US4607228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for measuring the concentration of solid particles in a fluid stream
Assignee: Battelle Development Corp
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Filing: 1984-01-13
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Granted: 1986-08-19
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Expires: 2004-01-13
Abstract
Abstract Apparatus for measuring the concentration of solid particles in a fluid stream wherein a critical flow orifice produces a stream of fluid having a constant velocity, a surface for effecting triboelectric charging of the particles in the gas in the constant velocity stream and a charge measuring device for measuring the charges thus triboelectrically imparted to the particles. The apparatus overcomes the inaccuracies which occur in prior art particle detectors when such particle detectors are used to monitor fluid streams whose velocity is variable e.g. air intake systems for internal combustion engines which operate at varying speeds.
Inventors
- 👤 Robert B. Reif
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:00
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/06; G01N15/0656; G01N27/00; G01N27/60
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
84 words
Apparatus for measuring the concentration of solid particles in a fluid stream, said apparatus comprising: means for producing a sub-stream of fluid, means for producing a substantially constant velocity in said sub-stream which is independent of the velocity of said fluid stream; a triboelectric charging surface disposed such that particles in said sub-stream can impact upon said surface, thereby effecting triboelectric charging of said particles impacting upon said surface; and charge measuring means for measuring the charge produced on said particles by said impacts.
Claim 2
Dependent Claim
84 words
Apparatus for measuring the concentration of solid particles in a fluid stream, said apparatus comprising: means for producing a sub-stream of fluid, means for producing a substantially constant velocity in said sub-stream which is independent of the velocity of said fluid stream; a triboelectric charging surface disposed such that particles in said sub-stream can impact upon said surface, thereby effecting triboelectric charging of said particles impacting upon said surface; and charge measuring means for measuring the charge produced on said particles by said impacts.
Claim 3
Dependent Claim
28 words
Apparatus according to claim 1 wherein said charge measuring means includes an electrode and said triboelectric charging surface comprises at least part of the surface of said electrode.
Claim 4
Dependent Claim
35 words
Apparatus according to claim 1 wherein a conduit is provided to receive said part of said fluid flow and wherein said triboelectric charging surface comprises a curved portion of the internal surface of said conduit.
Claim 5
Dependent Claim
54 words
Apparatus according to claim 1 wherein said sub-stream producing means comprises a conduit member having walls defining a critical flow orifice through which said sub-stream of fluid can pass, said orifice being upstream of the triboelectric charging surface, and means for producing a pressure drop across said orifice sufficient to ensure critical flow therethrough.
Claim 6
Dependent Claim
35 words
Apparatus according to claim 4 wherein said means for producing a pressure drop comprises a pump through which said sub-stream of fluid is arranged to pass after said sub-stream has passed said charge measuring means.
Claim 7
Dependent Claim
18 words
Apparatus according to claim 4 wherein said critical flow orifice has a diameter not exceeding about 1 mm.
Claim 8
Dependent Claim
18 words
Apparatus according to claim 6 wherein said critical flow orifice has a diameter not exceeding about 0.5 mm.
Claim 9
Dependent Claim
15 words
Apparatus according to claim 1 wherein said sub-stream producing means includes a constant volume pump.
Claim 10
Dependent Claim
30 words
Apparatus according to claim 8 wherein said pump is arranged so that said sub-stream of fluid will pass through said pump after said sub-stream has passed said charge measuring means.
Claim 11
Dependent Claim
27 words
Apparatus according to claim 1 further comprising a charge neutralizing device for neutralizing pre-existing charges on said particles before said particles impact upon said triboelectric charging surface.
Claim 12
Dependent Claim
15 words
Apparatus according to claim 10 wherein said charge neutralizing device comprises an alternating current ionizer.
Claim 13
Dependent Claim
86 words
Apparatus according to claim 1 wherein said sub-stream producing means comprises: a conduit member formed of electrically-conductive material and having walls defining a conduit through which said fluid can flow; an electrode at least part of which is disposed within said conduit; an insulator disposed between said conduit member and said electrode, thereby electrically insulating said electrode from said conduit member; current measuring means electrically connected to said electrode; and potential maintaining means for maintaining said conduit member and said electrode at substantially the same potential.
Claim 14
Dependent Claim
44 words
Apparatus according to claim 12 wherein said potential maintaining means comprises a connection between said conduit member and ground and a connection between said current measuring means and ground such that current from said electrode will flow through said current measuring means to ground.
Claim 15
Dependent Claim
31 words
Apparatus according to claim 12 wherein said electrode has the form of an elongate rod extending part-way across said conduit in a direction substantially perpendicular to the flow of fluid therealong.
Claim 16
Dependent Claim
20 words
Apparatus according to claim 1 further comprising a filter for removing particles from said fluid before it passes said electrode.
Claim 17
Dependent Claim
45 words
Apparatus according to claim 1 further comprising a fluid receiving device which receives said fluid stream and cut-off means for preventing damage to said fluid receiving means wherever said charge measuring means indicates that the concentration of particles in said fluid exceeds a predetermined value.
Claim 18
Dependent Claim
35 words
Apparatus according to claim 16 wherein said fluid is a gas and wherein said fluid receiving device is an engine and said cut-off means comprises means for preventing said gas stream from reaching said engine.
Claim 19
Dependent Claim
16 words
Apparatus according to claim 16 wherein said cut-off means further comprises means for stopping said engine.
Claim 20
Dependent Claim
17 words
Apparatus according to claim 17 wherein said cut-off means further comprises means for providing a warning signal.
Claim 21
Independent Claim
76 words
A method for measuring the concentration of solid particles in a fluid stream which is susceptible to changes in velocity, said method comprising: producing a sub-stream of said fluid having a substantially constant and independent velocity; permitting said sub-stream to come into contact with a triboelectric charging surface, thereby effecting triboelectric charging of said solid particles in said sub-stream; and thereafter measuring the charge produced upon said particles by their impacts on said triboelectric charging surface.
Claim 22
Independent Claim
76 words
A method for measuring the concentration of solid particles in a fluid stream which is susceptible to changes in velocity, said method comprising: producing a sub-stream of said fluid having a substantially constant and independent velocity; permitting said sub-stream to come into contact with a triboelectric charging surface, thereby effecting triboelectric charging of said solid particles in said sub-stream; and thereafter measuring the charge produced upon said particles by their impacts on said triboelectric charging surface.
Claim 23
Dependent Claim
22 words
A method according to claim 20 further comprising neutralizing pre-existing charges on said particles before said sub-stream contacts said triboelectric charging surface.
Claim 24
Dependent Claim
31 words
A method according to claim 20 wherein said sub-stream of fluid is produced by means of a critical flow orifice located in said sub-stream and upstream of said triboelectric charging surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |