US3787874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making boundary-layer flow conditions visible
Assignee: Siemens AG
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Filing: 1972-07-07
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Granted: 1974-01-22
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Expires: 1992-07-07
Abstract
Abstract Boundary-layer flow conditions of gases are made visible by applying to the surface of a moving or stationary structural body to be exposed to the flow a reactive layer of at least one chemical color indicator, such as an acid-base indicator and/or a Redox indicator or a liquid-crystal indicator, such as a cholesterinic liquid. Then the body is exposed to a flow of gas, such as air, which gas may contain a reagent. The chemical color indicator can also be applied together with gelling means and a moisture binder. The chemical color indicator can also be absorbed by a high-contrast, absorbent paper which is then applied to the body. A metal or plastic foil coated with a binder and/or indicator can also be used for this purpose. A boundarylayer flow pattern image is produced, which can subsequently be recorded by known means.
Inventors
- 👤 G Urban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:11
CPC Classifications
G; G01; G01N; G01N13/00; Y; Y10; Y10T; Y10T137/00; Y10T137/206; Y10T137/2065
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
24 words
The method according to claim 1, and further comprising the additional step of recording the boundary-layer flow image after it has been made visible.
Claim 2
Dependent Claim
25 words
The method according to claim 1, and further comprising the additional step of photographing the boundary-flow image in color after it has been made visible.
Claim 3
Dependent Claim
30 words
The method according to claim 1 wherein the chemical color indicator is applied by binding it to a smooth absorbent paper and then applying the paper to the structural body.
Claim 4
Dependent Claim
57 words
The method according to claim 4 and further comprising the additional step of stripping said paper off the structural body after the structural body has been subjected to the gas flow and after a chemical color image of the boundary-layer flow has been produced on the paper, thereby providing a record of the flow on the paper.
Claim 5
Dependent Claim
16 words
The method according to claim 1 wherein the chemical color indicator applied is an acid-base indicator.
Claim 6
Dependent Claim
30 words
The method according to claim 6 and further comprising the additional steps of mixing a buffer with the acid-base indicator prior to applying the acid-base indicator to the structural body.
Claim 7
Dependent Claim
31 words
The method according to claim 6 and further comprising the additional step of mixing an alkaline buffer with the acid-base indicator prior to applying the acid-base indicator to the structural body.
Claim 8
Dependent Claim
31 words
The method according to claim 6 and further comprising the additional step of mixing an acid buffer with the acid-base indicator prior to applying the acid-base indicator to the structural body.
Claim 9
Dependent Claim
16 words
The method according to claim 1 wherein the chemical color indicator applied is a Redox indicator.
Claim 10
Dependent Claim
16 words
The method according to claim 1 wherein the chemical color indicator applied is a liquid-crystal indicator.
Claim 11
Dependent Claim
33 words
The method according to claim 11 wherein the liquid-crystal indicator is applied by spraying it on thinly in a low-boiling solvent whereby the solvent evaporates, leaving a dry film on the structural body.
Claim 12
Dependent Claim
15 words
The method according to claim 11 wherein the liquid-crystal indicator applIed is a cholesterinic liquid.
Claim 13
Dependent Claim
30 words
The method according to claim 1 and further comprising the additional step of adding a reagent to the gas flow prior to subjecting the structural body to the gas flow.
Claim 14
Dependent Claim
18 words
The method according to claim 14 wherein the reagent is added in gaseous form to the gas flow.
Claim 15
Dependent Claim
24 words
The method according to claim 15 wherein the reagent is added to the gas flow by conducting the gas flow over the gaseous reagent.
Claim 16
Dependent Claim
27 words
The method according to claim 14 wherein the reagent is added to the gas flow by bubbling the gas flow through an aqueous solution of the reagent.
Claim 17
Dependent Claim
18 words
The method according to claim 1 wherein the chemical color indicator applied is applied in a moisture-retaining additive.
Claim 18
Dependent Claim
23 words
The method according to claim 1 wherein the chemical color indicator is applied in combination with a gelling agent and a moisture retainer.
Claim 19
Dependent Claim
29 words
The method according to claim 1 and further comprising the additional step of applying a foil to the structural body prior to subjecting the body to the gas flow.
Claim 20
Dependent Claim
28 words
The method according to claim 20 and further comprising the additional step of coating the foil with a binding agent prior to applying the foil to the body.
Claim 21
Dependent Claim
30 words
The method according to claim 1 and further comprising the additional step of applying a metal foil to the structural body prior to subjecting the body to the gas flow.
Claim 22
Dependent Claim
30 words
The method according to claim 1 and further comprising the additional step of applying a plastic foil to the structural body prior to subjecting the body to the gas flow.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |