Quartz sand pickling reaction tank

Abstract

The utility model discloses a quartz sand pickling reaction tank, including a tank body, a material level meter, a first thermometer and a protective structure. The tank body has a containing cavity, the tank body is provided with a sand inlet, a first acid inlet, a sand outlet and an acid outlet connected with the containing cavity, the sand outlet and the acid outlet are arranged at the bottom of the tank body, the material level meter is arranged at the tank body, the material level meter can detect the material level in the containing cavity, the first thermometer is arranged at the tank body, the first thermometer can detect the material temperature in the containing cavity, the protective structure is arranged at the material level meter and the first thermometer, the protective structure can separate the material level meter and the first thermometer from the containing cavity, and the protective structure is made of polypropylene or polytrifluorochloroethylene or polyetheretherketone. The protective structure can separate the material level meter and the first thermometer from the containing cavity, and the polypropylene or polytrifluorochloroethylene or polyetheretherketone can resist acid corrosion and can block acid corrosion in the containing cavity to meet the above detection requirements.

Description

Technical Field

[0001] The utility model relates to the technical field related to quartz sand processing, in particular to a quartz sand pickling reaction tank. Background Art

[0002] The processing capacity of the quartz sand pickling reactor is determined during the design. If the amount of sand fed is too low, it will affect the production capacity and lead to an increase in costs. If the amount of sand fed is too high, it is easy to damage the tank body. In addition, the quartz sand needs to be heated during the pickling process, generally by heating the acid solution and heating the quartz sand through hot acid circulation. In the prior art, due to the strong corrosiveness of the acid solution, generally only a quantitative and constant temperature working mode can be adopted. First, the weight of the sand fed is weighed, and the acid solution temperature is preset before entering the reactor for reaction. Due to the large fluctuation in the water content of the quartz sand, the volume of the sand fed is difficult to measure accurately, and the acid solution temperature has a great influence on the reaction. Too low a temperature will slow down the reaction rate, and too high a temperature will cause an increase in energy consumption, and the equipment will undergo a large deformation, which will affect the service life of the acid supply pipeline and the reactor. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a quartz sand pickling reaction tank, which can reduce the cost of quartz sand reaction treatment.

[0004] The quartz sand pickling reaction tank according to the first embodiment of the utility model includes: a tank body, a level meter, a first thermometer and a protective structure, the tank body has a accommodating cavity, the tank body is provided with a sand inlet, a first acid inlet, a sand discharge port and an acid discharge port connected to the accommodating cavity, the sand discharge port and the acid discharge port are arranged at the bottom of the tank body, the level meter is arranged on the tank body, the level meter can detect the material level in the accommodating cavity, the first thermometer is arranged on the tank body, the first thermometer can detect the material temperature in the accommodating cavity, the protective structure is arranged on the level meter and the first thermometer, the protective structure can separate the level meter and the first thermometer from the accommodating cavity, and the protective structure is made of polypropylene or polytrifluorochloroethylene or polyetheretherketone.

[0005] The quartz sand pickling reaction tank according to the embodiment of the utility model has at least the following beneficial effects: sand is fed into the tank body through the sand inlet, and acid is fed into the tank body through the first acid inlet. After the reaction is completed, the sand discharge port is used to discharge the treated quartz sand, and the acid discharge port is used to discharge the acid liquid. By setting a level meter, the material level in the tank body can be detected, so that the amount of sand fed can be accurately controlled. The first thermometer can detect the temperature of the acid liquid, so that the temperature of the acid liquid can be accurately controlled, and then the reaction tank can react fully, which can reduce waste and reduce costs. The protective structure can separate the protective level meter and the first thermometer from the accommodating chamber. Polypropylene or polytrifluorochloroethylene or polyetheretherketone can resist acid corrosion and can block acid corrosion in the accommodating chamber to meet the above-mentioned detection requirements.

[0006] According to some embodiments of the present utility model, the protective structure includes a protective sleeve, the protective sleeve has a mounting groove, and the first thermometer is inserted into the mounting groove.

[0007] According to some embodiments of the present utility model, the protective structure further includes a protective layer, and the protective layer is arranged on the surface of the material level meter.

[0008] According to some embodiments of the present invention, the tank body is provided with a second acid inlet, the first acid inlet is provided at the top of the tank body, and the second acid inlet is provided at the side wall of the tank body.

[0009] According to some embodiments of the utility model, the side wall of the tank body is provided with a connecting pipe connected to the accommodating cavity, the opening of the connecting pipe is the second acid inlet, and the side wall of the connecting pipe is provided with a second thermometer, and the second thermometer can measure the temperature of the acid liquid at the second acid inlet.

