DE3312345A1 - Apparatus for the continuous measurement and/or monitoring of the degree of pollution of water - Google Patents

Abstract

The invention relates to an apparatus for the continuous measurement/monitoring of the degree of pollution of waste water which is discharged to surface water. This apparatus is provided with a measurement system having at least one closed measurement chamber to which a feed line and a discharge line are connected, the latter being connected in such a manner that on flow of liquid through the measurement chamber a certain liquid level is maintained in the measurement chamber. Furthermore, there is a superatmospheric pressure line connected to the measurement chamber which is responsible for a slight superatmospheric pressure in the measurement chamber during the measurement, which measurement is carried out using an ionisation detector, the single or multiple measurement head of which is provided with a blow-off apparatus and is connected to the ionisation chamber. The pollution in the vapour/gas mixture above the water in the measurement chamber is continuously detected by this detector and, depending on this, an electrical detection signal is given off which is a measure of the degree of pollution and additionally can be responsible on exceeding a pollution threshold for switching on alarms and emergency measures. <IMAGE>

Description

Applicant:

B.V. Rotterdamsche Electriciteitsmaatschappij v / h H. Croon & Co. Ski moon 20-22 Rotterdam. / NETHERLANDS '

Title:

Device for continuously measuring and / or monitoring the degree of contamination of water

Representative:

Patent attorneys

Dipl.-Ing. S. Schulze Horn M.Sc,

Dr. H. Hoffmeister

Goldstrasse 36

4400 Munster

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Device for continuous measurement and / or monitoring the degree of contamination of .water.

The invention relates to an apparatus for continuous Measuring and / or monitoring the degree of contamination of water, in particular waste water. ·

In modern industry, especially in oil, and chemical industry one often has to deal with the problem of the disposal of waste water. In the oil and chemical Industry, for example, uses river water as cooling water, which has to be discharged again afterwards. Even with the extraction When the oil is pumped up, a lot of water comes with it, which has to be drained off afterwards. Also in storage facilities for edible oils as well as chemical and hydrocarbon factories deal with waste water. -

When pumping back used cooling water and other waste water, surface water pollution is allowed due to the new law there should be no more than 30 ppm contamination. The same goes for removal of the water from the basic products. In order to master these problems, it is necessary with the to be discharged Regularly measure the concentration of impurities in wastewater before this water is returned to the environment will.

So far, no appropriate system has been available to do this on a continuous basis and one had to resort to periodic sampling of sewage samples to take. However, this is quite labor-intensive because separate patterns always have to be analyzed individually, ■ and besides, there is some danger, especially when shortly after a sample or series of samples, there is a sudden change in the contamination level of the

used water occurs, whereby water with an undesirable degree of contamination is temporarily removed should.

Such problems would be void if one were over had a measuring device that is able to carry out measurements quickly and continuously. Such a thing The system should meet the following specifications:

1) it must be usable in hazardous environments, e.g. in environments where hydrogen can occur,

2) it must be possible to measure a large amount of liquid in a short time,

3) the system must react very quickly, e.g. within 1/4 second,

4) it must be possible to use the equipment if necessary is easily calibrated at every moment, and

5) Preferably, the measuring system has to be such that entering and draining water can be measured at the same time. ■ ■ - ·

So far it has been shown that not a single measuring system has proven itself and one was therefore forced to use the system from periodic Maintain sampling.

In preparation for the present invention, an attempt was made continuous water pollution measurements using very sensitive ones currently available on the market Execute ionization measuring cells, it was surprisingly found that if you want to measure Water through a closed room fHessen Hess, while a slight overpressure was exerted on the surface of the water, a continuous measurement of the

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Impurity level was made possible. On the basis of these data, according to the invention, a device like the one at the outset was created described developed, which is characterized by a measuring system is, comprising at least one closed measuring chamber, to which a supply line and a discharge line are connected, the latter in such a way that when there is a flow a certain liquid level is maintained in the measuring chamber by liquid through the measuring chamber, an overpressure line connected to the measuring chamber for an adjustable, low overpressure in the measuring chamber takes care of during the measurement, and an Ionisat'ionsmesszelle, which is provided with a blow-off device single or multiple measuring head is connected to the ionization chamber and there is an impurity in the steam / Gas mixture is continuously detected over the water in the measuring chamber and, depending on this, an electrical detection signal gives away.

