Figures 4-5 As shown, it also includes an annular diaphragm 123 located between the top cover 192 and the upper magnetic conductor 13. The inner ring of the annular diaphragm 123 is fixedly connected to the floating seat 122, and the outer ring of the floating seat 122 is fixedly connected to the inner side wall of the outer shell 19. The axis of the annular diaphragm 123 coincides with the axis of the actuating rod 11.

[0100] Specifically, the annular diaphragm 123 is a sheet-like element with axial elastic deformation.

[0101] The annular diaphragm 123 limits the radial position of the floating seat 122. On the one hand, it ensures that the movement direction of the actuating rod 11 installed on the floating seat 122 remains axially aligned, so that the displacement output by the actuating rod 11 is consistent with the deformation of the super magnetostrictive rod 14. On the other hand, it maintains the gap between the magnetic column 131 and the upper magnetic body 13 to avoid friction between them affecting the actuator output characteristics.

[0102] like Figures 5-8 As shown, the bottom of the outer casing 19 is a bottom cover 191 that is detachably connected to the side wall of the outer casing 19;

[0103] A heat dissipation pipe 15 is provided between the super magnetostrictive rod 14 and the coil 16.

[0104] The structure of the heat pipe 15 is as follows: it includes a cylindrical body 150 with an annular cross-section. The central hole of the cylindrical body 150 mates with the outer peripheral surface of the magnetostrictive rod 14. The cylindrical body 150 is provided with multiple through holes 151, which are arranged in a ring array around the central hole of the cylindrical body 150. The axes of the multiple through holes 151 are parallel to the axis of the cylindrical body 150. The lower ends of two adjacent through holes 151 are respectively the cooling water inlet 152 and the cooling water outlet 153. Multiple elongated grooves are provided at both ends of the columnar body 150. After the two ends of the columnar body 150 are sealed and fitted with the upper magnetic conductor 13 and the lower magnetic conductor 18 respectively, the elongated grooves connect the multiple through holes 151 to form a complete flow path. The cooling water inlet 152 and the cooling water outlet 153 are connected to the water inlet channel 193 and the water outlet channel 194 on the bottom cover 191 through two through holes located on the lower magnetic conductor 18 respectively. The water inlet channel 193 and the water outlet channel 194 are connected to the water supply system.

[0105] Specifically, cooling water from the water supply system enters through the inlet channel 193, flows through the flow path formed by the through holes 151, and then flows out through the outlet channel 194. The cooling water flow path of the heat dissipation pipe 15, which is formed by multiple through holes 151 connected to form a flow path, is long and evenly distributed around the outer periphery of the giant magnetostrictive rod 14, resulting in good heat exchange and ensuring the stability of the working state of the giant magnetostrictive rod 14. The heat dissipation pipe 15 is located on the axis of the coil 16. In order to control the temperature rise of the permanent magnet 17, a gap is left between the coil 16 and the permanent magnet 17, which can be used to place heat insulation material.

[0106] like Figures 9-11 As shown, the structure of the displacement amplification device 2 is as follows:

[0107] It includes a cavity 21, which is a tubular structure. One end of the cavity 21 is sealed to the interface on the pipeline a, so that the inside of the cavity 21 is connected to the pipeline a. The other end of the cavity 21 is connected to the super magnetostrictive actuator 1. An enlarged structure is provided inside the cavity 21.

[0108] The enlarged structure includes a first bellows 23 and a second bellows 25 arranged coaxially. The cross-sectional area of ​​the first bellows 23 is smaller than that of the second bellows 25. The lower end face of the first bellows 23 is connected to the upper end face of the second bellows 25 through a connecting plate 24. The upper end face of the first bellows 23 is sealed by a top plate 20, and the lower end face of the second bellows 25 is sealed by a bottom plate 26. The inner cavities of the first bellows 23 and the second bellows 25 are connected and filled with hydraulic oil. An oil injection hole 261 is provided on the bottom plate 26. A mounting seat 211 is provided on the inner wall of the cavity 21. The outer periphery of the connecting plate 24 is detachably installed on the mounting seat 211. The bottom plate 26 is connected to the vibrating head 10, and a piston 3 is installed on the top plate 20.

