• Halma India

Mechanical Interlocks with Process Safety Sensors

Smith Flow Control offers SmartTrap+, which combines Mechanical Interlocks with Process Safety Sensors. In the process industry, mechanical interlocks guarantee strict adherence to procedures and help avoid human error. They are particularly useful for highly dangerous operations such as pigging and valve changeover procedures. While interlocks ensure extremely high safety levels, they usually function as stand-alone safety systems. New digital technologies are now emerging that enable traditional interlocking to be combined with digital process control and instrumentation systems. Smith Flow Control is the first company to combine these mutually beneficial technologies in the development of the SmartTrap+, which incorporates signals from sensors into the interlocking sequence. During a pigging operation certain safety conditions need to be met: the vessel pressure should be at a safe level and all dangerous gases and residue must be removed before opening the pig door. Mechanical interlocking guarantees that all required valve operations are performed, but cannot guarantee the outcomes of these operations. By incorporating signals from other field devices like pressure or H2S/CO2 sensors into the interlocking sequence, the SmartTrap+ ensures interlock keys can only be released if particular process conditions have been met. So, for example, this could mean that the key for opening the vessel closure door will only be released when the pressure inside the vessel is acceptable and no dangerous gases or residue are detected.