Boiler oil supply system from underground tank

摘要

The system (1) recirculates oil in a thermally insulated (5) coaxial pipe (2). The annular outer pipe carries oil from the tank to the boiler, and the inner pipe (3) serves as the return line (11) from the boiler to the tank. The coaxial pipe is made of copper or stainless steel. The outer pipe has an expandable bellows (4) of the same material as the pipe to compensate for differential thermal expansion. Brass T-connectors (6,7) enable the oil supply to enter and leave at right angles to the axis of the coaxial pipe. A non-return valve (12) is located in the oil return line in the T-connector at the burner end of the line.