Apparatus for use in the measurement of the flow rate of fluid flow

摘要

A fluidic flowmeter for measuring the respiratory function of infants or children comprises a duct through which the infant or child breathes. A convergent pair of supply passages are provided for directing a pair of jets across the duct towards a pair of receiver passages which communicate with and diverge from the duct, the jets merging part way across the duct. A pressure tapping is provided in each receiver passage for sensing the static pressure of fluid flow at a respective point in each receiver passage and there is a differential pressure sensitive transducer having an input connected to one end of the pressure tappings and another input connected to the other pressure tapping. In a preferred embodiment the two receiver passages are connected together to define a loop, the dimensions and configuration of that part of the loop with which the tappings communicate being such that the flow passed each tapping is laminar. A temperature sensitive electrical resistance element or a hot-wire anemometer element may be used in place of the pressure tappings to provide a signal which is indicative of non-turbulent fluid flow through the receiver passages if the receiver passages are sized and configured to ensure laminar flow therethrough.