Device for testing crystallization point of nitric acid liquid

Abstract

The utility model discloses a nitric acid liquid devitrification point testing device, including nitric acid liquid tank, test subassembly and thermoregulation system, the test subassembly includes heat preservation outer casing and heat conduction inner casing, heat conduction inner casing is installed in the heat preservation outer casing, the outer wall of heat conduction inner casing and the inside of heat preservation outer casing form thermoregulation cavity, the thermoregulation cavity is equipped with the thermoregulation system. The temperature adjusting cavity is filled with a temperature control medium, a temperature control medium inlet is formed in the lower portion of the heat preservation shell, a temperature control medium outlet is formed in the side, away from the temperature control medium inlet, of the upper portion of the heat preservation shell, and the temperature control medium outlet is connected with an inlet of the temperature adjusting system. And the temperature control medium inlet is connected with the outlet of the temperature adjusting system. According to the utility model, accurate measurement of the crystallization point of the nitric acid liquid is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of crystallization point testing equipment, in particular to a crystallization point testing device for nitric acid liquid. Background Art

[0002] The crystallization point of ammonium nitrate aqueous solution is a very important control parameter in the production process of industrial explosives, which directly affects the performance and storage period of the explosives. In the current production process, it is mainly measured by manual stirring and cooling with a thermometer and by visual observation of crystal precipitation by staff. This method has variable test conditions and relies on the experience and judgment of the staff, resulting in large errors in the measured crystallization point. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one purpose of the present invention is to provide a device for testing the crystallization point of nitric acid liquid, which can achieve accurate measurement of the crystallization point of nitric acid liquid.

[0004] According to the utility model, a nitric acid liquid crystallization point test device is proposed, which includes a nitric acid liquid tank, a test component and a temperature control system. The test component includes a heat-insulating outer shell and a heat-conducting inner shell. The heat-conducting inner shell is installed inside the heat-insulating outer shell. The outer wall of the heat-conducting inner shell and the interior of the heat-insulating outer shell form a temperature control cavity. The temperature control cavity is filled with a temperature control medium. The lower part of the heat-insulating outer shell is provided with a temperature control medium inlet. The upper part of the heat-insulating outer shell is provided with a temperature control medium outlet on a side away from the temperature control medium inlet. The temperature control medium outlet is connected to the inlet of the temperature control system. The temperature control medium inlet is connected to the outlet of the temperature control system, the heat-conducting inner shell is provided with a test solution outlet and a test solution inlet, the outlet of the nitric acid liquid tank is connected to the test solution inlet through a solution delivery pump, the reflux port of the nitric acid liquid tank is connected to the test solution outlet through a solution emptying pump, stirring paddles are installed on both sides of the heat-conducting inner shell, a photoelectric transmitter is installed on one side of the middle of the heat-conducting inner shell, a photoelectric receiver is installed on the other side of the middle of the heat-conducting inner shell at the position corresponding to the photoelectric transmitter, and a third temperature sensor is also installed inside the heat-conducting inner shell.

[0005] Preferably, the temperature control system includes a heating component and a cooling component, the temperature control medium inlet is connected to the inlet of the heating component and the inlet of the cooling component respectively through a circulation pump and a first temperature sensor in sequence, the temperature control medium outlet is connected to the outlet of the heating component and the outlet of the cooling component respectively through a second temperature sensor, and the inlet and outlet of the heating component and the inlet and outlet of the cooling component are both installed with solenoid valves.

[0006] Preferably, the outlet of the nitric acid liquid tank is connected to the solution delivery pump through a first pipe fitting, and the first pipe fitting includes a first pipe fitting port 1, a first pipe fitting port 2, a first pipe fitting port 3 and a first pipe fitting port 4, one end of the first pipe fitting port 1, one end of the first pipe fitting port 3 and one end of the first pipe fitting port 4 are respectively connected to one end of the first pipe fitting port 2, the other end of the first pipe fitting port 1 is connected to the outlet of the nitric acid liquid tank, the other end of the first pipe fitting port 2 is connected to the solution delivery pump, the other end of the first pipe fitting port 3 is externally connected to a clean water storage tank, and the other end of the first pipe fitting port 4 is externally connected to a dry compressed air source, and a check valve and a solenoid valve are installed on the pipelines connecting the first pipe fitting port 1, the first pipe fitting port 3 and the first pipe fitting port 4 to the first pipe fitting port 2.

