Fly ash sampling device and method for vertical flue

Abstract

The invention discloses a fly ash sampling device and method for a vertical flue, the device comprises a guide pipe, the end part of the guide pipe is communicated with a containing cavity, and the containing cavity is axially vertical to the guide pipe; the separation assembly is rotationally connected into the containing cavity and used for separating the flue gas from the fly ash; the conical ash falling pipe is arranged at the bottom of the accommodating cavity, and the bottom is connected with an ash collecting tank; the dust suction pipe is arranged at the bottom of the dust collection tank and communicated with the interior of the dust collection tank; the dust filtering piece is arranged between the dust collecting tank and the dust suction pipe; the reducing spray pipe is connected to one end, far away from the dust collection tank, of the dust suction pipe; wherein the end parts of the guide pipe and the tapered spray pipe face the incoming flow direction of the flue gas, when the flue gas flows into the guide pipe and the tapered spray pipe at the same time, the ash suction pipe generates negative pressure to suck and discharge the flue gas in the guide pipe, and fly ash in the flue gas falls into the ash collection tank, so that the problem that a traditional device is difficult to sample in a vertical flue is solved, and the sampling efficiency is improved. And the beneficial effect of efficiently and stably collecting the fly ash under the non-gravity auxiliary condition is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of flue gas monitoring and environmental protection testing equipment for thermal power plants, specifically relating to a fly ash sampling device and method for vertical flues. Background Technology

[0002] In the daily operation and maintenance and thermal performance testing of thermal power plants, fly ash sampling is an important means of evaluating combustion efficiency, boiler operating status, and pollutant emissions. Conventional fly ash sampling devices mostly adopt a vertical insertion method into the horizontal flue, utilizing the combined effect of flue gas flow direction and gravity to collect fly ash. Typically, dust-laden flue gas is introduced through an ash conveying pipe, and the fly ash settles into the ash collection tank by gravity to complete the sampling. This type of device has a simple structure, wide application, and is suitable for flue environments with appropriate horizontal sampling ports. However, in practical applications, some power plants lack usable horizontal flue sampling locations. When using vertical flues, traditional devices, inserted horizontally, cannot effectively utilize gravity for fly ash deposition, resulting in low sampling efficiency or even failure. Furthermore, existing devices rely on a single gravity settling mechanism, which is prone to fly ash re-emergence or escape under airflow disturbances, making it difficult to guarantee the representativeness and integrity of the samples. Summary of the Invention

[0003] The purpose of this invention is to provide a fly ash sampling device and method for vertical flues, in order to solve the technical defects of the prior art, which is difficult to collect fly ash and has low sampling efficiency due to the lack of gravity settling conditions in vertical flues.

[0004] To achieve the above objectives, this application provides the following technical solution: This application provides a fly ash sampling device for vertical flues, comprising: A guide tube, the end of which is connected to a receiving cavity, and the receiving cavity is axially perpendicular to the guide tube; The separation component is rotatably connected to the receiving cavity and is used to separate flue gas from fly ash; A conical ash discharge pipe is located at the bottom of the receiving cavity, and an ash collection tank is connected to its bottom; The suction pipe is located at the bottom of the ash collection tank and connects to the inside of the ash collection tank. The ash filter element is installed between the ash collection tank and the ash suction pipe; The converging nozzle is connected to the end of the suction pipe away from the ash collection tank. The ends of both the guide pipe and the converging nozzle face the direction of flue gas flow. When the flue gas flows into the guide pipe and the converging nozzle at the same time, the suction pipe generates a negative pressure to draw out the flue gas in the guide pipe and cause the fly ash in the flue gas to fall into the ash collection tank.

[0005] In one optional embodiment, the converging nozzle has a trumpet-shaped structure, with the small end of the converging nozzle connected to the ash suction pipe and the large end facing the direction of flue gas flow.

[0006] In one alternative embodiment, the suction pipe and the tapered nozzle are axially aligned and axially perpendicular to the ash collection tank.

[0007] In one alternative embodiment, both the tapered ash discharge pipe and the ash collection tank are tapered pipes, with the smaller port of the tapered ash discharge pipe connected to the larger port of the ash collection tank.

[0008] In one alternative embodiment, the tapered ash discharge pipe and the ash collection tank are axially aligned.

[0009] In one alternative embodiment, the filter element is detachably connected between the ash collection tank and the ash suction pipe.

[0010] In one alternative embodiment, the filter element is fixed between the ash collection tank and the ash suction pipe by screws.

[0011] In one alternative embodiment, the filter element is a filter screen.

[0012] In one optional embodiment, the receiving cavity has an annular structure, and the separation component includes: a rotating shaft, which is rotatably connected to the receiving cavity and axially coincides with the receiving cavity; Multiple blades are located on the outside of the rotating shaft.

