Dual-frequency ultrasonic transducer, dual-frequency driving circuit and ultrasonic cleaning machine

Abstract

The utility model provides a double-frequency ultrasonic transducer, a double-frequency driving circuit and an ultrasonic cleaning machine, and aims to realize switching of two different working frequencies by optimizing the structure of the transducer and the design of the driving circuit so as to meet diversified cleaning requirements. The transducer adopts a non-frequency multiplication design, the heat dissipation performance is improved by additionally arranging a circular heat dissipation aluminum sheet, the performance of the transducer is improved, the transducer generates a second peak value, and meanwhile, two piezoelectric ceramic sheets with the size of 45 * 5mm are arranged. The drive circuit adopts two independent designs which are respectively corresponding to low-frequency output and high-frequency output, and frequency conversion is realized through relay switching. In addition, the circuit also has the functions of overheating protection, overcurrent protection and state indication, so that the safety and reliability of equipment are improved. Through optimization design, the effects of efficient cleaning, low noise and fine cleaning are achieved, and the cleaning device is suitable for various cleaning scenes.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic cleaning technology, and in particular to a dual-frequency ultrasonic transducer, a dual-frequency drive circuit, and an ultrasonic cleaning machine. Background Technology

[0002] Ultrasonic cleaning technology, due to its high cleaning efficiency and wide applicability, has been widely used in various fields such as industry, medicine, electronics, and laboratories. The core component of an ultrasonic cleaner is the ultrasonic transducer, which converts electrical energy into mechanical energy (ultrasonic vibration), thereby generating a cavitation effect in the cleaning medium to clean the surface of objects. However, existing ultrasonic transducers and cleaning machines still have many problems and shortcomings in their design and application.

[0003] (a) Defects of single-frequency ultrasonic transducers and cleaning machines

[0004] Existing single-frequency ultrasonic transducers typically operate at only one fixed frequency, such as the common 40kHz or 28kHz. While this design is simple in structure, it has significant limitations in practical applications. Different cleaning objects and cleaning needs require different ultrasonic frequencies. For example, high-frequency ultrasound (such as 40kHz and above) is suitable for fine cleaning and can effectively remove tiny particles, but the cleaning speed is slower and it is not effective for thicker dirt; low-frequency ultrasound (such as 28kHz and below) has a faster cleaning speed, but it is difficult to meet the needs of high-precision cleaning. Therefore, a single-frequency transducer cannot simultaneously meet the needs of both rapid and fine cleaning.

[0005] Single-frequency ultrasonic transducers often require a compromise between cleaning speed and cleaning quality during the cleaning process. While high-frequency ultrasound offers better cleaning precision, it is slower and has limited ability to remove thick dirt; while low-frequency ultrasound, although fast, struggles to meet the requirements of high-precision cleaning. This trade-off limits the application of ultrasonic cleaners in complex cleaning scenarios.

[0006] Ultrasonic transducers generate heat during operation, especially at high power and for extended periods. Heat buildup can lead to performance degradation or even damage. Existing single-frequency transducers typically lack effective heat dissipation designs, resulting in shorter lifespans and limiting their application under high-power conditions.

[0007] Single-frequency ultrasonic transducers typically achieve optimal performance only at a specific frequency. However, in actual cleaning processes, different cleaning media and objects respond differently to ultrasonic frequencies. Therefore, single-frequency transducers are difficult to adapt to diverse cleaning needs, requiring frequent transducer replacements or adjustments to cleaning parameters, which increases operating costs and complexity.

[0008] Defects of existing dual-frequency ultrasonic transducers and cleaning machines

[0009] While some existing dual-frequency ultrasonic transducers offer two operating frequencies, these frequencies are often multiples of each other (e.g., 40kHz and 80kHz). Although this design theoretically simplifies circuit design, in practical applications, excessively high frequencies (e.g., 80kHz and above) lead to a significant decrease in cleaning effectiveness. While high-frequency ultrasound can provide better cleaning precision, its lower energy makes it difficult to effectively remove thick dirt, and the cleaning speed is also slower. Therefore, this dual-frequency design with multiples of each other has limited practical application value and is more suitable for laboratory research.

