Roots blower, working air chamber and bearing seat are sealed with carbon ring. The rear end bearing is a thrust bearing bearing the radial force and axial force of the rotor. The front end bearing is a support bearing that bears the radial force of the rotor. The front end cover and shaft are sealed with skeleton oil seal. There is a pair of helical gears at the tail end as synchronous gears. The power transmission mode is belt pulley transmission. The radial positioning of Roots blower ensures that the axial positioning needs to be adjusted through the production of parts, and the adjustment of the rotor axial positioning is crucial to the operation of the whole blower.
The main function of the axial positioning of Roots blower is that when the blower is running, the shaft system will produce linear expansion and body expansion due to the rotor heating. The volume expansion reserve is ensured by radial processing, and the linear expansion reserve is determined by axial positioning. If the axial reserve is too large, the fan efficiency will become low: if the axial reserve is too small, the fan casing and bearing will be damaged due to heating.
Generally speaking, inaccurate axial clearance will cause the following faults: in order to better understand the role of the axial positioning of Roots blower, the following makes a systematic analysis of the problems caused by incorrect positioning:
There are two main reasons for bearing end face wear. One is that foreign matters enter the end face of rotor and bearing seat, which is too rare to be analyzed here. The other is when the rotor expands online due to insufficient axial clearance
Contact wear with bearing end face. We know that the molecules of any substance are doing irregular thermal movement, so the molecules have speed and kinetic energy. Microscopically, the pressure of gas is the impact of a large number of molecules on the container wall, and the temperature is the measurement of the average kinetic energy of the thermal movement of a large number of molecules. The higher the temperature is, the greater the average kinetic energy of the molecular thermal movement is, and the greater the molecular speed is. We know that the greater the speed is, the more violent the impact is, that is, the greater the pressure of the gas is. When the fan
When pressure is generated, on the contrary, gas will generate temperature. The temperature causes the rotor to stretch, and if the clearance is not enough, it will cause friction between the rotor and the casing. Too large axial clearance will reduce fan efficiency. As Roots blower is a positive displacement fan, its wind pressure has something to do with the system, but has little to do with others. That is to say, it has a certain relationship with the characteristics of the outlet pipe. The flow rate has a great relationship with the fan speed. However, if the axial clearance is adjusted too large, a gas channel will be formed at the impeller end face and the bearing seat end face. The gas channel will make the air being boosted return to the suction port of the fan through it, making the fan continuously do quantitative reactive work, reducing the fan air volume and efficiency.
Text label: Roots blower
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