Sample preparation device for detecting content of heavy metals in sludge

Abstract

The invention discloses a sample preparation device for detecting the content of heavy metals in sludge, and belongs to the technical field of sludge detection. The sample preparation device comprises a dewatering part, a filtering part and a compacting part which are sequentially arranged, the dewatering part is provided with a dewatering cavity, the dewatering part comprises a feeding port and a discharging port which are formed in the upper end and the lower end of the dewatering part respectively and communicated with the dewatering cavity, a grinding part is arranged in the dewatering cavity, and the grinding part stirs and / or grinds sludge in the dewatering cavity; the filtering piece is used for filtering the ground sludge in the dewatering cavity. The dewatering piece, the filtering piece and the compacting piece are arranged to dope a certain proportion of heat conducting agent into the sludge sample to be detected, and meanwhile, the sludge sample can meet the drying requirement and the density is more uniform and compact, so that the sensitivity of LIBS signal detection and the strength and stability of spectral signals are improved.

Description

Technical Field

[0001] The invention relates to the technical field of sludge detection, and more specifically to a sample preparation device for detecting heavy metal content in sludge. Background Art

[0002] Laser induced breakdown spectroscopy (LIBS) technology, its basic principle is to use high-energy laser to act on the surface of the sample to be tested through an optical system. After the sample absorbs energy, it instantly vaporizes to produce high-temperature, high-density plasma. During the cooling process, the plasma releases a radiation spectrum containing sample component information. The spectral signal is received using lenses and optical fibers, and the data is transmitted to the computer for analysis after conversion by the spectrometer. LIBS technology has the advantages of instant analysis and simultaneous measurement of multiple heavy metal elements.

[0003] Since sludge is a complex matrix, different types of sludge have different matrices. Even if the concentration of heavy metal elements is the same, the intensity of its characteristic spectrum will be different. In order to overcome this matrix effect of sludge, many scholars at home and abroad have studied a variety of treatment methods, such as adding adhesives, covering glass sheets on the sample, etc. These methods are to change the matrix properties of the sample to reduce the influence of the matrix effect. Sludge has a low melting point (generally 1400-2000℃) and poor thermal conductivity. When the laser pulse acts on the surface, it does not fully absorb the laser pulse energy. Evenly adding a thermal conductor with a low boiling point to the sludge makes it easier to absorb the laser pulse energy and then transfer it to the sludge particles, so that the sludge sample is heated more evenly, the efficiency of the sludge particles absorbing the laser pulse energy is improved, and the amount of sludge ablation is increased. Chloride salts of light metals have a low melting point, are inexpensive, and are non-toxic, and can be used as additives. However, substances such as MgCl2 and CaCl2 have strong water absorption in the air and cannot be added to the sample. Therefore, there is a related technology that evenly adds NaCl to the sludge sample to reduce or overcome the matrix effect, while improving the ablation efficiency and enhancing the plasma spectrum.

[0004] At present, the LIBS technology for detecting heavy metals in sludge has the following defects:

[0005] (1) Studies have shown that sample humidity has a significant impact on the intensity and stability of plasma spectra. Under the same sample preparation conditions, the higher the water content, the smaller the spectral intensity and the worse the stability. When the sample humidity is greater than a certain value, the sample is soft and difficult to shape, and cannot be detected by LIBS. At the same time, when the sample humidity is high, the water in the sample will absorb a large amount of laser pulse energy and produce a water vapor environment atmosphere on the sample surface, which has a strong shielding effect on the plasma, resulting in very weak and unstable plasma spectrum intensity. After deep dehydration, the water content of sewage plant sludge is between 55% and 65%, and it cannot be directly detected using LIBS technology. Excessive water content in the sample seriously affects the sensitivity of spectral signal detection;

[0006] (2) When the laser pulse acts directly on the sample surface, it will stir up a lot of dust. At the same time, due to the uneven density of the sample, the amount of sample ablated by the laser pulse will vary greatly, causing the plasma spectrum signal to be unstable. The dust will also hinder the lens from receiving the soil plasma spectrum signal. At present, the uneven density of sludge in the measurement process causes a large difference in spectral intensity, thus affecting the accuracy and stability of the LIBS measurement results.

