Sonotrode

Abstract

a sonotrode (10) comprising a cooling fluid system (12), wherein the cooling fluid system (12) comprises an evaporator (14), wherein the sonotrode (10) comprises the evaporator (14) which is arranged in the sonotrode (10) in such a way as to evaporate a cooling fluid, in particular starting from the form of a wet vapor, in order to cool the sonotrode (10), wherein a throttle (15) and / or an expansion valve (16) is arranged upstream of the evaporator (14) in such a way as to carry out a pre-expansion of the liquid or liquefied cooling fluid before the cooling fluid is transferred into the evaporator (14).

Description

[0001] The application concerns a sonotrode.

[0002] Sonotrodes require partial cooling during ultrasonic welding. Air cooling is typically used for this purpose. However, the heat capacity of air is relatively low. Therefore, a large volume of air is needed to dissipate the heat. The obvious solution of using water as a cooling medium is not feasible (at least while the sonotrode is subjected to sound during welding) because the water causes undesirable side effects such as cavitation.

[0003] Currently, sonotrodes are cooled only indirectly with air or by heat sinks, which are either integrated into the sonotrode or pressed against it during idle phases. Compressed air cooling is expensive, its cooling capacity is limited, and air cooling is often noisy. Heat sinks on the sonotrode often lead to component collisions, and their heat capacity is quickly exhausted. Cooling with external heat sinks increases cycle time, and heat transfer is also limited. Water cooling is difficult to implement due to the noise, and cavitation or other undesirable side effects can occur during the process.

[0004] The purpose of the invention is to improve cooling.

[0005] The problem is solved by a sonotrode with the features of claim 1.

[0006] According to one aspect, the task is solved in particular by a sonotrode that includes a cooling fluid system. The cooling fluid system includes, in particular, an evaporator. The sonotrode includes, in particular, the evaporator, which is arranged within the sonotrode in such a way as to evaporate a cooling fluid, especially starting from the form of wet vapor, in order to cool the sonotrode. A throttle—alternatively or additionally an expansion valve—can be arranged upstream of the evaporator in such a way as to carry out a pre-expansion of the liquid or liquefied cooling fluid before the cooling fluid is transferred to the evaporator.

[0007] A sonotrode is part of a vibrating device. It is commonly used in various applications, including, for example, ultrasonic welding.

[0008] Ultrasonic welding is a well-established process for joining thermoplastic materials using form-fit or material-fit methods. Its applications range from the automotive and electrical industries to the packaging, medical, and hygiene industries.

[0009] Typical ultrasonic welding devices consist of an ultrasonic generator, a converter, optionally an amplitude transformer, and a welding tool, the sonotrode. The ultrasonic generator produces a high voltage at the desired ultrasonic frequency from an applied mains voltage. The electrical oscillation of the ultrasonic generator is then converted into a mechanical longitudinal oscillation in the converter using the inverse piezoelectric effect and transmitted to the amplitude transformer or the welding tool. The amplitude of the mechanical oscillation can be increased or decreased using the amplitude transformer, which may be positioned between the converter and the welding tool. Additionally, the amplitude transformer can also serve as a support for the oscillating assembly consisting of the converter, amplitude transformer, and welding tool.The sonotrode, as the actual active welding tool, transmits the mechanical vibration to the components being joined. The sonotrode has a sealing surface through which it makes contact with the material being processed.

[0010] Mechanical vibrations at ultrasonic frequencies generate frictional heat in the plastic being joined, causing the molecules within the plastic to move. As a result, the plastic softens and begins to melt, allowing the components to bond together when a specific pressure is applied for a certain period of time. The components are then firmly bonded at the molecular level. This process utilizes sound energy, typically in the frequency range of 15 kHz to 10 GHz, to create a strong and permanent bond between two components.

[0011] In ultrasonic welding, a sonotrode is used to join two plastic or metal parts by applying high-frequency vibrations with a precise frequency (usually 20–40 kHz) and amplitude. This process generates heat and friction, causing the materials to melt and fuse together. A sonotrode is a tool used in ultrasonic welding, a process that employs high-frequency vibrations (typically in the specific range of 15–35 kHz) to join two materials. The sonotrode is one of the most important components in an ultrasonic welding machine.

