GB1520432A - Apparatus for providing information relating to the flow of a fluid - Google Patents

Abstract

1520432 Monitoring the flow of breath PURITAN-BENNETT CORP 29 Sept 1975 39752/75 Headings G1N(A) and GIN(E) In a device for monitoring the flow of breath in a tube, the breath linearly displaces sections of an apertured or foraminous plate 15 within the tube. The displacement is monitored by magnetic capacitative or optical means to provide information about possible pulmonary disorders. (The patient blows into the device at 1). The diaphragm 15 may take the form of a central foraminous portion, Fig. 8, joined to an outside ring by arcuate shaped arms 24, 25, 26, which allow for any movement due to the breath pressure. Alternatively the diaphragm may be of the form shown in Fig. 10 which has a centremount form of suspension Fig. 9 (not shown). The diaphragm can have a ring of ferromagnetic material about its periphery and may be mounted above an electrical core 16 Fig. 4. The core may comprise an "E-core" having a pair of electrically conductive coils 17 and 18. The coils are supplied with an A.C. voltage, and electric detecting means (not shown) are employed to determine the degree of imbalance of the inductances in two segments of the core. The detecting means provide an output signal proportional to the displacement of the diaphragm. In a capacitative method of measuring the displacement Fig. 11 (not shown) two pairs of annular capacitative plates (52), (50) and (51), (53) are used. Each "innermost" capacitative plate being attached to the diaphragm. The device is initially calibrated so that there is no difference in capacitance between the two sets of plates. The arrangement is monitored electronically and any subsequent imbalance during use is proportional to the diaphragm displacement.