DE9001157U1 - Monitoring device for measuring fill levels - Google Patents

Description

BENE Wastewater Technology GmbH

Main Street 81

7590 Achern

monitoring device &zgr;üb Hessen of level honing

10

15

The invention relates to a device for measuring the level of media of different densities in a container, which are arranged one above the other to form one or more separating layers with different heights and edges, with a measuring device having at least one float for the position of a separating layer and/or the total level.

A large number of different measuring devices are already known for determining liquid stratification. For example, electrical measuring devices with measuring tips that protrude into the liquid are known, whereby the resistance between the electrodes is measured. Furthermore, floats that are tuned to different specific weights are known, which are equipped with magnets and work together with reed contacts arranged along the measuring section.

In addition, optical, thermoelectric and electronic measuring methods are also known.

Overall, the aforementioned methods are usually complex, expensive and/or not suitable for applications with an increased risk of contamination and environmental stress.
For this application, the required operational safety over a longer, control-free period is not always

ensured.

In practice, for the reasons mentioned above, one often restricts oneself to only a few measuring points, e.g. limit values. However, this only allows very limited control and does not provide an overview of intermediate situations.

A further problem with the measurement of flammable media, e.g. petrol, oil and the like, is that appropriate explosion prevention measures must be taken, which in turn increases the effort.

The object of the present invention is to create a monitoring device that can be used reliably with comparatively little effort and under difficult conditions. A practically continuous

Measurement should be possible. Finally,

It should be possible to use it without any problems in potentially explosive areas.

To achieve this object, the invention provides in particular

proposed that the device has at least one float provided with a pressure gauge and that the pressure gauge has a pneumatic supply line. This device enables a reliable position measurement of separating layers in liquids or a measurement of the Layer thickness above such a separation layer. The use of air as a measuring medium also simplifies handling in connection with explosive liquids or gases escaping from them, since no additional safety measures are required. The thickness of a layer above a separating layer can be measured by the correspondingly changing hydrostatic pressure. Despite the overall low effort, good measurement results can be achieved and it is also easy to transmit the measurement data to an evaluation unit separate from the measurement location. and display device possible.

A particularly advantageous combination is achieved when the pneumatic supply line is connected to the pressure gauge and to the float and forms a measuring supply line for the pressure gauge on the one hand and is also intended to change the height of the float on the other, with the pneumatic supply line preferably opening into the float which is open at the bottom. In this case, the hydrostatic pressure can be measured at different heights, whereby the float can be made to sink to the bottom or the like by releasing the air or filling it with liquid. A pressure measurement is then used for the hydrostatic pressure measurement - measurement above the bottom.

Additional embodiments of the invention are set out in the further subclaims. The invention and its essential details are explained in more detail below with reference to the drawings.

It shows:

Fig. 1 a separator system with a sludge trap, a

Separator and a control shaft as well as an evaluation, control and measuring device shown as a block circuit diagram,

Fig. 2 a separator with level monitoring device,

Fig. 3 Separator roughly corresponding to Figure E, but here with -OQ and 4 additionally with a safety flap closure,

Fig. 5 a separator with b'absaugung,

Fig. 6 a servo float in side view and 35

Fig. 7 a servo float in top view and

Fig. 8 schematic representations of various measuring processes up to 12.

A separator device 1 shown in Fig. 1 has a

Separator 2, a sludge trap 3 upstream of the separator 2 and a control trap 4 connected to the separator 2.

The sludge trap 3 is essentially formed by a container 5

with an inlet 6 and an outlet 7. The inlet and *

The AbIr.uf is arranged at approximately the same height. s

Within this container 5, solid particles in the liquid supplied at the inlet 6 ;·'. can be collected as

Settle sludge 8. - _v j The separator 2 also has a container 9 with a |» inlet 10 and an outlet 11. The outlet opening 12 is f;

Here, however, it is offset downwards compared to the inlet 10. .,.■

arranged so that no surface liquid can flow away

but liquid from a corresponding to the position of the |

Drain hole 12 corresponding depth. This liquid H

then enters the control point 4 and is transferred from there |j

leads. I

&igr; 25 ^ ^e Separator device 1 serves to separate several %

Media of different densities. This can be water, oil or oil-petrol mixtures and solid particles (contamination). Such oil or petrol separators are also referred to as coalescence separators.

gO As already mentioned, the solid particles contained in the mixture can be at least partially separated in the sludge trap 3. In the separator 2, further solid particles are then separated as sludge 8.

