CN104803198A - Pneumatic conveying device - Google Patents

Abstract

The invention relates to a pneumatic conveying device, which comprises a base, a silo, a material inlet, a discharge pipe one, a fan No. 1, a feed pipe one, a collection pipe one, a collection device one, and a discharge pipe two , No. 2 fan, pipeline, feeding pipe 2, collecting pipe 2, collecting device 2, discharging pipe 3, fan No. 3, collecting pipe 3, collecting device 3, scraper system, filter screen, cutter wheel. The invention installs a powder concentration detection device on the pipeline, and controls the rotation speed of the main shaft motor through the detection signal to control the powder concentration, that is, the mesh number of the powder. By judging the powder concentration, different mesh powders can be distinguished. In this way, the number of collecting fans can be reduced, the work efficiency of the pneumatic conveying device can be improved, and the degree of automation of the machine can be enhanced.

Description

Pneumatic conveying device

technical field

The invention relates to the technical field of pneumatic conveying, and more specifically, the present invention relates to a device for pneumatically conveying materials.

Background technique

Pneumatic conveying device, also known as pneumatic lifting system, is a device that uses the energy of air to continuously convey and lift powdery bulk materials (cement, fly ash, slag powder, clinker, etc.). Traditional mechanical lifting equipment has the advantages of large lifting capacity, rich types of lifting, and high lifting height, and is widely used in various industries in today's society. However, it also has many disadvantages that cannot be underestimated. The price of the equipment is high, the one-time investment is large, the amount of maintenance is large, it is difficult to operate, the weight of the equipment is large, the investment in civil engineering is large, the area is large, and it is restricted by site conditions. From the perspective of industrial applications, the transportation of materials accounts for a large proportion in actual production, and most of the power is consumed in the transportation of raw materials or products. Selecting and designing reasonable transportation methods has become an important part of improving production efficiency and reducing costs. . As we all know, the circulation process of cement, fly ash, slag powder, clinker and other powder materials is bulk transportation and use, which has great social and economic benefits, especially for the production and consumption of cement and fly ash. However, for countries whose cement bulk ratio is still very low, the development of bulk transportation appears to have more potential and significance. The pneumatic lifting system can realize the delivery of powder materials to bulk-carrying tools (such as vehicles, ships, headers, container bags, etc.), supply materials to the mixing building of the concrete mixing station, and supply materials to the bulk warehouse and the grinding mill in the mill. Head warehouse supply, etc.

The method of using gas as a carrier to transport powder materials is also widely used in industrial fields such as laser cladding, spray welding, spray coating, metallurgy, and rapid prototyping. In each of the above application fields, improving the uniformity and accuracy of powder delivery during processing is a common problem faced by powder delivery in many application fields. The accuracy and stability of powder delivery affects the thickness of the coating during processing. , coating temperature and coating quality.

In the field of traditional pneumatic conveying technology, the commonly used powder feeding device is mainly used to adjust the powder delivery volume by adjusting the metering volume (groove volume, thread groove volume, etc.) and motor speed. The problem of powder output accuracy is only It involves the category of powder output from the powder feeder. In the powder conveying process, even if the powder output at the output port of the powder feeder is stable, the conveying quantity of the powder to the outlet of the conveying pipeline may not be accurate and stable after conveying in the pipeline. This is because the flow state of the powder in the pipeline is actually very complicated, which is related to the airflow velocity, the amount of powder contained in the airflow, and the material properties of the powder itself. The conveying state of the powder in the pipeline may be a suspension flow that is conveyed by the air flow pressure of the high-speed flow, or a plug flow that is pushed by the static pressure of the air flow, or a conveying method between the two air flow states. The transmission of powder in the pipeline may be stagnant and blown away alternately. Therefore, the accuracy of the powder output by the powder feeder cannot guarantee the stability of the powder output at the outlet of the pipeline after being transported through the pipeline. For stable transmission, it is necessary to detect the state of powder transmission in key parts of the pipeline.

Studies have shown that in the field of pneumatic conveying technology, powder concentration has a very important influence on the formed gas phase. At present, pneumatic conveying devices mainly focus on how to solve the technical problems mentioned above, but for the conveying object, that is, powdery materials or powder Concentration detection also failed to attract enough attention.

The present invention aims to provide a pneumatic conveying device for detecting/monitoring the concentration of powder materials.

Contents of the invention

For the problems existing in the prior art, the general purpose of the present invention is to provide a pneumatic conveying device.

