Sample dispenser and sample dispensing device comprising same

Abstract

A sample dispenser and a sample dispensing device comprising same. The sample dispenser (10) comprises a reagent bottle (100) used for storing a powdered reagent, and a dispensing mechanism (200) communicated with the reagent bottle (100) and used for transferring the powdered reagent from the inside of the reagent bottle (100) to the outside. The dispensing mechanism (200) comprises a first passage (210) communicated with the reagent bottle (100), a first screw (220) arranged inside the first passage (210), a second passage (230) communicated with the first passage (210) in an up-down misaligned manner, and a second screw (240) arranged inside the second passage (230); the first screw (220) is used for rotating and comprises a first-screw first threaded section (221) and a first-screw second threaded section (222) which have opposite rotating directions, so as to respectively transfer the powdered reagent inside the first passage (210) to the second passage (230) and the reagent bottle (100); and the second screw (240) is also used for rotating, so as to transfer the powdered reagent inside the second passage (230) to the outside. The present invention achieves high-precision powder dispensing while avoiding regent accumulation inside the sample dispenser (10) during powder dispensing processes, and meanwhile, occupies less space, thus helping to save costs and being more suitable for small-dose and high-precision powder dispensing requirements.

Description

Sample injector and sample injecting device containing the same Technical Field

[0001] The present invention relates to the technical field of sample addition and metering, and in particular to a sample adder and a sample adding device comprising the same. Background Art

[0002] As is well known, in biochemical experiments, reagents, especially powdered reagents, need to be frequently weighed and sampled. Currently, weighing balances are commonly used in the prior art for weighing reagents. However, weighing balances require manual operation, which not only results in low accuracy but also large errors. At the same time, due to manual operation, each operation relies on human sense to take samples, and it may be difficult to achieve the ideal weighing and sampling effect after multiple operations. Moreover, due to manual operation, reagents may fall or scatter during the sampling movement, which not only leads to reagent waste but also may cause reagent contamination. As a result, automated sampling equipment has received widespread attention from experimenters in recent years. However, for automated sampling equipment, due to its high accuracy and small powder output, it is easy to cause a backlog of powdered reagents during the powder output process, thereby affecting the operation of the sampling equipment.

[0003] Patent document CN115508575A discloses a sampler. The sampler includes a sampler mechanism. The sampler mechanism uses two screws with opposite thread rotation directions, which are used to deliver powder and return powder while discharging powder. That is, the first screw is used to deliver powder, and the second screw is used to return powder while discharging powder. This achieves high-precision powder discharging while reducing powder backlog. However, there are still some problems in its actual use. For example, the entire sampler mechanism is relatively large, and while considering reducing the volume, the backlog of powder reagents must also be taken into account.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide a sampler and a sampler device comprising the same. The sampler adopts two screws, wherein the first screw first performs powder feeding and powder returning operations simultaneously, and the second screw then performs powder discharge operation, which not only realizes high-precision powder discharge, but also avoids powder blockage caused by the accumulation of powder reagents in the sampler during the powder discharge process, thereby ensuring the normal operation, working accuracy and working stability of the sampler and the sampler device; at the same time, the sampler occupies a small space, which is not only conducive to cost saving, but also more suitable for small-dose, high-precision powder discharge requirements.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One aspect of the present invention is to provide a sample injector, comprising a reagent bottle suitable for storing a powdered reagent and a dispensing mechanism connected to the reagent bottle and suitable for conveying the powdered reagent from the reagent bottle outward, the dispensing mechanism comprising a first channel connected to the reagent bottle, a first screw arranged in the first channel, a second channel connected to the first channel in an upper and lower offset manner, and a second screw arranged in the second channel; the first screw is suitable for rotating and comprises a first thread segment of the first screw and a second thread segment of the first screw with opposite rotation directions to convey the powdered reagent in the first channel to the second channel and the reagent bottle, respectively; the second screw is also suitable for rotating to output the powdered reagent in the second channel outward.

