DE102017104919A1 - Density monitor with integrated low-pressure indicator and measuring bellows system for this purpose - Google Patents

Abstract

In order to advantageously use a density monitor when filling or during transport of a system to be monitored, the invention provides a density monitor (30) for monitoring a gas density in a gas space (19), with a first movable partition (36), which with a reference pressure to filling closed reference volume of the gas space (19) separates, a by the movement of the first partition (36) movable drive member (42) for driving a mechanical display device (44), a second movable partition (40) which the gas space (19) of a further chamber, wherein the first partition wall (36) and the second partition (40) via a stop (8, 11) limited relative to each other are movable and wherein the movable drive element (42) coupled to one of the partitions (36, 40) is such that it is movable relative to the other partition (36, 40) in a limited by the stop (8, 11) circumference.

Description

The invention relates to a density monitor for monitoring a gas density in a gas space with a first movable partition which separates a reference volume to be filled with a reference closed reference volume from the gas space and a movable by the movement of the first partition drive element for driving a mechanical display device. Furthermore, the invention relates to a measuring bellows system for such a density monitor.

Such a density monitor is known, for example, from the company brochure "SF ₆ Gas Monitoring" of Trafag AG with the imprint H70643b of October 2011. In this case, the first partition wall is arranged on a measuring bellows, in the interior of which the reference volume is located. One end of the measuring bellows is fixed in place, at the other end of the bellows, the partition wall is arranged. If the pressure in the gas volume increases compared to the reference volume, this leads to the movement of the dividing wall. To the partition a drive element in the form of a drive ram is attached, which has a pointer as indicator, which moves relative to a scale. The pointer indicates the respective gas density.

As known from the cited document, density monitors are used in particular for monitoring the density of the insulating gas - typically SF ₆ - of gas-insulated switchgear. The main task is the exact monitoring and representation of the temperature-compensated filling pressure of the system. This is realized by the precise reference chamber measuring system and the associated high-resolution main scale. However, this has the disadvantage that is limited due to the high resolution of the measuring range.

If one now wants to measure, for example for transports or the like, a lower pressure range within the gas space to be monitored, an additional measuring system with a lower resolution must be provided.

The object of the invention is to provide a density monitor and a measuring bellows system for this purpose, so that a larger field of application is made possible.

To achieve this object, the invention provides a density monitor with the features of claim 1 and a measuring bellows system for this purpose with the features of the independent claim.

Advantageous embodiments are the subject of the dependent claims.

According to a first aspect of the invention, the invention provides a density monitor for monitoring a gas density in a gas space
a first movable partition which separates a reference volume to be filled with a reference pressure from the gas space, a drive element movable by the movement of the first partition for driving a mechanical display device;
a second movable partition wall separating the gas space from another chamber, the first partition wall and the second partition wall being movable relative to each other via a stop, and wherein the movable drive element is coupled to one of the partition walls so as to be relative to the other partition wall is movable in a limited by the stop circumference.

It is preferred that the drive member is coupled to the second movable partition for co-co-movement, wherein the stop limits the movement of the second movable partition and the coupled drive member relative to the first movable partition wall.

It is preferred that the first movable partition wall is arranged on a first measuring bellows, which separates the reference volume from the gas space, and / or that the second movable partition wall is arranged on a second measuring bellows, which separates the gas space from the further chamber.

It is preferred that the first and the second measuring bellows are arranged concentrically with one another.

It is preferred that the first measuring bellows has an outer bellows and an inner bellows, which define the reference volume between them, and that the second measuring bellows is arranged inside the inner bellows of the first measuring bellows.

It is preferred that the drive element comprises a drive plunger which drives a pointer of a drive device.

It is preferred that the drive ram is arranged in the interior of the second measuring bellows.

A preferred embodiment of the density monitor has a drivable by the drive member display device which moves relative to a scale having a low pressure region and an adjacent high-pressure region, wherein the drive element and the display device are arranged and configured such that the display device upon detection or release of the stop between located in a transition between the low pressure area and the high pressure area.

It is preferred that the reference pressure in the reference volume is greater than the pressure in the further chamber and / or that the further chamber has ambient pressure.