[0109] Specifically, the cross-sectional area of ​​the first corrugated pipe 23 generally differs significantly from that of the second corrugated pipe 25. The ratio of the cross-sectional area of ​​the second corrugated pipe 25 to that of the first corrugated pipe 23 can be 10 to 30 times. Figure 9 As shown, the inner diameter of the first bellows 23 is one-fifth of the inner diameter of the second bellows 25, that is, the cross-sectional area of ​​the second bellows 25 is twenty-five times the cross-sectional area of ​​the first bellows 23. When the base plate 26 reciprocates with the vibrating head 10, the length of the second bellows 25 changes regularly with the vibrating head 10 because the connecting plate 24 is installed on the mounting base 211. Since the hydraulic oil filled in the inner cavity of the first bellows 23 and the second bellows 25 is incompressible, the first bellows 23 will shorten synchronously with the length of the second bellows 25, or lengthen synchronously with the length of the second bellows 25, thereby driving the piston 3 installed on the top plate 20 of the first bellows 23 to reciprocate. When the cross-sectional area of ​​the second bellows 25 is twenty-five times the cross-sectional area of ​​the first bellows 23, the amplitude of the piston 3 is twenty-five times the amplitude of the vibrating head 10, so that the secondary sound wave generated by the silencer b meets the noise reduction requirements.

[0110] By setting two bellows with different cross sections and filling the cavity formed by the two bellows with hydraulic oil, the change in the volume of a single bellows is converted into a change in displacement. The amplitude of the vibrating head 10 connected to the large-section bellows is amplified and then output by the piston 3 to produce a secondary sound wave that meets the requirements.

[0111] like Figures 9-11 As shown, a third bellows 22 is provided outside the first bellows 23. The third bellows 22 is coaxially arranged with the first bellows 23. The upper end of the third bellows 22 is sealed to the lower part of the piston 3, and the lower end of the third bellows 22 is sealed to the connecting plate 24. Air is filled between the first bellows 23 and the third bellows 22. An air inlet 31 for air filling is provided on the piston 3.

[0112] By setting a third bellows 22 outside the first bellows 23, the contact area between the piston 3 and the enlarged structure is increased, making the piston 3 move more stably and the piston plane perpendicular to the direction of movement. Compressible air is filled between the first bellows 23 and the third bellows 22, which makes the third bellows 22 deform better and play a buffering role, making the movement of the piston 3 more stable and less affected by the medium.

[0113] The displacement amplification device 2 in this embodiment mainly consists of three metal bellows. The actuating rod 11 directly drives the second bellows 25, causing the hydraulic oil inside the second bellows 25 to flow to the first bellows 23, which in turn drives the piston 3 connected to one end of the first bellows 23 to move axially. Due to the difference in cross-sectional area between the two bellows, the displacement of the piston 3 relative to the displacement of the actuating rod 11 is amplified. The amplification factor is the ratio of the cross-sectional area of ​​the second bellows 25 to that of the first bellows 23. Factors such as the elasticity of the bellows themselves and the compressibility of the oil can be ignored.

[0114] The function of the third bellows 22 is to maintain a closed space together with the piston 3, thereby increasing the area of ​​the piston 3 and enabling it to reciprocate smoothly, converting the displacement of the piston 3 into an external volumetric sound source. The space between the first bellows 23 and the third bellows 22 is filled with air, and the gas, together with the first bellows 23, provides the piston 3 with elastic restoring force and a larger range of motion.

[0115] Unlike dipole sound sources generated by driving a single flange in water, this sound source consists of three bellows and a flange, forming a monopole sound source. On the one hand, this sound source can achieve micro-displacement amplification; on the other hand, it has higher sound radiation efficiency at low frequencies.

[0116] One end of the cavity 21 of the displacement amplification device 2 is sealed to the interface on the pipeline a. The flange interface can be used to connect the displacement a to the pipeline flange on the pipeline a. The power amplifier (i.e., the current regulating device e) is connected to the control system d through the aviation power interface. The initial current parameters or current regulating parameters are input to the power amplifier, which in turn drives the super magnetostrictive actuator 1 to work. The displacement amplification device 2 drives the piston 3 to generate sound waves in the pipeline.

[0117] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. An active control pipe noise silencing method, characterized by comprising: Includes a silencer (b) installed on a pipe (a) on one side of the water pump, and a hydrophone (c) installed on the pipe (a) between the silencer (b) and the water pump; The silencer (b) includes a magnetostrictive actuator (1) and a displacement amplification device (2) mounted on the magnetostrictive actuator (1). The vibrating head (10) of the magnetostrictive actuator (1) is connected to the displacement amplification device (2). A piston (3) is mounted at the end of the displacement amplification device (2). When the magnetostrictive actuator (1) is powered on, the vibrating head (10) reciprocates. The displacement amplification device (2) transmits the vibration of the vibrating head (10) to the piston (3) and makes the amplitude of the piston (3) greater than the amplitude of the vibrating head (10). The reciprocating motion of the piston (3) generates secondary sound waves in the pipeline (a). The secondary sound waves are used to eliminate the primary sound waves generated by the water pump. The noise reduction method includes the following steps: Noise information collection: When the water pump operates alone, the hydrophone (c) collects the primary sound pressure and primary sound frequency generated by the water pump. When the water pump and silencer (b) are working, the hydrophone (c) collects the real-time sound pressure and real-time frequency of the noise in the pipeline (a); Noise feedback: The hydrophone (c) feeds back the primary sound pressure and primary sound frequency from the noise information acquisition step to the control system (d), and the control system (d) feeds back the initial current parameters to the current regulating device (e). The hydrophone (c) feeds back the real-time sound pressure and real-time frequency of noise from the noise information acquisition step to the control system (d). The control system (d) compares the real-time sound pressure and real-time frequency of noise with the noise control parameters and feeds back the current adjustment parameters to the current adjustment device (e). Secondary acoustic modulation: The current regulating device (e) adjusts the current used to drive the super magnetostrictive actuator (1) according to the initial current parameters, and is used to set the secondary sound wave corresponding to the primary sound wave. The current regulating device (e) adjusts the current used to drive the super magnetostrictive actuator (1) according to the current regulating parameters, so that the real-time sound pressure and real-time frequency collected by the hydrophone (c) change to the noise control parameter level; The structure of the super magnetostrictive actuator (1) is as follows: The device includes a cup-shaped outer shell (19), in which a magnetostrictive rod (14) is installed in the center. The length direction of the magnetostrictive rod (14) is consistent with the depth direction of the outer shell (19), and a coil (16) is wrapped around the outside of the magnetostrictive rod (14). The coil (16) is surrounded by a ring-shaped permanent magnet (17). The outer ring of the permanent magnet (17) fits into the inner wall of the outer shell (19). The upper end face of the permanent magnet (17) is closed by an upper magnetic conductor (13) disposed inside the outer shell (19). The lower end face of the permanent magnet (17) is closed by a lower magnetic conductor (18) disposed at the bottom of the outer shell (19). The bottom of the outer casing (19) is a bottom cover (191) that is detachably connected to the side wall of the outer casing (19). A heat dissipation pipe (15) is provided between the super magnetostrictive rod (14) and the coil (16). The structure of the heat dissipation pipe (15) is as follows: it includes a columnar body (150) with an annular cross-section. The central hole of the columnar body (150) is fitted with the outer peripheral surface of the super magnetostrictive rod (14). The columnar body (150) is provided with multiple through holes (151). The multiple through holes (151) are arranged in a ring array with the central hole of the columnar body (150) as the center. The axis of the multiple through holes (151) is parallel to the axis of the columnar body (150). The lower ports of two adjacent through holes (151) are respectively the cooling water inlet (152) and the cooling water outlet (153). The columnar body (150) has multiple elongated grooves at both ends. After the two ends of the columnar body (150) are sealed with the upper magnetic conductor (13) and the lower magnetic conductor (18) respectively, the elongated grooves connect multiple through holes (151) to form a complete flow path. The cooling water inlet (152) and the cooling water outlet (153) are connected to the water inlet channel (193) and the water outlet channel (194) on the bottom cover (191) through two through holes located on the lower magnetic conductor (18). The water inlet channel (193) and the water outlet channel (194) are connected to the water supply system. Cooling water from the water supply system enters through the inlet channel (193), flows through the flow path formed by the through hole (151), and then flows out through the outlet channel (194).

