초록 ▼

A controller for controlling the operation of a motor operated valve combination, including a valve yoke, a valve stem, a valve disc, a valve seat and a motor operator having a motor and drive means interconnecting the motor to the valve stem for movement of the valve stem in a first direction to mo

A controller for controlling the operation of a motor operated valve combination, including a valve yoke, a valve stem, a valve disc, a valve seat and a motor operator having a motor and drive means interconnecting the motor to the valve stem for movement of the valve stem in a first direction to move the valve disc into engagement with the valve seat for closing the valve. The controller comprises a sensor for sensing forces experienced by the valve stem during valve closing and for generating related electrical signals. A first detector is employed for receiving the electrical signals from the sensor, for determining when the rate of change in the valve stem forces exceed a first predetermined limit and for generating an electrical signal when the first predetermined limit is exceeded. A second detector receives the electrical signals from the sensor and from the first detector, determines when, after receipt of the signal from the first detector, the forces experienced by the valve stem exceed a second predetermined limit and generates an electrical signal in response thereto. Motor cut-off circuitry receives the electrical signal from the second detector and stops the operation of the motor in response.

대표청구항 ▼

A controller for controlling the operation of the motor of a motor operated valve combination including a valve yoke, a valve stem, a valve disc, a valve seat and a motor operator having a motor and drive means interconnecting the motor to the valve stem for movement of the valve stem in a first dir

A controller for controlling the operation of the motor of a motor operated valve combination including a valve yoke, a valve stem, a valve disc, a valve seat and a motor operator having a motor and drive means interconnecting the motor to the valve stem for movement of the valve stem in a first direction to move the valve disc toward and into engagement with the valve seat for closing the valve, the controller comprising: sensor means for sensing a parameter indicative of the forces experienced by the valve stem during valve closing and for generating related electrical signals; first detector means for receiving the electrical signals from the sensor means, for determining when the time rate of change in the valve stem force parameter during valve closing exceeds a first predetermined limit indicating that the valve disc has begun wedging into the valve seat and for generating an electrical signal when the first predetermined limit is exceeded; second detector means for receiving the electrical signals from the sensor means and from the first detector means for determining when, after receipt of an electrical signal from the first detector means, the parameter change exceeds a second predetermined limit indicating that the wedging force of the valve disc within the valve seat has been sufficient to prevent leakage through the valve and for generating an electrical signal in response thereto; and motor cut-off means for receiving the electrical signal from the second detector means and for stopping operation of the motor in response thereto.