[0010] According to some embodiments of the utility model, a filter assembly is provided in the accommodating chamber, and the filter assembly can separate the accommodating chamber into a reaction chamber and a filter chamber, the reaction chamber is directly connected to the first acid inlet, the sand inlet and the sand discharge port, and the filter chamber is directly connected to the acid discharge port.

[0011] According to some embodiments of the utility model, the filter assembly includes an acid filter cartridge having a filter groove opening downward, and the acid filter cartridge is connected to the bottom wall of the tank body so that the filter groove and the bottom wall of the tank body enclose the filter cavity.

[0012] According to some embodiments of the present invention, the side wall of the tank body is provided with an overflow port, and the overflow port is arranged close to the upper part of the tank body.

[0013] According to some embodiments of the utility model, an overflow weir is provided on the inner wall of the tank body, the overflow weir is annular, the overflow weir can form an annular groove between the inner wall of the tank body, and the overflow port is connected to the side wall of the annular groove.

[0014] According to some embodiments of the utility model, it also includes a control system, a sand feeding mechanism, an acid feeding device and an acid liquid heating device. The control system is electrically connected to the material level meter, the first thermometer, the second thermometer, the sand feeding mechanism, the acid feeding device and the acid liquid heating device. The sand feeding mechanism is connected to the sand inlet, and the sand feeding mechanism can transport quartz sand into the containing chamber through the sand inlet. The acid feeding device is connected to the first acid inlet and the second acid inlet, and the acid feeding device can transport acid liquid to the containing chamber. The acid liquid heating device is connected to the acid feeding device, and the acid liquid heating device can heat the acid liquid. The control system can control the switches of the sand feeding mechanism and the acid feeding mechanism according to the detection signal of the material level meter, and the control system can control the switch of the acid liquid heating device according to the detection signal of the first thermometer and the second thermometer.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 This is a schematic diagram of the overall cross-sectional structure of an embodiment of the utility model;

[0018] Figure 2 It is a top view of some embodiments of the utility model;

[0019] Figure 3 It is a schematic diagram of the internal structure of the tank;

[0020] Figure 4 It is a schematic diagram of the structure of the thermometer and the protective structure;

[0021] Figure 5 It is a structural diagram of the level meter and the protective structure.

[0022] Reference numerals:

[0023] Tank body 100, accommodating chamber 110, sand inlet 120, first acid inlet 130, sand outlet 140, acid outlet 150, second acid inlet 160, connecting pipe 170, filter assembly 180, acid filter cartridge 181, overflow port 190, overflow weir 191, annular groove 192;

[0024] Material level meter 200;

[0025] A first thermometer 310 and a second thermometer 320;

[0026] Protective sleeve 410 , mounting groove 411 , and protective layer 420 . DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Reference Figures 1 to 3According to the first embodiment of the utility model, the quartz sand pickling reaction tank includes a tank body 100, a level meter 200, a first thermometer 310 and a protective structure. The tank body 100 has a accommodating chamber 110. The tank body 100 is provided with a sand inlet 120, a first acid inlet 130, a sand discharge port 140 and an acid discharge port 150 connected to the accommodating chamber 110. The sand discharge port 140 and the acid discharge port 150 are arranged at the bottom of the tank body 100. The level meter 200 is arranged on the tank body 100. The level meter 200 can detect the material level in the accommodating chamber 110. The first thermometer 310 is arranged on the tank body 100. The first thermometer 310 can detect the material temperature in the accommodating chamber 110. The protective structure is arranged on the level meter 200 and the first thermometer 310. The protective structure can separate the level meter 200 and the first thermometer 310 from the accommodating chamber 110, and the protective structure is made of polypropylene or polytrifluorochloroethylene or polyetheretherketone. The tank body 100 is fed with sand through the sand inlet 120 and with acid through the first acid inlet 130. After the reaction is completed, the sand discharge port 140 is used to discharge the treated quartz sand, and the acid discharge port 150 is used to discharge the acid liquid. By setting the material level meter 200, the material level in the tank body 100 can be detected, so that the amount of sand fed can be accurately controlled. The first thermometer 310 can detect the temperature of the acid liquid, so that the temperature of the acid liquid can be accurately controlled, so that the reaction tank can react fully, waste can be reduced, and costs can be reduced. The material level meter 200 and the first thermometer 310 can be separated from the containing chamber 110 by a protective structure. Polypropylene or polytrifluorochloroethylene or polyetheretherketone can resist acid corrosion and can block acid corrosion in the containing chamber 110 to meet the above-mentioned detection requirements.