[0012] In general, a sonotrode is designed as a metal rod or probe that serves to transfer the ultrasonic energy from the transducer of the welding machine (which converts electrical energy into mechanical vibrations) to the workpiece being welded. It is usually made of a high-strength, wear-resistant material and has a precisely controlled shape and size.

[0013] During welding, the sonotrode vibrates at a frequency in the ultrasonic range, which, in a locally limited area, can stimulate molecular movements as described elsewhere herein, in order to melt the material and / or materials, thereby enabling joining by applying pressure to the components to be joined, resulting in a strong connection.

[0014] In surface treatment, sonotrodes can be used for surface cleaning, deburring and texturing of materials such as plastics, metals and ceramics.

[0015] Sonotrodes are widely used in industries such as aerospace, automotive, consumer goods, and medical technology, where precision and efficiency are crucial. They are employed where precise joining of materials is essential. Sonotrodes can be used to weld a wide range of materials, including metals, plastics, composites, and ceramics. Examples of metals that can be processed include aluminum, copper, and steel. Examples of plastics that can be processed include polyethylene, polypropylene, and polycarbonate. Examples of composite materials that can be processed include carbon fiber-reinforced polymers.

[0016] The sonotrode described here and elsewhere is designed with enhanced cooling properties, specifically a cooling system for cooling the sonotrode during welding or other applications. This enables more efficient and reliable operation of the ultrasonic welding machine or other devices that incorporate a sonotrode.

[0017] The sonotrode is made primarily from high-strength, wear-resistant materials such as titanium alloys, which can withstand the strong vibrational forces during ultrasonic welding. The shape and size of the sonotrode are carefully controlled to optimize its performance and ensure precise transmission of sound energy.

[0018] In conjunction with the sonotrode, a cooling fluid system can be designed to supply a cooling fluid – also referred to as a refrigerant – to cool the sonotrode during welding, particularly in a closed cooling fluid circuit as described elsewhere herein.

[0019] Key components of the cooling fluid system can be the following components, which can be freely combined with each other, i.e., in any form, as long as the described cooling of the sonotrode or its components can be implemented:

[0020] The cooling fluid system uses, in particular, a cooling fluid which, especially in a gaseous state, particularly as wet vapor, enters the sonotrode and then evaporates to provide cooling. The cooling fluid supply and discharge are arranged on the sonotrode, particularly in conjunction with an evaporator, to bring the components of the sonotrode to be cooled into contact with the cooling fluid, especially in its wet vapor form. In particular, the area of ​​the ultrasonic generator can be supplied with wet vapor, and the ultrasonic generator can be arranged within an evaporator.

[0021] A compressor compresses the gaseous refrigerant, which can be fed to the compressor via a return flow from the sonotrode's evaporator. This allows for pre-compression to facilitate the liquefaction of the refrigerant in a condenser. The condenser can be coupled to a heat exchanger to further liquefy the refrigerant and dissipate heat to the surroundings.

[0022] A heat exchanger can be used in conjunction with a condenser to liquefy the pre-compressed coolant so that it can be expanded again through an expansion valve. The expansion valve reduces the pressure of the coolant, causing it to expand and return to a gaseous state. This allows it to exist as wet vapor, enabling it to provide cooling through the evaporation of the remaining fluid droplets.

[0023] The system can be configured for the following system operation: During welding, the sonotrode vibrates at high frequencies and generates heat that needs to be dissipated.

[0024] The cooling fluid enters the sonotrode in a gaseous state (wet vapor) and evaporates, thereby cooling the environment inside the sonotrode, especially the ultrasonic transducer.

[0025] When the refrigerant evaporates, it absorbs heat from the sonotrode and its components, storing this heat in the gaseous phase of the cooling fluid. This stored heat can then be extracted from the cooling fluid circuit via the heat exchanger in the condenser by being released to the environment.