Due to the lower specific weight,

above the water 13 in Fig. 1 at the separator 2 dotted oil layer 14, which, however, cannot drain through the deeper drain opening 12, where water 13 emerges.

The oil layer 14 floating above the water layer 13 and delimited by the separating layer 15 (dotted line) increases in height over time, although the upper side 16 (liquid level) is largely determined by the height of the drain 11. As a result, the separating layer 15 migrates downwards as the thickness of the oil layer increases. With the help of a monitoring device designated as a whole by 17, the length of the separating layer can be measured and the separating layer 15 can be prevented from reaching the area of the drain opening 12 in good time.

This monitoring device 17 has a servo float 19a provided with a pressure gauge 18 (see also Fig. 7), which is designed or set as an interface float. This interface float 19a is immersed in oil and floats in water. With the help of the pressure gauge 18 located on the float, the oil layer height h 1 (see Fig. 2) can be measured by measuring the hydrostatic pressure at the separating layer 15. Since the total level of the liquid is determined by the position of the outlet 11, The position of the separating layer 15 within the container can be determined based on the measurement of the oil layer thickness h 1. As an additional control option for where the uppermost liquid level actually is, in addition to the measurement of the hydrostatic pressure at the separating layer 15, the hydrostatic pressure can be measured at a predetermined, constant height. In the example shown, this is done with the help of a single-tube 20, whose outlet opening 21 is at a distance h 2 from the bottom of the container.

&Idigr; 22 is arranged. At the bubble outlet 21, for the

h 35 Pressure measurement Gas is emitted and the required pressure

hydrostatic counterpressure is measured. Since the height h 2 remains the same, the height h 3 from the bubble opening 21 to the liquid top 16 can be determined using the hydrostatic pressure. The total filling level is then determined from the distance h 2 + the measured height h 3.

This additional total height measurement can be used to detect fluctuations in the liquid level 16. For example, it can be used to monitor whether the liquid level is lowering, for example due to a leak in the container 9. This would result in the oil layer 14, although it has not yet reached its maximum permissible thickness, reaching the area of the drain opening ) M and then flowing away.

A small pipe positioned with its outlet opening and connected to the servo float 19a is also used to measure the pressure at the separating layer 15 (Fig. 1 and 2). The pneumatic connection is made by a hose coil 23 in order to give the float 19a the necessary freedom of movement. In particular, a hose coil with low expansion forces is provided here in order to keep external forces acting on the float small.

Figures 6 and 7 show the specially designed servo float 19a, which maintains its position exactly even when subjected to external forces, e.g. through the hose coil 23, so that no measurement value distortion occurs. This servo float 19a has a pilot float 24 and a pot float 25 that is in control connection with it. The pot float 25 is open at the bottom and has a connection 26 on its top for the pneumatic connection (hose coil 23).

The control connection between the pilot float 24 and the pot float 25 is formed by a gas release valve 27 on the pot float 25, through which the buoyancy of the pot float is reduced in the event of a positional shift between the pilot float and the pot float.

mers is changed. The pilot float 24 is arranged approximately above the pot float 25 and coaxially to it. As can be seen in particular from Fig. 7, the pilot float is ring-shaped with a central opening for the passage of the hose turn 23 and a guide. The pilot float 24 has a mechanical connection to a valve part, in the embodiment to the valve body 29, which engages in the pot float from below. This has a downward-pointing shaft 30, which also serves as a sliding guide 28 between the pilot float 24 and the pot float. The valve seat 31, which works together with the valve body 29, is arranged on the top of the pot float 25. The arrangement of the valve 27 creates a 25 with air supply through the hose coil 23 a stable The float enters the floating position, whereby air bubbles out when the valve is slightly opened. If the pot float 25 is now influenced in its floating position by external forces, e.g. slightly raised by pulling on the hose coil 23, the valve 27 opens and the strengthens air flow. This results in the buoyancy of the pot float 25 is reduced and the pulling force on it is thus compensated. In the opposite case, where the pot float would sink in relation to the pilot float, the valve 27 closes and the pressure flowing in at connection 26 If the air were to flow, the air volume in the float 25 and hence its buoyancy would increase until a stable, force-compensated position is reached.

