Agitator drives of glass lined agitator vessels must meet the requirements of DIN 28161 with regard to the concentricity of the agitator shaft. This defines the permissible concentricity deviation of the stirrer shaft directly above the mechanical seal as a function of the shaft diameter. For stirrer shafts with a nominal diameter of up to 60 mm, the permissible value is 0.08 mm, above that up to a shaft diameter of 140 mm it is 0.1 mm.

It is very important to observe the tolerance specifications, because the concentricity deviation has a decisive influence on the smooth running of the agitator and the service life of the shaft seal (mechanical seal or shaft lip seal).

The video shows the test run of a CE type agitator vessel with a nominal volume of 10,000 l. A classic glass-lined impeller is used as agitating element.

The concentricity deviation of THALETEC agitators is usually well below the values specified by DIN. This is also the case here. The measured concentricity deviation of this agitator is only 0.03 mm with a shaft diameter of 125 mm. This means that the real concentricity deviation is only 30% of the maximum permissible deviation - a very good value.

With THALETEC agitators you can ensure that you achieve the maximum service life of your mechanical seals and shaft lip seals.