[0007] For example, the Chinese patent: An online detection system and method for heavy metals in drainage pipe sludge (publication number CN109520974B) discloses an online detection system and method for heavy metals in drainage pipe sludge, which includes a sludge pretreatment device and a detection device; the sludge pretreatment device can screen out impurities from the extracted sludge, and the stirring module and the spraying module can ensure that the heavy metal elements in the sludge to be tested are evenly distributed and can improve the repeatability of the detection, reduce the detection limit of the elements, and improve the sensitivity of the elements to be tested. The invention combines laser induced breakdown spectroscopy technology with spraying and other technologies to achieve online detection of heavy metal elements in drainage pipe sludge. Spraying technology is used to make samples. However, the unevenness of the samples being tested leads to deviations in the final results, which is a problem that needs to be solved urgently. Summary of the invention

[0008] The content of this application is used to introduce concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of this application is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0009] Some embodiments of the present application propose a sample preparation device for detecting heavy metal content in sludge to solve the technical problems mentioned in the above background technology section.

[0010] As a first aspect of the present application, some embodiments of the present application provide a sample preparation device for detecting heavy metal content in sludge, comprising a dehydration component, a filter component and a compaction component, wherein the dehydration component, the filter component and the compaction component are arranged in sequence, the dehydration component has a dehydration chamber, the dehydration component comprises a feed port and a discharge port, the feed port and the discharge port are respectively arranged at the upper end and the lower end of the dehydration component and are connected to the dehydration chamber, a grinding part is provided in the dehydration chamber, and the grinding part stirs and\or grinds the sludge in the dehydration chamber;

[0011] The filter element is used to filter the ground sludge in the dehydration chamber, and the filter element includes a filter portion, which is arranged at one end of the discharge port of the dehydration element. The filter portion is inclined so that the height of the first end of the filter portion is higher than the height of the second end, and the first end of the filter portion is close to the discharge port.

[0012] Furthermore, the filter element includes a slag discharge portion, and the slag discharge portion is arranged at the second end of the filter portion.

[0013] Furthermore, the filter element comprises a shell, and the slag discharge portion is a window arranged on the shell.

[0014] Furthermore, the height difference between the first end and the second end of the filter portion is L, and the value range of L is 5 cm to 10 cm.

[0015] Furthermore, the grinding part comprises a rotating shaft, and the rotating shaft is provided with a stirring blade;

[0016] Among them, the rotating shaft is provided with an air supply pipe, the stirring blade is provided with an air outlet channel, the air outlet channel is connected to the air supply pipe, the air supply pipe is connected to an external air source, and the dehydration component is provided with an exhaust hole so that the water vapor in the dehydration chamber can be discharged from the dehydration chamber.

[0017] Furthermore, the diameter of the gas outlet channel close to the discharge port is smaller than the diameter of the gas outlet channel close to the feed port.

[0018] Furthermore, a weight sensor is provided in the dehydration element near the discharge port.

[0019] Furthermore, the compacting member includes a driving part, a guide part and a sample slot, the driving part is connected to a compacting rod, the compacting rod is driven by the driving part and moves along the length direction of the guide channel, and the sample slot is arranged at the lower part of the guide channel.

[0020] Furthermore, the guide part includes a first guide cavity and a second guide cavity, the first guide cavity and the second guide cavity are connected and the first guide cavity is arranged at the upper part of the second guide cavity, the upper end opening of the first guide cavity is arranged at the lower end of the filter part, and the lower part of the second guide cavity is connected to the guide channel.

[0021] Furthermore, the first flow guide cavity includes a first flow guide platform, and the angle between the inclined surface of the first flow guide platform and the horizontal plane ranges from 60° to 85°.

[0022] Furthermore, the second flow guide cavity includes a second flow guide platform, and the angle between the inclined surface of the second flow guide platform and the horizontal plane ranges from 45° to 70°.

[0023] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0024] (1) The present invention provides a dehydration component to enable the sludge sample to meet the drying requirements. Compared with before treatment, the moisture content of the sample to be tested can be reduced to below 6%, and the temperature of the formed plasma is increased to about 7000K, which can effectively enhance the intensity of spectral signal reception.

