US3724169A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delta t bar spectrometer
Assignee: Aero Vac Corp
•
Filing: 1970-02-19
•
Granted: 1973-04-03
•
Expires: 1990-02-19
Abstract
Abstract Analysis of constituents of the atmosphere, particularly in the range from 1 PPM to 1 PPB, requires a many-fold factor of concentration, such as 105, before normal detection and analysis measurement can occur. Gages are selectively condensed at temperatures in a gradient maintained along a thermally conductive surface in a vacuum chamber in a gas flowing at a rate adjusted to cause substantially complete separation of zones of condensation for the gas and its impurities or the contaminants and constituents of an atmosphere to be investigated. A temperature gradient is maintained along the exterior of a bar in a vacuum chamber or within a conductive tube through which the gas sample passes. Close control of gas flow diffusion rate, and condensing surface temperature is established between two fixed temperature points as in a tube cooled at one end by liquid nitrogen, for effective separation along the tube wall of constituents. Measurement of the composition of a flowing gas sample, after condensation, is effected through successive component evaporation either into a vacuum or into a carrier gas in a reverse flow to an apparatus such as a mass spectrometer, commencing at the low temperature end. The Delta T bar separates each of the constituents including trace contaminants in a gas to permit successive recovery of the purified or concentrated components in timed sequence according to a controlled temperature rise along the Delta T bar.
Inventors
- 👤 D Santeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:26
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/14
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
27 words
In the method of claim 1, said surface having a warm end at substantially ambient temperature and a cold end at substantially the temperature of liquid nitrogen.
Claim 2
Dependent Claim
15 words
In the method of claim 1, said warm end being at elevated temperature during condensation.
Claim 3
Dependent Claim
39 words
In the method of claim 1 said warm end being cooled for an interval after termination of gas flow to substantially the evaporation temperature for the last to condense gas collected, said surface then being warmed as a unit.
Claim 4
Dependent Claim
45 words
In the method of claim 1 said surface being warmed progressively therealong from said cold end through the temperature range from said cold end to said warm end without warming said surface at any region except at that region then at the lowest temperature therealong.
Claim 5
Dependent Claim
19 words
In the method of claim 1 said evaporated gases being withdrawn by exhausting into an evacuated region before measurement.
Claim 6
Dependent Claim
40 words
In the method of claim 1 said step of elevating the temperature comprising establishing thermal equilibrium at successive points therealong with a rising temperature function, and further elevating the temperature of other portions of the surface formerly at lower temperatures.
Claim 7
Dependent Claim
33 words
In the method of claim 1, the rate of flow being controlled to effect diffusion of gas mixture to said surface in not substantially more than 5*K of temperature gradient on said surface.
Claim 8
Dependent Claim
38 words
In the method of claim 1 the quantity of gas in said mixture and the rate of flow within a flow passage being adjusted to cause condensation of constituent gases to occur at discrete locations along said surface.
Claim 9
Dependent Claim
134 words
In the detection of gaseous contaminants in a sample of atmospheric gas the steps of, subjecting said sample to a progressively decreasing temperature by moving the sample along a thermally conducting surface held at a predetermined temperature gradient between upper and lower fixed temperatures at a heat source and heat sink, respectively, supplying heat at said source and withdrawing heat at said sink to maintain said temperature gradient until gases of the sample condensable at or above said lower temperature are condensed seriatim along said surface, providing a reverse flow of carrier gas from said lower temperature of said surface to said upper temperature, progressively raising the temperature of lower temperature portions of the surface to successively evaporate condensed gases, and detecting in succession quantities of gases evaporated in inverse order of their deposition.
Claim 10
Dependent Claim
21 words
In the method of claim 10, said sample being passed from ambient temperature to liquid nitrogen temperature along an elongated surface.
Claim 11
Dependent Claim
35 words
In the method of claim 10, said step of subjecting the sample to progressively decreasing temperature comprising flowing said sample through a walled passage in contact therewith between said heat source and said heat sink.
Claim 12
Dependent Claim
49 words
In the method of claim 10, said step of raising the temperature of lower temperature portions of the surface comprising controlling in succession the temperature at respectively warmer points along said surface according to said gradient during condensation while increasing the temperature of portions colder than said controlled points.
Claim 13
Dependent Claim
34 words
In the method of claim 13 said control in succession of warmer portions of the surface comprising equalizing the temperature of successive portions of surface with corresponding temperatures in a maintained reference temperature gradient.
Claim 14
Dependent Claim
69 words
In the method of claim 10 said sample being a residual gas in a vacuum chamber, said surface being held at a temperature gradient in an auxiliary passage extending along at least a substantial portion of the vacuum chamber and open thereto at one end, while exhaust pumping the passage at the other end to cause residual gas flow along said surface at a controlled rate of temperature decrease.
