Attachment for connecting to a level gauge for measuring the fill level of a medium in a container

Description

[0001] The invention is based on an attachment for connection to a level measuring device for measuring the level of a medium in a container, and on a system comprising a level measuring device for measuring the level of a medium in a container and at least one attachment, wherein the level measuring device has a control and evaluation unit for generating a measurement signal and a process connection element, wherein the process connection element has a transmission element on the medium side, wherein the transmission element is at least partially permeable to the measurement signal.

[0002] When it is stated that the process connection element has a transmission element on the medium side, this means that the transmission element is located on the medium side during operation or when installed. According to one embodiment, the measurement signal is a radar signal, and the level measuring device is a free-radiating radar level measuring device. The measurement signal can be emitted continuously or in pulsed form during operation. Free-radiating level measuring devices can be used in a variety of practical situations.

[0003] Depending on the measurement situation, various properties of the measurement signals emitted by the level measuring devices are advantageous. Of particular relevance is the aperture angle of the emitted signal, which defines the area of ​​the medium considered for determining the level. Wide measurement signals with large aperture angles have the advantage of covering a large area of ​​the medium to determine the level. On the other hand, obstructions in the vessel during operation can also easily interfere with the measurement signal.

[0004] Therefore, depending on the situation, it is also advantageous if the measurement signal has the smallest possible aperture angle. This type of measurement signal configuration is used in practice, for example, in narrow, tall containers. Lens antennas, in particular, which transmit a measurement signal in the 80 GHz range, can realize a measurement signal with an aperture angle of just a few degrees.

[0005] Level measuring devices are known, for example, from the documents US 2015 / 241261 A1, DE 10 2017 124996 A1, US 2019 / 353514 A1, US 2016 / 320225 A1 and CN 109 713 452 A.

[0006] The invention is based on the object of providing a system comprising a level measuring device and an attachment so that the level measuring device can be used particularly flexibly. Furthermore, the invention is also an object of providing an attachment for producing a system according to the invention.

[0007] According to a first teaching, the above-mentioned object is achieved by a system as mentioned above comprising a level measuring device and at least one attachment in that the at least one attachment is connected to the process connection element, wherein the at least one attachment has an attachment lens on the medium side for coupling the measuring signal into the container, wherein the attachment lens is designed in such a way and is arranged behind the transmission element in the propagation direction of the measuring signal in such a way that it changes the aperture angle of the measuring signal.

[0008] For example, the attachment lens can widen the measurement signal, i.e. increase the aperture angle, or focus the measurement signal, i.e. reduce the aperture angle.

[0009] According to the invention, it was recognized that the directional characteristic or the aperture angle of the measuring signal can be influenced by an attachment in front of the transmission element. The directional characteristic realized by the level measuring device can be adapted to a specific measuring situation by using the attachment. This allows one measuring device or a plurality of level measuring devices with the same design to be optimized for different measuring situations.

[0010] If the attachment is interchangeable, i.e. detachably connected to the level measuring device, a single level measuring device can be combined with different attachments and thus, for example, optimized for different measuring situations even after installation in a container.

[0011] The system according to the invention can therefore be used in a particularly flexible manner, since the measuring device can be optimized for different applications without having to make structural changes to the measuring device.

[0012] In principle, the transmission element and the attachment lens are coordinated to shape the measurement signal. In detail, the combination of these elements is also designed to avoid creating a focal point in the container, ensuring that the desired measurement area is fully illuminated.

[0013] According to a first embodiment, the transmission element is designed as a lens or as a window. If the transmission element is designed as a lens, then according to one embodiment the measurement signal shaped by the lens is optimized for a measurement situation, in particular with regard to the aperture angle of the measurement signal. For example, a measurement signal with a frequency of approximately 80 GHz and a lens diameter of approximately 70 mm can have a particularly small aperture angle of approximately 4°. Alternatively, a measurement signal with a frequency of approximately 80 GHz and a lens diameter of approximately 40 mm can have an aperture angle of approximately 8°, whereby a larger measurement range can be detected. It is also conceivable for the lens to shape the measurement signal in such a way that the aperture angle has a medium value.

