MIURA's EX Gas/Oil Series High Pressure Steam Boiler features a "low water content watertube" design. The EX Series is a once-through, forced circulation steam boiler producing steam in just five minutes, while maintaining an 85% fule-to-steam efficiency. The unit's design consists of rows of vertical tubes sandwiched between two annular headers. Both headers are encased in a castable refractory with only the tubes exposed to flame and/or combustion gases. The upper header is attached to the lower header only by the tubes; as the tubes expand and contract, the headers float up and down accordingly. This 'floating header' concept, aided by forced flow, greatly reduces stress and allows for the use of cold feedwater without the fear of significant thermal shock. MIURA.