DE102017127993A1 - field device - Google Patents

Abstract

The invention relates to a field device (1) which is hygienically resistant to a round terminal (20, 20 ') can be fastened. For this purpose, it comprises a connection region (10) which corresponds to the round connection (20, 20 '), a sealing disk (12) which can be arranged between the connection region (10) and the round connection (20, 20'), and a process separation (10) which can be attached in the connection region (10). 11) which is designed to seal the field device (1) in the fastened state to the round terminal (20, 20 '). According to the invention, the process separation (11) has an edge region (110) overlapping in relation to the inner diameter (D) of the sealing disc (12) in such a way that the process separation (11) between the connection region (10) and the sealing disc (12) is fixed , On the other hand, the sealing disc (12) and the connection area (10) form a mutual end stop (13). Hygienically critical gaps in the interior of the round connection (20, 20 ') are avoided by the overlap. In addition, a squeezing of the process separation (11) is avoided during assembly of the field device (1), so that the tightness is maintained even with repeated installation of the field device (1).

Description

The invention relates to a field device, which is hygienically resistant fastened to a round terminal.

In process automation technology, field devices are often used to detect process variables. For this purpose, sensors are used which are used, for example, in level gauges, flowmeters, pressure and temperature measuring devices, pH redox potential measuring devices, conductivity meters, or comparable measuring devices. They record the corresponding process variables, such as level, flow, pressure, temperature, pH, redox potential or conductivity. Various types of field device types are manufactured and distributed by Endress + Hauser.

The container in which the fill level or any other medium property of the filling material is to be measured has, as a rule, a round connection, for example a flange connection or a clamping connection, for mounting the respective field device. In addition, screw caps or welds are used. In this case, to protect the field device interior from the contents at the round connection between the container and the field device, a process separation from a corresponding filling material-resistant plastic is introduced. A level gauge with such a process separation, for example, in the publication WO 002015082146 A1 shown. Thereafter, the process separation is attached to the round connection between the field device and the container so that the process separation is fixed during assembly by appropriate clamping on the round terminal. The edge area of the process separation required for clamping, which overlaps the inner diameter of the round terminal, offers the advantage of a gap-poor sealing of the field device to the interior of the round terminal. As a result, the field device can potentially be used for applications with certain hygiene requirements. Corresponding requirements for the use of field devices in hygienic areas are formulated, for example, in the Position Paper, Version 3, December 2015 of the "European Hygienic Engineering & Design Group (EHEDG)".

However, a problem with the abovementioned design of the field device or the process separation is that excessive tightening of the flange or round connection can damage the process separation in the overlapping edge area due to excessive compression. At least with repeated (dis) assembly of the field device, this can lead to such an inelastic change in shape of the edge region, so that the tightness or the hygiene conformity are lost.

The invention is therefore based on the object to provide a field device that hygienic resistant can be attached to a round terminal.

• - Einen zum Rundanschluss korrespondierenden Anschlussbereich,
• - eine zwischen dem Anschlussbereich und dem Rundanschluss anordenbare Dichtscheibe, die einen vordefinierten Innendurchmesser aufweist,
• - eine im Anschlussbereich anbringbare Prozesstrennung, die ausgelegt ist, um das Feldgerät im befestigten Zustand zum Rundanschluss hin abzudichten, wobei die Prozesstrennung einen in Bezug zum Innendurchmesser der Dichtscheibe derart überlappenden Randbereich aufweist, dass im befestigten Zustand
  • ◯ die Prozesstrennung zwischen dem Anschlussbereich und der Dichtscheibe fixiert ist, und
  • ◯ die Dichtscheibe und der Anschlussbereich einen gegenseitigen, insbesondere metallischen Endanschlag bilden.

This problem is solved by a field device that can be attached to a round connector. It includes:

• A terminal area corresponding to the round terminal,
• a sealing disk which can be arranged between the connection region and the round connection and which has a predefined inner diameter,
• - An attachable in the connection area process separation, which is designed to seal the field device in the attached state to the round terminal, the process separation has a relation to the inner diameter of the sealing disc such overlapping edge region that in the attached state
  • ◯ the process separation between the connection area and the sealing disk is fixed, and
  • ◯ the sealing washer and the connection area form a mutual, in particular metallic, end stop.

This inventive attachment of the field device to a round terminal has the advantage that any gaps in the interior of the round terminal are avoided by the overlap. As a result, the field device is potentially used for hygienic applications. Due to the configuration of the sealing disk and the connection area as a mutual end stop, a compression of the process separation in the overlapping edge area during assembly of the field device is also avoided or defined. An overuse of the process separation in the edge area is thus excluded during assembly, so that the tightness and the hygienic compatibility at the round connection remain even with repeated installation of the field device.

