GB1460816A - Pressure monitors suitable for lung ventilators - Google Patents

Abstract

1460816 Pressure monitors VERIFLO CORP 27 March 1974 [4 May 1973] 13685/74 Heading A5T [Also in Division G1] A fully pneumatic pressure monitor (14) Fig. 2, (not shown), suitable for a lung ventilator having a pressurised gas supply 11 and an airway 12 for connection to a patient, comprises a pressure regulator 17 connected to said supply, an airway pressure sensor 23, a low-limit pressure detector 24 connected to said sensor, a pneumatic timer supplied with gas through a needle valve 105 and having a valve 121, 122 which opens when gas from valve 105 builds up to a predetermined pressure level to send an actuating signal to audible and visible warning devices 28, 29, the timer also being connected to the low-limit detector 24, which prevents opening of valve 121, 122 unless the low pressure limit is exceeded for a given length of time set by said timer, and a high-limit pressure detector 25 connected to the sensor and to a highlimit switch 27 actuable to send a flow signal to the warning devices if the high-limit is exceeded. A supply pressure detector 15 is also provided which actuates the warning devices if the supply pressure drops below a predetermined level. Each of the three different alarm conditions is characterised by the nature of the sound and visual warning, an uninterrupted warning indicating low pressure supply, a warning which is interrupted at the rate of the breathing frequency indicating pressure in the airway exceeding a desired level, and a warning with rapid interruptions or, alternatively, a periodic short warning, indicating that the airway pressure exceeds a higher desired level. A pressure relief valve 190 is connected to the detectors 24, 25 by a conduit 22, also connected to sensor 23, for relieving pressure in excess of a predetermined value. A filter 30 may be provided in the inlet 18 of the regulator.