Raw coal is fed through a central coal inlet at the top of the pulverizer
and falls by gravity to the rotating grinding table, mixing with classifier
rejects returned for re-grinding. Centrifugal action forces the coal outward
to the grinding ring where it is pulverized between the ring and three
grinding rollers.
Grinding load, transmitted from the tension rods through the loading frame
to the roller assemblies, holds the rollers in contact with the grinding
ring. The rollers adjust vertically as the depth of the coal load increases
or decreases.
A nozzle ring on the outside perimeter of the grinding ring feeds primary
air to the pulverizer. Pyrites and tramp metal fall through the nozzle ring
openings to be scraped into a rejects hopper.
A stream of low-velocity air carries the particles of pulverized coal
upward where they enter the classifier inlet vanes. Fine particles travel to
the burners in the primary air stream, but the larger, heavier particles are
returned to the grinding zone for further pulverization.
DESCRIPTION: 
BMW's nozzles pipe are sintered alumina tube with excellent
temperature stability. They are popularly used as furnace tubes and
protecting and insulating tubes for high temperature thermocouple
assemblies. Because of their high purity and fine grain structure, BMW 's
nozzle pipes possess high wear resistance high strength, high thermal
conductivity and insulating properties.
The Al2O3 content of BMW 's nozzle pipes is more that 99% making it
perfectly suitable for use in Platinum/Platinum-Rhodium thermocouple as any
presence of silicate would contaminate these thermocouples and reduce their
service life.
BMW's nozzle pipes tubes are available in a variety of sizes with one end
closed as protection tubes or both ends open with 2-hole or 4-holes as
insulating tubes.
PROPERTIES:
Temperature stability up to 1800°C BMW's nozzles pipe tube
exhibit stability at temperature as high as 1,800°C giving it advantage
over metal or glass material. Application temperature also is influenced by
the tube geometry, the diameter, the wall thickness and the method of
installation i.e., horizontal or vertical.
High chemical resistance BMW's nozzle pipes has excellent chemical
resistivity and are corrosion resistant against most acids and alkaline.
Also, the stability in neututral or reducing atmosphere is excellent.
High electrical insulation. Due to its very high electrical
insulation properties, BMW's nozzle pipes is ideal as thermocouple wire
insulating tubes and thermocouple protection tubes even in electrically
heated furnaces.
Mechanical wear resistance Due to high mechanical wear resistance
BMW's nozzle pipes tubes exhibits long term stability even when subjected to
abrasive environment.
Dimensional flexibility. Various standard sizes are available from
0.5 mm through 300 mm in diameter. Tubes with non-standard sizes can be
offered in accordance with customer’s specifications and dimensions
FEATURES:
- High dimensional tolerance
- Chemical corrosion resistance
- High heat resistance
- Very good thermal conductivity
- Very high wear resistance
- Very high mechanical & refractory strength, very hard
- High degree of reliability and economy in service
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