[0031] Specifically, the interior of the tank body 100 is a containing chamber 110, and a sand inlet 120 and a first acid inlet 130 can be set on the top of the tank body 100. Quartz sand is input into the containing chamber 110 from the sand inlet 120, and the acid is input into the containing chamber 110 from the first acid inlet 130. In addition, a connecting flange for installing a level meter 200 and a first thermometer 310 can be set on the top of the tank body 100. The level meter 200 can be a radar level meter 200, which can obtain the material level by calculating the time difference between the emission and reflection of electromagnetic waves, or it can be an ultrasonic level meter 200, which calculates the material height by calculating the speed of ultrasonic wave propagation in the air and the time difference between the reflection back. The first thermometer 310 can be a temperature measuring element such as a thermocouple or a thermal resistor. It can be understood that the corresponding length specification can be set so that it can be inserted into the material for temperature measurement. The protective structure can be made of polyetheretherketone (PEEK). Polyetheretherketone is a special polymer material belonging to the category of polymers. Its main chain structure contains a repeating unit of a ketone bond and two ether bonds. It can withstand a temperature of 250°C, resist chemical corrosion and is easy to process. A protective structure can be set on the level meter 200 and the first thermometer 310. The specific structure of the protective structure is not limited. It can block the acid in the accommodating chamber 110 and protect the level meter 200 and the first thermometer 310 from corrosion. In actual use, the level meter 200 can detect the material level height of quartz sand and acid in real time. When it reaches the predetermined position, it can stop the conveying in time, and the acid temperature can be detected in real time when the acid is input. If the temperature is too low, the heating power of the corresponding heating device can be increased. If the temperature is too high, the heating can be stopped. The pickling temperature can be kept within a suitable range. Through the above structure, the reaction conditions can be accurately detected, thereby reducing waste and reducing costs.

[0032] It is understandable that the protective structure may also be made of polypropylene or polychlorotrifluoroethylene, and it is also conceivable that the tank body 100 may also be provided with an observation hole and a manhole for maintenance.

[0033] Reference Figure 1 and Figure 4 In some embodiments of the present invention, the protective structure includes a protective sleeve 410, the protective sleeve 410 has a mounting groove 411, and the first thermometer 310 is inserted into the mounting groove 411. It is enough to protect the first thermometer 310 from corrosion.

[0034] Specifically, the first thermometer 310 can be provided with a long strip of temperature measuring probe, and the protective sleeve 410 can be configured to match the shape of the temperature measuring part of the first thermometer 310. The mounting groove 411 can accommodate the insertion of the temperature measuring probe of the first thermometer 310. It can be understood that heat transfer oil can be provided in the mounting groove 411, and the heat transfer oil can fill the gap and transfer heat in time, so that the first thermometer 310 can measure the temperature normally. The protective sleeve 410 can block the acid in the accommodating cavity 110, thereby protecting the first thermometer 310 from corrosion.

[0035] It is understandable that the first thermometer 310 may also be provided with a protective coating for protection.

[0036] Reference Figure 1 and Figure 5 In some embodiments of the present invention, the protective structure further includes a protective layer 420, which is disposed on the surface of the material level meter 200. The protective layer 420 can block the acid corrosion in the accommodating cavity 110, so that the material level meter 200 can work normally.

[0037] Specifically, the protective layer 420 can be a polyetheretherketone coating, which can be obtained by coating polyetheretherketone (PEEK) in powder form on the surface of an object, and utilizing processes such as high-temperature sintering or melt flow to make it adhere and form a uniform coating. The coating thickness can be as thin as one thousandth of an inch. The protective layer 420 will not affect the normal operation of the level meter 200, and can also block the acid corrosion in the accommodating cavity 110, so that the level meter 200 can operate normally.

[0038] Reference Figure 1 In some embodiments of the present invention, the tank body 100 is provided with a second acid inlet 160, the first acid inlet 130 is provided at the top of the tank body 100, and the second acid inlet 160 is provided at the side wall of the tank body 100. Specifically, the second acid inlet 160 can be provided at the lower part of the tank body 100 and connected to the side wall. It can be understood that the acid liquid can circulate and flow and heat, and the second acid inlet 160 and the acid outlet 150 can be provided with a circulation pipeline, and the acid liquid can circulate and heat and flow through the pump body and the heating component, so that the quartz sand can be fully pickled.

