PURPOSE: To facilitate water extraction from the indoor side and to prevent the apparatus from freezing even when the water extraction is not carried out by providing a drain valve which is closed when the water pressure has a predetermined pressure value and is opened when the water pressure is more than the predetermined pressure value, on the upstream side from a water quantity adjustor.
CONSTITUTION: A drain valve 10 is mounted on the lowermost part of a water passage at the intermediate of a water governor of a water supply port 1. The drain valve 10 has diaphragms 11 the central portion of which are opened, and are mounted with packings 12. The packings 12 and the valve seat 14 are constantly opened by means of a spring 13. When a water pressure is applied onto the drain valve 10, the water pressure is applied to a high pressure chamber 15, and the packings 12 and the valve seat 14 are closed by the diaphragms 11. When the water pressure is eliminated, the packings 12 and the valve seat 14 are opened, and water is drained out of a drainage port 16. In this case, when the pressure of the spring 13 is set to approximately 0.1W0.2kg/cm2, a water feed plug 18 is closed, and a cock 20 is opened, whereby the drain valve 10 is opened. Hence, air is charged through air charge valves, 7 and 8 and water is drained.
KATAYAMA HITOSHI
OOKAWA SEIICHI
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