Vibration sensor and method for balancing a vibration sensor

Abstract

A vibration sensor comprises a mechanically oscillatable unit (1) having an outer tube (10) and an inner tube (11). By means of successive recesses (110, 20, 30) in the vibration sensor, a compensation part (4) can be introduced into and / or changed in the mechanically oscillatable unit (1). The invention also relates to a method for balancing a vibration sensor.

Description

Technical Field

[0001] This invention relates to a vibration sensor. Furthermore, this invention relates to a method for balancing the vibration sensor. The vibration sensor is used, for example, to determine and / or monitor process variables of a medium. Process variables are, for example, fill level, density, or viscosity, and the medium is, for example, a liquid, gas, or bulk article. Background Technology

[0002] A known type of vibration sensor in the prior art has a mechanically oscillating unit that is excited by a transducer device to perform mechanical oscillations. In addition to its function as an excitation unit, the transducer device also functions as a receiving unit. Therefore, the oscillations modulated by the interaction with the medium are received and evaluated by the transducer device. In this case, the transducer device uses, for example, a piezoelectric element that converts between electrical signals and mechanical oscillations. What is measured is, for example, the change in oscillation frequency or amplitude when the mechanically oscillating unit changes from an uncovered state to a state covered by the medium. This makes it possible, for example, to monitor the fill level of the medium in a container.

[0003] It is known that mechanically oscillating units can take the form of an oscillating fork with two serrated teeth, or simply a membrane or even a single rod. The subject of these devices is that as little oscillating energy as possible should be transferred to the retainer of the mechanically oscillating unit. In this case, the retainer is the area through which the device (especially the mechanically oscillating unit) is mounted at the measurement point. For example, if monitoring the fill level of a medium in a container is desired, the mechanically oscillating unit is most often partially introduced and fixed in the measurement space via a port in the container wall, thus being fixed inside the container. If the mechanically oscillating unit transfers mechanical energy to the retainer, other equipment components mechanically connected to the container, or even processes occurring within the container in a given case, may be affected. Resonance in the container could even be induced. To prevent this, the mechanically oscillating unit must be balanced so that no oscillating energy flows out through the retainer. For this purpose, the serrated teeth of the oscillating fork are balanced relative to each other, for example. In the case of a single rod, balancing is also known. In this respect, the following fact is utilized: although it looks like a single rod from the outside, it is generally composed of two parts, namely, an inner tube and an outer tube, each of which is adapted such that its oscillation cancels out the oscillation of its mating part at the retainer.

[0004] In DE 10 2004 011 377 A1, a single rod is connected to an adjusting unit, the stiffness of which is electrically set. The balancing of the single rod occurs in DE 10 2004 009 495 A1 and DE 10 2012 103 165 A1 or DE 196 51 362 C1 because, in each case, additional components are introduced into the inner tube of the single rod. In DE 102015 122 648 A1, the oscillating behavior of the single rod is set by the extent to which the inner oscillating body extends inward into the outer tube.

[0005] It is obvious that the construction used for balancing is relatively complex. This comes with increased cost and complexity, which can also lead to problems. Summary of the Invention

[0006] One object of the present invention is to simplify the balancing of a single rod used as a mechanically oscillating unit.

[0007] The present invention achieves its purpose by including a vibration sensor comprising a single rod and a method for balancing the vibration sensor, and in particular a mechanically oscillating unit.

[0008] This objective is achieved by a vibration sensor comprising a mechanically oscillable unit, a transducer device, a housing, and a compensation component. The transducer device excites the mechanically oscillable unit to perform mechanical oscillations and / or receives mechanical oscillations from the mechanically oscillable unit. The mechanically oscillable unit comprises an outer tube, an inner tube, and a terminal unit. The outer tube includes an inner space, a first end, and a second end. The inner tube is disposed within the inner space of the outer tube. The outer tube is connected to the housing via the first end. The inner space of the outer tube is defined at the second end via the terminal unit. The compensation component is at least partially disposed within and / or borders the inner space of the outer tube. The compensation component is mechanically coupled to the outer tube and / or to the inner tube. The vibration sensor includes a transverse channel through which the compensation component can be introduced and / or modified.

