Working Principle
The dust collector consists of a hopper, upper box, middle box and lower box. The upper, middle and lower boxes adopt compartment‑divided structure. During operation, dust‑laden gas enters the hopper through the air inlet duct. Coarse dust particles fall directly to the bottom of the hopper, while fine dust particles turn upward with the airflow into the middle and lower boxes. Dust accumulates on the outer surface of filter bags. The filtered gas flows into the upper box, passes through the clean‑gas manifold and exhaust duct, and is discharged to atmosphere via exhaust fan.
For ash cleaning, the clean‑gas outlet duct of the corresponding compartment is cut off first so that no airflow passes through the filter bags in this compartment (compartment off‑flow ash cleaning). Then pulse valves are opened for pulse jet ash cleaning with compressed air. The closing duration of cut‑off valves is long enough to ensure dust stripped from filter bags settles down into the hopper after jetting. This prevents stripped dust from re‑adhering onto adjacent filter bags with airflow, achieving thorough ash cleaning of filter bags. An programmable controller performs full‑automatic control over exhaust valves, pulse valves and ash discharge valves.
Technical Parameters
Product Features
1. This dust collector adopts compartment off‑flow pulse‑jet ash‑cleaning technology, which overcomes the drawbacks of conventional pulse dust collectors and compartment reverse‑blow dust collectors. It delivers strong ash‑cleaning capacity, high dust removal efficiency, low emission concentration, low air leakage rate, low energy consumption, low steel consumption, small footprint, stable and reliable operation and favorable economic benefits. It is suitable for purification of dust‑laden gas and material recovery in metallurgy, building materials, cement, machinery, chemical, power and light‑industry sectors.
2. Thanks to compartment off‑flow pulse‑jet ash cleaning, thorough ash cleaning can be completed by one single jet. Therefore ash‑cleaning cycle is extended, ash‑cleaning energy consumption is reduced and compressed‑air consumption is greatly cut down. Meanwhile, fatigue stress on filter bags and pulse valves is mitigated correspondingly, which multiplies service life of filter bags and valve discs.
3. Maintenance and bag replacement can be carried out compartment‑by‑compartment without shutting down the system fan while the system keeps running normally. Elastic expansion rings are used at filter bag openings for excellent sealing performance and firm mounting. Polygonal filter bag cages reduce friction between bags and cages, prolong filter bag service life and facilitate bag removal.
4. Upper bag‑pulling design is adopted. During bag replacement, after pulling out the cages, dirty bags drop into the hopper at the lower part of box and are taken out through manholes, which improves bag‑replacing working conditions.
5. The box is designed for high air tightness with reliable sealing. Access doors are fitted with premium sealing materials. Kerosene leak‑detection is implemented during manufacturing to achieve extremely low air leakage rate.
6. Compact layout of inlet and outlet ducts brings low airflow resistance.
Dust Collector Selection
1. Selection of Filtration Velocity
Filtration velocity is a key factor for dust collector selection. It shall be determined according to properties of smoke/dust, application scenario, dust particle size, viscosity, gas temperature, moisture content, dust concentration and filter media types.
Low filtration velocity (≤1 m/min) is recommended for fine dust particles, high temperature & humidity, high concentration and high viscosity. Higher velocity can be adopted for other conditions, generally not exceeding 1.5 m/min. For coarse‑particle, normal‑temperature, dry, non‑viscous dust with extremely low concentration, filtration velocity of 1.5‑2 m/min is acceptable.
When selecting filtration velocity, the net filtration velocity under condition of one compartment out of service (during ash cleaning) shall not exceed the above‑mentioned values.
2. Filter Media
Filter media shall be selected according to temperature, moisture content, acidity‑alkalinity of dust‑laden gas, as well as dust viscosity, concentration and abrasiveness.
For low‑moisture and non‑acid conditions, select media based on gas temperature:
- At ambient temperature or ≤130 °C: 500‑550 g/m² polyester needle‑punched felt is commonly used.
- Below 250 °C: Aramid Nomex needle‑punched felt, 800 g/m² fiberglass needle‑punched felt, 800 g/m² double‑weft fiberglass fabric or FMS high‑temperature filter media. (Fiberglass shall not be used for fluorine‑containing gas).
For high moisture content and high dust concentration, water‑&‑oil‑repellent filter media (anti‑condensation filter media) or membrane‑laminated filter media (substrate shall be water‑proof treated needle‑punched felt) are preferred.
For acid‑alkaline dust‑laden gas ≤190 °C: Ryton (PPS) needle‑punched felt is widely applied.
For gas temperature ≤240 °C with moderate acid‑alkali resistance requirement: P84 (polyimide) needle‑punched felt is selected.
For flammable and explosive dust‑laden gas: anti‑static polyester needle‑punched felt shall be used. For flammable‑explosive gas with certain moisture content: water‑proof, oil‑repellent and anti‑static (three‑proof) polyester needle‑punched felt is required.
3. Controller
PLC microcomputer programmable controller is adopted for ash‑cleaning control of long‑bag pulse dust collectors, offering three control modes: constant‑pressure (automatic), timed (automatic) and manual.
- Constant‑pressure control: Controlled by preset pressure difference. When pressure difference of dust collector exceeds set value, all compartments perform ash cleaning sequentially automatically.
- Timed control: According to preset time interval, all compartments complete one round of sequential ash cleaning every ash‑cleaning cycle.
- Manual control: Operate sequential full‑compartment ash cleaning or independent ash cleaning for single compartment via local operation cabinet.
Control mode is subject to customer selection. Timed control is supplied by default if no special requirement from customers.
