Ammonium analyzer configuration
The ammonium analyzer configuration addresses electrolyte evaporation issues by using an electronic controller and depletion detection module to extend maintenance intervals and maintain accurate measurements.
Patent Information
- Application Number
- JP2025574517
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-07-06
- Filing Date
- 2024-06-25
- Publication Date
- 2026-07-13
Smart Images
Figure 2026523195000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an ammonium analyzer configuration having a gas selective electrode unit with an electrolyte chamber housing filled with an electrolyte, and also to a method for determining the actual volume of the electrolyte in the electrolyte chamber housing of the gas selective electrode unit.
Background Art
[0002] A typical ammonium analyzer configuration includes a gas selective electrode unit immersed in a sample chamber filled with a chamber liquid that is a sample liquid or a calibration liquid. The gas selective electrode unit is provided with an electrolyte chamber housing filled with an electrolyte, and also with a measurement electrode element that directly contacts the electrolyte. The electrolyte chamber housing is provided with a gas sensitive membrane that separates the electrolyte in the electrolyte chamber housing from the chamber liquid in the sample chamber. Usually, the gas sensitive membrane is very thin and mechanically sensitive to the pressure difference on the gas sensitive membrane. Therefore, the electrolyte chamber housing is provided with a ventilation opening so that the gas cushion on the electrolyte always has a constant atmospheric pressure.
[0003] However, the electrolyte constantly evaporates through the ventilation opening so that the electrolyte volume in the electrolyte chamber housing constantly decreases.
[0004] To ensure certain conditions and enable an accurate determination of the ammonium concentration, the gas selective electrode unit is maintained at a constant temperature, for example 45°C, so that the evaporation of the electrolyte is relatively high.
[0005] As a result, the ammonium analyzer configuration has to be calibrated, for example, daily and regularly. Another result of the constant evaporation of the electrolyte is the fact that the electrolyte will eventually run out. However, it is difficult to determine the electrolyte volume with a suitable sensor. In practice, the electrolyte chamber housing is refilled with electrolyte at regular maintenance intervals, for example every 90 days. [Overview of the Initiative] [Problems that the invention aims to solve]
[0006] The object of the present invention is to provide an ammonium analyzer configuration equipped with a gas-selective electrode unit, and a method for providing high reliability and a long maintenance interval for the gas-selective electrode unit. [Means for solving the problem]
[0007] This objective is addressed by the present invention through an ammonium analyzer configuration having the features of claim 1, and a method for determining the actual volume of the electrolyte in an ammonium analyzer configuration having the features of claim 7.
[0008] The ammonium analyzer configuration according to the present invention includes an electronic controller and a measuring unit controlled by the electronic controller. The ammonium analyzer configuration may be a laboratory device, but is preferably a process device that requires the longest possible maintenance interval.
[0009] The measurement unit includes a sample chamber that, in addition to the reagent solution, is filled with a chamber liquid which is a sample solution derived from a sample solution site, such as a water basin in a water treatment plant, or a calibration solution for performing a calibration operation.
[0010] The measuring unit also includes a gas-selective electrode unit having an electrolyte chamber housing filled with a certain volume of electrolyte. The electrolyte chamber housing is not completely liquid-tight and has vents to ensure that the gas pressure of the gas cushion within the electrolyte chamber housing is always atmospheric pressure.
[0011] The gas-selective electrode unit comprises a reference electrode element that is in direct contact with the electrolyte. The reference electrode element can be of any suitable type. The reference electrode element is electrically connected to the measurement signal evaluation module.
[0012] The electrolyte chamber housing is provided with a gas-sensitive membrane that directly separates the electrolyte within the electrolyte chamber housing from the chamber liquid in the sample chamber. The gas-sensitive membrane can be made of any suitable material, for example, silicone. Preferably, the gas-sensitive membrane is made of PTFE (polytetrafluoroethylene).
[0013] The gas-selective electrode unit also includes a separate measuring electrode element that is in direct contact with the electrolyte in the electrolyte chamber housing. The gas-selective electrode unit is always immersed in the chamber fluid, at least in part.
