Airvate Blog

  We were called in by a customer on one cold morning. Their dust collection system did not work when they turned on power as usual. First, we checked the ductwork to see if there was any dust accumulated inside from the sucking points, to the fan, then to the baghouse. It seemed the ductwork was not the problem. After being in the baghouse, the filtered air went back to the workshop. Then we opened the access door of the baghouse hopper, and what we saw showed us the problem: it was packed with wood dust (Figure 1).  Figure 1 baghouse hopper packed with wood dust  Later, the access door on the clean side of the baghouse was opened, and one bag was taken out, it was very clear that the dust even accumulated between bags (Figure 2). Figure 2 dust clogged up between bags After the dust was removed from the baghouse, the system was turned on. In the first 20 minutes, the baghouse was warmed up without dust loading.  When this happened, the daytime temperature outdoors w...

  In a periodic test of a baghouse dust collection system, the PD compressor’s belts were found almost worn out, though still running doggedly. The PD compressor supplies compressed air of about 8 psi to the low-pressure, high-volume pulse cleaning system of the baghouse. The belts had to be replaced. Per the model number on the old ones, the customer bought a pair of new ones, NAPA A38. Belt replacement for this PD compressor The alignment of the sheaves was checked first; it was good. The sheaves and their inner faces were cleaned up and inspected; they were fine. The motor base has a jacking bolt, so it is easy to adjust the position of the motor. The new belts were rotated by hand for a couple of rounds to make sure they sat in the groove properly. We then measured the span-length of the belt and the sheave diameter, read the motor RPM, and took the V-belt tension table by Browning as a reference to decide the deflection force of the belt as 6 pounds.  After the new belts ...

  In a periodic test of a baghouse dust collection system, dye test for leak detection was done to the baghouse by following the test procedure. The system collects wood dust, and the bags were installed 4 years ago. The air after the baghouse is recirculated back to the workshop to save energy, especially in winter. The dye test easily found glowing spots on some bags adjacent to the tubesheet with the help of a black light wand (Figure 1&2) . These spots were thought to be caused by the bleed-through of the green dye powder; they were not indicators of broken bags.  We put the dye test results in the comprehensive report for this periodic system test and explained our concerns to the customer.  Figure 1 Glowing spots under black light on bags, image 1 Figure 2 Glowing spots under black light, image 2 Leak Test, Air Balancing, Trouble-shooting, and System Evaluation services by Airvate Dye test for bag/cartridge leak  Dust collection system and industrial ventil...

  When we did a periodic test on a baghouse dust collection system, an abnormal noise from the airlock got our attention. The baghouse is equipped with a low-pressure, high-volume pulse cleaning mechanism.  After carefully studying, we found that the airlock’s rotation was interrupted each time the cleaning pulse was released, and consequently the airlock made noise.  We took off the chain cover, and a slack chain came into view (Figure 1 & 2). Apparently, the shaft of the gearbox reducer moved gradually closer to the airlock body shaft after years of operation because the mounting bolts of the reducer were not tight enough originally.  Because the airlock is a slow running device, we adjusted the gear reducer position and set the slack of the chain to 5% of the center to center distance of the shafts. After this was done, the airlock went back to normal.  Figure 1 Slack chain on the airlock, image 1 Figure 2 slack chain on the airlock, image 2 For compariso...

a magnehelic pressure gauge without a pointer When we audited a baghouse dust collection system, we saw this abandoned Magnehelic pressure gauge without a pointer in situ for the purpose of decoration only. Actually, it is very normal to see a malfunctional gauge on-site, for reasons such as mechanical vibration, pressure pulsation, elevated temperature, pressure differential out-of-range, connecting-hose clogging, mishandling and abuse, etc.  For a pressure gauge to lose its pointer is not uncommon either. Mechanical vibration is the major reason the connection of the pointer loosens and consequently drops to the bottom of the gauge housing.  The gauge in the above picture was installed on the support frame of the baghouse together with a differential pressure transmitter. We guess abnormal vibration caused by the baghouse operation on the whole support frame failed the gauge, or maybe the connection of the pointer was loose even before it was installed on-site. Magnehelic Di...

  When on-site, I happened to see a set of unused cyclones. Though rusted by wind and rain, they were still showing off their sturdiness under the clear sky.  Actually when travelling around from state to state, I saw some unused cyclones like this one too. I think they are a kind of relic preserved by the family and like a statue to signal the pride of the family. a set of unused cyclone under clear sky a set of unused cyclones, still looks sturdy

  We were called in to do a leak test on a cartridge collector. It had visible dust emission just out of the stack.  With the system running, fluorescent powder was added to the dirty side of the cartridge filter. The collector was then shut down, and access doors were opened. Broken gasket seals ( Figure 3 & 4 ) and one leaking cartridge with the help of black light ( Figure 5 ) clearly came into view. Figure 1 Dirty side of the collector Figure 2 Dirty side of the collector Figure 3 Broken and shrunk gasket Figure 4 Broken gasket Figure 5 Leak detected in a cartridge with the help of a black light After the leaky cartridge and the broken gaskets were replaced, the cartridge collector worked normally again.  Later, a dust detector paired with a tower light alarm was installed on the ductwork behind the dust collector. Any regular maintenance program for your baghouse/cartridge collector should include periodic Leak testing. This maintenance task helps to detect compr...