[0007] Preferably, the test solution outlet is connected to the solution emptying pump through a second pipe fitting, and the second pipe fitting includes a second pipe fitting port 1, a second pipe fitting port 2 and a second pipe fitting port 3. One end of the second pipe fitting port 2 and one end of the second pipe fitting port 3 are respectively connected to one end of the second pipe fitting port 1, the other end of the second pipe fitting port 1 is connected to the test solution outlet, the other end of the second pipe fitting port 2 is connected to the solution emptying pump, and the other end of the second pipe fitting port 3 is externally connected to a dry compressed air source. A check valve and a solenoid valve are installed on the pipelines connecting the second pipe fitting port 2 and the second pipe fitting port 3 to the second pipe fitting port 1.

[0008] Preferably, the reflux port of the nitric acid liquid tank is connected to the solution emptying pump through a third pipe fitting, and the third pipe fitting includes a third pipe fitting port 1, a third pipe fitting port 2 and a third pipe fitting port 3, one end of the third pipe fitting port 2 and one end of the third pipe fitting port 3 are respectively connected to one end of the third pipe fitting port 1, the other end of the third pipe fitting port 1 is connected to the solution emptying pump, the other end of the third pipe fitting port 2 is connected to the reflux port of the nitric acid liquid tank, and the other end of the third pipe fitting port 3 is externally connected to a washing water recovery component, and a check valve and a solenoid valve are installed on the pipelines connecting the third pipe fitting port 2 and the third pipe fitting port 3 with the third pipe fitting port 1.

[0009] Preferably, a liquid level sensor is installed inside the heat-conducting inner shell.

[0010] The beneficial effects of the present invention are as follows: the temperature of the temperature-controlled medium is regulated by the temperature regulating system, so that the temperature of the solution to be tested can be controlled to rise or fall; the heat exchange of the solution to be tested is accelerated by the setting of the stirring paddle, so that the solution to be tested is heated evenly; at the same time, the third temperature sensor is used to detect the solution to be tested in real time, so that the staff can grasp the temperature value of the solution to be tested in real time; and the photoelectric transmitter is used to emit a light signal, and the photoelectric receiver receives the light signal transmitted back by the solution to be tested, so as to grasp the crystallization condition of the solution to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the attached figure:

[0012] Figure 1 This is a structural schematic diagram of a nitric acid liquid crystallization point testing device proposed by the present invention;

[0013] Figure 2 This is a schematic diagram of the structure of the test assembly proposed in the utility model;

[0014] Figure 3 This is a structural diagram of the temperature control system proposed in the present invention;

[0015] Figure 4 This is a schematic structural diagram of the first pipe member proposed in the present utility model;

[0016] Figure 5 This is a schematic structural diagram of the second pipe member proposed in the present utility model;

[0017] Figure 6 This is a schematic structural diagram of the third pipe member proposed in the present utility model;

[0018] Figure 7 This is a graph showing the electrical signal feedback from the photoelectric receiver proposed in the present invention as the temperature changes.

[0019] In the figure: 1-nitric acid liquid tank, 2-test assembly, 3-temperature control system, 4-solution delivery pump, 5-solution emptying pump, 6-first pipe fitting, 7-second pipe fitting, 8-third pipe fitting;

[0020] Heating component, 32-cooling component, 33-circulating pump, 34-first temperature sensor, 35-second temperature sensor;

[0021] First pipe fitting port 1, 62-first pipe fitting port 2, 63-first pipe fitting port 3, 64-first pipe fitting port 4;

[0022] 71 - second pipe fitting port 1, 72 - second pipe fitting port 2, 73 - second pipe fitting port 3;

[0023] 81-third pipe fitting port 1, 82-third pipe fitting port 2, 83-third pipe fitting port 3;

[0024] 211-insulated housing, 212-temperature control medium inlet, 213-temperature control medium outlet;

[0025] 221 - heat-conducting inner shell, 222 - stirring paddle, 223 - test solution outlet, 224 - liquid level sensor, 225 - photoelectric transmitter, 226 - third temperature sensor, 227 - test solution inlet, 228 - photoelectric receiver, 229 - connecting frame. DETAILED DESCRIPTION

