CN103359462B - A kind of screw feeder for coal-burned industrial boiler - Google Patents

Abstract

The invention discloses a screw feeder for coal-fired industrial boilers, which comprises a motor, a feeding bin and a feeder barrel, a horizontal screw shaft is built in the feeder barrel, and the output shaft of the motor is connected to the horizontal screw One end of the shaft is fixedly connected, and the feed bin communicates with the feeder barrel. In addition, it also includes a downwardly inclined buffer bin, overflow bin and discharge bin. The discharge end of the feeder barrel is connected to the overflow through the buffer bin. The barrel is connected; the overflow barrel is built in the discharge bin and the overflow barrel is sealed and connected with the discharge bin. The upper part of the overflow barrel is provided with an upper overflow port, and the coal powder in the overflow barrel goes upward through the upper overflow port. Diffusion into the discharge bin; the lower part of the discharge bin is provided with a discharge port. The invention can be widely used in various pulverized coal boilers. The invention can prevent the influence of the pressure fluctuation in the boiler on the coal feed, ensure that the pulverized coal will not flow back into the barrel of the feeder, and ensure the accuracy of the coal feed and the stable operation of the boiler.

Description

A screw feeder for coal-fired industrial boilers

technical field

The invention relates to a feeder for coal-fired industrial boilers, in particular to a screw feeder.

Background technique

Industrial boilers using clean pulverized coal are a new type of pulverized coal combustion technology, which has the characteristics of high efficiency (up to 88%) and low pollutant emissions, and is a promising technology. Due to the nature of combustion, the pulsation of the flame creates pressure fluctuations during the combustion process. Large boilers are generally equipped with multiple burners symmetrically distributed, and the fluctuations caused by combustion will roughly cancel out in the furnace. Small pulverized coal-fired industrial boilers generally use only one pulverized coal burner, and the furnace is small. This kind of fluctuation due to combustion cannot be offset in time, and the furnace pressure wave will be quickly transmitted to the pulverized coal feed along the powder delivery pipeline. machine office. For the existing conventional screw feeder, as shown in Figure 1, the motor 1' drives the horizontal screw shaft 3' inside the feeder barrel 5' to rotate through the coupling 2', and the feed bin 4' is added The material is transported to the outlet 6' at the lower end of the feeder barrel 5'. In the existing screw feeder, the pressure fluctuation in the boiler will be transmitted to the cylinder 5' through the discharge port 6', causing fluctuations in the powder feeding amount. The fluctuation of the amount of pulverized powder will affect the amount of coal fed, which will further affect the combustion, thus forming a positive feedback that affects the stable operation of the boiler. The fluctuation of the pressure in the furnace may also cause the pulverized coal to flow back from the outlet to the screw feeder, resulting in an error in the amount of coal fed, which is also one of the reasons why the amount of coal fed to the boiler cannot be automatically adjusted. Moreover, when the return flow of pulverized coal is large, it is easy to cause blockage of coal feeding, resulting in accidents of coal breaking in the boiler, and the long spiral is also prone to jamming or twisting.

Contents of the invention

In view of the above problems, the object of the present invention is to provide an overflow screw feeder suitable for pulverized coal boilers, and the device is also suitable for conveying powdery materials in other fields.

In order to achieve the above object, the technical solution adopted by the present invention is: the screw feeder used for powdery materials in the present invention includes a motor, a feeding bin and a feeder barrel, a horizontal screw shaft is built in the feeder barrel, and the motor The output shaft of the output shaft is fixedly connected with one end of the horizontal screw shaft, and the feed bin communicates with the feeder cylinder. In addition, the present invention also includes a downwardly inclined buffer bin, an overflow bin and a discharge bin. The discharge end is communicated with the overflow barrel through the buffer bin; the overflow barrel is built in the discharge bin and is sealed and connected with the discharge bin, the upper part of the overflow barrel is provided with an upper overflow port, and the The pulverized coal diffuses upwards into the discharge bin through the upper overflow port; the lower part of the discharge bin is provided with a discharge port.

Further, the overflow barrel of the present invention has a built-in vertical screw shaft.

Further, the included angle between the buffer bin and the horizontal plane in the present invention is 30-60°.

Further, the discharge port of the discharge bin of the present invention is funnel-shaped.

Further, the top surface of the discharge silo in the present invention is circular arched.

Compared with the prior art, the present invention has the beneficial effects that: in the prior art, the pressure wave will be quickly transmitted to the feeder through the discharge port, causing fluctuations in the amount of coal discharged, and the returned pulverized coal is easy to flow out of the feeder. Accumulation on both sides of the feed port causes the screw shaft to be stuck or twisted. After adopting the structure of the present invention, the powder diffuses upwards from the upper overflow port of the overflow barrel into the discharge bin, and then is discharged from the discharge port at the lower part of the discharge bin, thereby damping the pressure wave and avoiding The influence of the pressure wave on the powder prevents the pulverized coal from flowing back into the barrel of the feeder, but gathers and falls in the discharge bin and re-enters the furnace. In addition, the vertical screw shaft in the overflow barrel further damps the transmitted pressure wave, prevents the pressure wave from affecting the coal feeding amount, and ensures that the coal powder will not flow back into the feeder barrel, ensuring the coal feeding amount accurate. After adopting the structure of the present invention, the problems of fluctuating amount of pulverized coal feeding and unsmooth feeding of pulverized coal caused by fluctuations in pipeline pressure are solved, effectively avoiding the phenomenon of coal feeding blockage, and avoiding the jamming or twisting of the screw shaft.

