Method for coupling an ultrasonic converter to a component

Abstract

The invention relates to a method (1) for coupling an ultrasonic converter to a component (2), comprising the steps of: providing (3) an adapter (4) having a contact surface (5) for the component (2), a through-hole (6) proceeding from its contact surface (5), and an anchoring (7) for the ultrasonic converter; applying (10) the contact surface (5) of the provided adapter (4) to the surface (11) of the component (2); welding (12) the applied adapter (4) to the component (2) by means of a circumferential weld seam (13) while leaving at least one gap (14) in the weld seam (13); introducing (15) casting compound between the contact surface (5) of the adapter (4) and the surface (11) of the component (2) through the through-hole (6) until casting compound exits from the at least one gap (14); allowing (16) the introduced casting compound to cure; and anchoring (17) the ultrasonic converter on the anchoring (7) of the adapter (4).

Description

[0001] Method for coupling an ultrasonic converter to a

[0002] component

[0003] The present invention relates to a method for coupling an ultrasonic converter to a component.

[0004] In order to prevent adhering contamination or blockages caused by contamination on or in components such as silos, heat exchangers, pipelines, troughs, hoppers, etc. - and to loosen adhering contamination ("anti-fouling"), it is known, for example in power plants or industry, in particular the chemical, petrochemical, construction or paper industries, to set the respective component, in particular its wall, into high-frequency vibrations using a coupled ultrasonic converter. The ultrasonic converter usually has a piezoceramic ultrasonic actuator that can be coupled to the component via a metallic vibrating body. Repeated ultrasonic excitation in the frequency range between approximately 18 kHz and 50 kHz, e.g. at intervals of several seconds for a few seconds, loosens adhering contamination and prevents (or at least reduces) new deposits.

[0005] It goes without saying that the requirements for coupling the ultrasonic converter to the component are demanding: The coupling must mechanically withstand repeated ultrasonic stress while simultaneously ensuring long-term, effective transmission of the ultrasound to the component. To achieve this, a flat connection between the ultrasonic converter and the component is desired.

[0006] For example, it is known to provide the wall of the component with a blind hole and to insert the ultrasonic converter into the blind hole with surface contact, e.g. by providing the blind hole with an internal thread into which the ultrasonic converter is screwed using a coupling thread. If the blind hole is deep enough, the screw connection enables secure mechanical and surface coupling of the ultrasonic converter to the component. However, particularly if the wall thickness of the component is low, sufficiently deep blind holes cannot be provided to ensure mechanical load-bearing capacity and effective transmission of the ultrasound. Other types of coupling, e.g.Clamping, welding, or gluing have not proven effective in practice, as these methods have proven to be inadequate for either the transmission of ultrasound or—especially at higher sound power levels—the mechanical stability, or both. Welding and gluing also complicate the replacement of a potentially defective ultrasonic converter.

[0007] The invention aims to create a method by which an ultrasonic converter can be safely and effectively coupled to a component.

[0008] This goal is achieved with a method for coupling an ultrasonic converter to a component, which comprises the following steps:

[0009] Providing an adapter with a contact surface for the component, an opening extending from its contact surface and an anchoring for the ultrasonic converter;

[0010] Applying the contact surface of the provided adapter to the surface of the component;

[0011] Welding the applied adapter to the component using a circumferential weld seam, leaving at least one gap in the weld seam;

[0012] Introducing potting compound between the contact surface of the adapter and the surface of the component through the opening until potting compound emerges from at least one gap;

[0013] Allowing the applied casting compound to harden; and

[0014] Anchoring the ultrasonic converter to the anchor of the adapter.

[0015] In this process, the weld seam primarily ensures the required mechanical strength of the connection; the cured potting compound contributes to a lesser extent. However, the potting compound ensures a particularly effective ultrasonic coupling between the adapter and the component, between which unavoidable gaps and spaces remain during application and welding, which the potting compound fills. The converter can be permanently or detachably anchored to the adapter. The anchoring can be designed as a flat surface according to requirements by adapting the shape and size of the adapter to the respective needs.