[0026] Afterwards, the condensed cooling fluid can be expanded again through the expansion valve (the same applies to the throttle), causing it to return to a gaseous state, after which the cooling cycle is repeated. By transitioning to the wet vapor phase (also called wet vapor form or wet vapor state), the cooling fluid is once again ready to absorb heat from the sonotrode.

[0027] Pre-expansion of the refrigerant through the expansion valve can therefore occur shortly before it enters the sonotrode, in order to transfer wet vapor into the evaporator. In this specific context, "shortly before the sonotrode" means that the expansion process (evaporation) takes place near the point where the refrigerant enters the sonotrode, specifically to provide wet vapor at the point of cooling.

[0028] The expansion valve is a component in this cooling fluid system responsible for regulating the flow rate and pressure of the liquid cooling fluid (the refrigerant) as it enters the sonotrode. Its design ensures optimal expansion. The expansion valve expands the liquid cooling fluid to its maximum capacity, enabling efficient heat transfer between the cooling fluid and the sonotrode. This results in uniform cooling. The expanded cooling fluid is then distributed evenly throughout the sonotrode, ensuring consistent cooling performance.

[0029] The expansion process upstream of the evaporator offers several advantages in this system. It enables increased cooling efficiency. The expansion of the liquid refrigerant increases its ability to absorb heat energy, resulting in more effective cooling.

[0030] It enables improved heat transfer. The evaporation of the liquid cooling fluid improves the heat transfer coefficient between the cooling fluid (as a refrigerant in wet vapor form) and the sonotrode, thus enabling faster and more efficient cooling.

[0031] In summary, the expansion process in this system includes the following: The expansion of the liquid refrigerant is enabled. The liquid refrigerant is expanded by an expansion valve. As a result of the expansion, the liquid refrigerant evaporates into a gas, specifically wet vapor. A further cooling effect can be achieved in the evaporator through the evaporation of this wet vapor. The evaporation of the refrigerant has a cooling effect on the sonotrode.

[0032] The expanded cooling fluid is distributed throughout the sonotrode, thereby improving heat transfer and enabling efficient cooling. This expansion process plays a particularly important role in maintaining the desired temperature within the sonotrode during the welding process.

[0033] In particular, it is provided that a continuous flow of cooling fluid can be directed through the evaporator in the sonotrode. This allows for continuous cooling.

[0034] This allows for high cooling capacity compared to air-based cooling systems. The fluid cooling system operates almost silently, eliminating the noise pollution that can be associated with traditional cooling methods. The fluid cooling system reduces operating costs by minimizing energy consumption and increasing cycle times.

[0035] The cooling fluid system described herein and elsewhere, particularly with a closed cooling fluid circuit, offers an efficient and reliable solution for cooling sonotrodes during the welding process, with improvements in performance, energy efficiency, and reduced operating costs. It can provide high cooling capacity. The term "high cooling capacity" refers specifically to the cooling fluid system's ability to dissipate heat from the sonotrode at a rate significantly higher than that achievable with conventional air cooling methods (available and known on the filing or priority date).

[0036] In one respect, the cooling fluid system particularly features a cooling fluid circuit. This can be designed and arranged in such a way as to repeatedly circulate the cooling fluid over the sonotrode to cool the sonotrode.

[0037] A cooling fluid system can have a closed-loop cooling fluid circuit. A closed-loop system is a type of cooling circuit in which the cooling fluid, acting as the refrigerant, can circulate continuously between the evaporator, condenser, and expansion valve without significant leaks or losses.

[0038] The refrigerant fluid flows through a closed circuit, which may include the following: an evaporator, where the refrigerant fluid absorbs heat from the surroundings – the area or component to be cooled; a condenser, where the refrigerant fluid releases heat to the surroundings (external to the sonotrode, and in particular, at a distance); and an expansion valve, where the high-pressure liquid refrigerant can expand and enter the evaporator as low-pressure vapor (in the form of wet vapor). The circuit is considered closed, in particular, if there are no significant leaks or refrigerant losses within the system. Furthermore, "closed" can also refer to the fact that the refrigerant fluid is continuously reused in the circuit to be available for cooling in a further cycle.

