b'Reference Information / Filter Bag Change Out TipsBaghouse Start Up Cleaning ProblemsAll the hard work involved with re-bagging a dust collectoron Pulse Jet Collectorscan be ruined in minutes by an improper start-up. The first resource to go to for detailed start-up instructions isPulse jet collectors first and foremost need a clean dry the baghouse manufacturers (OEM) documentation. Incompressed air source. Many problems can be traced back the absence of the original documentation, following areto the presence of either oil or water in the compressed some guidelines. Filter bags, generally speaking, performair stream. If this contamination is repeatedly sent back at their lowest efficiencies when new. They are also mostinto the filter bags both the bags and the cleaning system susceptible to being damaged when new. The build upwill suffer. Cleaning off line is preferred but not necessary. of a proper dust cake offers protection and increases theThe setting of duration and frequency is critical for proper collection efficiency of the filter. To aid in protecting thecleaning and dust cake management. The desire is to bags at startup pre-coating the bags with a specific dustcreate a sharp fist of air that moves in a wave down the agent such as Pre-Guard (see page 24) is recommended bag. Typical pulse durations should be around .15 seconds. .Cleaning intervals (frequency) are difficult to optimize to one While pre-coating and at initial start up the operatingvalue setting. For this reason the use of clean on demand velocity of the gas stream must be reduced below thetechnology has been adopted as best practice. Here a typical running values. This will allow the dust cake to formPhotohelic or Digihelic pressure gaugeis installed properly and not drive particles into or through the filter.to monitor the pressure drop across the baghouse. When Allow the dust cake build-up to cause a noticeable increasethe upper setting is reached the cleaning process will in the differential pressure (1-2). Special considerationcontinuously loop until the baghouse improves flow enough should be given to the startup and operation of a hotto reduce the pressure drop to the low set point. It will then baghouse. These are units that run around the mid 200Fshut down until the upper value is reached, cleaning only and higher. The concern here is condensation that isas required. This translates into both longer bag life and created when passing through the dew point. Pre-heatingenergy savings due to better management of compressed these hot baghouses using clean fuels such as natural gasair. Sequential cleaning of rows should be programmed to prior to going on line is best. clean every other row to reduce the re-entrainment of sub-micron dust onto the adjacent bag. Running StateOnce the collector has reached a steady state youShaker Collector Cleaningshould see a noticeable improvement in pick up and aShaker collectors have been around for a long time. The lower differential pressure. A good rule of thumb is to becleaning process is similar to shaking out a throw rug. operating in the 3-5 delta P range. Mechanical grids or bars at the top of the baghouse oscillate rapidly to create a shaking motion. This dislodges the dust cake into the hopper. As with other types of filters the breaking in (seasoning) of the new filter bag is critical. Be certain to turn off the cleaning circuit during the initial start up of the collector. This will allow a proper dust cake to form and build up protection for the filter media. Proper bag length adjustment plays a big role in cleaning. Too slack a bag and the bag will not clean down. Too tight and the strain on the seam will cause leakage through the sewing needle holes. As bags can stretch with use, a secondary adjustment of the shaker bars may be required after the break-in period.28 www.standardfilter.com1.800.634.58371.760.929.8559'