[0010] Existing dual-frequency drive circuits typically employ complex circuit structures to achieve frequency switching, such as using multiple sets of relays or complex combinations of electronic components to achieve dual-frequency output. This design not only increases circuit complexity and cost but also reduces system reliability and stability. Complex circuit structures are prone to failure, especially during high-power and long-term operation, where circuit stability and reliability are difficult to guarantee.

[0011] Existing dual-frequency ultrasonic transducers often struggle to guarantee consistent cleaning results at both frequencies when switching frequencies. Due to limitations in circuit design and transducer structure, differences in output power and cavitation effect between the two frequencies can lead to uneven cleaning performance. For example, high-frequency operation may result in higher cleaning precision but slower cleaning speed, while low-frequency operation offers faster cleaning speed but insufficient precision. This inconsistency limits the widespread adoption of dual-frequency ultrasonic cleaners in practical applications.

[0012] Existing dual-frequency ultrasonic transducers often fail to adequately consider heat dissipation and moisture protection in their structural design. Transducers generate significant heat during high-power operation, and current heat dissipation designs are typically inadequate, leading to excessively high transducer temperatures, impacting performance and lifespan. Furthermore, insufficient moisture protection makes internal components susceptible to damage from moisture, further limiting their application in humid environments.

[0013] In summary, existing single-frequency and dual-frequency ultrasonic transducers and cleaning machines have numerous problems and shortcomings in design and application, making it difficult to meet complex and ever-changing cleaning needs. Therefore, developing a dual-frequency ultrasonic transducer and cleaning machine that can simultaneously meet the needs of rapid and fine cleaning, has efficient heat dissipation performance, and a simple circuit design has significant practical importance and broad application prospects. Summary of the Invention

[0014] The present invention aims to provide an improved dual-frequency drive circuit and ultrasonic cleaner. Through the optimized design of the transducer structure and drive circuit, the switching between two working frequency points can be realized to meet different cleaning needs, while improving the heat dissipation performance and service life of the transducer.

[0015] The technical solution of this utility model is as follows: A novel dual-frequency ultrasonic transducer with non-frequency doubling is designed: a circular heat sink aluminum fin, made of AL2024 material and with a thickness of 2.5±0.085mm, is added to the structure of an existing conventional transducer. The position design of the heat sink aluminum fin ensures good heat dissipation, improves the stability and service life of the transducer; more importantly, it achieves two peak operating frequencies, that is, two high-efficiency load-matching operating frequencies. The stainless steel cleaning tank is first ground and sandblasted at the location where the heat sink aluminum fin is attached.

[0016] The transducer's piezoelectric ceramic sheet is designed with specific parameters, consisting of a 45×5mm sheet with a capacitance of 5000-5500pF. By optimizing the transducer's structure, it offers two operating frequencies: 32kHz and 48kHz. Both frequencies provide good cleaning performance; 32kHz offers faster cleaning speeds but slightly lower precision, while 48kHz provides a more refined cleaning effect with lower noise, making it suitable for fine cleaning.

[0017] To ensure proper operation of both frequencies, a dual-frequency drive circuit was designed, allowing for easy switching between different operating frequencies via output control. The mainboard circuit employs a dual-drive design: one drive for low frequency (32kHz) and the other for high frequency (48kHz). Frequency switching is achieved through a set of relays, enabling flexible adjustment of the output frequency according to actual cleaning requirements.

[0018] In the circuit design, specific component selection and parameter settings ensured the stability and reliability of the dual-frequency output. For example, the use of SPT4048 power transistors and FR155 rectifier diodes ensured efficient operation of the circuit at different frequencies.

[0019] The ultrasonic cleaning machine includes the aforementioned dual-frequency ultrasonic transducer and dual-frequency drive circuit, as well as a stainless steel cleaning tank (made of SUS304).

[0020] By optimizing the design of the transducer and circuitry, the cleaning machine achieves efficient cleaning at different frequencies while reducing noise and improving cleaning accuracy.

[0021] The ultrasonic cleaner of this invention has the following advantages: By adding heat dissipation aluminum fins, the heat dissipation performance of the transducer is effectively improved, extending its service life. The dual-frequency design meets different cleaning needs: 32kHz is suitable for rapid cleaning, while 48kHz is suitable for fine cleaning with lower noise. The circuit adopts a two-way drive design, with frequency switching achieved through relays, resulting in a simple structure, high reliability, and ease of implementation. Through optimized transducer and circuit design, this invention demonstrates significant improvements in cleaning performance and a superior user experience in practical applications. Attached Figure Description

[0022] Figure 1 This is a partial cross-sectional view of a dual-frequency ultrasonic transducer;

[0023] Figure 2 This is the circuit diagram of the driving section of the dual-frequency drive circuit. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Figure 1 This is a partial cross-sectional view of a dual-frequency ultrasonic transducer. A dual-frequency ultrasonic transducer is a high-efficiency, multi-functional ultrasonic vibration device designed to achieve stable output at two different operating frequencies (32kHz and 48kHz) through optimized structure and material selection, thus meeting diverse cleaning needs. The transducer's compact and rational structural design ensures its high efficiency and reliability in practical applications.

[0026] The stainless steel cleaning tank is one of the core components of an ultrasonic cleaner, used to hold the cleaning fluid and the items to be cleaned. It is made of SUS304 stainless steel, which has excellent corrosion resistance and mechanical strength, effectively resisting the erosion of the cleaning fluid while ensuring the structural stability of the tank. The cleaning tank is connected to the heat sink aluminum fins 3 of the transducer using a special epoxy adhesive, ensuring a tight bond between the transducer and the tank, thereby improving the sealing and stability of the entire cleaning system.

[0027] A specialized adhesive is used to connect the heat sink aluminum fins 3 to the stainless steel cleaning tank 1, ensuring a strong bond between them. This epoxy-based adhesive has high strength and good chemical resistance, maintaining its bonding performance in humid cleaning environments and preventing loosening or damage due to moisture penetration. This bonding method not only ensures a strong and reliable connection between the transducer and the cleaning tank but also effectively prevents liquid leakage, extending the equipment's service life.

[0028] The heat sink 3 is a crucial component of the transducer, its primary function being to provide heat dissipation while preventing moisture absorption. Made of AL2024 material, the heat sink possesses excellent thermal conductivity and mechanical properties. Its thickness is 2.5±0.085mm, and its diameter is 85mm. This size design ensures that the heat sink effectively covers the surface of the transducer's front cover 5, achieving excellent heat dissipation. The heat sink is directly fixed to the transducer's front cover 5 using a dedicated epoxy adhesive 2, with the other side used for connection to the stainless steel cleaning tank 1. This design not only improves the transducer's heat dissipation efficiency but also enhances its moisture resistance, enabling stable operation in various environments.

[0029] The transducer front cover 5 is part of the transducer body and is made of LY-12 aluminum alloy. This material is lightweight, high-strength, and has good corrosion resistance, effectively protecting the piezoelectric ceramic plates and other critical components inside the transducer. The transducer front cover is fixed to the transducer rear cover 10 with M12 hex socket screws 9, forming a sealed structure to prevent external environmental influences on the internal components. The heat dissipation aluminum fins 3 are directly bonded to the transducer front cover 5. This design not only improves heat dissipation efficiency but also enhances the structural stability of the entire transducer.

[0030] The first piezoelectric ceramic element 6 is one of the core components of the transducer. It measures 45×5mm and has a capacitance of 5000-5500pF. By optimizing the parameters and structural design of the piezoelectric ceramic element, the transducer can achieve stable output at two non-harmonic frequency points: 32kHz and 48kHz. The first piezoelectric ceramic element 6 is fixed to the transducer body by welding or fasteners and is connected to the negative electrode 12.

[0031] The second piezoelectric ceramic plate 7 is also one of the core components of the transducer. It measures 45×5mm and has a capacitance of 5000-5500pF. The second piezoelectric ceramic plate works in conjunction with the first piezoelectric ceramic plate to achieve dual-frequency output. The second piezoelectric ceramic plate is fixed inside the transducer body by welding or fasteners and is connected to the positive electrode 11.

[0032] The positive electrode 11 is an important component of the transducer, used to transmit electrical energy to the second piezoelectric ceramic plate 6. The positive electrode is made of copper, which has good conductivity and mechanical properties, enabling efficient energy transmission and ensuring the normal operation of the transducer. The positive electrode is fixed to the second piezoelectric ceramic plate 7 by welding or fasteners and is connected to the dual-frequency drive circuit via terminal wire 15.

[0033] The negative electrode 12 is also an important component of the transducer, used to transmit electrical energy to the first piezoelectric ceramic plate 6. The negative electrode is made of copper, which has good conductivity and mechanical properties, effectively transmitting electrical energy and ensuring the normal operation of the transducer. The negative electrode is fixed to the first piezoelectric ceramic plate 6 by welding or fasteners and is connected to the dual-frequency drive circuit via terminal wire 15.

[0034] Insulating sleeves 8 are installed on the outside of electrode plates 11 and 12. Their main function is to protect the electrode plates and prevent short circuits and external interference. The insulating sleeves are made of nylon, which has good insulation performance and mechanical strength. By installing insulating sleeves, the transducer electrode plates can operate in a safe and stable environment, thereby improving the reliability and service life of the entire device.

[0035] The transducer rear cover 10 is part of the transducer body and is made of galvanized 45# steel. This material has high strength and good corrosion resistance, effectively protecting the internal components of the transducer. The transducer rear cover is fixed to the transducer front cover 5 by M12 hex socket screws 9, forming a sealed structure to prevent the external environment from affecting the internal components. This design not only improves the structural stability of the transducer but also enhances its moisture resistance, enabling it to operate stably in various environments.

[0036] M12 hex socket screws 9 are used to secure the transducer front cover 5 and the transducer rear cover 10, ensuring the structural stability of the transducer body. By using high-strength screws, the transducer can maintain structural integrity during high-power operation, preventing loosening or damage due to vibration. The screws are tightened using terminal fastening nuts 14, ensuring a secure and reliable connection.

[0037] Terminal fastening screws 13 and terminal fastening nuts 14 are used to secure the connection between electrode plates 11 and 12 and the dual-frequency drive circuit. By using standard parts, a firm and reliable connection between the electrode plates and the drive circuit is ensured, preventing power transmission interruptions due to poor contact. This design not only improves the reliability of the transducer but also facilitates maintenance and replacement.

[0038] Terminal wire 15 is used to transmit electrical energy to the electrode plates 11 and 12 of the transducer. One end is connected to the electrode plate, and the other end is connected to the dual-frequency drive circuit to ensure efficient power transmission. By using high-quality terminal wires, the transducer can maintain stable power transmission during high-power operation, thereby improving the performance and reliability of the entire device.

[0039] Figure 2 This is the circuit diagram of the drive section of the dual-frequency drive circuit. This circuit is designed to drive a dual-frequency ultrasonic transducer, enabling switching between two operating frequencies: 32kHz (low frequency) and 48kHz (high frequency) to meet different cleaning needs. The two drive circuits are composed as follows:

[0040] 1. The low-frequency drive circuit (32kHz) mainly consists of the following components: Power transistor: Model SPT4048, used to amplify low-frequency signals and provide sufficient power output; L3 low-frequency winding and inductor L4 are used to match the impedance of the transducer, ensuring that the low-frequency signal can be efficiently transmitted to the transducer; Inductors: L21, L20, L25, and L26 are used for filtering and stabilizing current, ensuring the purity of the low-frequency signal; Capacitors: C1, C40, CX1, and C23 are used for filtering and signal conditioning, ensuring the stable operation of the power transistor; Resistors: R12 and R14 are used to limit current and condition the signal, protecting the power transistor from overcurrent damage. Relays: RELAY1 (K1) controls the on / off state of the drive circuit, relay RELAY2 (K7) selects the high-frequency or low-frequency range of transformer L3, and RELAY3 and GO-2C select whether to connect or short-circuit inductor L1.

[0041] The working principle of the low-frequency drive circuit (32kHz): Signal input: The low-frequency signal (32kHz) output from the control board is filtered and stabilized by inductors L21, L20, L25, and L26 to ensure the purity of the low-frequency signal; capacitors C1, C40, CX1, and C23 are used for filtering and signal conditioning to ensure the stable operation of the power transistor; Power amplification: The conditioned signal enters the power transistor SPT4048, which amplifies the input signal to provide sufficient power output; Inductors L21, L20, L25, and L26 and capacitors C1, C40, CX1, and C23 play a role in filtering and stabilizing the current during this process, ensuring the stability of the power output; Impedance matching: The amplified low-frequency signal is impedance matched by the L3 low-frequency winding and inductors L4 and L1 to ensure that the signal can be efficiently transmitted to the transducer; The design of the L3 low-frequency winding and inductors L4 and L1 allows the impedance of the low-frequency signal to match the input impedance of the transducer, thereby improving energy transmission efficiency. When the control board issues a low-frequency operating command, relay RELAY1 (K1) closes, activating the low-frequency drive circuit. Relay RELAY2 (K7) connects to the low-frequency setting of transformer L3, and RELAY3 and GO-2C connect to inductor L1, transmitting the signal to the transducer. When switching to high-frequency operation is required, the relays open, and the low-frequency drive circuit stops operating.

[0042] 2: The high-frequency drive circuit (48kHz) mainly consists of the following components: Power transistor: model SPT4048, used to amplify high-frequency signals and provide sufficient power output; Transformer: L3 high-frequency winding and inductor L4 are used to match the impedance of the transducer to ensure that the high-frequency signal can be efficiently transmitted to the transducer; Inductors: L21, L20, L25, L26, used for filtering and stabilizing current to ensure the purity of the high-frequency signal; Capacitors: C1, C40, CX1, C23, used for filtering and signal conditioning to ensure the stable operation of the power transistor; Resistors: R12, R14 are used to limit current and condition the signal to protect the power transistor from overcurrent damage; Relay RELAY1 (K1) controls the on / off state of the drive circuit, relay RELAY2 (K7) selects the high-frequency or low-frequency range of transformer L3, and RELAY3, GO-2C selects whether to connect or short-circuit inductor L1.

[0043] The working principle of the high-frequency drive circuit (48kHz): Signal input: The high-frequency signal (48kHz) output from the control board is conditioned by resistors R12 and R14 and capacitor C3 to ensure signal stability and purity. Power amplification: The conditioned signal enters the power transistor SPT4048, which amplifies the input signal to provide sufficient power output. Inductors L21, L20, L25, L26 and capacitors C1, C40, CX1, C23 play a filtering and current stabilizing role in this process, ensuring the stability of power output. Impedance matching: The amplified high-frequency signal is impedance matched through the high-frequency winding L3 and inductor L4 to ensure efficient signal transmission to the transducer. The design of L3 allows it to match the impedance of the high-frequency signal with the input impedance of the transducer, thereby improving energy transfer efficiency. When the control board issues a high-frequency operating command, relay RELAY1 (K1) closes, activating the drive circuit. Relay RELAY2 (K7) connects to the high-frequency setting of transformer L3. Relay RELAY3 (GO-2C) shorts inductor L1, activating the high-frequency drive circuit, and the high-frequency signal is transmitted to the transducer. When switching to low-frequency operation is required, relay RELAY1 (K1) opens, and the high-frequency drive circuit stops operating.

[0044] The circuit has the following advantages: (1) Independent high-frequency and low-frequency drive circuits: Two independent drive circuits are designed for amplification and transmission of low-frequency (32kHz) and high-frequency (48kHz) signals, respectively. This design ensures the purity and independence of the two frequency signals, avoids frequency interference, and improves the cleaning effect. (2) High-efficiency power amplification: The power transistor SPT4048 is used to amplify the input signal efficiently and provide sufficient power output. At the same time, the filtering effect of inductors and capacitors ensures the stability of the power output and extends the service life of the transducer. (3) Flexible frequency switching: The high-frequency and low-frequency switching is realized through relays, and users can flexibly select the working frequency according to the actual cleaning needs. This design not only improves the flexibility of the circuit, but also reduces the complexity and cost of the circuit. (4) Optimized impedance matching: Impedance matching is achieved through L3, T1 and T2 to ensure that the signal can be transmitted to the transducer efficiently. This design improves the energy transmission efficiency, reduces energy loss, and improves the cleaning effect. (5) Multiple protection functions: The circuit is designed with overheat protection (NTC) and overcurrent protection (FUSE) to ensure that the power supply can be cut off in time under abnormal conditions, protecting the transducer and circuit safety. In addition, the circuit is also designed with indicator lights (LED) and buzzers (BUZ) to display the current working status and fault alarms.

