Patent US2400384A successfully refreshed from Google Patents.
US3600933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for determining the freezing point of a solution
Assignee: Emerson Process Management Ltd
•
Filing: 1970-03-27
•
Granted: 1971-08-24
•
Expires: 1990-03-27
Abstract
Abstract Apparatus for determination of the freezing point of a liquid or solution has a probe extending into the liquid which is cooled by a coolant circulated in the probe and with a resistance-type temperature sensor to sense the temperature of the mantle of solid forming on the probe. The probe is mechanically vibrated to prevent supercooling and means are provided for sensing the thickness of the mantle and controlling the coolant circulation to maintain an equilibrium condition with a mantle of constant thickness. The thickness of the mantle may be sensed by measuring an electrical parameter of the solid/liquid material between two electrodes on the probe but preferably it is determined by sensing the change in the mechanical resonant frequency of the probe, the probe being vibrated at its natural resonant frequency.
Inventors
- 👤 James Stewart Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:38
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/02; G01N25/04
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
89 words
Apparatus for the determination of the freezing point of a liquid comprising a probe adapted to be at least partially immersed in the liquid, means for vibrating said probe, means for cooling the probe and means responsive to the thickness of solidified material deposited on the probe for providing an output related to said thickness that operatively controls the cooling means to control the cooling so as to establish equilibrium conditions with a mantle of solidified material of constant thickness, and means for measuring the temperature of the mantle
Claim 2
Dependent Claim
89 words
Apparatus for the determination of the freezing point of a liquid comprising a probe adapted to be at least partially immersed in the liquid, means for vibrating said probe, means for cooling the probe and means responsive to the thickness of solidified material deposited on the probe for providing an output related to said thickness that operatively controls the cooling means to control the cooling so as to establish equilibrium conditions with a mantle of solidified material of constant thickness, and means for measuring the temperature of the mantle
Claim 3
Dependent Claim
44 words
Apparatus as claimed in claim 1 wherein said means responsive to the thickness of the solidified material on the probe comprises a pair of electrodes protruding slightly from the probe surface and means for measuring an electrical parameter of the material between the electrodes.
Claim 4
Dependent Claim
17 words
Apparatus as claimed in claim 2 wherein the means for measuring an electrical parameter comprises conductivity-measuring means.
Claim 5
Dependent Claim
33 words
Apparatus as claimed in claim 1 wherein said means responsive to the thickness of the solidified material on the probe comprises means responsive to change in the mechanical resonant frequency of the probe.
Claim 6
Dependent Claim
56 words
Apparatus as claimed in claim 4 wherein an additional element is provided adjacent the probe whereby, as the solid mantle builds up, it attaches the probe to said additional element, thereby changing the resonant frequency and wherein the means for measuring the temperature of the mantle comprises a temperature sensor on or in said additional element.
Claim 7
Dependent Claim
26 words
Apparatus as claimed in claim 1 wherein the means for measuring the temperature of the mantle comprises means to measure the surface temperature of the probe.
Claim 8
Dependent Claim
27 words
Apparatus as claimed in claim 1 wherein said probe is hollow and wherein the means for cooling the probe comprise means for circulating a coolant through it.
Claim 9
Dependent Claim
26 words
Apparatus as claimed in claim 7 wherein the coolant is circulated through an open-ended inner tube in the probe and back around outside said inner tube.
Claim 10
Dependent Claim
49 words
Apparatus as claimed in claim 7 wherein the probe is vibrated in an axial or torsional mode. 10 Apparatus as claimed in claim 1 wherein the probe is an elongate member extending completely through a vessel for containing the liquid and wherein a transverse mode of vibration is employed.
Claim 11
Dependent Claim
18 words
Apparatus as claimed in claim 1 wherein the probe is a rod cooled by a Peltier effect device.
Claim 12
Dependent Claim
39 words
Apparatus as claimed in claim 1 wherein the probe is formed of a piezoelectric material and wherein the means for vibrating it comprise means for applying an alternating electric potential to electrodes on the probe to vibrate it piezoelectrically.
Claim 13
Dependent Claim
19 words
Apparatus as claimed in claim 1 wherein the probe is formed of a magnetostrictive material and is vibrated magnetostrictively.
Claim 14
Dependent Claim
25 words
Apparatus as claimed in claim 1 wherein the probe is vibrated by an electronic oscillator using the probe as the frequency-determining component of the oscillator.
Claim 15
Dependent Claim
24 words
Apparatus as claimed in claim 14 wherein said oscillator comprises an amplifier amplifying signals from a pickup transducer sensing the vibration of the probe.
Claim 16
Dependent Claim
103 words
Apparatus for the determination of the freezing point of a liquid comprising a probe adapted to be at least partially immersed in the liquid, means for vibrating said probe at its resonant frequency, means for cooling the probe and means responsive to the change in resonant frequency due to solidified material forming on the probe, which responsive means provides on output related to said change that operatively controls the cooling means to control the cooling to establish a constant resonant frequency and establish equilibrium conditions with a mantle of solidified material of constant thickness, and means for measuring the temperature of the mantle.
Claim 17
Dependent Claim
103 words
Apparatus for the determination of the freezing point of a liquid comprising a probe adapted to be at least partially immersed in the liquid, means for vibrating said probe at its resonant frequency, means for cooling the probe and means responsive to the change in resonant frequency due to solidified material forming on the probe, which responsive means provides on output related to said change that operatively controls the cooling means to control the cooling to establish a constant resonant frequency and establish equilibrium conditions with a mantle of solidified material of constant thickness, and means for measuring the temperature of the mantle.
Claim 18
Dependent Claim
61 words
Apparatus as claimed in claim 16 and wherein the means responsive to change in resonant frequency comprises a reference oscillator which oscillates at a frequency slightly different from that of the probe, and means producing an output signal by mixing a signal from the reference oscillator with a signal at the probe oscillation frequency obtained from the probe or probe drive.
Claim 19
Dependent Claim
25 words
Apparatus as claimed in claim 17 wherein said reference oscillator comprises a further probe to be immersed in the solution but which is not cooled.
Claim 20
Dependent Claim
16 words
Apparatus as claimed in claim 18 wherein said probe and said further probe are mechanically similar.
References Cited (Backward Citations)
US3341835A
Cited
US3541540A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |