1. Introduction

The M6-29 coal powder centrifugal ventilation mechanism is single suction, with 6 models including No.12.5, No.13, No.14, No.15, and No.16.5, all of which are D-type transmission. The ventilation fan is made in two types: right rotation and left rotation. Looking at the fan from the transmission group, if the impeller rotates clockwise, it is called right rotation, represented by "right"; Counter clockwise rotation is called left rotation, represented by "left". The outlet position of the fan is represented by the angle of the air outlet of the casing. Both "left" and "right" can be made into six angles: 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, and 225 degrees. M6-29 coal powder centrifugal fan has high efficiency, flat performance curve, wear resistance, and stable operation. The impeller is made of manganese steel plate with wear-resistant coating, which extends its service life.

2. Structure

The structure of a coal powder centrifugal fan is mainly composed of an impeller, a casing, an air inlet, a transmission group, etc. 1. Impeller: There are 16 or 32 blades, with a forward curved shape. The blades, wheel cover, and disc are all made of 16Mn and have a wear-resistant layer. The impeller does not have a diffuser, and the peripheral speed can reach 140m/s. After the impeller is formed, it undergoes static and dynamic balance correction, so it runs smoothly. 2. Chassis: Composed of two parts, the rotor can be lifted upwards after disassembly for easy maintenance. The snail shell plate is made of 16Mn to improve wear resistance, while the rest is welded with ordinary steel plates to form a snail shell as a whole. 3. Air inlet: Made into a convergent streamlined overall structure, fixed on the inlet side of the casing with bolts. 4. Transmission group: composed of main shaft, bearing box, pulley, etc. The spindle is made of high-quality steel and is constructed as an integral box structure. Made by rolling, rolling is used to make lubricating grease for lubrication.

3. Characteristics

(1) In terms of performance, it can completely replace the old type of fan, and its efficiency reaches 81.2%, which can save a lot of electricity.

(2) 16Mn steel plate was used for the original materials (wheel cover, disc, blades), and wear-resistant coating was added to extend their service life.

(3) The transmission components (excluding the main shaft) are compatible with the old product, and the basic dimensions remain the same as the old product (except for the air outlet at 0 degrees).

(4) Due to the high total pressure coefficient of the fresh air fan, its original diameter was smaller and the circumferential velocity was also lower, thus improving the working stability of the fan.

4. Purpose

This fan is suitable for conveying coal powder in the coal powder system of 50-300MV power plant boilers, as well as for conveying other non corrosive gases, but the medium temperature should not exceed 250 degrees Celsius and the dust content should not exceed 85g/m3

5. Precautions

(1) The fan needs to be installed by professional personnel according to the prescribed procedures, and can only be put into production after a normal trial run.

(2) Before starting the fan, it is necessary to close the air door. After reaching normal speed, slowly open the air door until it meets the requirements to avoid motor failure due to excessive starting current.

(3) If any abnormal situation is found during the operation of the fan, it should be stopped immediately, the cause should be identified, and the fault should be eliminated before continuing to operate.

(4) The bearing box of the fan can be cooled by water, and the water pressure should not exceed 0.4Mpa. Due to different temperatures and seasonal variations in various regions, the water flow rate can also vary. Generally, the seawater volume can be considered as 0.5-1m3/h. At the same time, attention should be paid to the water quality to avoid scaling and blockage in the water channel, which may affect the cooling effect.

(5) If the impeller of the fan is worn out, it should be re balanced and corrected after welding repair.

(6) The bearing temperature of the fan should not exceed 80 ℃.

(7) The fan should be inspected regularly according to its usage.

(8) The operating speed of the fan shall not exceed the allowed operating speed, and it is not allowed to use pulley speed change.

(9) Lubricate the bearings with thin oil, and it is recommended to use N-32 mechanical oil.

(10) The vibration speed of the bearing box during normal operation does not exceed 6.3mm/s.

6. Performance parameter table