Thanks to the high sensitivity and the high measuring speed of modern ionization measuring cells, the response to variations in the level of contamination to be measured is particularly high. With regard to comparable and reproductive values, it is recommended that the supply line after the metering chamber is provided with a through flow meter and a regulating valve, so that the throughput ■ completely determined flow rate in the measuring chamber, '._'_._ -is. In the case of the invention, the liquid level in the measuring chamber can be kept relatively low, for example a few centimeters, the most favorable measuring conditions being to be determined empirically. To set a correct liquid level in the measuring chamber, the design can be such that the discharge line is connected to the bottom of the measuring chamber via a level control element.

Since the sensitivity of the ionization measuring cell, among other things, BATH ORIGINAL

Depending on the nature of the contamination (e.g. any hydrocarbon, chlorine, etc.) it is preferable that a good calibration facility is built into the system. For this purpose, it is provided according to the invention is that 'system to the supply pipe to the measuring chamber is connected an injection for injecting a calibration contamination. In this way, an operator can adjust the sensitivity of the apparatus to a presumed contamination present in the wastewater.

Since the ionization measuring cell emits an electrical detection signal depending on the measurement, this can be useful can be used for further signal processing. For this purpose, the ionization measuring set is connected to an electronic one in the invention Processing circuitry connected, which is again connected to an analog and / or digital display system is. With a view to continuous registration, the processing circuit can also be connected to a registration apparatus be committed.

With regard to appropriate monitoring, it is It is also recommended that the electronic processing circuit is connected to an alarm signal controller, so that the waste water discharge can be set instantly from a process line.

Although ^ he device according to the invention in principle with a single measuring chamber is possible, the supply line can be branched off from a process line for waste water, a more practical measuring system with a device obtained, which has two separate measuring systems, the second of which is a reference system, the one Measure reference liquid. The reference liquid exist as water with a certain permissible pollution level, preferably of the same type such as the contamination present in the waste water to be measured, but it can also be used as a reference fluid.

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water that is pumped from a river, for example and is used in the process whose wastewater is being measured and needs to be monitored.

In this case, the feed line of the measuring system is upstream the process line for wastewater is branched off, while the supply line of the reference system is branched off from the process line is branched for feed water.

In such designs, the ionization measuring sets of the measuring and reference system to a common electronic processing connected to the introduced measurement and reference signals from each other subtracts and the differential signals to the display system and / or returns the recorder.

It is also possible to design the device in this way that the display system and / or the recorder is a double system on which the signals of the electronic Processing circuit can be read both differentially and individually. With the double system described above the measuring system ^ and the reference system "can completely be separated from each other. In the case of an expedient compact design, however, it is preferable that the measuring chambers of the measuring system and the reference system subspaces of a common chambers provided with a longitudinal partition. '

A measuring device as described above has the following Characteristics:

1) the concentration of those dissolved in water or with water 4

mixed substances (flammable and non-flammable) can 1 to be measured; j

2) this concentration is measured continuously. 1 changes in concentrations in a very short time 1 can be observed; i

3) the possibility exists of several unknown substances by means of a multi-measuring head system, e.g. a five-measuring head esystem to recognize. Such a system has five different measuring cells, each with its own Have measurement area and can be switched;

4) on the pattern of the curve registered by the recorder, one can precisely determine the concentration of the liquid to be measured and the duration of this;

5) the measurement area is between 1 and ^ 5000 ppm and is depending on the substance to be measured by matching the measuring cell to what is selected with the help of calibration can be done;

6) the measuring system has a resolution of less than 1 second. on;

7) the measuring system is suitable for differential measurement, one of the liquids to be measured serving as a reference;

8) since measurements are not taken in the liquid phase but in the vapor phase, there is a logical connection between ppm and mg / m to be taken into account. This ratio is as follows:

273 M, 3 mg / m

.PP ^{m =} 22.4 T ■

, where 22.4 is the molar volume in liters-of a gas at 0 C and 1013 m bar and T is the absolute temperature.

