Boiler glossary

Boiler glossary T


TACK WELDING -- Making short, provisional welds along a joint to hold it in position and prevent distortion during subsequent continuous welding.
TANK TOP -- Upper plating of a double bottom.
TEU-- Maritime abbreviation for "twenty-foot equivalent unit" which refers to a container that is 20 feet in length (6.1 meter), 8 feet wide (2.4 meter) and a little over 8 feet high. See FEU
THERMOCOUPLE -- A temperature measuring sensor. If two wires of different metals are joined at their ends to form a loop, and a temperature difference between the two junctions unbalances the contact potentials, a current will flow round the loop. The temperature of one junction is kept constant and the temperature of the other is indicated by measuring the current.
THERMOSTAT -- An instrument that responds to changes in temperature and directly or indirectly controls the temperature.
THERMOSTATIC STEAM TRAP -- A steam trap that opens by a drop in temperature such as when cold condensate or air reaches it and closes it when steam reaches it.
THORNYCROFT BOILER -- A water tube boiler with downcomers.
THRUST BEARING or THRUST BLOCK -- A shaft bearing designed to take an axial load. It consists of a plain bearing pads, a Michell bearing, or a ball bearing provided with lateral races.
TIE-ROD -- A structural member subject to tensile tension only.
TREATED WATER -- Water that has been chemically treated to make it suitable as boiler feed water.
TRIPLE EXPANSION ENGINE -- A steam engine in which the steam expands successively in three cylinders of increasing size, all working on the same crankshaft.
TUBE EXPANDER -- A tool used to expand the tubes into the tube sheets, and also to bead over the ends.
TURN DOWN RATIO -- The ratio of a burner's maximum output to its minimum output.
TUYERE -- The opening through which air is forced into a blast furnace to facilitate combustion.