The feed screw feeder seal device

Biomass is the most widely used on Earth material, biomass is an important area of ​​application of biomass gasification. Circulating fluidized bed gasification is a major biomass

gasification technology, which is the basic principle feedstock gasification in a fluidized state. Biomass burning in the lower part of the bed,

The upper part of the bed gasification, carbon particles blown collected by various separation down, back to the bed gasification cycle. The technology for fuel adaptability,

gasification temperature is lower, and the large-scale continuous production. Circulating fluidized bed gasification technology in recent years has been the rapid development

and application.
Looking abroad circulating fluidized bed gasification plant, the raw material feeding device is always flawed, the most important is the feeder sealing problems. Positive

pressure circulating fluidized bed system, in order to prevent leakage of air flow inside the furnace, you must cut off the feeder connected with the outside world. Usually do

Method is to use the feed to seal off the wind, but the effect is poor. Here straw as raw material, the application of material sealed screw feeder device solved the problem of

feeding seals.  food conveyor
First, the screw feeder material sealed principle
Screw feeder is installed in the center axis of the helical segments, the shaft and the helical segments in a fixed rotation within the housing, with the function of a

mechanical device to transport raw materials. When changing the pitch of the helix or spiral path, the transmission capacity of the feeder will change, through the transmission

capacity feeder

Changes in the raw material accumulation within the feeder, which play a role in sealing material, which is material sealed.
Spiral material sealed feeder (also known as material sealed auger) has the following features.
1 screw feeder transport distance is short, usually no more than 3m;
2 screw feeder for mobility, non-tacky or sticky little or no pondering pondering the nature of small powder granular materials, raw material particle size generally less than

50mm, the moisture content does not apply to large, hard, pondering of the great and highly viscous materials;
3 screw feeder is a relatively closed system, transmission capacity is relatively small, the power consumption is relatively large.
Second, the screw feeder basic form of seal material
1 tapered spiral feeder
Tapered spiral feeder is in a certain period in the shaft diameter or pitch screw feeder diminishing. When taking a certain value, these two forms of transmission capacity

feeder is reduced, but the raw material into the feeder throughput is certain. When the material is to a certain extent the backlog,  mine conveyors

Voids between the particles of raw materials will be gradually reduced to a certain extent when the gap is narrow, it will cut off the outside of the feeder and ventilation, so

that to achieve the purpose of sealing.
2 Disconnect the spiral feeder
Disconnect the spiral feeder is removed in a certain period in the axis of the spiral chip conveyor while it declined sharply in the feeder, the feeder this form and tapered

sealing principle type feeder, like, the difference the material handling capability.
Third, the analysis and discussion
Take 3 different granularity, hardness and elasticity of materials, such as corn stalks (20-40mm), peanut shells, rice husk powder (0.1-1mm), to prepare a current tester,

blowers, and grouping experiments, corresponding current, length, and the sealing performance (room temperature only

Sealing performance).
Sealing screw feeder structures, there are many, the principle is basically the same, are transported by reducing the amount of raw materials played a role in the backlog, so as

to achieve the purpose of sealing. But their structure is relatively complex, processing difficulties, maintenance inconvenience.
CONCLUSIONS
1 Seal screw feeder design difficulty is necessary to ensure sealing, but also to ensure smooth transportation of raw materials, which are mutually contradictory problems.

Meanwhile, the different materials required for sealing the length of the seal segments may also vary widely, but also because even if the same particle size as a raw material,

changes in humidity and other factors,

The sake of change. To design a rational sealing screw feeder should be based on the theoretical analysis, combined with a large number of experiments to determine a reasonable

design.
(2) For the circulating fluidized bed is recommended to choose the middle disconnect type screw feeder, first, because of its good sealing effect, the fluidized bed of the

powder material is particularly suitable: two because the feeder middle seal segments in the pipeline , thus reducing the material temperature of the internal temperature of the

bed.