[0025] (2) The present invention can reduce the influence of the soil matrix effect by uniformly doping a certain proportion of NaCl powder as a thermal conductor in the dehydration element, while improving the soil ablation efficiency and enhancing the soil plasma spectrum. Compared with before treatment, the spectral intensity of the element to be measured is enhanced by 1-4 times, and the sensitivity of signal detection is also significantly improved.

[0026] (3) The present invention provides a filter and a compactor so that the sludge sample to be tested filtered by the filter can be pressed more tightly and with more uniform density by the compactor, so that under the action of the laser pulse, only a pit is generated on the surface of the sample without generating a large amount of dust, so that the intensity and stability of the plasma spectrum signal are significantly improved. Compared with before the treatment, the relative standard deviation (RSD) of the intensity of the heavy metal characteristic spectral line of the sample to be tested is less than 5%. At the same time, by tilting the filter part of the filter, the filter itself will not be blocked, and the speed of preparing samples is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The illustrative embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application.

[0028] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the components and elements are not necessarily drawn to scale.

[0029] Figure 1 It is a schematic diagram of the overall structure of a sample preparation device for detecting heavy metal content in sludge according to an embodiment of the present application;

[0030] Figure 2 It is a schematic structural diagram of a grinding part of a sample preparation device for detecting heavy metal content in sludge according to an embodiment of the present application;

[0031] Figure 3 It is a schematic diagram of the angular structure of the guide part of the sample preparation device for detecting the heavy metal content in sludge according to an embodiment of the present application.

[0032] Explanation of the symbols in the schematic diagram:

[0033] 100, dehydration element; 110, dehydration chamber; 120, feed port; 130, discharge port; 140, grinding part; 141, rotating shaft; 1411, air supply pipeline; 142, stirring blade; 1421, air outlet channel; 150, heat transfer agent feed port;

[0034] 200, filter element; 210, filter portion; 220, slag discharge portion; 230, housing;

[0035] 300, compacting member; 310, driving unit; 320, flow guide unit; 321, first flow guide cavity; 322, second flow guide cavity; 323, first flow guide platform; 324, second flow guide platform; 330, sample slot; 340, compacting rod. DETAILED DESCRIPTION

[0036] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0037] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0038] It should be noted that the concepts such as "first" and "second" mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0039] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0040] The names of the messages or information exchanged between multiple devices in the embodiments of the present disclosure are only used for illustrative purposes and are not used to limit the scope of these messages or information.

[0041] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0042] like Figures 1 to 3 As shown, a sample preparation device for detecting heavy metal content in sludge according to an embodiment of the present application comprises a dehydration member 100, a filter member 200 and a compaction member 300, wherein the dehydration member 100, the filter member 200 and the compaction member 300 are arranged in sequence, the dehydration member 100 has a dehydration chamber 110, the dehydration member 100 comprises a feed port 120 and a discharge port 130, the feed port 120 and the discharge port 130 are respectively arranged at the upper end and the lower end of the dehydration member 100 and communicated with the dehydration chamber 110, a grinding part 140 is provided in the dehydration chamber 110, and the grinding part 140 stirs and\or grinds the sludge in the dehydration chamber 110;

[0043] The filter element 200 is used to filter the ground sludge in the dehydration chamber 110, and the filter element 200 includes a filter portion 210, and the filter portion 210 is arranged at one end of the discharge port 130 of the dehydration element 100. The filter portion 210 is inclined so that the height of the first end of the filter portion 210 is higher than the height of the second end, and the first end of the filter portion 210 is close to the discharge port 130.

[0044] Specifically, the dehydration component 100 is arranged at the uppermost end of the sample preparation device. The sludge after preliminary treatment is first dehydrated and ground by the dehydration component 100. The dehydration component 100 is provided with a feed port 120 and a discharge port 130. The sludge sample enters the dehydration chamber 110 from the feed port 120. An electric control valve is provided on the feed port 120. A fixed amount of sludge sample is fed into the feed port 120 each time. A heat conductive agent feed port (150) is also provided on one side of the feed port 120 for adding a heat conductive agent (NaCl powder) so that the doping ratio of the heat conductive agent can be precisely controlled. The sludge sample is dehydrated by the dehydration part 100, and the sludge in the dehydration process is stirred and ground by the grinding part 140. The grinding part 140 can turn the large pieces of sludge sample into powder by beating and cutting. The powdered sludge sample is then discharged from the dehydration chamber 110 through the discharge port 130 and enters the next step for preparation. Among them, an electric valve is provided in the discharge port 130, which can control the opening and closing of the discharge port 130.

