CN102921635A - Screw air elutriation fine-coal remover for dry classification before fine coal preparation - Google Patents

Abstract

The invention belongs to the technical field of fines removal classification before coal preparation and particularly relates to a screw air elutriation fine-coal remover for dry classification before fine coal preparation. The fine-coal remover comprises a primary classification region which uses a spiral airflow conveying method and a secondary classification region which uses a tangential airflow jetting rotating classification method. During the declining process, materials are subjected to the comprehensive action of spiral centrifugal force and airflow conveying force, intensifying classification is obtained under the comprehensive action, primary fine materials which are subjected to primary classification enter the secondary classification region, are subjected to secondary classification and are discharged, downward negative pressure is introduced into the secondary classification region, and materials can be discharged smoothly when large classification grain sizes are required. By the aid of the fine-coal remover, the problem of blocking of screening holes is solved, the classification grain sizes can be adjusted and controlled at will in a range from 0 to 13 mm in accordance with requirements, and a new technology is provided for power coal fines removing and washing.

Description

A spiral air screen dedusting machine for dry classification before fine-grained coal selection

technical field

The invention belongs to the technical field of powder removal and classification before coal washing, and in particular relates to a spiral air screen powder removal machine used for dry classification before fine coal separation.

Background technique

my country is rich in steam coal resources, but because my country's steam coal is mainly distributed in the north and west, this geographical distribution determines the coal transportation and sales structure of "north coal transportation" and "west coal transportation" in my country, while China's coal However, there is a shortage of transportation capacity in transportation. With the construction and development of large-scale pithead power stations in my country, it has become an inevitable trend to switch from coal transportation to electricity transmission.

With the improvement of coal mining mechanization, the content of pulverized coal in raw coal has greatly increased, and the content of fine coal with a particle size of less than 13mm is sometimes as high as 70% to 80%, and most of the coal types are low-modified bituminous coal (long-flame coal, non-caking coal, Weakly sticky coal, 1/2 medium sticky coal), the biggest feature of low metamorphic bituminous coal in my country is low ash and low sulfur, and the average ash content of raw coal can reach below 15%. Therefore, if it can be directly separated and used as coal for power generation in pithead power plants , will greatly save transport capacity to alleviate the problem of insufficient transport capacity, and at the same time indirectly increase the proportion of lump coal selected.

At the same time, in coal washing and selection, if the fine-grained coal is selected by wet method, not only the coal slime recovery system is complicated, the recovery rate is low, but also the investment is large, the production cost is high, and it also causes damage to the environment while wasting resources. .

For dry coal preparation, although certain results have been achieved, such as the application of air-heavy medium fluidized bed and FX and FGX dry separators, it is also in line with the coal washing environment in the western and northern regions with drought and less water, but the dry method The effective lower limit particle size of coal preparation and separation is 6mm, and the sieves used in actual production still often have the problem of sieve clogging in the sieving and grading of 6mm and below particle sizes, and the poor adaptability of coal types cannot guarantee the classification efficiency. The circulating fluidized bed boiler used in the pit mouth power plant requires the feed particle size to be less than 8mm, so how to achieve 6mm particle size screening to meet the classification and separation requirements of the full particle size dry method and ensure the coal used for power generation by the circulating fluidized bed furnace, It is a technical problem to be solved urgently.

Contents of the invention

The purpose of the present invention is to provide a spiral air screen dedusting machine for dry classification before fine-grained coal separation. This dedusting machine can realize the random regulation of the classification particle size from 0 to 13mm according to the demand, thus realizing the 6mm The size-level screening meets the classification and separation requirements of the full-size dry method and ensures the coal used for power generation by circulating fluidized bed furnaces, thereby greatly improving the efficiency of classification and drying.

