Calibration device for flue gas hygrometer

Abstract

The utility model relates to a calibration device for a flue gas hygrometer. The calibration device comprises a gas supply unit, a dry gas branch, a wet gas branch, a mixing unit and a calibration unit, the air supply unit comprises an air source assembly, a dryer, a pressure regulating filter, an air source electromagnetic valve and a three-way joint which are connected in sequence; one end of the moisture branch is connected to a first outlet of the three-way connector, the other end of the moisture branch is connected to a moisture generator in the mixing unit, and the moisture branch comprises a moisture input electromagnetic valve and a moisture flow meter; one end of the dry gas branch is connected to a second outlet of the three-way joint, and the other end is connected to a constant-temperature closed tank in the mixing unit; the dry gas branch comprises a dry gas input electromagnetic valve and a dry gas flowmeter; the calibration unit comprises a calibration cavity, the constant-temperature mixing tank is connected with the calibration cavity, and the calibration cavity is provided with an interface used for being connected with a humidity sensor. The device has the advantages of being wide in humidity generation range, fast in humidity conversion, high in accuracy, wide in calibration range and good in stability.

Description

Technical Field

[0001] The utility model relates to the technical field of humidity meter calibration, in particular to a flue gas humidity meter calibration device. Background Art

[0002] A flue gas humidity meter is an instrument that can monitor the water vapor content in flue gas online. It plays a vital role in the continuous emission monitoring system (CEMS) for stationary pollution sources. A flue gas humidity meter directly measures flue gas humidity, typically expressed as relative humidity or absolute humidity. This instrument monitors changes in flue gas humidity in real time, enabling timely detection of anomalies and adjustments to production parameters to ensure stable and safe production. A flue gas humidity meter can also be used in conjunction with other flue gas analyzers to measure other pollutants in the flue gas, such as sulfur dioxide, nitrogen oxides, and carbon monoxide.

[0003] Flue gas humidity meters require calibration to ensure their accuracy and reliability. Calibration is a crucial process that involves testing the instrument's accuracy under specified conditions using standard metrology equipment to ensure compliance with measurement standards. Calibration primarily determines the input-output relationship of the online flue gas monitoring system, assigning instrument graduations; determines the instrument's static characteristic indicators; and eliminates systematic errors, improving the instrument's accuracy to meet analytical requirements. Furthermore, calibration helps ensure the reliability and accuracy of measurement results.

[0004] Existing flue gas humidity meter calibration equipment has specific requirements for air humidity: dry air is required for automatic zero point calibration. However, the air in southern China, especially in spring or the rainy season, is relatively humid. This can cause zero point drift during automatic zero point calibration, affecting calibration accuracy. Lack of a clear humidity alarm device: In an online flue gas monitoring system, if a humidity alarm is not installed, it is difficult to detect whether there is excessive liquid water in the system sampling line. This can cause the sampling pump to malfunction and other components such as the gas analyzer to gradually corrode, greatly affecting the scientific nature and accuracy of the online flue gas monitoring system. The calibration temperature and humidity are limited and cannot be used for calibrating high-temperature and high-humidity dew point meters. The required humidity alternating test is slow to respond and the humidity drops very slowly. The invention patent with application publication number CN105737877A relates to a temperature and humidity sensor calibration device that uses an air pump to pump external air into a calibration chamber, where it mixes with the liquid in the chamber to form a mixed gas with a preset humidity value. Utility Model Content

[0005] The purpose of the utility model is to provide a calibration device for a flue gas humidity meter.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A flue gas humidity meter calibration device comprises an air supply unit, a dry gas branch, a wet gas branch, a mixing unit and a calibration unit; the air supply unit comprises an air source component, a dryer, a pressure regulating filter, an air source solenoid valve and a three-way joint connected in sequence; one end of the wet gas branch is connected to the first outlet of the three-way joint, and the other end is connected to the wet gas generator in the mixing unit, and the wet gas branch comprises a wet gas input solenoid valve and a wet gas flow meter; one end of the dry gas branch is connected to the second outlet of the three-way joint, and the other end is connected to the constant temperature mixing tank in the mixing unit; the dry gas branch comprises a dry gas input solenoid valve and a dry gas flow meter; the calibration unit comprises a calibration chamber, the constant temperature mixing tank is connected to the calibration chamber, and the calibration chamber is provided with an interface for connecting a humidity sensor.

[0008] Furthermore, the air source assembly includes an air intake filter and an air compressor.