[0013] A second aspect of this application provides a method for sampling fly ash in a vertical flue, the method being performed using any of the aforementioned fly ash sampling devices, comprising: Orient the ends of the guide tube and the converging nozzle toward the direction of flue gas flow so that the flue gas flows into the guide tube and the converging nozzle simultaneously. The separation assembly connected in the containment cavity separates the flue gas and fly ash flowing into the guide pipe. At the same time, the suction pipe generates negative pressure through the tapered nozzle to draw out the separated flue gas in the guide pipe. Meanwhile, the separated fly ash falls into the ash collection tank through the conical ash drop pipe at the bottom of the containment cavity. The fly ash is collected in the ash collection tank by using the filter element between the ash collection tank and the ash suction pipe. Compared with the prior art, the present invention has the following beneficial effects: Because of the axially vertically connected guide tube and receiving cavity, and the formation of a negative pressure suction channel at the bottom consisting of a suction pipe and a gradually narrowing nozzle arranged in the windward direction, the high-speed flue gas flows through the gradually narrowing nozzle and generates a Bernoulli effect, creating a negative pressure in the suction pipe. This actively draws in the upper flue gas, overcoming the defect that gravity settling cannot be relied upon in vertical flues. At the same time, the combination of rotating separation components and filter elements enables multi-stage fly ash collection, improving sampling efficiency and representativeness. This solves the problem of difficult sampling in vertical flues with traditional devices, achieving the beneficial effect of efficient and stable fly ash collection under gravity-free conditions. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A schematic diagram of a fly ash sampling device for a vertical flue provided by the present invention; In the diagram: 1. Guide tube; 2. Separation component; 3. Conical ash drop pipe; 4. Ash collection tank; 5. Ash filter; 6. Converging nozzle; 7. Ash suction pipe. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0018] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0019] To address the technical deficiencies mentioned in the background section, this embodiment provides a fly ash sampling device and method for vertical flues.

[0020] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1As shown, in a first aspect of the present invention, a fly ash sampling device for a vertical flue is provided, comprising: a guide pipe 1, the end of which is connected to a receiving cavity, the receiving cavity being axially perpendicular to the guide pipe 1; a separation component 2, rotatably connected to the receiving cavity, for separating flue gas from fly ash; a conical ash-falling pipe 3, disposed at the bottom of the receiving cavity, the bottom of which is connected to an ash collection tank 4; an ash-suction pipe 7, disposed at the bottom of the ash collection tank 4 and communicating with the interior of the ash collection tank 4; a filter element 5, disposed between the ash collection tank 4 and the ash-suction pipe 7; and a tapered nozzle 6, connected to the end of the ash-suction pipe 7 away from the ash collection tank 4; wherein the ends of the guide pipe 1 and the tapered nozzle 6 are both oriented towards the flue gas flow direction, and when the flue gas flows simultaneously into the guide pipe 1 and the tapered nozzle 6, the ash-suction pipe 7 generates a negative pressure to draw out the flue gas in the guide pipe 1 and cause the fly ash in the flue gas to fall into the ash collection tank 4.

[0021] The guide tube 1 serves as the inlet channel for dust-laden flue gas, with its end facing the direction of flue gas flow. It can efficiently capture high-speed flowing dust-laden flue gas. The guide tube 1 is axially and vertically connected to the receiving cavity, allowing the entire device to extend into the vertical flue in a horizontal posture. This adapts to different flue layouts and, in particular, solves the problem that traditional vertical sampling devices cannot utilize gravity settling in vertical flues.

[0022] The receiving cavity is located downstream of and connected to the guide tube 1. It is used to receive the flue gas flow field entering from the guide tube 1 and to provide installation space for the separation component 2. The receiving cavity can be a ring structure or other adaptable shape. A certain buffer area is formed inside, which helps to reduce the flue gas flow rate and guide the airflow to smoothly transition to the subsequent components.

[0023] The separation component 2 is rotatably connected to the receiving cavity and can rotate or maintain a preset speed under the impact of flue gas, thereby achieving preliminary separation of flue gas and fly ash particles using centrifugal force and collision interception mechanism. For example, the separation component 2 may include multiple blades fixed on a rotating shaft. When flue gas impacts the surface of the blades, larger fly ash particles are derailed due to inertia and slide down the blade surface into the lower channel, while the purified flue gas continues to flow upward or circumferentially.

[0024] The conical ash discharge pipe 3 is located at the bottom of the receiving cavity to receive the fly ash separated by the separation component 2 and guide it to the ash collection tank 4. This conical structure helps to reduce dead corners of fly ash accumulation and improve the smoothness of ash discharge.

[0025] The ash collection tank 4 is connected to the bottom of the conical ash discharge pipe 3 to form the final storage unit for fly ash. Its volume can be flexibly designed according to the sampling cycle and dust concentration. The ash suction pipe 7 is set at the bottom of the ash collection tank 4 and communicates with the inside. As part of the negative pressure suction path, its function is to form a local low pressure zone under specific aerodynamic conditions, thereby driving the upper flue gas to flow downward.

[0026] The filter element 5 is located between the ash collection tank 4 and the ash suction pipe 7. It is mainly used to prevent the collected fly ash from being carried out by the reverse airflow, while allowing the gas to pass through smoothly. The filter element 5 can be made of porous materials, such as metal mesh, ceramic filter element or fiber fabric, etc., and has certain mechanical strength and high temperature resistance, making it suitable for long-term operation in flue gas environment.