In order to achieve the above object, the present invention adopts the following technical solutions: a spiral air screen dedusting machine for dry classification before fine-grained coal selection, which includes the following components:

The primary classification area, the primary classification area includes a cylindrical first classification bin, a central column is arranged in the first classification bin, and a dust removal port is provided on the upper side of the first classification bin; at least one spiral coil is wound around the central post. A sorting screen, the upper side of the spiral sorting screen is provided with a feed inlet, and the lower side of the spiral sorting screen is at least provided with a first coarse material discharge pipe and a first fine material discharge pipe, and the first coarse material discharge pipe A guide partition for separating materials is arranged between the upward coarse material discharge port with the opening of the pipe and the upward fine material discharge port of the first fine material discharge pipe; the first fine material discharge pipe and the first fine material discharge pipe The discharge ports of the coarse material discharge pipes all protrude from the outside of the first classification bin, and the discharge ports of the first fine material discharge pipes communicate with the feed ports of the secondary classification area;

The spiral sorting screen includes a feeding screen surface arranged on the upper side and a bottom plate arranged on the lower side, and ventilation holes are arranged on the feeding screen surface; the side of the feeding screen surface and the bottom plate far away from the central column is provided with an outer A baffle, the top of the outer baffle protrudes from the upper side of the feeding screen, and the lower end of the outer baffle is connected to the bottom plate; the side of the feeding screen and the bottom near the center column is provided with an inner baffle, or The outer wall of the center column is connected with the feeding screen surface and the bottom plate to form an inner baffle; between the feeding screen surface and the bottom plate, a number of partition plates are arranged from the side close to the center column to the side away from the center column. The upper end of the dividing plate is in contact with the feeding screen surface, the lower end of the dividing plate is connected with the bottom plate, and the bending directions of the outer baffle plate and the dividing plate coincide; the upper side of the inner baffle plate, the feeding screen surface and the The area surrounded by the outer baffle constitutes the material channel connected with the feed inlet on the upper side of the spiral sorting screen; Separated several airflow passages; the upper side of the spiral sorting screen is also provided with an air supply port for supplying air to the airflow passage of the spiral sorting screen, and the air supply port is provided with a separate corresponding airflow passage for each airflow passage. air supply pipe;

The secondary classification area is equipped with a wind-forced rotation-driven classification mechanism, the feed port of the wind-forced rotation-driven classification mechanism is connected with the discharge port of the first fine material discharge pipe, and the wind-forced rotation-driven classification mechanism’s lower The side is provided with a secondary fine particle material discharge area and a secondary coarse particle material discharge area.

Simultaneously, the present invention can also be further realized in the following ways:

Preferably, the feeding sieve surface is composed of a plurality of adjacent elongated sieve bars, air holes are formed between two adjacent sieve bars, the upper surface of the sieve bars is smooth arc-shaped, and The bending direction of the upper surface of the bar coincides with the extension direction of the bottom plate where the bar is located. The upper end faces of the partitions are fitted together.

Further, the spiral sorting screen is provided with a supplementary air device for blowing air into the air flow channel.

Preferably, the air replenishing device includes an air replenishing pipe connected with a blower, the air replenishing pipe is provided with a damper for adjusting the air volume, and the air supply port of the air replenishing pipe passes through the outer baffle plate of the spiral sorting screen and the The air flow passages are connected, and the partition plate in the spiral sorting screen is provided with a supplementary air gap for the wind in the supplementary air pipe to pass through.

As another preferred solution of the present invention, the air supply device includes a main air duct connected to the fan, and the air supply end of the main air duct is provided with several branch pipes connected in parallel to each other, and the airflow in the spiral sorting screen is connected to the branch pipes. The channels correspond to each other; the bottom plate corresponding to each air flow channel is provided with an air supply port, and the air supply end of the branch pipe is connected with the air supply port.

Further, the air supply port on the bottom plate is covered with an air guiding elbow for making the added air enter the airflow channel along the material conveying direction.

Preferably, the guiding direction of the guiding partition is adjustable.