[0016] In an advantageous embodiment, the anchoring is an internal thread in a bore of the adapter, wherein the anchoring step is performed by screwing a coupling thread of the ultrasonic converter into the internal thread. This achieves a detachable, flat anchoring of the ultrasonic converter to the adapter, and via this, the coupling of the ultrasonic converter to the component. An additional contact surface for the ultrasonic converter can be provided on the adapter next to or around the internal thread.

[0017] It is particularly advantageous if the opening in the adapter is a through-hole which, on its side facing away from the contact surface, has the aforementioned internal thread for screwing in the coupling thread. The method further comprises the step of screwing a screw into the internal thread, which step is carried out before the insertion step, wherein the screw is penetrated in the axial direction by a hole through which hole the casting compound is introduced in the insertion step, and the step of unscrewing the screw from the internal thread, which step is carried out after the insertion step and before the hardening step. The adapter is therefore particularly simple in construction and the insertion of the casting compound is particularly secure, while the internal thread is protected by the screw from contamination by casting compound.

[0018] Preferably, the adapter is circularly symmetrical about an axis, and the through-hole is coaxial with the adapter's axis. This allows for a particularly compact, symmetrical design of the adapter, which is also particularly simple due to the circular symmetry. Furthermore, symmetrical ultrasound propagation within the adapter is enabled and a uniform distribution of the potting compound during insertion is promoted, which improves the ultrasonic coupling of the ultrasonic converter to the component via the adapter.

[0019] In an advantageous variant, the method further comprises the steps of roughening and / or degreasing the surface of the component carried out before the application step in order to further improve the adhesion of the potting compound to the surface of the component or the ultrasonic coupling between the contact surface of the adapter and the surface of the component.

[0020] Just like the surface of the component, the contact surface of the adapter is not necessarily flat. In particular, the surface of the component is often curved, e.g. because the component is a cylindrical pipe or silo or a cylindrical heat exchanger or a frustoconical pipe connection piece or a similarly shaped funnel or the like. Therefore, in a favorable embodiment, the method further comprises the step, carried out before the application step, of adjusting the contact surface to the surface shape of the component. As a result of such adjustment, the contact surface of the adapter lies particularly well on the surface because the unavoidable spaces and gaps between the two are particularly small. Consequently, only a small amount of potting compound is required, which favors the ultrasonic coupling between the adapter and the component.Smaller gaps around the circumference of the contact surface also facilitate welding of the adapter to the component and ensure a more secure weld connection.

[0021] In a further advantageous variant, the method further comprises the step of providing the contact surface with a texture, which is carried out before the application step. The texture preferably comprises a spiral bead originating at the opening or a spiral groove originating at the opening. The texture, e.g. an increased roughness, improves the ultrasonic coupling between the adapter and the component and enlarges the surface area of ​​the contact surface for particularly effective ultrasonic transmission. The spiral bead or the spiral groove effect a targeted distribution of the potting compound during introduction, so that unwanted air is effectively displaced from the spaces or gaps between the surface of the component and the contact surface of the adapter.

[0022] It is also advantageous if, during the welding step, several gaps - e.g. three, four or more - are left in the weld seam, evenly distributed around the circumference of the contact surface. This promotes the escape of air from the spaces or gaps between the contact surface of the adapter and the surface of the component, so that the introduction of the casting compound is facilitated and the undesirable retention of air pockets is effectively prevented. The connection of the adapter to the component and, consequently, the ultrasonic coupling are improved.

[0023] Since many applications of ultrasonic excitation involve materials that are processed at elevated temperatures, it is often advantageous to introduce a potting compound during the insertion step that, after the curing step, is temperature-resistant at temperatures of up to 250 °C. Temperature resistance at even higher temperatures may also be desired in some applications and can be achieved by introducing an appropriate potting compound.

