Dry quenching circulation fan rotating stall simple fault diagnosis

Dry quenching circulation fan rotating stall simple fault diagnosis points - 2019 02 - 21 peng beg flourishing ( Gelatinization run dry quenching technology exchange learning platform) Rotating stall is due to the small volume flow gas medium, in centrifugal ( And the axial flow) Fan impeller and diffuser flow occurring in the airflow pulsation phenomenon. Dry quenching circulation fan for centrifugal fan, its working state is influenced by many factors, when the volume flow rate lower, the entrance of the impeller reduced the absolute velocity of the gas, gas to a relative velocity at the back of the impeller channel will be inconsistent with the designed working condition and produce deviation and rushed to blade working face, near the original face of the air flow at the exit out of the area because of a lack of mainstream to promote and expand, form vortex mass obstruction in the flow passage between the blades. Out of regiment to flow into the leaf gas is blocked, can only change direction into the adjacent leaf. Fang Yedao before flowing into the direction of rotation of the airflow to blade working face, the original out of the area; Flow after Fang Yedao airflow into the working face, the face of detachment area to expand into a mass of obstruction in the road. So, from the mass of the mobile is produced in the impeller. From the group's direction is always contrary to the direction of rotation of the impeller, the but again together with the impeller rotation, thus will look from the absolute coordinate system, its rotation speed is lower than the impeller speed, so called rotating stall, also known as spin out. Phenomena of rotating stall is actually a surge of precursors. At the heart of the rotating stall is airflow pulsation, and bearing vibration is not the cause of flow pulsation, that is to say, with and without air flow pulsation phenomenon is the key difference between rotating stall and bearing failure. Rotating stall has the following characteristics: (1) abnormal voice, like the roar of the sound, listen to the fan on the import and export pipeline to have intermittent flow pulsation. (2) inlet outlet pressure and flow down, at the same time, judge whether the volatility of the vibration value and flow pulsation ( Fluctuation of the pressure, flow rate, Synchronization; (3) current fluctuation; (4) bearing vibration is not obvious, the fan shell vibration is more intense; 5. If there is one vibration spectrum analyzer to measure, usually. The frequency range, the impeller is stalled for ( 0. 5 to 0. 8) Frequency doubling, diffuser is stalled for ( 0. 1 to 0. 25) Frequency doubling. The fundamental reasons of rotating stall is fan inlet volumetric flow rate is low, causing low flow the most important reason is that the impeller flow channel, air flow blocked, causing the leaves into the air volume is not enough, vortices leads to the formation of a circulation gas, causing the fan vibration, in some cases there will be a bearing vibration phenomenon is not obvious but the fan shell, such as the phenomenon of violent vibration, even will be torn. Therefore, in the operation of the dry quenching cycle fan in a different sound, need to inspect 2 dc dust removal effect and material level, at the same time, combining with the dust concentration in judgment, a slight rotating stall will not cause too much damage to the machine, but to pay attention to the anchor bolt connection parts and bearing shell, prevent tearing shell connection and anchor bolt looseness.