MOUNTING ARRANGEMENT WITH A VIBRONIC SENSOR

A mounting arrangement comprises a vibronic sensor and a flange having an opening for transmitting signals through the flange, wherein the vibronic sensor has a vibronic measuring sensor, especially an oscillatable unit, and a measuring transducer, which are arranged on different sides of the flange. The vibronic sensor has a glass feed-through for the signal line between the measuring sensor and the measuring transducer, and the glass feed-through is arranged at least in regions in the opening of the flange.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is related to and claims the priority benefit of German Patent Application No. 10 2021 134 449.2, filed on Dec. 23, 2021, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a mounting arrangement comprising a vibronic sensor.

BACKGROUND

Two typical mounting arrangements of vibronic sensors according to the prior art are shown inFIGS.3and4,FIG.3thereby shows a pressure-tight mounting arrangement100andFIG.4shows a gas-tight mounting arrangement200, respectively with a vibronic sensor101,201.

Given mounting arrangements of the generic type, if used in aggressive process media, for example corrosive process media, this can result in the partial dissolving of the measuring sensor-side sensor elements, and to an intrusion of this process medium into the tubular shaft and the tube volume of the sensor. From there, the process medium can then pass through the tube volume and through the opening of the flange, dissolve the wall of the tubular shaft on the measuring transducer side, and thereby ultimately arrive into the open while bypassing the container wall.

SUMMARY

Starting from the aforementioned prior art, it is an object of the present disclosure to provide a mounting arrangement having greater process safety, especially given use of limit level measurement with corrosive media.

The present disclosure achieves this object via the mounting arrangement and via a use of a mounting arrangement.

A mounting arrangement according to the present disclosure comprises a vibronic sensor and a flange with an opening. Signal lines, e.g., cables from the process side to a measuring transducer, can be guided through the opening.

The vibronic sensor has a vibronic measuring sensor, especially an oscillating fork, and a measuring transducer.

The measuring sensor and the measuring transducer are typically arranged on different sides of the flange.

The vibronic sensor additionally has a glass feed-through for the signal line between the measuring sensor and the measuring transducer. This glass feed-through is arranged at least in regions in the opening of the flange.

Similar to a plug, the glass feed-through closes the flange opening in the event of corrosive damage to the measuring sensor or to the tubular shaft arranged thereon, so that the corrosive process medium must overcome the solid flange in order to arrive into the open. In the meantime, countermeasures can be taken.

This reconfiguration of the previous measurement configuration allows the process safety of the mounting arrangement to be increased without a complete redesign of the existing mounting arrangement being necessary.

Other advantageous embodiments of the present disclosure are the subject matter of the dependent claims.

The vibronic sensor can have at least one tubular shaft which extends into or through the opening of the flange. The glass feed-through is thereby inserted into the tubular shaft or placed onto the tubular shaft.

The glass feed-through can advantageously be connected positively or non-positively to a strain-relief plug coupling, especially via latching elements. This enables quick and uncomplicated mounting of the glass feed-through and at the same time offers a positioning aid.

The mounting arrangement can advantageously be designed to be pressure-tight but not gas-tight, wherein the glass feed-through is inserted into a tubular shaft. Given this variant, the glass feed-through can be protected against a linear displacement at the end on one side by an axial stop, and can be clamped on the other side, especially by a seal, in a tubular shaft.

At one end, the glass feed-through can be integrally joined, especially welded, preferably so as to be flush, along an annular surface with a tubular connector piece of a first adapter component of the tubular shaft to form a structural unit. This variant enables a gas-tight integration of the glass feed-through into a tubular shaft. The structural unit, composed of the glass feed-through together with the tubular connector piece, can define a medium-tight internal tube volume in which a signal line is arranged between the glass feed-through and the measuring transducer.

The flange can have a cylindrical opening into which the structural unit is at least partially inserted.

An adapter component, especially the first adapter component, can additionally have an evacuation opening into which a dowel pin is inserted.

An adapter component can especially be integrally connected to the flange.

The volume of glass in the glass feed-through can preferably extend at least over 15%, especially preferably over 20-50%, of the longitudinal extent of the glass feed-through.

Furthermore according to the present disclosure is a use of a mounting arrangement according to the present disclosure for detecting the limit level of a corrosive medium.

