Apparatus for indicating rate of ice accretion

• US 4,095,456 A
• Filed: 05/27/1976
• Issued: 06/20/1978
• Est. Priority Date: 06/04/1975
• Status: Expired due to Term

• Current Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Edgington, Geoffrey
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Roskos, Joseph W.
• Application Number:
  US05/690,389
• Time in Patent Office: 754 Days
• Field of Search: 73/37, 73/37.5, 73/37.6, 73/37.7, 73/432 CR, 340/234, 137/81, 244/134 F
• US Class Current: 73/37.6
• CPC Class Codes: B64D 15/20 Means for detecting icing or initiating de-icing

Abstract

Apparatus for indicating rate of ice accretion particularly for use in an aircraft, the apparatus including test surface on which ice forms in use. First and second gas conduits are supplied with gas from a common pressure regulator the inlet of which communicates with a gas supply. A control port of the regulator is supplied with a reference pressure signal and the regulator operates to maintain its outlet pressure at a predetermined amount in excess of the reference pressure. Each of the first and second conduits includes a restrictor and each conduit terminates at its end remote from the regulator in an orifice. The first orifice is adjacent the test surface and a pressure difference sensor is associated with the first and second conduits to produce a signal dependent on the pressure difference at points between the orifice and restrictor of the two conduits. The pressure difference signal is applied to an indicator. A control conduit at a point which is intermediate the orifice and the restrictor of the second conduit so that the reference pressure for the regulator is derived from the second conduit between the restrictor and the orifice thereof. The test surface is moved relative to the first orifice at a predetermined speed and thus the first orifice will be restricted to an amount dependent upon the thickness of ice forming on the test surface. The difference in pressure sensed by the sensor is directly related to the thickness of the ice layer on the test surface, and since the test surface is moving at a predetermined speed then the indicator indicates the rate of ice accretion on the test surface.

Claims

1. Apparatus for indicating rate of ice accretion comprising test surface upon which ice forms in use, first and second gas conduits each communicating at one end with the outlet of a gas pressure regulator the inlet of which communicates with a gas supply, and the regulator having a control port whereby the regulator is supplied with a reference pressure, the regulator operating to maintain its outlet pressure at a predetermined amount in excess of the reference pressure, first and second restrictors in said first and second conduits respectively, said first and second conduits terminating at their ends remote from the regulator in first and second orifices respectively, said first orifice being adjacent, and presented to, the test surface, means sensing difference in the pressure in the first and second conduits intermediate their orifice and their restrictor respectively and supplying a signal dependent upon such pressure difference to an indicator to operate the indicator, a control conduit connecting the control port of the regulator to the second conduit at a point intermediate the second orifice and the second restrictor whereby the reference pressure for the regulator is the pressure existing in the second conduit intermediate the second restrictor and the second orifice and, means for moving the test surface relative to the first orifice at a predetermined speed, the arrangement being such that when no ice is present on the test surface then the first orifice is unrestricted, and there is no pressure difference between the first and second conduits but when ice forms on the test surface the ice obstructs the first orifice to an extent dependent upon the thickness of the ice layer on the test surface thus resulting in an increase in pressure in the first conduit downstream of the first restrictor related to the thickness of the ice layer on the test surface, the difference in pressure between the first and second conduits being sensed by the sensor, and since the pressure difference is directly related to the thickness of the ice layer on the moving test surface the indicator thus indicating the rate of ice accretion.

2. Apparatus as claimed in claim 1 wherein the test surface is a cylinder which is rotated at a known speed, said first orifice being adjacent to and presented to the cylindrical surface of the cylinder and the cylinder having associated therewith means for continuously removing ice from the test surface as the test surface has moved past the first orifice.