[0014] The use of a window that allows the measurement signal to pass through is also conceivable here.

[0015] According to another particularly preferred embodiment, the connection between the process connection element and the attachment is designed as a detachable connection, wherein the connection is designed as a force-locking and / or form-locking connection, wherein the connection is preferably realized via a thread, a snap-in connection, or a flange connection. This embodiment has the advantage that the at least one attachment can be connected to the process connection element in a mechanically secure and pressure-tight manner and can also be replaced.

[0016] For example, the process connection element has an external thread, and the attachment has a matching internal thread, via which the attachment is arranged on the process connection element. According to an alternative embodiment, the process connection element has an internal thread, and the attachment has a matching external thread, via which the attachment is arranged on the process connection element.

[0017] Alternatively, the connection between the process connection element and the attachment is designed as a permanent connection, wherein the permanent connection is preferably designed as a material-to-material connection.

[0018] According to a further embodiment, a holder is provided, whereby the attachment can be connected to the container via the holder. In addition to the connection to the process connection element, the attachment can also be positioned in the container using a corresponding holder.

[0019] According to a further preferred embodiment, the attachment is designed as an adapter. Particularly preferably, the adapter can be connected both to the process connection element of the level measuring device and to a process connection, in particular a container connection.

[0020] In particular, the adapter is designed such that it can be connected to both the process connection element and a container connection via a threaded connection. For this purpose, the adapter has two threads, particularly preferably two different threads.

[0021] For example, the adapter adapts from a GAS thread to an NPT thread. Alternatively, the adapter adapts from an NPT thread to a GAS thread.

[0022] In addition, the adapter can also be designed in such a way that it can be connected to the container connection via a bayonet connection.

[0023] The adapter design therefore offers the advantage that a level gauge can be mounted on various containers with different container connections. Overall, this design further improves the flexible placement of the level gauge.

[0024] According to a next preferred embodiment, the at least one attachment has an interior space, wherein the interior space is at least partially hollow. In particular, the area between the transmission element and the attachment lens is designed as a hollow space. During operation, the measurement signal is transmitted from the transmission element to the attachment lens via this hollow space.

[0025] According to a next embodiment, at least one dielectric material for guiding and / or adapting the measurement signal is present in the interior of the at least one attachment.

[0026] In addition, according to a further embodiment, a horn structure can be present in the interior of the attachment to guide the measurement signal.

[0027] A further advantageous embodiment of the system is characterized in that the transmission element is designed as a lens, the diameter of this lens being smaller than the diameter of the attachment lens.

[0028] This design allows the aperture angle of the measurement signal to be focused particularly advantageously, since a large aperture area is known to be necessary to achieve a particularly small aperture angle of the measurement signal. This design is therefore particularly advantageous when interfering internals protrude into the vessel. This ensures that the measurement signal is not disrupted by such internals. This design is also advantageous when a process medium is to be monitored in a long, narrow vessel.

[0029] A further embodiment is characterized in that the transmission element is designed as a lens, the diameter of this lens being larger than the diameter of the attachment lens.

[0030] This design, for example, allows the aperture angle of the measurement signal passing through the transmission element to be increased, thus also covering a larger area of ​​the medium. This design is advantageous when the largest possible measurement area of ​​the medium needs to be illuminated.

[0031] A further embodiment is characterized in that the transmission element is designed as a lens, the diameter of this lens being substantially identical to the diameter of the attachment lens.

[0032] Alternatively or additionally, the attachment lens may also differ from the transmission element in shape, in particular in the radius of curvature and / or in the material.

[0033] If a cavity is present at least partially in the interior of the at least one attachment, it is advantageous if an overpressure relief device is provided in the area of ​​the cavity to limit the overpressure in the attachment. This configuration is particularly suitable for measurements under high process pressures.

[0034] Particularly preferably, the overpressure protection device is designed in such a way that it triggers when a limit value for the pressure in the attachment is exceeded, wherein the limit value is lower than the maximum permissible process pressure.

