Visual Inspection
Direct Observation
After the mixer is shut down and the power is cut off to ensure safety, open the inspection door or protective cover of the mixer. Observe the mixing blades directly with the naked eye. Pay particular attention to the edges, bends, and the connection parts with the mixing shaft. Under normal circumstances, the blades should maintain their original designed shape. If there are obvious bends, twists, or wrinkles on the blades, it indicates that the blades have deformed.
Comparison Reference
For mixers with multiple mixing blades, compare the suspected deformed blade with other blades that appear normal. If there are significant differences in the shape of a certain blade compared with others, such as different degrees of bending or inconsistent inclination of the blade plane, it is likely that the blade has deformed.
Inspection with Measuring Tools
Measurement with a Straightedge
For large - area flat blades, use a straightedge for measurement. Place the straightedge against the surface of the blade and observe if there are gaps between the straightedge and the blade. If there are gaps, it means the blade surface is uneven, and local deformation may have occurred. Measure the maximum width of the gap and record the data for subsequent tracking of the development of the deformation.
Measurement with an Angle Gauge
For mixing blades with a specific designed angle, such as blades at a certain angle to the mixing shaft or blades with a bent angle, use an angle gauge to measure the actual angle. Fit the angle gauge to the corresponding part of the blade, read the measured angle, and compare it with the standard angle specified in the mixer's design specifications. If the deviation of the actual angle from the standard angle exceeds the allowable range, it indicates that the blade has undergone angular deformation.
Measurement with a Plumb Bob and a Measuring Tape
For longer mixing blades, a plumb bob and a measuring tape can be used to check their straightness. With the line of the plumb bob perpendicular to the ground, bring the line close to the edge of the blade. Use the measuring tape to measure the distance between the edge of the blade and the line at different positions. If the distance varies significantly, it indicates that the blade is bent along its length.
Indirect Inspection during Operation
Observation of Material Mixing Effect
During the normal operation of the mixer, pay attention to the mixing of materials. If the materials are not mixed evenly, such as local material accumulation or insufficient mixing in some areas, it may be due to the deformation of the mixing blades, which prevents them from effectively driving and dispersing the materials. For example, when mixing concrete, if some cement is not completely mixed with the aggregates, it may be that the corresponding mixing blade is deformed, affecting the mixing effect.
Monitoring of Operating Sound
When the mixer is running, listen carefully for any abnormal sounds. During rotation, the deformed mixing blades may rub or collide with other internal components of the mixer (such as the lining plate), producing sharp friction sounds or irregular impact sounds. Once such abnormal sounds are heard, immediately stop the machine to check if the blades are deformed.