[0039] A continuous flow can be established. In particular, the cooling fluid flows continuously through the circuit, with minimal interruption or shutdown.

[0040] This enables efficient cooling. Cooling fluid systems with closed circuits can achieve high efficiency and effective cooling performance due to the continuous flow of cooling fluid.

[0041] A closed circuit can include an evaporator, a condenser, and an expansion valve. In some embodiments, as described elsewhere herein, a compressor may also be included. The evaporator is, in particular, where the refrigerant absorbs heat from the surroundings, causing it to evaporate. This can be located inside a sonotrode, where, in particular, the ultrasonic transducer can be cooled. The condenser, also called the condenser, is, in particular, where the high-pressure, gaseous refrigerant releases its heat to the surroundings and condenses into a liquid. The expansion valve, in particular, regulates the flow of the refrigerant from the condenser to the evaporator, causing the high-pressure liquid refrigerant to expand into low-pressure vapor—in particular, wet vapor. This can be located near the area to be cooled.

[0042] In summary, a closed-loop cooling system is a type of refrigeration circuit in which the refrigerant circulates continuously between the evaporator, condenser, and expansion valve. This design ensures efficient cooling performance, lower energy consumption, and increased safety by minimizing leaks and losses.

[0043] In one respect, the cooling fluid system includes a condenser, which is arranged within the cooling fluid system, particularly within the cooling fluid circuit, in such a way as to liquefy the cooling fluid. This allows the cooling fluid to be converted from its gaseous phase to its liquid phase, in order to evaporate it again in an evaporator within the cooling fluid system, thus extracting energy from the area of ​​the sonotrode that needs to be cooled.

[0044] From one perspective, the cooling fluid circuit features a condenser downstream of the sonotrode being cooled, in order to re-condense the cooling fluid carried away from the sonotrode and then return the condensed, liquefied cooling fluid to the sonotrode for evaporation. This allows for the implementation of a closed cooling fluid circuit, as described elsewhere herein.

[0045] From one perspective, a compressor is installed upstream of a condenser to pre-compress the refrigerant. Some examples of closed-loop refrigerant systems use a compressor to compress the refrigerant before it enters the condenser.

[0046] From one perspective, the sonotrode is specifically a rivet sonotrode.

[0047] A rivet sonotrode is a type of sonotrode whose primary function is to create a strong connection between two components by using high-frequency vibrations to form a rivet-like joint. A rivet is a component that can be inserted through a recess in a workpiece to join two components. The rivet sonotrode is specifically designed to interact with a portion of the rivet in such a way that it deforms, preventing the rivet from being pulled back through the recess. This type of sonotrode is typically used in applications requiring a strong, localized connection, such as...Sonotrodes are used for joining sheet metal parts, creating reinforced joints for structural components, and / or welding small, thin materials. Alternatively or additionally, rivet sonotrodes can be designed for riveting plastic parts. Furthermore, there are sonotrodes used, for example, for joining metal parts. In both cases, the sonotrodes become very hot during use (without adequate cooling).

[0048] Riveting sonotrodes often have a special tip or nose that allows the user to precisely control the riveting process. This can include adjusting the distance between the tip and the workpiece, as well as controlling the amplitude and frequency of the vibrations.

[0049] A metal sonotrode is specifically a type of sonotrode used for joining metals. Such sonotrodes are typically made of hardenable steel. Sonotrodes for other applications can be manufactured from special steels, titanium, or aluminum alloys. Regarding the cooling of a sonotrode described here, there are no limitations on the material the sonotrode is made of.

[0050] According to one aspect, reversibly detachable shut-off valves can be arranged upstream and downstream of the sonotrode in the cooling fluid circuit to reversibly decouple the sonotrode from the cooling fluid circuit, the shut-off valves being designed to lock during decoupling in order to retain any residual cooling fluid between the two shut-off valves.

