Pits & Quarries
Martin Engineering’s washbox conveyor belt cleaner
By Andrew Macklin
June 17, 2016 – Martin Engineering has introduced a secondary cleaning system that removes nearly all of the carryback left on a belt, including adhesive materials and fines lodged in surface divots and valleys. The Martin WashboxT Cleaning System combines water spray and secondary cleaning blades in an enclosed and self-contained unit, draining residue safely away from the work area. Operators who have installed the system have drastically reduced dust and spillage from carryback, leading to a safer workplace and longer belt life with considerably less downtime.
In operations conveying solid material, normal belt wear can yield valleys and depressions on the belt. Dust and fines that get into these blemishes remain after passing under primary and secondary belt cleaning blades, and become dislodged by shaking from return idlers, causing excessive dust and spillage. Water makes bulk material easier to remove by softening it, keeping the cleaner blades free from buildup and extending blade life by minimizing thermal breakdown due to frictional forces.
Available in two configurations, a Dual Cleaner System and a Single Cleaner System, the units are mounted on the conveyor frame directly after the return idler to ensure belt alignment throughout the cleaning process and to allow proper time for moisture evaporation on the return trip. Passing through a powder coated steel box with top rollers, the belt is gently washed by spray bars equipped with 10 to 30 nozzles delivering 5 to 60 psi (.34 to 4.14 bar) of pressure, using 5 to 54 gpm (20 to 204 L/min) of potable or non-potable water. The belt is then scraped clean by a polyurethane blade and/or a urethane squeegee blade, set on a tensioner for a tight and consistent blade-to-belt seal. Residue drains safely through an outlet funnel below the box, which can lead to a disposal unit or a settling pond/vessel for introduction of material back into the process.
Built for heavy to medium duty applications, the Dual Cleaner System is equipped with three rollers, four spray bars, two Martin Inspection Doors and two polyurethane secondary cleaners. Recommended for use behind a primary pre-cleaner on the face of the head pulley, the color-coded, high-performance urethane secondary cleaners can be specified for acidic or high-temperature materials. Optional tungsten carbide or stainless steel tips increase the effectiveness and durability of the blade against difficult or rocky carryback. The cleaner system can be specified from 30 – 60 inches (762 – 1524 mm) in length and 44.4 to 53 inches (1129 to 1350 mm) in height, and fits on most conveyor frames by adding approximately 17 inches (432 mm) to belt widths of 18 to 84 inches (457 to 2133.6 mm).
The Single Cleaner System houses a roller, a secondary blade and a spray bar, which are accessed by an inspection door housed on either side of the enclosure. Intended for tight-fitting spaces on light to medium duty applications, the compact unit is 15 inches (381 mm) long and can be specified from 34 to 42.2 inches (864 to 1072 mm) in height. The total width of the unit can be determined by adding 17 inches (432 mm) to the belt width of 18 to 48 inches (457 to 1219 mm). Recommended for use in tandem with a pre-cleaner, operators have found these units work well for both indoor and outdoor applications where walkways need to be kept free of clutter and pooling.
Operators concerned with the amount of moisture remaining on the belt have the option of adding a squeegee roller, which has proven to effectively address wet carryback. Set between top rollers, it lifts the belt slightly and “flattens” the layer of water on the surface from an average of 50 microns in thickness to 20 microns. This allows the water to better evaporate during its return, particularly on shorter conveyors.