[0026] Reference Figure 1 A nitric acid liquid crystallization point testing device includes a nitric acid liquid tank 1, a testing component 2 and a temperature control system 3. The testing component 2 includes a heat-insulating outer shell 211 and a heat-conducting inner shell 221. The heat-conducting inner shell 221 is installed inside the heat-insulating outer shell 211. The outer wall of the heat-conducting inner shell 221 and the interior of the heat-insulating outer shell 211 form a temperature control cavity. The temperature control cavity is filled with a temperature control medium. A temperature control medium inlet 212 is provided at the lower part of the heat-insulating outer shell 211. A temperature control medium outlet 213 is provided on the side of the upper part of the heat-insulating outer shell 211 away from the temperature control medium inlet 212. The temperature control medium outlet 213 is connected to the inlet of the temperature control system, and the temperature control medium inlet 212 is connected to the outlet of the temperature control system.

[0027] Obviously, based on the above, in this embodiment, the temperature of the temperature-controlled medium is regulated by the temperature regulating system 3 , thereby achieving the temperature regulation of the solution to be tested inside the heat-conducting inner shell 221 .

[0028] Reference Figure 2 The heat-conducting inner shell 221 is provided with a test solution outlet 223 and a test solution inlet 227. The outlet of the nitric acid liquid tank 1 is connected to the test solution inlet 227 through the solution delivery pump 4, and the reflux port of the nitric acid liquid tank 1 is connected to the test solution outlet 223 through the solution emptying pump 5. Stirring paddles 222 are installed on both sides of the heat-conducting inner shell 221, a photoelectric transmitter 225 is installed on one side of the middle of the heat-conducting inner shell 221, and a photoelectric receiver 228 is installed at the position corresponding to the photoelectric transmitter 225 on the other side of the middle of the heat-conducting inner shell 221. A third temperature sensor 226 is also installed inside the heat-conducting inner shell 221.

[0029] Obviously, based on the above, in this embodiment, the setting of the stirring paddle 222 accelerates the heat exchange of the solution to be tested, so that the solution to be tested is heated evenly. At the same time, the third temperature sensor 226 is used to perform real-time detection of the solution to be tested, which is convenient for the staff to grasp the temperature value of the solution to be tested in real time, and the photoelectric transmitter 225 is used to emit a light signal, and the photoelectric receiver 228 receives the light signal transmitted back by the solution to be tested, so as to grasp the crystallization condition of the solution to be tested.

[0030] In this embodiment, there are at least two groups of photoelectric emitters 225 and photoelectric receivers 228. Each group of photoelectric emitters 225 and photoelectric receivers 228 are arranged opposite to each other. A lens group structure for straightening the light beam is provided at the front end of each photoelectric emitter 225.

[0031] Obviously, based on the above, by setting up multiple groups of photoelectric transmitters 225 and photoelectric receivers 228 to verify the accuracy of the data, and by setting up a lens group structure for straightening the light beam, the light emitted by each group of photoelectric transmitters 225 is parallel, reducing mutual interference.

[0032] In this embodiment, the stirring paddle 222 adopts a magnetic stirring paddle, and a magnetic driver is arranged on the outside of the heat-conducting inner shell 221 at the position of the center magnet of the magnetic stirring paddle. The stirring paddle 222 is driven to rotate by controlling the polarity change of the electromagnet, and the rotation speed of the stirring paddle 222 can be controlled by controlling the frequency of the polarity change.

[0033] Obviously, based on the above, the provision of the magnetic stirring paddle can prevent leakage from occurring at the connection between the heat-conducting inner shell 221 and the stirring paddle 222 .

[0034] In this embodiment, the heat-conducting inner shell 221 is fixed to the interior of the heat-insulating outer shell 211 via a connecting frame 229 .

[0035] Obviously, based on the above, the arrangement of the connecting frame 229 makes the fixing structure of the heat-conducting inner shell 221 more stable.

[0036] In this embodiment, refer to Figure 1 and Figure 3 The temperature control system 3 includes a heating component 31 and a cooling component 32. The temperature control medium inlet 212 is connected to the inlet of the heating component 31 and the inlet of the cooling component 32 respectively through a circulation pump 33 and a first temperature sensor 34 in sequence. The temperature control medium outlet 213 is connected to the outlet of the heating component 31 and the outlet of the cooling component 32 respectively through a second temperature sensor 35. The inlet and outlet of the heating component 31 and the inlet and outlet of the cooling component 32 are both installed with solenoid valves.