[0009] The vibration sensor of the present invention includes a mechanically oscillating unit and a transducer device. In this case, the transducer device converts between an electrical signal and the oscillation of the mechanically oscillating unit. A housing and a compensation component are further present. The housing also surrounds, for example, the electronics of the sensor. The mechanically oscillating unit is connected to the housing. Specifically, one end of the outer tube of the mechanically oscillating unit is connected to the housing. The opposite end is connected to a terminal unit. The outer tube and the terminal unit can be a single piece. The terminal unit and the outer tube enclose an inner space, in which the inner tube of the mechanically oscillating unit is located. The compensation component is used to compensate for the mechanically oscillating unit and is at least partially or completely located in the inner space of the outer tube and / or arranged to interface with the inner space of the outer tube. Furthermore, the compensation component is mechanically coupled to the outer tube and / or the inner tube such that the compensation component influences the oscillation behavior. The vibration sensor includes a transverse channel through which the compensation component can be introduced and / or modified. Therefore, the compensation component can be introduced and / or modified via the channel. In terms of modifications, for example, the mass of the compensation component can be changed.

[0010] In one embodiment, the transverse channel opens at the end of the outer tube furthest from the terminal unit. In this embodiment, the channel thus extends from the opening into the interior of the vibration sensor.

[0011] The following examples relate to the location of the channel by discussing which components form the channel.

[0012] One embodiment of the vibration sensor specifies that the inner tube has a transverse channel. Therefore, the inner tube in this embodiment is essentially implemented as a hollow cylinder.

[0013] A supplemental or alternative embodiment of the vibration sensor specifies that the transducer device has a transverse channel.

[0014] A supplementary or alternative embodiment of the vibration sensor specifies that the housing has a transverse channel. In a supplementary embodiment, the transverse channel is located at the end of the housing that connects to the mechanically oscillating unit. Therefore, in this embodiment, after the vibration sensor is installed, this end of the housing faces the medium.

[0015] A supplemental or alternative embodiment of the vibration sensor includes an outer tube that is substantially cylindrical, and a terminal unit that closes the outer tube at the second end. Therefore, depending on orientation, the terminal unit can be a cap or a base plate of the outer tube.

[0016] A supplementary or alternative embodiment of the vibration sensor specifies that the transducer device has at least one piezoelectric element. In a supplementary embodiment, the transducer device is formed of at least one annular piezoelectric element.

[0017] A supplemental or alternative embodiment of the vibration sensor includes a recess in the terminal unit, and the compensation member is at least partially disposed within the recess of the terminal unit. In this embodiment, the terminal unit thus has, for example, a blind hole that at least partially receives the compensation member.

[0018] A supplemental or alternative embodiment of the vibration sensor specifies that the compensation component is at least partially composed of a hardenable fluid, and the fluid is configured such that its viscosity depends on the shear force acting on it. Preferably, the fluid is introduced into the mechanically oscillating unit in an unhardened state via the channel and hardens there, for example, from the outside or by its own application. The fluid preferably has the characteristic that it becomes low in viscosity when shear force acts upon it, thus exhibiting pseudoplasticity or shear thinning. However, if no shear force is present, the fluid has high viscosity. Preferably, the fluid is configured such that, under given conditions, it can be removed from the mechanically oscillating unit.

[0019] Complementary or alternative embodiments of the vibration sensor include a compensation component at least partially composed of fixable powder. Preferably, the powder is introduced into the mechanically vibratory unit and fixed therein under equilibrium conditions, in which the powder is transformed into a solid unit or into a unit connected to a larger component. The fixing of the powder is performed, for example, by laser welding, by applying voltage, or by, for example, by compression or by a chemical reaction initiated by a suitable catalyst.

[0020] A supplementary or alternative embodiment of the vibration sensor specifies that the compensation component is at least partially formed by a mass element and a fastening device, the mass element being fixed in the inner space of the outer tube via the fastening device having at least two stable deformation states, and the fastening device—preferably by applying mechanical force—transferring from one deformation state to another. In this embodiment, the effect of the mass element depends on its position relative to the mechanically oscillating unit, and therefore on its position relative to the sub-components (i.e., the inner and outer tubes). For this purpose, the mass element fixed in the inner space by such a fastening device can present at least two different deformation states, and therefore, especially not a state that automatically springs back from one state to another due to elastic deformation. These two deformation states are characterized in that, in each case, the mass element presents a different position within the inner space. Thus, in one embodiment, each deformation state is located at a different position of the mass element along the longitudinal axis of the mechanically oscillating unit. The traversing channel allows the mechanically oscillating unit to be balanced, for example, by applying mechanical force to the mass element and / or the fastening device, causing a transition from one deformation state to another. Therefore, continuous deformation from one state to another occurs in particular.