[0014] Preferably, the sensing surface of the measuring electrode element is located very close to the gas-sensitive film, but is not in direct contact with the gas-sensitive film, such that a thin layer of electrolyte is provided between the sensing surface of the measuring electrode element and the gas-sensitive film. More preferably, this thin electrolyte layer has a volume of less than 1 ml.
[0015] The ammonium analyzer configuration includes a calibration solution container, which contains a calibration solution that is pumped from the calibration solution container into the sample chamber, for example, when a calibration operation is started on a daily basis. Preferably, the calibration solution has an ammonium standard concentration of at least 5 mg / l.
[0016] The electronic controller includes a measurement signal evaluation module electrically connected to a reference electrode element and a gas-selective electrode unit to generate the difference in measured values.
[0017] The electronic controller also includes a calibration module that generates calibration solution measurements when the sample chamber is filled with calibration solution. These calibration solution measurements are crucial for the measurement signal evaluation module to provide accurate measurements. The measurement signal evaluation module typically generates voltages in the range of -300mV to +300mV as measurements for a measurement range of ammonium (NH4-N) from 0 to 1000 mg / l.
[0018] The electronic controller also includes an electrolyte depletion detection module equipped with a depletion graph memory for storing calibration / depletion graphs. The calibration / depletion graph describes the relationship between the calibration fluid measurement and the absolute actual volume of electrolyte in the gas-selective electrode unit, or other relationships between the actual volume of electrolyte in the gas-selective electrode unit and the calibration fluid measurement. Typically, the calibration fluid measurement increases as the volume of electrolyte in the electrolyte chamber housing decreases.
[0019] The electrolyte depletion detection module is signal-connected to the calibration module. When a calibration operation is performed, the electrolyte depletion detection module determines the actual volume of electrolyte in the electrolyte chamber housing based on the actual calibration measurements and the calibration / depletion graph. The electronic controller can handle the determined actual volume of electrolyte in different ways; for example, it can send a warning signal when the electrolyte volume reaches a minimum volume and the electrolyte chamber housing needs to be refilled with electrolyte. As a result, a fixed maintenance interval with an appropriate safety margin is not required, and in practice, the maintenance interval for refilling the electrolyte chamber housing with electrolyte can be extended from 90 days to a maximum of 180 days.
[0020] Preferably, the measuring unit is equipped with a heating device and a temperature sensor, and the electronic controller includes a heating control module for controlling the temperature of the gas-selective electrode unit to a constant set temperature of at least 30°C, more preferably in the range of 35°C to 45°C. The reliability and accuracy of ammonium concentration measurement in an ammonium analyzer configuration depend heavily on the temperatures of the electrolyte, calibration solution, and sample solution.
[0021] Therefore, a constant temperature in the measurement unit is essential. As a secondary effect, a constant temperature in the measurement unit keeps the evaporation of the electrolyte in the electrolyte chamber relatively constant, and also makes other degradation effects of the electrolyte predictable. This results in the fact that one calibration / depletion graph is sufficient to predict the electrolyte volume based on the calibration solution measurement.
[0022] Preferably, the calibration / depletion graph shows the relationship of the electrolyte volume in the electrolyte chamber housing with respect to the difference between the initial calibration measurement value and the actual calibration measurement value. The initial calibration measurement value is the first calibration measurement value after a new or refilled gas selective electrode unit has been operated. More preferably, the initial calibration measurement value can be the average value of two or more consecutive initial calibration measurements.
[0023] Preferably, the calibration solution has an ammonium standard concentration of at least 5 mg / l. The higher the ammonium standard concentration of the calibration solution, the more reliable the determination of the actual volume of the electrolyte.
[0024] Preferably, the measurement signal evaluation module generates an ammonium concentration value based on the actual calibration solution measurement value.
[0025] Preferably, the ammonium analyzer configuration is provided with a reagent liquid tank, which contains a reagent liquid, and an appropriate volume of which is pumped to the sample chamber to react with the sample liquid or the calibration solution in the sample chamber.
[0026] One embodiment of the present invention will be described with reference to the accompanying drawings.
Brief Description of the Drawings
[0027] [Figure 1] A schematic diagram of an ammonium analyzer configuration including a gas selective electrode unit and an electronic controller, the electronic controller including a calibration module with an electrolyte depletion determination module, the electrolyte depletion determination module including a depletion graph memory for storing a calibration / depletion graph. [Figure 2] Shows the calibration / depletion graph stored in the depletion graph memory.
