| 摘要 |
The deflation of the inflatable and deflatable cuff worn by a subject during automatic sphygmomanometric measurement is accomplished in unequal size decrements and principally in larger steps than 7 Torr. Each step after detection of the initial oscillations is determined in the first instance by reference to a look-up table or an equation as a function of prevailing cuff pressure. This Base Step dimension is augmented by a factor proportional to the last oscillation amplitude, the factor being increased after detection of the maximum oscillation amplitude. A valve mechanism with at least two different effective orifice sizes is used for deflation, the smaller size effective orifice being used first, to maintain control over the decrement step rate while holding the time for decrement within a predetermined limit of 8 mSec. per Torr, i.e., maintaining the rate above 125 Torr per second. The valve mechanism can consist of two valves with unequal orifice size, or it can consist of two equal orifice size valves to be used singly for providing the effective smaller orifice, or in parallel to provide the effective larger origice. Alternatively a single variable orifice valve can be used.
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