According to a further aspect, the invention provides a measurement bellows system for a density monitor according to one of the above-described embodiments, comprising a first measurement bellows, which includes a reference volume for a reference pressure and a first movable partition which separates the reference volume from a gas space to be measured, a second Measuring bellows having a second movable partition which separates the gas space to be measured from another chamber, wherein the first and the second partition are limited relative to each other via a stop movable, and a movable drive member for driving a mechanical display device, wherein the movable drive element is coupled to one of the partitions, so that it is movable relative to the other partition in a limited by the stop circumference.

Preferred embodiments of the density monitor and of the measuring bellows system for this purpose provide a measuring device with which, on the one hand, the operation of a switchgear is to be monitored with high resolution and precisely the density of a gas within the gas space; during transport or when filling the switchgear - also another pressure range, especially a low pressure range, can be monitored.

This is preferably done with structurally simple and reliable mechanical means. In particular, both a lower pressure range and a higher pressure range can be displayed via a common display element.

• 1 eine schematische Übersichtsdarstellung einer bevorzugten Ausgestaltung eines Dichtewächters;
• 2 ein vergrößertes Detail eines Messbalgsystems des Dichtewächters von 1;
• 3 das Messbalgsystem von 2 mit einer Darstellung des mit dem zu überwachenden Gasraum einer Schaltanlage kommunizierenden Raumes;
• 4 das Messbalgsystem von 2 mit einer Hervorhebung eines Referenzvolumens; und
• 5 das Messbalgsystem von 2 mit einer Hervorhebung eines zweiten Messsystems für eine Niederdruckmessung.

An embodiment of the invention will be explained in more detail with reference to the accompanying drawings. It shows:

• 1 a schematic overview of a preferred embodiment of a density monitor;
• 2 an enlarged detail of a bellows system of the density monitor of 1 ;
• 3 the measuring bellows system of 2 with a representation of communicating with the monitored gas space of a switchgear room;
• 4 the measuring bellows system of 2 with a highlighting of a reference volume; and
• 5 the measuring bellows system of 2 with a highlighting of a second measuring system for a low pressure measurement.

In 1 is an embodiment of a density monitor 30 with a measuring bellows system 32 represented, wherein the measuring bellows system 32 in 2 is shown enlarged again.

The density guard 30 has a plant-side pressure connection 1 for connection to a system 12 which is to be filled with gas and whose gas density is to be monitored. For example, the attachment 12 a high-voltage switchgear, a high-voltage converter, a high-voltage pipeline, a switching device and / or a transformer. In the plant 12 there is investment gas 13 , which via the pressure connection 1 with an investment gas space 19 in a sensor housing 2 the density monitor is in fluid communication.

The measuring bellows system 32 is in the sensor housing 2 housed and has a reference chamber measuring system 20 , highlighted in 4 , filled with a reference gas 21 , and a low pressure measuring system 22 , highlighted in 5 , on.

The reference chamber measuring system 20 has a first measuring bellows 34 on, which is fixed at one end, here on a reference chamber lid 3 , is attached and at its other end a reference chamber floor 5 which is an example of a first partition wall 36 represents.

The first measuring bellows 34 has an outer bellows 4 and an inner bellows 6 on. The outer bellows 4 , the inner bellows 6 as the first partition 36 acting reference chamber floor 5 and the reference chamber lid 3 include one as a reference volume 38 with a predetermined reference pressure of a reference gas 21 to be filled reference chamber.

The low pressure measuring system 22 has a second measuring bellows 38 in the form of a low-pressure bellows 7 on.

The second measuring bellows 38 is concentric with the first measuring bellows 34 arranged. In particular, the low-pressure bellows 7 inside the inner bellows 6 arranged. At one end is the second measuring bellows 38 also stationary, for example in the region of the reference chamber lid 3 attached.

At the other end, the second measuring bellows 38 as a second movable partition 40 acting low pressure floor 9 on. This is to a drive element 42 coupled, whose movement via a transmission to a display device 44 is transmitted.

In the illustrated embodiment, the drive element 42 a drive plunger, for example in the form of a shift rod 10 , on. This is the driving element 42 to the common Movement to the second movable partition 40 coupled.