Modes for Carrying Out the Invention
[0028] Figure 1 schematically shows a land-based ammonium analyzer configuration 10, which is typically a process analyzer configuration. The ammonium analyzer configuration 10 determines the ammonium concentration in a water tank 12, which may be part of a water treatment plant. The water tank 12 is filled with a sample liquid 23, which can be pumped from the water tank 12 to a measuring unit 20 by a liquid pump 50.
[0029] The ammonium analyzer configuration 10 includes a first calibration solution container 42 containing a first calibration solution 43, and a second calibration solution container 44 containing a second calibration solution 45. The first calibration solution 43 in the first calibration solution container 42 has an ammonium concentration of, for example, 10 mg / l, and the second calibration solution 45 has a relatively low ammonium concentration of, for example, 1.0 mg / l.
[0030] The ammonium analyzer configuration 10 is provided with two three-way valves 51 and 52 for selectively guiding the sample solution 23, the first calibration solution 43, or the second calibration solution 45 to the sample inlet opening 24 of the sample chamber 22 via a liquid line between the water tank 12 and the sample chamber 22 of the measurement unit 20, and via a liquid pump 50. The ammonium analyzer configuration 10 is also provided with a waste liquid pump 53 for pumping the chamber liquid 22' in the sample chamber 22 to a waste liquid tank 40 where waste liquid 40' is accumulated after the measurement operation.
[0031] The ammonium analyzer configuration 10 includes a reagent tank 46 containing a reagent solution 47 that can be pumped to the measurement unit 20 by a reagent pump 53. The reagent solution 47 is preferably an alkaline solution, such as NaOH.
[0032] The measurement unit 20 comprises a sample chamber 22 filled with a chamber solution 22' which is substantially reagent solution 47 plus sample solution 23, or either calibration solution 43, 45; a reference electrode element 28 which may be of any suitable type; and a gas-selective electrode unit 30. Both electrode units 28, 30 are immersed in the chamber solution 22', at least in part.
[0033] The gas-selective electrode unit 30 comprises an electrolyte chamber housing 31 made of glass or plastic, which is filled with a suitable electrolyte 34 having an electrolyte level 34'. A new or refilled gas-selective electrode unit 30 contains 11 ml of electrolyte 34. The electrolyte 34 may have a concentration of, for example, 100 mmol / l of ammonium chloride, or for lower measurement ranges, a concentration of 2.0 mmol / l of ammonium chloride.
[0034] The electrolyte chamber housing 31 has a ventilation opening 37 at its top to allow the electrolyte 34 to constantly evaporate through it. The electrolyte chamber housing 31 has a gas-sensitive membrane 38 at its bottom, which is made of PTFE and separates the electrolyte 34 inside the electrolyte chamber housing 31 from the chamber liquid 22' inside the sample chamber 22.
[0035] The gas-selective electrode unit 30 also includes a measuring electrode element 32 that is in direct contact with a thin electrolyte layer 34" of a small amount of electrolyte 34, for example 10 μl, which is provided between the distal sensor surface of the measuring electrode element 32 and the gas-sensitive film 38.
[0036] The measurement unit 20 is equipped with an electric heating device 39 and a temperature sensor 59, both of which are electrically connected to the heating control module 70 in order to indirectly control and maintain the temperature of the gas-selective electrode unit 30 at a constant temperature T of 45°C.
[0037] The electronic controller 60 includes a measurement signal evaluation module 64, which is electrically connected to the reference electrode element 28 and the gas-selective electrode unit 30 to generate a measurement value U, which is the voltage difference between the reference electrode element 28 and the gas-selective electrode unit 30. The electronic controller 60 generates an ammonium concentration value based on the measurement value U.
[0038] The electronic controller 60 includes a calibration module 66, an electrolyte depletion determination module 62, a depletion graph memory 68 for storing the calibration / depletion graph 100, and a monitor 69.