For use in hygienically critical applications, it is advantageous if the connection area and the sealing disk are designed so that the level gauge is attached to a terminal connection, in particular according to the Standard ISO 2852 or the Standard DIN 32676 , is attachable. Above all, in order to meet the connection sizes mentioned in these standards, it is advantageous if the connection area and the sealing disc are designed in this way are that the level gauge can be attached to a round terminal with an inner diameter between 20 mm and 300 mm. Equally conceivable would be the implementation of the idea according to the invention also at a flange connection or a screw connection, for example according to the Standard DIN 11851 (known as "milk tube fitting").

The mounting of the field device according to the invention on the container can be facilitated if a corresponding centering means, in particular a centering ring, is provided for centering the level measuring device in relation to the round terminal. At clamp connections after the Standard ISO 2852 corresponding sealing rings are designed accordingly with a centering ring. At the terminal connection itself, or at the connection area corresponding recesses are provided in this case.

To reduce gaps and associated, increased hygiene compatibility, a further advantageous embodiment is that the sealing disc is made in an overlap region for process separation of an elastic material. In this case, the thickness of the elastic material in the overlapping region can be dimensioned, for example, with a defined excess, in order to reinforce or optimize the clamping of the process separation between the sealing disk and the connection region in the fastened state of the field device. In connection with a reduction of gaps, it is also advantageous if the sealing disc is dimensioned so that the inner diameter of the sealing disc in the attached state is as large as possible, in particular the same size as the inner diameter of the round terminal. In the other case, there would be the danger of hygienically critical deposits in the resulting joint.

If the field device is a radar-based or ultrasound-based fill level measuring device, the invention can bring about a synergistic advantage in that the process separation can be designed as a quasi-optical lens for bundling electromagnetic transmit and receive signals of the fill level measuring device. Alternatively, the attachment according to the invention can of course also be used for any other field device, such as, for example, capacitive level measuring devices whose process separation comprises a waveguide or rod probe for immersion in the filling material.

• 1: Ein Füllstandsmessgerät an einem Rundanschluss eines Behälters, und
• 2: eine vergrößerte Darstellung im Bereich des Rundanschlusses.

Based on the following figures, the invention will be explained in more detail. It shows:

• 1 : A level gauge on a round terminal of a container, and
• 2 : an enlarged view in the area of the round connection.

For a general understanding of the attachment of field devices according to the invention is in 1 a basic arrangement of an ultrasonic or radar-based level gauge 1 on a container 2 shown. In the container 2 there is a filling material 3 , its level by the level gauge 1 is to be determined. Depending on the purpose, inside the container 2 a temperature of about 100 ° C and / or an overpressure of several bar prevail, for example, due to sterilization, the contents 3 currently going through. In addition, the level gauge can 1 They are also used in vacuum or vacuum applications.

For measuring the level, the level gauge is 1 in a known installation height above the contents 3 so on the container 2 arranged that there are radar or ultrasound-based transmission signals S _HF in the direction of the surface of the filling 3 sending out. After reflection on the product surface, the level gauge receives 1 the reflected received signals E _HF after appropriate term. Based on the determined running time, the distance to the product surface and, in turn, the fill level are determined. Of course, the invention is also in the case of other types of field devices as well as at other installation locations, as the top of the container 2 , executable.

For fastening the level gauge 1 points the container 2 a round connection 20 ' (in 1 realized as flange connection). For this purpose, the level gauge 1 with a corresponding connection area 10 designed. An enlarged view of this area is in 2 shown. It can be seen that to a pressure and temperature-resistant sealing of the level gauge 1 opposite the interior of the container 2 in the area of the round connection 20 ' a suitably designed process separation 11 , (standard made of a chemically inert plastic such as PP, PE, PEEK or PTFE) is arranged. For bundling the electromagnetic transmission and reception signals S _HF . E _HF of the level gauge 1 is the process separation 11 in the middle area also as quasi-optical lens 111 designed. It goes without saying that the optical lens 111 is only optional and should be omitted accordingly in implementing the invention in a field device other than a level gauge.

At the in 2 shown round connection 20 it is a terminal connection 20 according to the standards ISO 2852 (also known under the term "Tri-Clamp") or DIN 32676. Therefore, in the connection area 10 additionally a sealing washer 12 with a centering ring 120 placed. The connection area 10 of the level gauge 1 and the terminal connection 20 cover accordingly corresponding recesses for the centering ring 120 , According to the Standards ISO 2852 or DIN 32676 can the inner diameter of the terminal connection 20 between 20 mm to over 300 mm.

How out 2 or the enlarged section X shows, is the connection area 10 of the level gauge 1 to start the process separation 11 designed with a corresponding recess. In this case, the recess of the connection area 10 or the process separation 11 According to the invention designed so that the process separation 11 one in relation to the inside diameter D _D the sealing disc 12 overlapping border area 110 having. This will process separation 11 in the attached state between the connection area 10 and an overlap area 14 the sealing disc 12 fixed. In the embodiment shown, the recess has the connection area 10 for the process separation 1 a thickness of 2.6 mm; The process separation 11 therefore, for the purpose of being clampable in the fastened state, at least in the overlapping edge area 110 a thickness of 2.6 mm plus a possible, compressible oversize on. The possible excess is the elasticity of the material used in the process separation 11 interpreted.