[0008] Optionally, the reagent bottle is adapted to rotate so as to deliver powdered reagent to the first channel.

[0009] Optionally, the upper end of the first channel extends into the reagent bottle, and is provided with a powder inlet connected to the reagent bottle to receive powdered reagent from the reagent bottle.

[0010] Optionally, the second thread segment of the first screw is located above the first thread segment of the first screw; the upper end of the first channel is also provided with a powder return port corresponding to the second thread segment of the first screw, so as to allow the powder reagent accumulated in the first channel to leave the first channel and return to the reagent bottle under the transportation of the second thread segment of the first screw.

[0011] Optionally, the lowest position of the powder return port is not lower than the lowest position of the powder feed port.

[0012] Optionally, the distribution mechanism further includes a connecting channel adapted to connect the first channel and the second channel; the connecting channel extends obliquely downward from the first channel toward the second channel.

[0013] Optionally, a powder outlet is provided at the lower end of the second channel to allow the powder reagent in the second channel to be discharged outward under the transportation of the second screw; the dispensing mechanism also includes a clamp assembly suitable for opening and closing the powder outlet; the clamp assembly includes a pair of clamps arranged opposite to each other; the pair of clamps are respectively movably mounted on the outside of the second channel, and are suitable for being abutted to rotate outward to open the powder outlet, and to rotate inward to close to close the powder outlet after the abutment is released.

[0014] Optionally, the second screw has an opposite rotation direction to the first screw, and the thread of the second screw has an opposite rotation direction to the first thread segment of the first screw; or the second screw has the same rotation direction as the first screw, and the thread of the second screw has the same rotation direction as the first thread segment of the first screw.

[0015] Optionally, the dispensing mechanism also includes a screw drive mechanism suitable for driving the first screw and the second screw to rotate; the screw drive mechanism includes a first gear suitable for rotating, a second gear meshing with the first gear, and a planetary gear set connected to the first gear; the second gear is coaxially connected to the first screw to drive the first screw to rotate; the planetary gear set is connected to the second screw to drive the second screw to rotate.

[0016] Another aspect of the present invention is to provide a sample adding device, comprising the sample adder of the present invention and a weighing instrument used in conjunction with the sample adder; the weighing instrument is suitable for weighing the powder reagent output by the sample adder.

[0017] Compared with the prior art, the technical solution of the present invention has beneficial effects.

[0018] For example, the sampler of the present invention adopts two screws, wherein the first screw first performs powder feeding and powder returning operations simultaneously, and the second screw then performs powder discharge operation, which not only realizes high-precision powder discharge, but also avoids powder blockage caused by the backlog of powder reagents in the sampler during the powder discharge process, thereby ensuring the normal operation, working accuracy and working stability of the sampler and the sampler equipment; at the same time, since the first screw starts the powder returning operation while feeding powder, not only can the occurrence of powder blockage be solved at the source, but also the second screw can be made to only assume the function of powder discharge and its length can be shortened, thereby effectively reducing the volume of the entire sampler, so that the sampler occupies a small space, which is not only conducive to cost saving, but also more suitable for small-dose, high-precision powder discharge requirements.

[0019] For another example, the sample adder of the present invention sequentially conveys the powder reagent through the connected first channel and the second channel, and conveys the powder reagent outward through the powder outlet at the lower end of the second channel (if the powder outlet is set on the side of the channel, it will be inconvenient to convey the powder through the screw, and it will be difficult to control the output dosage of the powder). This makes it easy to control the size of the powder outlet, thereby making it easy to control the mass flow rate of the powder reagent output, thereby ensuring high-precision output of the powder reagent.

