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1. Purpose
G4-68 and Y4-68 centrifugal ventilation and induced draft fans are suitable for ventilation and induced draft matching of steam boilers below 230t/h in thermal power plants. Unless otherwise specified, G4-68 type can also be used for mine ventilation and general ventilation.
The medium conveyed by the ventilation fan is air, and the maximum temperature shall not exceed 80 ℃. The medium conveyed by the induced draft fan is flue gas, and the maximum temperature shall not exceed 250 ℃. Before the induced draft fan, a dust removal device with a dust removal efficiency of not less than 85% must be installed to reduce the dust content of the flue gas entering the fan and improve its service life.
2. Form
(1) The ventilation fan and induced draft fan are both made into single suction units, each with 7 machine numbers ranging from No.8 to No.16.
(2) Each type of fan can be made into two types: right rotation or left rotation. When the fan is viewed from one end of the motor and the impeller rotates clockwise, it is called a right cyclone, represented by "right". When the impeller rotates counterclockwise, it is called a left cyclone, represented by "left".
(3) The outlet position of the fan is represented by the angle of the air outlet of the casing. Both the "right" and "left" fans can produce six angles: 0 °, 45 °, 90 °, 135 °, 180 °, and 225 °.
(4) The transmission mode of the fan is D-type, and the connection between the motor and the fan adopts elastic coupling direct transmission.
(5) The full name of the product is as follows: GY4-68No.8D, right 90 °, where G and Y respectively represent boiler ventilation fan and boiler induced draft fan.
3. Structural characteristics
The fan is mainly composed of an impeller, a casing, an air inlet, a regulating door, and a transmission part.
(1) The impeller is composed of 12 rear inclined wing shaped blades welded between the arc-shaped wheel cover and the flat plate disc. Due to the use of wing shaped blades, the high efficiency, low noise, and high strength of the fan are ensured. The impeller runs smoothly after static and dynamic balance correction. The impeller structure of the ventilation and induced draft fans with the same machine number is the same.
(2) The casing is a snail shaped body welded from ordinary steel plates. The casing of the fan is made into an integral structure. For the induced draft fan, there is a dust cleaning door on the volute plate, and it is appropriately thickened to prevent cigarette ash wear and extend its service life.
(3) The air inlet is a convergent streamlined overall structure, fixed to the inlet side of the casing with bolts.
(4) The regulating door is a device used to adjust the flow rate of the fan. No.8-12.5 consists of 11 petal shaped blades, No.l4-16
Composed of 13 braided blades, all installed axially in front of the air inlet. Due to the use of an external transmission structure, the rotation is flexible and convenient. The adjustment range is from 90 ° (fully closed) to 0 ° (fully open). Adjust the lever position of the door, looking from the direction of the air inlet, on the right side. For the right cyclone machine, pushing the lever from bottom to top is the direction from fully closed to fully open; For the left cyclone machine, pulling the lever from top to bottom is the direction from fully closed to fully open.
In order to ensure the normal operation of various parts of the regulating door, it is necessary to lubricate them well. The regulating door of the ventilation fan is lubricated with calcium sodium based grease. For the induced draft fan, due to the high gas temperature, molybdenum disulfide high-temperature (260 ℃) lubricating grease is used to ensure lubrication during high-temperature operation.
(5) The transmission method of the transmission group is all D-type. Composed of spindle, bearing box, coupling, etc. The spindle is made of high-quality steel. Adopting a rolling bearing water-cooled integrated bearing box. Therefore, it is necessary to install water pipes, and the water consumption varies depending on the ambient temperature, generally considered at 0.5-1m3/h. The bearing box is equipped with a thermometer and an oil level indicator. The lubricating oil adopts the full loss system oil L-AN46, with the requirement of adding oil level markings to the oil gauge.
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