Ammonium analyzer device
By introducing an electronic controller and calibration/depletion chart into the ammonium analyzer, the electrolyte liquid volume is monitored in real time, solving the problems of measurement inaccuracy and frequent maintenance caused by electrolyte liquid evaporation, and achieving longer maintenance intervals and higher measurement accuracy.
Patent Information
- Application Number
- CN202480040560.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-07-06
- Filing Date
- 2024-06-25
- Publication Date
- 2026-02-13
AI Technical Summary
In existing ammonium analyzers, the continuous evaporation of the electrolyte liquid leads to a reduction in the volume of the electrolyte liquid, making it difficult to accurately measure the ammonium concentration. Furthermore, frequent maintenance intervals affect the measurement accuracy and equipment reliability.
An ammonium analyzer with an electronic controller is used. Through the interaction between the gas selective electrode unit and the calibration liquid, combined with the calibration/depletion chart, the electrolyte liquid volume is monitored in real time, extending the maintenance interval and maintaining measurement accuracy.
It enables reliable monitoring of electrolyte liquid volume and extends the maintenance interval from 90 days to 180 days, improving the reliability and accuracy of measurement and reducing the maintenance frequency.
Smart Images
Figure CN121532643A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an ammonium analyzer apparatus having a gas selective electrode unit having an electrolyte chamber housing filled with an electrolyte liquid, and to a method for determining the actual volume of the electrolyte liquid in the electrolyte chamber housing of the gas selective electrode unit. Background Technology
[0002] A typical ammonium analyzer setup includes a gas-selective electrode unit immersed in a sample chamber filled with a chamber liquid, which can be used as a sample liquid or a calibration liquid. The gas-selective electrode unit includes an electrolyte chamber housing filled with an electrolyte liquid and a measuring electrode element in direct contact with the electrolyte liquid. The electrolyte chamber housing contains a gas-sensitive membrane that separates the electrolyte liquid within the electrolyte chamber housing from the chamber liquid in the sample chamber. Typically, the gas-sensitive membrane is very thin and mechanically sensitive to pressure differences. Therefore, the electrolyte chamber housing has an exhaust port to ensure that the gas cushion above the electrolyte liquid is always at a constant atmospheric pressure.
[0003] However, the electrolyte liquid continuously evaporates through the venting opening, causing the volume of the electrolyte liquid inside the electrolyte chamber shell to continuously decrease.
[0004] To ensure constant conditions and allow for accurate measurement of ammonium concentration, the gas selective electrode unit is maintained at a constant temperature, for example, 45°C, which results in high evaporation of the electrolyte liquid.
[0005] Therefore, the ammonium analyzer unit must be calibrated regularly, for example, daily. Another consequence of the continuous evaporation of the electrolyte liquid is the eventual depletion of the electrolyte liquid. However, it is difficult to determine the electrolyte volume with a suitable sensor. In practice, the electrolyte chamber shell is refilled with electrolyte liquid at a constant maintenance interval of, for example, 90 days. Summary of the Invention
[0006] The purpose of this invention is to provide an ammonium analyzer device with a gas selective electrode unit and a method for providing high reliability and long maintenance intervals for the gas selective electrode unit.
[0007] According to the present invention, this objective is achieved by an ammonium analyzer apparatus having the features of claim 1 and a method having the features of method claim 7 for determining the actual volume of electrolyte liquid in the ammonium analyzer apparatus.
[0008] The ammonium analyzer device according to the present invention is equipped with an electronic controller and a measuring unit controlled by the electronic controller. The ammonium analyzer device can be laboratory equipment, but is preferably a process device with the longest possible maintenance intervals.
[0009] The measurement unit includes a sample chamber filled with a chamber liquid, which, in addition to a reagent liquid, is either sample liquid from a sample liquid point (e.g., from a water treatment plant basin) or filled with a calibration liquid for performing a calibration run.
[0010] The measuring unit also includes a gas selective electrode unit, which has an electrolyte chamber housing filled with a certain volume of electrolyte liquid. The electrolyte chamber housing is not completely fluid-tight, but is provided with a vent opening that ensures that the gas pressure of the gas cushion inside the electrolyte chamber housing is always at atmospheric pressure.