[0021] Furthermore, the present invention achieves this objective through a method for balancing a vibration sensor, wherein the vibration sensor includes a mechanically oscillating unit, and wherein the method includes the steps of: introducing a compensation component into the mechanically oscillating unit via a transverse channel of the vibration sensor and / or altering the compensation component in the mechanically oscillating unit.

[0022] According to the present invention, balancing a vibration sensor having a mechanically oscillating unit is achieved by introducing a compensation component into the mechanically oscillating unit and / or altering the compensation component already in the mechanically oscillating unit via a transverse channel of the vibration sensor. Therefore, the vibration sensor has a transverse channel that allows the introduction of a compensation component into the mechanically oscillating unit and / or modification of the compensation component already in the mechanically oscillating unit. For example, the balancing is performed during the manufacture of the vibration sensor, during installation at the application site, or as part of adaptation during application. In this case, depending on the embodiment or application type, the transverse channel is reversibly or irreversibly closed after the balancing is completed.

[0023] An embodiment of the method includes introducing a tool in the form of a hollow needle (preferably temporarily) into the channel, and introducing the compensation component into the mechanically oscillating unit through the hollow needle. In this embodiment, the hollow needle is introduced into the channel, and the compensation component is guided within the hollow needle to reach the mechanically oscillating unit. This facilitates the process and also prevents the compensation component from being positioned in an undesirable location.

[0024] Alternative or supplementary embodiments of the method specify that the introduced compensating component is acted upon to harden it. In this embodiment, the compensating component is located within the mechanically vibrating unit and is initially in a liquid or powder state, and therefore not in a completely solid form. Correspondingly, it is specified that the hardening of the compensating component occurs, for example, thermally, mechanically via the introduction of UV light, via a chemical reaction, or via the application of an electric or magnetic field.

[0025] Alternative or supplementary embodiments of the method include introducing (preferably temporarily) a tool in the form of an interaction device into the transverse channel and applying a mechanical force to the compensation member via the interaction device. In this embodiment, the compensation member is configured to respond to the mechanical force. This is, for example, a change in position or compression of the compensation member. In this case, the compensation member may already be present in the mechanically oscillating unit, for example, before the balancing is performed. Alternatively, during the balancing process, the compensation member may first be introduced (e.g., via the aforementioned hollow needle) and then acted upon via the interaction device.

[0026] Alternative or supplementary embodiments of the method specify that the method further includes the steps of: mechanically coupling the mechanically oscillating unit (preferably temporarily) to the retainer, and introducing sufficient compensation components into the mechanically oscillating unit and / or altering the compensation components in the mechanically oscillating unit such that the mechanical oscillation of the mechanically oscillating unit substantially has no force and / or torque transmission from the mechanically oscillating unit to the retainer. In this embodiment, the mechanically oscillating unit is temporarily or continuously connected to the retainer. In this case, the retainer may be a tool used to manufacture the vibration sensor. Alternatively, the retainer is part of the process that the vibration sensor should monitor. Therefore, it may involve, for example, the wall of a container. The goal of the balancing is to transfer as little energy from the mechanically oscillating unit to the retainer as possible. To this end, the compensation components are correspondingly acted upon, because, according to embodiments, a suitable amount of material of the compensation components is introduced into the mechanically oscillating unit, or such material is correspondingly affected.

[0027] Accordingly, the detailed description and explanation of the method also apply to the vibration sensor, and vice versa, so that repetitions are omitted here. Attached Figure Description

[0028] The invention will now be explained in more detail with reference to the accompanying drawings, which are shown below: Figure 1 A schematic cross-section through a first embodiment of the vibration sensor. Figure 2 A cross-section of the second embodiment of the vibration sensor. Figure 3 A cross-section of a third embodiment of a vibration sensor having a first deformation state with a compensation component. Figure 4 Figure 3 A cross-section of a portion of the vibration sensor shows the second deformation state of the compensation component, and Figure 5 The third deformation state of the compensation component. Detailed Implementation

[0029] Figure 1 A first embodiment of a vibration sensor during balancing is shown.