[0045] The above-disclosed embodiments are merely one example of the present utility model and should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of the present utility model still fall within the scope of the present utility model.

Claims

1. A dual frequency ultrasonic transducer, characterized by, It comprises: The transducer body is provided with a transducer back cover, a first piezoelectric ceramic sheet, a negative electrode sheet connected thereto, a second piezoelectric ceramic sheet, a positive electrode sheet connected thereto, and a transducer front cover. A circular heat dissipation aluminum sheet with a diameter larger than that of the transducer front cover is directly glued to the transducer front cover. The other side of the circular heat dissipation aluminum sheet is used for gluing a stainless steel cleaning cylinder. The transducer has two working frequency points with no frequency multiplication relationship.

2. The dual frequency ultrasonic transducer of claim 1, wherein The first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are 45*5mm. The diameter of the circular heat dissipation aluminum sheet is 85mm, the thickness is 2.5±0.085mm, the material is AL2024, and the thickness is 2.5±0.085mm.

3. The dual frequency ultrasonic transducer of claim 2, wherein The capacitance value of the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet is 5000-5500pF.

4. The dual frequency ultrasonic transducer of claim 1, wherein, The heat dissipation aluminum sheet of the transducer is fixed on the stainless steel cleaning tank by special epoxy adhesive.

5. The dual frequency ultrasonic transducer of claim 4, wherein, The stainless steel cleaning tank is first polished and sandblasted at the position where the heat dissipation aluminum sheet is pasted.

6. A dual frequency drive circuit, characterized by The driving circuit has two ultrasonic wave driving outputs, a low-frequency driving circuit, and a high-frequency driving circuit. Both driving outputs are connected to the negative electrode sheet and the positive electrode sheet of the double-frequency ultrasonic transducer of any one of claims 1 to 4 through a group of relays, and the working frequency is switched by controlling the relays.

7. The dual frequency drive circuit of claim 6, wherein, The low-frequency driving circuit and the high-frequency driving circuit each include the following key elements: a power tube with model SPT4048 for amplifying the input signal and providing sufficient power output; transformers T1 and T2 for matching the impedance of the transducer; inductors L1 and L2 for filtering and stabilizing current to ensure signal purity; capacitors C1, C2 and C3, C4 for filtering and signal conditioning to ensure stable operation of the power tube; resistors R1, R2 and R3, R4 for limiting current and signal conditioning to protect the power tube from overcurrent damage.

8. The dual frequency drive circuit of claim 7, wherein, The low-frequency driving circuit and the high-frequency driving circuit each use independent transformers T1 and T2 for impedance matching to ensure the purity and independence of the two frequency signals, avoid frequency interference, and improve cleaning effect.

9. The dual frequency drive circuit of claim 8, wherein, The circuit also includes the following protection functions: an overheat protection device for monitoring the operating temperature of the circuit and automatically cutting off the power supply when the temperature exceeds the preset value to protect the safety of the transducer and the circuit; an overcurrent protection device for monitoring the current of the circuit and automatically cutting off the power supply when the current exceeds the preset value to prevent circuit overload damage; indicator lights and a buzzer for displaying the current working state and fault alarm to facilitate users to promptly understand the equipment operation.

10. An ultrasonic cleaning machine characterized by comprising: It comprises: The double-frequency ultrasonic transducer of any one of claims 1 to 5; the double-frequency driving circuit of any one of claims 6 to 9; A stainless steel cleaning tank, and a circular heat dissipation aluminum sheet of the double-frequency ultrasonic transducer is glued to the stainless steel cleaning tank by epoxy.

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