[0027] The converging nozzle 6 is connected to the end of the suction pipe 7 away from the ash collection tank 4. The whole has a pipe structure with a gradually decreasing cross-section. Its small end is connected to the suction pipe 7, and its large end faces the direction of flue gas flow. When the high-speed flue gas from the outside flows into the converging nozzle 6, according to Bernoulli's principle, the fluid velocity increases and the static pressure decreases in the channel contraction area, thereby generating a negative pressure inside the suction pipe 7. This negative pressure is transmitted to the vicinity of the outlet of the upper guide pipe 1 through the connecting path, forming a suction force from top to bottom, which causes the flue gas that has completed solid-gas separation in the guide pipe 1 to be continuously extracted and discharged from the system through the bottom.

[0028] During implementation, the guide pipe 1 and the converging nozzle 6 serve as two independent air intake channels, both facing the direction of flue gas flow, ensuring that they simultaneously draw in high-speed flue gas; the negative pressure generated by the converging nozzle 6 acts in the opposite direction to the outlet area of ​​the guide pipe 1 through the path of ash suction pipe 7—ash filter 5—ash collection tank 4—conical ash drop pipe 3—accommodating cavity—guide pipe 1, forming a suction airflow circuit that runs through the entire device.

[0029] During this process, the fly ash is initially captured at the separation component 2 and falls naturally. It enters the ash collection tank 4 through the conical ash drop pipe 3 and is blocked and retained by the ash filter element 5, while the clean flue gas is drawn downward by negative pressure and discharged, thus completing the sampling process.

[0030] Through the above technical solution, a fly ash collection mechanism that can efficiently sample in a vertical flue without external power has been realized. Since the guide tube 1 is perpendicular to the axial direction of the receiving cavity, the device can be horizontally inserted into the vertical flue, breaking through the limitation of the installation direction of the traditional sampling method. At the same time, by utilizing the kinetic energy of the high-speed flue gas on site, negative pressure is induced at the converging nozzle 6 to drive the airflow circulation of the entire system, which significantly enhances the fly ash collection capacity.

[0031] In this embodiment, the converging nozzle 6 has a trumpet-shaped structure. The small end of the converging nozzle 6 is connected to the ash suction pipe 7, and the large end faces the direction of flue gas flow.

[0032] The structure of the tapered nozzle 6 is described in detail. The tapered nozzle 6 is shaped like a trumpet that gradually narrows axially. Its inlet end (large end) has a large windward area to efficiently capture the high-speed flue gas flowing in the flue. The outlet end (small end) is connected to the ash suction pipe 7 to form a continuously variable cross-section guide channel. This trumpet-shaped structure achieves a continuous reduction in the flow cross-sectional area through a smoothly transitioned inner wall curved surface or conical surface, so that the gas entering the nozzle gradually increases in velocity during the flow process. According to Bernoulli's principle, the increase in flow velocity leads to a decrease in static pressure, thereby forming a stable negative pressure zone in the connection area of ​​the ash suction pipe 7. This negative pressure effect is transmitted to the inside of the ash collection tank 4 through the ash suction pipe 7 and extends upward to affect the airflow environment near the outlet of the guide pipe 1, thereby driving the separated flue gas to be drawn out from top to bottom.

[0033] The horn-shaped structure can be designed with a conical, Laval-type front converging section or a streamlined profile, and its expansion angle can be selected between 10° and 60° to balance intake efficiency and pressure gradient establishment.

[0034] For example, in one alternative embodiment, the tapered nozzle 6 is made of metal (such as stainless steel 304) with a corrosion-resistant surface, making it suitable for high-temperature corrosive flue gas environments; in another embodiment, it can also be injection molded from engineering plastics (such as polytetrafluoroethylene PTFE) to reduce weight and improve chemical resistance, making it particularly suitable for low-temperature flue gas sampling scenarios.

[0035] In addition, the large end opening of the horn-shaped structure can be fitted with a protective mesh or guide fins to prevent foreign objects from entering while improving air intake uniformity.

[0036] The larger end of the converging nozzle 6 faces the direction of the flue gas flow, ensuring that external flue gas can smoothly enter the nozzle and avoid airflow separation and vortex loss caused by reverse installation. Its axis is consistent with the mainstream direction of the flue gas, and the installation angle deviation is controlled within ±5° to maximize the utilization of flue gas kinetic energy. The connection between the smaller end and the suction pipe 7 can be a threaded connection, flange connection, or welded seal to ensure the airtightness and mechanical stability of the gas connection.

[0037] In actual arrangement, the converging nozzle 6 and the suction pipe 7 are kept axially aligned, so that the airflow accelerates smoothly along the centerline and reduces local resistance loss.

[0038] When high-speed flue gas flows into the large end of the converging nozzle 6 in the flue, the gas is accelerated and a low-pressure area is formed near the small end outlet due to the gradually narrowing flow area. This low pressure is transmitted to the lower part of the ash collection tank 4 through the ash suction pipe 7 and forms a pressure difference with the airflow in the upper guide pipe 1, which causes the separated flue gas to flow downward and complete the suction action. This process does not rely on an external power source and fully utilizes the airflow energy of the flue itself to achieve negative pressure suction, which has the advantages of energy saving, reliability and maintenance-free operation.

[0039] Through the above technical solution, the larger end faces the direction of flue gas flow, and the smaller end connects to the ash suction pipe 7, thereby effectively guiding the high-speed external flue gas into the system and accelerating its flow, forming a significant and stable negative pressure zone at the connection point of the ash suction pipe 7. This structure enhances the continuity of air intake and the efficiency of flow rate improvement, thereby increasing the negative pressure generation capacity of the entire fly ash sampling device. This, in turn, strengthens the suction effect on the flue gas in the guide pipe 1, promoting the settling of fly ash particles into the ash collection tank 4. It solves the problem that traditional sampling devices struggle to effectively collect fly ash in vertical flues by gravity, especially in applications where the device extends horizontally into a vertical flue. The active negative pressure drainage compensates for the unfavorable influence of gravity, improving sampling efficiency and representativeness.

[0040] In this embodiment, the suction pipe 7 and the converging nozzle 6 are axially aligned and perpendicular to the ash collection tank 4. The suction pipe 7 and the converging nozzle 6 are axially aligned, and their central axes are on the same straight line. This ensures that the high-speed flue gas flowing in from the converging nozzle 6 can enter the suction pipe 7 without deflection, reducing flow separation, vortex formation and energy loss caused by sudden changes in airflow direction. This helps maintain a stable negative pressure conduction path and improves the transmission efficiency of suction power.

[0041] Meanwhile, the suction pipe 7 and the ash collection tank 4 are connected by an axial vertical connection, that is, the axis of the suction pipe 7 and the axis of the ash collection tank 4 form a 90° angle, so that the suction pipe 7 is connected from the bottom or side of the ash collection tank 4, which avoids the fly ash from directly impacting the inlet area of ​​the suction pipe 7 during the fall, reduces the risk of blockage, and helps the fly ash to settle evenly in the ash collection tank 4, maintaining the stability of the internal static pressure.

[0042] Furthermore, the design of the axial overlap between the suction pipe 7 and the converging nozzle 6 can be applied to different diameter matching scenarios. For example, when the inner diameter of the outlet end of the converging nozzle 6 is smaller than the inner diameter of the suction pipe 7, a smooth diameter expansion connection can be achieved through the transition section; conversely, it allows the pipe diameter to be adjusted within a certain range to adapt to the on-site installation conditions or flow requirements.

[0043] In addition, the axial alignment structure facilitates assembly and positioning, improves the overall structural consistency and sealing reliability of the equipment. As for the vertical connection between the suction pipe 7 and the ash collection tank 4, the interface position can be adjusted according to the specific shape of the ash collection tank 4, such as setting it on the side or bottom side wall of the extension section of the conical ash drop pipe 3, as long as it meets the requirements of fluid conduction and does not interfere with the natural falling of fly ash.

[0044] In an optional embodiment, a flange or quick-connect fitting may be added to the connection between the suction pipe 7 and the ash collection tank 4 to facilitate disassembly, maintenance, and replacement of the filter element 5.

[0045] Through the above technical solution, this application achieves a straightened airflow path between the suction pipe 7 and the converging nozzle 6, reducing flow resistance and turbulence disturbance, and improving the efficiency of negative pressure generation and conduction. Simultaneously, the vertical connection between the suction pipe 7 and the ash collection tank 4 avoids direct impact of fly ash particles on the suction channel, reducing the probability of blockage and ensuring the continuity and stability of the sampling process. Therefore, even in a vertical flue environment lacking gravity-assisted settling conditions, the device can still achieve reliable fly ash collection through its optimized flow channel structure, solving the problem of low sampling efficiency in non-horizontally arranged flues using traditional sampling devices.

[0046] In this scheme, both the conical ash discharge pipe 3 and the ash collection tank 4 are tapered pipes. The small port of the conical ash discharge pipe 3 is connected to the large port of the ash collection tank 4, forming a continuously contracting flow channel. This optimizes the downward path of fly ash under the combined action of gravity and airflow, which not only improves the efficiency of fly ash transfer from the separation area to the collection area, but also enhances the internal negative pressure gradient with the help of aerodynamic effect, promotes stable settling of fly ash, and avoids secondary lifting or stagnation and blockage.

[0047] Among them, the conical ash discharge pipe 3 refers to an ash guiding channel whose cross-sectional area gradually decreases along the axial direction. It is usually set at the bottom of the receiving cavity to guide the fly ash after being processed by the separation component 2 to be transported downward. The pipe can be conical, square conical or polygonal tapering structure. The material can be stainless steel, carbon steel or high temperature resistant alloy to adapt to the high temperature and corrosive environment in the flue. Its tilt angle can be adjusted according to the actual working conditions, generally controlled between 30° and 75° to ensure that the fly ash slides smoothly under the action of gravity.

[0048] As an optional embodiment, the inner wall of the conical ash discharge pipe 3 can be polished or coated with an anti-stick coating (such as Teflon) to reduce the risk of fly ash adhesion; a rapping device can also be added to the outside of the pipe to periodically remove accumulated ash and ensure smooth long-term operation.

[0049] The ash collection tank 4 is a sealed container used to store collected fly ash. It is located at the bottom of the device and is directly connected to the conical ash discharge pipe 3. It is also a tapered pipe structure, that is, a conical container that is larger at the top and smaller at the bottom. This is conducive to concentrating fly ash and reducing the size of the bottom outlet, which facilitates subsequent sampling operations.

[0050] The ash collection tank 4 can be designed as a split unit, consisting of an upper flared section and a lower narrowed section, which are connected by flanges or threads for easy disassembly and cleaning. Its volume is set according to the expected sampling time and the dust concentration in the flue gas, and is usually between 0.5L and 5L.

[0051] To improve sealing performance, a sealing gasket is provided at the connection between the ash collection tank 4 and the conical ash discharge pipe 3 to prevent outside air from seeping in or fly ash from leaking.

[0052] In this embodiment, the conical ash discharge pipe 3 and the ash collection tank 4 are axially aligned, ensuring that the fly ash can fall smoothly along the central axis after separation, avoiding fly ash accumulation, airflow turbulence or local blockage caused by eccentric connection, improving the continuity and stability of material transmission inside the sampling device, especially in vertical flue application scenarios, effectively making up for the shortcomings of low efficiency of traditional gravity settling.

[0053] The ash collection tank 4 is a container used to collect and temporarily store fly ash. It is located at the downstream end of the conical ash collection pipe 3. Its inlet end is connected to the small port of the conical ash collection pipe 3. The ash collection tank 4 is usually a closed or semi-closed structure with a certain volume to hold a certain amount of fly ash sample for subsequent sampling and analysis. Its material must also have high temperature resistance and corrosion resistance. It can also be designed as a detachable structure according to the usage requirements for easy cleaning and replacement.

[0054] As an optional embodiment, the connection between the conical ash pipe 3 and the ash collection tank 4 can be achieved by a flange and a sealing ring. The bolt holes on the flange are evenly distributed around the circumference to ensure easy alignment and axial consistency during installation. Alternatively, a locating pin structure can be set to assist alignment and improve assembly accuracy.

[0055] Furthermore, in some variant designs, the conical ash discharge pipe 3 and the ash collection tank 4 can be manufactured as a single piece, fundamentally eliminating the possibility of assembly deviations and further improving the reliability of the system. After the fly ash is separated from the flue gas by the separation component 2 in the receiving cavity, it immediately enters the conical ash discharge pipe 3 and moves downward under the combined action of gravity and downward airflow. Since the conical ash discharge pipe 3 and the ash collection tank 4 are axially aligned, the fly ash particles fall smoothly into the ash collection tank 4 along the central axis without deflection or collision with the side walls, thus ensuring the continuity and efficiency of the ash discharge process.

[0056] Through the above technical solution, this application achieves coaxial alignment of the conical ash drop pipe 3 and the ash collection tank 4 in spatial arrangement. Due to the existence of this axially overlapping structure, the fly ash has the shortest path and the least resistance during the falling process, avoiding the problems of edge accumulation and poor flow. This solves the technical problem of difficulty in effectively using gravity to collect fly ash in vertical flues, improves the stability of the sampling device operation and the maintenance cycle interval, and achieves the technical effect of improving sampling efficiency and reliability.

[0057] In this embodiment, the filter element 5 is detachably connected between the ash collection tank 4 and the ash suction pipe 7. By setting the filter element 5 to a detachable connection, the filter element 5 can be easily removed from the connection position between the ash collection tank 4 and the ash suction pipe 7, thereby facilitating the regular cleaning, replacement or maintenance of the filter element 5, improving the overall operational flexibility and maintainability of the device, and is especially suitable for application scenarios where fly ash accumulates a lot and the ash filtration efficiency decreases during long-term operation.

[0058] Among them, the filter element 5 refers to the filter structure used to intercept and retain fly ash particles while allowing flue gas to pass through. Its function is to prevent fly ash from entering the downstream system of the suction pipe 7 with the airflow during the negative pressure suction process, and to ensure that the fly ash is stably deposited in the ash collection tank 4. The filter element 5 can be made of materials with high temperature resistance and corrosion resistance, such as metal mesh, ceramic porous body, sintered metal fiber or multi-layer stainless steel wire mesh, and can maintain structural integrity and filtration performance in high temperature flue gas environment.

[0059] The overall shape of the filter element 5 can be designed as round, square or other suitable shapes according to the interface shape between the ash collection tank 4 and the ash suction pipe 7. Its size should match the connection part to achieve sealed installation and avoid gas short circuit or fly ash leakage.

[0060] Detachable connection refers to the connection method between the filter element 5 and the ash collection tank 4 and the ash suction pipe 7, which allows for repeated assembly and disassembly without damaging the main structure. Common implementation forms include, but are not limited to, threaded connection, snap-fit ​​connection, flange connection, quick-release clamp connection, etc.

[0061] For example, in one optional embodiment, the filter element 5 is provided with external threads on its outer periphery, and the inner wall of the bottom outlet of the ash collection tank 4 is provided with corresponding internal threads, and a fixed seal is achieved by screwing them together; in another embodiment, the filter element 5 is placed between two flanges and is detachably connected by bolts. This type of connection not only ensures the structural sealing, but also supports quick disassembly and assembly by manual or tool assistance, and is suitable for frequent on-site maintenance operations.

