Roots blower is a type of displacement fan. There are two impellers that rotate relatively in the space sealed by the casing and wallboard. Since each impeller is involute or the envelope of the epicycloid, the three blades of each impeller are identical, and the two impellers are also identical, which greatly reduces the processing difficulty.
The impeller is processed with numerical control equipment to ensure that no matter where the two impellers rotate, a certain minimum clearance can be maintained when the middle distance between the two impellers is constant, so as to ensure that the gas leakage is within the allowable range. The two impellers rotate in opposite directions. Because the clearance between impellers and impellers, between impellers and casings, and between impellers and wallboards is very small, a vacuum state is formed at the air inlet. The air enters the air inlet chamber under the action of atmospheric pressure. Then, two of the blades of each impeller form a sealed chamber with wallboards and casings, The sealing chamber formed by two blades is constantly taken to the exhaust chamber. Because the impellers in the exhaust chamber are meshed with each other, the air between the two blades is squeezed out. In this way, the air is continuously transmitted from the air inlet to the air outlet, which is the whole working process of Roots blower.
The gear pair of Roots blower is generally supported by 45 steel. The gear pair of the two blade roots blower is not only a pair of transmission gears, but also a pair of synchronous gears. Only when the two gears have the same angle of rotation, can the two impellers of the blower operate normally. Otherwise, the two impellers will collide and damage the normal operation of the blower, or even cause equipment accidents.
Most gear pairs on driven shaft of Roots blower are made of gear ring and gear hub assembly. The clearance between impellers can be achieved by adjusting the driven gear ring. During adjustment, it is only necessary to remove the locating pin and rotate the screw, that is, rotate the moving gear ring to adjust the impeller clearance. After the clearance is adjusted, tighten the fastening screw, drill and ream the locating pin hole again, and install a new locating pin.
The gear backlash shall not be greater than or equal to the tooth clearance of two blade gears during design. Practice has proved that when the gear backlash is more than two-thirds of the impeller clearance, the two impellers will collide during operation. In this case, the two cogged gears need to be updated or readjusted.
The gear and shaft adopt high precision transition fit, and the key used to fix the gear adopts special tolerance fit to prevent the gear key from loosening, so that the gear can be tightly fixed on the shaft, so as to avoid increasing the gear side clearance once the gear is loose, so that the two impellers will collide.
The wheel slide of Roots blower with low flow, low pressure and low speed generally adopts closed oil tank, and an oil slinger splash lubrication gear is installed on the main shaft end. For the gear of Roots blower with large flow, high pressure and high speed, the oil pump is used for circulating lubrication.
I believe that after reading the above, you should also know how to correctly adjust the gear of Roots blower. I hope it will help you.
Text term label: Roots blower
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