the enclosure being itself a valve, tap, or cock

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Devices, e.g. valves, for venting or aerating enclosures (equalising valves F16K17/00; arrangement or mounting in pipes or pipe systems F16L55/07; venting or aerating as an additional function of steam traps or like apparatus F16T; ventilation of rooms, vehicles, see the appropriate subclass, e.g. F24F) > the enclosure being itself a valve, tap, or cock