| 摘要 |
A freeze prevention device for water systems includes a relief valve and an actuator having an elongated chamber which contains water and segments that sequentially sense the incremental expansion caused by ice formation therebetween. The segments are axially aligned within the chamber. The segments may be balls, truncated pyramids, and the like that have a sealing portion and an axial portion with a foot which is adapted to engage an adjusting screw or a wear compensating spring at the bottom of the chamber or the top of the adjacent segment. An actuation linkage transmits linear meovement of one or more segments to a poppet in a valve seat, thereby opening a valve port connecting water, from a water supply system or a tank, to a discharge port, whereby water may be bled from the water system to prevent freezing thereof, or steam from a steam system for admission to tracer lines.
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