When the Machine is running, torsional vibration due to varying cyclic torques built up. There will be a natural frequency for the whole system and if the frequency of the vibration is equal to multiple of the natural frequency, a condition of resonance is set up. Resonance will cause unacceptable torsional vibration and stresses to be induced.
Engine speeds at which this can occur is termed critical speeds.
Pasteurization requires that the milk is in custody for a specified time. The appropriate length for the holding tube can be calculated by the flow rate (Q) of milk and the diameter (D) of the holding tube using the formula: Length of holding tube, L = Q x holding time/A x η A = Area = pi/4 x sqr D Where an efficiency factor, η, of 0.85 is used in the model.