Apparatus for measuring the flow-pressure characteristics of the gas passing through a product sample having two faces

摘要

An apparatus is provided for measuring the flow-pressure characteristics of a gas passing through a product sample with two faces, for example for measuring the permeability of a sample of air permeable material such as cigarette paper. A sample holder allows the external face of the paper to be exposed to atmospheric pressure and the internal face to a sub-atmospheric pressure created by a pump, whereas the value of this pressure difference and of the air flow passing through the sample is measured. A control system comprising a continuously controlled control valve and an electronic circuit controlled by a reference signal and a signal representative of the real pressure difference or of the real flow rate allows measurement conditions to be obtained rapidly in conformity with the requirements of certain standards and recommendations.