GB875437A - Electronic level sensing apparatus - Google Patents
Electronic level sensing apparatusInfo
- Publication number
- GB875437A GB875437A GB3232/60A GB323260A GB875437A GB 875437 A GB875437 A GB 875437A GB 3232/60 A GB3232/60 A GB 3232/60A GB 323260 A GB323260 A GB 323260A GB 875437 A GB875437 A GB 875437A
- Authority
- GB
- United Kingdom
- Prior art keywords
- probe
- servomotor
- oscillator
- signal
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
- G01F23/245—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid with a probe moved by an auxiliary power, e.g. meter, to follow automatically the level
Landscapes
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
875,437. Determining liquid level. GILBERT & BARKER MFG. CO. Jan. 29, 1960 [Feb. 3, 1959], No. 3232/60. Class 37. Level sensing apparatus for measuring the height of the upper and lower surfaces of a liquid p, e.g. petroleum in a tank, comprises a probe 10 suspended but insulated from a perforated metal tape 12 which passes over pulleys to a pin wheel 20 rotated by a servomotor 68 whereby the probe may be raised or lowered into a predetermined positional relationship with the upper or lower surface according to variations in the resonance frequency of the probe, and selective means whereby the frequency of an oscillator feeding the head may be varied so that the probe seeks one or the other surface in the manner described in Specification 750,858. The probe itself contains an antenna 48 shielded by a casing 50 which is filled with a dielectric material 82 such as an epoxy resin loaded with small glass beads. The antennµ 4 which is a quarter wavelength extends about # of an inch beyond the casing and carries a disc at its end for greater sensitivity, the standing wave being detected by a semi-conductor 52 and a 50-cycle wave with which the H.F. is modulated, being returned over a coaxial cable 24 which has served also to deliver the H.F. power to the electronic housing 18. The H.F. signal developed in oscillator 28 is coupled to the antennµ via loops 30, 31, 38, 46 and the return signal is confined to the desired path to amplifier 60 by capacitors 42, 44, 62 and inductive resistors 56, 58. The output of amplifier 60 is compared in comparator 64 with a reference voltage from the secondary of transformer T and the resulting signal is impressed on one winding 66 of a 2-phase induction servomotor 68, the other winding 70 being mains energized. If the probe is in air, the servomotor rotates, lowering it to contact the liquid whereby the wire 48 is detuned and the return signal is reduced until the probe reaches a predetermined position relative to the surface when the signal has an intermediate value equal to the reference value, the height of the surface being indicated by the angular position of the servomotor shaft. To cause the probe to seek the lower surface f either an interface between it and an immiscible liquid, e.g. water, or merely the bottom of the tank, the frequency of the oscillator is reduced by switching in capacitor 76, and the servomotor is caused to lower the probe to a new position e.g. “ inch above the lower surface where it avoids the scum, where the head is detuned further until the servomotor is stopped. Changes in the oscillator frequency can be made gradually by means of a variable condenser or in increments to avoid moving the probe in the wrong direction. When relay 78 is de-energized the probe seeks the upper surface. To overcome difficulty arising from the effects of humidity on the probe the probe is kept immersed and is raised to reach the height of the upper surface. The probe may be driven to the immersed position by connecting condenser 84 across the servomotor or by opening a switch 88 in the reference voltage feed. When probes of extremely high Q are used for greater accuracy, a modified circuit, Fig. 7 (not shown), is used. It includes a double triode preamplifier with degenerative feedback, in which the feedback can be disconnected for a short interval determined by a condenser discharge circuit, relay 78 which is energized from a remote source to lower the probe to the interface opening the feedback path to allow greater amplification of the signal during the initial immersion. A variable capacitor can be connected across the oscillator induction loop for calibration and tolerance compensation purposes or alternatively capacitor 76 may be used. Dimensions of parts and component values are given.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US875437XA | 1959-02-03 | 1959-02-03 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB875437A true GB875437A (en) | 1961-08-23 |
Family
ID=22205805
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB3232/60A Expired GB875437A (en) | 1959-02-03 | 1960-01-29 | Electronic level sensing apparatus |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB875437A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2183849A (en) * | 1985-12-09 | 1987-06-10 | Geotronics Metaltech Ab | Device for the detection of slag level in a molten metal bath |
DE3832763A1 (en) * | 1987-09-28 | 1989-04-06 | Geotronics Ab | DEVICE FOR DETECTING THE LEVEL OF A SLAG LIMIT LAYER IN A METAL MELT |
CN101713681B (en) * | 2009-12-02 | 2012-03-14 | 张学文 | Mining material detection circuit and device |
CN107024335A (en) * | 2016-02-01 | 2017-08-08 | 上海河口海岸科学研究中心 | A kind of vertical parameter test method and its device for wave current flume test |
-
1960
- 1960-01-29 GB GB3232/60A patent/GB875437A/en not_active Expired
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2183849A (en) * | 1985-12-09 | 1987-06-10 | Geotronics Metaltech Ab | Device for the detection of slag level in a molten metal bath |
DE3832763A1 (en) * | 1987-09-28 | 1989-04-06 | Geotronics Ab | DEVICE FOR DETECTING THE LEVEL OF A SLAG LIMIT LAYER IN A METAL MELT |
US4880212A (en) * | 1987-09-28 | 1989-11-14 | Geotronics Metaltech Ab | Device for detecting the level of the slag in a metal pool |
CN101713681B (en) * | 2009-12-02 | 2012-03-14 | 张学文 | Mining material detection circuit and device |
CN107024335A (en) * | 2016-02-01 | 2017-08-08 | 上海河口海岸科学研究中心 | A kind of vertical parameter test method and its device for wave current flume test |
CN107024335B (en) * | 2016-02-01 | 2019-05-03 | 上海河口海岸科学研究中心 | A kind of vertical parameter test method and its device for wave current flume test |
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