[0045] The powdered sludge sample discharged from the discharge port 130 enters the filter element 200 for filtration. The filter element 200 includes a filter section 210. The filter section 210 is a sieve with a plurality of small holes of equal diameter. The filter section 210 can screen the powdered sludge sample. Powders smaller than the diameter of the sieve holes of the filter section 210 can be filtered out from the filter section 210 and enter the subsequent preparation steps. Powders larger than the diameter of the sieve holes of the filter section 210 cannot be filtered out from the filter section 210 and remain above the filter section 210, and eventually need to be removed manually.

[0046] Among them, the sample particle size is another important factor affecting the LIBS spectrum. The smaller the particle size, the better the sample uniformity, and its LIBS spectrum can more effectively reflect the elemental composition and content information of the sludge. The larger the particle size, the more the texture, morphology, structure and other information of the sludge itself are retained, and the LIBS spectrum cannot effectively reflect the information of the entire sample. A large number of experiments have shown that the particle size-mass distribution after grinding is: 56% below 50μm; 60% below 60μm; 63% below 70μm; 67% below 80μm; 69% below 90μm; 72% below 100μm; 74% below 110μm; 77% below 120μm; 78% below 130μm; 79% below 140μm; 80% below 150μm. The sieve of the filter 210 is set to 100 mesh (150μm), which can fully utilize the sample while meeting the accuracy of the heavy metal spectrum detection of the sludge sample.

[0047] The filter 210 is tilted, and the two sides of the filter 210 are defined as the first end and the second end, respectively. The height of the first end of the filter 210 is higher than the height of the second end and the first end is close to the discharge port 130. The powdered sludge discharged from the discharge port 130 enters the filter element 200 for filtration. After being discharged from the discharge port 130, it first contacts the first end of the filter 210. Since the height of the first end is greater than the height of the second end, the powder rolls from the first end to the second end under the action of gravity. During the rolling process, powder smaller than the diameter of the mesh of the filter 210 can be filtered out of the filter 210, and powder larger than the diameter of the mesh of the filter 210 cannot be filtered out of the filter 210 and remains above the filter 210. The height difference between the first end and the second end of the filter 210 is L. The value range of L is 5 cm to 10 cm, and specifically L is 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, and 10 cm. The value range of L is 5 cm to 10 cm, which can ensure that the powder can roll on the filter part 210 by its own gravity and also ensure that the powder will not roll too fast on the filter part 210, thereby achieving a better filtering effect.

[0048] The filter section 210 is tilted, which makes it less likely for the filter section 210 to be clogged than a horizontally disposed filter section 210, because during the screening process, the powdered sludge is subjected to the squeezing force of other powders on its sides in addition to its own gravity, thereby reducing the probability of being stuck in the filter holes of the filter section 210, thereby making the filter section 210 less likely to be clogged, thereby increasing the manufacturing efficiency of the entire product.

[0049] In a specific embodiment, the filter element 200 includes a slag discharge portion 220, and the slag discharge portion 220 is disposed at the second end of the filter element 210. The filter element 200 includes a housing 230, and the slag discharge portion 220 is a window disposed on the housing 230. The slag discharge portion 220 is disposed at a position where the second end of the filter element 210 contacts the housing 230 of the filter element 200, and the slag discharge portion 220 discharges the sludge powder that cannot be filtered from the filter element 210 from the entire preparation device. There is no need for manual slag discharge, which avoids the accumulation of slag materials and thus affects the filtering effect of the filter element 210.

