Method for analysing water and apparatus for carrying out the method.

p0001The invention relates to a method for analyzing water or other liquids, in particular rain water in rain collectors and an apparatus for performing this process.

p0002the precipitate monitor after system German Weather Service, Meteorological Observatory Hamburg is known. With his property measurements can be made, such as. For example, the detection of the electrical conductivity, the pH value and the amount of precipitation. The measurement of pH and electrical conductivity is carried out continuously. The water is then led to a bistable rocker, by means of the amount of rainfall and its intensity is measured. A possible precipitation is detected by a so-called rain sensor, which opens a capping over the hopper and at the end of the precipitate also closes again. Through an adjustable switch-off delay is a frequent opening and closing at the beginning and end of a precipitate is avoided.

p0003On the accuracy of measurement in the initial stages, when the rainfall is particularly polluted, greater demands are being placed. In addition, there is a need, the collected water for so prepare that subsequent analysis of organic substances and heavy metals without special preparation is especially possible.

p0004The invention is thus based on the object of finding a method and an apparatus for performing the method, with or with the greater accuracy of the measurement, particularly in the initial phase of a precipitate is obtained and or the subsequent treatment of the collected water allows.

p0005This object is achieved in that the water for the quantity measurement is first collected in at least one volumetric cell until a certain, always the same filling level before the thus collected water is passed respectively on subsequent Eigenschaftsmeßzelle.

p0006According to the invention carried out the subsequent measurements of properties, in particular the Leitfähigkeitsund pH measurements in portions, wherein the forwarded volumes can be dimensioned so small that a high resolution of the profile of the respective measured values ​​can be achieved over time. This is just in the initial stage of a precipitate of importance because the proton concentrations contained in the precipitate are initially very high and then approach a saturation value.

p0007Concretely, the amount of measurement take place in that the water is alternately accumulated in at least two parallel Volumenmeßzellen and passed alternately to the subsequent Eigenschaftsmeßzelle. With this method, the water is collected alternatingly in the one or in the other volumetric cell, wherein the switch in each case takes place when is reached at a volumetric cell the maximum water level and the water thus collected is passed on to the subsequent Eigenschaftsmeßzelle. In this manner, sufficient time for the subsequent measurements obtained despite small volumes in the Volumenmeßzellen.

p0008According to a further feature of the invention is proposed that the water is passed through an adsorption column for Entferung organic constituents and then collected. The organic components can then be analyzed. The water thus obtained is - free of organic contaminants and can be from rain collector directly to the analysis of inorganic pollutants in the laboratory, in particular heavy metal impurities, used - depending on the nature of the adsorption column.

p0009It is advantageous that the water is previously collected in a collecting container and then passed up to a specific residue through the adsorption column, so that the adsorption column is not damaged. In the event that the adsorption column begins to dry out, thus decreases the residual water in the reservoir below a certain level, it is provided to fill the adsorption column with distilled water. Conversely, the water should be passed through the adsorption column until they reach a certain maximum state, but at least at the end of each measurement. Thus, the water is passed through the adsorption column with an even flow, it should be drawn there.

p0010An apparatus for performing the method described above is according to the invention characterized in that the quantity measuring means is arranged in the flow direction in front of a Eigenschaftsmeßzelle and consists of at least one equipped with a level probe volumetric cell, which can be driven so that the water when reaching the fill level probe from the particular volumetric cell is let out and forwarded to Eigenschaftsmeßzelle.

p0011Advantageously, should be provided for the Mengenmeßeinrichtungen least two Volumenmeßzellen alternately by a control device controllable such that the inflow is only open to a respective volumetric cell and will be closed when it reaches the level probe in this volumetric cell and opened to another volumetric cell. This particularly convenient embodiment, time is gained for the subsequent measurements without the collecting water is interrupted.

p0012In a further embodiment of the invention it is proposed that an adsorption column for the removal and subsequent analysis of organic components is provided, and subsequently a collection container are connected downstream from which then the water can be taken without further preparation for analysis of inorganic pollutants, in particular heavy metal impurities in the laboratory. Appropriately, another collection vessel so that the water can be first collected before it is passed through the adsorption front of the adsorption column. For this purpose, the further collecting should equipped with a communicating with the controller level sensor for determining the minimum level and the adsorption column to be connected to a reservoir of distilled water, which inlet is opened by the control device when the fuel level sensor! Indicates a value below the minimum levels , In this way it is prevented that the adsorption drying out and becoming damaged.

p0013In addition, it is provided that the further collecting vessel is equipped with a level sensor for detecting a maximum level, which is connected via the control device with a pump for conveying the water through the adsorption column in such a way that the pump is set upon reaching the maximum level in operation. So according to the invention will first be accumulated water so that it is then conveyed continuously through the adsorption column. Otherwise, the pump is to be placed definitely in operation when a measurement is completed.