[0011] The gas-selective electrode unit includes a reference electrode element that is in direct contact with the electrolyte liquid. 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 liquid inside the electrolyte chamber housing from the chamber liquid in the sample chamber. The gas-sensitive membrane can be made of any suitable material, such as silicone resin. 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 liquid inside the electrolyte chamber housing. The gas selective electrode unit is always at least partially immersed in the chamber liquid.
[0014] Preferably, the sensing surface of the measuring electrode element is positioned very close to the gas-sensitive membrane, but not in direct contact with it, such that a thin layer of electrolyte liquid is disposed between the sensing surface of the measuring electrode element and the gas-sensitive membrane. More preferably, the thin electrolyte liquid layer has a volume of less than 1 ml.
[0015] The ammonium analyzer is equipped with a calibration liquid container, from which the calibration liquid is pumped into the sample chamber if, for example, a calibration run is initiated daily. Preferably, the calibration liquid 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 for generating differential measurements.
[0017] The electronic controller also includes a calibration module that generates calibration liquid measurements when the sample chamber is filled with calibration liquid. These calibration liquid measurements are important for the measurement signal evaluation module, which provides accurate measurements. For the measurement range of 0 to 1000 mg / L ammonium (NH4-N), the measurement signal evaluation module generates a voltage typically in the range of -300 mV to +300 mV as the measured value.
[0018] The electronic controller also includes an electrolyte depletion determination module, which comprises a depletion map memory storing calibration / depletion maps. The calibration / depletion map describes either the relationship between the calibration liquid measurement and the absolute actual volume of the electrolyte liquid in the gas selective electrode unit, or another relationship between the calibration liquid measurement and the actual volume of the electrolyte liquid in the gas selective electrode unit. Typically, the calibration liquid measurement increases as the volume of the electrolyte liquid in the electrolyte chamber housing decreases.
[0019] The electrolyte depletion determination module is signal-connected to the calibration module. During calibration operation, the electrolyte depletion determination module determines the actual volume of electrolyte liquid in the electrolyte chamber housing based on actual calibration measurements and the calibration / depletion chart. The electronic controller can process the determined actual volume of electrolyte liquid in different ways; for example, it can send a warning signal when the electrolyte liquid volume has reached its minimum, requiring refilling of the electrolyte chamber housing. Therefore, a fixed maintenance interval with an appropriate safety margin is not required, allowing the maintenance interval for refilling the electrolyte chamber housing to be extended from 90 days to 180 days in practice.
[0020] Preferably, the measuring unit is equipped with a heater and a temperature sensor, wherein the electronic controller includes a heating control module for controlling the temperature of the gas selective electrode unit at 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 measurements in an ammonium analyzer device are highly dependent on the temperatures of the electrolyte liquid, calibration liquid, and sample liquid. Therefore, a constant temperature for the measuring unit is necessary. As a side effect, the constant temperature of the measuring unit also leads to relatively constant evaporation of the electrolyte liquid in the electrolyte chamber housing, making other aging effects of the electrolyte liquid predictable. This results in the fact that a single calibration / depletion plot is sufficient to predict the electrolyte liquid volume based on calibration liquid measurements.
[0021] Preferably, the calibration / depletion graph illustrates the relationship between the electrolyte liquid volume in the electrolyte chamber housing and the difference between the initial calibration measurement and the actual calibration measurement. The initial calibration measurement is the first calibration measurement after a new or refilled gas selective electrode unit has been put into operation. More preferably, the initial calibration measurement can be the average of two or more consecutive initial calibration measurements.
[0022] Preferably, the calibration liquid has an ammonium standard concentration of at least 5 mg / L. The higher the ammonium standard concentration of the calibration liquid, the more reliable the determination of the actual volume of the electrolyte liquid.
[0023] Preferably, the measurement signal evaluation module generates an ammonium concentration value based on the actual measurement value of the calibration liquid.
