What are the treatment methods for vibration, heating and abnormal noise of Roots blower?

Roots blower is mainly composed of casing, wallboard, impeller, inlet and outlet muffler, etc. The casing is mainly used to support the wallboard, impeller, muffler and fixation. The wallboard is mainly used to connect the casing and the impeller, support the rotation of the impeller, and play the role of end face sealing. The impeller is the rotating part of Roots blower, which is divided into two leaves and three leaves. Now, the three leaf blower has gradually replaced the two leaf Roots blower because of its advantages such as less pulsation, less noise and smooth operation than the two leaf blower. Muffler is used to reduce the noise generated by the inlet and outlet airflow pulsation of Roots blower.

Treatment of vibration, heating and abnormal sound of Roots blower:

1. Solution to the center distance deviation of fan gear pair and the center distance deviation of gearbox shaft hole

Although the existence of this error has been verified through measurement and theoretical calculation, the matching deviation between the gear center distance of Roots blower, the parallelism error of gear axis, the center distance deviation of gearbox shaft hole and the parallelism error of gearbox shaft hole have been determined in the equipment manufacturing, so the error cannot be adjusted in the maintenance. The only way to solve these errors is to replace the fan gear and impeller shaft in pairs, reduce or eliminate the gear backlash, and eliminate such faults.

2. Methods for fan vibration caused by improper adjustment of bearing axial clearance and wear of bearing pedestal

First, check the wear of bearing rollers and ballistics, and then measure the clearance of rolling bearings to see if there is poor axial positioning of bearings. Usually, adjust the axial clearance by adding or subtracting lead pads on the bearing end caps. If they are all within the standard value range, take down the bearing to check whether the bearing has run out of the outer ring. If there is wear trace in the bearing chamber, use epoxy resin, a certain amount of phthalic acid and ethylene diamine for bonding and fixation, which can eliminate such failures.

3. The method of adjusting the clearance between the impeller, wallboard and casing by adjusting the position of the driven gear locating pin

The driven gear is composed of a gear ring and a gear hub. The locating pin on the driven gear is designed to adjust the clearance. When overhauling Roots blower, do not fix the locating pin between the gear ring of driven gear and the gear hub before installing the gear pair. Install the driven gear into the blower first.

At this time, the driving gear and driven gear are manually turned through the coupling to adjust the clearance between the gear pair and the impeller. After the clearance is adjusted, fasten the lock bolt between the gear ring of the driven gear and the gear hub, remove it from the equipment as a whole, and re select the location of the positioning hole. The positioning hole obtained at this time is the current accurate positioning size of the fan. After installation, tilt the two impellers by 45 °, align the driven gear with the driving gear and press it onto the shaft, and then install the gear retainer ring, gear washer and lock nut in turn. Turn the gear. If it cannot rotate, rotate the impeller and adjust the position of the gear until it rotates flexibly without scratching or dead point.

At this time, tighten the lock nut, measure the gap between the two impellers with a feeler gauge, and control the gap between 30-60 wires. Then, fasten the gear ring and gear hub of the driven gear with the lock nut, remove them, and drill on the lathe. In this way, the tooth side clearance of the gear pair and the clearance between the impellers can be accurately determined, ensuring that the clearance between the impeller and the casing and the wallboard meets the design standards.