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Abnormal Knocking Sound in Agitator vessel and agitator shaft heavy wobbling .

From: dc_chauhan62@yahoo.co.in
Remote Name: 81.93.34.177

Comments

Trial of equipment was conducted and observations are as mentioned below. Capacity:107 m3 Motor RPM : 1475 Motor kw:45 Frequency: 50 Hz. Gear box out put RPM :48 Agitator shaft length:8.624 meter Agitator shaft Diameter:120 mm Shaft run out:2.5 mm Seady bearing clearance:1.05mm Agitator Trial Taken with: Water at normal atmospheric temperature and pressure. No pump was in line during trial which indicates knocking sound is from vessel only. Water Level Load in amps Vibration in mm/sec Observation on abnormal sound in vessel Motor Drive shaft Gear box out put shaft Mounting Flange Above Steady Bearing and below bottom impeller 20 0.2 0.3 0.1 No abnormal knocking sound and observed smooth rotation from manhole. Also no shaft wobbling. 20% 45~50 1.5 1.6 0.4 From manhole observed slight knocking sound and shaft wobbling of about 12~15 mm. 33% 48 2 2.1 0.3~1.4 From man hole observed increased in Intensity of knocking sound and shaft wobbling increased compared to at 20 % water level.( Shaft wobbling 15~25 mm ) 50% 45~51 4.9 3.9 0.9 Intensity of knocking sound increased. ( Checking of shaft wobbling not possible due to manhole closed condition). This type of phenomenon observed in other agitators also and plant is in commissioning stage.We carried out checking for the looseness in agitator assembly and found every thing normal.Again all checks carried out as per the vendor specification.We have fear that shaft may got broken after certain period of running or may damage the steady bearing of carbon material. Here in this case I would like to know 1).Is it advisable to put agitator in the sevice? 2).Is there any possibility of failure? 3).Which parts will get damaged if put in to the service? 4).Is there any way by means we can monitor the condition of steady bearing bush? I seek your guidence / opinion in this matter at the earliest. With warm Regards, Dinesh Chauhan

Last changed: October 16, 2007