Rock Products

APR 2018

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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Page 20 of 67 ROCK products • April 2018 • 19 • Clay content. • Particle size distribution (very coarse, very fine). • Particle shape. • Particle chemistry, pH, temperature. Types of Filter Presses There are two main categories of filter press types. Those categories are Overhead Beam and Side Beam. Each type of press has its own advantages and disadvantages depending on the user's needs. Overhead Beam (OH) – Filter plates hang from overhead beams. •  Filter cloth change is easier because the overhead beam doesn't obstructed access to plates while they are in place on the press. •  Easier access for cloth washing and inspection, due to wider plate openings. •  Dynamic loads are typically isolated from the beams of the press using tension shafts in various configurations. Side Beam (SB) – Filter plates hang from side beams. • High speed cake discharge systems available. • Plate shaking systems aid in cake release. • Suitable for portable applications. •  Automated rain style or one-by-one high pressure cloth washing systems available. Properly Sizing a Filter Press Poor planning in sizing and design can cause unwanted wear problems. If under sizing occurs, it can result in high inlet velocities that cause excessive wear on the feed pumps, feed piping, filter clothes and, eventually, filter plates. Sites should select filter cloth styles and material based on inlet velocity to ensure they have selected the best material that will last the longest. Also, take into consideration costs to replace worn or torn filter cloths. Another problem undersized filter presses face is excessive opening and closing speed resulting in high wear and tear on mechanical components. Along with sizing, testing your slurry is imperative to select the filter press best for optimal performance and low maintenance cost. Placing a Filter Press Where is the filter press going to go? Just as important as the sizing, the location of the filter press is also an important factor. When deciding on the site location of a filter press, several factors should be taken into consideration: • Thickener/clarifier location. • Slurry feed storage tank location. •  Storage space for dewatered cake material below the press or for a conveying system. • Gravity flow of filtrate water away from the filter press. • Clearances required for replacing components. • Ability to deliver components/material to the filter press. • Lift capabilities designed to meet the specific tasks. Walkways, railings, harness tie-offs and access platforms are important design considerations incorporated to optimize safe operation and maintenance activities. Designers that are working with typical polypropylene filter plates and stan- dard cloth media should consider roof and side enclosures to prevent harmful damage cause by prolonged exposure to the sun's UV radiation. Ultimately, regardless of the filter press type and size, close cooperation with the end user, facility engineer and OEM will achieve a properly designed facility that facilitates good, safe maintenance practices. What Needs Maintenance on a Filter Press? Like any piece of equipment in your operation, filter presses require maintenance. When maintenance and inspection checks are performed regularly, your filter press can work at its best. Maintenance and inspection tasks to the filter cloth, plate, hangers, power unit and opening mechanism are all-important. Below are some helpful things to remember when inspecting your filter press. Filter Cloth Maintenance •  Should be checked for tears and rips at least once per shift. • Should be checked for cleanliness at least once per week and washed as needed, ensuring material does not build up between filter plate and filter cloth. •  An automatic wash system can be installed on applications that require frequent washing. Filter Plate Maintenance • Should be checked weekly or if filter cloths tear or rip for wear.

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