Preferably, the wind-driven rotation-driven grading mechanism in the secondary grading area includes a closed material grading area and a blanking area; the material grading area includes a secondary high-pressure jet air pipe, an elbow buffer member and an air guide plate, The pipe body of the secondary high-pressure injection air pipe is provided with a feed inlet connected with the first fine material discharge pipe, and the secondary high-pressure injection air pipe is connected with the elbow buffer member, and the discharge port of the elbow buffer member Set towards one side of the wind deflector. The wind deflector is smooth and arc-shaped and there are multiple sets. The area surrounded by the multiple wind deflectors constitutes the discharge end of the material classification area, and the passage between adjacent wind deflectors is formed. The air guide channel to the discharge end of the material classification area, and air holes are arranged above the air intake end of the air guide channel; the discharge end of the material classification area is connected to the blanking area.

Further, the blanking area includes a second grading bin, and a blanking barrel is arranged in the second grading bin, and the upper part of the blanking barrel is open, and the upper opening of the blanking barrel is set in the material grading area for discharge. Just below the end, the small edge of the upper opening area of the falling barrel is located inside the opening edge of the discharge end of the material classification area; the inside of the falling barrel constitutes the secondary fine particle material falling In the material area, the outer wall of the blanking cylinder and the inner wall of the second grading bin form a secondary coarse particle material blanking area for the secondary coarse particle material to pass through; the discharge port of the blanking cylinder is provided with a The inside of the barrel is an exhaust fan in a negative pressure area.

Beneficial effects of the present invention:

1), the present invention adopts the spiral airflow conveying classification method in the primary classification area, and adopts the tangential airflow jet rotary classification method in the secondary classification area.

In the primary classification area, the material continues to fall steadily along the material channel in the spiral classifying screen. During the falling process, the material collides with the feeding screen surface and the baffle plate in the spiral classifying screen, and at the same time receives the airflow conveying force provided by the airflow channel, so that the material is effectively dispersed, and is separated according to the particle size under the action of the spiral centrifugal force. Classification realizes the effective separation of primary fine material and primary coarse material.

The first fine material discharge pipe on the lower side of the first classification chamber introduces the primary fine material into the secondary classification area, and the primary fine material is subjected to secondary classification and coarse discharge through tangential airflow jet rotation, and the secondary classification area introduces downward negative pressure, It ensures that the material can be smoothly discharged without leaving coarse when the classification size is required to be large.

The present invention not only improves the classification efficiency, but also changes the current situation that traditional thermal coal must be depowdered and classified by sieves, removes the grading sieve, fundamentally solves the problem of sieve hole blockage, and realizes the grading particle size from 0 to 13mm according to It requires arbitrary regulation and provides a new technology for thermal coal de-powdering and washing.

2), the spiral sorting screen in the present invention is arranged around the central column, the upper side of the spiral sorting screen is provided with a feeding screen surface, and the lower side is set as an air flow channel. This double-layer structure effectively expands the dispersion area of the material . At the same time, the present invention is also provided with an air replenishment pipeline for replenishing gas to the airflow channel, which ensures smooth material delivery. At the same time, the air flow size and air supply volume of the air replenishment are adjustable, avoiding the occurrence of dead zones in the process of air flow conveying materials, and ensuring In order to transport materials smoothly, it is beneficial to improve the classification efficiency.

3), the present invention increases the lower limit of 13mm sieving particle size, which is difficult for traditional screening machines to break through, to 6mm, which satisfies the optimal lower limit of 6mm sieving particle size for dry coal preparation equipment, and is of great significance for improving the separation efficiency of dry coal preparation , It is also in line with the strategic needs of shifting the focus of my country's thermal coal washing and processing to the western and northern arid and water-poor regions.

4), the present invention can increase the optimum washing lower limit of semi-washing wet coal preparation, increase the washing ratio, optimize the product structure, simplify the coal slime water treatment system, reduce the amount of coal slime, and realize the economic benefits of thermal coal preparation plants maximize.

5), the present invention will be able to realize the classification of 8mm particle size, can be directly used as circulating fluidized bed power generation, and promote the strategic transformation of changing coal transportation into power transmission.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic cross-sectional structure diagram of a spiral sorting screen.

