Universal single point liquid level sensor
Abstract
A liquid level detector comprises a thermistor and circuitry for determining electrically if the thermistor is wet or dry and additionally, and continuously, if the thermistor is open or shorted. The voltage across the thermistor is filtered to remove low frequency electrical noise, then compared with a reference low voltage to determine if shorted and to a transition voltage chosen to be between the thermistor's normal wet and dry voltages to determine if the thermistor is wet or dry. The voltage is also compared to the supply voltage using a CMOS gate circuit element to determine if the thermistor is open. The gate passes both faults on to an LED to signal that a fault condition exists or indicates by another LED the wet or dry condition of the thermistor. A pump may be activated through a relay if the thermistor tests wet or dry, as desired. 1 figure.
- Inventors:
- Issue Date:
- OSTI Identifier:
- 7117659
- Patent Number(s):
- 5159318
- Application Number:
- PPN: US 7-598302
- Assignee:
- PTO; EDB-94-090522
- DOE Contract Number:
- AC09-76SR00001
- Resource Type:
- Patent
- Resource Relation:
- Patent File Date: 16 Oct 1990
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 47 OTHER INSTRUMENTATION; LEVEL INDICATORS; DESIGN; GATING CIRCUITS; LIGHT EMITTING DIODES; THERMISTORS; ELECTRONIC CIRCUITS; MEASURING INSTRUMENTS; SEMICONDUCTOR DEVICES; SEMICONDUCTOR DIODES; 440800* - Miscellaneous Instrumentation- (1990-)
Citation Formats
Kronberg, J W. Universal single point liquid level sensor. United States: N. p., 1992.
Web.
Kronberg, J W. Universal single point liquid level sensor. United States.
Kronberg, J W. Tue .
"Universal single point liquid level sensor". United States.
@article{osti_7117659,
title = {Universal single point liquid level sensor},
author = {Kronberg, J W},
abstractNote = {A liquid level detector comprises a thermistor and circuitry for determining electrically if the thermistor is wet or dry and additionally, and continuously, if the thermistor is open or shorted. The voltage across the thermistor is filtered to remove low frequency electrical noise, then compared with a reference low voltage to determine if shorted and to a transition voltage chosen to be between the thermistor's normal wet and dry voltages to determine if the thermistor is wet or dry. The voltage is also compared to the supply voltage using a CMOS gate circuit element to determine if the thermistor is open. The gate passes both faults on to an LED to signal that a fault condition exists or indicates by another LED the wet or dry condition of the thermistor. A pump may be activated through a relay if the thermistor tests wet or dry, as desired. 1 figure.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 27 00:00:00 EST 1992},
month = {Tue Oct 27 00:00:00 EST 1992}
}