초록 ▼

A liquid level sensor adapted to be installed inside a reservoir of a liquid to be monitored. The level sensor includes a float made from magnetic material which moves between two opposed end positions along a predetermined up-and-down path following the top surface level of the liquid. An a.c. coil

A liquid level sensor adapted to be installed inside a reservoir of a liquid to be monitored. The level sensor includes a float made from magnetic material which moves between two opposed end positions along a predetermined up-and-down path following the top surface level of the liquid. An a.c. coil driven by a pulse generator is located at one end of the float path such that the magnetic material of the float is closer to the coil at this one end of the path than at the opposite end, and is thus a variable part of the “core”of the coil which changes in response to the liquid level in the reservoir. The magnetic flux generated by the coil and/or its inductive reactance, also being a function of the variable core and thus a function of the liquid level, can be monitored electrically to provide an indication of the liquid level to an operator. The level sensor can be used to provide a signal at a predetermined level, or to provide an output which is proportional to the level of the liquid in the reservoir. It is adaptable to be used in hot and other hostile environments, and therefore has special application in the automotive industry to automatically monitor the oil level in the crankcase of an automobile. An electronic monitoring circuit is also disclosed which can be used with the level sensor to provide an indication of the liquid level to an operator. The circuit includes filter means which reduces the response of the circuit to transient indications due, for example, to movement or “sloshing”of the liquid in the reservoir.

대표청구항 ▼

A liquid level sensor adaptable for use in the oil reservior of an internal combustion engine comprising: a housing adapted to be removably mounted in a bottom wall of the liquid reservior and allowing the liquid of said reservior to flow therethrough; said housing having a top and bottom end, said

A liquid level sensor adaptable for use in the oil reservior of an internal combustion engine comprising: a housing adapted to be removably mounted in a bottom wall of the liquid reservior and allowing the liquid of said reservior to flow therethrough; said housing having a top and bottom end, said bottom end being closer to said bottom wall than said top end; a magnetic coil flux generator fixedly sercured to the top end of said housing; a float mounted for reciprocal movement with respect to said flux generator along a predetermined path between first and second positions within said housing as a function of the level of liquid in the reservior; a magnetic material within said housing and movable with said float and being in closer proximity to the flux generator when the float is at the first of said positions than when the float is at second of said positions, and being in sufficiently close proximity to said flux generator at said first position to significantly affect the flux generated by said flux generator as a function of the level of said generator; monitoring means responsive to variations in the operating characteristics of said flux generator; guide means to keep said float movable in said predetermined path, said guide means mounted coaxially with said magnetic coil flux generator, and extending from said flux generator downwardly through said housing, and said float having a guide receiving cavity coaxial with said guide means whereby said guide means coacts with said guide receiving cavity maintains said float movably in said predetermined path.