p0014According to the invention it is further provided that a three-way valve is provided for releasing a conduit to a waste water tank between a Eigenschaftsmeßzelle and the further collecting tank. This three-way valve should be controlled via the control device in such a way that only the Meßprobem pass into the further collecting tank.

p0015The inventive device is particularly suitable as precipitation collector to analyze the rainfall accordingly. To this end, the beginning and end of the measurement should be provided in a conventional manner, a rain sensor, determines. The rain sensor should be provided with a delay element to the completion of the measurement at a time interval after removal of the wetting, so the measurement is not interrupted frequently with little precipitation.

p0016In a particularly preferred embodiment, the apparatus comprises a removable storage element for the storage of data, in particular the date and time of each first wetting of the rain sensor, the date, time and number of filling a volumetric cell, the total rainfall and optionally the conductivity and the pH value and the date and time the end of scale. Such latches are known per se and can be removed readily from a precipitation collector and replaced by a new storage element, whereby the evaluation can then be performed in the laboratory.

p0017In the drawing, the invention is illustrated with reference to a precipitation collector, whose individual parts are symbolized by a block diagram.

p0018Precipitation collector has in a known manner to a hopper (1) - which is not shown here - is provided with a capping mechanism, for example, with an electric motor operable lid. Corresponding structures are generally known, for example, by the VDI Guidelines 3870 of July 1985. The cover mechanism is controlled by a precipitation sensor (2), will be given at its wetting with rain, snow, dew or like a pulse to the capping mechanism, so that the lid is removed from the hopper (1).

p0019The precipitation sensor (2) can additionally be provided with a heater to convert precipitation in the form of snow or frost in the liquid form.

p0020Below the collecting hopper (1), a filter (3) is arranged, which removed by filtering the water contained in the solid components. The water then passes to a three-way valve (4) via which it is routed according to its position in the first volumetric cell (5) or in the second volumetric cell (6). The Volumenmeßzellen (5, 6) are each provided with a maximum sensor (7, 8), which via a control device in the three-way valve (4) act in such a way that it in response of a maximum sensor (7 or 8) on the respective other volumetric cell (6 or 5) switches. At both Volumenmeßzellen (5, 6) to close each to a control valve (9, 10), the outputs of which lead to a conductivity cell (11). Such conductivity cells (11) are known per se, so that they require no further description.

p0021The output of the conductivity measuring cell (11) is controlled by a further control valve (12) to which a pH-measuring cell (13) is connected. Even such measuring cells are known in devices of the present type in.

p0022seen in the flow direction of the water after the pH-measuring cell (13) a further control valve (14) and a three-way valve (15) are arranged. An output of the three-way valve (15) leads to a waste water container (16), while the other output goes to a pump (17), via which the water to a collection container (18) is promoted. The collecting container (18) has a maximum sensor (19) and a minimum sensor (20). Behind the sump (18) is an adsorption column (21) is arranged, which is intended to extract organic pollutants from the water to be examined and then subsequently to feed an analysis. It can, for example, a filled with a polymeric adsorbent resin glass column as it is sold by the company. SERVA Feinbiochemika, D-6900 Heidelberg 1, under the trade name "Amberlite" example. For passing through the adsorption column (21) the water is sucked out by opening a control valve (22) by a downstream pump (23) from the container (20), then passes through the adsorption column (21) and then passes into a further collecting vessel (24).

p0023The conductivity cell (11) also has connection to a reservoir (25) is stored in the distilled water, which can be routed through a control valve (26) into the conductivity cell (11). The pH-measuring cell (13) is connected to a further storage container (27) via a control valve (28), wherein the reservoir (27) containing a calibration solution. Finally, a third reservoir (29) is present, whose output leads via a control valve (30) to the collecting container (18).

p0024To control the individual components of the above precipitation collector an electronic control device is provided which is equipped with a single-board computer with a Siemens microprocessor SAB 80535th The controller is powered by a Power Supply.

p0025After switching on the precipitation collector is first put into a standby state. For this purpose, the control valves (9, 10, 12, 14, 22, 26, 28, 30) placed in the starting position, ie closed. The three-way valve (4) is set to the first volumetric cell (5) and the three-way valve (15) to the effluent tank (16). At the same clock and timers are initialized. Then, the control valve (26) is opened so that distilled water from the reservoir (25) enters the conductivity cell (11) and then in the pH-measuring cell (13). Then, the control valve (28) is opened so that the pH-measuring cell (13) is filled with the calibration solution from the reservoir (27). There then takes place a test car of the two measuring cells (11, 13) with subsequent initialization. Precipitation collector is then in the standby state.