DETAILED DESCRIPTION

Shown inFIG.3is a mounting arrangement100with a vibronic sensor101. An oscillatable unit104in the form of an oscillating fork is depicted. According to the nomenclature of process metrology, this oscillatable unit represents a measuring sensor. Since this variant of the oscillatable unit is used most often, the entire following description relates to an oscillating fork. However, the subject matter of the present disclosure is not limited to the variant of an oscillating fork, but rather encompasses all known types of an oscillatable unit.

The oscillating fork is excited to mechanical vibrations by means of an electromechanical transducer unit105, which is charged with an excitation signal and can be, for example, a piezoelectric stack or bimorph drive. However, it is naturally understood that other embodiments of a vibronic sensor also fall under the present disclosure. Furthermore, an electronic coupling106is shown for connection to an electronics unit, by means of which the signal evaluation and/or feed takes place. This electronic unit is also referred to as a measuring transducer.

InFIG.3, the oscillating fork is developed in the form of a sensor element, which is commonly known as a product of the applicant under the product name LIQUIPHANT. A membrane107and an oscillating element108connected thereto can be seen. The oscillating element has two oscillating rods109on which a paddle110is respectively integrally formed at the end. In operation, the oscillating fork104executes oscillation movements corresponding to the vibration mode with which it is excited. The different oscillation modes are depicted by arrows inFIG.3. The arrows respectively indicate the respective essential directions of movement of the oscillating fork104for the fundamental mode A, as well as for the first B and second C higher oscillation modes. Each of the two oscillating rods109behaves essentially like what is known as a flexural resonator. In the fundamental mode, the two oscillating rods109oscillate in counterphase with respect to one another.

In addition to the vibronic sensor101, the assembly arrangement100also comprises a flange111for connecting to a counter-flange, for example on a tube or a container for forming a flange coupling.

The vibronic sensor101comprises a first tubular shaft114on a measuring sensor side A of the flange111, and a second tubular shaft115on the measuring transducer side B. The tubular shafts114and115are typically used for process decoupling between measuring sensor and measuring transducer, so that the sensitive measuring transducer electronics are not influenced by the process temperature or other process conditions. The tubular shafts114and115can be connected to one another in one piece, and are connected to the flange111via an interface, for example a screw connection or a welded joint. A tube volume117is thereby provided which extends from the first tubular shaft114, through the flange111, into the second tubular shaft115.

A glass feed-through112is arranged in the second tubular shaft115, just below the electronic coupling for the measuring transducer. Glass feed-throughs have long been known in many fields of process metrology. They are used as signal conductors between two cavities, wherein a pressure tightness between the cavities is simultaneously enabled. Given the variant ofFIG.3, the glass feed-through112is only inserted and secured against axial displacement in the second tubular shaft115. This variant is thus designed to be pressure-tight, but not gas-tight.

In the variant ofFIG.4, a second variant of a known mounting arrangement200is shown. The mounting arrangement likewise comprises a vibronic sensor201and a flange211. The vibronic sensor201comprises an oscillatable unit204in the form of an oscillating fork, as well as an electromechanical transducer unit205for generating an excitation signal, an electronic coupling206for connection to an electronics unit, and a tube comprising a first and second tubular shaft214and215for connecting the oscillatable unit204to the electronic coupling206. In this variant as well, the vibronic sensor201has a glass coupling212which is arranged in the tube in a gas-fight manner with a weld seam216.

FIGS.1aand1bshow a mounting arrangement20according to the present disclosure. The mounting arrangement, analogous toFIGS.3and4, thereby has a vibronic sensor1and a flange11. Analogous toFIGS.3and4, the vibronic sensor1has a membrane7as well as oscillating rods9with paddles10. The vibronic sensor1comprises an oscillatable unit4, an electromechanical transducer unit5, an electronic coupling (not shown), as well as a first and second tubular shaft14and15for connecting the oscillatable unit4to the electronic coupling, wherein a tube volume17extends from the first tubular shaft14, through the flange11, into the second tubular shaft15.

The two tubular shafts14and15are thereby inserted into an opening18of the flange11, or placed over an opening of the flange11, and connected, especially welded, to the flange.

The second tubular shaft15is shown as an adapter inFIG.1, but can be extended by a further tubular connector piece or else can be directly connected to a measuring transducer. The tubular shaft15is fixed with the flange11by a circumferential weld seam28.

In the tube volume17, signal lines19run from the electromechanical transducer unit5in the region of the first tubular shaft14, which signal lines can be combined to form a cable assembly for simple handling.

