Constant weight measuring instrument

Abstract

The utility model relates to a constant weight measuring instrument which comprises a heat insulation and preservation container, a cooling layer, a bearing unit, a weighing unit, a transmission unit, an air supply unit and an exhaust unit, and a first cooling flow channel is arranged in the heat insulation and preservation container; the cooling layer is arranged outside the heat insulation container; dry gas or filtered air is introduced into the test cavity through the air supply unit, and high-temperature air in the test cavity is exhausted through the exhaust unit, so that the temperature in the test cavity is brought out, and the temperature of the test cavity is reduced; meanwhile, the testing cavity can be cooled through a cooling medium in a first cooling flow channel arranged in the heat insulation and preservation container; besides, the test cavity is further cooled through a cooling layer arranged outside the heat insulation and preservation container, so that the interior of the test cavity is rapidly cooled to a weighable temperature, and the weighing efficiency is improved; and through the cooperation of the transmission unit and the weighing unit, the weighing operation of the weighing unit is realized, and the weighing efficiency is further improved.

Description

Technical Field

[0001] This application relates to the technical field of sample weighing, and particularly to a constant weight measuring instrument. Background Art

[0002] In the constant weight measurement experiment, it is necessary to evaporate, dry, and incinerate the sample to remove volatile and organic components in the sample. When the deviation between the weights of the sample in two consecutive weighings is less than the preset value, the mass obtained in the latter weighing can be determined as the constant weight value of the sample. The traditional constant weight measurement method is manual operation, and the measurement efficiency is relatively low. Summary of the Invention

[0003] Based on this, in view of the problem of low measurement efficiency existing in the existing weighing devices, it is necessary to provide a constant weight measuring instrument.

[0004] A constant weight measuring instrument includes:

[0005] A heat-insulating and heat-preserving chamber having a test cavity; a first cooling channel is arranged in the heat-insulating and heat-preserving chamber;

[0006] A cooling layer is arranged outside the heat-insulating and heat-preserving chamber and is used for heat exchange with the heat-insulating and heat-preserving chamber;

[0007] A supporting unit is located in the test cavity, and the supporting unit is used for supporting the sample to be measured;

[0008] A weighing unit, part of which is located in the test cavity, and the weighing unit is used for weighing the sample to be measured;

[0009] A transmission unit, the supporting unit is connected to the transmission unit, and the transmission unit is used to drive the supporting unit to separate from or contact the weighing unit;

[0010] A gas supply unit and an exhaust unit, both of which are communicated with the test cavity. The gas supply unit is used to introduce gas into the test cavity, and the exhaust unit is used to discharge the gas in the test cavity.

[0011] In one embodiment, the gas supply unit includes a filling pipe connected to the test cavity and a protective gas filling part connected to the filling pipe;

[0012] The exhaust unit includes a discharge pipe and a tail gas treatment part connected to the discharge pipe.

[0013] In one embodiment, a heating part is arranged on the cavity wall of the test cavity, and the heating part is used to heat the test cavity.

[0014] In one embodiment, the supporting unit includes a crucible and a sample tray connected to the transmission unit; the crucible can be separated from the sample tray under the supporting action of the weighing unit.

[0015] In one embodiment, the transmission unit includes a driving part and a transmission shaft connected between the driving part and the sample tray; a cooling sleeve is sleeved on the transmission shaft.

[0016] In one embodiment, the weighing unit includes a balance and a sample support rod arranged on the balance, and a part of the sample support rod is located in the test chamber.

[0017] In one embodiment, the constant weight measuring instrument further includes a support rod lifting unit. When in the lifting state, the support rod lifting unit moves upward to connect with the sample support rod to drive the sample support rod to separate from the balance; when in the weighing state, the support rod lifting unit moves downward to separate from the sample support rod; and / or

[0018] The heat-insulating and heat-preserving liner is configured with a through hole for the sample support rod to pass through; the sample support rod includes a conical plugging part for plugging the through hole.

[0019] In one embodiment, the constant weight measuring instrument further includes a seal arranged between the balance and the heat-insulating and heat-preserving liner, and a part of the sample support rod is located within the seal;

[0020] An air pipe interface is arranged on the seal, and the air pipe interface is connected with an air inlet pipe for introducing dry gas; a valve for controlling on / off is arranged on the air inlet pipe.

[0021] In one embodiment, at least two groups of the weighing unit and the supporting unit are provided, and each weighing unit corresponds to a supporting unit one by one.

