Issue link: https://www.e-digitaleditions.com/i/1292632
56 / October 2020 powderbulk.com PBE SUPPLIERS' TIPS What issues can occur with my outdoor dust collector during the changing seasons? C hanging seasons can present many challenges for outdoor dust collector operations. First, con- sider moisture, which can affect a dust collector in two primary ways. For non-insulated dust collectors, cooling weather will cause more heat loss through the collector's walls, which may lead to dew point excur- sions and moisture condensation from the conveying air onto the collector's walls or other internal compo- nents and bag filters. Free moisture inside the dust collector will mix with the collected dust and create a wet or muddy cake on the bag filters. This leads to operation at higher differ- ential pressures and could contribute to loss of convey- ing air throughout the system. Insulating the collector walls and, in some cases, installing heating elements on the hopper and collector's housing can help prevent this from happening. Seasonal changes may also affect the compressed-air system used for pulse cleaning pulse-jet dust collec- tors. Cold weather will reduce the temperature in the valves and associated tubing. If the temperature drops below the rated dew point of the compressed air, ice crystals can form in the valves and tubing that will prevent the pulse-cleaning system from operat- ing properly. Installing a dryer on the compressed-air system can reduce the dew point to a level below the lowest expected ambient temperatures and prevent ice formation within the system. Michael Maxwell, engineering manager, Sly LLC, 440-891-3200 C ondensation in the dust collector. Water vapor in the air condenses into water droplets if the dew point or saturation temperature in a dust collector is lower than the air temperature. Water droplets and dust build up and form a coating on filter media. This causes bags and cartridges to plug, making cleaning them difficult. It also causes high pressure drop across the dust collector, loss of suction, and shorter filter life, thus increasing maintenance costs. To prevent condensation, the temperatures in a dust collector should be 40°F higher than the dew point. This could be achieved by: • locating the dust collector as close to the working station as possible; • bleeding warm air into the dust collector to keep temperature above the dew point; or • insulating the dust collector and inlet duct. Dust collectors made of heavy-gauge metal (7 and 10 gauge) that are powder-coated inside and out tend to provide better performance for condensation challenges. Moisture in the compressed-air supply. This typi- cally occurs if the dust collector system isn't equipped or sized with the proper air dryer and solenoid valve heater. Moisture will enter cleaning systems made up of solenoid and diaphragm valves and affect their per- formance, causing improper pulse-filter cleaning. This could cause premature cartridge or bag filter plugging while increasing pressure drop across the dust collector, shortening filter life. All these factors will contribute to increased maintenance costs. In freezing cold environ- ments, moisture in compressed-air lines could cause the solenoid valves to freeze, making them function improp- erly. Therefore, without proper pulse cleaning, cartridge or bag filters will plug prematurely and shorten filter life, increasing maintenance costs. The dust collector manufacturer should recommend a proper air dryer and solenoid heater to prevent these issues from happening. Malfunctioning airlock (if provided) on dust col- lector discharge. This could happen in very low tem- peratures with dust that has a high moisture content. Dust in both the hopper and in the airlock between blades and housing can build up until it becomes a frozen-solid cake, preventing the airlock from working. One remedy for this rare occurrence is to insulate and heat the dust collector hopper and airlock. Bes Blentic, Canada sales manager, Camfil APC, 877-441-5215 Moisture will enter cleaning systems made up of solenoid and diaphragm valves and affect their performance, causing improper pulse- filter cleaning.