The through the reference chamber floor 5 formed first movable partition 36 and those through the low-pressure floor 9 formed second movable partition 40 are movable relative to each other to a limited extent. The movement is through an upper stop 11 in one direction and by another stop, for example in the form of a driver 8th , bounded in the other direction. About the driver 8th can be the second movable partition 40 when moving up in 2 the drive element 42 - Eg the shift rod 10 - take with you.

The shift rod 10 may be designed as disclosed in the aforementioned company publication "SF ₆ Gas Monitoring" Trafag AG. Accordingly, the shift rod 10 in a density monitor housing 14 (Manometer housing) when moving press switch (not shown). Next, the shift rod 10 a display device 44 in the form of a pointer 16 on a scale 15 move.

The scale 15 has a low pressure gauge 17 and as another area a high-resolution main scale 18 on.

Thus, the density monitor 30 for monitoring a gas density in a gas space 19 (in fluid communication with the system 12 ) and has the first movable partition wall 36 and the second movable partition 40 on. The first movable partition 36 separates with a reference gas 21 closed reference volume to be filled with specific reference pressure (see 4 ) of the in 3 highlighted gas space 19 , The second movable partition 40 separates the gas space 19 from one in 5 indicated chamber, which may be open to the environment and thus is at ambient pressure.

The first partition 36 is relative to the second partition 40 movable to a limited extent. This relative movement is caused by the at least one stop 8th . 11 limited. The drive element 42 which mechanically the display device 44 drives, is to one of the partitions, namely here the second partition 40 , coupled.

The following is the function of the density monitor 30 explained in more detail.

For a continuous representation of the entire pressure range with a scale 15 and a pointer 16 to provide two measuring systems 20 , 22 provided (see 2 ).

The two measuring systems 20 . 22 are operated one after the other. This ranges from displaying a low pressure on the low pressure gauge 17 by operation of the low-pressure measuring system 22 via an ad on the high-resolution main scale 18 by means of the high-resolution reference chamber measuring system 20 , where both measuring systems 20 . 22 over the same shift rod 10 acting on a measuring mechanism, which is the hub in a rotary motion of the pointer 16 transforms.

The high precision of the reference chamber measuring system 20 remains in this case compared to the known from the above-mentioned company publication density monitor.

As long as that in the reference chamber of the reference chamber measuring system 20 bottled reference gas 21 a higher pressure than the filling in the plant 19 has, is the power flow through the reference chamber measuring system 20 initially interrupted.

The shift rod 10 is only via the low-pressure measuring system 22 operated, which is the low-pressure bellows 7 , the driver 8th between selector rod and low pressure bottom 9 , the low-pressure floor 9 and the top stop 11 for low pressure. So the shift rod is using the low-pressure measuring system 22 pushed up.

Reach the investment gas 13 now the same or higher pressure as the reference gas 21 in the reference chamber, this is contracted, and over the driver 8th creates a power flow to the shift rod 10 , The low pressure measuring system 22 is pulled along, and thus moves the shift rod 10 further up and comes in the range of the high-resolution main scale 18 , Here the temperature compensated switching point setting range is displayed.

In the following, a concrete example of use will be described in more detail.

The reference chamber measuring system 20 has the reference chamber lid 3 , the outer bellows 4 the reference chamber, the reference chamber bottom 5 , the inner bellows 6 of the reference chamber and the driver 8th on. The reference volume thus formed is eg at 600 kPa rel. bottled.

For example, the system 12 transported to a destination, the user fills the density guard 30 his plant 12 with eg 200 kPa rel. from. On the display 15 the density guard 30 is now about the low-pressure measuring system 22 the value on the scale 15 , namely 200 kPa rel. displays. Does the user have his attachment 12 Installed at the destination, he fills this with his investment gas pressure, for example, 680 kPa rel. from. During filling, the readable pressure on the display increases 15 via the low-pressure measuring system 22 up to 600 kPa rel. - up to this point holds the reference gas 21 , which is filled with the same pressure, by means of the first bellows 34 on the other hand. As soon as the pressure in the gas space 19 higher than that in the reference chamber - reference gas 21 - becomes the reference chamber bottom 5 with the driver 8th pushed up, and by the entrainment of the low-pressure measuring system 22 becomes the shift rod 10 the stroke of the high-resolution reference chamber measuring system 20 take.