p0026In standby mode constantly precipitation sensor (2) and in the collection container (18) arranged minimum sensor (20) are queried. If the outcome of query that the minimum sensor (20) is no longer wetted, the control device opens the control valve (30) so that in the collecting container (18) distilled water from the reservoir (29) flows, which is then in the adsorption column (21) passes. In this way, the adsorption column (21) is saved from destruction.

p0027Now requires a precipitate, this precipitate from the sensor (2) is detected. It gives a pulse to the control device, so that its lid is opened. At the same date and time, and thus the temporal beginning of the storm event are stored. Further, the control valves (26, 12 and 14) are opened so that distilled water from the reservoir (25) through said conductivity cell (11), and the pH-measurement cell (13) flows. Prior to the retained at the end of a previous measurement sample to be measured is sucked into the collecting container (18) in the latter. If it is the first rain event after switching, the then remaining in the pH-measuring cell calibration solution is washed with distilled water. Over the three-way valve (15) reach the distilled water and optionally calibration solution into the waste container (14). After the lid of the collecting hopper (1) is opening the flushing of the conductivity and the pH-measuring cells (11, 13) by closing the control valves (12 and 14, 26) terminated.

p0028It then queries whether the first volumetric cell (5) is filled. If this is the case, the water by opening the control valve (9) is introduced into the conductivity cell (11), while fresh calibration solution from the reservoir (27) is filled in the pH-measuring cell (13).

p0029If the first volumetric cell (5) is not filled, the control valve (26) is actuated first again so that the Leitfähigeitsmeßzelle (11) is refilled with distilled water. The same happens with the control valve (24) so ​​that fresh calibration solution passes into the pH-measuring cell (11). now reached the water in the first volumetric cell (5) the maximum sensor (7), the three-way valve (4) is switched to the second volumetric cell (6), so that the subsequently flowing water is collected in this volumetric cell (6). Simultaneously, the control valve (9) is opened so that the volumetric cell in the first (5) Accumulated water can flow into the conductivity cell (11). Date, time and number of filling are stored at the same time. Before the water enters the conductivity cell (11), this as well as the pH-measuring cell (13) are discharged into the waste water tank (16). The pH-measuring cell (13) is then immediately re-filled with a calibration after the control valves (12) and (14) have been closed.

p0030The volumetric cell from the first (5) coming water is then analyzed for its conductivity. For this purpose, as long as values ​​are queried until they are stable or the available measurement time has expired. The average value is then stored with the time. Thereafter, the pH-measuring cell (13) is emptied by opening the control valve (14) to the waste water container (16) and filled by activating the control valve (12) with that from the conductivity cell (11) coming water. At the same time closes the control valve (14) and the three-way valve (15) is switched in the direction of the collecting container. Then the pH value is measured and stored after reaching a stable value with time.

p0031The pH measurement and conductivity measurement should not take longer than three minutes together. If no stable value is reached within this time, the last measured value is stored with an indication of the instability.

p0032By leaving the water from the conductivity cell (11) is checked by the control device if the second volumetric cell (6) is already full. If this is not the case, distilled water is filled into the conductivity cell (11) by activating the control valve (26) again so that it does not dry out. If the second volumetric cell (6) already full and has therefore addressed already the maximum sensor (8) for the purpose of conversion of the three-way valve (4) in their water collected by operating the control valve (10) is conducted immediately in the conductivity measuring cell (11), where it remains until the water from the first volumetric cell (5) leaves the pH-measuring cell (13). The water in the pH-measuring cell (13) is then sucked by the pump (17) into the collecting container (18).

p0033By repeating the above sequence, the collection container (18) filled until the maximum sensor (19) responds. This is made by opening the control valve (22), the pump (23) in operation, so that in the collecting container (18) the water present through adsorption column (21) into the final storage tank (24) is sucked. In the adsorption column (21), the water is free of organic contaminants, so that it is suitable for heavy metal analysis after conversion into the sump (24).

p0034If the sump (18) to above the maximum sensor (19) is filled, it will be evacuated during the next measuring operation with the pump (19) on the adsorption column (17) until the response of the minimum sensor (27). Subsequently, the control valve (22) is closed again.

p0035The end of a storm event is detected by the precipitation sensor (2), because he is no longer wet. By a timer two minutes is awaited now. If there is no more rain in this time, the lid of the collecting hopper (1) is closed and precipitation collectors will return to the standby mode. The last water remains in the pH-measuring cell (11), while the conductivity cell (11) is filled with distilled water from the reservoir (25).