[0022] In one embodiment, the constant weight measuring instrument further includes an auxiliary solvent filling unit communicated with the test chamber; and / or

[0023] The constant weight measuring instrument further includes a furnace cover for closing or opening the test chamber; and / or

[0024] The constant weight measuring instrument further includes a cooling fan located in the transmission chamber of the constant weight measuring instrument; and / or

[0025] The constant weight measuring instrument further includes traveling wheels arranged at the bottom of the housing.

[0026] The above constant weight measuring instrument introduces dry gas or filtered air into the interior of the test chamber through the air supply unit, and discharges the high-temperature air in the test chamber through the exhaust unit, thereby taking out the temperature inside the test chamber and reducing the temperature of the test chamber. At the same time, the cooling medium in the first cooling channel arranged in the heat insulation and heat preservation liner can cool the test chamber. In addition, the temperature reduction layer arranged outside the heat insulation and heat preservation liner further cools the test chamber, so as to quickly reduce the temperature inside the test chamber to the weighable temperature, improving the weighing efficiency. Furthermore, through the cooperation of the transmission unit and the weighing unit, the weighing operation of the weighing unit is realized, further improving the weighing efficiency. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the constant weight measuring instrument provided by the first embodiment of the present application.

[0028] Figure 2 is Figure 1 a schematic diagram of part A in the constant weight measuring instrument shown.

[0029] Reference numerals in the drawings: 10, constant weight measuring instrument; 100, housing; 110, heat insulation and heat preservation liner; 111, test chamber; 112, first cooling channel; 120, transmission chamber; 130, furnace cover; 140, walking wheels; 150, leveling feet; 160, temperature reduction layer; 200, supporting unit; 210, crucible; 220, sample tray; 300, weighing unit; 310, balance; 320, sample support rod; 321, conical sealing part; 330, seal; 340, inlet pipe; 350, support rod lifting unit; 400, transmission unit; 410, driving part; 420, transmission shaft; 430, cooling sleeve; 500, air supply unit; 510, filling pipe; 520, protective gas filling part; 600, exhaust unit; 610, discharge pipe; 620, tail gas treatment part; 710, heating part; 720, cooling fan. Detailed Embodiments

[0030] In order to make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed embodiments of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0031] In the description of the present application, it should be understood that if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present application 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 thus should not be construed as a limitation on the present application.

[0032] In addition, if there are terms such as "first" and "second", these terms are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if there is a term "plurality", the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0033] In the present application, unless otherwise clearly specified and limited, if there are terms such as "mounted", "connected", "connected to", "fixed", etc., these terms should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] In the present application, unless otherwise clearly specified and limited, if there is a description such as a first feature being "above" or "below" a second feature, the meaning may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0035] It should be noted that if an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0036] Referring to Figure 1 As shown, the constant weight measuring instrument 10 provided by an embodiment of the present application includes a housing 100, a heat insulation and heat preservation bladder 110 disposed in the housing 100, a cooling layer 160, a supporting unit 200, a weighing unit 300, a transmission unit 400, a gas supply unit 500 and an exhaust unit 600. The heat insulation and heat preservation bladder 110 has a test chamber 111; a first cooling flow channel 112 is provided in the heat insulation and heat preservation bladder 110; the cooling layer 160 is disposed outside the heat insulation and heat preservation bladder 110 and is used for heat exchange with the heat insulation and heat preservation bladder 110; the supporting unit 200 is located in the test chamber 111, and the supporting unit 200 is used for supporting the sample to be measured; a part of the weighing unit 300 is located in the test chamber 111, and the weighing unit 300 is used for weighing the sample to be measured; the supporting unit 200 is connected to the transmission unit 400, and the transmission unit 400 is used to drive the supporting unit 200 to separate from or contact the weighing unit 300; both the gas supply unit 500 and the exhaust unit 600 are communicated with the test chamber 111. The gas supply unit 500 is used to introduce gas into the test chamber 111, and the exhaust unit 600 is used to discharge the gas in the test chamber 111.