The hydrostatic pressure is measured according to the position of the float 25 located inside the pot. Liquid surface 33. This measured value must be corrected by the distance a 1 of the liquid surface 33 from the separating layer 15. This is done with the help of an evaluation, control and measuring device 3Λ, which is shown as a block in Fig. 1. Ar this measuring device are the pressure measuring points leading to the pressure measuring points,

&igr; pneumatic connections 35.

The relative position of the liquid surface 33 in the pot float 25 to the separating layer 15 fluctuates slightly depending on the tensile or compressive forces acting on the pot float 25. In practice, however, these fluctuations do not have a detrimental effect on the measurement result. It is also possible to include the tensile forces originating from the pot float 23, which depend on the hip position of the servo float 19a, in the calculation of the result. In addition, the height fluctuations of the liquid surface 33 can be kept small by a large cross-sectional area with a correspondingly large liquid surface 33, since volume changes are then only slight. in height. As a vertical guide for the float 19 or the servo A guide star 36 is provided for the float 19 a, which passes through the float or the pot float 25 and is fitted in the container 5 or 9. This passes through a pipe 37 inserted into the float and forms a "water feedthrough".

With the help of the float 19 (Fig. 1) or the servo float

19 a (Fig. 1 and 2) the height of a solid layer - sludge 8 - deposited on the bottom of the container can also be measured. For this application, the servo float 19a s -25 has foot-shaped support surfaces 38 (Fig. 6 and 7) on the underside of its pot float 25 for support on the top of the solid layer. To measure the sludge height, the pot float 25 and the air supply line 23 are completely emptied of air. The float sinks downwards until its support surfaces 38 rest on the top 39 (Fig. 1) of the sludge layer. At this height, air is blown in and the pressure is continuously measured. The pressure increases steadily because water has to be pressed downwards out of the hose coil 23. The pressure required for this is considerably greater than the measuring pressure (with a constant air supply volume).

ft » »&igr; it ff»

drove), especially due to the greater viscosity of water compared to air. When the water is pressed out of the supply hose coil and air flows into the pot float 25, the pressure drops. At this point in time, a pressure measurement is carried out, whereby the measured value is proportional to the distance to the liquid top 16 (Fig. 2 to 5). Since the total filling level is either due to the design or by measuring with the bubble tube, it can be used to determine the sludge height h 4. After blowing in Air, the servo foam 19a rises again i* . s to the separating layer 15.

In the area of the sludge trap 3 in Fig. 1 there is a float for determining the Sc \ -.amis ¹ ' ^s 'ne da;' se-te &iacgr; L t . which works in principle the same as the &tgr;&kgr;,*bscheide'· 2 located servo swimmer 19 a, a bar does not need to be trained as a service swimmer.

From the above-described functionality it can be seen that the pneumatic connection via the hose coil both to hydrostatic pressure measurement as well as for changing the !'"he position of the float. It should also be mentioned that the increased pressure for pushing water out of the air supply line can also be used to test it for airtightness.

The float can also be used to measure a solid layer as the top layer of media, e.g. fat. In this case, the float is positioned from below on the underside of the solid layer and the pressure is measured there. In conjunction with a total height measurement, again, both the layer thickness and the distance of the bottom from the bottom of the container are measured. In this case, the air is supplied to the float from below. On the servo float 19a, a suction device 40 (see Fig. 5) can also be attached with a protruding into the oil layer and on the pot. float 25 attached oil suction snorkels I should be provided.

