Position responsive magnetic sensing elements for sensing the position of a member at a remote site
First Claim
1. Position-responsive apparatus comprising a series of magnetic field sensing elements successive members of which are disposed a first distance apart from each other alongside a path of relative movement of a non-contacting magnetic actuating means to act upon respective sensing elements by proximity thereto, said magnetic actuating means being separated from said sensing elements by a second distance, said apparatus including a magnetic flux concentrating element extending over substantially all of said first distance, between each adjacent pair of said series of sensing elements, wherein the flux concentrating elements act to direct the magnetic flux from the actuating means onto the sensing elements in a direction parallel to the path of relative movement of the actuating means, said sensing elements comprising solid-state Hall effect devices, the flux concentrating elements being selected from the group comprising ferrite members and members with a higher relative magnetic permeability than ferrite and said magnetic actuating means being separated from all of said solid-state Hall effect devices by a distance of at least 10 mm.
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Abstract
The effective operating range of an actuator magnet on a position detecting array of solid state hall effect devices improved by the use of flux concentrating elements which direct the flux along the array of sensing devices. The flux concentrating elements comprise a series of rods each avowing a magnetic permeability substantially greater than that of free space, such as soft ferrite, which are placed alignment with and between each sensing device in the array.
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Citations
14 Claims
- 1. Position-responsive apparatus comprising a series of magnetic field sensing elements successive members of which are disposed a first distance apart from each other alongside a path of relative movement of a non-contacting magnetic actuating means to act upon respective sensing elements by proximity thereto, said magnetic actuating means being separated from said sensing elements by a second distance, said apparatus including a magnetic flux concentrating element extending over substantially all of said first distance, between each adjacent pair of said series of sensing elements, wherein the flux concentrating elements act to direct the magnetic flux from the actuating means onto the sensing elements in a direction parallel to the path of relative movement of the actuating means, said sensing elements comprising solid-state Hall effect devices, the flux concentrating elements being selected from the group comprising ferrite members and members with a higher relative magnetic permeability than ferrite and said magnetic actuating means being separated from all of said solid-state Hall effect devices by a distance of at least 10 mm.
- 7. A method of increasing the effective range of detection of the position of a magnetic actuating means relative to a series of magnetic field sensing elements successive members of which are disposed a first distance apart from each other alongside a path of relative movement of the magnetic actuating means, said magnetic actuating means being separated from said sensing elements by a second distance, said method including the steps of positioning a flux concentrating element between each pair of said series of sensing elements and orienting the flux concentrating elements to direct the magnetic flux from the actuating means onto the sensing elements in a direction parallel to the path of relative movement of the actuating means, and said sensing elements comprising solid-state Hall effect devices, the magnetic flux concentrating elements being selected from the group comprising ferrite members and members with a higher relative magnetic permeability than ferrite and said magnetic actuating means being separated from all of said solid-state Hall effect devices by a distance of at least 10 mm, each said flux concentrating element extending over substantially all of said first distance between each pair of sensing elements.
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14. A liquid level sensing apparatus comprising a non-contacting magnetic actuating means, a liquid containing vessel, a temperature insulating material around the vessel, a series of magnetic field sensing elements disposed outside the temperature insulating material with said magnetic field sensing elements having successive members disposed a first distance apart from each other alongside a path of relative movement of said non-contacting magnetic actuating means to act upon respective sensing elements by proximity thereto, said magnetic actuating means being separated from said sensing elements by a second distance, said apparatus including a magnetic flux concentrating element extending over substantially all of said first distance, between each adjacent pair of said series of sensing elements, said sensing elements comprising solid-state Hall effect devices, the magnetic flux concentrating elements being selected from the group comprising ferrite members and members with a higher relative magnetic Permeability than ferrite and said magnetic actuating means being separated from all of said solid-state Hall effect devices by a distance of at least 10 mm wherein the flux concentrating elements act to direct the magnetic flux from the actuating means onto the sensing elements in a direction parallel to the path of relative movement of the actuating means.
Specification