Selection of control channels for jigs
Coals are only separated effectively into density fractions when the jig bed is periodically loosened over its entire thickness up to the uppermost layers. The extent to which the jig bed is loosened can be evaluated by means of the relative loosening coefficient. The exent of loosening is influenced by the bed depth and the pulsation amplitude. If the depth of the compacted bed is stabilized at a specified level, the extent of loosening is uniquely determined by the amplitude. A constant extent of bed loosening can be maintained by controlling the amplitude by means of an automatic control system which regulates the air pressure in the air compartment of the jig. The bed depth and pulsation amplitude are themselves influenced by variables, including the coal input rate, the size- and density-fraction analysis, the discharge rate, the amplitude and frequency of the air pulsations, etc. In order to decide which control channels should be selected, trials were carried out on a type OM-18 jig in commercial use. 1. A mathematical model has been set up for the jigging process. From data on the possible control actions and the resulting ashes of the products, the selected control channels are: the discharge rotor speeds, the bed depths in each chamber, the angular setting of the air baffle (air-line damper), and the bed pulsation amplitudes in each chamber. 2. The most important factor is the outlet rotor speed in chamber II. 3. Controlling the depth and pulsation amplitudes of the beds in each chamber does not adequately stabilize the ashes of the products; their variances are only reduced by 40 to 50%. 4. Washeries which receive coals from a variety of sources must constantly correct the jigging conditions in the light of data on ashes.
- OSTI ID:
- 6690634
- Journal Information:
- Coke Chem. USSR (Engl. Transl.); (United States), Journal Name: Coke Chem. USSR (Engl. Transl.); (United States) Vol. 8; ISSN COKCA
- Country of Publication:
- United States
- Language:
- English
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ASIA
COAL PREPARATION
COMMINUTION
CONCENTRATORS
CONTROL SYSTEMS
DATA
EASTERN EUROPE
EUROPE
EXPERIMENT PLANNING
EXPERIMENTAL DATA
FEEDBACK
INFORMATION
JIGS
MATHEMATICAL MODELS
MATHEMATICS
NUMERICAL DATA
OPTIMIZATION
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PULSE TECHNIQUES
REGRESSION ANALYSIS
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USSR