摘要 |
An alarm system to monitor pressure in tubes or containers that normally maintain (a) a constant pressure, i.e., a fixed pressure or a pressure of some steady or unchanging magnitude, (b) a periodic pressure, i.e., a pressure which oscillates with a regular interval a recognizable period or a pressure, the magnitude of which varies from some positive value to a value close to or less than zero and then returns to its original positive value in some regular interval of time, (c) or a fluctuating pressure, i.e., a pressure similar to a periodic pressure but differing by not having any fixed period of time for an oscillation; a pressure which shifts from positive to negative uncertainly, is described. This alarm system sets an audible or other signal should pressure in a monitored line fall for a longer than acceptable period.
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