[0020] For another example, the sample injector of the present invention can simultaneously drive the first screw and the second screw to rotate through the screw drive mechanism, thereby saving a drive source while ensuring the normal operation of the first screw and the second screw, which is not only beneficial to saving costs but also saving occupied space. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 1 is a schematic structural diagram of a sample injector in a non-working state according to an embodiment of the present invention;

[0022] FIG2 is a cross-sectional view of the sample injector in a non-working state according to an embodiment of the present invention;

[0023] FIG3 is another cross-sectional view of the sample injector in a non-working state according to an embodiment of the present invention, wherein the threads of the first screw and the second screw are not shown;

[0024] 4 is a schematic structural diagram of the sample injector in a working state according to an embodiment of the present invention;

[0025] FIG5 is a cross-sectional view of the sample injector in a working state according to an embodiment of the present invention, wherein the threads of the first screw and the second screw are not shown;

[0026] FIG6 is a cross-sectional view of the sample adding device according to an embodiment of the present invention, wherein the threads of the first screw and the second screw are not shown.

[0027] Explanation of the accompanying drawings: 10 sampler, 11 shell, 12 bottle mouth sealing part, 13 sealing ring, 100 reagent bottle, 110 bottle mouth, 200 dispensing mechanism, 210 first channel, 211 powder inlet, 212 powder return port, 220 first screw, 221 first thread segment of first screw, 222 second thread segment of first screw, 230 second channel, 231 powder outlet, 240 second screw, 250 connecting channel, 261 first gear, 262 second gear, 263 transmission shaft, 264 third gear, 265 planetary carrier, 266 fourth gear, 270 clamp assembly, 271 first clamp, 272 second clamp, 273 torsion spring, 20 machine head. DETAILED DESCRIPTION

[0028] To make the objectives, features, and beneficial effects of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described below are intended only to illustrate the present invention and are not intended to limit the present invention. Furthermore, descriptions of identical or similar components between different embodiments, as well as descriptions of components, features, effects, and the like that are related to the prior art, may be omitted.

[0029] In addition, for the sake of ease of description, the drawings only show parts related to the present invention rather than all structures. In addition, the same or similar reference numerals may be used in the drawings to refer to the same or similar components in different embodiments.

[0030] 1 to 5 , an embodiment of the present invention provides a sample injector 10 .

[0031] Specifically, the injector 10 may include a housing 11, a reagent bottle 100 mounted on the housing 11, and a dispensing mechanism 200 sealedly connected to the reagent bottle 100. The reagent bottle 100 is suitable for storing a powdered reagent; the dispensing mechanism 200 is in communication with the reagent bottle 100 and is suitable for transferring the powdered reagent from the reagent bottle 100 to the outside, for example, to a test tube below the injector 10.

[0032] In a specific implementation, the dispensing mechanism 200 may include a first channel 210 communicating with the reagent bottle 100, a first screw 220 disposed in the first channel 210, a second channel 230 communicating with the first channel 210 in an upper and lower offset manner, and a second screw 240 disposed in the second channel 230. The first screw 220 is adapted to rotate and includes a first screw first thread segment 221 and a first screw second thread segment 222 of opposite rotation directions to transport the powdered reagent in the first channel 210 to the second channel 230 and the reagent bottle 100, respectively. The second screw 240 is also adapted to rotate to output the powdered reagent in the second channel 230 to the outside.

[0033] In a specific implementation, the reagent bottle 100 includes a bottle mouth 110 suitable for the powder reagent to enter and exit, and the bottle mouth 110 of the reagent bottle 100 is downwardly mounted on the housing 11. It can be understood that the downward herein may include inclined downward.

[0034] In some embodiments, the housing 11 is through-through from top to bottom and is adapted to partially accommodate the reagent bottle 100. In a specific implementation, the bottle mouth 110 of the reagent bottle 100 and a portion adjacent to the bottle mouth 110 are adapted to be accommodated within the housing 11.

[0035] In some embodiments, the housing 11 is further provided with a bottle mouth sealing portion 12 corresponding to the bottle mouth 110 of the reagent bottle 100. The bottle mouth sealing portion 12 extends along the outer peripheral side wall of the bottle mouth 110 to the end surface of the bottle mouth 110, then bends inward and fits against the inner peripheral side wall of the bottle mouth 110.