[0037] The above constant weight measuring instrument 10 introduces dry gas or filtered air into the interior of the test chamber 111 through the gas supply unit 500, and discharges the high-temperature air in the test chamber 111 through the exhaust unit 600, thereby taking out the temperature inside the test chamber 111 and reducing the temperature of the test chamber 111. At the same time, the cooling medium in the first cooling channel 112 provided in the heat-insulating and heat-preserving liner 110 can cool the test chamber 111. In addition, the temperature reduction layer 160 provided outside the heat-insulating and heat-preserving liner 110 further cools the test chamber 111, so as to quickly reduce the temperature inside the test chamber 111 to the weighable temperature and improve the weighing efficiency. Furthermore, through the cooperation of the transmission unit 400 and the weighing unit 300, the weighing operation of the weighing unit 300 is realized, further improving the weighing efficiency. At the same time, after the sample is processed or experimented in the test chamber 111, it can be weighed in the test chamber 111 without transferring the sample, avoiding the influence or interference of the external environment on the sample during the transfer process and ensuring the accuracy of weighing. Among them, the temperature reduction layer 160 can be a structure such as a semiconductor refrigeration sheet or a cold plate for supplying cooling water to flow through, and there is no limitation here.

[0038] Referring to Figure 1 As shown, in one embodiment, the gas supply unit 500 includes a filling pipe 510 connected to the test chamber 111 and a protective gas filling part 520 connected to the filling pipe 510; through the cooperation of the protective gas filling part 520 and the filling pipe 510, the protective gas is introduced into the test chamber 111 to adapt to the application scenario where the sample needs to be protected by the protective gas during the processing. At the same time, after the protective gas is introduced into the test chamber 111, it can also exchange heat with the gas in the test chamber 111, so as to quickly cool the test chamber 111 to the weighable temperature.

[0039] Referring to Figure 1 As shown, in one embodiment, the exhaust unit 600 includes a discharge pipe 610 and a tail gas treatment part 620 connected to the discharge pipe 610. Through the discharge pipe 610 and the tail gas treatment part 620, the high-temperature and high-humidity gas in the test chamber 111 is discharged to prevent the high-temperature and high-humidity gas from affecting the measurement accuracy of the weighing unit 300. At the same time, the tail gas treatment part 620 can neutralize the discharged waste gas, reduce the risk of environmental pollution caused by the direct discharge of waste gas, and improve the environmental protection performance.

[0040] Referring to Figure 1As shown, in one embodiment, a heating part 710 is provided on the cavity wall of the test cavity 111. The heating part 710 is used to heat the air in the test cavity 111. Through the heat exchange between the heating part 710 and the air in the test cavity 111, the test cavity 111 can be quickly heated to the experimental temperature. Further, a temperature measuring element such as a temperature sensor can be provided in the test cavity 111 to detect the temperature in the test cavity 111 in real time, ensuring that the temperature in the test cavity 111 does not exceed the preset range. The heating part 710 can be a heating wire wound around the cavity wall of the test cavity 111, or can be suspended in the test cavity 111.

[0041] Referring to Figure 1 As shown, the constant weight measuring instrument 10 further includes a cooling fan 720. The cooling fan 720 is located in the transmission cavity 120 of the constant weight measuring instrument 10. The transmission cavity 120 is ventilated and cooled by the cooling fan 720 to ensure the reliability of the use of the transmission unit 400.

[0042] Referring to Figure 1 As shown, in one embodiment, the supporting unit 200 includes a crucible 210 and a sample tray 220 connected to the transmission unit 400; the sample tray 220 is driven by the transmission unit 400 to descend, so that the crucible 210 can be lapped on the weighing unit 300. As the transmission unit 400 drives the sample tray 220 to continue descending, the sample tray 220 will gradually separate from the crucible 210, thereby transferring the crucible 210 to the weighing unit 300. The crucible 210 is in a stepped cylindrical shape, its top can be clamped on the sample tray 220, and the bottom of the crucible 210 passes through the sample tray 220, facilitating the transfer of the crucible 210 onto the sample tray 220 or separating it from the sample tray 220.

[0043] In one embodiment, the transmission unit 400 includes a driving part 410 and a transmission shaft 420 connected between the driving part 410 and the sample tray 220. The transmission shaft 420 and the sample tray 220 are rigidly connected, so that the sample tray 220 is driven to act through the transmission shaft 420. The transmission shaft 420 can be a single shaft connected between the sample tray 220 and the transmission unit 400. Of course, the transmission shaft 420 can also be spliced in sections by multiple shafts. Further, a cooling sleeve 430 is sleeved on the transmission shaft 420 to cool and insulate, reducing the possibility of the internal heat of the test cavity 111 being transferred to the driving part 410 and improving the service life.