[0009] Furthermore, a cold dryer is connected between the air compressor and the dryer.

[0010] Furthermore, a stop valve is provided between the cold dryer and the dryer.

[0011] Furthermore, a buffer tank is provided on the wet gas branch line, and the buffer tank is located between the wet gas flow meter and the wet gas generator.

[0012] Furthermore, the moisture generator includes a saturation chamber, a drain valve is provided at the bottom of the saturation chamber, and the buffer tank is connected to an air inlet valve for drainage.

[0013] Furthermore, the moisture generator includes a saturation chamber, the pipe of the moisture branch extends into the saturation chamber, the saturation chamber is connected to a water inlet branch, a liquid level sensor, a temperature sensor, and a pressure sensor, a heater and a foamer are provided in the saturation chamber, and the water inlet branch includes a water inlet solenoid valve.

[0014] Furthermore, the moisture generator includes a saturation chamber, which is connected to a constant temperature tank via a heat preservation pipe, and the constant temperature tank is connected to the calibration chamber via a heat tracing pipe.

[0015] Furthermore, a circulating fan is provided in the calibration chamber.

[0016] Furthermore, a drain outlet is provided at the bottom of the calibration chamber.

[0017] Beneficial effects of the utility model:

[0018] (1) The utility model is a calibration device for a flue gas humidity meter, in which the humidity generating part can adopt either the split flow method or the mixed flow method, integrating the advantages of the two methods and can be selected according to specific circumstances. It has high accuracy, the advantages of a wide humidity generating range and fast humidity conversion, a wide calibration range, and good stability.

[0019] (2) Using a cold dryer and an electric dryer to dry the compressed air entering the calibration device can calibrate instruments with lower dew points.

[0020] (3) A stop valve is installed between the cold dryer and the dryer to control the shutoff of the front-stage gas, which facilitates the debugging and maintenance of the subsequent equipment.

[0021] (4) A buffer tank is designed on the wet gas branch line. The buffer tank is located between the wet gas flow meter and the wet gas generator. The buffer tank can prevent the water in the saturation chamber from flowing back after the gas supply stops, and prevent the wet gas flow meter from being damaged by water ingress.

[0022] (5) The liquid level sensor is used to monitor and detect the water level in the saturation chamber, and in conjunction with the liquid level switch, it can prevent the liquid level sensor from malfunctioning and causing the water level in the saturation chamber to overflow or dry-burn when it is too low, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a principle diagram of a calibration device for a flue gas humidity meter of the utility model.

[0024] 1. Inlet filter; 2. Air compressor; 3. Air source filter; 4. Cold dryer; 5. Stop valve; 6. Dryer; 7. Pressure regulating filter; 8. Air source solenoid valve; 9. Tee connector; 10. Dry gas input solenoid valve; 11. Dry gas flowmeter; 12. Wet gas input solenoid valve; 13. Wet gas mass flowmeter; 14. Buffer tank; 15. Inlet valve; 16. Water storage tank; 17. Water pump; 18. Water inlet solenoid valve; 19. Liquid level sensor; 20. Temperature sensor; 21. Liquid level switch; 22. Pressure sensor; 23. Drain valve; 24. Saturation chamber; 25. Heater; 26. Foamer; 27. Insulation pipe; 28. Constant temperature mixing tank; 29. ​​Heating pipe; 30. Humidity sensor; 31. Temperature control switch; 32. Circulation fan; 33. Drain outlet. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0026] Embodiments of the present utility model:

[0027] like Figure 1The device, shown in Figure 1, is a flue gas humidity meter calibration device. It includes a gas supply unit, a dry gas branch, a wet gas branch, a mixing unit, and a calibration unit. The gas supply unit provides gas at a certain pressure. The dry gas branch provides dry gas. The wet gas branch transports the diverted dry gas to the mixing unit for saturation with water vapor and then mixes it with the gas in the dry gas branch. The mixed gas, which has a certain humidity, enters the calibration unit for calibration. The detailed structure and connection relationship of each unit are described below.

[0028] The air supply unit includes an air source assembly, a cold dryer 4, a dryer 6, a pressure regulating filter 7, an air source solenoid valve 8, and a three-way connector 9, all connected in sequence. The air source assembly includes an air intake filter 1, an air compressor 2, and an air source filter 3. Both filters filter impurities and can be used with existing filters. A quiet, high-flow air compressor 2 is used to ensure adequate air supply and low noise. The air source solenoid valve 8 controls the flow of gas, and the three-way connector 9 diverts the flow of gas.