LIST OF REFERENCE NUMBERS

1

Pressure connection - on plant side

2

sensor housing

3

Reference chamber cover

4

Outer bellows (reference chamber)

5

Reference chamber floor

6

Inner bellows (reference chamber)

7

Low pressure bellows

8th

Driver shift rod / low pressure (example for stop)

9

Low pressure floor

10

shift rod

11

Upper stop low pressure (example for stop)

12

Installation (eg high-voltage switchgear, high-voltage converter, high-voltage pipeline, switchgear or transformer)

13

conditioning gas

14

Density Controller housing

15

scale

16

pointer

17

Low pressure gauge

18

high-resolution main scale (area)

19

Gas space (e.g.

20

Reference chamber measuring system

21

reference gas

22

Low pressure measurement system

30

density Controller

32

Messbalgsystem

34

first measuring bellows

36

first movable partition

38

second measuring bellows

40

second movable partition

42

driving element

44

display

Claims (10)

A density monitor (30) for monitoring a gas density in a gas space (19), comprising a first movable partition (36) separating a reference closed volume to be filled with a reference pressure from the gas space (19) by movement of the first partition wall (36) ) movable drive element (42) for driving a mechanical display device (44), a second movable partition (40) which separates the gas space (19) from another chamber, wherein the first partition (36) and the second partition (40) via a stop (8, 11) limited relative to each other are movable and wherein the movable drive member (42) is coupled to one of the partitions (36, 40) so that it relative to the other partition wall (36, 40) in one by the stop (8, 11) limited scope is movable. Density monitor (30) after Claim 1 characterized in that the drive member (42) is coupled to the second movable partition (40) for co-movement, the stop (8, 11) controlling the movement of the second movable partition (40) and the coupled drive member (42) relative to the first movable partition (36) limited. Density monitor (30) according to one of the preceding claims, characterized in that the first movable partition wall (36) on a first measuring bellows (34) is arranged, which separates the reference volume of the gas space (19), and / or that the second movable partition wall (40) is arranged on a second measuring bellows (38) which separates the gas space (19) from the further chamber. Density monitor (30) after Claim 3 , characterized in that the first and the second measuring bellows (34, 38) are arranged concentrically with each other. Density monitor (30) after Claim 4 , characterized in that the first measuring bellows (34) has an outer bellows (4) and an inner bellows (6) defining therebetween the reference volume, and that the second measuring bellows (38) within the inner bellows (6) of the first measuring bellows (34 ) is arranged. Density monitor (30) according to one of the preceding claims, characterized in that the drive element (42) has a drive tappet comprising a pointer of a drive means (44) drives. Density monitor (30) after Claim 6 and after Claim 5 , characterized in that the drive ram is arranged in the interior of the second measuring bellows (38). Density monitor (30) according to one of the preceding claims, characterized by a display device (44) which can be driven by the drive element (42) and which moves relative to a scale having a low-pressure region and an adjacent high-pressure region, the drive element (42) and the Display device (44) are arranged and designed such that the display device (44) upon detection or release of the stop (8, 11) is located between in a transition between the low pressure region and the high pressure region. Density monitor (30) according to one of the preceding claims, characterized in that the reference pressure in the reference volume is greater than the pressure in the further chamber and / or that the further chamber has ambient pressure. A density monitor (30) according to any one of the preceding claims, comprising a first measurement bellows (34) including a reference volume for a reference pressure and having a first movable partition (36) defining the reference volume of a gas space to be measured (FIG. 19), a second measuring bellows (38) having a second movable partition (40) which separates the gas space to be measured (19) from another chamber, wherein the first and the second partition wall (36, 40) via a stop (8, 11) are movable relative to each other limited, and a movable drive element (42) for driving a mechanical display device (44), wherein the movable drive element (42) is coupled to one of the partitions (36, 40) so that it relative to the other partition wall (36, 40) is movable in a limited by the stop (8, 11) circumference.

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