WO2009000679A1

WO2009000679A1 - Magnetoinductive flowmeter

Info

Publication number: WO2009000679A1
Application number: PCT/EP2008/057487
Authority: WO
Inventors: Frank Voigt
Original assignee: Endress+Hauser Flowtec Ag
Priority date: 2007-06-26
Filing date: 2008-06-13
Publication date: 2008-12-31
Also published as: DE102007029563A1; DE102007029563B4

Abstract

The invention describes a cost-effective compact magnetoinductive flowmeter having a measuring tube (1), through the interior of which the medium flows during measurement operation, a magnetoinductive flow measuring sensor which is arranged on the measuring tube (1) and comprises an apparatus, which is mounted on the measuring tube (1) and is intended to generate a magnetic field which permeates the measuring tube (1), and electrodes (3) which are inserted into the measuring tube (1) and can be used to tap off a voltage which is induced in the medium during measurement operation, and a single meter housing (7) in which the measuring sensor and meter electronics (9) are arranged and which comprises two half-shells (11, 13) which are connected to one another, surround the measuring tube (1), have an electronics space (23) which is arranged outside the measuring tube (1) and in which the meter electronics (9) are arranged, and have a connection space (25) which is arranged outside the measuring tube (1), opens into the electronics space (23) and in which connection lines (27) which are connected to the meter electronics (9) run, which connection lines are routed to the outside via a bushing (31) which is inserted into an outer wall (29) of one of the two half-shells (13).

Description

description

Magnetic inductive flowmeter

The invention relates to a magnetic inductive flowmeter.

Flow meters are used in industrial metrology for the measurement of volume flows.

A current measurement method is based on the magneto-hydrodynamic principle and is used in magnetic inductive flowmeters. In this case, an at least to a small extent electrically conductive medium whose volume flow is to be measured, passed through a measuring tube which is penetrated substantially perpendicular to the tube axis of a magnetic field. Perpendicular to the magnetic field moving charge carriers induce perpendicular to their flow direction, a voltage which can be tapped via appropriately arranged measuring electrodes. For this purpose, the measuring electrodes are either capacitively or galvanically coupled to the medium. The induced voltage is proportional to averaged over a cross section of the measuring tube flow velocity of the medium and thus proportional to the volume flow.

Commercially available magneto-inductive flowmeters have regularly a measuring tube, the interior of which flows through the medium in the measuring operation. Arranged on the measuring tube is a magnetically inductive flow measuring transducer which comprises a device for generating a magnetic field passing through the measuring tube and measuring electrodes inserted in the measuring tube. In the measuring mode, a voltage induced in the medium can be tapped off via the electrodes. The sensor is usually surrounded by a sensor housing, which consists for example of two interconnected the measuring tube enclosing half-shells. On the sensor housing, a separate electronics housing is mounted, in which a meter electronics is located, which is connected for example via a corresponding connection or passage electrically to the arranged in the sensor housing sensor. The meter electronics preferably includes the entire for the Operation of the flowmeter required electronics. These include electronics for controlling the device for generating the magnetic field, an electronics for recording measured by the measuring electrodes measuring signals, an electronics for processing and / or processing of these measurement signals, as well as a signal processing that generates all the desired measurement results based on the measurement signals and another Display and / or processing. In addition, the power supply of the sensor via the meter electronics.

The electronics housing generally has a connection space in which run to the meter electronics connected connection lines, which are guided via an inserted into an outer wall of the electronics housing implementation to the outside. These power cables, which are accessible from the outside, are used to supply power to the measuring device, if necessary to communicate with the measuring device, and to transmit the measurement results.

An example of such a flow meter is sold under the product name Promag 5OW by the applicant flow meter.

Such flowmeters are relatively expensive to manufacture, since both the sensor housing and the electronics housing must be made, the two housings must be mechanically connected to each other, and an electrical connection between the sensor and the meter electronics must be provided.

It is an object of the invention to provide a cost-effective compact magnetic inductive flowmeter. For this purpose, the invention consists in a magneto-inductive flowmeter for measuring a flow of a medium through an existing pipeline system, with

a measuring tube, the interior of which flows through the medium during measuring operation,

- One arranged on the measuring tube magnetically inductive Flow sensor, which is a mounted on the measuring tube device for

Generation of a measuring tube passing through the magnetic field, and in the measuring tube inserted electrodes over which a voltage induced in the medium can be tapped in the measuring operation comprises, and

A single meter housing,

- in which the sensor and a meter electronics are arranged,

Consisting of two interconnected half shells surrounding the measuring tube,

- In which an outside of the measuring tube arranged electronics space is provided, in which the meter electronics is arranged,

- In which a arranged outside of the measuring tube opening into the electronics compartment connection space is provided in the connected to the meter electronics connection lines run, which are guided over an inserted into an outer wall of one of the two half shells passage to the outside.