[0044] In some embodiments, the transmission unit 400 can include a hydraulic cylinder, a cylinder or other lifting driving parts 410 with lifting functions, so that the sample tray 220 can rise or fall; the transmission unit 400 can also include a rotating driving part 410 with rotating functions such as a motor, so that the sample tray 220 rotates, thereby transferring the crucible 210 to the next working station.

[0045] Refer to Figure 1 As shown, in one embodiment, the weighing unit 300 includes a balance 310 and a sample support rod 320 disposed on the balance 310. A part of the sample support rod 320 is located in the test chamber 111, and the balance 310 is located in the transmission chamber 120. The weighing operation is achieved by connecting or separating the sample support rod 320 from the crucible 210. The sample support rod 320 can be made of ceramic or other heat-insulating materials to avoid transferring heat to the balance 310. In other embodiments, the weighing unit 300 can also be a weighing sensor or other components or elements capable of weighing an object.

[0046] In one embodiment, the constant weight measuring instrument 10 further includes a support rod lifting unit 350. When in the lifted state, the support rod lifting unit 350 can move upward to connect with the sample support rod 320 to lift the sample support rod 320 and separate it from the balance 310; when the support rod lifting unit 350 descends, the sample support rod 320 descends and is placed on the tray of the balance 310 for weighing. That is to say, when in the weighing state, that is, when the sample support rod 320 is in contact with the balance 310, the support rod lifting unit 350 will continue to descend to separate from the sample support rod 320. Specifically, when weighing is not required, the support rod lifting unit 350 is used to separate the sample support rod 320 from the balance 310, which can avoid the sample support rod 320 contacting the balance 310 for a long time and affecting the weighing accuracy of the balance 310, and can also avoid the balance 310 vibrating during the lifting and lowering process, thus affecting its stability and reliability and ensuring the weighing accuracy of the balance 310; and by separating the sample support rod 320 from the balance 310, it can also avoid the high-temperature heat generated during the sample processing being transferred to the balance 310 through the sample support rod 320, and can also ensure the weighing accuracy of the balance 310. The tray lifting unit can be a cylinder, a linear electrode, etc.

[0047] Refer to Figure 2 As shown, in some embodiments, the heat-insulating and heat-preserving liner is configured with a through-hole for the sample support rod 320 to pass through; the sample support rod 320 includes a conical plugging portion 321, and the conical plugging portion 321 can plug the through-hole to ensure the sealing performance of the test chamber 111 and ensure the stability and reliability of the sample processing.

[0048] In some embodiments, a positioning portion is provided between the weighing unit 300 and the supporting unit 200. In this way, when the transmission unit 400 drives the supporting unit 200 to lift and lower, the positioning cooperation between the positioning portions is utilized to make the weighing unit 300 contact and cooperate with the supporting unit 200 more accurately and reliably, thereby ensuring the weighing accuracy.

[0049] Refer to Figure 1As shown, in one embodiment, the constant weight measuring instrument 10 further includes a seal 330 disposed at the bottom of the balance 310 and the test chamber 111, and a part of the sample support rod 320 is located within the seal 330. By providing the seal 330, the test chamber 111 is isolated from the transmission chamber 120, ensuring the sealing performance of the test chamber 111. The sample support rod 320 is processed from a material with a low thermal conductivity coefficient, such as zirconia ceramics, and the sample support rod 320 can be connected to the balance 310 by means of heat insulation with a small contact area.

[0050] Referring to Figure 1 As shown, in one embodiment, an air pipe interface is provided on the seal 330, and the air pipe interface is connected to an inlet air pipe 340. The inlet air pipe 340 is used to introduce dry gas such as dry air, nitrogen, or inert gas, etc.; the air pipe interface is used to introduce dry gas to form a gas flexible seal, preventing the high-temperature and high-humidity gas inside the test chamber 111 from contacting the balance 310, thereby playing a role in protecting the balance 310, and being able to prevent the measurement result of the balance 310 from being interfered by the experimental environment and improving the measurement accuracy of the balance 310.

[0051] Further, the inlet air pipe 340 is provided with a valve for controlling the on-off. The valve can specifically be a solenoid valve, and the on-off of the dry gas is controlled by the solenoid valve. When weighing, the solenoid valve is closed, that is, the introduction of dry gas is stopped, so that the test chamber 111 cavity forms a closed test chamber 111.