[0051] This addresses challenges in handling the cooling fluid, particularly during maintenance and / or replacement of the sonotrode, as in some designs the cooling fluid used in the cooling system may be environmentally hazardous or flammable, thus requiring careful handling and disposal. The sonotrode, in conjunction with the reversibly detachable shut-off valves, makes it possible to prevent the cooling fluid from escaping into the atmosphere. Instead, the sonotrode can be removed from the cooling system, specifically the cooling circuit, in a controlled manner for maintenance and / or replacement, allowing for the controlled disposal of the cooling fluid.

[0052] This allows for regular maintenance that may be required to ensure the proper functioning of the system, including cleaning and replacing components as needed.

[0053] From one perspective, the connection of the cooling fluid system (on the sonotrode) can be located at the junction. The connection (similar to a vacuum connection on the sonotrode) is situated at a branch point. The gaseous cooling fluid then circulates, particularly through the sonotrode, and in some embodiments is drawn off by the compressor, compressed, and liquefied again in the heat exchanger (in conjunction with the condenser). At the expansion valve, the cooling fluid is liquid again, expands, and thus returns to a gaseous state.

[0054] The cooling fluid system features a connection point at the joint (where the sonotrode meets other components) through which cooling fluid can flow into the sonotrode. This connection is similar to a vacuum port, meaning it provides a sealed and controlled environment for the cooling fluid entry. Furthermore, this connection point is the point that moves the least when the ultrasonic transducer is active, thus reducing additional stress on the connections.

[0055] As soon as the gaseous refrigerant enters the sonotrode, it flows primarily through the interior of the sonotrode, where it absorbs heat from the vibrating (metal) surface. The refrigerant then exits the sonotrode and is drawn into the compressor, which compresses it and forces it back through the heat exchanger, where it is liquefied again in a condenser.

[0056] One aspect is the inclusion of an external heat exchanger to transfer heat from condensation to the surrounding environment. When the refrigerant evaporates, it absorbs heat from the sonotrode and its components, storing it in the gaseous phase of the refrigerant fluid. This stored heat can then be extracted from the refrigerant circuit via the heat exchanger in the condenser by being released to the environment.

[0057] In other words, and to summarize, a refrigeration system – specifically the cooling fluid system – with a corresponding refrigerant – the cooling fluid – is used for cooling.

[0058] The cooling capacity of a refrigeration system is extremely high compared to air, which is why the sonotrode (with low power) could be cooled below freezing. The cooling process is also virtually silent, and there are no adverse effects from liquids. Thanks to the high cooling capacity and low operating costs, cycle times can be increased.

[0059] The use of liquid refrigerant, which expands (evaporates) just before the sonotrode, can cool the refrigerant (significantly), allowing it to absorb a large amount of energy. The sonotrode is a key component of the cooling circuit in which the refrigerant circulates. The heat is then dissipated to the environment, primarily via an external heat exchanger.

[0060] Alternative implementations and designs for the described refrigeration and cooling fluid system could include the use of an air-cooled sonotrode. Instead of using a refrigerant as the cooling fluid, the sonotrode could be air-cooled using a heat sink or a finned surface. While this design would eliminate the need for the cooling fluid system described herein, it would significantly reduce the cooling capacity.

[0061] A water-cooled sonotrode would theoretically be conceivable, whereby the sonotrode could be cooled by the circulation of water through a jacket or channel surrounding the metal surface. This design would offer high cooling capacity, but could require additional pumps and piping, and negative effects such as cavitation could also occur.

[0062] Solid-state cooling could be implemented. This would allow the use of advanced solid-state materials such as thermoelectric coolers (TECs) for direct cooling of the sonotrode, eliminating the need for a coolant or cooling fluid. However, these designs are complex to construct, difficult to handle, and expensive to operate.

[0063] A gas-cooled sonotrode could be used. Instead of a refrigerant, the sonotrode could be cooled by circulating a gas, such as nitrogen or argon, through its interior. However, these gases are very expensive, are consumed in a short time (unlike the design described here) when using a refrigerant as a cooling fluid, which can be used cyclically, and the cooling capacity of the gas-cooled sonotrode does not match that of the design proposed here.

