An active temperature-controlled dehumidification and cooling system for an ultra-low background liquid scintillation spectrometer

Abstract

This invention provides an active temperature-controlled dehumidification and refrigeration system for an ultra-low background liquid scintillation spectrometer, comprising a refrigeration module, a cold storage hood, an airflow circulation module, and an intelligent control module. The refrigeration module includes a Peltier refrigeration module, with the cold storage hood sealingly enclosing the cold end of the Peltier refrigeration module. A cold air outlet is located at the top of the cold storage hood. A variable frequency drive fan from the airflow circulation module is installed inside the cold air outlet, and an air duct connects the cold air outlet at the top of the cold storage hood to the lead chamber of the ultra-low background liquid scintillation spectrometer. The intelligent control module includes a controller, a drive circuit, and sensors for monitoring environmental parameters within the lead chamber. The sensors are connected to the controller, which is connected to the Peltier refrigeration module and the variable frequency drive fan via the drive circuit. This system provides a highly stable, low-humidity, low-temperature operating environment for the lead chamber of the ultra-low background liquid scintillation spectrometer.

Description

Technical Field

[0001] This utility model relates to the field of ultra-low background liquid scintillation spectrometer technology, and in particular to an active temperature control dehumidification and cooling system for an ultra-low background liquid scintillation spectrometer. Background Technology

[0002] Ultra-low background liquid scintillation spectrometers are crucial instruments for measuring extremely low-level radionuclides (such as tritium and carbon-14), and their detection sensitivity and accuracy heavily depend on the detector's background noise level. The photomultiplier tube (PMT), as the core sensor, exhibits an exponential relationship between its dark current and temperature; the dark current approximately doubles for every 10°C increase in temperature. Furthermore, temperature fluctuations affect the luminescence efficiency of the scintillation fluid, introducing counting errors. Therefore, it is necessary to provide a cooling system that maintains the stable low-temperature and low-humidity environment required for the lead chamber of the ultra-low background liquid scintillation spectrometer, providing a highly stable, low-humidity low-temperature operating environment for the PMT and sample chamber within the lead chamber. Summary of the Invention

[0003] This invention provides an active temperature control and dehumidification cooling system for an ultra-low background liquid scintillation spectrometer. This system can provide a highly stable, low-humidity, low-temperature working environment for the lead chamber of the ultra-low background liquid scintillation spectrometer.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0005] An active temperature-controlled dehumidification and cooling system for an ultra-low background liquid scintillation spectrometer includes:

[0006] A refrigeration module, which includes at least one Peltier refrigeration module;

[0007] The cold storage cover is a sealed enclosure for the cold end of the Peltier refrigeration module, and a cold air outlet is provided at the top of the cold storage cover.

[0008] The airflow circulation module includes a flow guide variable frequency fan and an air supply duct. The flow guide variable frequency fan is installed in the cold air outlet at the top of the cold storage cover, and the air supply duct connects the cold air outlet at the top of the cold storage cover to the lead chamber of the ultra-low background liquid scintillation spectrometer.

[0009] The intelligent control module includes a controller, a drive circuit, and sensors for monitoring indoor environmental parameters of lead-containing rooms. The sensors are connected to the controller, which is connected to the Peltier cooling module and the variable frequency fan via the drive circuit. Based on the received sensor feedback signals, the controller controls the current of the Peltier cooling module via the drive circuit and simultaneously controls the speed of the variable frequency fan.

[0010] The Peltier cooling module includes a thermoelectric cooler, a cold-end heat sink and a cold-end cooling fan installed on the cold end of the thermoelectric cooler, and a hot-end heat sink and a hot-end cooling fan installed on the hot end of the thermoelectric cooler. The cold end of the thermoelectric cooler, the cold-end heat sink and the cold-end cooling fan are all located inside the cold storage cover.

[0011] The bottom of the cold storage cover is a sloping structure with a condensate outlet at the lowest point. The condensate outlet is connected to an external conduit to collect and drain the condensate.

[0012] The cold storage cover is made of a polymer material with low thermal conductivity.

[0013] The outer surface of the cold storage cover is covered with an insulation layer.

[0014] The cold storage cover is equipped with air inlets for balancing internal and external air pressure.

[0015] The controller is a PID controller.

[0016] The controller drive circuit is an H-bridge drive circuit.

[0017] The variable frequency fan is a brushless DC variable frequency fan.

[0018] The sensor includes at least one temperature sensor and at least one humidity sensor.

