Apparatus and method for sensing a liquid with a single wire transmission line
First Claim
Patent Images
1. An apparatus for sensing a liquid comprising:
- means for generating baseband probe pulses of subnanosecond duration;
transition means coupled to said probe pulse generator means for converting a coaxial transmission line to a single wire transmission line, said single wire transmission line extending substantially perpendicularly to the surface of said liquid and extending therethrough, said wire providing a means for conducting said probe pulse to said liquid surface and for conducting reflections of said probe pulse from said liquid surface to said transition means;
coarse level increment generator means for producing pulses at a periodic rate in response to a probe pulse coupled from said probe pulse generator means, said periodic pulses defining a sequence of predetermined time intervals within which each time interval is representative of a coarse level increment for said liquid level measurement;
coarse level increment selector means for providing a selector pulse representative of one of said coarse range increments, one selector pulse generated for each probe pulse generated by said probe pulse generator means with each of said selector pulses representative of a predetermined coarse level increment;
gating means, having input terminals coupled to said coarse level increment generator means and to said coarse level increment selector means, for providing a trigger pulse at an output terminal when one of said periodic pulses and said selector pulse are simultaneously coupled to said input terminal; and
fine level readout means, having a first input terminal coupled to said transition means to receive said reflected probe pulse and a second input terminal coupled to said output terminal of said gating means, for determining a fine level within the one of said coarse level increments selected by said coarse level increment selector in response to said trigger pulse coupled from said gating means and said reflected probe pulse coupled from said transition means.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for measuring the level and dielectric constant of a liquid which includes a device for generating a subnanosecond baseband pulse that propagates through a transition device to a single wire transmission line that extends through an air filled region into the liquid. A discontinuity created at the air liquid interface produces a reflection of the baseband pulse that is compared with the transmitted pulse with respect to time of arrival and amplitude to determine the liquid level and the reflection coefficient at the air liquid interface. The reflection coefficient is then utilized to determine the dielectric constant of the liquid.
-
Citations
10 Claims
-
1. An apparatus for sensing a liquid comprising:
-
means for generating baseband probe pulses of subnanosecond duration; transition means coupled to said probe pulse generator means for converting a coaxial transmission line to a single wire transmission line, said single wire transmission line extending substantially perpendicularly to the surface of said liquid and extending therethrough, said wire providing a means for conducting said probe pulse to said liquid surface and for conducting reflections of said probe pulse from said liquid surface to said transition means; coarse level increment generator means for producing pulses at a periodic rate in response to a probe pulse coupled from said probe pulse generator means, said periodic pulses defining a sequence of predetermined time intervals within which each time interval is representative of a coarse level increment for said liquid level measurement; coarse level increment selector means for providing a selector pulse representative of one of said coarse range increments, one selector pulse generated for each probe pulse generated by said probe pulse generator means with each of said selector pulses representative of a predetermined coarse level increment; gating means, having input terminals coupled to said coarse level increment generator means and to said coarse level increment selector means, for providing a trigger pulse at an output terminal when one of said periodic pulses and said selector pulse are simultaneously coupled to said input terminal; and fine level readout means, having a first input terminal coupled to said transition means to receive said reflected probe pulse and a second input terminal coupled to said output terminal of said gating means, for determining a fine level within the one of said coarse level increments selected by said coarse level increment selector in response to said trigger pulse coupled from said gating means and said reflected probe pulse coupled from said transition means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method for determining the level of a contained liquid comprising the steps of:
-
exciting a first transmission line, immersed in said liquid, with a probe pulse of subnanosecond duration; generating a pulse, triggered by said probe pulse, to establish a coarse level increment; propagating said probe pulse and a reflection of said probe pulse, produced at said level of said contained liquid, along said first transmission line, to a level processor; triggering a first short pulse generator with said coarse level pulse; triggering a second short pulse generator with said reflected probe pulse; coupling said first and second short pulses to opposite ends of a second transmission line; determining the location along said second transmission line at which said first and second short pulses coalesce, thereby determining the fine level of said contained liquid; and displaying a visual indication of said level of said contained liquid.
-
Specification