[0064] These alternative designs and implementations offer different compromises in terms of cooling performance, complexity, cost, and reliability. The choice of cooling system depends on specific requirements and constraints, such as temperature range, cooling capacity, power consumption, and maintenance needs. The use of a cooling fluid system with a sonotrode, as described here, is characterized by high cost-efficiency, manageable complexity in both handling and construction, and high cooling performance.

[0065] Suitable refrigerants for the cooling fluid system described herein should possess properties that enable efficient cooling of the sonotrode during the welding process while also being safe and environmentally friendly. Here are some possible refrigerant options, although not all conceivable refrigerants can be used in every case, for example, due to legal and / or contractual agreements, such as regarding prohibited chlorofluorocarbons, which may be replaced by appropriate, harmless substances: The refrigerant R-134a (1,1,1,2-tetrafluoroethane), widely used in air conditioning systems, has a relatively low boiling point (-26°C) and is non-toxic and non-flammable.

[0066] R-410A (pentane difluoromethane mixture) is a high-performance refrigerant with a low boiling point (-51°C) that is used in many commercial air conditioning systems and has good heat transfer properties.

[0067] With a boiling point of -22°C, R-32 (difluoromethane) is a popular choice for high-efficiency air conditioners due to its low GWP (Global Warming Potential) and non-toxicity.

[0068] HCFC-123 (1,1-Dichloro-2,3-difluoroethane) is a refrigerant with a boiling point of -29°C, which is used in various industrial applications due to its high heat transfer coefficients and relatively low GWP.

[0069] HFO-1336mzz (1,1-Difluoro-2,3-dimethylpropane) is a new generation of HFO (hydrofluoroolefin) refrigerants with a boiling point of -15°C and is non-toxic and non-flammable.

[0070] NH3 (ammonia) is an environmentally friendly and relatively inexpensive refrigerant with a boiling point of -33°C and has been used in industrial applications for decades.

[0071] The following factors can be taken into account when selecting a refrigerant: Safety for health and the environment can be of particular importance. It is essential to ensure, in particular, that the refrigerant is non-toxic and non-flammable and does not release any hazardous fumes during operation or in the event of a leak.

[0072] Environmental impacts can be taken into account. In particular, a refrigerant should be selected with a low GWP (Global Warming Potential) and minimal ozone depletion potential (ODP).

[0073] The heat transfer properties can be of particular importance. In particular, a refrigerant should be selected to have a high heat transfer coefficient in order to cool the sonotrode efficiently.

[0074] Compressor compatibility is particularly important to consider. It must be ensured that the selected refrigerant (the cooling fluid) is compatible with the compressor used in the cooling system.

[0075] Costs and availability can be taken into account to enable price efficiency and reduce potential risks in the supply chain.

[0076] The most suitable refrigerant ultimately depends on the specific application requirements, local regulations, and the manufacturer's recommendations.

[0077] In the following, an embodiment, further development, and example of the invention will be explained in more detail with reference to the accompanying drawing. Fig. Figure 1 shows a schematic representation of an exemplary embodiment of a sonotrode.

[0078] Fig.Figure 1 shows a sonotrode 10 as a rivet sonotrode 11; metal sonotrodes are also conceivable. The sonotrode 10 is connected to fluid hoses 32 via a connection 26 of a cooling fluid system 12. The cooling fluid system 12 is designed as a closed cooling fluid circuit 18 to repeatedly circulate the cooling fluid—also referred to as the refrigerant, a liquefiable medium capable of absorbing heat energy during evaporation—through cycles of compression, liquefaction, expansion, and evaporation via an evaporator 14, which can be located within the sonotrode 10, to cool components located therein, such as the ultrasonic transducer (not shown). The sonotrode 10 has through-holes 38 with sealing plugs 42, particularly at its active tip 40. A receptacle for a rivet is schematically indicated.

