The 4-73 centrifugal fan is suitable for the ventilation and induced draft fan systems of 2-670T/h steam boilers in thermal power plants.

4-73 centrifugal fan:

Unless otherwise specified, the 4-73 centrifugal fan can be used for mine ventilation and general ventilation. The medium conveyed by the fan is air, and the higher temperature should not exceed 80 ℃. The medium conveyed by the induced draft fan is flue gas, and the higher temperature should not exceed 250 ℃. Before the induced draft fan, a dust removal device must be installed to minimize the dust content of the flue gas entering the fan. According to the general power plant usage, the dust removal efficiency should not be less than 85%.

Construction of 4-73 centrifugal fan:

The fan is mainly composed of an impeller, a casing, an air inlet, a regulating station, and a transmission part.

(1) Impeller: It consists of 12 angled blades welded to the middle of the conical front plate and the flat rear plate. Due to the use of wing shaped blades, the fan ensures high efficiency, low noise, and high strength. The impeller has undergone static and dynamic balance correction, ensuring smooth operation. The impeller structure of the ventilation and induced draft fans with the same machine number is the same;

(2) Shell: The shell is a snail shaped body welded from ordinary steel plates. The casing of a single suction fan is made in three different forms: the casing of No. 8-12 is made into a whole structure and cannot be disassembled. The shell of No. 14-16 is made into two open types. The shell of No. 18-28 is made into a three open type. Thickened the induced draft fan and volute plate appropriately to prevent wear and tear;

(3) Air inlet: The convergent and streamlined air inlet is made into a whole structure and fixed to the inlet side of the fan with bolts;

(4) Transmission part: The main shaft of the transmission part is made of high-quality steel, and this fan adopts rolling bearings. There are two forms of bearing housings: for № 8~16, integral cylindrical bearing housings are used; Two independent pillow type bearing housings are used for No. 18-28. The bearing box is equipped with a thermometer and an oil level indicator (only for the induced draft fan). The lubricating oil used is No. 30 mechanical oil, and the oil level is implemented according to the oil level mark. When using dry oil for the integral cylindrical bearing box of No. 8-16, an oil baffle should be added on the ball side of the bearing box, and the mutual communication of its fixing groove should be made. The induced draft fan is equipped with a water cooling device, therefore, a water supply pipe must be installed. The water consumption varies with different temperatures, generally considered at 0.5-1m3/h;

(5) Regulating door: a device used to regulate the flow rate of a fan, installed axially in front of the air inlet. The adjustment range is from 0 ° (fully open) to 90 ° (fully closed). Adjust the position of the door handle, looking from the direction of the air inlet on the right side, and push the right whirlwind handle from bottom to top in the direction from fully closed to fully open; The handle of the left cyclone machine is pulled from top to bottom in the direction from fully closed to fully open. In order to ensure the normal operation of all parts of the regulating door, proper lubrication is necessary. The regulating door of the ventilation fan is lubricated with calcium sodium based grease. For induced draft fans, due to the high gas temperature, molybdenum disulfide high-temperature (260 ° C) lubricating grease is used to ensure lubrication during high-temperature operation. For fans above No.16, dry oil should be added at the screw plug.