According to one embodiment, the electronics compartment is arranged in a first half-shell and the connection space is arranged in a second half-shell.

According to one embodiment, the meter housing is completed by a the electronics room and the terminal compartment to the outside final lid, in which an externally accessible user interface of the flowmeter and / or a display is integrated.

According to one embodiment, the meter electronics is arranged on a circuit board having two opposing edge portions extending in two opposite identical form in one of the half shells integrated guide rails.

According to a preferred embodiment, the sensor comprises a field jacket sheet, which surrounds the measuring tube, and the guide rails and the board are arranged parallel to an outer space facing the electronics compartment of the field jacket plate.

According to a preferred embodiment, a plug contact is provided on an end face of the board, via which the meter electronics can be connected to the sensor, and in the first half-shell an interface print is provided with a receiving socket to which the sensor is connected, and in the the plug contact can be inserted.

According to one embodiment, the lid is detachable with the

Encoder housing is connected, and the meter electronics is interchangeable through an opening formed by the removal of the lid of the meter housing.

According to a development, the half-shell outside in the area of

Carrying out a recess in which an outwardly facing part of the implementation is protected from external mechanical influences.

According to one embodiment, the two half-shells made of a thermoplastic material and are connected to each other non-positively or cohesively.

The magnetic inductive flowmeter according to the invention has the advantage that it has only a single meter housing. This makes it very compact, has small dimensions, and can be produced inexpensively.

Another advantage is that this meter offers a high degree of functionality. The integration of the user interface and / or the display in the lid provides additional convenience for the user, without thereby increasing the dimensions of the meter as a whole. In addition, the meter electronics can be easily replaced by removing the lid.

The invention and further advantages will now be explained in more detail with reference to the figures of the drawing, in which an embodiment is shown; like parts are provided in the figures with the same reference numerals. Fig. 1 shows a partially sectioned view of a magnetic inductive flowmeter according to the invention;

Fig. 2 shows a section through the flow meter of Fig. 1;

Fig. 3 shows: a view of a first half-shell of the meter housing of Fig. 1;

FIG. 4 shows a view of a second half-shell of the meter housing of FIG. 1; FIG. and

Fig. 5 shows: a view of a lid of the meter housing with an integrated therein user interface and a display integrated therein.

Fig. 1 shows a partially sectioned view of a magnetic inductive flowmeter according to the invention for measuring a flow of a medium through an existing pipeline system. For this purpose, the flowmeter on a measuring tube 1, the interior of which flows through the medium in the measuring operation. At the end of the measuring tube 1 are process connections 2, in the exemplary embodiment shown in FIG. 1 two flanges are formed, with which the measuring tube 1 of the flowmeter can be inserted into the existing pipeline system.

The flowmeter has a magnetically inductive flow measuring transducer arranged directly on the measuring tube 1. This device comprises a device mounted on the measuring tube 1 for generating a magnetic field passing through the measuring tube 1, and electrodes 3 inserted into the measuring tube 1, by means of which a voltage induced in the medium can be tapped in the measuring mode.

Fig. 2 shows a section through the flow meter of Fig. 1; in which the device for generating the magnetic field and the electrodes 3 are shown. The device for generating the magnetic field comprises a coil arrangement, which in the illustrated embodiment consists of two coils 5 arranged opposite one another on both sides of the measuring tube 1. In order to generate the magnetic field, the coils 5 are flowed through in measuring operation by an excitation current, which causes the formation of a magnetic field, the measuring tube 1 in essentially traversed perpendicular to the tube axis. The device additionally comprises a field jacket plate 4, which surrounds at least a part of the measuring tube 1. In the illustrated embodiment, the field coat plate 4 has an octagonal cross-section, and serves to return the magnetic field.

Perpendicular to the magnetic field moving charge carriers induce perpendicular to the flow direction, a voltage which can be tapped off via the electrodes 3. For this purpose, two electrodes 3 are provided in the illustrated embodiment, which are arranged opposite each other on both sides of the measuring tube 1 such that an imaginary line connecting the electrodes 3 perpendicular to an imaginary line connecting the two coils 5 and thus perpendicular to the magnetic field.