[0036] In some embodiments, a sealing ring 13 may be further provided between the end surface of the bottle mouth 110 and the bottle mouth sealing portion 12 to improve the sealing between the bottle mouth 110 and the housing 11 .

[0037] In some embodiments, the peripheral sidewall of the bottle mouth 110 of the reagent bottle 100 is further provided with a bottle mouth thread structure. Accordingly, the portion of the bottle mouth sealing portion 12 corresponding to the peripheral sidewall of the bottle mouth 110 is also provided with a mating thread structure adapted to the bottle mouth thread structure. The mating thread structure is threadedly connected to the bottle mouth thread structure to mount the reagent bottle 100 on the housing 11.

[0038] As previously mentioned, the first channel 210 and the second channel 230 of the dispensing mechanism 200 are connected in an upper and lower staggered manner. In a specific embodiment, the upper end of the first channel 210 can extend upward from the bottle mouth 110 of the reagent bottle 100 to the interior of the reagent bottle 100, and the outer side wall of the first channel 210 and the bottle mouth sealing portion 12 are tightly attached to the outer side of the inner circumference of the bottle mouth 100, so that the dispensing mechanism 200 is sealed and connected to the bottle mouth 110 of the reagent bottle 100 to prevent the powdered reagent in the reagent bottle 100 from leaking from the bottle mouth 110.

[0039] In some embodiments, the outer wall of the first channel 210 and the outer side of the bottle mouth sealing portion 12 that is attached to the inner circumference of the bottle mouth 100 are both made of plastic material to meet the sealing requirements.

[0040] In a specific implementation, a powder inlet 211 communicating with the reagent bottle 100 is provided at the upper end of the first channel 210 to receive the powder reagent from the reagent bottle 100 .

[0041] In some embodiments, the reagent bottle 100 is also adapted to rotate to facilitate delivery of the powdered reagent to the first channel 210. It is understood that, in a specific implementation, the sample injector 10 is adapted to be tilted obliquely downward so that the reagent bottle 100 is also tilted obliquely downward, which facilitates delivery of the powdered reagent in the reagent bottle 100 to the first channel 210 of the dispensing mechanism 200.

[0042] The first screw 220 is disposed within the first channel 210 and includes a first screw thread segment 221 and a first screw second thread segment 222, which rotate in opposite directions. The first screw second thread segment 222 is located above the first screw first thread segment 221. The first screw first thread segment 221 is adapted to transport the powdered reagent in the first channel 210 to the second channel 230 when the first screw 220 rotates. The first screw second thread segment 222 is adapted to return the powdered reagent in the first channel 210 to the reagent bottle 100 when the first screw 220 rotates.

[0043] It is understood that when the powdered reagent enters the first channel 220 from the reagent bottle 100 through the powder inlet 211, it may accumulate in the first channel 210 and thereby clog the threads of the first screw 220 and the gap between the first screw 220 and the inner wall of the first channel 210, thereby causing the dispensing mechanism 200 to malfunction. To this end, the present invention also provides a second thread segment 222 of the first screw adapted to transport excess accumulated powdered reagent in the first channel 210 back to the reagent bottle 100.

[0044] As mentioned above, the second thread segment 222 of the first screw is located above the first thread segment 221 of the first screw and rotates in the opposite direction to the first thread segment 221 of the first screw, so that while the first thread segment 221 of the first screw transports the powder reagent in the first channel 210 to the second channel 230, the excess powder reagent accumulated in the first channel 210 is returned to the reagent bottle 100. Accordingly, a powder return port 212 corresponding to the second thread segment 222 of the first screw is further provided at the upper end of the first channel 210, so as to allow the powder reagent accumulated in the first channel 210 to leave the first channel 210 and return to the reagent bottle 100 under the transport of the second thread segment 222 of the first screw.

