Airvate Blog

  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...

  When doing calculations, designing, and/or on-site work, we have to figure out which standard and code (federal, state, local) we will follow.   EPA and Permits EPA Title V Operating Permits (EPA) National Emission Standards for Hazardous Air Pollutants (NESHAP), Rule 6X for metalworking operations (EPA) Method 22: visual determination of fugitive emissions from material sources (EPA) Method 9: Visual determination of the opacity of emissions from stationary sources NAAQS (National Ambient Air Quality Standards)  On-site Measurement OSHA Technical Manual (OTM) Section II: Chapter 3, on-site Measurement (EPA) Method 22: visual determination of fugitive emissions from material sources (EPA) Method 9: Visual determination of the opacity of emissions from stationary sources Airborne Contaminants Cal/OSHA Title 8 Section 5155 - Airborne Contaminants OSHA (CFR, Title 29,1910) and Subpart Z - Toxic and Hazardous Substances OSHA 3348-05: Guidance for the Identification and...

  I happened to see a crushed filter cartridge when on-site. Normally, it is hard to see one, as they are always thrown into a Toter quickly and stealthily before someone notices. Though crushed, it still looks cool.  A crushed filter cartridge (1) A crushed filter cartridge (2)

This blog post consists of 4 sections 1. Brief on the Ferrous Sulfate Process (in a customer’s plant) 2. Introduction about Ferrous Sulfate and its hydrate state 3. Ferrous Sulfate in the product recovery system and problems it caused 4. Workplace exposure limit of Ferrous Sulfate Brief on the Ferrous Sulfate Process The Ferrous Sulfate heptahydrate bulk first goes through a dryer heated by hot air, then is lifted by a basket elevator to a cooling bed cooled by ambient air from the outside of the building. The exhaust airflows from the dryer and the cooling bed go to the same baghouse for product recovery . The old product recovery system was removed after years in duty and replaced, since the old one couldn’t meet the airflow requirement for the process. The old baghouse was made of carbon steel, while the new one was made of stainless steel which is more suitable for this moist and corrosive situation. Introduction about Ferrous Sulfate and its hydrate state Ferrous Sulfate,...