Airvate Blog

In the process of starting up a new baghouse dust collection system, we found this interesting pressure gauge on the PD blower; the blower was not turned on yet, but its pointer was sitting on the other side of the stop pin. Nobody knew how this happened and it had to be replaced.  If not carefully checked, the error was hard to spot. Figure 1 Pointer of the pressure gauge sits on the wrong side of the stop pin Leak Test, Air Balancing, Trouble-shooting, and System Evaluation services by Airvate Dye test for bag/cartridge leak  Dust collection system and industrial ventilation system Testing and Air Balancing Technical services: field survey and dust collection system audit / evaluation and trouble-shooting New system start-up Dust sample analysis Dust collector selection and sizing: baghouse, wet scrubber, cyclone, settling chamber, drop-out box, etc.

  When we inspect a dust collection system, we always work on the PD blower (positive displacement blower) if equipped with one. Figure 1 a PD blower with intake filter taken out Intake filter Nearly every time an intake filter was taken out,  it was dirty and covered with dust or dirt. Since the intake filter is normally shrouded inside of a cover, it is not visible and is forgotten or ignored easily by maintenance guys or other service contractors. If it is a paper or felt element, we will tell the customer when to replace it, or if it is a wire mesh element, we will clean it with lukewarm water, and if there is oil on it, we will wash it with mild detergent. Because of the tight clearances used in the design and manufacturing of the PD blowers, they require filtered intake air. Proper maintenance of the intake filter will help insure a long service life for the PD blower. Consequently, a clogged intake filter will cause poor performance and overheating of the PD blower. Her...

  One customer told us that their dust collection system had a very weak suction on the grinding process line, and we went to their workshop on-schedule to do troubleshooting.  Introduction of the dust collection system The dusty air from the plastic grinder first ran through a cyclone and the separated dust from the cyclone directly went back to the process; the airflow with fine particles from the cyclone went to a cartridge dust collector, and then the filtered air was released to outside of the building. Since the plastic dust is combustible, an explosion panel and a vent duct were installed on the dust collector, and a non-return valve on the ductwork just in front of the dust collector inlet. The cartridge dust collector was equipped with a pulse jet cleaning system controlled by a Photohelic pressure gauge. The Photohelic Gauge measures the Differential Pressure and provides the capability for “on-demand” cleaning in conjunction with a Timer Board. Troubleshooting proce...

  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...