Bags and cages are the heart of any fabric filter system.  Proper material selection, based on process conditions and emission guarantees, bag to cage fit and bag to tubesheet fit is essential for a system to operate properly.   If you are having short bag life, high pressure drop or not meeting emission limits then our technical experts can recommend the appropriate bag material.




Southern Environmental, Inc. can provide you with bags that ensure maximum filtration efficiency, cake release and durability.


Many variables affect the type of fabric needed for a specific system.  These variables include:


•  Temperature

•  Moisture Level

•  Particulate Size

•  Gas Stream Chemistry

•  Air-to-Cloth Ratio

•  Particulate Abrasiveness

•  Mechanical Factors, such as cleaning style, installation etc.


Use the chart below to assist in selecting the appropriate bag to meet your filtration system needs.



Proper support of your filter bags is critical for efficient cleaning and long bag life.  Over time, cages become corroded, which can cause wear and premature bag failure.   We can assist you in selecting the proper cage design, material and fit.


Filter cages are available in mild steel, galvanized steel, epoxy coated or stainless steel. If designing for a corrosive environment, multiple piece cages can be provided with dissimilar metals at the connecting point.



The recent advances in long bag technology necessitate the use of multiple piece cages.  The connection between cage pieces must be designed to withstand the rigors of installation and everyday operation without becoming a maintenance burden.  SEI offers several cage connection options.  We can replace your existing cages in-kind or assist you with an upgrade to the latest technology.





These cages are manufactured by pulling wire off a coil, through a straightening die and cutting it to precise lengths.  These individual stringer wires are then loaded into a magazine which maintains the exact spacing of the wire.  They are fed to the welding mandril and welded to the inside of the bottom pan. Spacer rings are then attached using digitally controlled resistance welding.  The top component is fixture welded to the tube to maintain finished cage length and assure proper alignment and installation.


The cage spacer rings are automatically manufactured by pulling wire off a coil, through a cutting die and around a coiling pin which forms the wire into an open ring.  Welding jaws grasp the ring and close the ends, applying pressure and introducing a precisely controlled pulsing current which fuses the ends into a continuous ring.  Statistical process control techniques monitor quality.  Standard and specialty cage tops are available.  Crimped bottom pans are available for mesh and welded bottom pans are available for rigid wire cages.





A venturi is an integral component of some pulse-jet collectors.  It directs the blast of compressed air into the center of the filter bag to prevent abrasion caused by misaligned blowpipes and turbulent airflows.  If venturis become damaged or worn, compressed air doesn’t gain the velocity required to effectively clean the filter bags.





Clamps are a necessary part of proper bag installation and are designed to increase bag life by decreasing the chances of clamp failure.  Clamps are manufactured in many sizes and are designed for use with raw edge top bags or cord bottom bags fitted on a thimble.


Before purchasing, you should consider the many reasons why clamps can fail: misapplication, misplacement, overtorquing and reuse of old clamps.




Pulse cleaning of the fabric filter bags is critical to maintain system pressure and facilitate smooth system operation.  Additionally, this cleaning extends the life of the bags by clearing the material from the bags prior to idling the system.  Replacement pulse valves are available as total units, rebuild kits or coil only.  Although other sizes are also available, typical pulse valve sizes range from 1.5 to 3”.  120 VAC or 24 VDC are the standard voltages supplied; however, other voltages are also available.  Various diaphragm materials are available as required for your process.




Pulse valve rebuild kits are available in various materials based on your process requirements.


Replacement pulse valve coils can be purchased separately.  120 VAC or 24 VDC are the standard voltages supplied; however, other voltages are also available.




Pulse valve hoses and hose clamps are available.  Standard hoses are 4” long with a maximum operating temperature of 200°F.  Hoses are constructed of aramid polyester wrapped Neoprene and have a working pressure of 178 psig.   Other lengths  and specifications are available.




The pulse timer board is an integral part of the bag pulsing system.  Pulse timer boards ensure proper cleaning of your baghouse. The operation times are adjustable and the number of outputs are 3, 10, 20 and 32.  The standard voltage is 120 VAC, other voltages are available.



The connection between the filter bag and tubesheet is critical to both environmental performance and bag life.  The integrity of this connection depends on tight tolerances for the bag, cage and tubesheet hole.   Corrosive flue gas will attack the tubesheet and, over time, the hole diameter tolerance will be lost.  SEI can supply and install replacement tubesheets that meet or exceed the original manufacturers specifications and tolerances.



Automatic purge valves are designed to eliminate moisture buildup in the compressed air header before entering the unit, causing corrosion and dustcaking on the top of bags.  This valve is located at the bottom of the air header assembly and connected to a pulse valve.  When the pulse valve fires, the valve opens a discharge port on the air header assembly, removing excess moisture




Quickly finding and replacing broken or leaking bags is critical to maintaining compliance with today’s strict emission standards.  It is also important to locate a broken bag before the dust can contaminate the clean side of adjacent bags, thereby causing premature failure.


SEI can provide fluorescent powder to be injected upstream of the baghouse.  The powder will take the path of least resistance and find its way to the source of the leak.  Some of the fluorescent powder will accumulate around the top of the leaking bag where the velocity is reduced, allowing fallout.


A blacklight is then used to locate the areas of accumulated powder.  The fluorescent powder glows brightly under the blacklight.  Once leaks are found and repaired, a second leak test can be performed using a different color powder to verify that all leaks have been eliminated.


Leak detection powder is available in a variety of colors.  It is important to select an appropriate color for your specific application and it is best to alternate colors for each round of testing.  One pound of leak detection powder is recommended for every 1000 square feet of filter cloth.


Pink - Appropriate for all industries

Orange - Should not be used where iron oxide is present.