Figure 3 is a schematic diagram of the structure of the feeding screen surface.

Fig. 4 is a schematic diagram of the connection structure of the supplementary air pipe and the spiral sorting screen.

Figure 5 is a schematic diagram of the connection structure of the main air duct, branch pipes and spiral sorting screen.

Fig. 6 is a structural schematic diagram of an air guide elbow.

Fig. 7 is a structural schematic diagram of a classification mechanism driven by wind rotation.

The meanings of the marked symbols in the figure are as follows:

10-Primary classification area 20-Secondary classification area 21-Secondary high-pressure jet duct

22-Elbow buffer member 23-Wind deflector 24-Air hole

25-Discharge end of material classification area 26-Blanking barrel

27-Secondary fine particle material discharge area 28-Secondary coarse particle material discharge area

29-Second grading warehouse 30-First grading warehouse 31-Central column

32-dust removal port 33-spiral sorting screen 331-feed port 332-air supply port

333-feeding screen surface 333a-material channel 334-bottom plate 334a-baffle plate

334b-partition plate 334c-air flow channel 335-air supply gap

336-Air outlet 337-Air guide elbow 338-Sieve bar 339-Venture hole

34-Air supply device 341-Air supply pipe 342-Air valve 343-Main air duct

344-branch pipe 35-first coarse material discharge pipe 351-coarse material discharge port

36-First fine material discharge pipe 361-Fine material discharge port 37-Guide partition

Detailed ways

As shown in Figures 1 and 2, a spiral air screen dedusting machine used for dry classification before fine-grained coal selection includes the following components:

The primary classification area 10, the primary classification area 10 includes a cylindrical first classification bin 30, the first classification bin 30 is provided with a central column 31, and the upper side of the first classification bin 30 is provided with a dust removal port 32; the central column 31 is at least provided with a spiral sorting screen 33, the upper side of the spiral sorting screen 33 is provided with a feed port 331, and the lower side of the spiral sorting screen 33 is at least provided with a first coarse material discharge pipe 35 and a second A fine material discharge pipe 36, between the upward coarse material discharge port 351 of the opening of the first coarse material discharge pipe 35 and the upward fine material discharge port 361 of the first fine material discharge pipe 36, there is a separation The guide partition 37 of material; the discharge ports of the first fine material discharge pipe 36 and the first coarse material discharge pipe 35 all stretch out from the outside of the first classification bin 30, and the first fine material discharge pipe The discharge port of 36 is connected with the feed port of secondary classification area 20;

The spiral sorting screen 33 includes a feeding screen surface 333 arranged on the upper side and a bottom plate 334 arranged on the lower side, and the feeding screen surface 333 is provided with ventilation holes; One side of 31 is provided with outer baffle 334a, and the top of described outer baffle 334a stretches out on the upper side of feeding screen surface 333, and the lower end of outer baffle 334a links to each other with bottom plate 334; Described feeding screen surface 333 and bottom plate 334 The side near the central column 31 is provided with an inner baffle, or the outer wall of the central column 31 is connected with the feeding screen surface 333 and the bottom plate 334 to form an inner baffle; between the feeding screen surface 333 and the bottom plate 334 From the side close to the central column 31 to the side away from the central column 31, several partition plates 334b are provided, the upper end of the partition plate 334b is in contact with the feeding screen surface 333, and the lower end of the partition plate 334b is connected to the bottom plate 334, and The bending direction of described outer baffle plate 334a and dividing plate 334b coincides; The area surrounded by described inner baffle plate, the upper side of feeding screen surface 333 and outer baffle plate 334a constitutes the inlet and outlet with spiral sorting screen 33 upper side. The material channel 333a that feed opening 331 is connected; The area surrounded by described inner side baffle plate, feeding screen surface 333, bottom plate 334 and outer side baffle plate 334a constitutes some air passages 334c separated by dividing plate 334b; The upper side of the spiral sorting screen 33 is also provided with an air supply port 332 for supplying air to the airflow channel of the spiral sorting screen 33, and the air supply port 332 is provided with a separate air supply pipe corresponding to each airflow channel 334c;