The flowmeter according to the invention has a single

Measuring device housing 7, in which the measuring tube 1 is guided and in which both the entire sensor and the entire meter electronics 9 of the flowmeter are arranged.

The meter housing 7 consists of two interconnected the measuring tube 1 enclosing half-shells 11 and 13. Preferably, a meter housing 7 final lid 15 is also provided. Fig. 3 shows a view of the first half-shell 11, Fig. 4 is a view of the second half-shell 13 and Fig. 5 is a view of the lid 15. The two half-shells 11, 13 each have two opposite outer walls, in each of which a semicircular recess 17, between which the measuring tube 1 is clamped. Between the voltage applied to the measuring tube 1 end faces 19 of the recesses and the measuring tube 1 is one, not shown in the figures, sealing provided. In the end faces 19 extends for this purpose a groove 21, for receiving the seal. As a seal is suitable, for. a to be inserted into the groove 21 O-ring or a molded seal.

The two half-shells 11, 13 are preferably made of a thermoplastic material and are connected to each other non-positively or cohesively. Preferably, thermoplastics are used for example, by glass fibers reinforced polyamide (PA), polyurethanes or polycarbonates used. A non-positive connection, for example, by a screw connection of the two half-shells 11, 13 are effected together. A cohesive connection can be effected for example by a weld or a bond.

Alternatively, the half shells 11, 13 may be made of die-cast aluminum. In that case, however, at least partial areas of the half-shells 11, 13 would have to be provided with an insulating inner coating.

In the half-shells 11, 13 a arranged outside the measuring tube 1 electronics compartment 23 is provided, in which the meter electronics 9 is arranged. In the illustrated embodiment, the electronics compartment 23 is located in the first half-shell 11. Alternatively, it could also be arranged in the second half-shell 13 or extend from the first into the second half-shell.

The meter electronics 9 includes here all the electronics required for the operation of the flowmeter. These include electronics for controlling the device for generating the magnetic field, an electronics for recording measured by means of the electrodes 3 measuring signals, an electronics for processing and / or processing of these measurement signals, as well as a signal processing that generates all the desired measurement results from the measurement signals and a makes available to further display and / or processing. In addition, the power supply of the flowmeter via the meter electronics 9.

In the half-shells 11, 13 a further arranged outside the measuring tube 1, opening into the electronics compartment 23 terminal space 25 is provided in which connected to the meter electronics 9 connecting lines 27 extend over a inserted into an outer wall 29 of the half shells 13 Passage 31 are led to the outside. In the illustrated embodiment, the Terminal space 25 arranged in the second half-shell 13, and the passage 31 is inserted into the second half-shell 13. Alternatively, the connection space 25 could also be arranged in the first half-shell 11 or extend from the first into the second half-shell.

The outgoing leads 27 serve the

Power supply to the flowmeter, the transmission of measurement signals and / or measurement results and, if appropriate, communication with the flowmeter.

Preferably, the second half-shell 13 outside in the region of the passage 31 on a recess 32 in which an outwardly facing part of the bushing 31 is arranged protected from external mechanical influences. This indentation 32 is closed on the outside by a wall piece 34 of the second half-shell 13, the outer contour of which follows the outer contour of the meter housing 7.

Electronics room 23 and terminal compartment 25 form an interior which is closed to the outside of the lid 15. The lid 15 is detachably connected to the two half-shells 11, 13. In the illustrated embodiment, the lid 15 has a rectangular base, which covers the interior. In each of the four corners of the lid 15, a bore 33 is provided, are used in the screws, with which the lid 15 is screwed onto the two half-shells 11, 13. On the lid 15 facing end surfaces of the two half-shells 11, 13 corresponding threaded bores 35 are provided for receiving the screws.

In the lid 15 an externally accessible user interface 37 of the flowmeter and / or a display 39 is integrated. In the exemplary embodiment shown, the user interface 37 comprises a membrane keyboard with buttons 41 which can be operated from the outside. Optionally, optical buttons can also be used in conjunction with a transparent cover. The display 39 is for example a commercially available display. User interface 37 and display 39 are inside the

Meter housing 7 connected to the meter electronics 9. The integration of these elements in the already existing cover 15 has the advantage that this space is saved. This makes the flowmeter even more compact, making it convenient to use in applications where space is at a premium.

The meter electronics 9 is preferably arranged on a circuit board 43. As a result, a small height is effected, which allows to arrange the meter electronics 9 in an electronics compartment 23 with a very low height. The board 43 has a rectangular base. The assembly of the board 43 is carried out by the board 43 is inserted into integrated into the outer walls of the first half-shell 11 guide rails 45. In the assembled state, the two edge areas of the board 43 arranged opposite one another on the two longitudinal sides of the board 43 run in the two mutually opposite identical guide rails 45.