[0024] In a preferred embodiment, the potting compound is an epoxy resin. Epoxy resins are available in many variants, differing, among other things, in their hardness when cured and their temperature resistance, so that the resins suitable for the respective applications can be easily selected by the expert. Furthermore, epoxy resins adhere to many different surfaces and, with universal applicability, create a reliable, permanently resilient ultrasonic coupling between the contact surface of the adapter and the surface of the component. The invention is explained in more detail below with reference to an exemplary embodiment illustrated in the accompanying drawings. In the drawings:

[0025] Fig. 1 shows a method according to the invention for coupling an ultrasonic converter to a component in a flow chart;

[0026] Fig. 2 shows an adapter for coupling the ultrasonic converter to the component according to the method of Fig. 1 in a perspective view; Figs. 3a and 3b show the adapter of Fig. 2 in a side view (Fig. 3a) and in a longitudinal section (Fig. 3b) along a section line AA of Fig. 3a;

[0027] Fig. 4 shows the adapter of Fig. 2 and the component during the process of Fig. 1 in a partially sectioned side view; and

[0028] Fig. 5 shows the adapter of Fig. 2 and the component during the process of Fig. 1 in a partially sectioned perspective view.

[0029] Fig. 1 shows a method 1 for coupling an ultrasonic converter to a component 2 (Fig. 4). The purpose of method 1 is to set the component 2 or its wall 2' into high-frequency vibrations with the aid of the ultrasonic converter. These vibrations prevent contaminating particles from undesirably attaching to the component 2 or its wall 2' and prevent particles that have already attached them from becoming loose. Such ultrasonic excitation is used, among other things, in power plants or in industry, in particular in the chemical, petrochemical, construction or paper industries, where the components 2 are, for example, silos, heat exchangers, pipelines, troughs, hoppers, etc., in or through which liquids, pasty substances and mixtures, sand, gravel or the like are conveyed.

[0030] In a step 3 of method 1, an adapter 4 is provided. According to Figs. 2, 3a and 3b, the adapter 4 has a contact surface 5 for the component 2 and an opening 6 extending from its contact surface 5, i.e., the adapter 4 is completely penetrated by the opening 6, starting from its contact surface 5. The opening 6 can extend at a right angle to the contact surface 5 or at an angle to the contact surface 5.

[0031] Furthermore, the adapter 4 has an anchor 7 for the ultrasonic converter. In the example shown, the anchor 7 is an internal thread in a bore 8 of the adapter 4, which is not shown in more detail in Fig. 2. Alternatively, the anchor 7 can be, for example, a flange, a clamp or the like. In the example shown, the bore 8 also forms part of the opening 6. Alternatively, the bore 8 can be a blind bore independent of the anchor 7. Furthermore, an additional, for example, conical and / or flat contact surface 9 for the ultrasonic converter can be provided next to or around the bore 8 or its internal thread on the adapter 4.

[0032] In a subsequent step 10 (Fig. 1), the contact surface 5 of the provided adapter 4 is placed against the surface 11 of the component 2 (here: against the outer surface of its wall 2'). Then, in step 12, the adapter 4 is welded to the component 2. It is understood that for this purpose, the component 2

[0033] - or at least its surface 11 - and the adapter 4 - or at least its contact surface 5 - are made of metal, e.g., aluminum, steel, etc., or a metal alloy. In particular, component 2 and adapter 4 can be made of different metals or metal alloys that can be welded together.

[0034] According to Figs. 4 and 5, the welding 12 is carried out by means of a circumferential weld seam 13, wherein at least one gap 14 - in the example shown, several, e.g., three, four, or more gaps 14 - is left free in the weld seam 13 when the weld seam 13 is set. The weld seam 13 can thus be formed by several spaced-apart weld seam segments

[0035] - or even by a plurality of spaced-apart welding points. In the case of multiple gaps 14, these are optionally distributed evenly over the circumference of the contact surface 5.

[0036] In a subsequent step 15 of the method 1, potting compound (not shown) is introduced through the opening 6 between the contact surface 5 of the adapter 4 and the surface 11 of the component 2 until potting compound emerges from the at least one gap 14. During the introduction 15 of the potting compound, air that has remained in unavoidable spaces or gaps between the contact surface 5 of the adapter 4 and the surface 11 of the component 2 during the welding 12 is displaced by the potting compound through the at least one gap 14.

[0037] The potting compound is allowed to harden in a subsequent step 16. After hardening 16, the potting compound forms a bond between the contact surface 5 of the adapter 4 and the surface 11 of the component 2, which ensures good ultrasonic coupling between the two elements and consequently effective transmission of ultrasound from the adapter 4 to the component 2.