In order to achieve the above object, the technical solution adopted by the present invention is: a pneumatic conveying device, comprising a base 1, a silo 2, a feed inlet 3, a discharge pipe 4, a No. 1 fan 5, a feed pipe 6, a collecting Material pipe one 7, material collector one 8, discharge pipe two 9, fan No. 10, pipeline 11, feed pipe 12, material collection pipe two 13, material collector two 14, discharge pipe three 15, No. fan 16, material collecting pipe 3 17, material collecting device 3 18, scraper system 19, filter screen 20, cutter wheel 21, wherein the material bin 2 is installed on the base 1, and the upper part of the material bin 2 is provided with a material inlet 3 , the inside of the feed bin 2 is provided with a filter screen 20, the bottom of the feed bin 2 is equipped with a cutter wheel 21, the cutter wheel 21 further crushes the unbroken block materials, the filter screen 20 is made into a shell form, and the filter screen 20 is set Inside the silo 2 and above the cutter wheel 20, the scraper system 19 is arranged outside the silo 2, the shape of the scraper of the scraper system 19 matches the internal shape of the silo 2, and the discharge pipe 4 is installed At the bottom of the cutter wheel 21, in order to collect the material leaked from the top of the cutter wheel, and transport it to the collector one 8 through the No. 1 fan 5, the side of the bin 2 is provided with a discharge pipe two 9 at the lower position , the material in the silo is further collected, and returned to the feed port 3 through the No. 2 fan 10, the pipeline 11 feed pipe 12, so that the material can form a cycle, and further crushed by the cutter wheel 21, thereby obtaining a finer grain The feed pipe 12 is also connected to a tee, through which the tee is connected to the collection pipe two 13 and the collector two 14 in turn, so as to collect some materials; the side of the feed port 3 is connected to the feed pipe one 6. Feed pipe one 6 conveys part of the materials to the collector one 8 through the No. 1 fan 5; the top of the silo 2 is provided with a discharge pipe 3, and the rest of the materials are conveyed through the No. 3 fan 16 and the collection pipe 3 17 To the collector 18; a concentration detection device is installed on the pipeline 11.

Further, the material is cement, fly ash or metal powder; further, the concentration detection device adopts an optical fiber detection probe.

The beneficial effects of the present invention are:

By adopting the pneumatic conveying device of the present invention, it is possible to realize cyclic crushing of materials, obtain materials with finer meshes, and monitor the gas phase state of materials at the same time, so as to achieve a better conveying effect.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the pneumatic conveying device of the present invention.

In the figure, 1. Base 2. Stock bin 3. Feed inlet 4. Discharge pipe 1 5. No. 1 fan 6. Feed pipe 1 7. Collecting pipe 1 8. Collector 1 9. Discharge pipe 2 10. Fan No. 2 11. Pipeline 12. Feed pipe 2 13. Collecting pipe 2 14. Collector 2 15. Discharge pipe 3 16. Fan No. 3 17. Collecting pipe 3 18. Collector 3 19. Scraper system 20. Filter screen 21. Cutter wheel

Detailed ways

The specific implementation manners of the present invention will be briefly described below in conjunction with the accompanying drawings.

A pneumatic conveying device, comprising a base 1, a silo 2, a material inlet 3, a discharge pipe 4, a No. 1 fan 5, a feed pipe 6, a collection pipe 7, a collection device 8, a discharge Pipe two 9, No. two fan 10, pipeline 11, feed pipe two 12, collection pipe two 13, material collector two 14, discharge pipe three 15, No. three fan 16, collection pipe three 17, aggregate Device three 18, scraper system 19, filter screen 20, cutter wheel 21, wherein the feed bin 2 is installed on the base 1, the upper part of the feed bin 2 is provided with a feed port 3, and the inside of the feed bin 2 is provided with a filter screen 20, A cutter wheel 21 is installed at the bottom of the silo 2, and the cutter wheel 21 further crushes the unbroken bulk material. Above, the scraper system 19 is arranged on the outside of the silo 2, and the shape of the scraper of the scraper system 19 matches the internal shape of the silo 2, and the discharge pipe 14 is installed at the bottom of the cutter wheel 21, so that it can be seen from above the cutter wheel. The leaked material is collected, and transported to the collector one 8 through the No. 1 fan 5, and the side part of the silo 2 is provided with a discharge pipe 2 9 at a lower position to further collect the materials in the silo, and pass through No. 2 blower 10, pipeline 11 feed pipe 12 returns to the feed port 3, so that the material can form a circulation, and further crushed by the cutter wheel 21, thereby obtaining a finer material, the feed pipe 12 is also connected to one three Through the tee, connect the collection pipe 2 13 and the collection container 14 in turn, so as to collect some materials; the side of the feed port 3 is connected to the feed pipe 1 6, and the feed pipe 1 6 passes through the No. 1 fan 5 Convey part of the materials to the first collector 8; set the discharge pipe 3 on the top of the silo 2, and transfer the remaining materials to the collector 18 through the No. 3 fan 16 and the third collector pipe 17; install on the pipeline 11 Concentration detection device.

The main working principle of the present invention is that the raw material enters the silo 2 from the feed port 3, the spindle motor drives the cutter wheel 21 to rotate and cut at high speed, further crushes and refines the material, and uses the No. 2 fan 10 to form a circulating air flow, so that the powder can Circular cutting and collision can make the material crushed more fully. When the material is processed to a certain size, the powder will pass through the filter screen 20, and under the action of the scraper, it will enter the collection pipe, and the powder will be collected by the collection fans 5 and 16, and stored in the collector.

For the concentration detection device in the present invention, various detection devices in the prior art can be used. The following briefly introduces several commonly used concentration detection devices.