[0035] According to one embodiment, the limit value is approximately one third of the process pressure.

[0036] According to a further embodiment, the overpressure protection device is designed as a predetermined breaking point of the attachment housing. Alternatively, the overpressure protection device can also be implemented by any other known and suitable overpressure protection device.

[0037] The presence of an overpressure protection device ensures better protection, especially for the electronics and wiring of the measuring device.

[0038] Particularly preferably, the overpressure protection device is arranged on the attachment in such a way that it is not arranged inside the container during operation, i.e. in the assembled state.

[0039] According to a further embodiment, the transmission element and / or the attachment lens are designed as a seal. If the transmission element and the attachment lens are designed as a seal, this design ensures the requirements for a double seal for use in potentially explosive applications. The combination of a double seal with an overpressure relief device ensures a particularly high level of protection for the electronics and cabling of the control and evaluation unit.

[0040] According to a further embodiment, the add-on lens is designed and matched to the transmission element in such a way that the add-on lens additionally changes the propagation direction of the measurement signal. Particularly preferably, the transmission element according to this embodiment is also designed as a lens. For example, the add-on lens is designed and matched to the transmission element in such a way that the add-on lens reduces the aperture angle of the measurement signal, for example to approximately 9°, and pivots the propagation direction by a few degrees, for example by approximately 6°. The description and / or determination of the geometric design of the individual antenna elements, such as the transmission element designed as a lens and / or the add-on lens, is particularly preferably simplified by the assumption that the propagation of the electromagnetic waves is diffraction-free, so that the beam path can be observed instead of the phase fronts.Consequently, a propagating wave can be described particularly easily by rays in the direction of propagation.

[0041] This design has the advantage that an oblique installation position of the antenna for generating and emitting the measuring signal can be compensated or that the area to be illuminated in the container of a measuring device can be adjusted particularly flexibly and / or changed, for example, by means of various attachments.

[0042] According to a further particularly preferred embodiment, a plurality of attachments is assigned to the level measuring device, with which different aperture angles of the measuring signal and / or different changes in direction of propagation of the measuring signal are realized, in particular wherein the individual attachments differ in the shape of the attachment lens and / or in the size of the attachment lens and / or in the material of the attachment lens and / or in the distance of the attachment lens to the transmission element in the connected state.

[0043] When it is stated that a level measuring device is assigned multiple attachments, this means that a plurality of different attachments are designed in such a way that they can be connected to the process connection element of the level measuring device. Such a connection does not occur simultaneously; rather, the individual attachments can be connected to the process connection in different measuring situations.

[0044] This system, consisting of a level measuring device and a number of attachments, each of which optimizes the measuring device for different measuring situations, has the advantage that the level measuring device can be used particularly flexibly for different applications.

[0045] According to a second teaching, the present invention relates to an attachment for connection to a level measuring device for producing one of the previously described systems. For this purpose, the attachment is designed according to one of the previously described embodiments.

[0046] There are now numerous possibilities for designing and developing the system and attachment according to the invention. Reference is made to the claims subordinate to the independent patent claims and to the description of the following exemplary embodiments together with the drawings. The drawings show: Fig. 1 shows a first embodiment of a system according to the invention, Fig. 2 shows a further embodiment of a system according to the invention, Fig. 3 shows a further embodiment of a system according to the invention, Fig. 4 shows a further embodiment of a system according to the invention, Fig. 5 shows a further embodiment of a system according to the invention, Fig. 6 shows a further embodiment of a system according to the invention, Fig. 7 shows a further embodiment of a system according to the invention and Fig. 8 shows a further embodiment of a system according to the invention arranged on a container.

[0047] Fig. 1shows a first embodiment of a system 1 comprising a level measuring device 2 for measuring the level of a medium in a container and an attachment 3, wherein the level measuring device 2 has a control and evaluation unit 4 and a process connection element 5, wherein the process connection element 5 has a transmission element 6 in the form of a lens 7 on the medium side, wherein the lens 7 is at least partially permeable to the measurement signal generated by the control and evaluation unit 4.