Preferably, the guide rails 45 and thus the circuit board 43 are arranged parallel to a the electronics space 23 facing lateral surface 47 of the octagonal in cross-section field jacket plate 4.

On one end side of the board 43, a plug contact 49 is provided, via which the meter electronics 9 can be connected to the sensor. As a counterpart to this plug-in contact 49 is in a rear wall of the first half-shell 11 a, in Fig. 3 shown, interface print is provided with a receiving socket 51, in which the plug contact 49 is inserted, and to which the sensor is connected. The electrical connection of the meter electronics 9 to the sensor then takes place automatically when installing the board 43, and is guided by the guide rails 45.

The flow meter according to the invention has the advantage that the lid 15 is releasably connected to the half-shells 11, 13. Corresponding is

The meter electronics 9 by a by removing the lid 15th resulting opening of the meter housing 7 through exchangeable. As a result, despite the compactness of the flowmeter a high degree of flexibility, esp. Given a possible maintenance or repair of the meter is given.

Table 1 Measuring tube Process connection Electrode Sheath plate Kitchen sink

meter case

Meter electronics first half shell second half shell

Cover semicircular recess

face

groove

electronics compartment

connection space

connecting cables

outer wall

execution

indentation

drilling

wall piece

threaded hole

user interface

display

button

circuit board

guide rail

Lateral surface of the field jacket sheet

plug contact

Interface print with recording socket

Claims

claims

1. 1. Magnetic inductive flowmeter for

Measuring a flow of a medium through an existing pipeline system, with

a measuring tube (1), the interior of which flows through the medium during measuring operation,

a magnetically inductive flow measuring transducer arranged on the measuring tube (1), comprising a device mounted on the measuring tube (1) for generating a magnetic field passing through the measuring tube (1), and electrodes (3) inserted in the measuring tube (1) in the medium induced voltage can be tapped, and,

a single meter housing (7),

- in which the sensor and a measuring device electronics (9) are arranged,

- consists of two interconnected the measuring tube (1) enclosing half-shells (11, 13),

- In which an outside of the measuring tube (1) arranged electronics space (23) is provided, in which the meter electronics (9) is arranged,

- in which one outside the

Measuring tube (1) arranged in the electronics compartment (23) emptying terminal space (25) is provided in the connected to the meter electronics (9) connecting lines (27) extending over an in an outer wall (29) of one of the two half shells (13) inserted passage (31) are led to the outside.

2. 2. Electromagnetic flowmeter according to claim 1, wherein the electronics compartment (23) in a first half-shell (11) is arranged, and the connection space (25) in a second half-shell (13) is arranged.

3. 3. Magnetic inductive flowmeter according to claim 1 or 2, wherein the meter housing (7) of a the electronics compartment (23) and the terminal compartment (25) to the outside final lid (15) is completed, in which an externally accessible control surface (37) of the flowmeter and / or a display (39) is integrated.

4. 4. Magnetic inductive flowmeter according to claim 1, wherein the meter electronics (9) on a circuit board (43) is arranged, which has two mutually opposite edge regions, in two opposite identical form in one of the half-shells (11) integrated guide rails ( 45).

5. 5. Magnetic inductive flowmeter according to claim 4, wherein

- The sensor a field coat plate

(4), which surrounds the measuring tube (1), and

- The guide rails (45) and the circuit board (43) parallel to a the electronics space (23) facing lateral surface (47) of the field jacket plate (4) are arranged.

6. 6. Magnetic inductive flowmeter according to claim 4, wherein

a plug contact (49) is provided on one end side of the board (43), via which the meter electronics (9) can be connected to the sensor,

in the first half-shell (11) an interface print with a receiving bush (51) is provided,

- to which the sensor is connected, and

- In which the plug contact (49) can be inserted.

7. 7. Magnetic inductive flowmeter according to claim 3, wherein the lid (15) releasably connected to the half-shells (11, 13), and the meter electronics (9) by a by removing the cover (15) resulting opening of the meter housing (7) is interchangeable.

8. 8. Electromagnetic flowmeter according to claim 1, wherein the half-shell (13) outside in the region of the passage (31) has a recess (32) in which an outwardly facing part of the passage (31) protected from external mechanical influences is arranged.

9. 9. Magnetic inductive flowmeter according to claim 1, wherein the two half-shells (11, 13) consist of a thermoplastic material and are positively non-positively or materially connected.