The secondary classification area 20, the secondary classification area 20 is provided with a wind power rotation driving classification mechanism, the feed port of the wind power rotation driving classification mechanism is connected with the discharge port of the first fine material discharge pipe 36, and the wind power rotation driving classification The lower side of the mechanism is provided with a secondary fine particle material discharge area 27 and a secondary coarse particle material discharge area 28 .

The spiral sorting screen 33 is arranged in a spiral shape around the central column 31, and the effective distribution, dispersion and classification area is large, so that the materials can be fully dispersed, which is beneficial to classification and zoning.

The air supply port 332 of the spiral sorting sieve 33 is set as a plurality of airflow passages to enter the air simultaneously, and the air intake air volume and wind speed of each airflow passage 334c can be regulated by the air supply pipe corresponding to the airflow passage 334c independently, that is, a plurality of The air supply conditions of the airflow channels 334c are different and can be adjusted individually.

The lower side of the feeding screen surface 333 is in contact with the upper surface of the partition plate 334b, so that the airflow in the airflow channel 334c does not overflow, ensuring the conveying effect of the airflow to the material.

The feeding screen surface 333 can be selected from wear-resistant rubber with air holes. Preferably, as shown in Figure 3, the feeding screen surface 333 is composed of several elongated screen bars 338 adjacent to each other. Ventilation holes 339 are formed between adjacent sieve bars 338, the upper surface of the sieve bar 338 is smooth arc-shaped, and the bending direction of the upper surface of the sieve bar 338 matches the extension direction of the bottom plate 334 where the sieve bar 338 is located , the two sides of the sieve bar 338 along its length direction are respectively connected to the inner baffle plate and the outer baffle plate 334a, and the lower side of the sieve bar 338 is attached to the upper end surface of the partition plate 334b.

Further, as shown in FIG. 1 , the spiral sorting screen 33 is provided with a supplementary air device 34 for supplying air to the airflow channel 334c.

There are multiple implementation schemes for the supplementary air device. Preferably, as shown in FIG. 4 , the supplementary air device 34 includes a supplementary air pipe 341 connected to a fan, and the supplementary air pipe 341 is provided with a damper 342 for adjusting the air volume. The air outlet of the supplementary air duct 341 passes through the outer baffle plate 334a of the spiral sorting screen 33 and communicates with the air flow channel 334c, and the partition plate 334b in the spiral sorting screen 33 is provided with a supply and supplementary air duct The supplementary air gap 335 through which the wind in 341 passes.

As another preferred solution of the present invention, as shown in FIG. 5 , the air supply device 34 includes a main air duct 343 connected to the fan, and the air supply end of the main air duct 343 is provided with several branch pipes 344 connected in parallel with each other, so The branch pipe 344 corresponds to the airflow channel 334c in the spiral sorting screen 33 one by one; the bottom plate 334 corresponding to each airflow passage 334c is provided with an air supply port 336, and the air supply end of the branch pipe 344 is connected to the air supply port. 336 connected.

Further, the air outlet 336 on the bottom plate 334 is covered with an air guiding elbow 337 for making the added air enter the material passage along the material conveying direction.

Preferably, the guiding direction of the guide partition 37 is adjustable, that is, the guide partition 37 is movable connected with the coarse material discharge port 351 and the fine material discharge port 361, which is beneficial to adjust according to actual needs. The size of the separated particle size of the material, that is, the opening size of the feed ports of the first fine material discharge pipe 36 and the first coarse material discharge pipe 35 can be adjusted according to the actual particle size requirements.