[0029] Refrigerated dryer 4 dries the compressed air. The dried air from refrigerated dryer 4 may contain some water droplets, which is further dried by dryer 6, a conventional electrically controlled dual-tower dryer. The combination of refrigerated dryer 4 and the electrically controlled dual-tower dryer dries the compressed air entering the device, enabling the device to calibrate instruments with even lower dew points.

[0030] The dried gas passes through the pressure regulating filter 7 and the gas source solenoid valve 8, and is then divided into two paths through the three-way connector 9. The pressure regulating filter 7 not only provides sufficient compressed gas, but also filters impurities and reduces pressure to extend the life of subsequent components such as the solenoid valve and mass flow meter.

[0031] A stop valve 5 is provided between the cold dryer 4 and the dryer 6 to shut off the front-stage gas and facilitate the commissioning and maintenance of the back-stage equipment.

[0032] One end of the wet gas branch is connected to the first outlet of the three-way joint 9, and the other end is connected to the wet gas generator in the mixing unit. The wet gas branch includes a wet gas input solenoid valve 12 and a wet gas flow meter 13. The wet gas flow meter 13 is a wet gas mass flow meter.

[0033] One end of the dry gas branch is connected to the second outlet of the three-way joint 9, and the other end is connected to the constant temperature tank in the mixing unit; the dry gas branch includes a dry gas input solenoid valve 10 and a dry gas flowmeter 11, and the dry gas flowmeter 11 is a dry gas mass flowmeter.

[0034] The moisture generator includes a saturation chamber 24, into which one end of the moisture branch pipe extends. A buffer tank 14 is installed on the moisture branch, located between the moisture flowmeter 13 and the moisture generator. This buffer tank 14 prevents water from flowing back into the saturation chamber 24 after the gas supply stops, preventing damage to the moisture flowmeter 13 caused by water ingress.

[0035] The saturation chamber 24 is connected to a water inlet branch, a liquid level sensor 19, a temperature sensor 20, and a pressure sensor 22. The water inlet branch includes a water tank 16, a water pump 17, and a water inlet solenoid valve 18. Based on the water level in the saturation chamber 24 (based on data from the liquid level sensor 19), water is automatically added to the saturation chamber 24. The liquid level sensor 19, temperature sensor 20, pressure sensor 22, heater 25, bubbler 26, water pump 17, and water inlet solenoid valve 18 are all connected to a control system.

[0036] The liquid level sensor 19, temperature sensor 20, and pressure sensor 22 are used to monitor the liquid level, temperature, and pressure within the saturation chamber 24, respectively. A liquid level switch 21 is also installed within the saturation chamber 24 to assist in controlling the highest and lowest points of the liquid level. This prevents malfunction of the liquid level sensor 19, which could cause the water level in the saturation chamber 24 to overflow, or prevent the water level from exceeding the limit and causing the heater 25 to dry out. The liquid level switch 21 is also connected to the control system. When triggered, it directly cuts off the power supply to the water pump 17 or the heater 25.

[0037] The pressure in the saturation chamber 24 can be monitored by the pressure sensor 22 to prevent inaccurate data caused by the saturation chamber 24 being pressurized.

[0038] A heater 25 is provided within the saturation chamber 24 to heat the water within the chamber to produce saturated water vapor at different temperatures. The heater 25 can be an electric heating rod. A foamer 26 is also provided to allow the dry gas and water to fully fuse to produce saturated water vapor.

[0039] A drain valve 23 is also provided at the bottom of the saturation chamber 24, and an air intake valve 15 for drainage is connected to the buffer tank 14. When the device is not used for a long time, air is taken in through the air intake valve 15, and the drain valve 23 is opened at the same time to drain the water in the saturation chamber 24.

[0040] The calibration unit includes a calibration chamber connected to a thermostatic mixing tank 28. The saturation chamber 24 is connected to a thermostatic merging tank via an insulation pipe 27, which in turn is connected to the calibration chamber via a heat tracing pipe 29. The insulation pipe 27 and heat tracing pipe 29 prevent condensation during gas delivery, ensuring data accuracy.

[0041] The calibration chamber is provided with an interface for connecting the humidity sensor 30. This embodiment is mainly used for calibration of the flue gas humidity meter. Therefore, the interface is connected to the humidity sensor 30 and can also be connected to a temperature and humidity sensor.

