US 5,305,639 A · LPG gauge sensor

Abstract

A liquid petroleum gas (LPG) gauge sensor unit fits between the units of an existing magnetically-coupled LPG gauge and includes a magnetic field sensing switch, a mechanism to variably position the switch and an intermediate magnet. The intermediate magnet is positioned upon an axle-like mechanism upon which it is free to rotate and magnetically couples to the existing gauge base magnet which is, in turn, connected to a float that measures the liquid level. The existing indicator magnet in the gauge assembly magnetically couples with the intermediate magnet so that the gauge unit visually indicates the level of LPG within the LPG tank, despite the increased distance between the base and indicator magnets caused by the sensor unit. The magnetic field sensing switch is used to sense the position of the base or intermediate magnet and thereby sense the liquid level.

Claims16

Dependent claims

Sensor apparatus to be employed with a LPG gauge which measures an LPG level in a tank, said LPG gauge having a hermetic base unit connected to said tank, a base magnet located in said base unit, means for rotating said base magnet to an angular position corresponding to said LPG level, a hermetic indicator unit containing an indicator magnet which magnetically couples to said base magnet, a longitudinal axis along said base unit and said indicator unit, and an indicator element connected to said indicator magnet, said sensor apparatus comprising:

a hermetic housing having a shape which allows said housing to be mounted between said base unit and said indicator unit;
means located in said housing and responsive to the angular position of said base magnet for generating an indicative signal when said base magnet reaches a predetermined proximity to said generating means;
and
means for variably positioning said generating means relative to said base magnet to generate said indicative signal when said base magnet reaches a predetermined angular position.

1 more element

Sensor apparatus to be employed with an LPG gauge which measures an LPG level in a tank, said LPG gauge having a hermetic base unit connected to said tank, a base magnet located in said base unit, means for rotating said base magnet to an angular position corresponding to said LPG level, a hermetic indicator unit, an indicator magnet which magnetically couples to said base magnet located within said indicator unit, a longitudinal axis along said base unit and said indicator unit, and an indicator element connected to said indicator magnet, said sensor apparatus comprising:

magnetically responsive switch means responsive to said base magnet for generating an indicative signal when said base magnet reaches a predetermined proximity to said magnetically responsive switch means,
a rotatable unit and an alignment unit, each of said rotatable unit and said alignment unit having a shape which allows said units to be mounted between said base unit and said indicator unit, said alignment unit being connected to said base unit, said rotatable unit containing said magnetically responsive switch means, and said rotatable unit including means cooperating with said alignment unit to allow manual rotation of said rotatable unit about the longitudinal axis to bring said magnetically responsive switch means into a position where said magnetically responsive switch means generates said indicative signal when said base magnet reaches a predetermined angular position.

at least one intermediate magnet having sufficient magnetic strength to couple with said indicator magnet and said base magnet;
a magnet holder containing said at least one intermediate magnet;
an axis means disposed along said longitudinal axis, said magnet holder being rotatably mounted upon said axle means;
a Hall-Effect switch responsive to a magnetic field produced by said at least one intermediate magnet;
a polymeric material alignment ring connected to said first housing and having at least one tower protruding perpendicularly from the plane of said ring, said at least one tower having a protruding rib,
a circuit board, said Hall-Effect switch being mounted on said circuit board,
a polymeric material rotatable housing means having a hermetic, potted compartment and a hermetic, dry atmosphere compartment, said rotatable housing means having a shape to partially fit through and over said alignment ring thereby abutting said alignment ring, said rotatable housing means having semicircular slots through which said at least one tower protrudes, said semicircular slots allowing said rotatable housing means to be rotated about the longitudinal axis, said rotatable housing means including a series of grooves on a section of said rotatable housing means that abuts said alignment ring, said grooves having shape to be engageable by said rib, said hermetic, potted compartment containing said circuit board, said circuit board being connected to said rotatable housing means such that said Hall-Effect switch is offset from the longitudinal axis, said hermetic, dry atmosphere compartment containing said at least one intermediate magnet, said holder and said axle means.

4 more elements

Dependencies are inferred from the claim text.

LPG gauge sensor

Life of this patent

LPG gauge sensor

Life of this patent

Abstract

Claims16