[0045] In a specific implementation, the lowest position of the powder return port 212 is not lower than the lowest position of the powder inlet 211 , so that the powder reagent in the first channel 210 can be smoothly transported downward by the first thread segment 221 of the first screw.

[0046] It will be understood that the above “not less than” includes “higher than” and “equal to”.

[0047] As previously described, the first channel 210 and the second channel 230 of the dispensing mechanism 200 are connected in a vertically staggered manner. In a specific embodiment, the dispensing mechanism 200 further includes a connecting channel 250 adapted to connect the first channel 210 and the second channel 230. The connecting channel 250 extends obliquely downward from the first channel 210 toward the second channel 230, thereby facilitating the smooth transfer of the powdered reagent in the first channel 210 into the second channel 230.

[0048] In a specific implementation, both ends of the connecting channel 250 are connected to the lower side surface of the first channel 210 and the upper side surface of the second channel 230 respectively.

[0049] In some embodiments, the sample injector 10 further includes a screw driving mechanism adapted to drive the first screw 220 and the second screw 240 to rotate.

[0050] Specifically, the screw drive mechanism may include a first gear 261, a second gear 262, and a planetary gear set. The first gear 261 is adapted to be driven, for example, by a motor to rotate; the second gear 262 is meshed with the first gear 261 and coaxially connected to the first screw 220 to drive the first screw 220 to rotate when the first gear 261 rotates; and the planetary gear set is in driving connection with the second screw 240 to drive the second screw 240 to rotate.

[0051] In some embodiments, the planetary gear set may include a transmission shaft 263, a third gear 264, a planet carrier 265, and a fourth gear 266. The transmission shaft 263 is coaxially connected to the first gear 261 at one end and is adapted to rotate synchronously with the first gear 261 when the first gear 261 rotates; the third gear 264 is coaxially connected to the other end of the transmission shaft 263 and is adapted to rotate synchronously with the transmission shaft 263 when the transmission shaft 263 rotates; the planet carrier 265 has an inner gear ring meshing with the third gear 264 and the fourth gear 266, respectively; and the fourth gear 266 is coaxially connected to the second screw 240.

[0052] In a specific implementation, the first gear 261 rotates while driving the transmission shaft 263 to drive the third gear 264 to rotate; when the third gear 264 rotates, it drives the planetary carrier 265 to rotate; when the planetary carrier 265 rotates, it drives the fourth gear 266 to rotate; when the fourth gear 266 rotates, it drives the second screw 240 to rotate.

[0053] In this case, the first screw 220 and the second screw 240 can be driven to rotate simultaneously by the screw drive mechanism, thereby saving a driving source while ensuring the normal operation of the first screw 220 and the second screw 240, which is not only beneficial to saving costs but also saving occupied space.

[0054] In a specific implementation, when the size of the powder outlet 231 remains unchanged, the rotation speed of the first screw 220 and the second screw 240 can be controlled by the screw drive mechanism, and then the mass flow rate of the powder reagent output can be controlled by the rotation speed of the first screw 220 and the second screw 240, thereby ensuring high-precision output of the powder reagent.

[0055] As previously mentioned, in some embodiments, reagent bottle 100 is also suitable for rotation. In this case, the rotation of reagent bottle 100 can be independent of the rotation of the first screw rod 220 and the second screw rod 240, and reagent bottle rotation drive mechanism is set in addition. In specific implementation, reagent bottle rotation drive mechanism can adopt any known conventional technology means in this area to realize, is not limited here.

[0056] In a specific implementation, a powder outlet 231 communicating with the interior of the second channel 230 is provided at the lower end surface thereof, so as to allow the powder reagent in the second channel 230 to be discharged outward under the transportation of the second screw 240 .

[0057] In some embodiments, the second screw 240 rotates in the opposite direction to the first screw 220. In this case, the thread of the second screw 240 also rotates in the opposite direction to the thread of the first screw first thread segment 221. In this way, the powdered reagent can be transported downward in sequence through the first screw first thread segment 221 and the second screw 240.