[0037] Obviously, based on the above, in this embodiment, the temperature control medium is able to circulate back and forth into the temperature control system 3 through the circulation pump 33 to control the temperature of the temperature control medium. At the same time, the solenoid valve controls the temperature control medium to enter the heating component 31 or the cooling component 32 to heat or cool the temperature control medium, so that the temperature control medium after temperature adjustment enters the temperature adjustment chamber, so that the temperature of the solution to be tested can be adjusted.

[0038] In this embodiment, the heating component 31 may be an electric heating tank, and the cooling component may be a liquid cooling tank.

[0039] Obviously, based on the above, the electric heating tank and the liquid cooling tank in this embodiment both adopt existing mature products and do not involve structural improvements, so they will not be elaborated here.

[0040] In this embodiment, refer to Figure 1 and Figure 4 The outlet of the nitric acid liquid tank 1 is connected to the solution delivery pump 4 through the first pipe fitting 6. The first pipe fitting 6 includes a first pipe fitting port 1 61, a first pipe fitting port 2 62, a first pipe fitting port 3 63 and a first pipe fitting port 4 64. One end of the first pipe fitting port 1 61, one end of the first pipe fitting port 3 63 and one end of the first pipe fitting port 4 64 are respectively connected to one end of the first pipe fitting port 2 62, the other end of the first pipe fitting port 1 61 is connected to the outlet of the nitric acid liquid tank 1, the other end of the first pipe fitting port 2 62 is connected to the solution delivery pump 4, the other end of the first pipe fitting port 3 63 is externally connected to a clean water storage tank, and the other end of the first pipe fitting port 4 64 is externally connected to a dry compressed air source. Check valves and solenoid valves are installed on the pipelines connecting the first pipe fitting port 1 61, the first pipe fitting port 3 63 and the first pipe fitting port 4 64 to the first pipe fitting port 2 62.

[0041] Obviously, based on the above, the provision of the first pipe 6 in this embodiment not only realizes the connection between the nitric acid liquid tank 1 and the solution delivery pump 4, but also realizes the introduction of clean water or dry compressed air, thereby achieving cleaning inside the device.

[0042] In this embodiment, refer to Figure 1 and Figure 5 The test solution outlet 223 is connected to the solution emptying pump 5 through the second pipe fitting 7. The second pipe fitting 7 includes a second pipe fitting port 1 71, a second pipe fitting port 2 72 and a second pipe fitting port 3 73. One end of the second pipe fitting port 2 72 and one end of the second pipe fitting port 3 73 are respectively connected to one end of the second pipe fitting port 1 71, and the other end of the second pipe fitting port 1 71 is connected to the test solution outlet 223, and the other end of the second pipe fitting port 2 72 is connected to the solution emptying pump 5. The other end of the second pipe fitting port 3 73 is externally connected to a dry compressed air source. A check valve and a solenoid valve are installed on the pipelines connecting the second pipe fitting port 2 72, the second pipe fitting port 3 73 and the second pipe fitting port 1 71.

[0043] Obviously, based on the above, in this embodiment, the test solution outlet 223 is connected to the solution draining pump 5 through the second pipe 7, and dry compressed air is also introduced, thereby achieving cleaning inside the device.

[0044] In this embodiment, refer to Figure 1 and Figure 6The reflux port of the nitric acid liquid tank 1 is connected to the solution drain pump 5 via a third pipe 8. The third pipe 8 includes a third pipe port 1 81, a third pipe port 2 82, and a third pipe port 3 83. One end of the third pipe port 2 82 and one end of the third pipe port 3 83 are respectively connected to one end of the third pipe port 1 81. The other end of the third pipe port 1 81 is connected to the solution drain pump 5. The other end of the third pipe port 2 82 is connected to the reflux port of the nitric acid liquid tank 1. The other end of the third pipe port 3 83 is externally connected to a wash water recovery assembly. Check valves and solenoid valves are installed on the pipelines connecting the third pipe port 2 82 and the third pipe port 3 83 to the third pipe port 1 81.

[0045] Obviously, based on the above, the provision of the third pipe fitting 8 in this embodiment not only realizes the connection between the reflux port of the nitric acid liquid tank 1 and the solution emptying pump 5, but also realizes the function of recycling washing water to avoid washing water polluting the environment.

