Abnormal Condition Detection On Shut Down Valve And Blow Down Valve

A system for detecting abnormal operating conditions in a shutdown valve, the system comprising:

• an inlet pipe and an outlet pipe;
• a flow-controlling element located between the inlet and outlet pipes;
• a stem connected to the flow-controlling element and driven by an actuator arrangement;
• a first detector system for detecting stiction of the flow-controlling element, the first detector system including a first predictor connected to the stem for detecting the position of the flow-controlling element transferred through the stem with at least one sensor of the group consisting of a motion sensor, an acceleration sensor, or a shock sensor;
• and
• a second detector system for detecting a leak in the flow-controlling element, the second detector system including a second predictor for detecting vibrations in the flow-controlling element.

A method for automatic, unattended online verification of the safety performance of a shutdown valve in a live process while the shutdown valve is activated by a remote-control signal to perform a safeguarding action, the shutdown valve comprising an inlet pipe and an outlet pipe, a flow controlling element with a stem connected to and driven by an actuator, a first detector system fixed to the stem including a first predictor with a first microcontroller, a motion sensor, an accelerometer sensor, and a first shock sensor, the first detector system (i) detecting stiction, friction, position, and vibrations of the flow controlling element through the stem, (ii) detecting stem torque induced in the stem by use of an external strain gauge sensor, or (iii) detecting actuator pressure in the actuator by use of an external actuator pressure sensor,

• wherein the first predictor is adapted to transmit the position of the flow controlling element to a second predictor having a second microcontroller, and at least one sensor in the group consisting of (i) a second shock sensor detecting leakage flow in the flow controlling element, (ii) a temperature sensor detecting temperature of fluid flow, (iii) an external pressure sensor detecting fluid pressure in the outlet pipe, and (iv) a strain gauge sensor clamped to the outlet pipe for detecting fluid pressure in the outlet pipe;
• and wherein the method includes:
• a) computing dynamic movement data and stiction data from the sensors of the first detector system;
• b) comparing the computed stiction data with predefined acceptable stiction data, and if the computed stiction data is out of an acceptable range, storing stiction deviation data and generating a stiction alarm;
• and
• c) comparing dynamic movement data with predefined acceptable movement data, and if computed dynamic movement data is out of an acceptable range, storing movement deviation data and generating a movement alarm.