The signal lines19are connected to a glass feed-through12via a plug coupling21for strain relief. The glass feed-through12has electrical line elements in the form of metal pins22which are arranged in a glass matrix.

The metal pins22may be executed as a nickel-iron alloy. Preferably, the metal pins22may additionally be tin-plated.

The glass feed-through12has, in a manner known per se, an outer sleeve made of any material, for example metal or ceramic, and a filling volume of glass which is arranged within the sleeve. The glass is especially an inorganic glass. The filling volume of glass thereby extends preferably at least over 15%, especially preferably over 20-50%, of the longitudinal extent of the outer sleeve.

The glass feed-through12is inserted into an end region of the second tubular shaft15and sealed via an O-ring23. A groove25, into which a locking ring26engages, is provided along the inside of the tubular shaft15. After assembly or insertion of the glass feed-through12into the tubular shaft15, this locking ring26can be inserted into the groove25. The locking ring26then acts as a stop for the glass feed-through12. A clamping of the glass feed-through12in the tubular shaft15can take place via the O-ring23.

A gap27is arranged within the opening18, between the first and second tubular shafts14and15, wherein the glass feed-through12can extend partially into the gap27. The plug coupling21is positioned in the end region of the first tubular shaft14.

The plug coupling21and the glass feed-through12are connected to one another by clamping and/or latching means29. A latching of the two components12and21is thereby especially preferred.

The connection of the two components12and21thereby preferably takes place in the region of the gap27. The metal pins are oriented parallel to the tube axis of the second tubular shaft15and protrude on both sides in segments at least from the fill volume of glass. The connection to the signal lines19shown inFIG.1takes place via the metal pins on one side of the glass feed-through12, and to further signal lines (not shown) on the other side of the glass feed-through12, so that an electrical connection for signal transmission and/or power supply between the transducer unit5and a measuring transducer (not shown inFIG.1) is ensured. The variant ofFIG.3is pressure-tight, but not gas-light. This variant is applied primarily given mounting arrangements20with coated sensors1.

FIGS.2aand2bshow a second mounting arrangement30according to the present disclosure in a gas-tight embodiment. Components which are structurally identical toFIGS.1aand1bare provided with identical reference signs.

The components of the vibronic sensor1on the measuring sensor side A are identical toFIGS.1aand1b.However, in order to achieve a gas-tight embodiment, the glass feed-through42has a stepped design and can rest with stops37along end faces of the first tubular shaft14.

Like the tubular shaft15ofFIGS.1aand1b,the second tubular shaft40serves to connect to the measuring transducer. It is constructed in several parts inFIGS.2aand2b. It has a first adapter component32, a second adapter component31with an evacuation opening34, and a third adapter component36. The three adapter components are welded to one another in a gas-tight manner by weld seams35,39.

The evacuation opening is sealed in an airtight manner by a dowel pin33and an additional optional weld. The first adapter component32has a tubular connector piece38which projects into the lumen of the second adapter component31and is joined, especially welded, at the end to the glass feed-through42. Accordingly, the combination of adapter component32with the tubular shaft38and with the glass feed-through42has an inner tube volume41. This inner tube volume41can also be evacuated.

Analogous to the variants ofFIGS.1aand1b,the glass feed-through42has metal pins22which protrude on both sides from the glass feed-through42. The lumen between the tubular connector piece38and the second adapter component31is additionally evacuated by suction through the evacuation opening34. The tubular shaft40can be connected to the flange11via a weld seam28, analogous toFIGS.1aand1b.The double-walled structure of the tubular shaft40enables a gas-tight embodiment of the second tubular shaft40and of the mounting arrangement30overall.

InFIG.2b,the protruding ends of the metal pins22are connected to a cable assembly of the signal lines19. The variant illustrated inFIGS.2aand2bwelds and forms the glass feed-through in a gas-tight manner.

This embodiment/glass feed-through can also be used, inter alia, in high-temperature applications.

The special feature of the variants according to the present disclosure ofFIGS.1aand1b,and2aand2b, is that the glass feed-through12,42is at least in regions on a with the flange11,41.

If a comprehensive decomposition of individual sensor elements of the measuring sensor side A occurs, for example due to an aggressive process medium, this process medium cannot escape via the flange opening18and by decomposition of the wall of the second tubular shaft15,40. Rather, the flange11serves as a cover in such an event, and the glass feed-through12,42acts like a glass stopper in the flange11, which prevents the process medium from escaping over a certain period of time.