[0019] Compared with the prior art, the beneficial effects of this utility model are: (1) The active temperature control and dehumidification cooling system of the ultra-low background liquid scintillation spectrometer provided by this utility model is cooled by the Peltier cooling module, and then the dry cold air in the storage hood is blown into the lead chamber through the air supply pipe by the guide variable frequency fan. At the same time, the PID controller controls the current of the Peltier cooling module and the speed of the guide variable frequency fan through the H-bridge drive circuit according to the temperature and humidity data monitored by the sensor. The temperature and humidity in the lead chamber are adjusted by the Peltier cooling module and the guide variable frequency fan together, providing a high-stability, low-humidity low-temperature working environment for the lead chamber of the ultra-low background liquid scintillation spectrometer, ensuring that the ultra-low background liquid scintillation spectrometer can obtain stable and reliable low background performance under various environmental conditions. (2) In this utility model, the storage hood adopts a slope design and is equipped with a condensate outlet. Combined with the airflow circulation of the guide variable frequency fan with controllable air volume, the active discharge and collection of condensate is realized. Attached Figure Description

[0020] Figure 1 A schematic diagram of the active temperature control dehumidification and refrigeration system for the ultra-low background liquid scintillation spectrometer provided by this utility model;

[0021] Figure 2 A cross-sectional schematic diagram of the active temperature control dehumidification and cooling system for the ultra-low background liquid scintillation spectrometer provided by this utility model.

[0022] Figure 3 This is a schematic diagram of the refrigeration module in this utility model;

[0023] In the diagram, 1-cooling module, 11-semiconductor cooling chip, 12-cold end heat sink, 13-cold end cooling fan, 14-hot end heat sink, 15-hot end cooling fan, 2-cold storage cover, 31-flow guide variable frequency fan, 32-air supply duct, 4-lead chamber, 5-connecting plate, 6-insulation layer, 7-condensate outlet. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] The active temperature control, dehumidification, and cooling system for the ultra-low background liquid scintillation spectrometer provided in this embodiment is as follows: Figure 1 and Figure 2 As shown, it includes a refrigeration module 1, a cold storage cover 2, an airflow circulation module, and an intelligent control module.

[0026] The cooling module includes at least one Peltier cooling module, which includes a thermoelectric cooler 11, a cold-end heat sink 12 and a cold-end cooling fan 13 mounted on the cold end of the thermoelectric cooler, and a hot-end heat sink 14 and a hot-end cooling fan 15 mounted on the hot end of the thermoelectric cooler. Figure 3 As shown. The installation of the thermoelectric cooler, its hot-end heat sink, and its hot-end cooling fan are all existing mature technologies and will not be described in detail here. In this embodiment, the installation of the cold-end heat sink and the cold-end cooling fan is the same as that of the hot-end heat sink and the hot-end cooling fan, the difference being the installation position. The function of the cold-end heat sink and the cold-end cooling fan is to accelerate the diffusion of air at the cold end of the thermoelectric cooler and improve the uniformity of the cold air in the cold storage cover.

[0027] The cold storage cover is a sealed enclosure over the cold end of the Peltier cooling module, specifically encapsulating the cold end of the thermoelectric cooler, its heat sink, and its cooling fan, thereby sealing in the cold air generated by the cold end of the thermoelectric cooler. Specifically, a connecting plate 5 is seamed and fixed around the thermoelectric cooler, and the cold storage cover is placed over the cold end of the thermoelectric cooler and fixed against the connecting plate. Furthermore, the cold storage cover is made of a polymer material with low thermal conductivity, such as ABS resin. An insulation layer 6 is wrapped around the outer surface of the cold storage cover for effective heat insulation. In this embodiment, the bottom of the cold storage cover has a sloping structure with a condensate outlet 7 at the lowest point. The condensate outlet is connected to an external conduit. When the system is running, the low temperature at the cold end is transferred to the inner wall of the cold storage cover, where water vapor condenses. The condensate flows down the bottom slope to the condensate outlet and is then discharged through the external conduit. Note that the insulation layer should not cover the condensate outlet.

[0028] The top of the cold storage hood is equipped with a cold air outlet. The airflow circulation module includes a variable frequency fan 31 and an air supply duct 32. The air supply duct connects the cold air outlet at the top of the cold storage hood to the lead chamber 4 of the ultra-low background liquid scintillation spectrometer. The variable frequency fan is installed inside the cold air outlet at the top of the cold storage hood, blowing dry, cold air from inside the cold storage hood through the air supply duct to the photomultiplier tube and sample chamber inside the lead chamber. Specifically, multiple air supply ducts are provided, with a split adapter connected to the cold air outlet. One end of each air supply duct is connected to the split adapter, and the other end is distributed and connected to different positions in the lead chamber, uniformly delivering cold air into the lead chamber. Specifically, the cold storage hood is equipped with an air inlet (not shown in the figure) for balancing the internal and external air pressure. The air inlet connects the inside and outside of the cold storage hood, and works in conjunction with the variable frequency fan to create stable convection within the cold storage hood.

[0029] The intelligent control module includes a controller, a drive circuit, and sensors for monitoring environmental parameters within the lead chamber. The sensors are connected to the controller, which in turn connects to a Peltier cooling module and a variable frequency drive fan via the drive circuit. Based on received sensor feedback signals, the controller controls the current of the Peltier cooling module and simultaneously controls the speed of the variable frequency drive fan. Specifically, the sensors include at least one temperature sensor and at least one humidity sensor, which monitor the real-time temperature and humidity within the lead chamber. The controller is a PID controller. The drive circuit is an H-bridge drive circuit. The variable frequency drive fan is a brushless DC variable frequency fan, whose airflow can be steplessly adjusted under controller commands. The controller's control of the current magnitude and direction of the Peltier cooling module and the airflow adjustment of the variable frequency drive fan via the H-bridge drive circuit are existing technologies and will not be described in detail here.