[0052] Referring to Figure 1 As shown, in one embodiment, at least two sets of the weighing unit 300 and the supporting unit 200 are provided, and each weighing unit 300 corresponds to one supporting unit 200. Specifically, a plurality of crucibles 210 are provided on the sample tray 220. For example, crucibles 210 are provided on both the inner and outer circles of the sample tray 220, and balances 310 are arranged on the inner and outer circles respectively, so that two groups of samples can be weighed simultaneously, improving the weighing efficiency. Further, the two balances 310 can be respectively arranged at both ends of the sample tray 220, reducing the possibility of interference between the balances 310 and enabling the layout of the weighing device to be more compact.

[0053] Referring to Figure 1 As shown in one embodiment, the constant weight measuring instrument 10 further includes an auxiliary solvent adding unit communicated with the test chamber 111. During the ignition process, auxiliary solvents such as sulfuric acid and magnesium acetate need to be added to the sample to accelerate the carbonization and dissolution of the sample and improve the experimental efficiency.

[0054] Referring to Figure 1As shown, in one embodiment, the constant weight measuring instrument 10 further includes a furnace cover 130 connected to the heat-insulating chamber 110, and the furnace cover 130 is used to close or open the test chamber 111. Specifically, the furnace cover 130 is detachably connected to the housing 100, so that the crucible 210 can be easily taken out and placed. Furthermore, an observation glass is provided on the furnace cover 130, and the observation glass has heat insulation and visibility, and is used for the experimenter to observe the condition of the crucible 210.

[0055] See also Figure 1 As shown, in some embodiments, the constant weight measuring instrument 10 further includes a running wheel 140 disposed at the bottom of the housing 100. Through the running wheel 140, the experimenter can transport the constant weight measuring instrument 10 to other places, thereby improving the convenience of the weighing operation. Furthermore, a leveling foot 150 is also provided at the bottom of the housing 100, through which the leveling foot 150 can adjust the level of the entire device to ensure the reliability of the weighing result.

[0056] In one embodiment, a water bath (not shown) may be provided at the bottom of the test chamber 111, and water may be filled and drained inside the water bath. When there is no heating portion 710 at the bottom, the water heating rod may be directly immersed in water to heat the water directly; when a heating portion 710 is provided at the bottom, the water bath may be attached to the heating portion 710, and the heating rod immersed in the water may be retained or removed, so that the constant weight measuring instrument 10 may be transformed into a water bath constant weight measuring instrument 10 with a water bath function, which is suitable for samples that need to be dried in a water bath. The water inside the water bath may be water heated externally and injected into the water bath, which can speed up the experimental efficiency.

[0057] Taking the constant weight measuring instrument 10 as an ignition constant weight instrument as an example, at the beginning of the experiment, the furnace cover 130 of the test chamber 111 is opened, the empty crucible 210 is placed on the sample tray 220 according to the number, and the furnace cover 130 of the test chamber 111 is closed. Then, the inside of the test chamber 111 is heated to the ignition temperature through the heating part 710; at the same time, the inert gas or dry air is blown out through the air pipe interface to isolate the hot air from contacting the balance 310. After a specified time, the gas of the test chamber 111 is introduced through the protective gas filling part 520, and discharged from the exhaust gas treatment part 620, bringing out the internal temperature, and the cooling medium in the first cooling channel 112 set in the heat insulation tank 110 can cool the test chamber 111; and the cooling layer 160 set outside the heat insulation tank 110 is used to further cool the test chamber 111, so that it can be quickly cooled to a weighable temperature.

[0058] Next, the sample support rod 320 is controlled by the support rod lifting unit 350 to descend and be placed on the tray of the balance 310. The transmission unit 400 controls the sample tray 220 to drive the crucible 210 to lift and rotate, and the empty sample crucible 210 after ignition is placed on the sample support rod 320 one by one; when the weighing is stable, the data of the balance 310 is read to end the weighing.

[0059] Further, the furnace cover 130 of the test chamber 111 is opened, the experimental sample is placed in the corresponding crucible 210, and the furnace cover 130 of the test chamber 111 is closed. Then, the above-mentioned ignition and cooling steps are repeated until the crucibles 210 are all of constant weight.