[0038] In a final step 17, the ultrasonic converter (not shown) is anchored to the anchorage 7 of the adapter 4 and is thereby coupled both mechanically and acoustically to the component 2 via the adapter 4. In the example shown, the anchoring 17 is carried out by screwing a coupling thread (not shown) of the ultrasonic converter into the internal thread 7, wherein the coupling thread can be part of the ultrasonic converter or separate from it. In other embodiments not shown here, the ultrasonic converter is e.g. flanged, clamped, etc. during anchoring 17 to the adapter 4.In order to achieve a good acoustic coupling to the component 2, it may be advantageous in some cases to adapt the ultrasonic converter to the shape and size of the adapter 4, so that the ultrasonic propagation inside the adapter 4 and the increased distance of the ultrasonic converter from the component 4 as a result of the intermediately mounted adapter 4 are taken into account in the design of the ultrasonic converter.

[0039] 2 to 5, in the exemplary embodiment shown, the opening 6 in the adapter 4 is a through-hole which, on its side facing away from the contact surface 5, has the anchoring 7 (here: the internal thread for screwing in the coupling thread). In this case, it can be provided that, before step 15 of introducing the casting compound, an optional step 18 is carried out, in which a screw 19, which has a hole 20 passing through it in its axial direction, is screwed into the internal thread 7. The casting compound is introduced through the hole 20 in step 15. After step 15 of introducing the casting compound and before step 16 of allowing the casting compound to harden, in this case the screw 19 is unscrewed from the internal thread 7 in a step 21.

[0040] It is understood that the adapter 4 can have any desired shape, e.g., the shape of a cuboid—or more generally, a parallelepiped—or any other desired shape. Furthermore, the adapter 4 could have multiple openings (or, as here, through-holes) 6, which could optionally extend from the contact surface 5 at different angles. In the illustrated embodiment, however, the adapter 4 is circularly symmetrical about an axis H, and the through-hole 6 is coaxial with the axis H of the adapter 4.

[0041] Depending on the condition of the surface 11 of the component 2, of which only a small section of its wall 2' is shown in Figs. 4 and 5, this surface is roughened and / or degreased or cleaned in another way in one or more optional steps (symbolized in Fig. 1 by a single rectangle 22) in order to achieve better adhesion of the casting compound to the surface 11. This step 22 or these steps are carried out before step 10 of applying the contact surface 5 of the adapter 4 to the surface 11 of the component 2. For degreasing, for example, appropriate organic solvents, aqueous solutions, etc., can be used, as is known to the person skilled in the art. The aerosol product "Spray Cleaner S" from the manufacturer Weicon GmbH & Co. KG has proven to be particularly effective.

[0042] Furthermore, since the component 2 or its wall 2' does not necessarily have to be flat, the contact surface 5 of the adapter 4 can optionally be adapted to the surface shape of the component 2 (step 23 in Fig. 1) - also before step 10 of the application. As shown in the examples in Figs. 4 and 5, the wall 2' of the component 2 is optionally curved, e.g., since the component 2 is a tube with an outer radius R Ä or a funnel, for which the contact surface 5 of the adapter 4 is aligned with the outer radius R Ä the surface 11 of the component 2 is adjusted in step 23 (see Figs. 1 and 3a).

[0043] It is understood that this alignment 23 does not need to be performed with particularly high precision, since the potting compound bridges any remaining gaps or spaces between the contact surface 5 and the surface 11. However, the smaller such gaps or spaces are, the more effective the ultrasonic coupling between the adapter 4 and the component 2.

[0044] In a further optional step 24, which is also carried out before step 10 of application, the contact surface 5 of the adapter 4 is provided with a texture, e.g. roughened, embossed or the like. The texture can be a spiral bead (not shown) originating at the opening 6 or a spiral groove originating at the opening 6 or can additionally comprise these. If several openings 6 originate from the contact surface 5, multi-start spiral beads or grooves can also be provided. Alternatively, beads or grooves could originate from the opening(s) 6 in a star shape, for example, instead of a spiral shape. For example, the gaps 14 in the weld seam 13 are also provided at those points at which the beads or grooves open into the circumference of the contact surface 5.As is known to those skilled in the art, various potting compounds can be considered, which are introduced in step 15 between the contact surface 5 of the adapter 4 and the surface 11 of the component 2. These should not be too soft, so as not to excessively dampen the ultrasound emitted by the ultrasonic converter, and not too hard, so as not to be excessively brittle. Epoxy resin, for example, has proven suitable as a potting compound.