[0050] In a specific embodiment, the grinding part 140 includes a rotating shaft 141, and a stirring blade 142 is provided on the rotating shaft 141; wherein, an air supply pipe 1411 is provided in the rotating shaft 141, and an air outlet channel 1421 is provided on the stirring blade 142, wherein the air outlet channel 1421 is connected to the air supply pipe 1411, and the air supply pipe 1411 is connected to an external air source, and the dehydration component 100 is provided with an exhaust hole so that the water vapor in the dehydration chamber 110 can be discharged from the dehydration chamber 110.

[0051] Specifically, the rotating shaft 141 of the grinding part 140 is driven by a driving motor, and it can rotate at a set speed. A stirring blade 142 is provided on the outer wall of the rotating shaft 141. The conveying direction of the stirring blade 142 is opposite to the direction of gravity. Therefore, when the sludge enters the dewatering chamber 110 and is contacted by the stirring blade 142, the sludge moves in the direction of gravity under the action of gravity. The conveying direction of the stirring blade 142 is opposite to the direction of gravity. Therefore, the sludge can be bounced away after contacting the stirring blade 142, so that the sludge can move more paths in the dewatering part 100 and the drying effect can be better. At the same time, the stirring blade 142 can also cut the lumps of sludge so that the sludge is quickly decomposed into small particles. The overall surface area of ​​the sludge is increased, so it can be dried more thoroughly. Through a large number of experiments, it is concluded that for sludge with a moisture content of about 60%, after dehydration by crushing and heating: the moisture content is about 55% after 1 minute; the moisture content is about 51% after 2 minutes; the moisture content is about 45% after 3 minutes; the moisture content is about 38% after 4 minutes; the moisture content is about 30% after 5 minutes; the moisture content is about 20% after 6 minutes; the moisture content is about 14% after 7 minutes; the moisture content is about 11% after 8 minutes; the moisture content is about 8% after 9 minutes; the moisture content is about 6% after 10 minutes; the spectral detection requirements can be met after 10 minutes of dehydration.

[0052] More specifically, the rotating shaft 141 is provided with an air supply pipe 1411, and the air supply pipe 1411 is connected to an external air source, that is, one end of the air supply pipe 1411 extends from one end of the rotating shaft 141 into the interior thereof, and the other end is connected to an external air source, and the external air source delivers high-temperature inert gas to the dehydration chamber 110 through the air supply pipe 1411, and the stirring blade 142 is provided with an air outlet channel 1421 connected to the air supply pipe 1411, and the high-temperature inert gas of the external air source is delivered to the dehydration chamber 110 from the air outlet channel 1421. Among them, the external air source includes an air source bottle, and the external air source is an inert gas such as nitrogen, and the air source bottle is connected to the air supply pipe 1411 through a pipe, and a heating wire is also provided on the pipe for heating the gas in the pipe to a specified temperature.

[0053] More specifically, an exhaust hole is provided at the upper end of the dehydration element 100, and the exhaust hole is used to discharge the gas in the dehydration chamber 110. The exhaust hole is provided at the upper part of the dehydration element 100. A gas-solid separator is provided in the exhaust hole.

[0054] The exhaust hole is arranged at the upper part of the dehydration component 100, and the exhaust hole is connected to the inside of the dehydration chamber 110 to discharge the excess inert gas in the dehydration chamber 110 and the water vapor separated from the sludge into the dehydration chamber 110. In order to prevent the dried sludge powder from being discharged from the exhaust hole along with the inert gas and the water vapor separated from the sludge and then clogging the exhaust hole, a gas-solid separator is arranged at the exhaust hole, which can smoothly discharge the inert gas and the water vapor separated from the sludge out of the dehydration chamber 110.

[0055] In a specific embodiment, the diameter of the air outlet channel 1421 near the discharge port 130 is smaller than the diameter of the air outlet channel 1421 near the feed port 120. Specifically, the air outlet channel 1421 provided on the stirring blade 142 is provided with a one-way valve, that is, the gas can be transported from the air supply pipe 1411 to the dehydration chamber 110, but cannot be transported from the dehydration chamber 110 to the air supply pipe 1411, and in order to ensure that the stirring blade 142 can dry the sludge at various locations, the diameter of the air outlet channel 1421 near the discharge port 130 is smaller than the diameter of the air outlet channel 1421 near the feed port 120. According to the Bernoulli principle, the impact force of the wind blown out from the air outlet channel 1421 near the feed port 120 is the largest, so that the sludge just entering the dehydration chamber 110 can be fully blown away for rapid dehydration and drying.