[0030] The vibration sensor includes a mechanically oscillating unit 1, which is excited by a transducer device 2 to perform oscillations. In the illustrated embodiment, the transducer device 2 also receives mechanical oscillations from the mechanically oscillating unit 1 and converts them into electrical signals. Based on the received signals, it can then be confirmed, for example, by an electronic evaluation unit (not shown), whether a fill level has been reached or what characteristics the medium possesses, wherein the mechanically oscillating unit 1 is in contact with the medium.

[0031] The mechanically oscillating unit 1 is implemented as a single rod. This is constituted by a cylindrical inner tube 11 within an inner space 100 of an equally cylindrical outer tube 10. The outer tube 10 has two ends 101 and 102. The outer tube 10 is connected to the housing 3 via the first end 101. The housing 3 encloses the transducer device 2 and other (not shown) components of the vibration sensor. The second end 102 is closed by a terminal unit 12, which may also be referred to as a cover or base plate. The inner tube 11 is located within the inner space 100, which is sealed and isolated from an external medium (not shown).

[0032] As shown in the figure, the transducer device 2 is firmly fixed relative to the housing 3.

[0033] For balance, the vibration sensor has a transverse channel inside, which is composed of a transverse channel 110 in the inner tube 11, a transverse channel 30 in the housing 3, and a transverse channel 20 in the transverse transducer device 2. Channels 20, 30, and 110 are arranged one after another along the axial direction to form the entire transverse channel, into which a hollow needle-shaped tool 5 is introduced.

[0034] The compensating component 4, which is still able to flow through the hollow needle 5, is introduced into the inner space 100 of the outer tube 10 to change its mass and thus its oscillating behavior relative to the inner tube 11. Once sufficient material for the compensating component 4 has been introduced, the hollow needle 5 is removed and hardening begins so that the compensating component 4 cannot be displaced during oscillation.

[0035] Figure 2 The implementation of the vibration sensor is similar to Figure 1 Therefore, only the differences will be explained.

[0036] The diagram shows the state where the tool used to introduce and act on the compensation member 4 has been removed from the transverse channel. In this embodiment, the compensation member 4 is located in the recess 120 of the terminal unit 12. To accommodate the recess 120, the terminal unit 12 is significantly thicker than [previous material]. Figure 1 The terminal unit in the embodiment. The compensation member 4 is located in the recess 120, which is implemented as a blind hole, and is connected to the inner space 100 of the outer tube 10. Therefore, in this embodiment, a portion of the terminal unit 12 (i.e., a portion of the recess 120) is at least partially replaced by the material of the compensation member 4.

[0037] for Figure 1 and Figure 2 In the embodiments of the balance, in each case, material is introduced into the inner space 100 of the outer tube 10 or is connected to the inner space 100 of the outer tube 10. Figure 3 The variant involves compensation component 4, which is already located in the mechanically oscillating unit 1.

[0038] for Figure 3 Examples, such as in Figure 2 As in the same case, only discuss with Figure 1 The difference between the variants.

[0039] The compensation component 4 is located on the inner side of the outer tube 10 and consequently within the inner space 100 of the outer tube 10. In this case, the compensation component 4 consists of a mass element 40 and a fastening device 41. In this case, the fastening device 41 is used to connect the mass element 40 to the outer tube 10. The compensation component 4 is located outside the movement trajectory of the inner tube 11, facing the terminal unit 12.

[0040] In this configuration, the vibration sensor is connected to the retainer 6 via the housing 3, which is, for example, the wall of a container. A tool 5, in the form of an interaction device, is introduced into the transverse channel of the vibration sensor, through which mechanical force is applied to the compensation member 4. In this configuration, the compensation member 4 is affected such that the vibration sensor does not transmit force and / or torque to the retainer 6, meaning that the force and torque of the oscillations of the outer tube 10 and the inner tube 11 directly cancel each other out. To detect this, for example, a force sensor 7 is located on the retainer 6.

[0041] Figure 3 The first deformed state of the compensation component 4 is shown. Importantly, the mass element 40 and the fastening device 41 are located at the same height along the longitudinal axis of the mechanically oscillating unit 1.

[0042] Figure 4 A second deformed state is shown, in which the mass element 40 is arranged further away from the terminal unit 12. (Comparison of interaction devices) Figure 3 This displacement of the mass element 40 can be achieved using, for example, a magnet.