[0030] The working method of the active temperature control dehumidification and cooling system of the ultra-low background liquid scintillation spectrometer provided in this embodiment includes the following steps: (1) Pre-setting the target temperature and target humidity in the lead chamber;

[0031] (2) Temperature and humidity sensors collect the actual temperature and humidity inside the lead chamber in real time and feed them back to the PID controller;

[0032] (3) Based on the difference between the target temperature and the actual temperature, the PID controller outputs a first control signal to adjust the direction and magnitude of the current in the Peltier thermoelectric refrigeration module to achieve refrigeration or heating (anti-freezing); simultaneously, based on the temperature difference and / or the actual humidity, the PID controller outputs a second control signal to adjust the speed of the variable frequency fan, thereby controlling the air volume and flow rate of the cold air supplied to the lead chamber; when the temperature is too high or the humidity is too high, the fan speed is increased to enhance the refrigeration and dehumidification effect; when approaching the target value, the speed is reduced to save energy and reduce temperature fluctuations. The condensate generated during refrigeration is discharged through the condensate outlet under the guidance of the slope at the bottom of the cold storage cover, realizing active temperature control, dehumidification, and refrigeration in the lead chamber.

[0033] System Operation and Performance Testing: The active temperature control and dehumidification cooling system of the ultra-low background liquid scintillation spectrometer provided in this embodiment was tested under normal environmental conditions (ambient temperature 25℃, relative humidity 60%RH) and extreme environmental conditions (ambient temperature 30℃, relative humidity 80%RH). The target temperature of the lead chamber was set at 16℃, and the target humidity at 45%RH. Tests showed that under normal environmental conditions, the temperature remained stable at 15.8-16.2℃ (fluctuation ±0.2℃), and the humidity remained stable at 41-44%RH; under extreme environmental conditions, the temperature remained stable at 15.7-16.3℃ (fluctuation ±0.3℃), and the humidity fluctuated within a range of 42-45%RH. Simultaneous detection of the PMT background count rate showed an average fluctuation of 9% cpm, far below the industry standard of 15% cpm. These tests demonstrate that the system can stably maintain the set temperature and humidity of the lead chamber under different environmental conditions, meeting the operational requirements of the ultra-low background liquid scintillation spectrometer.

Claims

1. An active temperature-controlled dehumidification and refrigeration system for an ultra-low background liquid scintillation spectrometer, characterized in that... include: A refrigeration module, which includes at least one Peltier refrigeration module; The cold storage cover is a sealed enclosure for the cold end of the Peltier refrigeration module, and a cold air outlet is provided at the top of the cold storage cover. The airflow circulation module includes a flow guide variable frequency fan and an air supply duct. The flow guide variable frequency fan is installed in the cold air outlet at the top of the cold storage cover, and the air supply duct connects the cold air outlet at the top of the cold storage cover to the lead chamber of the ultra-low background liquid scintillation spectrometer. The intelligent control module includes a controller, a drive circuit, and sensors for monitoring indoor environmental parameters of lead-containing rooms. The sensors are connected to the controller, which is connected to the Peltier cooling module and the variable frequency fan via the drive circuit. Based on the received sensor feedback signals, the controller controls the current of the Peltier cooling module via the drive circuit and simultaneously controls the speed of the variable frequency fan.

2. The active temperature control, dehumidification, and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The Peltier cooling module includes a thermoelectric cooler, a cold-end heat sink and a cold-end cooling fan installed on the cold end of the thermoelectric cooler, and a hot-end heat sink and a hot-end cooling fan installed on the hot end of the thermoelectric cooler. The cold end of the thermoelectric cooler, the cold-end heat sink and the cold-end cooling fan are all located inside the cold storage cover.

3. The active temperature control, dehumidification, and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The bottom of the cold storage cover is a sloping structure with a condensate outlet at the lowest point. The condensate outlet is connected to an external conduit to collect and drain the condensate.

4. The active temperature-controlled dehumidification and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The cold storage cover is made of a polymer material with low thermal conductivity.

5. The active temperature control, dehumidification, and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The outer surface of the cold storage cover is covered with an insulation layer.

6. The active temperature-controlled dehumidification and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The cold storage cover is equipped with air inlets for balancing internal and external air pressure.

7. The active temperature-controlled dehumidification and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The controller is a PID controller.

8. The active temperature control, dehumidification, and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The controller drive circuit is an H-bridge drive circuit.

9. The active temperature control, dehumidification, and refrigeration system for an ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The variable frequency fan is a brushless DC variable frequency fan.

10. The active temperature-controlled dehumidification and refrigeration system for the ultra-low background liquid scintillation spectrometer according to claim 1, characterized in that: The sensor includes at least one temperature sensor and at least one humidity sensor.

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