1. Measuring powder concentration by heat balance method. The principle of this method is that if the heat dissipation during the powder passing through the pipeline can be ignored, it can be assumed that the total heat of the powder blown into the pipeline by the wind remains stable, and the corresponding calculation formula can be obtained to determine the powder’s heat dissipation. concentration. This method is widely used in the detection of pulverized coal concentration, and is widely used in coal power plants at home and abroad.

2. The photoelectric detection sensor measures the powder concentration. It uses the principle of gas-solid two-phase flow, uses optical fiber as the detection element for the concentration and velocity of solid particles, injects the light beam into the detection range, and measures the induction signal of the light in the movement of the particles, and then the signal passes through the light. After electrical conversion and analog-to-digital conversion, analysis and calculation are carried out to obtain the measured particle concentration and velocity values. At present, the research on the photoelectric detection element shows that its main composition structure has the following forms: (1) optical fiber separation type, (2) parallel combination type, (3) mixed distribution type, (4) side-by-side dislocation combination type. When using the photoelectric detection measurement method, the measurement result is greatly affected by the structure of the optical fiber detection element and the diameter of the measured particle. In the concentration detection, the detection process is carried out locally, and the measured signal is the reflection state of the particles in this part. Generally, the form of increasing the illumination surface is used to obtain a good signal. Therefore, when using an optical fiber detection element, it is usually The diameter is much larger than that of the speed measuring fiber. There are reflection type and projection type in the form of photoelectric detection. For reflective applications, since the particle concentration of gas-solid two-phase fluid is defined as the proportion of particles in a unit volume, the optical fiber used for powder concentration measurement adopts multi-strand mixed distribution, and the most effective measurement area of the optical fiber detection element is The front end of the component is between 0.2-2.5mm, so the closer the measured object is to the end face of the fiber optic probe, the more conducive to the measurement of high-concentration airflow. This measurement method has a large gap in the measurement. During the measurement, the light can irradiate the front and rear sides of the particle and ensure that it is within the effective range. The reflected signal of the light can be well received by the receiving optical fiber. The particle concentration can then be accurately reflected by the measurement signal.

3. Microwave method. The current powder concentration measurement technology using microwave method includes: (1) using microwave phase shift and attenuation to measure powder concentration; (2) using microwave Doppler shift to measure flow velocity.

4. Electrothermal method. This method uses the working principle of the hot air anemometer to place an electrically heated sensing probe in the measured gas-solid two-phase flow. Media with different particle diameters, concentrations and flow velocities will have different heat transfer effects with the sensing probe. Under the condition of determining the delivery air volume, the flow rate of solid phase particles in the gas-solid two-phase fluid can be calculated according to the temperature of the measuring sensor probe and the electric heating power.

In a word, those skilled in the art can use the powder detection device in the prior art to realize the powder concentration detection of the present invention.

The invention installs a powder concentration detection device on the pipeline, and controls the rotation speed of the main shaft motor through the detection signal to control the powder concentration, that is, the mesh number of the powder. By judging the powder concentration, different mesh powders can be distinguished. In this way, the number of collecting fans can be reduced, the working efficiency of the pneumatic conveying device can be improved, and the degree of automation of the machine can be enhanced.

An embodiment of the present invention has been described in detail above, but the content described is only a preferred embodiment of the present invention, and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the application scope of the present invention shall still belong to the scope covered by the patent of the present invention.

Claims (3)

1. A pneumatic conveying device, characterized in that the device comprises a base, a feed bin, a feed inlet, a discharge pipe one, a No. 1 blower fan, a feed pipe one, a collection pipe one, a collector one, a discharge pipe Feed pipe 2, No. 2 fan, pipeline, feed pipe 2, material collecting pipe 2, material collector 2, discharge pipe 3, fan No. 3, material collecting pipe 3, material collector 3, scraper system, filter Net and cutter wheel, wherein the hopper is installed on the base, the upper part of the hopper is provided with a feed port, the inside of the silo is provided with a filter screen, and the bottom of the silo is installed with a cutter wheel. After further crushing, the filter screen is made into a shell form. The filter screen is set inside the silo and above the cutter wheel. The scraper system is set outside the silo. The scraper shape of the scraper system is consistent with the internal shape of the silo. Matching, the discharge pipe 1 is installed at the bottom of the cutter wheel, so as to collect the material leaked from above the cutter wheel, and transport it to the collector 1 through the No. 1 fan. The second material pipe is to further collect the material in the silo, and return it to the feeding port through the No. 2 fan and the pipeline feeding pipe, so that the material can form a cycle, and then be crushed by the cutter wheel, so as to obtain a finer material , the feeding pipe is also connected with a three-way, through which the three-way is connected to the second collection pipe and the second collection device in turn, so as to collect some materials; the side of the feed port is connected to the first feeding pipe, and the first feeding pipe passes through The No. 1 fan sends part of the materials to the first collector; the top of the silo is equipped with a discharge pipe, and the rest of the materials are sent to the collector through the No. 3 fan and the third collector; a concentration detection device is installed on the pipe. 2. The pneumatic conveying device according to claim 1, wherein the material is cement, fly ash or metal powder. 3. The pneumatic conveying device according to claim 1, characterized in that said concentration detection device adopts an optical fiber detection probe.