This enables continuous operation of the separator, whereby the oil can be automatically sucked out once it reaches a certain layer thickness, controlled by the measuring and evaluation device 34 provided. 5

Figures 3 to 5 show oil separators 2 which have an opening 12a which is closed by a flap 41. The flap 41 is connected to an active float 19b which is connected to a pneumatic line. This pneumatic line can also be used to

iü matic connection, the hydrostatic pressure is measured and the float 19 b is positioned. In conjunction with the flap 41, this has the particular advantage that when the separating layer 15 between water and oil is reached at a lower limit, the float 19 b, which moves the flap 41 up to at this point in time in the open position (see Fig. 3 and 5) is lowered by releasing air and thus the flap closes practically without delay. A normal flap float would gradually move with the downwardly moving separating layer, so that only a slow

closing process. In addition, in this case, one would have to

In this case, for safety reasons, the lower limit value should be set higher to prevent oil from flowing out. This is no longer necessary thanks to the active flap float and its short closing time, so that a larger oil capacity can be used. In addition, the closing forces of the active flap float in the flooded state are greater than those of an air-filled float that moves with the separating layer. As can be seen in Fig. 3 and 4, the flap 41 has stops 42 for the open position (Fig. 3) and for the closed position. others are provided for the closed position (Fig. 4) of the flap 41. These defined end positions of the flap 41 also result in defined end positions of the float 19 b, so that this can also be used to measure the total liquid level, e.g. in conjunction with the servo float 19 a. The flap float 19b thus simultaneously replaces

nor the measuring device with the bubble tube 20 (see Fig. 2).

In Fig. 3 and 4, a filter 43 is connected upstream of the drain opening 12a with the flap 41. It should also be mentioned that a porous sintered material can be provided as a dirt filter in the gas outlet valve 27 of the servo float 19a to prevent blockage.

The evaluation control and measuring device 34 shown in Fig. 1 has

lü has several functional blocks. Within the functional block there are at least one air pump, in particular a diaphragm air pump, pressure-electric voltage converters, adjustable throttles, pneumatic valves and air filters. Block 45 contains a programmable logic controller for the measuring process, the display and for the alarm. Block 46 contains the control and display panel with bar graph displays for sludge height, water height and oil layer thickness. Block 47 contains the power supply and, if necessary, buffered batteries. In block 48, a measured value transmission can take place.

e.g. to a protocol device.

Block 49 contains a charge controller and a battery tester and has a mains connection 50. Finally, block 51 contains alarm contacts for external alarm triggering.

Figures 8 to 12 show a possible valve arrangement for a pressure measuring point, whereby the measuring point can be located at the end of a bubble tube or at a float. If all valves 32 a, 52 b, 52 c are not activated as in Fig. 8, air is blown out of the outlet opening 21, e.g. of a bubble tube 20, via the air coming from the pump to line 53.

Fig. 9 shows the valve position in which the bubble tube 21 is vented so that the liquid level in the tube rises to the liquid surface 16. If

the valve 52b and valve 52c are switched, an increased pressure due to the liquid line flow resistance can be measured with the help of a pressure gauge 54 connected to the valve 52a until the liquid column is pressed out of the bubble tube. During this During the increased pressure phase, an air leak test is also possible.

Fig. 10 shows the state where air comes out of the bubble opening 21 and the hydrostatic pressure and the flow resistance-related increased pressure according to the position of the liquid-

surface 16 can be measured. $ Fig. 11 shows a resting state with closed valves. Fig. 12 shows the state with closed valves 52 b and

52 c and opened valve 52 a , whereby the hydrostatic $

Pressure can be measured exactly according to the depth without i

increased pressure caused by flow resistance. In addition, 1

An air leak test is also possible. J

It should also be mentioned that each valve is individually controlled by the controller.

can be controlled. r

The pneumatic connecting lines between the evaluation %

The control and measuring device 34 and the separator, the sludge trap and also the control shaft can be up to 100 m long without influencing the ^measuring result, for example, and is thus practically independent of the line length. As can be seen in Fig. 1, Single-tubes 20 are provided in the sludge trap 3, the separator 2 and the inspection shaft 4 for measuring the total filling height.

It should also be mentioned that instead of the particularly simple and therefore advantageous single tube 20 or the like Bubble points as measuring points, other pressure sensors can be used. The measuring device according to the invention can also be used in combination with other known measuring devices, e.g. with resistance sensors, reed contact sensors or the like.

