The fan plant with axial two-stage counter-rotating fans VDK consists of the first stage main fan device, the second stage main fan device (including housing, bed, electric motor, impellers, brake unit), volute chamber pipe, volute chamber tower, sound-absorbing assembly to switch shaft covers yoke with winch, and starting and controlling equipment.
First and second stage fans include: split housing (upper, lower), protective sheath for electric motor and braking device, electric motor with impeller, and braking device.
First and second stage fans are installed coaxially to the calculated technical gap between the end planes of the impellers, which are rotated in the opposite direction. This design eliminates the use of guiding devices of conventional axial fans. In this regard, the VDK fan has a higher efficiency factor (above 80%).
A special three-phase asynchronous electric motor of YBF type with the explosion protection category dl, protection category IP44, insulation class F, output box protection category IP54, and temperature exceeding class B is used to drive the VDK fan impellers.
The electric motor is equipped with a bearing and stator temperature measuring device and a heating device to facilitate starting in winter.
Each main electric motor and braking device is mounted inside an enclosed streamlined shell (envelope) located inside the fan housing. This eliminates the contact of electric motors with mine air and provides an additional explosion protection. The main motors are cooled by atmospheric air through special supply and exhaust ducts.
The electric motor design allows for partial replenishment or replacement of grease in the rotor bearing assemblies by means of oil-filling pipelines led from the bearing assemblies outside the fan housing.
To reduce noise, the housings of the first and second stage fans are equipped with sound-absorbing baffles mounted on the side surfaces. The average noise level at a distance of 1 meter does not exceed 85 dB.
A flow stabilizer device is installed in the ventilating pipe to ensure fan performance and surge-free fan operation.
Two wheels rotating in opposite directions function both as impellers and directing air flow from one wheel to the other, which, compared to conventional axial fans, avoids energy loss on the middle and rear guiding devices and between the electric motor and the impeller.
Wide-range regulation of the VDK fan operation mode is carried out by changing the number of operating electric motors (simultaneous operation of one of the two is possible), the angle of wheel blades installation, and by changing the wheels and type of electric motors.
There are 5 holes on the wheel drum to indicate the blade angle, which correspond to angles: 25°, 30°, 35°, 40°, 45°, by which the blade angles can be changed when the amount of mine air needs to be changed.