If one ignores the temperature dependence, this formula can be simplified to

M, 3 - mq / m

PP ^ra = 24

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The invention will be explained in more detail using an exemplary embodiment with reference to the drawing. In the drawing shows:

"1 schematically shows an embodiment of the inventive Contraption; '

Fig. 2 is a plan view of the measuring chamber.

In Fig. 1 is an embodiment in a schematic manner a measuring device according to the invention shown. As can be seen, this comprises a measuring chamber 1 to which a supply line 2 and and a discharge line 3-connected are. The supply line 2 branches off from a line 4, the one process line is for wastewater from a wastewater-giving process. The supply line 2 contains an ammeter 5 and a control valve 6 in order to be able to set the permitted current precisely.

An overpressure line 7 is also attached to the measuring chamber 1 connected, which is provided with a pressure gauge 8 and a control element 9.

A measuring head 10 from an ionization measuring cell (also not shown) is also connected to the measuring chamber 1, with which the actual measurement is carried out. A calibration device 11 is also connected to the supply line 2 via a Line 12, which contains a needle valve 13, is connected.

To ensure that a constant liquid level is set in the measuring chamber during the measurement is, the discharge line 3 is connected to a level adjustment nipple 14, which ensures that a certain • Liquid level 15 in the measuring chamber 1 is maintained.

1 _s .

Besides this measuring system, the Device still has a corresponding reference system, the corresponding items with corresponding Bez.pgsziffer are marked in accented form. The outputs of the measuring heads 10 and 10 'are to an electronic processing circuit 16 connected, the output of which with a double indicator 17 and an alarm signal control 18 ■ and a double recorder 19 is connected.

The device described above functions as follows. Waste water that flows through the process sizing 4 becomes branched off via the supply line 2 of the measuring chamber 1, wherein the current is set precisely by means of the ammeter 5 and the setting valve 6. By adjusting the level adjustment device 14, a certain liquid level of about 4 cm occurs in the measuring chamber 1, while the overcurrent is discharged again via the discharge line "3" will.

During the flow of the liquid through the closed Measuring chamber 1 is ensured by means of the overpressure control 7, 8, 9 for a low air overpressure in the measuring chamber. The steam-air mixture above the water level 15 penetrates the measuring head 10 of the ionization measuring cell, which is expediently provided with a blow-off device (not shown) for continuous refreshment and desired air-vapor setting in that to be ionized Mixture cares.

As a result of the ionization, there is a detection of contamination that has been taken up in the wastewater and which is also present located in the vapor above the liquid in the measuring chamber. By correctly setting the low air pressure Above the liquid it was found that such a liquid evaporation occurs that that in the vapor existing contamination is easily measurable.

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In the embodiment shown, the measuring head is shown simply, but in practice several measuring heads can be used be present, the measurement sensitivity of which is set differently is to be able to detect different impurities. Used to calibrate such a measuring head the calibration device 11, via which a known impurity is added to the liquid in a known dosage can be used to check the setting of such a measuring head.

Such a measurement is now also carried out in the reference system (indicated with an accent), in which a reference liquid flows through the measuring chamber 1 'in the same way through the line 2' and in a measure determined by the flow meter 5 'and the setting tap 6' and is discharged via discharge line 3 ^1. The detection outputs of the measuring heads 10 and 10 'are connected to two inputs of the electronic processing circuit 16, which extracts these two signals from each other and forwards the difference signal to the display device, while also depending on whether a certain allowed The threshold the alarm circuit 18 is switched on in order, if necessary, to temporarily stop the discharge through the process line 4. The result is continuously recorded on the recording device 19.

If the process uses, for example, river water, which is pumped in first and then over after use, it is expedient Process line 4 is discharged, the supply line ^ 'der Reference measuring chamber 15 'to the supply process line of this supplied river water be connected. In this way you can immediately determine whether the payoff is to be carried out Water has a pollution level directly compared to the value point originally introduced.