2. The active control method for reducing pipeline noise as described in claim 1, characterized in that: The noise control parameter is the noise level in pipeline (a) when the silencer (b) and the water pump are working simultaneously, including the noise sound pressure value and the noise frequency value.

3. The active control method for reducing pipeline noise as described in claim 1, characterized in that: The initial current parameters include current magnitude and current frequency, and the current adjustment parameters include changes in current magnitude and current frequency.

4. The active control method for reducing pipeline noise as described in claim 1, characterized in that: The current regulating device (e) is a power amplifier.

5. A method for actively controlled pipeline noise reduction as described in any one of claims 1-4, characterized in that: The coil (16) is connected to an external power source through a wire, and the current through the coil and the wire is the current used to drive the super magnetostrictive actuator (1). The super magnetostrictive rod (14) is located between the upper magnetic conductor (13) and the lower magnetic conductor (18). A magnetic post (131) is installed at the upper end of the super magnetostrictive rod (14). The upper end of the magnetic post (131) passes through the upper magnetic conductor (13) and then an actuating rod (11) is installed. The axes of the actuating rod (11), the magnetic post (131) and the super magnetostrictive rod (14) coincide. The upper end of the actuating rod (11) is a vibrating head (10).

6. The active control method for reducing pipeline noise as described in claim 5, characterized in that: The top cover (192) is installed on the upper end of the outer shell (19), and a preload nut (121) is installed in the middle of the top cover (192). It also includes a floating seat (122) installed on the upper end of the magnetic column (131), the lower end of the actuating rod (11) is connected to the middle of the floating seat (122), the vibrating head (10) passes through the preload nut (121) and is located above the preload nut (121), the middle of the actuating rod (11) is sealed and slidably engaged with the preload nut (121), a disc spring (12) is fitted on the actuating rod (11) between the preload nut (121) and the floating seat (122), the preload nut (121) and the floating seat (122) are respectively engaged with the two ends of the disc spring (12), and the disc spring (12) is in a compressed deformation state.

7. The active control method for reducing pipeline noise as described in claim 6, characterized in that: It also includes an annular diaphragm (123) located between the top cover (192) and the upper magnetic conductor (13), the inner ring of the annular diaphragm (123) being fixedly connected to the floating seat (122), the outer ring of the floating seat (122) being fixedly connected to the inner wall of the outer shell (19), and the axis of the annular diaphragm (123) coinciding with the axis of the actuating rod (11).

8. A method for actively controlled pipeline noise reduction as described in any one of claims 1-4, characterized in that: The structure of the displacement amplification device (2) is as follows: Includes a cavity (21), which is a tubular structure. One end of the cavity (21) is sealed to an interface on the pipeline (a), so that the interior of the cavity (21) is connected to the pipeline (a). The other end of the cavity (21) is connected to the magnetostrictive actuator (1). The cavity (21) is equipped with an enlarged structure. The enlarged structure includes a first corrugated pipe (23) and a second corrugated pipe (25) arranged coaxially. The cross-sectional area of ​​the first corrugated pipe (23) is smaller than that of the second corrugated pipe (25). The lower end face of the first corrugated pipe (23) is connected to the upper end face of the second corrugated pipe (25) through a connecting plate (24). The upper end face of the first corrugated pipe (23) is blocked by a top plate (20), and the lower end face of the second corrugated pipe (25) is blocked by a bottom plate (26). The inner cavities of the first corrugated pipe (23) and the second corrugated pipe (25) are connected and filled with hydraulic oil. An oil injection hole (261) is provided on the bottom plate (26). A mounting seat (211) is provided on the inner wall of the cavity (21). The outer periphery of the connecting plate (24) is detachably installed on the mounting seat (211). The base plate (26) is connected to the vibrating head (10), and the piston (3) is installed on the top plate (20).

9. The active control method for reducing pipeline noise as described in claim 8, characterized in that: A third bellows (22) is provided outside the first bellows (23). The third bellows (22) is coaxially arranged with the first bellows (23). The upper end of the third bellows (22) is sealed to the lower part of the piston (3). The lower end of the third bellows (22) is sealed to the connecting plate (24). Air is filled between the first bellows (23) and the third bellows (22). An air inlet (31) for air filling is provided on the piston (3).

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