Temperature-offsetting magnetically coupled pressure sender
First Claim
1. In a method for externally sensing pressure of a fluid within a pressure vessel including the steps of(a) locating and mounting for rotation, a magnetic field source inside of the pressure vessel containing the fluid for providing a magnetic field having an axis of symmetry rotating in a particular plane;
- (b) coupling the magnetic field source to a pressure activated bellows also located inside of the pressure vessel expanding and contracting responsive to pressure differences Δ
P between fluid pressure inside the pressure vessel and a known fluid pressure, the expansion and contraction of the bellows rotationally orienting the axis of symmetry of the provided magnetic field in the particular plane inside the pressure vessel;
(c) sensing orientation of the axis of symmetry of the provided magnetic field outside the pressure vessel; and
(d) correlating the orientation of the axis of symmetry of the magnetic field sensed to pressure within the pressure vessel, the improvement wherein;
said coupling the magnetic field source to a pressure activated bellows is by means of an intermediate member responsive to temperature within said pressure vessel.
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Accused Products
Abstract
A temperature compensating or offsetting magnetically coupled pressure sender comprises a pressure responsive element coupled to a rotating permanent magnet via a temperature sensitive element. The sender is intended to relay a pressure reading from within sealed vessels, including vehicle tires, without requiring penetration the wall of the vessel. In vehicular applications, the recommended pressure is usually stated for “cold” tires. Operating a vehicle heats up its tires and increases their pressure, which may produce a misleading indication. Pressure senders described in this invention have temperature compensating or offsetting elements built in to the pressure senders so that the indicated pressure is always referenced to a “cold” tire. Spiral or helical metallic strips or elastomeric members may be employed as the temperature compensating or offsetting elements.
9 Citations
9 Claims
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1. In a method for externally sensing pressure of a fluid within a pressure vessel including the steps of
(a) locating and mounting for rotation, a magnetic field source inside of the pressure vessel containing the fluid for providing a magnetic field having an axis of symmetry rotating in a particular plane; -
(b) coupling the magnetic field source to a pressure activated bellows also located inside of the pressure vessel expanding and contracting responsive to pressure differences Δ
P between fluid pressure inside the pressure vessel and a known fluid pressure, the expansion and contraction of the bellows rotationally orienting the axis of symmetry of the provided magnetic field in the particular plane inside the pressure vessel;
(c) sensing orientation of the axis of symmetry of the provided magnetic field outside the pressure vessel; and
(d) correlating the orientation of the axis of symmetry of the magnetic field sensed to pressure within the pressure vessel, the improvement wherein; said coupling the magnetic field source to a pressure activated bellows is by means of an intermediate member responsive to temperature within said pressure vessel. - View Dependent Claims (2, 3, 4)
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5. In a magnetically coupled pressure gauge for indicating fluid pressure within a pressure vessel outside the pressure vessel, comprising in combination,
(a) a rotatable sender means mounted inside the pressure vessel for providing a rotatable magnetic field having a specific direction, the specific direction of the magnetic field in the plane parallel to an axis of symmetry of the magnetic field; -
(b) a pressure actuated bellows mechanism also mounted inside of the pressure vessel coupled for rotating the sender means rotationally changing orientation of the specific direction of the magnetic field in a plane parallel to the axis of symmetry responsive to variations in fluid pressure within the vessel; and
(c) sensor means mounted outside of the pressure vessel for sensing and indicating orientation of the specific direction of the magnetic field provided by the sender means in a plane parallel its axis of symmetry as rotated to a particular orientation by the pressure actuated bellows mechanism, the improvement wherein; said pressure activated bellows mechanism is coupled for rotating said sender means rotationally includes an intermediate member responsive to temperature within said pressure vessel. - View Dependent Claims (6, 7, 8, 9)
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Specification