[0039] The calibration module 66 controls and starts a calibration operation, for example, once a day. When the calibration module 66 starts the calibration operation, the first calibration solution 43 is pumped into the sample chamber 22, and an appropriate amount of reagent solution 47 is also pumped into the sample chamber 22. The dissolved ammonium ions are then converted into ammonia gas, which passes through the gas-sensitive membrane 38 and causes a potential change at the measuring electrode element 32.
[0040] After a few minutes, the measurement signal evaluation module 64 is instructed to generate a calibration solution measurement value U43, which is a voltage value that is the potential difference between the reference electrode element 28 and the measurement electrode element 32.
[0041] Subsequently, a calibration run is initiated using the second calibration solution 45, and the second calibration solution measurement value U45 is obtained. Both calibration solution measurement values U43 and U45 are stored and used for ammonium measurement and determination over the next 24 hours.
[0042] The stored first calibration solution measurement value U43 is also used by the electrolyte depletion determination module 62 to determine the volume V34 of the electrolyte 34 in the electrolyte chamber housing 31. The electrolyte depletion determination module 62 stores this value in the depletion graph memory 68 and determines the corresponding electrolyte volume V34 from the calibration / depletion graph 100 shown in Figure 2.
[0043] The actual electrolyte volume V34 is displayed on the display 69. If the actual electrolyte volume V34 is about to be depleted, the electrolyte depletion detection module 62 displays a maintenance recommendation on the display 69. The relevant depletion of the electrolyte volume V34 is achieved, for example, at 3.0 ml.
Claims
1. An ammonium analyzer configuration (10) comprising an electronic controller (60) and a measuring unit (20), The aforementioned measuring unit (20) A sample chamber (23) filled with a chamber solution (22') which is either a sample solution (23) or a calibration solution (43), A gas-selective electrode unit (30) comprising an electrolyte chamber housing (31) filled with an electrolyte (34), A reference electrode element (28) that is in direct contact with the electrolyte (34), A gas-sensitive membrane (38) separates the electrolyte (34) from the chamber liquid (22'), A measuring electrode element (32) that is in direct contact with the electrolyte (34), The ventilation opening (37) in the electrolyte chamber housing (31), Equipped with, A calibration solution container (42) containing a calibration solution (43) is provided. The electronic controller (60) includes a measurement signal evaluation module (64) connected to the reference electrode element (28) and the gas-selective electrode unit (30) for generating a measurement value (U), The electronic controller (60) includes a calibration module (66) that generates a calibration solution measurement value (U43) when the sample chamber (22) is filled with the calibration solution (43), An electrolyte depletion determination module (62) is provided, which includes a depletion graph memory (68) for storing a calibration / depletion graph (100). The electrolyte depletion detection module (62) is signal-connected to the calibration module (66), The electrolyte depletion determination module (62) is an ammonium analyzer configuration (10) that determines the actual volume (V34) of the electrolyte (34) based on the calibration measurement value (U43) and the calibration / depletion graph (100).
2. The ammonium analyzer configuration (10) according to claim 1, wherein the measuring unit (20) is provided with a heating device (39) and a temperature sensor (59), and the electronic controller (60) includes a heating control module (70) for controlling the temperature of the gas-selective electrode unit (30) to a constant set temperature T of at least 30°C.
3. The ammonium analyzer configuration (10) according to claim 1 or 2, wherein the gas-sensitive membrane (38) is made of PTFE.
4. The calibration / depletion graph (100) shows the initial calibration measurement value (U43 ０ The ammonium analyzer configuration (10) according to claim 1 or 2, which shows the electrolyte volume (V34) for the difference between () and the actual calibration measurement value (U43).
5. The ammonium analyzer configuration (10) according to claim 1 or 2, wherein the measurement signal evaluation module (64) generates an ammonium concentration value based on the actual calibration solution measurement value (U43).
6. The ammonium analyzer configuration (10) according to claim 1 or 2, wherein the calibration solution (43) has an ammonium standard concentration of at least 5 mg / l.
7. A method for determining the actual volume (V34) of the electrolyte (34) in the ammonium analyzer configuration (10) according to claim 1 or 2, The steps include filling the sample chamber (22) with the calibration solution (43), Steps include generating calibration measurement values (U43), The steps include determining the electrolyte volume (V34) using the calibration / depletion graph (100), A method that includes this.