[0062] In actual use, when the negative pressure in the suction pipe 7 decreases, the airflow resistance increases, or the sampling efficiency decreases, it can be determined that the filter element 5 may be blocked. At this time, the sampling operation can be stopped, the filter element 5 can be completely removed, and it can be purged, cleaned, or replaced directly with a new filter element 5. After that, it can be reinstalled to restore the normal operation of the device. This process does not require disassembling the entire sampling device, which significantly reduces the maintenance difficulty and downtime.

[0063] In this embodiment, the filter element 5 is fixed between the ash collection tank 4 and the ash suction pipe 7 by screws. The filter element 5 is a filter screen, which is a filter medium with a regular pore structure. It is set in the connection area between the ash collection tank 4 and the ash suction pipe 7 to intercept fly ash particles when the airflow passes through, while allowing the purified flue gas to be discharged smoothly. The filter screen can be made of metal (such as stainless steel wire mesh, nickel-based alloy mesh) or high-temperature resistant non-metallic material (such as ceramic fiber woven mesh), which has good thermal stability and mechanical strength and can operate stably for a long time in a high-temperature flue gas environment.

[0064] The pore size range of the filter screen can be selected according to the actual fly ash particle size distribution, usually set between 10μm and 150μm, in order to effectively block most fly ash particles, while avoiding excessive pressure drop due to excessively fine pores, which would affect the negative pressure suction efficiency. Its structure can be single-layer or multi-layer stacked, and can also be designed as cylindrical, flat or conical, flexibly adapted according to the installation space and airflow direction.

[0065] As an alternative embodiment, the filter screen can be replaced with a sintered porous metal plate or a honeycomb ceramic filter element, which can also achieve efficient interception of fly ash and has higher structural rigidity and anti-clogging ability. In another variant, an electrostatic deposition device can be used to replace the physical filter screen. An electric field is applied in the airflow channel to charge the fly ash and adsorb it onto the electrode plate, thereby achieving unobstructed sampling, which is suitable for continuous sampling needs under specific high dust concentration conditions.

[0066] The filter screen is located at the outlet end of the ash collection tank 4, at the end of the fly ash settling path. Upstream of it is a gravity separation zone formed by the receiving cavity and the conical ash discharge pipe 3, and downstream it connects to the negative pressure suction system formed by the ash suction pipe 7 and the tapered nozzle 6. When the flue gas carries fine fly ash particles down to the bottom of the ash collection tank 4, the filter screen forms the last barrier, preventing the fly ash from escaping with the airflow and ensuring that the sample is completely retained in the ash collection tank 4. This structure, combined with a detachable connection method (such as fixing with screws), facilitates regular disassembly, cleaning, or replacement, maintaining the reliability and consistency of long-term sampling by the device.

[0067] By implementing the above technical solutions, the filter element 5 is concretized into a filter screen, which effectively traps fly ash particles of different sizes using its physical sieving mechanism, ensuring the particle retention rate during the sampling process. At the same time, thanks to the mature manufacturing process and diversified structural options, the adaptability and maintenance convenience of the device in complex flue gas environments are improved, thereby optimizing the integrity of fly ash collection and the sustainability of operation without changing the overall device layout.

[0068] In this embodiment, the receiving cavity is an annular structure. The separation component 2 includes a rotating shaft that is rotatably connected to the receiving cavity and axially coincides with the receiving cavity. Multiple blades are disposed on the outside of the rotating shaft. By setting an annular receiving cavity and arranging the rotating separation component 2, which consists of the rotating shaft and the outer blades, and making the rotating shaft axially coincide with the receiving cavity, efficient centrifugal separation of the dust-laden flue gas entering the guide pipe 1 can be achieved.

[0069] This structure utilizes the rotational motion generated by the impact of flue gas on the blades to create a centrifugal force field, causing fly ash particles to gather and fall towards the outer wall, while the purified flue gas flows along the central area, facilitating subsequent negative pressure suction and discharge, thus improving the overall separation efficiency of fly ash and flue gas.

[0070] The receiving cavity has an annular structure, with a cross-section that can be circular or square. Inside, it forms an annular space surrounding the central axis, used to accommodate and guide the operation of the rotating components. This annular design not only provides sufficient radial space for the installation of the shaft and blades but also ensures that the airflow is evenly distributed around the blades after entering, avoiding the generation of localized vortices or dead zones. A certain distance is maintained between the inner and outer walls of the annular structure to accommodate the blade's rotation radius and to reserve necessary sealing and support structures.

[0071] In a second aspect, the present invention provides a method for sampling fly ash in a vertical flue, which is performed using the aforementioned fly ash sampling device for a vertical flue. The sampling device includes a guide pipe 1, a receiving cavity, a separation component 2, a conical ash collection pipe 3, an ash collection tank 4, an ash suction pipe 7, a filter element 5, and a tapered nozzle 6.