[0043] Figure 5 A third deformation state is also shown, in which the mass element 40 has moved in the direction of the terminal unit 12. Each deformation state has a different moment of inertia.

[0044] List of reference numerals

[0045] 1 Mechanically oscillating unit

[0046] 2. Transducer device

[0047] 3. Shell

[0048] 4. Compensation components

[0049] 5 tools

[0050] 6. Holder

[0051] 7 Force Sensors

[0052] 10 outer tubes

[0053] 11 Inner tube

[0054] 12 terminal units

[0055] 20 Transducer unit cross passage

[0056] 30 Transverse passage of the shell

[0057] 40 mass components

[0058] 41 Fastening device

[0059] 100 interior space

[0060] 101 First end

[0061] 102 Second end

[0062] 110 Transverse passage of the inner tube

[0063] 120 Recess of terminal unit

Claims

1. A vibration sensor, comprising: Mechanically oscillating unit (1), Transducer device (2), Shell (3), and Compensation component (4), The transducer device (2) excites the mechanically oscillable unit (1) to perform mechanical oscillation, and / or receives mechanical oscillation from the mechanically oscillable unit (1). The mechanically oscillable unit (1) includes an outer tube (10), an inner tube (11), and a terminal unit (12). The outer tube (10) includes an inner space (100), a first end (101), and a second end (102). The inner tube (11) is arranged in the inner space (100) of the outer tube (10). The outer tube (10) is connected to the housing (3) via the first end (101). The inner space (100) of the outer tube (10) is defined at the second end (102) via the terminal unit (12). The compensation component (4) is at least partially disposed within the inner space (100) of the outer tube (10) and / or adjoins the inner space (100) of the outer tube (10). The compensation component (4) is mechanically connected to the outer tube (10) and / or to the inner tube (11), and The vibration sensor includes transverse channels (110, 20, 30), and the compensation component (4) can be introduced and / or altered through the transverse channels.

2. The vibration sensor according to claim 1, in, The inner tube (11) includes a transverse channel (110), And / or The transducer device (2) includes a transverse channel (20). And / or The housing (3) includes a transverse channel (30).

3. The vibration sensor according to claim 1 or 2, in, A recess (120) exists in the terminal unit (12), and The compensation component (4) is at least partially disposed in the recess (120) of the terminal unit (12).

4. The vibration sensor according to any one of claims 1 to 3, in, The compensation component (4) is at least partially composed of a hardenable fluid, and The fluid is configured such that its viscosity depends on the shear force acting on it.

5. The vibration sensor according to any one of claims 1 to 4, in, The compensation component (4) is at least partially composed of powder that can be fixed.

6. The vibration sensor according to any one of claims 1 to 5, in, The compensation component (4) is at least partially formed by a mass element (40) and a fastening device (41). The mass element (40) is fixed in the inner space (100) of the outer tube (10) via the fastening device (41). The fastening device (41) has at least two stable deformation states, and The fastening device (41) is preferably used to change from one deformation state to another by applying mechanical force.

7. A method for balancing vibration sensors. in, The vibration sensor includes a mechanically oscillating unit (1). The method includes the following steps: The compensation component (4) is introduced into the mechanically oscillating unit (1) via the transverse channels (110, 20, 30) of the vibration sensor and / or the compensation component (4) in the mechanically oscillating unit (1) is changed.

8. The method according to claim 7, in, A hollow needle-shaped tool (5) is introduced (preferably temporarily) into the transverse channels (110, 20, 30), and wherein the compensation component (4) is introduced into the mechanically oscillating unit (1) via the hollow needle (5).

9. The method according to claim 7 or 8, in, A tool (5) in the form of an interaction device is introduced (preferably temporarily) into the transverse channels (110, 20, 30), and mechanical force is applied to the compensation member (4) through the interaction device (5).

10. The method according to any one of claims 7 to 9, in, The method further includes the following steps: The mechanically oscillating unit (1)—preferably temporarily—is mechanically connected to the retainer (6), and Sufficient compensation components (4) are introduced into the mechanically oscillating unit (1) and / or the compensation components (4) in the mechanically oscillating unit (1) are modified such that the mechanical oscillation of the mechanically oscillating unit (1) has substantially no transmission of force and / or torque from the mechanically oscillating unit (1) to the retainer (6).

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