[0060] Among them, if the difference between the weighing value this time and the weighing value last time is within the preset difference range, it is considered that the weighing value this time is the constant weight value of the sample; if the difference between the weighing value this time and the weighing value last time is not within the preset difference range, then repeat the heating by the heating unit 710 followed by cooling and weighing with the balance 310 until the difference between the current weighing value and the previous weighing value is within the preset difference range, and it is considered that the weighing value of the latter weighing is the constant weight value of the sample.

[0061] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0062] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A constant weight measuring instrument, characterized in that: The constant weight measuring instrument comprises: A heat-insulating container (110) having a test cavity (111); a first cooling channel (112) is provided in the heat-insulating container (110); A cooling layer (160) is arranged outside the heat-insulating liner (110) and is used for performing heat exchange with the heat-insulating liner (110); A supporting unit (200), located in the test cavity (111), the supporting unit (200) being used to support a sample to be tested; A weighing unit (300), partly located in the test cavity (111), the weighing unit (300) being used to weigh a sample to be tested; a transmission unit (400), the supporting unit (200) being connected to the transmission unit (400), the transmission unit (400) being used to drive the supporting unit (200) to separate from or contact the weighing unit (300); The gas supply unit (500) and the exhaust unit (600) are both in communication with the test chamber (111); the gas supply unit (500) is used to introduce gas into the test chamber (111), and the exhaust unit (600) is used to exhaust gas from the test chamber (111).

2. The constant weight measuring instrument according to claim 1, characterized in that: The gas supply unit (500) comprises a filling pipe (510) connected to the test chamber (111) and a protective gas filling portion (520) connected to the filling pipe (510); The exhaust unit (600) comprises an exhaust pipe (610) and an exhaust gas treatment unit (620) connected to the exhaust pipe (610).

3. The constant weight measuring instrument according to claim 1, characterized in that: A heating portion (710) is provided on the cavity wall of the test cavity (111), and the heating portion (710) is used to heat the test cavity (111).

4. The constant weight measuring instrument according to claim 1, characterized in that: The supporting unit (200) comprises a crucible (210) and a sample plate (220) connected to the transmission unit (400); the crucible (210) can be separated from the sample plate (220) under the support of the weighing unit (300).

5. The constant weight measuring instrument according to claim 4, characterized in that: The transmission unit (400) comprises a driving part (410) and a transmission shaft (420) connected between the driving part (410) and the sample plate (220); a cooling sleeve (430) is sleeved on the transmission shaft (420).

6. The constant weight measuring instrument according to claim 5, characterized in that: The weighing unit (300) comprises a balance (310) and a sample support rod (320) arranged on the balance (310), and a portion of the sample support rod (320) is located in the test cavity (111).

7. The constant weight measuring instrument according to claim 6, characterized in that: The constant weight measuring instrument further comprises a support rod lifting unit (350), and when in a lifting state, the support rod lifting unit (350) moves upward to connect with the sample support rod (320) to drive the sample support rod (320) to separate from the balance (310); when in a weighing state, the support rod lifting unit (350) moves downward to separate from the sample support rod (320); and / or The heat-insulating container (110) is provided with a through hole for the sample support rod (320) to pass through; the sample support rod (320) comprises a conical blocking portion (321), and the conical blocking portion (321) is used to block the through hole.

8. The constant weight measuring instrument according to claim 7, characterized in that: The constant weight measuring instrument further comprises a sealing member (330) arranged between the balance (310) and the heat-insulating container (110), and a portion of the sample support rod (320) is located within the sealing member (330); The sealing member (330) is provided with an air pipe interface, the air pipe interface is connected to an air inlet pipe (340), the air inlet pipe (340) is used to introduce dry gas; the air inlet pipe (340) is provided with a valve for controlling on and off.

9. The constant weight measuring instrument according to claim 1, characterized in that: At least two groups of the weighing units (300) and the supporting units (200) are provided, and each weighing unit (300) corresponds to one supporting unit (200) on a one-to-one basis.

10. The constant weight measuring instrument according to claim 1, characterized in that: The constant weight measuring instrument further comprises an auxiliary solvent filling unit connected to the test chamber (111); and / or The constant weight measuring instrument further comprises a furnace cover (130) for closing or opening the test chamber (111); and / or The constant weight measuring instrument further comprises a cooling fan (720), wherein the cooling fan (720) is located in the transmission cavity (120) of the constant weight measuring instrument; and / or The constant weight measuring instrument further comprises a running wheel (140) arranged at the bottom of the housing (100).

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