[0045] If desired, a potting compound can be used and introduced in step 15. This compound, after curing (step 16), is temperature-resistant at temperatures of up to 180°C, 250°C, or higher. For example, the two epoxy resin adhesives of the brands "Easy-Mix HT 180" and "Easy-Mix HT 250" from the manufacturer Weicon GmbH & Co. KG have proven to be particularly suitable; they are temperature-resistant up to 180°C and 250°C, respectively, when cured. Suitable potting compounds, epoxy resins, or adhesives are also available for lower or higher temperatures, for example the acrylate structural adhesive of the brand "Easy-Mix RK-7100" from the same manufacturer for the temperature range of -55°C to 125°C.

[0046] It is understood that the sequence of steps of method 1 shown in Fig. 1 is not mandatory, but—unless dictated by other steps or expressly stated otherwise—a different sequence may be provided. In particular, some of the optional steps symbolized by dashed rectangles may be arranged differently in relation to each other and to the mandatory steps of method 1 symbolized by solid rectangles than shown in Fig. 1.

[0047] The invention is not limited to the embodiments shown, but includes all variants, modifications and combinations thereof that fall within the scope of the appended claims.

Claims

Patent claims:

1. A method for coupling an ultrasonic converter to a component (2), comprising the steps: Providing (3) an adapter (4) with a contact surface (5) for the component (2), an opening (6) extending from its contact surface (5) and an anchoring (7) for the ultrasonic converter; Applying (10) the contact surface (5) of the provided adapter (4) to the surface (11) of the component (2); Welding (12) the applied adapter (4) to the component (2) by means of a circumferential weld seam (13) while leaving at least one gap (14) in the weld seam (13); introducing (15) potting compound between the contact surface (5) of the adapter (4) and the surface (11) of the component (2) through the opening (6) until potting compound emerges from the at least one gap (14); Allowing the applied casting compound to harden (16); and Anchoring (17) of the ultrasonic converter to the anchoring (7) of the adapter (4).

2. Method according to claim 1, wherein the anchoring (7) is an internal thread (7) in a bore (8) of the adapter (4), and wherein the step (17) of anchoring is carried out by screwing a coupling thread of the ultrasonic converter into the internal thread (7).

3. The method according to claim 2, wherein the opening (6) of the adapter (4) is a through hole (6) which has on its side facing away from the contact surface (5) the internal thread (7) for screwing in the coupling thread, further comprising the step (18) of screwing a screw (19) into the internal thread (7) carried out before the step (15) of insertion, wherein the screw (19) is penetrated in the axial direction by a hole (20), through which hole (20) the casting compound is introduced in the step (15) of insertion, and the step (16) of insertion hardening step (21) of unscrewing the screw (19) from the internal thread (7).

4. Method according to claim 3, wherein the adapter (4) is circularly symmetrical about an axis (H) and the through-bore (6) is coaxial to the axis (H) of the adapter (4).

5. Method according to one of claims 1 to 4, further comprising the steps (22) of roughening and / or degreasing the surface (11) of the component (2) carried out before the step (10) of applying.

6. Method according to one of claims 1 to 5, further comprising the step (23) of adapting the contact surface (5) to the surface shape of the component (2) carried out before the step (10) of applying.

7. The method according to any one of claims 1 to 6, further comprising the step (24) of providing the contact surface (5) with a texture, carried out before the step (10) of applying, wherein the texture preferably comprises a spiral bead originating at the opening (6) or a spiral groove originating at the opening (6).

8. Method according to one of claims 1 to 7, wherein in the welding step (12) a plurality of gaps (14) evenly distributed over the circumference of the contact surface (5) are left free in the weld seam (13).

9. Method according to one of claims 1 to 8, wherein in the step (15) of introducing a potting compound is introduced which is temperature-resistant at temperatures of up to 250°C after the step (16) of curing.

10. The method according to any one of claims 1 to 9, wherein the potting compound is an epoxy resin.

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