Push-in Fixed Coal Powder Sampling Device

I. Overview

Push-in fixed 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 grinding parts, changes in coal type and size, and the fineness of the coal powder will vary significantly, directly affecting the boiler combustion efficiency and increasing the cost of power generation. Therefore, regular sampling and testing of the 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 adjustments to the separator deflector opening are required to achieve the designed coal powder fineness.

II. Product Features and Structural Forms

This product uses compressed air as its power source to create a vacuum in the sampling tube, separator, and sampling bottle, thereby suctioning coal powder for sampling purposes. It also utilizes compressed air to blow clean the sampling tube, preventing blockages. The equipment is equipped with a pressure regulating valve for compressed air, which can adjust the pressure and flow of the compressed air to control the sampling speed and achieve isokinetic sampling, ensuring the coal powder collected is representative. The sampling tube features a push-in design, allowing it to be withdrawn from outside the coal powder pipeline when not in use, avoiding the impact of the coal powder airflow on the sampling tube and significantly extending its service life.

The push-in fixed coal powder sampling device mainly consists of the following components:

1. Sampling Tube — Inserts into the coal powder pipeline, with the sampling orifice facing the direction of the coal powder airflow, allowing coal powder to enter the sampling device. Multi-point sampling is conducted.

2. Sampling Bottle - Collects the coal powder samples separated by the cyclone separator for centralized storage and calibration purposes.

3. Cyclone Separator - Separates solid-gas mixtures by utilizing gravity and centrifugal force. Coal powder is flung to the wall by the rotating air stream and then falls back into the ash collector due to gravity. The separated gas rises along the central path to the top, where it exits through the vent at the top and is re-injected into the coal powder pipeline via a suction nozzle, thus achieving the separation of coal powder and gas.

4. Compressed Air Control Valve – Controls the on/off of compressed air.

5. Pressure Regulating Valve for Compressed Air – Adjusting this valve controls the pressure and flow rate of compressed air, governing the speed of sampling. It enables isometric sampling.

6. Vacuum 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.

7. Blowing valve – Compressed air enters the coal powder pipeline through this valve. Closing the valve will blow clean the entire sampling unit.

8. Transmission Mechanism - By摇动the transmission handle during sampling, the sampling tube can freely move in and out of the coal powder pipeline.

9. Sampling Valve – Opening this valve controls the sampling or blowback of the sampling tube to prevent clogging.

10. Sealing Device——Close this valve after the sampling tube is withdrawn from the coal powder pipeline to prevent the coal powder from leaking and contaminating the environment.

III. Working Principle

1. Sampling Principle

The push-in fixed 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 inserted into the coal powder pipeline with all valves open. As compressed air passes through the exhaust pipe and the ejector vacuum pump, its 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 isokinetic sampling, ensuring the coal powder sample is representative. (The compressed air pressure is generally not more than 0.1 Mpa.)

2. Blocking measures

During equipment operation, compressed air can be used to blow the sampling tube to prevent clogging by coal dust.

3. Abrasion Prevention Measures

During sampling, shake the transmission mechanism, slowly push the sampling tube into the coal powder pipeline, with the sampling port facing the incoming coal powder airflow, and open all valves to begin sampling. After sampling, shake the transmission mechanism again, pull the sampling tube out of the coal powder pipeline, place it outside, and avoid the impact of the coal powder airflow on the sampling tube to achieve anti-wear protection.

Section 4: Procedures

1. Sample collection

All valves are closed prior to sampling. First, open the compressed air control valve; adjust the compressed air pressure regulator based on the pressure gauge to reach the desired pressure range. Open the blow-down valve; open the sampling valve; open the sealing valve, shake the transmission mechanism; gently push the sampling tube into the coal powder pipeline; begin sampling, and then slowly withdraw the sampling tube from the coal powder pipeline once it is fully inserted. Close the sealing valve, the compressed air control valve, the blow-down valve, and the sampling valve; remove the sampling bottle; take out the coal powder sample and return the sampling bottle to its original position, ensuring the seal at the interface.

2. Blow-off

Open the compressed air control valve; close the blow-down valve; open the sampling valve; compressed air will blow through the sampling valve to sweep the sampling tube.

V. Performance Features

1. The product sampler is crafted from stainless steel, featuring a clean, compact design with a long overall lifespan.

2. Simple structure; flexible and smooth operation of the transmission mechanism; easy and convenient sampling.

3. Push-in design allows for single or multiple-point, uniform sampling; the coal powder samples collected are representative.

4. Use compressed air to blow clean the sampling tube to prevent coal dust from blocking it.

5. The sealing device fixed on the coal powder pipeline is tightly sealed, with no coal powder leakage at all, and does not contaminate the working environment.

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

7. One person can operate it, with minimal labor intensity required for the operator.

Section 6: Installation Requirements

Provide 0.4-0.6 MPa compressed air on-site.

2. The equipment is vertically mounted on the coal powder pipeline at an operating platform height of 600-1000mm, with an opening for installation holes. The fixed bracket is then welded onto the coal powder pipeline.

Section 7: Order Instructions

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

2. Operation Type (Electric, Manual).