Patent ID: 11965607
Assignee: CKD CORPORATION
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 1:
2. The butterfly valve according to claim 1, wherein
the abnormal vibration detection program is configured to calculate first number of pulse counts for calculation of the actual variation amount and second number of pulse counts for calculation of the accumulated variation amount based on a pulse output by the encoder,
the first number of pulse counts is calculated by counting up when the butterfly valve element rotates in the opening direction or closing direction or by counting down when the butterfly valve element rotates in an opposite direction to the direction for which the first number of pulse counts is counted up,
the actual variation amount is a difference between the first number of pulse counts at the starting time point and the first number of pulse counts at the ending time point,
the second number of pulse counts is calculated by counting up irrespective of the direction of rotation of the butterfly valve element, and
the accumulated variation amount is a difference between the second number of pulse counts at the starting time point and the second number of pulse counts at the ending time point.