US4028932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photo acoustic cell
Assignee: Hoffmann La Roche Inc
•
Filing: 1975-04-14
•
Granted: 1977-06-14
•
Expires: 1995-04-14
Abstract
Abstract Three embodiments of an improved photo acoustic cell for use in analyzing solid and quasi-solid samples are disclosed. Each cell includes a sample holding chamber having one wall or portion of one wall thereof made from a light transparent material. The sample holding chamber in each embodiment is connected to a microphone by a thin tube which renders the cell, which includes the chamber tube and microphone, an acoustical resonant structure at a frequency within the response characteristics of the microphone. In one embodiment, means are disclosed for pressuring the inside of the cell as well as equalizing the pressure on the outside of the tube. In a second embodiment, the sample to be analyzed forms a portion of the cavity walls and means are provided for reducing the pressure in the cavity to hold the sample securely to the remaining structure for defining the cavity. In this embodiment a fiber optic element brings the light into the chamber. In the third embodiment the cell is mounted relative to a support structure so that different portions of the sample can be brought into relationship with can advantageously be employed to analyze plates, paper or the like which result from chromatographic techniques.
Inventors
- 👤 Allan Rosencwaig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:01
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/1702
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
110 words
An apparatus for use in analyzing a solid or quasi-solid sample including: first means for defining a sample chamber to hold said sample to be analyzed and for enclosing a fluid therein; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; second means responsive to pressure variations in said fluid for providing an electrical signal; third means for fluidly connecting said sample chamber to said second means; said third means having a volume between one half and ten times said predetermined volume; and said predetermined volume being between 1 and 50 cubic centimeters.
Claim 2
Independent Claim
110 words
An apparatus for use in analyzing a solid or quasi-solid sample including: first means for defining a sample chamber to hold said sample to be analyzed and for enclosing a fluid therein; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; second means responsive to pressure variations in said fluid for providing an electrical signal; third means for fluidly connecting said sample chamber to said second means; said third means having a volume between one half and ten times said predetermined volume; and said predetermined volume being between 1 and 50 cubic centimeters.
Claim 3
Dependent Claim
23 words
The apparatus as defined in claim 1 in which said third means is a passageway having a clearance between 0.02 and 0.20 centimeters.
Claim 4
Dependent Claim
30 words
The apparatus as defined in claim 1 in which said first, second and third means defines an acoustic resonant structure having a fundamental frequency of between 100 and 1,000 hertz.
Claim 5
Dependent Claim
23 words
The apparatus as defined in claim 3 in which said third means is a tube having a radius between 0.01 and 0.10 centimeters.
Claim 6
Dependent Claim
24 words
The apparatus as defined in claim 1 in which said volume of said third means is between one-half and two times said predetermined volume.
Claim 7
Dependent Claim
22 words
The apparatus as defined in claim 1 in which said volume of said third means is substantially equal to said predetermined volume.
Claim 8
Dependent Claim
20 words
The apparatus as defined in claim 1 in which said sample forms a part of said sample chamber defining means.
Claim 9
Dependent Claim
25 words
The apparatus as defined in claim 7 also including: an optical fiber for bringing light to said portion of said first means which passes light.
Claim 10
Dependent Claim
25 words
The apparatus as defined in claim 1 also including a support structure; and said first means is mounted for movement relative to said support structure.
Claim 11
Dependent Claim
23 words
The apparatus as defined in claim 9 in which said third means is a tube having a clearance between 0.02 and 0.20 centimeters.
Claim 12
Dependent Claim
30 words
The apparatus as defined in claim 10 in which said first, second and third means define an acoustic resonant structure having a fundamental frequency of between 100 and 1,000 hertz.
Claim 13
Dependent Claim
19 words
The apparatus as defined in claim 1 also including: means for applying gas under pressure to said sample chamber.
Claim 14
Dependent Claim
26 words
The apparatus as defined in claim 12 in which said applied gas has a ratio of specific heats (C p /C v ) greater than air.
Claim 15
Independent Claim
124 words
An apparatus for use in analyzing a solid or quasi-solid sample in which said sample forms a part of said sample chamber defining means including: first means for defining a sample chamber to hold said sample to be analyzed and for enclosing a fluid therein; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; second means responsive to pressure variations in said fluid for providing an electrical signal; third means for fluidly connecting said sample chamber to said second means; said third means having a volume between one half and ten times said predetermined volume; and means for maintaining the pressure in said chamber below 1 atmosphere.
Claim 16
Independent Claim
124 words
An apparatus for use in analyzing a solid or quasi-solid sample in which said sample forms a part of said sample chamber defining means including: first means for defining a sample chamber to hold said sample to be analyzed and for enclosing a fluid therein; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; second means responsive to pressure variations in said fluid for providing an electrical signal; third means for fluidly connecting said sample chamber to said second means; said third means having a volume between one half and ten times said predetermined volume; and means for maintaining the pressure in said chamber below 1 atmosphere.
Claim 17
Dependent Claim
23 words
The apparatus as defined in claim 14 in which said third means is a passageway having a clearance between 0.02 and 0.20 centimeters.
Claim 18
Dependent Claim
30 words
The apparatus as defined in claim 15 in which said first, second and third means defines an acoustic resonant structure having a fundamental frequency of between 100 and 1,000 hertz.
Claim 19
Dependent Claim
19 words
The apparatus as defined in claim 16 in which said predetermined volume is between 1 and 50 cubic centimeters.
Claim 20
Dependent Claim
27 words
The apparatus as defined in claim 14 also including: an optical fiber for bringing radiant energy to said portion of said first means which passes radiant energy.
Claim 21
Independent Claim
98 words
An apparatus for analyzing a solid or quasi-solid sample including: first means for defining a sample chamber to hold said sample to be analyzed; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; said predetermined volume being less than 50 cubic centimeters; second means responsive to pressure variations in a fluid for providing an electrical signal; and third means for fluidly connecting said sample chamber to said second means; said third means having a volume less than twice said predetermined volume.
Claim 22
Independent Claim
98 words
An apparatus for analyzing a solid or quasi-solid sample including: first means for defining a sample chamber to hold said sample to be analyzed; said sample chamber defining means including a portion thereof for passing radiant energy having a periodically varying magnitude; said sample chamber defined having a predetermined volume; said predetermined volume being less than 50 cubic centimeters; second means responsive to pressure variations in a fluid for providing an electrical signal; and third means for fluidly connecting said sample chamber to said second means; said third means having a volume less than twice said predetermined volume.
Claim 23
Dependent Claim
23 words
The apparatus as defined in claim 19 in which said third means is a passageway having a clearance between 0.02 and 0.20 centimeters.
Claim 24
Dependent Claim
30 words
The apparatus as defined in claim 20 in which said first, second and third means defines an acoustic resonant structure having a fundamental frequency of between 100 and 1,000 hertz.
Claim 25
Dependent Claim
25 words
The apparatus as defined in claim 19 also including a support structure; and said first means is mounted for movement relative to said support structure.
Claim 26
Dependent Claim
19 words
The apparatus as defined in claim 19 also including: means for applying gas under pressure to said sample chamber.
Claim 27
Dependent Claim
26 words
The apparatus as defined in claim 23 in which said applied gas has a ratio of specific heats (C p /C v ) greater than air.
Claim 28
Dependent Claim
20 words
The apparatus as defined in claim 19 in which said sample forms a part of said sample chamber defining means.
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) | 1980-06-13 | 1980-12-13 | 1981-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-13 | 1984-12-13 | 1985-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-13 | 1988-12-13 | 1989-06-14 | $7700.00 | Window Closed / Lapsed |