[0039] Reference Figure 1In some embodiments of the utility model, a connecting pipe 170 communicating with the accommodating chamber 110 is provided on the side wall of the tank body 100, and the opening of the connecting pipe 170 is the second acid inlet 160. A second thermometer 320 is provided on the side wall of the connecting pipe 170, and the second thermometer 320 can measure the temperature of the acid solution at the second acid inlet 160. Specifically, the side wall of the connecting pipe 170 can be connected to the second thermometer 320 through a tee, and the structure of the second thermometer 320 can be consistent with that of the first thermometer 310, and the second thermometer 320 is also provided with a protective structure, and the second thermometer 320 can detect the temperature of the acid solution at the second acid inlet 160. A circulating heating pipeline can be provided between the connecting pipe 170 and the acid discharge port 150, and only a pump body and a heating component can be provided in the pipeline. The second thermometer 320 can control the corresponding heating component switch so that the circulating acid solution can be kept within a certain temperature range, which is convenient for the quartz sand pickling reaction.

[0040] Reference Figure 1 and Figure 3 In some embodiments of the utility model, a filter assembly 180 is provided in the accommodating chamber 110, and the filter assembly 180 can separate the accommodating chamber 110 into a reaction chamber and a filter chamber, the reaction chamber is directly connected to the first acid inlet 130, the sand inlet 120 and the sand outlet 140, and the filter chamber is directly connected to the acid outlet 150. Specifically, the filter assembly 180 can filter the quartz sand, and the acid solution reacts with the quartz sand in the reaction chamber for pickling, and enters the filter chamber after being filtered by the filter assembly 180, and then can be connected from the acid outlet 150, so that the discharged acid solution does not carry quartz sand, which can be convenient for subsequent recycling.

[0041] Reference Figure 1 and Figure 3 In some embodiments of the present invention, the filter assembly 180 includes an acid filter cartridge 181, which has a filter groove opening downward, and is connected to the bottom wall of the tank body 100, so that the filter groove and the bottom wall of the tank body 100 enclose a filter cavity. The acid filter cartridge 181 can be easily disassembled and assembled, and can be easily maintained.

[0042] Specifically, the acid filter cartridge 181 may be provided with a filter screen, which can filter the quartz sand, and the acid filter cartridge 181 can be easily disassembled and assembled, and can be easily maintained.

[0043] Reference Figure 1 In some embodiments of the present invention, an overflow port 190 is provided on the side wall of the tank body 100, and the overflow port 190 is arranged near the upper part of the tank body 100. When the acid liquid is full of the overflow port 190, it can flow out through the overflow port 190, which can prevent the internal acid liquid from filling the entire containing cavity 110 and overflowing when the tank body 100 fails.

[0044] Reference Figure 1In some embodiments of the utility model, an overflow weir 191 is provided on the inner side wall of the tank body 100. The overflow weir 191 is annular. The overflow weir 191 can form an annular groove 192 with the inner side wall of the tank body 100. The overflow port 190 is connected to the side wall of the annular groove 192. Specifically, the overflow weir 191 can prevent the acid liquid in the accommodating chamber 110 from flowing out. The overflow weir 191 and the inner side wall of the tank body 100 form an annular groove 192. The overflow port 190 is on the side wall of the annular groove 192. When the acid liquid in the accommodating chamber 110 splashes, it can be blocked by the inner side of the overflow weir 191, which can reduce the splashing and outflow of the acid liquid.

[0045] In some embodiments of the present invention, a control system, a sand feeding mechanism, an acid feeding device and an acid liquid heating device are also included. The control system is electrically connected to the material level meter 200, the first thermometer 310, the second thermometer 320, the sand feeding mechanism, the acid feeding device and the acid liquid heating device. The sand feeding mechanism is connected to the sand feeding port 120. The sand feeding mechanism can transport quartz sand through the sand feeding port 120 into the containing chamber 110. The acid feeding device is connected to the first acid feeding port 130 and the second acid feeding port 160. The acid feeding device can transport acid liquid to the containing chamber 110. The acid liquid heating device is connected to the acid feeding device. The acid liquid heating device can heat the acid liquid. The control system can control the switch of the sand feeding mechanism and the acid feeding mechanism according to the detection signal of the material level meter 200. The control system can control the switch of the acid liquid heating device according to the detection signal of the first thermometer 310 and the second thermometer 320. The reaction conditions can be adjusted in real time to meet the reaction requirements.

[0046] Specifically, the sand feeding mechanism can be a quartz sand conveyor belt, which can transport quartz sand from the sand inlet 120 into the accommodating chamber 110. The acid feeding device can be composed of an acid storage tank, a conveying pipeline, a pump body, and a heating component. One end of the conveying pipeline can be connected to the first acid inlet 130 and the second acid inlet 160 respectively, and the other end can be connected to the acid discharge port 150. A pump body and a heating component are provided in the conveying pipeline. The specific structure is not described in detail here. The control system can control the start and stop of the gold sand mechanism and the acid feeding device according to the detection position of the material level meter 200, and can also control the heating power of the heating component according to the detection temperature of the first thermometer 310 and the second thermometer 320, so as to adjust the reaction conditions in real time to meet the reaction requirements.

