WO2001040745A1 - Device for measuring and monitoring the radiation capacity of the uv rays of a waste water disinfection installation - Google Patents

Abstract

The invention relates to a device for measuring and monitoring the radiation capacity of the UV radiators of a waste water disinfection installation. Said device comprises at least one sensor head (1) that adjoins the UV radiators when in operation and with a control device that is disposed separately from the radiators. Said sensor head (1) comprises, as one integral part, a sensor (3), an A/D converter (ADC) (5) and a digital programmable calibration component (4).

Description

Device for measuring and monitoring the radiation power of UV rays from a wastewater disinfection system

The present invention relates to a device for measuring and monitoring the radiation power of UV rays of a water disinfection system with the features of the preamble of claim 1.

Such monitoring devices are used in wastewater disinfection systems as well as in drinking water disinfection systems in order to guarantee compliance with a prescribed minimum UV dose rate for killing bacteria contained in the water. Such lower limits for the permissible dose rate in disinfection systems are usually prescribed for the operation of these systems. To monitor the radiation intensity emitted by the UV emitters, which decreases with increasing age of the UV emitter, so far only analog UV sensor heads have been used, which transmit the measurement result to a control unit via an analog measuring line.

To ensure constant operating data, it is necessary to regularly calibrate the analog sensor and the control unit connected to the sensor, or at least the analog input stage of the evaluation electronics as a whole, against a reference sensor. For this purpose, the calibration must either be carried out on site together with the permanently installed evaluation electronics, or the sensor is dismantled together with the evaluation electronics and the entire system is sent in for calibration.

Both calibration variants are very complex and therefore costly.

It is therefore an object of the present invention to improve a device for measuring and monitoring the radiation power of UV lamps in such a way that the sensor head used can be calibrated independently of the control unit.

This object is achieved by a device with the features of claim 1.

Because the sensor head in the structural unit comprises a sensor, an analog-digital converter (ADC) and a digitally programmable calibration device, the sensor head can be used independently of the downstream one Evaluation electronics of the control unit are calibrated against a reference sensor. The calibration is carried out in such a way that a defined digital value is transmitted for a specific UV intensity. Changes over time in the input side of the control and regulating device are therefore without influence on the measured value.

For official documentation purposes, it is advantageous if a programmable serial number memory is also available in the structural unit of the sensor head. Furthermore, a bus logic is advantageously provided for the sensor head, which enables an exchange of the various digital data for the ADC, the calibration device and possibly the serial number memory via a common line that is as simple as possible.

In practice it is advantageous if the calibration device is a non-volatile digital potentiometer. The bus logic, if provided, is preferably internal to the ADC, the

Calibration device and preferably also connected to the serial number memory.

For security against manipulation, the bus logic or the serial number memory is set up so that the serial number can only be written once. The serial number can be read as often as required.

Overall, the device is particularly susceptible to malfunctions in that all data is transmitted digitally between the sensor head and the control unit. The invention also relates to a method for operating a UV radiation sensor head, in which not only an analog measured value is read out by evaluation electronics arranged separately from the UV sensor head. Compared to these known methods, a method is to be created which enables the sensor head to be calibrated without simultaneous adjustment to the control or regulation electronics.

In the case of these methods according to the invention, it is provided that a total of two operating states can exist, namely

1. the reading out of digital signals that represent a UV intensity; and

2. Calibrating the UV sensor head in order to compare a UV intensity incident on the sensor with a signal provided for this purpose.

If it is further provided that a serial number of the sensor head is read out, simple and clear documentation is possible. Manipulation is made difficult or impossible if the process of writing the serial number memory can only be done once.

During calibration, provision can in particular be made to detect the incident intensity with a reference sensor; calculate a manipulated variable for a calibration module integrated in the sensor head; to write the calculated manipulated variable m into a memory of the calibration site; to detect the intensity of the incident UV radiation and the digital signal emitted by the sensor head to be calibrated to compare the target signal; to document the calibration process if the signal given matches the target signal or, if the signal given does not match the target signal, repeat the calibration from the first step.

The greatest possible freedom from interference is guaranteed if both the UV sensor to be calibrated and the reference sensor head are connected to a calibration and documentation device via a digital data bus during the calibration process.

In the following, an exemplary embodiment of the present invention is described with reference to the drawings.

Show it:

Figure 1: Em block diagram of the structural

Unit of integrated components of the sensor head according to the invention; such as

Figure 2: a schematic arrangement of a

Calibration device with which a sensor head according to the invention can be calibrated without the control or regulation device connected in operation.

1 shows a sensor head according to the invention as a block diagram. The sensor head comprises a housing 1 with a window 2 which is transparent to the radiation to be registered. In the housing there are a sensor 3, preferably in the form of a UV-sensitive photodiode, a calibration module 4, an analog-digital converter 5, a bus logic 6 and em Serial number memory 7. The bus logic 6 is connected via a digital line 10 to a remote control or regulation unit (not shown). Internally there is a digital connection with the ADC 5, a digital connection 12 with the calibration module 4 and a digital connection 13 with the

Serial number memory 7 provided. Analog connections 15 exist between the ADC 5 and the

Calibration module 4 and between the sensor 3 and the calibration module 4.

This digital sensor head is one with its housing 1 in the vicinity of a UV lamp

Waste water disinfection system mounted so that a UV radiation 16 to be measured falls through the window 2 onto the sensor 3. The analog signal of the sensor 3 is passed via the connection 15 to the calibration module 4, preferably in the form of a digital, non-volatile potentiometer. There the signal m is changed in a manner known per se and fed to the ADC 5. The digital signal generated there, which corresponds to the output value of the calibration module 4, goes to the bus logic 6 via the digital connection 11 and is transmitted via the data line 10 at the request of the control unit.