[0058] In a specific implementation, the sample injector 10 further includes a clamp assembly 270 adapted to open and close the powder outlet 231 of the second channel 230 .

[0059] In some embodiments, the clamp assembly 270 includes a pair of clamps 271 and 272 disposed opposite to each other. Specifically, the pair of clamps 271 and 272 can be a first clamp 271 and a second clamp 272 , respectively. Furthermore, the first clamp 271 and the second clamp 272 are respectively installed on the outside of the second channel 230 .

[0060] In a specific implementation, the first clamp 271 and the second clamp 272 are rotatably mounted on two opposite portions of the outer side wall of the lower end of the second channel 230 .

[0061] In some embodiments, the first clamp 271 and the second clamp 272 can be respectively installed at two opposite parts of the lower outer side wall of the second channel 230 through a torsion spring 273 .

[0062] In a specific embodiment, when the first clamp 271 and the second clamp 272 are in an initial state, they can be closed to seal the powder outlet 231 of the second channel 230. During use, the torsion springs 273 connecting the first clamp 271 and the second clamp 272 are adapted to be abutted and twisted, respectively, to drive the first clamp 271 and the second clamp 272 connected thereto to rotate outward, respectively, to open the powder outlet 231. Furthermore, after the abutment is released, the two torsion springs 273 are adapted to restore the twisting, respectively, to drive the first clamp 271 and the second clamp 272 connected thereto to rotate inward, close, and reseal the powder outlet 231.

[0063] 6 , an embodiment of the present invention further provides a sample adding device including the sample adder 10 described above.

[0064] Specifically, the sample adding device may further include a head 20 suitable for mounting the sample adder 10, and a weighing instrument located below the head 20 and used in conjunction with the sample adder 10. The weighing instrument is suitable for weighing the powdered reagent output by the sample adder 10.

[0065] In some embodiments, the machine head 20 can be implemented by the machine head described in the patent document with publication number CN116295748A. Accordingly, a machine head lifting mechanism can also be provided to drive the machine head to rise and fall.

[0066] In a specific implementation, a test tube is suitable for being placed under the machine head 20 to receive the powder reagent output by the sample injector 10. The weighing instrument is suitable for weighing the powder reagent received in the test tube.

[0067] In some embodiments, the weighing instrument may be a high-precision analytical balance.

[0068] In a specific implementation, the implementation method of weighing the powder reagent received in the test tube by a weighing instrument can be achieved by any conventional technical means known in the art, which is not limited here.

[0069] As mentioned above, the sample injector 10 further includes a clamp assembly 270 adapted to open and close the powder outlet 231 of the second channel 230 , and the two torsion springs 273 in the clamp assembly 270 are adapted to be respectively abutted and twisted.

[0070] Correspondingly, the die head 20 is further provided with a housing chamber suitable for accommodating the injector 10 and a pair of abutment portions disposed within the housing chamber. When the injector 10 is inserted downwardly into the housing chamber, the two torsion springs 273 of the clamp assembly 270 are each abutted by one of the abutment portions, causing them to twist, thereby causing the first clamp 271 and the second clamp 272 to rotate outward, respectively, opening the powder outlet 231. Furthermore, when the injector 10 is removed from the housing chamber, the abutment is released, and the two torsion springs 273 are each capable of restoring the twisted state, thereby causing the first clamp 271 and the second clamp 272 to rotate inward and close, respectively, to re-close the powder outlet 231.

[0071] Although specific embodiments of the present invention have been described above, these embodiments are not intended to limit the scope of the present disclosure, even when only a single embodiment is described with respect to specific features. The feature examples provided in the present disclosure are intended to be illustrative rather than limiting, unless otherwise stated. In specific implementations, the technical features of one or more dependent claims may be combined with the technical features of the independent claim, depending on actual needs and where technically feasible, and the technical features of the corresponding claims may be combined in any appropriate manner rather than solely through the specific combinations listed in the claims.

