TK-1 Bimetallic Traps is operated by metal strips made of alloys with different coefficients of expansion that are bonded together.At start-up, the trap is cold and the bimetallic element is relaxed. The valve is wide open. When steam enters the trap, it surrounds and heats the strips, which begin to expand at different rates. The element pulls directly on the valve stem, closing the valve against the pressure differential. As heat radiates from the trap, the strips begin to cool. When the element has cooled sufficiently, it relaxes and opens the valve.TK-1 Bimetallic Traps, specially manifactured for SUPER HEATED STEAM applications. Appropriate isolation valves must be installed to ensure that maintenance and drainage are safe