[0046] In this embodiment, refer to Figure 2 A liquid level sensor 224 is installed inside the heat-conducting inner shell 221.

[0047] Obviously, based on the above, in this embodiment, the liquid level sensor 224 is provided to provide real-time feedback on the liquid level status inside the heat-conducting inner shell 221 , which is convenient for the operator to operate.

[0048] In order to more clearly illustrate the scheme and effect of this implementation, the following examples are provided with reference to the accompanying drawings:

[0049] Reference Figure 7 , Figure 7 The temperature corresponding to the vertical line is the crystallization point.

[0050] When the nitric acid liquid crystallization point test process begins, the heat-conducting inner shell 221 is preheated first, and the temperature control medium inside the heating component 31 is heated. When the temperature is heated to a preset temperature, the circulation pump 33 is turned on to pump the temperature control medium into the temperature adjustment chamber. When the third temperature sensor 226 reaches a preset temperature (this temperature is greater than the temperature of the solution to be tested in the nitric acid liquid tank 1), the preheating process is stopped, and the solution delivery pump 4 starts working to pump the solution to be tested in the nitric acid liquid tank 1 into the heat-conducting inner shell 221. The liquid level sensor 224 provides real-time feedback on the status of the liquid level inside the heat-conducting inner shell 221. When the liquid level inside the heat-conducting inner shell 221 reaches a preset position, the solution delivery pump 4 stops working, and the heating process begins to heat the temperature control medium inside the heating component 31. When the temperature is heated to a preset temperature, the circulation pump 33 is turned on to pump the temperature control medium into the temperature adjustment chamber. At the same time, the stirring paddle 222 works to accelerate the heat exchange of the solution to be tested, and the third temperature sensor 226 provides real-time feedback on the temperature of the solution to be tested. When the temperature of the solution to be tested reaches the preset temperature, the heating process stops, the stirring paddle 222 and the circulation pump 33 stop working, and the cooling process starts to cool the temperature control medium inside the cooling component 32. When the temperature drops to the preset temperature, the circulation pump 33 is turned on to pump the temperature control medium into the temperature adjustment chamber, and the photoelectric transmitter 225 and the photoelectric receiver 228 work, and the third temperature sensor 226 provides real-time feedback on the temperature of the solution to be tested. As the temperature of the solution to be tested continues to decrease, the light transmittance in the solution will gradually decrease. When the temperature of the solution to be tested approaches or reaches the crystallization point, the light transmittance of the solution will drop sharply due to the large amount of crystal precipitation, and the light signal received by the photoelectric receiver 228 will be significantly weakened. Figure 7 As shown, Figure 7 The temperature corresponding to the vertical line is the crystallization point.

[0051] During the heating process, the staff can set the target temperature and heating rate through the heating component 31, and provide real-time feedback on the temperature of the temperature control medium through the first temperature sensor 34 and the second temperature sensor 35. The staff can also regulate the heating component 31 so that the temperature control medium can heat the test solution at a stable heating temperature threshold.

[0052] During the cooling process, the staff can set the cooling target temperature and cooling rate through the cooling component 32, and provide real-time feedback on the temperature of the temperature control medium through the first temperature sensor 34 and the second temperature sensor 35. The staff can also regulate the cooling component 32 so that the temperature control medium can cool the test solution at a stable cooling temperature threshold.

Claims

1. A nitric acid liquid crystallization point testing device, characterized in that: The invention comprises a nitric acid liquid tank (1), a test assembly (2) and a temperature control system (3), wherein the test assembly (2) comprises a heat-insulating outer shell (211) and a heat-conducting inner shell (221), wherein the heat-conducting inner shell (221) is installed inside the heat-insulating outer shell (211), wherein the outer wall of the heat-conducting inner shell (221) and the interior of the heat-insulating outer shell (211) form a temperature control cavity, wherein the interior of the temperature control cavity is filled with a temperature control medium, wherein a temperature control medium inlet (212) is provided at the lower portion of the heat-insulating outer shell (211), and a temperature control medium outlet (213) is provided at a side of the upper portion of the heat-insulating outer shell (211) away from the temperature control medium inlet (212), wherein the temperature control medium outlet (213) is connected to the inlet of the temperature control system, and wherein the temperature control medium inlet (212) is connected to the temperature control system. The outlet of the system is connected, the heat-conducting inner shell (221) is provided with a test solution outlet (223) and a test solution inlet (227), the outlet of the nitric acid tank (1) is connected to the test solution inlet (227) through a solution delivery pump (4), and the reflux port of the nitric acid tank (1) is connected to the test solution outlet (223) through a solution emptying pump (5), stirring paddles (222) are installed on both sides of the heat-conducting inner shell (221), a photoelectric transmitter (225) is installed on one side of the middle of the heat-conducting inner shell (221), a photoelectric receiver (228) is installed on the other side of the middle of the heat-conducting inner shell (221) at a position corresponding to the photoelectric transmitter (225), and a third temperature sensor (226) is also installed inside the heat-conducting inner shell (221).