In the embodiment shown, the display element 17, the can be both digital and analog, as a double instrument

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shown in order to be able to specify contamination levels determined separately in the measurement and reference system, while the registration apparatus 19 is also formed twice in such a manner. You can go to Wunr.ch in this way take both the individual draws and the differential readings of the two measurements.

As FIG. 2 shows, the measuring chamber 1 and the reference chamber 1 'form part of one and the same common measuring chamber, which is subdivided in the longitudinal direction ^ "via a partition 20. This allows a practical compact Training of the measuring chamber system can be obtained.

With the device described, numerous contaminants, with the exception of very heavy products such as Heating and lubricating oil between 4 C and higher without further precautions continuously with an accuracy of the order of magnitude of 1 ppm can be measured, whereby between 1 and 50 00 ppm can be measured. This makes it possible continuously to check whether the wastewater to be measured has a sufficiently low level of contamination around it to be able to discharge without further ado.

The calibration injection system 11, 12 is particularly useful, 13, which opens into the supply line in the liquid to be measured, which automatically creates a suction effect which depends on the speed of flow through the supply line. This can be an accurate Dosing done.

Although the invention is described above using an exemplary embodiment, it will be clear that changes and modifications are possible. The Moss and Referencing Chambers do not need to be connected to one another via a partition wall and also to the other individual parts numerous variations are possible.

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In addition to all kinds of sewage, the device can also be used for other systems, with it Are purity conditions with respect to water apparatus. For drinking water control it is in principle possible one according to the invention to use the device in this Fall, for example, simply, i.e. exclusively with one measuring system " and can be designed without a reference system.

Further modifications will become apparent to those skilled in the art of the above be clear.

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Claims (1)

Patent claims ü che ^ 1. Device for continuously measuring and / or monitoring the degree of contamination of water, especially waste water, characterized by a measuring system, comprising at least one closed measuring chamber to which a supply line and a discharge line are connected, the latter in such a way that when liquid flows through the measuring chamber ⁷ a certain liquid level is maintained in the measuring chamber, an overpressure line connected to the measuring chamber, which ensures an adjustable, low overpressure in the measuring chamber during the "measurement" / and an ionization measuring cell, whose single or multiple measuring head is provided with a discharge device to the ionization chamber I is connected and continuously detects the contamination in the steam / gas mixture above the water in the measuring chamber and emits an electrical detection signal as a function of this 2. Apparatus according to claim 1, characterized in that I that the supply line has an ammeter and a control valve contains. - " 3. Apparatus according to claim 1 or 2, characterized in that the discharge line on the bottom of the Measuring chamber is connected via a level adjustment element. 4. ν device according to claim 1, 2 or 3, characterized marked that .ein injection ■ system for injecting a calibration contamination is connected. 5. Device according to claim 1, 2, 3 or 4, characterized in that the ionization measuring cell is connected to an electronic Processing circuitry is connected to the connected to an analog and / or digital display system is. 6. Apparatus according to claim 5, characterized in that gckenn-r indicates that the electronic processing circuit is also connected to a recorder. 7. Device according to claim 5 or 6, thereby characterized in that the electronic processing circuit is connected to an alarm signal controller. 8. Device according to one of the preceding claims, characterized in that these two · separate Having measuring stars, the second of which is a reference system that measures a reference liquid. 9. Device according to claim 8, characterized in that that the ionization measuring cells of the measuring and reference systems are connected to a common electronic processing circuit are connected, which subtracts the introduced measurement and reference signals from each other, and a Differential signal to the display system and / or the Registrierapparafc- emits. 10. Apparatus according to claim 8 or 9, characterized in that the display system and / or the registration apparatus is a dual system on which the Signals of the electronic processing circuit can be read both differentially and individually. 41. Device according to one of claims 8-10, characterized in that the measuring chambers of the measuring system and the reference system subspaces of a common, with a chamber provided with a longitudinal partition. COPY [ 12. Device according to one of the preceding claims, characterized in that the supply line of the (first) measuring system is branched off from a process line for waste water. """ ■ - · 13. Device according to claims 8-IL and 12, characterized characterized in that the supply line of the reference system is branched off from a process line for supply water.