[0056] In a specific embodiment, a weight sensor (not shown in the figure) is also provided near the discharge port 130. The weight sensor can detect the weight of the sludge before and after dehydration and the weight after doping with the thermal conductor, thereby regulating the sludge moisture content and the thermal conductor doping ratio.

[0057] In a specific embodiment, the compacting member 300 includes a driving part 310, a guide part 320 and a sample slot 330. The driving part 310 is connected to a compacting rod 340. The compacting rod 340 is driven by the driving part 310 and moves along the length direction of the guide channel. The sample slot 330 is arranged at the lower part of the guide channel.

[0058] Specifically, the driving unit 310 drives the compaction rod 340 to move along the guide part 320. The guide part 320 is set as a channel along the direction of gravity. A sample slot 330 is provided below the guide part 320. The driving unit 310 can be specifically an electric cylinder or a gas cylinder, which drives the telescopic rod to move. The compaction rod 340 is connected to one end of the driving unit 310 of the telescopic rod principle. By controlling the pressure applied by the electric cylinder or the gas cylinder, a soil piece with consistent density, compactness and firmness can be obtained for subsequent testing. In a feasible scheme, the sample slot 330 is a cylindrical slot body with a diameter of 3 cm and a height of 5 mm. A plurality of sample slots 330 can be provided, and a plurality of sample slots 330 are moved to the bottom of the guide channel in turn for tableting. A pressure sensing device is provided at the bottom of the sample slot 330. By controlling the pressure parameters, the density of the prepared sludge sample is kept consistent, thereby solving the error problem caused by inconsistent sample density.

[0059] More specifically, the guide portion 320 includes a first guide cavity 321 and a second guide cavity 322, the first guide cavity 321 and the second guide cavity 322 are connected, and the first guide cavity 321 is arranged at the upper part of the second guide cavity 322, the upper end opening of the first guide cavity 321 is arranged at the lower end of the filter portion 210, and the lower part of the second guide cavity 322 is connected to the guide channel. The first guide cavity 321 includes a first guide platform 323, and the angle between the inclined surface of the first guide platform 323 and the horizontal plane ranges from 60° to 85°. The second guide cavity 322 includes a second guide platform 324, and the angle between the inclined surface of the second guide platform 324 and the horizontal plane ranges from 45° to 70°.

[0060] The first guide chamber 321 and the second guide chamber 322 are connected to each other. The powdered sludge filtered from the filter element 200 passes through the first guide chamber 321 and the second guide chamber 322 in sequence to reach the guide channel, and then is pressed into the sample tank 330 by the compacting rod 340. The first guide platform 323 of the first guide chamber 321 has an inclined surface, and the angle between the inclined surface and the horizontal plane is in the range of 60° to 85°, specifically 60°, 65°, 70°, 75°, 80° and 85°, that is, after the powdered sludge falls on the first guide platform 323, it can contact the inclined surface of the first guide platform 323, and then the powdered sludge slides down the inclined surface of the first guide platform 323 into the second guide chamber 322 by gravity, and the upper end of the second guide chamber 322 is aligned with the first guide chamber 321. The second guide chamber 322 is connected to the lower end of the second guide chamber 322, and the second guide platform 324 has an inclined surface, and the angle between the inclined surface and the horizontal plane is in the range of 45° to 70°, and specifically can be 45°, 50°, 55°, 60°, 65°, 70°. The powder sliding down from the first guide platform 323 falls into the second guide chamber 322, and then is guided by the second guide platform 324 in the second guide chamber 322, so that the powder can just fall into the guide channel, and finally fall into the sample tank 330. The angle of the inclined surface of the first guide platform 323 is relatively large, which can enable the powder sludge falling on the first guide platform 323 to quickly fall from the first guide platform 323 to the second guide platform 324, and the angle of the inclined surface of the second guide platform 324 is relatively small, in order to prevent the powder from falling into the sample tank 330 too fast and causing dust.

[0061] The above descriptions are only some preferred embodiments of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with the technical features disclosed in the embodiments of the present disclosure but are not limited to those with similar functions to form a technical solution.

