The coal powder sampler is a constant-velocity sampling device specifically for power plants, thermal power plants, and coal powder boiler pulverizing systems. It is used to obtain uniform and representative coal powder samples from the primary air-coal powder pipeline, for the detection of coal fineness, moisture content, ash content, and other indicators, guiding the boiler's optimized combustion and ensuring the economic and environmentally friendly operation of the unit.
I. Core Working Principle
Comply with the National Standard for Uniform Rate Sampling (GB/T 18511):
The air flow velocity at the gun mouth is consistent with that inside the pipeline for coal powder, to avoid flow rate discrepancies leading to false sampling of fine and coarse powder;配合 negative pressure suction / compressed air blowing to achieve point and full cross-sectional sampling, with strong representativeness of the sample.
II. Main Categories
By level of automation
Manual Push-Type Coal Powder Sampler: Manually push/pull the sampling gun, simple structure, low cost, suitable for small and medium-sized units
Semi-automatic Coal Powder Sampling Device: Electric telescopic sampling gun, reducing manual operation intensity
Fully Automatic Coal Powder Sampler: PLC controlled, automatically performs extension/retraction → isometric sampling → blowing → reset, with remote control capability, suitable for large-scale thermal power units
2. Installation and Usage Methods
Fixed: Permanently installed on a single coal powder pipeline for long-term, fixed-point sampling
Portable: Compact, mobile, multi-tube wheel for inspection and sampling rotation
Retractable/Extendable: During non-operation, the sampling tube is withdrawn from the pipeline airflow, significantly reducing erosion and wear.
III. Core Structure Composition
Sampling Gun / Sampling Probe: Wear-resistant stainless steel material, isometric sampling orifice design
Telescopic Thrust Mechanism: Electric / Manual, for probe insertion and withdrawal from pipe
Vacuum Extraction Components: Jet Water Extractor / Jet Gas Extractor, providing sampling power
Gas powder separator: Separates coal powder from compressed air, collects samples
Blow-off System: Compressed air blow-off pipes, anti-blocking and anti-dust accumulation
Control Box / Gauge: Differential Pressure Monitoring, Uniform Speed Regulation, Stroke Control
IV. Key Performance Features
Constant error ≤ ±5%, sampling results are accurate and reliable
Self-cleaning feature, no clogs, no dust accumulation
All stainless steel material, wear and temperature resistant, suitable for high-temperature coal powder gas flow
Easy installation, quick flange/casing-style pipeline connection
Fully automatic models can operate unattended and perform timed sampling.
V. Applicable Conditions and Scenarios
Applicable Medium: Coal dust + primary air mixed gas stream
Common Parameters: Air temperature ≤ 350°C, Pressure ≤ 0.25 MPa, Flow rate 10–30 m/s
Application Scenarios: Direct Blowing Pulverizing System, Intermediate Storage Pulverizing System, Coal Pulverizer Commissioning and Routine Inspection
Section 6: Key Selection Parameters
Coal powder pipeline nominal diameter DN
Medium Temperature, Operating Pressure, Air Flow Velocity
Sampling Method: Manual / Electric / Fully Automatic
Installation Type: Fixed / Portable, Flanged / Welded
Material Requirements: 304/316L Stainless Steel, Wear-Resistant Coating