2. a kind of nitric acid liquid crystallization point testing device according to claim 1, is characterized in that: The temperature control system (3) includes a heating component (31) and a cooling component (32). The temperature control medium inlet (212) is connected to the inlet of the heating component (31) and the inlet of the cooling component (32) respectively through a circulation pump (33) and a first temperature sensor (34). The temperature control medium outlet (213) is connected to the outlet of the heating component (31) and the outlet of the cooling component (32) respectively through a second temperature sensor (35). The inlet and outlet of the heating component (31) and the inlet and outlet of the cooling component (32) are both installed with electromagnetic valves.

3. a kind of nitric acid liquid crystallization point testing device according to claim 1, is characterized in that: The outlet of the nitric acid liquid tank (1) is connected to the solution delivery pump (4) via a first pipe (6), wherein the first pipe (6) comprises a first pipe port 1 (61), a first pipe port 2 (62), a first pipe port 3 (63) and a first pipe port 4 (64), one end of the first pipe port 1 (61), one end of the first pipe port 3 (63) and one end of the first pipe port 4 (64) are respectively connected to one end of the first pipe port 2 (62), and the first pipe port 1 (61) is connected to one end of the first pipe port 2 (62). 1) is connected to the outlet of the nitric acid liquid tank (1), the other end of the first pipe fitting port 2 (62) is connected to the solution delivery pump (4), the other end of the first pipe fitting port 3 (63) is externally connected to a clean water storage tank, the other end of the first pipe fitting port 4 (64) is externally connected to a dry compressed air source, and the pipelines connecting the first pipe fitting port 1 (61), the first pipe fitting port 3 (63) and the first pipe fitting port 4 (64) to the first pipe fitting port 2 (62) are all installed with a check valve and a solenoid valve.

4. a kind of nitric acid liquid crystallization point testing device according to claim 1, is characterized in that: The test solution outlet (223) is connected to the solution emptying pump (5) through a second pipe (7), and the second pipe (7) includes a second pipe port 1 (71), a second pipe port 2 (72) and a second pipe port 3 (73). One end of the second pipe port 2 (72) and one end of the second pipe port 3 (73) are respectively connected to one end of the second pipe port 1 (71), the other end of the second pipe port 1 (71) is connected to the test solution outlet (223), the other end of the second pipe port 2 (72) is connected to the solution emptying pump (5), and the other end of the second pipe port 3 (73) is externally connected to a dry compressed air source. A check valve and a solenoid valve are installed on the pipelines connecting the second pipe port 2 (72) and the second pipe port 3 (73) to the second pipe port 1 (71).

5. a kind of nitric acid liquid crystallization point testing device according to claim 1, is characterized in that: The reflux port of the nitric acid liquid tank (1) is connected to the solution emptying pump (5) through a third pipe (8), and the third pipe (8) includes a third pipe port 1 (81), a third pipe port 2 (82) and a third pipe port 3 (83). One end of the third pipe port 2 (82) and one end of the third pipe port 3 (83) are respectively connected to one end of the third pipe port 1 (81), and the other end of the third pipe port 1 (81) is connected to the solution emptying pump (5). The other end of the third pipe port 2 (82) is connected to the reflux port of the nitric acid liquid tank (1), and the other end of the third pipe port 3 (83) is externally connected to a washing water recovery component. A check valve and a solenoid valve are installed on the pipelines connecting the third pipe port 2 (82) and the third pipe port 3 (83) to the third pipe port 1 (81).

6. a kind of nitric acid liquid crystallization point testing device according to claim 1, is characterized in that: A liquid level sensor (224) is installed inside the heat-conducting inner shell (221).

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