Claims

1. A sample preparation device for detecting heavy metal content in sludge, characterized in that: The invention comprises a dewatering element (100), a filtering element (200) and a compacting element (300), wherein the dewatering element (100), the filtering element (200) and the compacting element (300) are arranged in sequence, the dewatering element (100) has a dewatering chamber (110), the dewatering element (100) comprises a feed inlet (120) and a discharge outlet (130), the feed inlet (120) and the discharge outlet (130) are respectively arranged at the upper end and the lower end of the dewatering element (100) and communicated with the dewatering chamber (110), the dewatering chamber (110) is provided with a grinding part (140), and the grinding part (140) stirs and / or grinds the sludge in the dewatering chamber (110); The filter element (200) is used to filter the ground sludge in the dewatering chamber (110), and the filter element (200) comprises a filter portion (210), and the filter portion (210) is arranged at one end of the discharge port (130) of the dewatering element (100), and the filter portion (210) is inclined so that the height of the first end of the filter portion (210) is higher than the height of the second end, and the first end of the filter portion (210) is close to the discharge port (130).

2. The sample preparation device for detecting heavy metal content in sludge according to claim 1, characterized in that: The filter element (200) comprises a slag discharge portion (220), and the slag discharge portion (220) is arranged at the second end of the filter portion (210).

3. The sample preparation device for detecting heavy metal content in sludge according to claim 2, characterized in that: The filter element (200) comprises a shell (230), and the slag discharge portion (220) is a window arranged on the shell (230).

4. The sample preparation device for detecting heavy metal content in sludge according to any one of claims 1 to 3, characterized in that: The height difference between the first end and the second end of the filter portion (210) is L, and the value range of L is 5 cm to 10 cm.

5. The sample preparation device for detecting heavy metal content in sludge according to claim 4, characterized in that: The grinding part (140) comprises a rotating shaft (141), and a stirring blade (142) is provided on the rotating shaft (141); The rotating shaft (141) is provided with an air supply pipe (1411), the stirring blade (142) is provided with an air outlet channel (1421), the air outlet channel (1421) is connected to the air supply pipe (1411), the air supply pipe (1411) is connected to an external air source, and the dehydration element (100) is provided with an exhaust hole so that water vapor in the dehydration chamber (110) can be discharged from the dehydration chamber (110).

6. The sample preparation device for detecting heavy metal content in sludge according to claim 5, characterized in that: The diameter of the gas outlet channel (1421) close to the material outlet (130) is smaller than the diameter of the gas outlet channel (1421) close to the material inlet (120).

7. The sample preparation device for detecting heavy metal content in sludge according to claim 4, characterized in that: A weight sensor is also provided in the dehydration element near the discharge port.

8. The sample preparation device for detecting heavy metal content in sludge according to claim 4, characterized in that: The compacting member (300) comprises a driving portion (310), a flow guiding portion (320) and a sample slot (330); the driving portion (310) is connected to a compacting rod (340); the compacting rod (340) is driven by the driving portion (310) and moves along the length direction of the flow guiding channel; the sample slot (330) is arranged at the lower part of the flow guiding channel.

9. The sample preparation device for detecting heavy metal content in sludge according to claim 8, characterized in that: The guide portion (320) comprises a first guide cavity (321) and a second guide cavity (322); the first guide cavity (321) and the second guide cavity (322) are connected and the first guide cavity (321) is arranged at the upper part of the second guide cavity (322); the upper end opening of the first guide cavity (321) is arranged at the lower end of the filter portion (210); and the lower part of the second guide cavity (322) is connected to the guide channel.

10. The sample preparation device for detecting heavy metal content in sludge according to claim 9, characterized in that: The first flow guiding cavity (321) comprises a first flow guiding platform (323), and the angle between the inclined surface of the first flow guiding platform (323) and the horizontal plane ranges from 60° to 85°.

11. The sample preparation device for detecting heavy metal content in sludge according to claim 10, characterized in that: The second flow guiding cavity (322) comprises a second flow guiding platform (324), and the angle between the inclined surface of the second flow guiding platform (324) and the horizontal plane ranges from 45° to 70°.

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