| 摘要 |
A dual fuel boiler has fuel delivery apparatus coupled to its burner section through a pressure regulator and operative to deliver to the burner section, from sources thereof, a selectively variable one of (1) a first fuel at a pressure greater than the pressure regulation setting of the pressure regulator, and (2) a second fuel at a pressure less than the pressure regulation setting, the second fuel having a Wobbe index greater that that of the first fuel. The first fuel is flowed to the burner section via a branch supply line in which first and second electromechanical two position, two-way, two position valves are installed in series in opposite normal flow orientations to thereby prevent backflow of the second fuel into the source of the first fuel.
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