[0047] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0048] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Quartz sand pickling reaction tank, characterized in that: include: A tank body (100) having a containing cavity (110) therein, the tank body (100) being provided with a sand inlet (120), a first acid inlet (130), a sand discharge port (140) and an acid discharge port (150) which are communicated with the containing cavity (110), the sand discharge port (140) and the acid discharge port (150) being arranged at the bottom of the tank body (100); A material level meter (200) is provided on the tank body (100), and the material level meter (200) is capable of detecting the material level in the containing cavity (110); A first thermometer (310) is disposed on the tank body (100), and the first thermometer (310) is capable of detecting the temperature of the material in the containing cavity (110); A protective structure is provided on the material level meter (200) and the first thermometer (310), the protective structure can separate the material level meter (200) and the first thermometer (310) from the accommodating chamber (110), and the protective structure is made of polypropylene or polychlorotrifluoroethylene or polyetheretherketone.

2. The quartz sand pickling reaction tank according to claim 1, characterized in that: The protection structure comprises a protection sleeve (410), the protection sleeve (410) having a mounting groove (411), and the first thermometer (310) is inserted into the mounting groove (411).

3. The quartz sand pickling reaction tank according to claim 2, characterized in that: The protective structure further comprises a protective layer (420), and the protective layer (420) is arranged on the surface of the material level meter (200).

4. The quartz sand pickling reaction tank according to claim 1, characterized in that: The tank body (100) is provided with a second acid inlet (160), the first acid inlet (130) is provided on the top of the tank body (100), and the second acid inlet (160) is provided on the side wall of the tank body (100).

5. The quartz sand pickling reaction tank according to claim 4, characterized in that: The side wall of the tank body (100) is provided with a connecting pipe (170) connected to the accommodating chamber (110); the opening of the connecting pipe (170) is the second acid inlet (160); the side wall of the connecting pipe (170) is provided with a second thermometer (320); the second thermometer (320) is capable of measuring the temperature of the acid solution at the second acid inlet (160).

6. The quartz sand pickling reaction tank according to claim 1, characterized in that: A filter assembly (180) is provided in the accommodating chamber (110), and the filter assembly (180) is capable of dividing the accommodating chamber (110) into a reaction chamber and a filter chamber, the reaction chamber is directly connected to the first acid inlet (130), the sand inlet (120) and the sand discharge port (140), and the filter chamber is directly connected to the acid discharge port (150).

7. The quartz sand pickling reaction tank according to claim 6, characterized in that: The filter assembly (180) comprises an acid filter cartridge (181), wherein the acid filter cartridge (181) has a filter groove opening downwardly, and the acid filter cartridge (181) is connected to the bottom wall of the tank body (100), so that the filter groove and the bottom wall of the tank body (100) enclose the filter cavity.

8. The quartz sand pickling reaction tank according to claim 1, characterized in that: The side wall of the tank body (100) is provided with an overflow port (190), and the overflow port (190) is arranged close to the upper part of the tank body (100).

9. The quartz sand pickling reaction tank according to claim 8, characterized in that: The inner wall of the tank body (100) is provided with an overflow weir (191), the overflow weir (191) is annular, the overflow weir (191) can form an annular groove (192) with the inner wall of the tank body (100), and the overflow port (190) is connected to the side wall of the annular groove (192).

10. The quartz sand pickling reaction tank according to claim 5, characterized in that: The invention also comprises a control system, a sand feeding mechanism, an acid feeding device and an acid liquid heating device. The control system is electrically connected to the material level meter (200), the first thermometer (310), the second thermometer (320), the sand feeding mechanism, the acid feeding device and the acid liquid heating device. The sand feeding mechanism is connected to the sand feeding port (120). The sand feeding mechanism can transport quartz sand into the containing chamber (110) through the sand feeding port (120). The acid feeding device is connected to the first acid feeding port (130) and the second acid feeding port (160). The acid feeding device can transport acid liquid to the containing chamber (110). The acid liquid heating device is connected to the acid feeding device. The acid liquid heating device can heat the acid liquid. The control system can control the switches of the sand feeding mechanism and the acid feeding device according to the detection signal of the material level meter (200). The control system can control the switches of the acid liquid heating device according to the detection signals of the first thermometer (310) and the second thermometer (320).

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