초록 ▼

A dual mode valve actuator for automatically controlling the operation of a valve comprises a first reversible drive motor and a first planetary drive assembly which operate to move the valve stem axially during a first mode of operation. The actuator further comprises a second drive motor and a sec

A dual mode valve actuator for automatically controlling the operation of a valve comprises a first reversible drive motor and a first planetary drive assembly which operate to move the valve stem axially during a first mode of operation. The actuator further comprises a second drive motor and a second planetary drive assembly which cooperate with the first planetary drive assembly to rotate the valve stem without axial movement during a second mode of operation. A control means is provided to control the operational mode of the actuator.

대표청구항 ▼

A dual mode valve actuator for automatically controlling the operation of a valve having a valve stem, comprising: a first drive motor activated during a first mode of valve actuator operation; a first planetary drive assembly operatively coupled to the first drive motor and to the valve stem; a sec

A dual mode valve actuator for automatically controlling the operation of a valve having a valve stem, comprising: a first drive motor activated during a first mode of valve actuator operation; a first planetary drive assembly operatively coupled to the first drive motor and to the valve stem; a second drive motor activated during second mode of valve actuator operation, and operatively coupled to the first planetary drive assembly; a second planetary drive assembly operatively coupled to the second drive motor and to the valve stem; whereby during the first mode of operation, said valve stem is driven by said first planetary drive assembly to move axially, and during the second mode of operation, the two planetary drive assemblies are driven into rotation to rotate the valve stem without axial movement thereof; the valve actuator further comprising torque sensing means for sensing the torque developed by the valve stem during the first mode of operation, the torque sensing means including control means for causing the actuator to operate in the second mode of operation by deactivating the first motor and activating the second motor when the torque sensed exceeds a predetermined torque limit.