[0072] One end of the guide pipe 1 is exposed inside the flue and faces the direction of flue gas flow, while the other end is connected to the annular receiving cavity. The two are axially perpendicular, forming a lateral air intake channel. A separation component 2 is rotatably connected inside the receiving cavity. This component can be a multi-bladed structure that rotates around an axis, used to apply centrifugal force to the incoming flue gas to achieve gas-solid separation. A conical ash collection pipe 3 is connected to the bottom of the receiving cavity, which further connects to the ash collection tank 4, forming a fly ash downward channel. The bottom of the ash collection tank 4 is equipped with a suction pipe 7, and a filter element 5 is installed between the suction pipe 7 and the ash collection tank 4 to prevent fly ash particles from escaping with the airflow. The end of the suction pipe 7 furthest from the ash collection tank 4 is connected to a converging nozzle 6. This nozzle is trumpet-shaped, with its smaller end connected to the suction pipe 7 and its larger end facing the direction of flue gas flow. The entire system requires no external fan or power supply, relying entirely on the kinetic energy of the mainstream flue gas within the flue to generate a negative pressure effect to complete the sampling cycle.

[0073] Step 1: Orient the ends of the guide pipe 1 and the converging nozzle 6 toward the direction of flue gas flow so that the flue gas flows into the guide pipe 1 and the converging nozzle 6 at the same time; wherein, the guide pipe 1 and the converging nozzle 6 are both arranged in the windward position, that is, their open end faces are directly facing the direction of flue gas flow, to ensure that the mainstream flue gas can enter the two pipes simultaneously.

[0074] As the main inlet for carrying ash and flue gas, the cross-sectional shape of the guide pipe 1 can be designed as circular, square or other adaptable forms according to the actual flue size. It can be selected as a rectangle or rounded rectangle that matches the flue wall to reduce turbulence.

[0075] The converging nozzle 6 constitutes a negative pressure generating unit. Its large-diameter end receives high-speed flue gas, and the flow velocity increases as it flows through the gradually narrowing inner cavity. Based on the Venturi effect, a local low-pressure zone is generated in the throat area, which is then transmitted to the ash collection tank 4 and the upper space through the ash suction pipe 7.

[0076] The parallel arrangement of the two pipes facing the wind allows the same mainstream flue gas to serve as both a sampling source and a driving source, achieving self-sufficiency in energy. This arrangement is particularly suitable for horizontal installations in vertical flues, where the direction of gravity is not the same as the direction of fly ash movement, and pneumatic suction is needed to compensate for insufficient gravity.

[0077] As an optional embodiment, when applied to a horizontal flue, the entire device can be inserted vertically, while the guide pipe 1 and the converging nozzle 6 are still facing the wind together. At this time, the fly ash settles faster under the dual action of gravity and negative pressure, increasing the sampling amount per unit time.

[0078] As another variant, the guide tube 1 and the tapered nozzle 6 can share the same housing and be separated into independent channels by an internal partition to simplify the structure and enhance anti-interference capabilities.

[0079] Step Two: Simultaneously, the flue gas flowing into the guide pipe 1 is separated from the fly ash by the rotating separation component 2 within the receiving cavity. At the same time, a negative pressure is generated in the suction pipe 7 via the converging nozzle 6 to draw out the separated flue gas from the guide pipe 1. Simultaneously, the separated fly ash falls into the ash collection tank 4 through the conical ash drop pipe 3 at the bottom of the receiving cavity. The separation component 2 includes a rotating shaft and multiple blades fixed to its outer periphery, forming a turbine-like or spiral guide structure. When the ash-laden flue gas enters the receiving cavity tangentially or axially from the guide pipe 1, it impacts the blade surface and propels it to rotate. Simultaneously, the flue gas moves outward under centrifugal force, while the denser fly ash particles are thrown against the inner wall of the cavity due to inertia and slide down the conical ash drop pipe 3 below.

[0080] Meanwhile, the high-speed flue gas flowing in the converging nozzle 6 forms a low-pressure zone at its outlet end. This negative pressure is transmitted to the inside of the ash collection tank 4 through the ash suction pipe 7 and extends upwards to affect the bottom area of ​​the receiving cavity, forming a top-down suction airflow path. This suction force causes the clean flue gas, which has had most of the fly ash removed, to flow downwards from the end of the guide pipe 1 through the central area of ​​the receiving cavity, and finally to be discharged downstream of the flue or to the emission system through the ash suction pipe 7. Thus, the separation process and the suction process are carried out simultaneously, forming a continuous and stable sampling flow field. It is worth noting that the parameters such as the number of blades, inclination angle, and curvature of the separation component 2 can be optimized according to the flue gas velocity range. For example, fewer blades and a larger inclination angle can be used to reduce resistance under high flow velocity conditions, while the number of blades can be increased to improve separation efficiency under low flow velocity conditions. The rotating shaft can be freely rotated through a bearing structure, or a damping device can be configured to prevent resonance. Both the conical ash discharge pipe 3 and the ash collection tank 4 are designed with a converging structure, which helps to concentrate the fly ash flow direction and reduce dead angles, improving the smoothness of ash discharge.

