Abstract: A valve control system comprises a programmable electronic controller. The programmable electronic controller is configured to provide an emergency actuation signal to a motor upon receiving an emergency close signal. The programmable electronic controller is configured to provide a test actuation signal to the motor upon receiving a test close signal. The valve control system further comprises a gas detection input configured to receive a gas detection signal. Receipt of the gas detection signal at least partially meeting a first criterion causes the emergency close signal to be supplied to the controller. The valve control system further comprises a user interface configured to provide the controller with the test close signal in response to a user input. The valve control system further comprises a low battery input configured to receive a low battery signal. Receipt of the low battery signal causes the emergency close signal to be supplied to the controller.

Abstract: A valve structure is provided having a housing with an open top valve chamber and inlet and outlet passages on opposite sides of the valve chamber forming a through passage with the valve chamber through said housing, a generally spherical radius valve seat on each passage at the valve chamber, a bonnet removably covering said valve chamber, a stem extending through said bonnet generally axially of the valve chamber, a pair of generally spherical radius closure discs in the valve chamber sealingly adapted to engage the valve seats, a disc carrier for each disc in the valve chamber, each disc carrier having a through passage in a plane transverse to the plane of the disc providing full flow therethrough from the inlet to the outlet passage when the valve is in opening position, an eccentric means provided on the stem and engaging each disc carrier for selectively moving the discs into and out of engagement with the valve seats and a guide between the bonnet and at least one of said disc carriers guiding the di