Magnetic contamination detector
First Claim
1. Apparatus for detecting magnetisable electrically conductive particles in an electrically non-conductive fluid medium, including sensor means comprising:
- a plug shaped device having an axis and including means producing a magnetic flux in a flux path extending between two axially spaced apart electrode means electrically insulated one from the other and connectable to circuit means for signalling a condition in which an electrically conductive path is formed from one said electrode means to the other, the lines of force of said flux in said flux path extend substantially rectilinearly in an axial direction from one electrode to the other; and
said means for producing the magnetic flux are ferromagnetic means for directing substantially the balance of said flux in a loop path said balance being substantially confined within said ferromagnetic means thereby substantially to prevent nonrectilinear portions of said flux from exerting an influence on magnetisable particles, if any, arranged between said electrode means.
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Accused Products
Abstract
Apparatus is provided for detecting ferrous contamination in a fluid such as engine transmission lubricant. The apparatus has two spaced apart electrodes, a magnetic flux extending between the electrodes the lines of force of which are substantially rectilinear, the electrodes being connectable to a circuit for signalling when an electrically conductive path is formed from one electrode to the other by metal particles attracted to the flux and formed into an electrode spanning bridge. For preference the sensor is a hollow plug, which in use is screwed into a transmission housing port, and has a flat end wall in contact with the lubricant in the housing. The plug contains a magnet having both poles disposed towards the plug end wall, a portion of the end wall acting as one electrode. A ferromagnetic disc mounted externally from the plug end wall, and electrically insulated therefrom, overlies the poles. The disc acts as a second electrode and serves to direct the magnetic flux rectilinearly across the gap between the electrodes. The electrodes are connectable to circuit means whereby a change in interelectrode resistance may be detected.
40 Citations
19 Claims
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1. Apparatus for detecting magnetisable electrically conductive particles in an electrically non-conductive fluid medium, including sensor means comprising:
- a plug shaped device having an axis and including means producing a magnetic flux in a flux path extending between two axially spaced apart electrode means electrically insulated one from the other and connectable to circuit means for signalling a condition in which an electrically conductive path is formed from one said electrode means to the other, the lines of force of said flux in said flux path extend substantially rectilinearly in an axial direction from one electrode to the other; and
said means for producing the magnetic flux are ferromagnetic means for directing substantially the balance of said flux in a loop path said balance being substantially confined within said ferromagnetic means thereby substantially to prevent nonrectilinear portions of said flux from exerting an influence on magnetisable particles, if any, arranged between said electrode means. - View Dependent Claims (2, 3, 4, 5, 16, 17, 18, 19)
- a plug shaped device having an axis and including means producing a magnetic flux in a flux path extending between two axially spaced apart electrode means electrically insulated one from the other and connectable to circuit means for signalling a condition in which an electrically conductive path is formed from one said electrode means to the other, the lines of force of said flux in said flux path extend substantially rectilinearly in an axial direction from one electrode to the other; and
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6. Apparatus for detecting magnetisable electrically conductive particles in an electrically non-conductive fluid medium, including sensor means comprising:
- a plug shaped device having an axis and including means producing a magnetic flux in a flux path extending between two axially spaced apart electrode means electrically insulated one from the other and connectable to circuit means for signalling a condition in which an electrically conductive path is formed from one said electrode means to the other, the lines of force of said flux in said flux path extend substantially rectilinearly in an axial direction from one electrode to the other;
said means producing a magnetic flux comprises;
two coplanar magnetic pole faces, one spaced laterally apart from, and of opposite polarity to, the other and a ferromagnetic body overlying both said faces and spaced apart therefrom, whereby a magnetic flux extends in a path from one said pole face to said ferromagnetic body, along said body and then to said other pole face, the lines of force of said flux extending substantially rectilinearly between said body and each said pole face. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
- a plug shaped device having an axis and including means producing a magnetic flux in a flux path extending between two axially spaced apart electrode means electrically insulated one from the other and connectable to circuit means for signalling a condition in which an electrically conductive path is formed from one said electrode means to the other, the lines of force of said flux in said flux path extend substantially rectilinearly in an axial direction from one electrode to the other;
Specification