[0042] A circulating fan 32 is provided in the calibration chamber to disperse the gas in the calibration chamber quickly and evenly.

[0043] A drain port 33 is provided at the bottom of the calibration chamber to drain the dew in the calibration chamber to prevent it from affecting the accuracy of the data.

[0044] A temperature control switch 31 is provided in the calibration chamber. When a temperature and humidity sensor is connected, it can prevent the calibration chamber temperature from being too high and causing damage to components when the temperature and humidity sensor fails.

[0045] The working principle of the utility model flue gas humidity meter calibration device:

[0046] The air flows through intake filter 1, air compressor 2, and air source filter 3 to cold dryer 4, where the compressed air is dried. Dryer 6 further dries the air, which is then filtered and reduced in pressure by pressure-regulating filter 7. After passing through gas source solenoid valve 8 and tee connector 9, the air is split into two paths. One path provides dry gas with a controllable flow rate to the subsequent stage via dry gas input solenoid valve 10 and dry gas mass flowmeter 11. The other path provides wet gas with a controllable flow rate to the subsequent stage via wet gas input solenoid valve 12, wet gas mass flowmeter 13, buffer tank 14, saturation chamber 24, and insulation pipe 27. The wet gas is mixed with the dry gas in constant temperature mixing tank 28 and then enters the calibration chamber through heating pipe 29. A liquid level sensor 19 monitors the water level for automatic water replenishment, and a liquid level switch assists in controlling the maximum and minimum liquid levels. To replenish water, open the water inlet solenoid valve 18, and pump 17 pumps water into the saturation chamber 24.

[0047] The utility model is a calibration device for a flue gas humidity meter, in which the humidity generating part can adopt either the split flow method or the mixed flow method, integrating the advantages of the two methods and can be selected according to specific circumstances. It has high accuracy, the advantages of a wide humidity generating range and fast humidity conversion, a wide calibration range and good stability.

Claims

1. A flue gas humidity meter calibration device, characterized by: Including gas supply unit, dry gas branch, wet gas branch, mixing unit and calibration unit; The air supply unit includes an air source component, a dryer, a pressure regulating filter, an air source solenoid valve, and a three-way connector connected in sequence; One end of the wet gas branch is connected to the first outlet of the tee joint, and the other end is connected to the wet gas generator in the mixing unit. The wet gas branch includes a wet gas input solenoid valve and a wet gas flow meter; One end of the dry gas branch is connected to the second outlet of the three-way joint, and the other end is connected to the constant temperature tank in the mixing unit; the dry gas branch includes a dry gas input solenoid valve and a dry gas flow meter; The calibration unit comprises a calibration cavity, the constant temperature mixing tank is connected to the calibration cavity, and the calibration cavity is provided with an interface for connecting the humidity sensor.

2. The flue gas humidity meter calibration device according to claim 1, characterized in that: The air source component includes an air intake filter and an air compressor.

3. The flue gas humidity meter calibration device according to claim 2, characterized in that: A cold dryer is connected between the air compressor and the dryer.

4. The flue gas humidity meter calibration device according to claim 3, characterized in that: A stop valve is provided between the cold dryer and the dryer.

5. The flue gas humidity meter calibration device according to claim 1, characterized in that: A buffer tank is provided on the wet gas branch line, and the buffer tank is located between the wet gas flow meter and the wet gas generator.

6. The flue gas humidity meter calibration device according to claim 5, characterized in that: The moisture generator comprises a saturation chamber, a drainage valve is provided at the bottom of the saturation chamber, and the buffer tank is connected to an air inlet valve used for drainage.

7. The flue gas humidity meter calibration device according to claim 1, characterized in that: The moisture generator includes a saturation chamber, the pipeline of the moisture branch extends into the saturation chamber, the saturation chamber is connected to a water inlet branch, a liquid level sensor, a temperature sensor, and a pressure sensor, a heater and a foamer are provided in the saturation chamber, and the water inlet branch includes a water inlet solenoid valve.

8. The flue gas humidity meter calibration device according to claim 1, characterized in that: The moisture generator comprises a saturation chamber, which is connected to a constant temperature tank via a heat preservation pipe, and the constant temperature tank is connected to the calibration chamber via a heat tracing pipe.

9. The flue gas humidity meter calibration device according to claim 1, characterized in that: A circulating fan is provided in the calibration chamber.

10. The flue gas humidity meter calibration device according to claim 1, characterized in that: A drain outlet is provided at the bottom of the calibration chamber.

Images