Automatic non-invasive blood-pressure meter - Has pump connected to flexible bag around arm via stopcock controlled by comparator circuit

A flexible, non-elastic bag (1) filled with liq. is attached to the inside of a rigid, adjustable circular clip (2) (or non-elastic sleeve) that wraps around the patient's upper arm. The liq. is pumped (3) from a reservoir (4) via a stop valve (7) to the bag. A display (5,6) is connected to the bag and shows the pressure in it. This pressure is raised to lie between the diastolic and systolic pressures. The highest and lowest pressures of the liq. are shown immediately (no inertia). Whilst the pressure is building up, the peaks of the blood pulses are measured. The pressure increase is stopped when the difference between two consecutive peaks is zero or lies below a given limit. The display contains a transducer converting pressure into an electrical signal. The signal is connected via a voltage holding circuit to a memory. A comparator compares the memory's input and output signals. The stop cock (7) is automatically closed, disconnecting the pump from the bag, when the comparator's difference is zero.