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I. Overview

Retractable arm coal powder sampling device, a specialized equipment for coal powder sampling on the primary air conveying pipeline of a positive pressure straight blowing coal powder system. During the daily operation of the coal mill, the wear of the coal mill grinding parts, the change in coal type and size, and the variation in coal powder fineness can significantly affect the boiler combustion efficiency, increasing the cost of power generation. Therefore, regular sampling and testing of coal powder fineness is necessary. When the coal powder fineness exceeds the designed value, timely adjustments or replacements of the coal mill grinding parts or the adjustment of the separator deflector door opening are required to achieve the designed coal powder fineness.

Section 2: Product Features and Structural Styles

This product utilizes compressed air as power to create a vacuum in the sampling tube, separator, and sampling bottle, thereby suctioning coal powder for sampling purposes. It also employs compressed air to sweep the sampling tube, preventing blockages. The equipment is equipped with a pressure regulator for compressed air, which can adjust the pressure and flow to control the sampling speed and achieve isokinetic sampling, ensuring the collected coal powder is representative. The sampling tube features a concealed arm design, remaining vertically hidden outside the coal powder pipeline when not in use, thus avoiding the impact of coal powder airflow on the tube and significantly extending its service life.

The concealed arm coal powder sampling device mainly consists of the following components:

1. Sampling Tube – Inserted into the coal powder pipeline, the sampling port facing the incoming coal powder airflow, with coal powder entering the sampling device through it. Multi-point sampling is conducted.

2. Sample Bottles - Collect and store the coal powder samples separated by the cyclone separator for calibration purposes.

3. Cyclone Separator — It separates solid-gas mixtures, where coal powder is spun to the wall due to gravity, and then falls into the ash collector. The separated gas rises along the middle route to the top, exits through the top outlet, and is re-injected into the coal powder pipeline via a suction nozzle, achieving separation of coal powder and gas.

4. Quick-connect couplings for easy assembly.

5. Inlet short pipe - for connecting compressed air.

6. Compressed Air Control Valve - Controls the on/off switch for compressed air.

7. Pressure Reducing Valve for Compressed Air – Adjusting this valve controls the pressure and flow rate of compressed air, thereby regulating the sampling speed. It enables uniform sampling speed.

8. Suction Pump - Driven by compressed air, it creates negative pressure in the sampling tube, cyclone separator, and sampling bottle, allowing coal powder to smoothly enter the cyclone separator for solid-gas separation.

9. Sweep Valve - Compressed air enters the coal powder pipeline through this valve.

10. Sampling Operation Rod - Operate this rod to extend or retract the sampling tube.

11. Sampling Valve — Open or close this valve to control sampling or blowback of the sampling tube to prevent clogging.

12. Shell Body — Installed on the coal powder pipeline, the sampling tube is concealed within it when no sampling is taking place.

Section 3: Working Principle

1. Sampling Principle

The concealed arm coal powder sampling device is developed by utilizing the principle of negative pressure suction and cyclone separation to extract the gas-powder mixture from the coal powder pipeline and achieve solid-gas separation. During the sampling process, the sampling tube is extended into the coal powder pipeline, with all valves in the open position. As compressed air passes through the exhaust pipe and the ejector vacuum pump, the jet action inevitably creates negative pressure in the cyclone separator, sampling tube, and sampling bottle components, prompting the gas-powder mixture in the coal powder pipeline to flow into the sampling device via the sampling tube. The gas-powder mixture undergoes solid-gas separation in the cyclone separator, with the separated coal powder falling into the sampling bottle below the separator, while the gas is suctioned away by the compressed air and returned to the coal powder pipeline. The entire operation process does not produce pollution in the workplace. Before sampling, adjusting the pressure regulating valve for the compressed air allows for uniform sampling speed, ensuring that the collected coal powder sample is representative. (The compressed air pressure generally does not exceed 0.1 Mpa.)

2. Anti-blocking measures

During the equipment operation, compressed air can be used to blow clean the sampling tube to prevent it from being clogged by coal dust.

3. Abrasion Prevention Measures

When not sampling, the sampling tube is concealed within the housing, positioned outside the coal powder pipeline. During sampling, pull the sampling operation lever to extend the sampling tube into the coal powder pipeline, with the sampling port facing the coal powder airflow. Open all valves to begin sampling. After sampling, pull the sampling operation lever again to retract the sampling tube back into the housing, positioning it outside the coal powder pipeline to prevent the coal powder airflow from washing the tube, thereby achieving anti-wear protection.

Section 4: Procedures

1. Sample Collection

Prior to sampling, all valves are in the closed position. First, open the compressed air control valve; adjust the compressed air pressure regulator based on the pressure gauge to bring the compressed air pressure within the required range. Move the sampling operation lever; extend the sampling tube into the coal powder pipeline; open the blow-down valve; open the sampling valve; begin sampling for 2-4 minutes; close the compressed air control valve, blow-down valve, and sampling valve; move the sampling operation lever again; retract the sampling tube into the housing; remove the sampling bottle; remove the coal powder sample and return the sampling bottle to its original position, ensuring the seal at the connection is secure.

2. Blowing off

Open the compressed air control valve; close the blow-off valve; open the sampling valve; compressed air will flush through the sampling tube via the sampling valve.

V. Performance Features

1. The product is made entirely of stainless steel, featuring a clean, compact design with a long overall lifespan.

2. Simple structure, no mechanical moving parts, maintenance-free. Sample collection is simple and convenient.

3. Employed multi-point, isokinetic sampling, the collected coal powder samples are representative.

4. Compressed air blow cleaning of the sampling tube can be used to prevent coal dust from blocking the tube.

5. Fixed securely on the coal powder pipeline, it ensures a tight seal with no coal powder leakage, thus posing no pollution to the working environment.

6. Place the sampling tube into the coal powder pipeline during use. After collecting the coal powder sample, it can be concealed outside the coal powder pipeline to avoid the erosion of the coal powder flow, ensuring a long service life.

7. One person operation, with minimal labor intensity for the operator.

Section 6: Installation Requirements

现场 requires 0.4—0.6 MPa compressed air.

2. The equipment is vertically or horizontally mounted on the coal powder pipeline at the operating platform level of 1000-1500mm, featuring an installation hole of 500×40mm (length×width) downward (specific dimensions are calculated based on the coal powder pipeline parameters), and the fixed shell is secured with a welding installation flange.

Section 7: Order Instructions

Provide the diameter and wall thickness of the coal powder pipeline when placing an order.

2. Operation Mode (Electric, Manual).

Section 8: Model Description

Model: YBMF-XXX, where YBMF stands for the code for the concealed arm coal powder sampling device, and XXX is the diameter of the coal powder pipeline.