摘要 |
A water or other fluid containing system is protected by a thermostatically controlled drain valve having input, output, drain and control ports. A slideable barrier within the valve selectively directs the flow within the valve between the ports. A small coupling orifice through the barrier and a particularly designed closure for the orifice are provided. A thermosensitive mechanism delivers pressure to the control port to open this closure when ambient temperature drops below a predetermined level. Equal static pressures developed by flow through the orifice in turn develop unequal forces on opposite sides of the barrier, to shift the barrier, redirecting the flow within the valve.
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