Particle drainage

To correct na unfavorable situation often requires an adjustment to the slurry characteristics rather then modification of the separation device. Increasing solids particle drainage characteristics via size enlargement techniques, conoenrmiing the sluny, heating the slurry, nadfor re arriving "fines" is the usual approach. 

Because gravity is too weak to be used for removal of cakes in a gravity side filter (2), continuously operated gravity side filters are not practicable but an intermittent flow system is feasible in this arrangement the cake is first formed in a conventional way and the feed is then stopped to allow gravity removal of the cake. A system of pressure filtration of particles from 2.5 to 5 p.m in size, in neutralized acid mine drainage water, has been described (21). The filtration was in vertical permeable hoses, and a pressure shock associated with relaxing the hose pressure was used to aid the cake removal. 

Dispersion at temperatures of 90—110°C is a common final step io European mills processiog wax-coated old cormgated containers. Dispersion temperatures less than 90°C are reported to reduce wax particle size to improve pulp drainage properties on paper machines while improving paper strength (45). Dispersion has been used to reduce hot-melt adhesive, plastic coating, and asphalt particle size. These low density particles can then be removed from the pulp by flotation (46). 

Equipment. Centrifugation equipment that separates by density difference is available in a variety of sizes and types and can be categorized by capacity range and the theoretical settling velocities of the particles normally handled. Centrifuges that separate by filtration produce drained soflds and can be categorized by final moisture, drainage time, G, and physical characteristics of the system, such as particle size and Hquid viscosity. 

A conveniendy expressed coordinate for plotting filtration performance is the drainage number, jwhere d is the mean particle diameter in... 

Water leaves the field either as surface mnoff, carrying pesticides dissolved in the water or sorbed to soil particles suspended in water, or as water draining through the soil profile, carrying dissolved pesticides to deeper depths. The distribution of water between drainage and mnoff is dependent on the amount of water appHed to the field, the physical and chemical properties of the soil, and the cultural practices imposed on the field. These factors also impact the retention and transformation processes affecting the pesticide. 

Aerosols reach the alveolar space depending on their particle size and physico-chemical characteristics. Small particles that reach the alveiilar region (see Sections 2.3.7 and 3.1.1) may reach the circulation through the lymphatic drainage of the alveolar region. 

Operating and Maintenance Costs mechanical details must account for the peculiarities of the system fluids (coking, suspended particles, immiscible fluids, etc.) and accommodate the requirements for drainage, cleaning (chemical or mechanical), corrosion, etc., in order to keep the daily costs of operation and downtime to a minimum. 

Provide sufficient depth of froth to allow drainage of entrained particles to take place. 

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