[0072] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A sample dispenser (10), comprising a reagent bottle (100) suitable for storing a powder reagent and a dispensing mechanism (200) connected to the reagent bottle (100) and suitable for transporting the powder reagent out of the reagent bottle (100), characterized in that: The dispensing mechanism (200) comprises a first channel (210) connected to the reagent bottle (100), a first screw (220) arranged in the first channel (210), a second channel (230) connected to the first channel (210) in an up-down offset manner, and a second screw (240) arranged in the second channel (230); the first screw (220) is suitable for rotating and comprises a first screw first thread segment (221) and a first screw second thread segment (222) with opposite rotation directions to transport the powder reagent in the first channel (210) to the second channel (230) and the reagent bottle (100) respectively; the second screw (240) is also suitable for rotating to output the powder reagent in the second channel (230) to the outside.

2. The sample injector (10) according to claim 1, characterized in that: The reagent bottle (100) is suitable for rotating to facilitate conveying powder reagent to the first channel (210).

3. The sample injector (10) according to claim 1, characterized in that: The upper end of the first channel (210) extends into the reagent bottle (100), and is provided with a powder inlet (211) connected to the reagent bottle (100) to receive powder reagent from the reagent bottle (100).

4. The sample injector (10) according to claim 3, characterized in that: The second thread segment (222) of the first screw is located above the first thread segment (221) of the first screw; the upper end of the first channel (210) is also provided with a powder return port (212) corresponding to the second thread segment (222) of the first screw, so as to allow the powder reagent accumulated in the first channel (210) to leave the first channel (210) and return to the reagent bottle (100) under the transportation of the second thread segment (222) of the first screw.

5. The sample injector (10) according to claim 4, characterized in that: The lowest position of the powder return port (212) is not lower than the lowest position of the powder feed port (211).

6. The sample injector (10) according to claim 1, characterized in that: The distribution mechanism (200) further comprises a connecting channel (250) adapted to connect the first channel (210) and the second channel (230); the connecting channel (250) extends obliquely downward from the first channel (210) toward the second channel (230).

7. The sample injector (10) according to claim 1, characterized in that: A powder outlet (231) is provided at the lower end of the second channel (230) to allow the powder reagent in the second channel (230) to be discharged outward under the conveyance of the second screw (240); the dispensing mechanism (200) further comprises a clamp assembly (270) suitable for opening and closing the powder outlet (231); the clamp assembly (270) comprises a pair of clamps (271, 272) arranged opposite to each other; the pair of clamps (271, 272) are respectively movably mounted on the outer side of the second channel (230), and are suitable for being abutted to be respectively rotated outward to open the powder outlet (231), and respectively rotated inward to close to close the powder outlet (231) after the abutment is cancelled.

8. The sample injector (10) according to claim 1, characterized in that: The second screw (240) rotates in an opposite direction to the first screw (220), and the thread of the second screw (240) rotates in an opposite direction to the first thread segment (221) of the first screw; or The second screw (240) and the first screw (220) have the same rotation direction, and the thread of the second screw (240) and the first thread segment (221) of the first screw have the same rotation direction.

9. The sample injector (10) according to claim 1, characterized in that: The distribution mechanism (200) also includes a screw drive mechanism suitable for driving the first screw (220) and the second screw (240) to rotate; the screw drive mechanism includes a first gear (261) suitable for rotating, a second gear (262) meshing with the first gear (261), and a planetary gear set drivingly connected to the first gear (261); the second gear (262) is coaxially connected to the first screw (220) to drive the first screw (220) to rotate; the planetary gear set is drivingly connected to the second screw (240) to drive the second screw (240) to rotate.

10. A sample adding device, characterized in that: It comprises a sample adder (10) as described in any one of claims 1 to 9, and a weighing instrument used in conjunction with the sample adder (10); the weighing instrument is suitable for weighing the powder reagent output by the sample adder (10).

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