Preferably, as shown in Figures 1 and 7, the wind-driven rotation-driven classification mechanism in the secondary classification area 20 includes a closed material classification area and a blanking area; the material classification area includes a secondary high-pressure jet duct 21 , elbow buffer member 22 and wind deflector 23, the pipe body of described secondary high-pressure jet air duct 21 is provided with the feeding port that communicates with the first fine material discharge pipe 36, and secondary high-pressure jet duct 21 is connected with The elbow buffer members 22 are connected, and the outlet of the elbow buffer member 22 is set toward the wind deflector 23 side. The formed area constitutes the discharge end 25 of the material classification area, and the air guide passage leading to the discharge end 25 of the material classification area is formed between adjacent air deflectors, and an air hole 24 is arranged above the air inlet end of the air guide passage; The discharge end 25 of the material classification area communicates with the discharge area.

The air inlet of the second classification bin 29 is composed of two adjacent air deflectors 23 connected to the second classification bin 29, so as to ensure that the materials in the transition section can all enter the second classification bin 29 for secondary classification .

Further, as shown in Figures 1 and 7, the blanking area includes a second classification bin 29, and a blanking cylinder 26 is arranged inside the second classification bin 29, the upper part of the blanking cylinder 26 is open, and the blanking The upper opening of the cylinder 26 is arranged directly below the discharge end 25 of the material classification area, and the small edge of the upper opening area of the blanking cylinder 26 is located inside the opening edge of the discharge end 25 of the material classification area; The inside of the cylinder 26 forms a secondary fine particle material blanking area 27 for the secondary fine particle material to pass through, and a secondary secondary fine particle material for the secondary coarse particle material to pass is formed between the outer wall of the blanking cylinder 26 and the inner wall of the second classification bin 29. Coarse particle material blanking area 28; the discharge port of the blanking cylinder 26 is provided with an exhaust fan to make the inside of the blanking cylinder 26 a negative pressure area.

The setting of the exhaust fan ensures that the material can be discharged smoothly when the classification size is required to be large.

The working process of the present invention will be further described below in conjunction with FIGS. 1-7.

As shown in FIG. 1 , the primary classification area 10 is also the spiral airflow conveying classification area, which mainly consists of a first classification bin 30 , a central column 31 , a spiral sorting screen 33 and an air supply device 34 . Among them, the spiral sorting screen 33 adopts the structure of double helix arrangement center column, and has two feed ports 331, two air supply ports 332, coarse material discharge port 351, fine material discharge port 361 and two air discharge ports 32 . The spiral sorting screen 33 is in a spiral shape and consists of an upper and a lower layer structure, wherein the upper layer is the feeding screen surface 333, the lower layer is the bottom plate 334, and the outer edge of the spiral sorting screen 33 is an outer baffle plate higher than the feeding screen surface 333 334a, the inside edge of the spiral sorting screen 33 is the cylinder wall of the central column 31; the bottom plate 334 is divided into several air passages with the partition plate 334b on the bottom plate 334, and the upper edge of each partition plate 334b is connected with the feeding screen The lower end surfaces of the surfaces 333 are in contact.

The air supply device 34 is used to supply air to each airflow channel. As shown in FIG. 5 , the air supply branch pipe 344 is supplied with air by an air supply mechanism such as an air compressor. An angle-adjustable guide partition 37 is provided at the discharge port of the spiral sorting screen 33, and the grading particle size can be adjusted as required. The first classifying bin 30 is provided with an air-introduction dust removal port 32 connected with a dust remover.

After the air flows through each separate air supply pipe into the airflow channel 334c corresponding to the air supply pipe at the two air supply ports 332, the material is passed through the two feed ports 331 respectively along the inclination of the feeding screen surface 333 of the spiral sorting screen 33. The material is fed in the same direction, and the material is moved downwards along the feeding screen surface 333 by its own gravity and the airflow conveying force provided by the airflow channel 334c in the spiral sorting screen 33. At the same time, the large and small particles are classified under the action of centrifugal force to form different The granularity-level material belt is separated at the guide partition 37 to obtain a primary coarse material and a primary fine material. The obtained primary coarse material is discharged and collected through the first coarse material discharge pipe 35, and the primary fine material is discharged through the first fine material. The pipe 36 falls into the secondary high-pressure injection air pipe 21, thereby completing the primary classification.