ALL features presented in the description, the claims and the drawing can be essential to the invention both individually and in any combination with one another.

- Expectations -

Claims (1)

14 Claims . Monitoring device for measuring the level of media of different densities in a container, which are arranged one above the other to form one or more separating layers, with a fastening device having at least one float for the position of a separating layer and/or the total level, characterized in that the device in at least one with &rgr; i &eegr;&rgr; m Urnek m e s s e r (18) provided float (19, 19 a, 19 b) and that the pressure gauge has a pneumatic supply line (23). 2. Device according to claim 1, characterized in that the pneumatic supply line (23) is connected to the pressure gauge (18) and to the float (19, 19a, 19b) and on the one hand forms a measuring supply line for the pressure gauge and on the other hand is provided for changing the height of the float and that the pneumatic supply line preferably opens into the float which is open at the bottom. 3. Device according to claim 1 or 2, characterized in that uö!) a further pneumatic pressure gauge with a pneumatic measuring line is provided, arranged at a constant height in the STner VCPuSSt iSmt &egr;", 4. Device according to one of claims ' ;■ . s 3, characterized in that the pressure gauges are designed as pneumatic pressure gauges with single-pipes (20) and pressure transducers connected thereto. 5. Device according to one of claims 1 to 4, characterized in that for the air supply to the bubble tube or the like attached to the float a hose coil (23) or the like, in particular with low expansion forces, is provided. 6. Device according to one of claims 1 to 5, characterized characterized in that the fixed inlet tube (20) or similar pressure gauge for the total filling level measurement is arranged with its end below the lowest filling level. 7. Device in particular according to one of claims 1 to 6, characterized in that the float is designed as a servo float (19 a) with a pilot float (24) and a Pot float (25) connected to the measuring and 2^5 air supply line and that the control connection is formed by a gas discharge valve (27) through which the buoyancy of the pot float can be changed when the position between the pilot float and the pot float is shifted. 8. Device according to claim 7, characterized in that the gas discharge valve (27) for the pot float (25) has a valve seat (31) and a valve body (29) cooperating therewith and that one of these valve parts is attached to the pilot float ( 24) and the other valve part is attached to the pot float (25) in such a way that the valve (27) closes when the pot float sinks relative to the pilot float. on 9. Device according to claim 7 or 8, characterized in that the pilot float (24) is approximately ring-shaped and is arranged approximately above the downwardly open pot float (25). 10. Device according to one of claims 7 to 9, characterized characterized in that the pilot float (24) has a has a mechanical connection to a valve part, preferably the valve body (29), which engages in the bottom of the pot float (25). 5 11. Device according to one of claims 7 to 10, characterized in that the valve body (49) is designed as a needle which extends between the upper pot base and the valve seat (31) arranged there, the needle shaft (30) of which preferably simultaneously serves as a sliding guide (28). -iseheri the pilot float and the pot scnir ■■ iner serves. ^ 12. Device according to one of claims 7 to 11, thereby gesnnreichnet that an approximately vertical guide for the servo float, preferably in the form of a Guide tube (37) in the pot float penetrating rod (36) is provided. 13. Device according to one of claims 7 to 12, characterized in that on the underside of the pot floating (25) Support surfaces (38) are provided for supporting on a solid layer upper side. 14. Device according to one of claims 7 to 13, characterized ( 25 characterized in that within a separator tank (9) with an outlet (12 a) which can be closed by a flap (41) and is arranged at a distance below the liquid surface, a flap float (19 b) connected to the flap (41) and whose buoyancy can be varied is provided. 15. Device according to claim 14, characterized in that the flap float (19 b) is connected to an air supply and discharge and preferably an air outlet opening on its underside, if necessary in the form •••a ·>·· &igr;··· ·■ at·· · ■ 'If " * * a throttle opening. 16. Device according to one of claims 1 to 15, characterized in that a suction device (40) for a liquid (14) located above the separating layer (15) is provided on the servo float (19a). Pat IW. Maucher) Patent Attorney