| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an electric actuator for a valve including a biting detection function in which detection of biting of foreign materials can be carried out accurately and within a short period of time without performing any erroneous detection of a temporary increase in torque of a motor irrespective of any operating direction of the valve and when the biting of foreign materials is detected, a foreign material discharging operation is carried out automatically.SOLUTION: This invention relates to an electric actuator for a valve including a biting detection function characterized in that there are provided some divided segments which are divided in a specified time interval ranging from a near full-closed state to a full-opened state when a valve is opened or closed, a valve operating amount (a valve rotating angle or the like) at a divided segment for every divided segment is measured, this measured operating amount is compared with a threshold belonging to the divided segment where the valve operating amount of an operating amount estimated value (threshold) set in response to an opening degree characteristic (a valve angle and the like) in sequence, and an abnormal state such as biting of foreign materials is detected for every divided segment in reference to the result of comparison.</p> |