[0024] Preferably, the ammonium analyzer device is provided with a reagent liquid tank containing a reagent liquid, a suitable volume of which is pumped into the sample chamber for reaction with the calibration liquid or sample liquid in the sample chamber. Attached Figure Description
[0025] An embodiment of the present invention is described with reference to the accompanying drawings, wherein:
[0026] Figure 1 An ammonium analyzer device with a gas-selective electrode unit and an electronic controller is schematically illustrated. The electronic controller includes a calibration module with an electrolyte depletion determination module, which includes a depletion map memory for storing calibration / depletion maps.
[0027] Figure 2 It is a calibration / depletion map stored in the depletion map memory. Detailed Implementation
[0028] Figure 1 A land-based ammonium analyzer arrangement 10 is schematically shown, which is typically a process analyzer. The ammonium analyzer arrangement 10 determines the ammonium concentration in a basin 12, which may be part of a water treatment plant. The basin 12 is filled with sample liquid 23, which can be pumped from the basin 12 to the measuring unit 20 by a liquid pump 50.
[0029] The ammonium analyzer device 10 is provided with a first calibration liquid container 42 having a first calibration liquid 43, and a second calibration liquid container 44 having a second calibration liquid 45. The first calibration liquid 43 in the first calibration liquid container 42 has an ammonium concentration of, for example, 10 mg / L, and the second calibration liquid 45 has a relatively low ammonium concentration of, for example, 1.0 mg / L.
[0030] The ammonium analyzer device 10 is equipped with two three-way valves 51 and 52 for selectively guiding the sample liquid 23, the first calibration liquid 43, or the second calibration liquid 45 through the liquid line between the water basin 12 and the sample chamber 22 of the measuring unit 20, and the liquid pump 50 to the sample inlet opening 24 of the sample chamber 22. The ammonium analyzer device 10 is also equipped with a waste liquid pump 53, which is used to pump the chamber liquid 22' in the sample chamber 22 to the wastewater tank 40 where wastewater 40' accumulates after the measurement operation.
[0031] The ammonium analyzer device 10 is equipped with a reagent tank 46, which contains a reagent liquid 47. The reagent liquid 47 can be pumped to the measuring unit 20 by a reagent pump 53. The reagent liquid 47 is preferably an alkaline solution, such as NaOH.
[0032] The measurement unit 20 essentially comprises a sample chamber 22 filled with a chamber liquid 22', which may be a sample liquid 23 in addition to the reagent liquid 47, or a calibration liquid 43, 45. It includes 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 at least partially immersed in the chamber liquid 22'.
[0033] The gas-selective electrode unit 30 includes an electrolyte chamber housing 31 made of glass or plastic, filled with a suitable electrolyte liquid 34 having an electrolyte level 34'. New or refilled gas-selective electrolyte units 30 include 11 ml of electrolyte liquid 34. The electrolyte liquid 34 may contain, for example, ammonium chloride at a concentration of 100 mmol / L, or, for a lower measurement range, ammonium chloride at a concentration of 2.0 mmol / L.
[0034] The electrolyte chamber housing 31 has an exhaust port 37 at its top, through which the electrolyte liquid 34 continuously evaporates. The electrolyte chamber housing 31 includes a gas-sensitive membrane 38 made of PTFE at its bottom, which separates the electrolyte liquid 34 inside the electrolyte chamber housing 31 from the chamber liquid 22' in the sample chamber 22.
[0035] The gas selective electrode unit 30 is also provided with a measuring electrode element 32, which is in direct contact with a thin electrolyte liquid layer 34'' of a small volume (e.g., 10 μl) of electrolyte liquid 34. The electrolyte liquid layer 34'' is disposed between the distal sensor surface of the measuring electrode element 32 and the gas sensitive membrane 38.
[0036] The measuring unit 20 is equipped with an electric heater 39 and a temperature sensor 59, both of which are electrically connected to the heating control module 70 for indirectly controlling the temperature of the gas selective electrode unit 30 and maintaining it at a constant temperature T of 45°C.
[0037] The electronic controller 60 includes a measurement signal evaluation module 64 electrically connected to the reference electrode element 28 and the gas selective electrode unit 30, for generating 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 volume 62, a depletion map memory 68 for storing the calibration / depletion map 100, and a monitor 69.