[0048] An attachment 3 is connected to the process connection element 5 via a threaded connection 8, wherein the attachment 3 has an attachment lens 9 on the medium side for coupling the measurement signal into a container 10. In the connected state shown, the attachment lens 9 is designed and arranged such that it shapes the directional characteristic of the measurement signal in the propagation direction of the measurement signal behind the transmission element 6 to adapt it to the process situation, i.e., focuses or widens it.

[0049] In the illustrated embodiment, the add-on lens 9 and the lens 7 are coordinated in such a way that the aperture angle of the measurement signal is reduced by the add-on lens. For this purpose, the aperture of the add-on lens 9 is particularly large. This embodiment is therefore particularly advantageous in measurement situations in which the container 10 is long and narrow, or in which interfering components protrude into the container 10.

[0050] Fig. 2 shows a further embodiment of a system 1 according to the invention, wherein, in contrast to the first embodiment, the lens 7 designed as a transmission element 6 has a larger diameter than the attachment lens 9. According to this embodiment, the lens 7 and the attachment lens 9 are adapted to one another in such a way that the aperture angle of the measurement signal is increased by the attachment lens 9. For this purpose, the diameter of the attachment lens 9 is smaller than the diameter of the lens 7.

[0051] In addition to the deviation in diameter, the attachment lens 9 may also differ in shape, particularly in the radius of curvature and / or in the material of the lens 7. This is Fig. 3 shown.

[0052] Fig. 4 shows a further embodiment, wherein the distance between the attachment lens 9 and the lens 7 designed as a transmission element 6 is shortened.

[0053] Fig. 5shows a further embodiment of a system 1 comprising a level measuring device 2 and an attachment 3, wherein the transmission element 6 is designed as a lens 7 and wherein the attachment lens 9 is matched to the lens 7 in such a way that it both reduces the opening angle of the measuring signal and pivots it by a few degrees.

[0054] In the Fig. 6 In the illustrated embodiment, the diameter of the first lens 7, designed as a transmission element 6, corresponds to the diameter of the attachment lens 9. A dielectric material 12 for guiding the measurement signal is arranged between the lenses 7 and 9. In this exemplary embodiment, both the first lens 7, designed as a transmission element 6, and the attachment lens 9 are designed as a seal, so that the electronics of the control and evaluation unit 4 and the associated cabling (not shown here) are protected by a double seal.

[0055] This embodiment is particularly advantageous in potentially explosive applications.

[0056] Essay 3 of the Fig. 7 The embodiment shown additionally has an overpressure relief device 11, which releases pressure from the attachment 3 in the event of undesired overpressure in the attachment 3, for example if the seal arranged on the process side is defective. This embodiment is particularly advantageous in combination with a double seal with regard to application in potentially explosive measuring situations.

[0057] Fig. 8shows a further embodiment of the system 1 according to the invention, which is arranged on a container 10. In the illustrated embodiment, the attachment 3 is designed as an adapter. The adapter is screwed to both the process connection element 5 and the container connection. Also shown is an overpressure relief device 11, which is arranged on the housing of the attachment 3 outside the container 10. As a result, this embodiment is also particularly suitable for use in potentially explosive atmospheres. Reference symbol

[0058] 1System consisting of level measuring device and attachment 2Level measuring device 3Attachment 4Control and evaluation unit 5Process connection element 6Transmission element 7Lens 8Threaded connection 9Attachment lens 10Vessel 11Overpressure protection 12Dielectric material

Claims

1. Attachment (3) for connection to a fill level measuring device (2) for measuring the fill level of a medium in a container (10), wherein the attachment (3) has an attachment lens (9) which is arranged on the medium side in the mounted state and is suitable for coupling the measuring signal into the container (10), characterized in that the attachment lens (9) is designed and, during operation, can be arranged behind a transmission element (6) of the fill level measuring device (2) in the direction of propagation of the measuring signal in such a way that it changes the opening angle of the measuring signal.

