| Oleg Systems Co. make all types of industrial dust | | | | materials will vary with the material, plant process, |
| collection systems. Dust collecting equipment is | | | | quantity involved and the collector design. Dry |
| available in numerous designs utilizing a number of | | | | collectors can be unloaded continuously or in |
| principles and featuring wide variation in | | | | batches through dump gates, trickle valves and |
| effectiveness, initial cost, operating and | | | | rotary locks to conveyors or containers. Wet |
| maintenance expense, space, arrangements and | | | | collectors can be arranged for batch removal or |
| material of construction. | | | | continual ejection of dewatered material by flight |
| Factors influencing dust collection equipment | | | | conveyors or draining as a slurry. Material |
| selection include: | | | | characteristics can influence other problems, such |
| * Concentration and particle size of contaminant. | | | | as packing and bridging of dry materials in dust |
| In most dust conveying systems, usual dust | | | | hoppers, floating of slurry forming characteristics |
| range from 0.1 to 100 micron - a rather wide | | | | in wet collectors, etc. |
| range of particle sizes. | | | | One of the most efficient type of dust collectors |
| * Degree of collection required. | | | | is Electrostatic Precipitator. |
| Evaluation will consider the need for high | | | | The principle of dust collection relies on the ability |
| efficiency high cost equipment such as | | | | to impart a negative charge to particles in the gas |
| electrostatic precipirators; high efficiency | | | | stream causing them to move and adhere to the |
| moderate cost equipment such as fabric or wet | | | | grounded or positively charged collector plates. |
| collector units; and the lower cost primary units | | | | Most precipitators are made for horizontal air flow |
| such as the dry centrifugal group. Degree of dust | | | | with velocities 100 to 600 fpm. The collecting |
| collection required can depend on plant location; | | | | plates or electrodes are parallel elements, usually |
| compariosn of quantities of material released to | | | | on 9-inch centers, and constructed in various |
| atmoshere with different type of dust collectors; | | | | ways including corrugated or perforated plates for |
| nature of contaminant - its salvage value or its | | | | rod curtains. The electrode rods are centered |
| potential as a health hazard, public nuissance or | | | | between the collector plates. Volatge difference |
| ability to damage property - and the requirements | | | | between electrode and plate is 60,000 to 75,000 |
| of the local or state air pollution regulations. | | | | volts in most designs. Collector plates of cylindrical |
| * Characteristics of air or gas stream. | | | | shapes surrounding the electrode tod are provided |
| High temperature gas streams exceeding 180 F | | | | where water is used to wash off collected |
| will prevent the use of standard cotton media in | | | | material and where the gas stream is under high |
| fabric collectors; presence of steam or | | | | pressure or vacuum. |
| condensation of water vapor will cause packling | | | | Removal of the collected material is obtained by |
| and plugging of air or dust packages in fabric and | | | | rapping or vibrating the elements either |
| dry centrifugal collectors. Chemical composition | | | | continuously or at predetermined intervals. |
| can attack fabric or metal in dry collectors and | | | | Vibration or unloading usually takes place without |
| cause extremely corrosive conditions when mixed | | | | stopping air flow through the cleaning cycle. |
| with water in wet type collectors. | | | | Pressure drop is low. Collection efficiency is high |
| * Characteristics of contaminant. | | | | and nearly uniform regardless of particle size |
| Chemical composition can cause attack on dust | | | | including sub-micron particles. Space is relatively |
| collector elements or corrosion in wet type dust | | | | large and cost is high where small gas volumed |
| collectors. Sticky materials like metallic buffing dust | | | | (below 50,000 CFM) are involved due to the cost |
| impregnated with buffing compounds can adhere | | | | of high voltage electrical equipment. Efficiency is |
| to collector elements plugging dust collector | | | | improved with increased humidity of the air |
| passages. Linty materials such as dust from | | | | stream as a change takes palce in the dielectric |
| textile opener, picker and napper will adhere to | | | | properties of the dust. Heavy concentrations, on |
| certain types of collector surfaces or elements. | | | | the other hand, cause a reduction in collection as |
| Abrasiveness of many materials in moderate to | | | | the space chatge on numerous particles blankets |
| heavy concentrations such as dust from sand | | | | the corona effect from the electrode. |
| blasting will cause rapid wear particularly on dry | | | | Electrostatic precipitators have been extensively |
| type centrifugal collectors. Particles size and shape | | | | used in high temperature gas cleaning from |
| will rule out certain collector designs. The | | | | equipment such as blast furnaces, open heart |
| parashute shape of particles such as "bees wings" | | | | furnaces and central station pulverized fuel boilers. |
| from grain will "float" through centrifugal collectors | | | | The chemical industry has many applications |
| due to their velocity of fall being slower than | | | | including sulfuric acids plants, carbon black, cement |
| much smaller spherical particles of the same | | | | kilns and soda sh from paper mill black liquor |
| specific gravity. Combustible nature of many finely | | | | furnaces. As voltage setting is close to the |
| divided materials will influence selection of | | | | spark-over potential, application is limited to |
| explosion proof dust collectors for such products. | | | | materials that are not explosive or combustible in |
| * Methods of disposal. | | | | nature unless the carrier gas stream is an inert |
| Methods of removal and disposal of collected | | | | gas. |