Questionnaire For Vibrating Screen
SCREENING DUTIES
Where bulk materials are divided into coarse granulation ranges and where in
some cases extreme sizing accuracy is not required, for example limestone and
granite for roadmaking, gravel for the concrete and building industry and coal
for the domestic, industrial and national power undertakings.
The cleaning up of built materials to remove those particles less than the
granulation range which in the main have been caused by degradation.Protective
screening and the extraction of oversize particles The removal of impurities, foreign bodies and lumps which greatly exceed
the required granulation range.
In the conditioning and processing of bulk materials the action of screening,
extraction and separating are among some of the most important functions of
process technology. We define and subdivide these as follows:
FINE GRADING
is normally associated with the particle sizes less than 3mm down to 53mm. A
typical example is carborumdum for the abrasives industry where a high degree
of separating accuracy is required. Generally speaking, the finer the
granulation the greater the screening effort that is required and where the
borderline to other screening definitions such as sifting and filtering is not
clearly defined.
DEDUSTING AND THE EXTRACTION OF UNDERSIZE PARTICLES
SEPARATION
of coarse material from fines. Primary crushes should not normally be burdened
with high percentages of the material. In this case a scalping separation of
the fine material can be achieved with a bar or grizzly screen. This type of
screen has the added advantage of permitting the fines to be fed direct to the
takeaway conveyor in advance of the material being crushed and which provides
a cushion to protect the conveyor belt. This type of separation is also used
in foundries to separate castings from moulding sand.