APPARATUS FOR INCIDATING RATE OF ICE ACCRETION

摘要

ABSTRACT OF THE DISCLOSUREApparatus for indicating rate of ice accretion part-icularly for use in an aircraft, the apparatus including testsurface on which ice forms in use. First and second gas conduitsare supplied with gas from a common pressure regulator theinlet of which communicates with a gas supply. A control port ofthe regulator is supplied with a reference pressure signal andthe regulator operates to maintain its outlet pressure at a pre-determined amount in excess of the reference pressure. Each ofthe first and second conduits includes a restrictor and eachconduit terminates at its end remote from the regulator in anorifice. The first orifice is adjacent the test surface and apressure difference sensor is associated with the first andsecond conduits to produce a signal dependent on the pressuredifference at points between the orifice and restrictor of thetwo conduits. The pressure difference signal is applied to anindicator. A control conduit connects the control port of theregulator to the second conduit at a point which is intermediatethe orifice and the restrictor of the second conduit so that thereference pressure for the regulator is derived from the secondconduit between the restrictor and the orifice thereof. The testsurface is moved relative to the first orifice at a predeterminedspeed and thus the first orifice will be restricted to an amountdependent upon the thickness of ice forming on the test surface.The difference in pressure sensed by the sensor is directlyrelated to the thickness of the ice layer on the test surface,and since the test surface is moving at a predetermined speedthen the indicator indicates the rate of ice accretion on thetest surface.