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Wastewater grinder |
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Solid waste recycling system |
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Huanchuang (Xiamen) Technology Co.,Ltd
Phone: ：+86 592 5029670
Fax: +86 592 5029673
Email:info@hcwater.com
Add; 22 Guanri Road, Software Park 2, Xiamen, China
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| On the garbage crusher crushing work introduction |
| Edited：HuanChuang technology Date：2012-11-9 16:59:54 |
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The high pressure grinding rolls, often referred to as HPGRs or roller press, consists out of two rollers with the same dimensions, which are rotating against each other with the same circumferential speed. The special feeding of bulk material through a hopper leads to a material bed between the two rollers. The bearing units of one roller can move linearly and are pressed against the material bed by springs or hydraulic cylinders. The pressures in the material bed are greater than 50 MPa. In general they achieve 100 to 300 MPa. By this the material bed is compacted to a solid volume portion of more than 80%.
The roller press has a certain similarity to roller crushers and roller presses for the compacting of powders, but purpose, construction and operation mode are different.
Extreme pressure causes the particles inside of the compacted material bed to fracture into finer particles and also causes microfracturing at the grain size level. Compared to ball mills HPGRs are achieving a 30 to 50% lower specific energy consumption, although they are not as common as ball mills since they are a newer technology.
A similar type of intermediate crusher is the edge runner, which consists of a circular pan with two or more heavy wheels known as mullers rotating within it; material to be crushed is shoved underneath the wheels using attached plow blades.
Primary air in the case of Tube Mill have dual function to perform. It is used as drying as well as transporting media and by regulating the same the Mill output is regulated. Governed by the pulverize fuel outlet temperature requirement the combination of cold air and hot air dampers are regulated to have proper primary air temperature. In addition to raising the coal temperature Inside the Mill for drying and better grinding the same air works carrying media for pulverized coal through annular space between fixed trunnion tube and rotating hot air tube on way to classifier. Coal-laden air passing through Double cone static classifiers with adjustable classifier vanes for segregation Into pulverized fuel of desired fineness and coarse particles continues its journey towards coal burners for combustion. Coarse particles rejected in classifier find their way back to mill for another cycle of grinding. In order to avoid excess sweeping of coal from Mill Only Part Of the primary air, directly proportional to the boiler load demand is passed through Mill. Further to ensure and maintain sufficient velocity of pulverized fuel and to avoid settling in P.F. pipes an additional quantity of primary air is fed in to mixing box on raw coat circuit. This by-pass air tapped from the primary air duct going in Mill makes appreciable contribution for drying of raw coal by flash drying effect in addition to picking pp the pulverized fuel from Mill outlet for its transportation towards classifiers. Tube mill output while responding to boiler load demand is controlled by regulating primary air-flow. Such regulation by sweeping away of pulverized fuel from Mill being very fast rather well comparable with oil firing response, needs coal level to be maintained in the Mill. Mill level control circuit sensing the decreased coat level in Mill increases the speed of raw coal feeder and vice avers. Maintaining the coal level in Mill offers built-in-capacity cushion of pulverized fuel to take care of short interruption in raw coal circuit. The mill is pressurized and the tightness is ensured by plenum chambers around the rotating trunnion filled with pressurized seal air. Bleeding seal air from plenum chamber to Mill provides air cushion between pulverized fuel in the Mill and the outside atmosphere. Inadequacy or absence of seal air will allow escape of pulverized fuel into atmosphere. On the other hand excess of seal air leaking into Mill will affect the Mill outlet temperature. As such the seal air is controlled by a local control damper by maintaining just sufficient differential pressure for sealing. |
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