Description of drawings

Fig. 1 is the structural representation of pulverized coal feeder in the prior art;

Fig. 2 is a schematic diagram of the structure principle of the present invention;

Fig. 3 is the sectional view of the A-A section of Fig. 2;

Fig. 4 is a schematic diagram of the distribution of materials in the discharge bin;

Fig. 5 is the B-B sectional schematic diagram of Fig. 2;

In the figure: 1. Motor, 2. Coupling, 3. Horizontal screw shaft, 4. Feeding bin, 5. Feeder cylinder, 6. Buffer bin, 7. Upper overflow port, 8. Outgoing bin , 9, discharge port, 10, vertical screw shaft, 11. overflow barrel.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figures 2 to 5, the present invention includes a motor 1, a feed bin 4 and a feeder barrel 5, the feeder barrel 5 has a built-in horizontal screw shaft 3, and the motor 1 is connected to the horizontal screw shaft through a coupling 2. One end of the shaft 3 is fixedly connected, the feed bin 4 communicates with the feeder barrel 5, the discharge end of the feeder barrel 5 communicates with the overflow barrel 11 through the buffer bin 6, and the overflow bin 8 is provided with The barrel 11 and the overflow barrel 11 are sealed and connected with the discharge bin 8. The upper part of the overflow barrel 11 is provided with an upper overflow opening 7, and the coal powder in the overflow barrel can diffuse upwards into the discharge 8 through the upper overflow opening. The bottom of the discharge bin 8 is provided with a discharge port 9 .

A vertical screw shaft 10 is arranged inside the overflow barrel 11 , and the vertical screw shaft 10 is used to assist the coal powder to diffuse from the upper overflow port 7 to the discharge bin 8 . The setting of the discharge bin 8 and the vertical screw shaft 10 has a damping effect on the pressure wave transmitted by the boiler, so that it cannot be transmitted back into the feeder cylinder 5, so as to ensure that the pulverized coal will not flow back into the feeder Inside the machine barrel 5. The buffer bin 6 is inclined downward relative to the feeder cylinder 5, and the angle between the buffer bin 6 and the horizontal plane is preferably 30-60 degrees. The setting of the buffer bin 6 prevents materials from accumulating at the end of the barrel 5 of the feeder (ie, the discharge end). The discharge bin 8 has airtightness, and the overflow barrel 11 is sealed and connected with the discharge bin 8 to ensure that the material transportation is carried out in a sealed state. The top surface of the discharge bin 8 is rounded, and the rounded top surface is beneficial for the particles to slide down from the top surface to the discharge port 9 of the discharge bin 8 when they collide with the top surface. The discharge port 9 preferably has a funnel shape with a downward slope, so as to facilitate discharging.

Working process of the present invention is as follows:

The motor 1 is started, and the horizontal screw shaft 3 is driven to rotate through the coupling 2. The coal powder enters the coal feeder cylinder 5 from the feed bin 4, and is transported forward with the rotation of the horizontal screw shaft 3, and slides in through the buffer bin 6. In the overflow barrel 11, the vertical screw shaft 10 in the overflow barrel 11 is driven to rotate by another motor (not shown in the figure), and the rotating spiral blade prevents coal powder from accumulating at the bottom of the barrel. The spiral blade of 10 is driven upwards, and the good fluidity of the powder makes it overflow from the upper overflow port 7 and enter the discharge bin 8. The overflowed material falls in the discharge bin 8 and is transported into the boiler through the discharge port 9.

When the pressure in the boiler fluctuates, the discharge bin 8 and the vertical screw shaft 10 will have a damping effect on the pressure wave transmitted from the furnace, so that it cannot be transmitted to the barrel 5 of the feeder, so as not to cause fluctuations in the amount of powder fed. The material returned by the discharge port 9 will diffuse and settle in the discharge bin 8, and return to the boiler through the discharge port 9 again, but cannot return to the feeder barrel of the screw feeder through the upper overflow port 7. within 5. The arched top surface of the discharge bin 8 makes it easier for the spilled material to fall to the discharge port 9 when it collides with it. In addition, the arrangement of the buffer bin 6 avoids the accumulation of materials at the end of the horizontal screw shaft 3 .

Claims (5)

1. A screw feeder for coal-fired industrial boilers, which includes a motor, a feed bin and a feeder barrel, the feeder barrel is built with a horizontal screw shaft, and the output shaft of the motor is connected to the horizontal screw shaft. One end is fixedly connected, and the feed bin communicates with the feeder barrel. It is characterized by: it also includes a downwardly inclined buffer bin, overflow bin and discharge bin. The discharge end of the feeder barrel passes through the buffer bin and the overflow The barrel is connected; the overflow barrel is built in the discharge bin and the overflow barrel is sealed and connected with the discharge bin. The overflow barrel is built with a vertical screw shaft, and the upper part of the overflow barrel is provided with an upper overflow port. The pulverized coal diffuses upwards into the discharge bin through the upper overflow port; the lower part of the discharge bin is provided with a discharge port. 2. The screw feeder for coal-fired industrial boilers according to claim 1, wherein the angle between the buffer bin and the horizontal plane is 30-60°. 3. The screw feeder for coal-fired industrial boilers according to claim 1 or 2, characterized in that: the discharge port of the discharge bin is funnel-shaped. 4. The screw feeder for coal-fired industrial boilers according to claim 1 or 2, characterized in that: the top surface of the discharge bin is circular arched. 5. The screw feeder for coal-fired industrial boilers according to claim 3, characterized in that: the top surface of the discharge bin is arched.