[0079] The connection 26 (similar to the vacuum connection) is located at junction 28 to minimize vibrations from the ultrasonic transducer (not shown). The gaseous refrigerant 100 (the cooling fluid) then circulates through the sonotrode 10 and an evaporator 14 located therein. It is then drawn off by the compressor 22, compressed, and liquefied again in the condenser 20 to form a liquid refrigerant 200. The refrigerant is then available in liquid form at the expansion valve 16 – or alternatively or additionally at the throttle 15 – where it can expand and thus become gaseous again, in order to be fed back to the evaporator 14.

[0080] The condenser 20 is coupled to an external heat exchanger 30 in such a way as to transfer heat to an environment spaced apart from the sonotrode 10. The condenser 20 and the compressor 22 upstream of it can be arranged in a housing 34 and connected to each other via a fluid guide 36, for example as a bore in the housing 34.

[0081] Refrigerants used as cooling fluids are partly environmentally harmful and partly flammable and should not simply be released into the atmosphere. This is particularly problematic during sonotrode replacement and / or maintenance. Appropriate couplings and shut-off valves 24 can be provided to minimize refrigerant leakage. These allow for the reversible removal of the sonotrode 10, locking during removal to prevent the cooling fluid from escaping the fluid hoses 32. This enables the sonotrode 10 to be replaced and / or serviced without the release of cooling fluid that could be harmful to health or the environment. REFERENCE MARK LIST 10 sonotrodes 11 rivet sonotrode 12 Cooling fluid system 14 evaporators 15 throttle 16 Expansion valve 18 Cooling fluid circuit 20 Capacitor 22 Compressor 24 shut-off valve 26 connection 28 Junction 30 heat exchangers 32 fluid hoses 34 building structures 36 Fluid guidance 38 Through hole with sealing plug 40 active top 42 sealing plugs 100 gaseous refrigerant 200 liquid refrigerant

Claims

[1] Sonotrode (10) comprising a cooling fluid system (12), wherein the cooling fluid system (12) has an evaporator (14), wherein the sonotrode (10) has the evaporator (14) which is arranged in the sonotrode (10) in such a way as to evaporate a cooling fluid, in particular starting from the form of a wet vapor, in order to cool the sonotrode (10), wherein a throttle (15) and / or an expansion valve (16) is arranged upstream of the evaporator (14) in such a way as to carry out a pre-expansion of the liquid or liquefied cooling fluid before the cooling fluid is transferred into the evaporator (14). [2] Sonotrode (10) according to claim 1, wherein the cooling fluid system (12) comprises a cooling fluid circuit (18) such as to repeatedly pass the cooling fluid over the sonotrode (10) for cooling the sonotrode (10). [3] Sonotrode (10) according to one of claims 1 or 2, wherein the cooling fluid system (12) comprises a condenser (20) arranged in the cooling fluid system (12), in particular in the cooling fluid circuit (18), in order to liquefy a cooling fluid. [4] Sonotrode (10) according to claim 3, wherein the cooling circuit (12) comprises the condenser (20) downstream of the sonotrode (10) to be cooled in order to re-condense cooling fluid carried away from the sonotrode (10) to be cooled in order to guide the condensed, liquefied cooling fluid again for evaporation in the direction of the sonotrode (10). [5] Sonotrode (10) according to one of the preceding claims, wherein a compressor (22) is connected upstream of a condenser (20) to pre-compress the cooling fluid. [6] Sonotrode (10) according to one of the preceding claims, wherein the sonotrode (10) is a rivet sonotrode (11). [7] Sonotrode (10) according to one of the preceding claims, wherein reversibly decoupleable shut-off valves (24) are arranged in the cooling fluid circuit (18) upstream and downstream of the sonotrode (10) in order to reversibly decouple the sonotrode (10) from the cooling fluid circuit (18), wherein the shut-off valves (24) are designed to close upon decouplement in order to retain residual cooling fluid between the two shut-off valves (24). [8] Sonotrode (10) according to one of the preceding claims, wherein the connection (26) of the cooling fluid system (12) is arranged at the node point (28). [9] Sonotrode (10) according to one of the preceding claims, wherein an external heat exchanger (30) is provided such that heat from the condensation is transferred to an environment.

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