DE102009045768A1 - Device for determining and/or monitoring predetermined filling level of bulk goods in silo, has one module detachably connected with another module, where former module includes current-meter and latter module includes motor and motor shaft - Google Patents

Abstract

The device has a module (7) detachably connected with another module (8). The former module includes a process connector (5), a current-meter (1) and a current-meter shaft (4), and the latter module includes a motor (2) and a motor shaft (3). The motor is used for driving the current-meter, where the current-meter is connected to the motor. The motor shaft and the current-meter shaft are detachably interconnected via a coupling (6). A fixed connection is produced between the modules. The coupling is designed as a spring coupling or a spring disk coupling.

Description

The present invention relates to a device for determining and / or monitoring a predetermined filling level of a bulk material in a container with a measuring blade, which performs at least one rotational movement in the container, a motor for driving the measuring blade and a shaft, via which the measuring blade connected to the motor wherein the shaft is divided into a driving motor shaft and a driven metering shaft and wherein the motor shaft and the metering shaft are releasably connected to each other via a coupling.

In particular, the device is suitable for monitoring a minimum or maximum level of a medium in the container; In this case, the device is referred to as a rotary vane limit switch. The rotary vane limit switch is hereby mounted on the height to be monitored in the container.

Containers and silos for the storage of bulk materials are widely used. In order to monitor the fill level of the bulk material, so-called rotary vane limit switches are frequently used. These consist essentially of a measuring wing, a shaft and a motor, wherein the motor via the shaft placed in the container mounted on the monitored level height measuring wings in a rotary motion. If, for example, when filling the container, the bulk goods hit the rotating measuring blade, the measuring blade is inhibited or even stopped by the resistance of the bulk material in its rotary motion. The motor is rotatably mounted and thereby moves from a rest position to a switching position. As a result, two contacts are switched, wherein the first contact signals the reaching of the level, for example by forwarding a signal to a control room. The second contact causes the motor to shut down. As soon as the bulk material releases the measuring wing again, the motor rotates back to its rest position and sets the measuring wing back in a rotary motion.

The measuring blade is directly exposed to the bulk material and can therefore be subject to high mechanical loads. In particular, filling the container with heavy, coarse bulk materials can cause the measuring blade to be exposed to suddenly occurring large forces. This can lead to an overload of the engine by the coupling with the engine, whereby this damage can take. If the motor needs to be replaced or repaired, removal of the entire meter is required. For this purpose, an emptying of the container is at least until below the position of the measuring device necessary, since at this point a hole in the container wall remains. This makes the repair of engine damage very expensive and expensive.

In the prior art, the problem of engine damage due to overloading is counteracted by the fact that the measuring blade is driven via a slip clutch. In Scripture US 4,147,906 this is a spring-loaded coupling and in the Scriptures EP 1357366 B1 proposed a magnetic slip clutch.

If the engine still fails, for example, due to aging or due to excessive temperatures, a costly replacement is still required.

The object of the invention is to provide a device for monitoring a predetermined level, which is easily replaceable in case of damage.

The object is achieved in that the device consists of a first module and a second module, wherein the first module is detachably connected to the second module, wherein the first module comprises a process connection, the measuring wing and the metering wave, and wherein the second module at least the engine and the motor shaft includes.

The second module is removable regardless of the level in the container, while the first module is attached via the process connection in the container. The modular design allows easy replacement of elements that are in the second module, such as the motor. The first module is sealingly inserted into the container, so that it remains tightly closed during the removal of the second module. A complete or partial emptying of the container in case of a required replacement of the engine is thus no longer necessary in contrast to conventional rotary wing limit switches.

In a first embodiment of the solution according to the invention, the first module and the second module are configured such that a firm connection can be established between the first module and the second module. The solid connection is made for example by a locking fork. During measurement operation, the two modules are firmly connected. If replacement or repair of one element of the second module is necessary, the connection can be disconnected and the second module removed.

A preferred embodiment of the device according to the invention provides that the second module has a first chamber and a second chamber, which by a partition from each other wherein the first chamber contains the motor and the second chamber contains the coupling between the motor shaft and the metering shaft, and wherein the dividing wall has an opening through which the motor shaft protrudes from the first chamber into the second chamber. Through the second chamber separation between the process and the engine is realized. Preferably located in the first chamber in addition to the engine and switching contacts and other electrical components.

A development of the invention is that the second module is designed such that the first chamber is thermally decoupled from the container. The thermal decoupling is ensured for example by the partition, which is designed according to the required quality of the thermal decoupling according to thick or made of a particularly suitable material.

Conventional rotary vane limit switches have the disadvantage that they can only be used at moderate temperatures. The reason for this is that common AC motors can only be operated at temperatures below about 55 ° C. Since the motor of a rotary vane limit switch is thermally coupled to the process, the process temperature must therefore not exceed this temperature threshold. The thermal decoupling of the motor from the container and thus the process expands the field of application of the rotary vane limit switch to higher temperatures.