[0081] Step 3: The fly ash is trapped in the ash collection tank 4 by the filter element 5 between the ash collection tank 4 and the ash suction pipe 7, thus completing the fly ash sampling. The filter element 5 is set in the flow path between the ash collection tank 4 and the ash suction pipe 7, and is mainly used to intercept fine fly ash particles that may escape with the downward airflow, ensuring the integrity of the sample.

[0082] The filter element 5 can be made of metal mesh or sintered porous material, possessing certain mechanical strength and high temperature resistance, and can operate for a long time in environments above 300℃; the filter mesh pore size is selected according to the target fly ash particle size distribution, and is generally controlled within the range of 10~100μm, which can effectively filter particles without clogging too quickly.

[0083] The filter element 5 is detachable, for example, fixed by flanges, clamps or screws, which facilitates regular cleaning or replacement.

[0084] In some embodiments, the filter element 5 can also be replaced by a cyclone pre-separator or an electrostatic deposition unit to meet the sampling requirements of fly ash with different particle sizes or compositions.

[0085] Through the above-described steps, this application realizes a passive fly ash sampling method driven by flue gas kinetic energy. Since the guide pipe 1 and the converging nozzle 6 are arranged synchronously facing the wind, the energy of the mainstream flue gas is fully utilized to generate negative pressure suction, replacing the traditional power source that relies on an external fan. Combined with the centrifugal separation effect of the rotating separation component 2 and the end interception function of the filter element 5, a multi-level collaborative collection mechanism of "primary centrifugal separation - gravity-assisted sedimentation - negative pressure guided conveying - terminal filtration retention" is formed. This method not only solves the problem of sampling difficulties caused by unfavorable gravity direction in vertical flues, but also significantly improves sampling efficiency and representativeness. It is particularly suitable for industrial sites with limited space, no power supply, or frequent maintenance. The whole process requires no additional energy consumption, is reliable in operation, has strong compatibility, and can be adapted to the fly ash monitoring needs of various furnace types and combustion conditions.

[0086] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fly ash sampling device for vertical flues, characterized in that, include: A guide tube, the end of which is connected to a receiving cavity, the receiving cavity being axially perpendicular to the guide tube; The separation component is rotatably connected to the receiving cavity and is used to separate flue gas from fly ash; A conical ash discharge pipe is located at the bottom of the receiving cavity, and an ash collection tank is connected to its bottom; A suction pipe is installed at the bottom of the ash collection tank and communicates with the inside of the ash collection tank. A filter element is installed between the ash collection tank and the ash suction pipe; The converging nozzle is connected to the end of the suction pipe furthest from the ash collection tank; The ends of the guide pipe and the converging nozzle are both oriented towards the direction of flue gas flow. When the flue gas flows into the guide pipe and the converging nozzle at the same time, the ash suction pipe generates negative pressure to draw out the flue gas in the guide pipe and cause the fly ash in the flue gas to fall into the ash collection tank.

2. The fly ash sampling device for a vertical flue according to claim 1, characterized in that, The converging nozzle has a trumpet-shaped structure, with its small end connected to the ash suction pipe and its large end facing the direction of flue gas flow.

3. The fly ash sampling device for a vertical flue according to claim 2, characterized in that, The suction pipe and the tapering nozzle are axially aligned and perpendicular to the ash collection tank.

4. A fly ash sampling device for a vertical flue according to claim 1, characterized in that, Both the conical ash discharge pipe and the ash collection tank are tapered pipes, and the small port of the conical ash discharge pipe is connected to the large port of the ash collection tank.

5. A fly ash sampling device for a vertical flue according to claim 1 or 4, characterized in that, The conical ash discharge pipe and the ash collection tank are axially aligned.

6. A fly ash sampling device for a vertical flue according to claim 1, characterized in that, The filter element is detachably connected between the ash collection tank and the ash suction pipe.

7. A fly ash sampling device for a vertical flue according to claim 6, characterized in that, The filter element is fixed between the ash collection tank and the ash suction pipe by screws.

8. A fly ash sampling device for a vertical flue according to claim 1, 6, or 7, characterized in that, The filter element is a filter screen.

9. A fly ash sampling device for a vertical flue according to claim 1, characterized in that, The receiving cavity has an annular structure, and the separation component includes: The rotating shaft is rotatably connected to the receiving cavity and is axially aligned with the receiving cavity. Multiple blades are disposed on the outside of the rotating shaft.

10. A method for sampling fly ash in vertical flues, characterized in that, The method is performed using a fly ash sampling device for vertical flues as described in any one of claims 1-9, comprising: Orient the ends of the guide tube and the converging nozzle toward the direction of flue gas flow so that the flue gas flows into the guide tube and the converging nozzle simultaneously. The flue gas flowing into the guide pipe is separated from the fly ash by the rotating separation component in the receiving cavity. At the same time, the suction pipe is negatively pressured by the tapered nozzle to draw out the separated flue gas in the guide pipe. Meanwhile, the separated fly ash falls into the ash collection tank through the conical ash drop pipe at the bottom of the receiving cavity. The fly ash is collected in the ash collection tank by using the filter element between the ash collection tank and the ash suction pipe, thus completing the fly ash sampling.

Images