The material entering the secondary high-pressure jet duct 21 enters the elbow buffer member 22 under the impingement of the secondary high-pressure air. The air guide channel formed by the plate 23 is classified under the action of centrifugal force to obtain the secondary coarse particle material and the secondary fine particle material, wherein the secondary fine particle material passes through the material classification area under the negative pressure in the blanking cylinder 26 The discharge end 25 enters the inner side of the blanking barrel 26 and is collected after being discharged; while the secondary coarse particle material falls into the coarse particle material blanking formed between the outer wall of the blanking barrel 26 and the inner wall of the second classification bin 29. Zone 28 is then discharged, thereby completing secondary classification.

Claims (9)

1. one kind is used for the spiral pneumatic jig powder remover that Bed for Fine Coal is selected front dry classification, it is characterized in that comprising following part:

Scalping district (10), scalping district (10) comprises the first classification storehouse (30) of tubular, be provided with newel (31) in the first classification storehouse (30), and the upside in the first classification storehouse (30) is provided with dedusting mouth (32); At least be arranged with a spiral separating sieve (33) on the described newel (31), the upside of described spiral separating sieve (33) is provided with charging aperture (331), the downside of spiral separating sieve (33) is provided with the first thick discharge of materials pipe (35) and the first thin discharge of materials pipe (36) at least, is provided with the guiding dividing plate (37) of being convenient to separate material between the thin material discharge gate (361) of the thick material discharge gate (351) of the opening upwards of the described first thick discharge of materials pipe (35) and the opening upwards of the first thin discharge of materials pipe (36); The discharge gate of the described first thin discharge of materials pipe (36) and the first thick discharge of materials pipe (35) all stretches out in the outside in the first classification storehouse (30), and the discharge gate of the described first thin discharge of materials pipe (36) is connected with the charging aperture of secondary grading district (20);

Described spiral separating sieve (33) comprises the feeding compass screen surface (333) that is arranged on upside and the base plate (334) that is arranged on downside, and described feeding compass screen surface (333) is provided with air-permeating hole; Side away from newel (31) of described feeding compass screen surface (333) and base plate (334) is provided with outer side shield (334a), the upside in feeding compass screen surface (333) is stretched out at the top of described outer side shield (334a), and the lower end of outer side shield (334a) links to each other with base plate (334); One side of the close newel (31) of described feeding compass screen surface (333) and base plate (334) is provided with interior side shield, and perhaps the outer wall of described newel (31) links to each other to consist of interior side shield with described feeding compass screen surface (333) with base plate (334); Extremely be provided with some demarcation strips (334b) away from newel (31) one sides from close newel (31) one sides between described feeding compass screen surface (333) and the base plate (334), the upper end of described demarcation strip (334b) contacts with feeding compass screen surface (333), the lower end of demarcation strip (334b) links to each other with base plate (334), and the bending direction of described outer side shield (334a) and demarcation strip (334b) matches; The zone that the upside of described interior side shield, feeding compass screen surface (333) and outer side shield (334a) surround consists of the material channel (333a) that is connected with the charging aperture (331) of spiral separating sieve (33) upside; The zone that described interior side shield, feeding compass screen surface (333), base plate (334) and outer side shield (334a) surround consists of some gas channels (334c) of being separated by demarcation strip (334b); The upside of described spiral separating sieve (33) also be provided with blow in the gas channel of spiral separating sieve (33) for air port (332), described air feed (332) is located to be provided with and the independent corresponding airduct that supplies of each gas channel (334c);

Secondary grading district (20), be provided with Wind-driven rotating in the secondary grading district (20) and drive classification mechanism, the charging aperture that Wind-driven rotating drives classification mechanism is connected with the discharge gate of the first thin discharge of materials pipe (36), and the downside that described Wind-driven rotating drives classification mechanism is provided with secondary fine granular materials feeding zone (27) and secondary coarse granule material feeding zone (28).

2. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 1, it is characterized in that: described feeding compass screen surface (333) is made of the grating (338) of several strips adjacent one another are, consist of air-permeating hole (339) between the two adjacent gratings (338), it is smooth circular-arc that the upper surface of described grating (338) is, and the bending direction of grating (338) the upper surface therewith bearing of trend of the base plate (334) at place, grating (338) place matches, the both sides along its length direction of described grating (338) link to each other with outer side shield (334a) with interior side shield respectively, and the upper surface of the downside of grating (338) and demarcation strip (334b) fits.

3. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 1 is characterized in that: be provided with to the air compensation device (34) of the middle air-supply of described gas channel (334c) on the described spiral separating sieve (33).

4. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 3, it is characterized in that: described air compensation device (34) comprises the secondary air channel (341) that links to each other with blower fan, be provided with the air-valve (342) for regulating air volume on the secondary air channel (341), the outer side shield (334a) that the air outlet of described secondary air channel (341) passes spiral separating sieve (33) is connected with described gas channel, is provided with the benefit wind space (335) of passing through for the wind in the secondary air channel (341) on the demarcation strip (334b) in the described spiral separating sieve (33).

5. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 3, it is characterized in that: described air compensation device (34) comprises the air main (343) that links to each other with blower fan, the air-supply end of air main (343) is provided with the some arms (344) that are connected in parallel to each other, and described arm (344) is corresponding one by one with the gas channel that spiral separating sieves in (33); Be provided with air outlet (336) on the described base plate corresponding with each gas channel (334), the air-supply end of described arm (344) links to each other with air-supply (336).

6. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 5, it is characterized in that: the air outlet (336) on the described base plate (334) locates to be covered with the wind-guiding elbow (337) that makes the wind that fills into enter gas channel along the mass transport direction.

7. each described spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 2～6, it is characterized in that: the guiding direction of described guiding dividing plate (37) is adjustable.

8. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 1, it is characterized in that: the Wind-driven rotating in the described secondary grading district (20) drives stock grading district and the feeding zone that classification mechanism comprises closed; Described stock grading district comprises that secondary high-pressure sprays airduct (21), bend pipe buffer component (22) and wind deflector (23), be provided with the charging aperture that is connected with the first thin discharge of materials pipe (36) on the pipe shaft of described secondary high-pressure injection airduct (21), and secondary high-pressure sprays airduct (21) and is connected with bend pipe buffer component (22), the discharging opening of bend pipe buffer component (22) is towards wind deflector (23) one side settings, described wind deflector (23) is smooth curved arc shape and arranges a plurality of, the zone that a plurality of wind deflectors (23) surround consists of material graded region discharge end (25), consist of the air-guiding aisle that leads to stock grading district discharge end (25) between the adjacent wind deflector, and the top of the air intake of described air-guiding aisle is provided with pore (24); Described stock grading district discharge end (25) is connected with feeding zone.

9. the spiral pneumatic jig powder remover for dry classification before the Bed for Fine Coal choosing according to claim 8, it is characterized in that: described feeding zone comprises the second classification storehouse (29), be provided with blanking barrel (26) in the second classification storehouse (29), the top of blanking barrel (26) is uncovered shape, and the open topped of blanking barrel (26) be arranged on stock grading district discharge end (25) under, the little edge of open topped area of described blanking barrel (26) is positioned at the inboard of the edge of opening of stock grading district discharge end (25); The inside of described blanking barrel (26) consists of the secondary fine granular materials feeding zone (27) that passes through for the secondary fine granular materials, consists of the secondary coarse granule material feeding zone (28) that passes through for secondary coarse granule material between the inwall in the outer wall of blanking barrel (26) and the second classification storehouse (29); The discharging opening place of described blanking barrel (26) is provided with and makes blanking barrel (26) inside be the air exhauster of negative pressure region.

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