Especially to achieve a sufficient overpressure or negative pressure resistance is the edge area 110 or the overlap region with a sufficient diameter difference (in the embodiment shown, at least 0.5 mm) to be measured.

Furthermore, the connection area 10 and the process separation 11 According to the invention designed so that the sealing disc 12 and the connection area 10 a mutual, metallic end stop 13 form. That means the connection area 10 and the sealing disc at least in the region of the end stop 13 made of stainless steel, for example. In the embodiment shown results in the end stop 13 through the circumferential contour of the connection area 10 or the sealing washer 12 outside and inside the centering ring 120 , For the purposes of the invention, it would of course also conceivable, the end stop 13 in other ways (for example, exclusively by the circumferential contour outside the centering ring; in addition, it is not stipulated that the contour must be circumferential, that is, without interruption).

According to the Standards ISO 2852 and DIN 32676 corresponds to the inner diameter D _D the sealing disc 12 in the embodiment shown, the inner diameter D _R of the terminal connection 20 , Thus, the requirement is met that the inner diameter D _D the sealing disc 12 to avoid gaps at least not larger than the inner diameter D _R of the terminal connection 20 may be. In addition, the gasket is 12 , as from the magnification view X from 2 appears in the overlap area 14 for process separation 11 made of an elastic material, such as an elastomer. Thus, the inside of the container 2 in the area of the terminal connection 20 , in particular between the process separation 11 and the sealing washer 12 , gap-free sealed. Overall, the inventive attachment of the level gauge is suitable 1 due to the gap-free and dimensionally stable design so preferably for applications with high hygienic requirements.

LIST OF REFERENCE NUMBERS

1

field device

2

container

3

filling

10

terminal area

11

process separation

12

sealing washer

13

end stop

14

overlap

20

terminal connection

20 '

flange

110

border area

111

Quasi-optical lens

120

centering

D _D

Inner diameter of the sealing washer

D _R

Inner diameter of the round connector

E _HF

receive signals

S _HF

transmission signals

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 00/2015082146 A1 [0003]

Cited non-patent literature

• Standard ISO 2852 [0008, 0009]
• Standard DIN 32676 [0008]
• Standard DIN 11851 [0008]
• Standards ISO 2852 [0016, 0020]
• DIN 32676 [0016, 0020]

Claims (9)

Field device which can be fastened to a round terminal (20, 20 '), comprising: - a terminal area (10) corresponding to the round terminal (20, 20'), - one between the terminal area (10) and the round terminal (20, 20 ') Anordenbare sealing washer (12) having a predefined inner diameter (D _D ), - in the connection region (10) attachable process separation (11) which is designed to the field device (1) in the attached state to the round terminal (20, 20 ') to seal off, wherein the process separation (11) in relation to the inner diameter (D _D ) of the sealing disc (12) such overlapping edge region (110), that in the attached state ◯ the process separation (11) between the connection region (10) and the sealing disc (12) is fixed, and ◯ the sealing disc (12) and the connection area (10) form a mutual end stop (13). Field device after Claim 1 , wherein the connection area (10) and the sealing disc (12) are designed so that the level measuring device (1) to a round terminal (20, 20 ') with an inner diameter (D _R ) between 20 mm and 300 mm can be fastened. Field device after Claim 1 or 2 , wherein the connection area (10) and the sealing disc (12) are designed so that the level gauge (1) on a terminal connection (20), in particular according to the standard ISO 2852 or the standard DIN 32676, can be fastened. Field device according to at least one of Claims 1 to 3 , wherein a centering means (120), in particular a centering ring, for centering the level measuring device (1) in relation to the round terminal (20, 20 ') is provided. Field device according to at least one of the preceding claims, wherein the sealing disc (12) in an overlap region (14) for process separation (11) is made of an elastic material. Field device according to at least one of the preceding claims, wherein the sealing disc (12) is dimensioned such that the inner diameter (D _D ) of the sealing disc (12) in the attached state is at most as large, in particular the same size as the inner diameter (D _R ) of the round terminal (20, 20 '). Field device according to at least one of Claims 1 to 6 , which is a radar-based, ultrasound-based, or capacitive level gauge (1). Field device after Claim 7 , wherein the process separation (11) comprises a quasi-optical lens (111) for the bundling of electromagnetic transmission and reception signals (S _HF , E _HF ) of the level measuring device (1). Field device after Claim 7 , wherein the process separation (11) comprises a particular sheathed rod for guiding electromagnetic transmitting and receiving signals (S _HF , E _HF ) of the level measuring device (1) or for detecting its capacity.

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