Claim 15
Dependent Claim
100 words
Apparatus for segregating quantities of gases in a mixture, comprising means including a conduit for conducting said mixture along a path, thermally conductive bar means presenting an elongated surface adjacent said path, heat flow means for progressively controlling the temperature of said bar means to provide therealong a temperature gradient comprehending the sequential condensation temperatures of said gases, means for controlling gas flow to govern the amount of the several gases condensing seriatim on said surface, and means for warming said bar means progressively from the low temperature end of the thermal gradient to evaporate said condensed gases in succession.
Claim 16
Dependent Claim
22 words
Apparatus accorDing to claim 16, said means controlling gas flow including conduit valves for controlling rate and amount of the mixture admitted.
Claim 17
Dependent Claim
21 words
Apparatus according to claim 16 including means for exhausting into an evacuated space the constituent gases as they are successively evaporated.
Claim 18
Dependent Claim
24 words
Apparatus according to claim 16 including means supplying a carrier gas flow in reverse direction along said path to convey evaporated gases in succession.
Claim 19
Dependent Claim
38 words
Apparatus according to claim 16, said means for warming the bar means including heat conductive means in thermal contact therewith at the low temperature end of said thermal gradient and means for progressively warming said heat conductive means.
Claim 20
Dependent Claim
43 words
Apparatus according to claim 20, said heat conductive means comprising a metallic member in thermal contact with and slidable along said bar, said means for warming comprising means for thermally engaging successive regions on a thermally conductive member held to a reference gradient.
Claim 21
Dependent Claim
48 words
Apparatus according to claim 16, said bar means comprising a solid metallic element extending from a first heat exchanger at one temperature to a second heat exchanger at a second temperature, one said temperature being below the boiling points of constituent gases to be condensed from the mixture.
Claim 22
Dependent Claim
34 words
Apparatus according to claim 22, said heat exchangers comprising liquid baths surrounding respective portions of said element, of which the liquids have higher and lower boiling points, respectively, than the gases of the mixture.
Claim 23
Dependent Claim
23 words
Apparatus according to claim 16, said bar means comprising a linear metallic tube connected to receive therein said gases passing along said path.
Claim 24
Dependent Claim
18 words
Apparatus according to claim 24 said tube having a length to diameter ratio not substantially less than 20.
Claim 25
Dependent Claim
34 words
Apparatus according to claim 24, including means for connecting said tube to a source of supply for said mixture during condensation and means for supplying a flowing carrier gas during evaporation of condensed gases.
Claim 26
Dependent Claim
26 words
Apparatus according to claim 24, said tube diameter being proportioned to rate of gas supply to provide a flow rate not substantially greater than 1.5 cm/sec.
Claim 27
Dependent Claim
15 words
Apparatus according to claim 24, said tube having a thermal gradient not over about 2*K/cm.
Claim 28
Dependent Claim
76 words
Apparatus according to claim 16, said bar comprising a thermal gradient tube, a second thermally conductive bar means having said thermal gradient maintained thereon by a heat source and a heat sink, said means for controlling the temperature of said bar means comprising a thermal conductor element connecting the second bar to said tube at the high temperature end and a second thermal conductor connecting the second bar to the tube at the low temperature end.
Claim 29
Dependent Claim
30 words
Apparatus according to claim 29, and means for moving said second thermal conductor progressively along the second bar to cause a rising temperature control at respective points on the tube.
Claim 30
Independent Claim
47 words
The method of isolating trace constituents of a gas mixture comprising subjecting said mixture to progressively lowered temperature in contact with a thermally conductive surface held to a fixed temperature gradient comprehending successive condensation temperatures of said constituents thereby to separatively remove said constituents from the mixture.
Claim 31
Independent Claim
74 words
The method of partially separating constituents of a residual gas in an enclosure comprising subjecting a region within said enclosure to a temperature gradient comprehending condensation temperatures for constituents to be separated by maintaining said gradient on a thermally conductive surface disposed in said region between points of heat supply to this surface and heat withdrawal from the surface, thereby to produce constituent condensations separately along portions of said surface according to temperature therealong.
Claim 32
Dependent Claim
84 words
Apparatus for segregating trace constituents of a progressively advanced vapor mixture, comprising thermally conductive bar means disposed adjacent thE path of vapor advancement in contact therewith, means including a heat source for fixing the temperature at the first end of said bar means, means including a heat sink for controlling the temperature at a second end of said bar means so as to establish a condensation temperature spacing along the bar means comprehending condensation temperatures for each of said trace constituents to be segregated.
Claim 33
Dependent Claim
23 words
Apparatus according to claim 33, including value means for controlling flow rate and dwell time of mixture portions advancing along the temperature gradient.
Claim 34
Dependent Claim
68 words
Apparatus according to claim 34, including means for stripping constituents deposited in succession along said gradient, being means for warming said bar means from the heat sink end toward the heat source end within a time interval made sufficiently small with respect to the interval during which advancing gas constituents are deposited to provide a desired factor of enrichment of said constituents as stripped from the bar means.
References Cited (Backward Citations)
US2398818A
Cited
US2813598A
Cited
US3064814A
Cited
US3225521A
Cited
US3225520A
Cited
US3398505A
Cited
US3589169A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |