Method and apparatus for fail-safe control of at least one electro-mechanical or electro-hydraulic component

Abstract

A fault management apparatus and method are described for a system that includes at least one electro-mechanical or electro-hydraulic component, such as a system valve or main discharge pump in a process plant or water transmission line. An actuator is electrically coupled to the component for application of control signals to selectively actuate or de-actuate the component. A standby power supply, in the form of a uninterruptible power supply (UPS) stores sufficient electrical energy to energize the valve and/or the discharge pump to change the states thereof from one operational state to another. The UPS has sufficient electrical capacity to close a system valve to its fail-safe condition. The actuator can be actuated in a number of different ways, including sensing of failure of main power, manual activation or sensing of some emergency condition. Logic circuit, which may be in the form of relay or other logic, and preferably a programmable logic circuit (PLC) is used and programmed to sense the external conditions which require shutdown of the system, in which case the energy stored in the standby power supply is applied to the actuator and the component. The PLC is advantageously programmed to shutdown the system, when necessary, in accordance with a timed sequence, checking or monitoring a system at each step of the sequence as to the continued existence of the condition which required shutdown. Similarly, when the system is automatically returned on line, the PLC is advantageously programmed to check the system along each step of the sequence to insure that all of the conditions are acceptable for return of the system to the on-line condition.

Dependencies are inferred from the claim text.