| 摘要 |
<p>The system includes a fan (2) linking the space to a pipe (3), via a further pipe (4), in order to maintain a pressure in the space slightly greater or slightly less than atmospheric pressure. A differential manometer (5) is linked to the space via a pipe (6), and also linked to the outside via a second pipe (7). The manometer produces an alarm signal if the pressure inside changes by more than a certain threshold relative to the outside pressure. When used for dwellings or shops, the gas may simply be air whereas nitrogen is pref. used for protecting safes. The differential pressure gauge arrangement is intended to prevent false alarms.</p> |