[0039] The calibration module 66 controls and initiates the calibration run, for example, once a day. When the calibration module 66 starts the calibration run, the first calibration liquid 43 is pumped into the sample chamber 22, and an appropriate volume of reagent liquid 47 is also pumped into the sample chamber 22. Then, the dissolved ammonium ions are converted into ammonia gas, which passes through the gas-sensitive membrane 38 and causes a potential change at the measuring electrode element 32.
[0040] A few minutes later, the measurement signal evaluation module 64 is instructed to generate a calibration liquid measurement value U43, which is the voltage value of the voltage difference between the potential at the reference electrode element 28 and the measurement electrode element 32.
[0041] Subsequently, the calibration run was initiated with the second calibration liquid 45, which resulted in a second calibration liquid measurement value U45. The two calibration liquid measurements, U43 and U45, were stored and used for subsequent ammonium measurements and determination over the next 24 hours.
[0042] The stored first calibration liquid measurement value U43 is also used by the electrolyte depletion determination module 62 to determine the volume V34 of the electrolyte liquid 34 in the electrolyte chamber housing 31. The electrolyte depletion determination module 62 determines the volume V34 of the electrolyte liquid 34 based on the data stored in the depletion map memory 68. Figure 2 The calibration / depletion diagram 100 shown in the figure determines the corresponding electrolyte liquid volume V34.
[0043] The actual electrolyte volume V34 is displayed on display 69. If the actual electrolyte volume V34 is about to be depleted, the electrolyte depletion determination module 62 causes display 69 to present a maintenance recommendation. The relevant depletion of electrolyte volume V34 reaches, for example, 3.0 ml.
Claims
1. An ammonium analyzer device (10) having an electronic controller (60) and a measuring unit (20), the measuring unit (20) comprising: A sample chamber (22) filled with a chamber liquid (22'), wherein the chamber liquid (22') is a sample liquid (23) or a calibration liquid (43). A gas selective electrode unit (30) having an electrolyte chamber housing (31) filled with electrolyte liquid (34). A reference electrode element (28) is in direct contact with the electrolyte liquid (34). A gas-sensitive membrane (38) separates the electrolyte liquid (34) from the chamber liquid (22'). Measuring electrode element (32), which is in direct contact with the electrolyte liquid (34), and Exhaust opening (37) at the electrolyte chamber housing (31). Among them, a calibration liquid container (42) with calibration liquid (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) to generate a measurement value (U). The electronic controller (60) includes a calibration module (66), which generates a calibration liquid measurement value (U43) when the sample chamber (22) is filled with calibration liquid (43). The electrolyte depletion determination module (62) is provided, which includes a depletion map memory (68) that stores calibration / depletion maps (100). The electrolyte depletion determination module (62) is signal-connected to the calibration module (66), and The electrolyte depletion determination module (62) determines the actual volume (V34) of the electrolyte liquid (34) based on the calibration measurement (U43) and the calibration / depletion map (100).
2. The ammonium analyzer device (10) according to claim 1, wherein, The measuring unit (20) is provided with a heater (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) at a constant set temperature T of at least 30°C.
3. The ammonium analyzer apparatus (10) according to any one of the preceding claims, wherein, The gas-sensitive membrane (38) is made of PTFE.
4. The ammonium analyzer apparatus (10) according to any one of the preceding claims, wherein, The calibration / depletion plot (100) shows the relationship between the electrolyte liquid volume (V34) and the difference between the initial calibration measurement (U430) and the actual calibration measurement (U43).
5. The ammonium analyzer apparatus (10) according to any one of the preceding claims, wherein, The measurement signal evaluation module (64) generates an ammonium concentration value based on the actual calibration liquid measurement value (U43).
6. The ammonium analyzer apparatus (10) according to any one of the preceding claims, wherein, The calibration liquid (43) has an ammonium standard concentration of at least 5 mg / L.
7. A method for determining the actual volume (V34) of an electrolyte liquid (34) in an ammonium analyzer apparatus (10) having the features of any one of the preceding claims, the method comprising the steps of: The sample chamber (22) is filled with calibration liquid (43). Generate calibration measurements (U43), and The electrolyte liquid volume (V34) was determined by the calibration / depletion plot (100).