2. System (1) comprising a fill level measuring device (2) for measuring the fill level of a medium in a container (10) and at least one attachment (3) according to claim 1, wherein the fill level measuring device (2) has a control and evaluation unit (4) for generating a measuring signal and a process connection element (5), wherein the process connection element (5) has the transmission element (6) on the medium side, wherein the transmission element (6) is at least partially permeable for the measuring signal, characterized in that at least one attachment (3) is connected to the process connection element (5), so that the attachment lens (9) is arranged behind the transmission element (6) in the direction of propagation in such a way that it changes the opening angle of the measuring signal.

3. System (1) according to claim 2, characterized in that the transmission element (6) is designed as a lens (7) or as a window.

4. System (1) according to one of claims 2 or 3, characterized in that the connection between the process connection element (5) and the attachment (3) is designed as a detachable connection, wherein the connection is designed as a non-positive and / or positive connection, wherein the connection is preferably implemented via a thread or via a latching connection or via a flange connection.

5. System (1) according to one of claims 2 or 3, characterized in that the connection between the process connection element (5) and the attachment (3) is designed as a non-detachable connection, wherein the non-detachable connection is preferably designed as a substance-to-substance connection.

6. System (1) according to any one of claims 2 to 5, characterized in that a holder is provided, wherein the attachment can be connected to the container (10) via the holder.

7. System according to any one of claims 2 to 6, characterized in that the attachment (3) is designed as an adapter, wherein the adapter is designed in particular in such a way that it can be connected both to the process connection element and to a container connection via a thread.

8. System (1) according to any one of claims 2 to 7, characterized in that the at least one attachment (3) has an interior space and that the interior space is at least partially hollow, wherein, in particular, the region between the transmission element (6) and the attachment lens (9) is designed as a hollow space.

9. System (1) according to any one of claims 2 to 8, characterized in that the at least one attachment (3) has an interior space and that at least one dielectric material (12) is present in the interior space of the at least one attachment (3) for guiding and / or for adjusting the measuring signal.

10. System (1) according to any one of claims 2 to 9, characterized in that the at least one attachment (3) has an interior space and that a horn structure for guiding the measuring signal is present in the interior space of the at least one attachment (3).

11. System (1) according to any one of claims 2 to 10, characterized in that the transmission element (6) is designed as a lens (7), wherein the diameter of this lens (7) is smaller than the diameter of the attachment lens (9).

12. System (1) according to any one of claims 1 to 9, characterized in that the transmission element (6) is designed as a lens (7), wherein the diameter of this lens (7) is larger than the diameter of the attachment lens (9).

13. System (1) according to any one of claims 2 to 10, characterized in that the transmission element (6) is designed as a lens (7), wherein the diameter of this lens (7) is substantially identical to the diameter of the attachment lens (9).

14. System (1) according to claim 8, characterized in that an overpressure protection (11) is present in the region of the hollow space for limiting the overpressure in the hollow space.

15. System (1) according to claim 14, characterized in that the overpressure protection (11) is designed in such a way that it is triggered when a limit value for the pressure in the attachment is exceeded, wherein the limit value is smaller than the maximum permitted process pressure, wherein, in particular, the limit value is approximately one third of the process pressure.

16. System (1) according to any one of claims 2 to 15, characterized in that the transmission element (6) and / or the attachment lens (9) are designed as a seal.

17. System according to any one of claims 2 to 16, characterized in that the attachment lens (9) is designed and adjusted to the transmission element (6) in such a way that the attachment lens additionally changes the propagation direction of the measuring signal.

18. System (1) according to any one of claims 2 to 17, characterized in that the fill level measuring device (2) is assigned a plurality of attachments (3) with which different opening angles of the measuring signal and / or different directional changes in the propagation direction of the measuring signal are implemented, wherein, in particular, the individual attachments (3) differ in the shape and / or in the size and / or in the material of the attachment lens (9) and / or in the distance of the attachment lens (9) from the transmission element (6) in the connected state.