An advantageous embodiment includes that the coupling is designed such that at a predetermined load of the measuring blade, the connection between the Meßflügelwelle and the motor shaft is disconnected.

By separating the metering shaft from the motor shaft, the motor is protected from overloading. The separation takes place at a given load of the measuring wing, the amount of which depends on the load limit of the engine before it takes damage.

In a further advantageous embodiment of the solution according to the invention, the coupling is realized by at least one permanent magnet, which is arranged between the motor shaft and the measuring blade shaft. For example, a permanent magnet is detachably disposed between the motor shaft and the metering shaft. If the load on the measuring blade reaches or exceeds the specified load, the permanent magnet slips between the two shafts and thus disconnects them.

According to a further embodiment, the motor shaft and the measuring impeller shaft in the region of the coupling in each case a plate-shaped extension and the permanent magnet is disposed between the two plate-shaped projections, wherein the permanent magnet is adapted in diameter to the diameter of the plate-shaped extensions.

In a further embodiment of the device according to the invention, the coupling is designed as a spring clutch or as a spring disc clutch. At high temperatures, a coupling by a permanent magnet has a reduced stability, so that, inter alia, in the case of high process temperatures, the use of a spring clutch or a spring disc clutch makes sense. This is also designed so that it separates the connection between the measuring blade shaft and motor shaft at a given load on the measuring blade.

The invention will be explained in more detail with reference to the following figures.

1 shows a silo with two rotary vane limit switches according to the invention shown in section;

2a shows a cross section of the first module of a modular built-rotary-switch with magnetic coupling;

2 B shows a cross section of the second module of a modular design rotary vane limit switch with magnetic coupling.

In 1 is a container 15 , in particular a silo, shown on the wall of two modular rotary wing limit switches 20 are attached. The lower wing rotary limit switch 20 is in its individual parts first module 7 , second module 8th and locking fork 14 dissected, for example, the situation when replacing the second module 8th equivalent. The first module 7 with the measuring wing 1 is about the process connection 5 in the container 15 brought in. The above arranged rotary vane limit switch 20 is shown in the ready state, ie the two modules 7 . 8th are firmly connected. For example, the second module 8th on the first module 7 screwed or plugged, wherein the connector is secured by a locking mechanism. in this embodiment, the lock is by the locking fork 14 realized. The motor shaft 3 is with the metering shaft 4 over the clutch 6 connected.

2a and 2 B disclose a detailed view of a preferred embodiment of the first module 7 and the second module 8th a modular rotary vane limit switch with a substantially permanent magnet 12 realized magnetic coupling 6 , This shows 2a the first module 7 and 2 B the second module 8th in cross section.

The first module 7 consists of the measuring wing 1 , the measuring wing wave 4 , which with the measuring wing 1 is firmly connected and this drives to perform a rotary motion, as well as from the process connection 5 , The process connection 5 when inserting into the container 15 sealed for example with a flat seal D1 against the process. The measuring impeller shaft 4 is inside the process connection 5 rotatably mounted. So that no process medium through a possibly existing gap between the Meßwügelwelle 4 and the process connection 5 in the area outside the container 15 is between the measuring impeller shaft 4 and process connection 5 a sealing ring D2 attached.

The second module 8th is in a first chamber 10 and a second chamber 11 divided, the first chamber 10 the engine 2 contains. Preferably located in the first chamber 10 In addition, the contacts and switching elements of the evaluation for determining the reaching of the predetermined level (not shown here). The first chamber 10 is from the second chamber 11 through a partition 9 separated. The partition 9 has an opening through which the motor shaft 3 from the first chamber 10 in the second chamber 11 protrudes and which is sealed, so the first chamber 10 from the second chamber 11 is isolated. The second chamber 11 As a result, it forms a buffer between the process and the prevailing temperature and the first chamber 10 in which the engine is 2 is located so that the first chamber 10 thermally from the container 15 or the process is decoupled. This is advantageous because conventional AC motors can no longer be used at high temperatures above approximately 50 ° C. By this configuration of the second module 8th is the engine 2 not exposed to the process temperature, so it can be operated even when the process temperature is above that for the engine 2 acceptable threshold. Up to which temperature this applies is of course dependent on the quality of the thermal decoupling.

The second chamber 11 contains the end of the motor shaft 3 , which in this embodiment, a plate-shaped extension 13 having. This serves to couple to the permanent magnet 12 , wherein by the increased cross-sectional area better adhesion is achieved. The measuring impeller shaft 4 also has such a plate-shaped extension 13 on. The permanent magnet 12 , which preferably in its cross section at the plate-shaped extensions 13 is adjusted, couples the Meßflügelwelle 4 to the motor shaft 3 , Is the engine 2 In operation, the generated torque is applied to the motor shaft 3 and the meterwave shaft 4 transferred and the measuring wing 1 put in a rotary motion.

