The filter bag cage is the internal support frame that keeps a pulse-jet filter bag fully open and cylindrical during operation. Without a properly fitted cage, the filter bag would collapse under suction and fail to function. LIMING manufactures precision cages in carbon steel, stainless steel, and galvanized finishes with round, oval, and star configurations.
In a pulse-jet baghouse, each filter bag is slipped over a wire cage — also called a bag support frame or skeleton. The cage provides the rigid internal structure that maintains the bag's tubular shape against the negative pressure (suction) of the dust collector fan. During pulse cleaning, the compressed air jet travels through the venturi at the cage top, expands the bag briefly outward from the cage, and dislodges the dust cake.
A well-manufactured cage is essential for proper baghouse operation. Cages with rough welds, sharp edges, or corroded wires can puncture or abrade the filter bag from the inside, causing premature failure. The cage's diameter must be precisely matched to the bag's inner diameter — too loose and the bag sags and folds; too tight and installation is difficult and bag stress is increased.
LIMING produces filter bag cages using automated resistance welding for consistent, smooth weld joints. Every cage is inspected for straightness, diameter uniformity, and burr-free surface finish. We supply cages as matched sets with our filter bags to guarantee proper fit and complete baghouse support.
The cage material must be compatible with the gas temperature and chemistry in your baghouse. Selecting the wrong material leads to rapid corrosion, cage failure, and filter bag damage:
| Material | Max Service Temp | Corrosion Resistance | Best For |
|---|---|---|---|
| Carbon Steel | 150°C | Low — requires coating | Low-temp, dry gas applications (raw mill, conveyor points) |
| Galvanized Steel | 180°C | Moderate — zinc coating protects | General-purpose, moderate moisture applications |
| Stainless Steel 304 | 250°C+ | Good — resists most acid gases | Kiln exhaust, coal mill, moderate acid gas |
| Stainless Steel 316 | 260°C+ | Excellent — Mo alloy resists pitting | Aggressive gas, high chloride, severe corrosion |
For cement plant applications, stainless steel 304 is the most common choice for kiln and coal mill baghouses where temperatures exceed 150°C or acid gases are present. Carbon steel with epoxy coating is adequate for low-temperature, low-moisture applications. Galvanized steel offers a cost-effective middle ground for moderate conditions.
Precision welding, material expertise, and complete baghouse supply.
Automated resistance welding produces uniform, burr-free joints that won't damage filter bags.
Carbon, galvanized, SS304, and SS316 — we match the cage material to your gas temperature and chemistry.
Cages and filter bags supplied as matched sets — guaranteed fit and optimal baghouse performance.
Venturi ejectors engineered for optimal pulse-air distribution and efficient bag cleaning.
| Parameter | Specification |
|---|---|
| Product Type | Filter bag cage / support frame |
| Material Options | Carbon steel, Galvanized, SS304, SS316 |
| Cage Types | Round, Oval, Star (multi-rib) |
| Diameter | 120 mm, 125 mm, 130 mm, 150 mm, 160 mm, 180 mm (custom) |
| Length | 2,000 mm – 8,000 mm (custom, sectional available) |
| Vertical Wire Count | 8, 10, 12, 16, 20, 24 (type and diameter dependent) |
| Wire Diameter | 3.0 mm – 4.5 mm |
| Horizontal Ring Spacing | 150 mm – 250 mm (per length and diameter) |
| Ring Wire Diameter | 4.0 mm – 6.0 mm |
| Venturi | Aluminum, carbon steel, or stainless steel ejector |
| Top Collar Style | Flange, snap-band, or flat (per tube sheet design) |
| Surface Treatment | None, galvanized, epoxy coating, electropolished (SS) |
| Welding | Automated resistance welding, burr-free |
| Lead Time | 7-20 days (stock sizes), 15-25 days (custom) |
Automated welding and rigorous inspection ensure every cage is straight, smooth, and dimensionally accurate.
Vertical wires and horizontal rings cut to length from the specified material and wire gauge.
Horizontal support rings rolled to the cage diameter with precise circumference control.
Automated resistance welding joins wires to rings — uniform, strong, and burr-free joints.
Galvanizing, epoxy coating, or electropolishing applied per material and application.
Straightness, diameter uniformity, weld quality, and venturi fit verified before packaging.