For calibration, the entire sensor head 1 is removed from the UV disinfection system without its downstream control or regulation unit and calibrated against a reference sensor. Such an arrangement is illustrated schematically in FIG. 2. There, the sensor 1 to be tested, like the reference sensor 20, is irradiated with UV radiation 16 from a UV radiation source 21, the wavelength and the intensity of the radiation 16 essentially corresponds to that in practical operation. The sensor heads 1 and 20 transmit their digital measurement data via data lines 22 to an calibration device 23, for example a suitably equipped computer. This in turn transfers the essential data recorded during the calibration process to a printer 24 or a similar output unit for documenting the calibration.

In particular, during the calibration in the arrangement according to FIG. 2, the radiation 16 will fall on the sensor 3 and generate a corresponding digital signal via the calibration module 4 and the ADC 5. This signal, like the serial number stored in the serial number memory 7, is transmitted to the calibration device 23 and the value of the signal emitted by the sensor head 1 is compared with that from the reference sensor head 20. If a discrepancy is found, a digital signal is transmitted via the data line 22 and the bus logic 6 via the internal connection 12 to the calibration module 4, which then gives the relationship between the signal that comes from the sensor 3 m and the calibration module 4 and the analog one Signal that is output from the calibration module 4 to the ADC 5 changes. In particular, this is possible with a 4 m calibration module of a digital programmable potentiometer with non-volatile memory.

The measuring cycle is now carried out again, the sensor 3 emitting the same analog signal when the UV radiation 16 is unchanged, which is now transformed in a new way by the calibration module 4 and via the ADC 5 to a new digital value is converted. This digital value should correspond to that which is output by the reference sensor head 20. If the calibration was successful, the calibration process is completed and documented together with the serial number of the sensor head 1 on the device 24. If the calibration was not yet successful, a new cycle m is run through in the manner described above.

Overall, this results in a device and method with which the UV sensor for

Waste water disinfection systems can be calibrated against a reference sensor at a location remote from the control or regulation unit, without the part of the evaluation electronics contained in the control or regulation unit having to be removed and sent in together with the sensor. This reduces assembly times, calibration times and transport costs.

The possibility of clearly describing the serial number memory of the sensor head 1 and reading it out during the calibration increases the process reliability.

The electronic components mentioned can be, for example, the following components available as standard:

- ADC 5: MAX 111 from Maxim;

- Calibration module 4: digital potentiometer DS1803-100 from DALLAS;

- Serial number memory 7: PROM N82S123AN from Philips; - Sensor 3: Photodiode CUV250 (UV-C) from OEC;

- Bus logic 6: GAL22V10B from LATTICE.

Since the sensor heads m of the application described have to be operated under water, there is the advantage over the known sensor heads that no opening of the housing 1 is required for a calibration and thus an original factory-made watertightness is maintained during the calibration.

Claims

P atent to sp 1.Device for measuring and monitoring the radiation power of UV emitters of a water disinfection system, with at least one sensor head (1) which is adjacent to the emitters during operation, and with a control or regulating unit arranged away from the emitters, since you can see that the sensor head (1) in the structural unit comprises a sensor (3), an analog-digital converter (ADC) (5) and a digitally programmable calibration module (4). 2. Device according to claim 1, d a d u r c h g e k e n n z e i c h n e t that in the sensor head (1) also provided serial number memory (7) 3. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that a bus logic (6) is provided in the sensor head (1). 4. Device according to one of the preceding claims, characterized in that the calibration module (4) is em non-volatile digital potentiometer. 5. Device according to one of the preceding claims 3 and 4, since you r ch ge kennzei ch net that the bus logic (6) internally connected to the ADC (5), the calibration module (4) and preferably also to the serial number memory (7) is. 6. Device according to one of the preceding claims, that the bus logic (6) is only set up for a one-time writing of a serial number in the serial number memory (7). 7. Device according to one of the preceding claims, that the transmission of signals between the sensor head (1) and the control unit takes place digitally. 8. Method for operating a UV radiation sensor head, so that the following operating states are provided: - Reading out digital signals that represent a UV intensity; - Calibrate the UV sensor head (1) to compare an incident UV intensity (16) on the sensor with a signal provided for this purpose. 9. The method according to claim 8, since it is known that the step is additionally provided to read out a serial number of the sensor head (1). 10. The method according to any one of the preceding claims, since du r ch ge ke nnzeic hn et that the step is additionally provided once, a Write a serial number memory (7) of the sensor head (1) that can only be written once. 11. The method as claimed in one of the preceding claims, that the following is provided in the calibration, - Detecting the incident intensity (16) with a reference sensor (20); - Calculating a manipulated variable for a calibration module (4) integrated in the sensor head (1); - Entering the calculated control value m into a memory of the calibration building system (4); - Detecting the intensity (16) and comparing the digital signal emitted by the sensor head (1) to be calibrated with the target signal; - Documentation of the calibration process if the signal emitted matches the target signal; or - Repeat the calibration from the first step. 12. The method according to any one of the preceding claims, since it is known that during the calibration process both the UV sensor head (1) to be calibrated and the reference sensor head (20) are connected via a digital data bus (22) are connected to a calibration and documentation device (23, 24). 13. The method according to any one of the preceding claims, since you mark that the housing of the sensor head (1) is not opened for a calibration process. 1/1

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