Green - Generally good for all industries.

Yellow - Good for all industries except where high sulfur concentrations are present.


SEI can provide a complete leak detection kit, including powder, black light, charger and UV protection glasses.  SEI can also send one of our trained professionals to perform the leak check for you.





Precoat material is a dry, inert powder.  When introduced into the gas stream at the inlet of your baghouse it coats and conditions the fabric filters promoting maximum particulate collection efficiency and effectiveness.   Precoat material can be used as an initial control layer for start-ups to precondition fabric filters.  It can also be continuously injected into the gas stream to blend with the process dust to help collection efficiency.  The precoat material forms a uniform three-dimensional, porous dust cake that is ideal for efficient and effective baghouse operation.  Due to its multi-walled, curved structure of varying sizes and shapes, precoat material provides a naturally well balanced particle size distribution that promotes increased air flow, thus reducing differential pressure and energy costs for your baghouse.



•  Aids in collection efficiency while optimizing airflow.

•  Protects against blinding and plugging your fabric filters.

•  Inhibits sparks in the airstream due to its high melting point.

•  Absorbs damaging moisture, oils and hydrocarbons due to its chemically inert and neutral pH nature.


One pound of precoat material will cover over 22 ft2 of cloth with a 1/16” coating; compared with lime and flyash that will only cover up to 5 ft2 of cloth per pound.



Southern Environmental can provide all types of doors for precipitators, fabric filters and ductwork.


Our standard carbon steel doors resist harsh environments and hard wear, providing years of leak-free service.


We offer round and rectangular doors in various standard and custom sizes for your specific application.  Stainless steel doors are also available.



Door seals require regular inspection and replacement.  Over time, seals may shift, deform, become brittle or fail to seal properly due to warping of the door itself.


Stock material consists of a variety of quality door seals to meet the specific needs of any application.


High and low temperature caulking material is also available.


One tube of caulking material can cover a length of 25 feet.  (Expect to use an additional 10% on corners and splices.)



Southern Environmental’s removable top lid design incorporates the pulse header, pulse valves and blow pipes into the lid.  This allows for fast and safe maintenance, as the entire tubesheet is exposed and bags and cages can be immediately accessed without removing individual blow pipes once the lid has been lifted.  Our design also incorporates integral stacking legs so that the removed lid can be placed on top of an adjacent compartment without risk of damage to the pulse system.


SEI can repair or replace damaged top lids as well as retrofit them onto existing fabric filters.



Single point vibrating level probes (pictured left) are installed in the system to monitor reagent storage levels, material flow and hopper level.  These level probes are available for standard temperature duty (300°F) and higher temperature applications.  (One is used in the baghouse and one is used in the Ash Removal system).



To aid in moving the material out of the compartment hoppers, electro-mechanical and pneumatic vibrators are installed.  We can offer replacement units for use on your equipment.






Proper spray atomization is key to successful evaporative cooler operation.  Over time, nozzles can wear due to erosion and/or corrosion.  SEI can supply replacement nozzle tips, nozzles or entire spray lances to restore the evaporative cooler performance to its original design specifications.  The SEI spray lance design allows for in-place adjustment to ensure proper nozzle placement and spray direction.  Standard configurations are available in 316L stainless steel and 440 stainless steel. Other materials such as Hastelloy C276 and Inconel 600 are also available.




SEI can supply replacement hoses for connecting spray lances to the supply header.  Hose materials are selected to meet your site specific temperature, pressure and environmental requirements.




SEI can provide replacement pumps, control valves and actuators for your evaporative cooler pump system.  SEI also designs and builds our own pump skids and can provide an entire new pump skid designed to reliably supply the water and atomizing air required for optimum evaporative cooler performance.




Most air pollution control systems incorporate process dampers for flow control, compartment isolation or bypass.  Dampers can be actuated manually, electrically or pneumatically.  SEI can provide replacement parts, such as actuators, solenoids, limit switches, bearings, seals or linkage, for your existing dampers.  We can also supply complete replacement dampers to match your existing damper specifications, including size, flange, bolt pattern, pressure, temperature, flow and actuation.  Damper styles include butterfly (wafer), multi-blade louver, poppet and guillotine.




Expansion joints are utilized on both process gas duct and in process liquid (irrigation and flushing fluid) systems.  Expansion joints can be tailored to the application as required to exceed the original process conditions, thereby providing an equal or superior replacement to original equipment.  SEI’s engineering department can assist in determining failure modes to offer the optimum materials and construction in the full range of expansion joints to restore or improve the overall system performance.




Should your system fan require a replacement coupling, belts, bearings, shaft or other parts, our spare parts specialists can assist you in the supply of OEM replacement parts.  If your entire fan needs to be replaced or upgraded, our engineers can help you be sure that you are getting the right fan for the job.




For systems pneumatically conveying reagent for process gas conditioning, it is imperative the conveying air supply remain constant.  To protect your conveying air equipment, replace your inlet air filter.  We offer replacement filter elements for your specific equipment.




Our reagent feeders offer optimum flexibility should you require adjusting your reagent feed rates outside of the VFD range.  This can be achieved by swapping out the feeder screw and auger by a simple 1/4 turn of the auger and feed tube.





To keep your reagent feeder operating smoothly, replacement auger drive catridges are available through our spare parts department.




A clear reagent injection line is critical for maintaining dependable reagent injection.  Ambient air is pulled through the downspout filter and through the injection line.  Replacement air inlet filter elements are available through our spare parts department.

Corporate Headquarters:  6690 West Nine Mile Road, Pensacola, FL  32526   850-944-4475   apcsales@sei-group.com

Midwest Engineering Office: 921 Eastwind Drive, Suite 115, Westerville, OH 43081   614-259-6505