Meets contents on the measuring wing 1 , this is disturbed in its rotary motion. This has repercussions on the engine 2 , which the measuring wing 1 drives. In order to avoid damaging it at too high a load, which is below a certain load, which is below that for the engine 2 maximum compatible, the clutch 6 separated. In this embodiment, this is realized by the fact that the permanent magnet 12 between the two plate-shaped extensions 13 slips. Thus, none for the engine 2 dangerous force more of the measuring impeller shaft 4 on the engine 2 be transmitted. In an alternative embodiment, the clutch 6 designed as a spring force coupling. For example, in high temperature applications, the spring clutch is preferable to the magnetic clutch because the magnetic clutch loses grip at high temperatures. Analogous to the magnetic coupling, the connection between the measuring impeller shaft is also used for the spring-loaded coupling 4 and motor shaft 3 disconnected at a certain load.

The modular design of the rotary vane limit switch 20 offers the advantage that in the event that the engine 2 despite increased protection against damage must be replaced, for example, due to aging, only the second module 8th must be removed while the first module 7 in the container 15 remains. Because the first module 7 is configured by the seals D1, D2 such that the interior of the container 15 is sealed against the outside area, this is not emptying the container 15 required.

The firm connection between the first module 7 and the second module 8th For example, via a U-shaped locking fork 14 produced in which 1 is shown. The second module 8th is on the first module 7 plugged, the housing of the second module 8th with the process connection 5 of the first module 7 at least partially forms an overlap. The first module 7 has a circumferential groove 16 on while the case of the second module 8th two arranged on opposite sides and substantially parallel holes executed 17 having. Is the second module 8th on the first module 7 put on, are the holes 17 at a height with the groove 16 and form a channel, so to speak. The locking fork 14 engages through this channel and is secured against slipping out at the exit ends. Of course, this attachment mechanism is to be understood only as an example.

LIST OF REFERENCE NUMBERS

1

measuring vane

2

engine

3

motor shaft

4

Measuring vane shaft

5

process connection

6

clutch

7

First module

8th

Second module

9

partition wall

10

First chamber

11

Second Chamber

12

permanent magnet

13

Plate-shaped extension

14

locking fork

15

container

16

groove

17

drilling

20

Rotary paddle switch

D1

gasket

D2

seal

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

• US 4147906 [0005]
• EP 1357366 B1 [0005]

Claims (8)

Device for determining and / or monitoring a predetermined fill level of a bulk material in a container ( 15 ) with a measuring wing ( 1 ), which rotates in the container ( 15 ), an engine ( 2 ) for driving the measuring wing ( 1 ) and a shaft over which the measuring wing ( 1 ) with the engine ( 2 ), wherein the shaft is in a driving motor shaft ( 3 ) and a driven metering shaft ( 4 ) and wherein the motor shaft ( 3 ) and the measuring impeller shaft ( 4 ) via a coupling ( 6 ) are detachably connected to each other, characterized in that the device consists of a first module ( 7 ) and a second module ( 8th ), the first module ( 7 ) detachable with the second module ( 8th ), the first module ( 7 ) a process connection ( 5 ), the measuring wing ( 1 ) and the measuring impeller shaft ( 4 ), and wherein the second module ( 8th ) at least the engine ( 2 ) and the motor shaft ( 3 ). Device according to claim 1, characterized in that the first module ( 7 ) and the second module ( 8th ) are configured such that between the first module ( 7 ) and the second module ( 8th ) A solid connection can be produced. Device according to claim 1 or 2, characterized in that the second module ( 8th ) a first chamber ( 10 ) and a second chamber ( 11 ), which by a partition ( 9 ), the first chamber ( 10 ) the engine ( 2 ) and the second chamber ( 11 ) the coupling ( 6 ) between the motor shaft ( 3 ) and the measuring impeller shaft ( 4 ), and wherein the partition ( 9 ) has an opening through which the motor shaft ( 3 ) from the first chamber ( 10 ) into the second chamber ( 12 protrudes. Device according to claim 3, characterized in that the second module ( 8th ) is configured such that the first chamber ( 10 ) thermally from the container ( 15 ) is decoupled. Device according to at least one of the preceding claims, characterized in that the coupling ( 6 ) is configured such that at a predetermined load of the measuring blade ( 1 ) the connection between the measuring impeller shaft ( 4 ) and the motor shaft ( 3 ) is separated. Device according to at least one of the preceding claims, characterized in that the coupling ( 6 ) by at least one permanent magnet ( 12 ) is realized, which between the motor shaft ( 3 ) and the measuring impeller shaft ( 4 ) is arranged. Apparatus according to claim 6, characterized in that the motor shaft ( 3 ) and the measuring impeller shaft ( 4 ) in the region of the coupling ( 6 ) each have a plate-shaped extension ( 13 ), and that the permanent magnet ( 12 ) between the two plate-shaped projections ( 13 ), wherein the permanent magnet ( 12 ) in its diameter to the diameter of the plate-shaped extensions ( 13 ) is adjusted. Device according to claim 5, characterized in that the coupling ( 6 ) is designed as a spring clutch or as a spring disc clutch.

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