US4793710A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring surface density of explosive and inert dust in stratified layers
Assignee: GOVERNMENT OF UNITED STATES INTERIOR, Secretary of
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Filing: 1987-06-09
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Granted: 1988-12-27
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Expires: 2007-06-09
Abstract
Abstract A method for determining the surface density of coal dust on top of rock dust or rock dust on top of coal dust is disclosed which comprises directing a light source at either a coal or rock dust layer overlaying a substratum of the other, detecting the amount of light reflected from the deposit, generating a signal from the reflected light which is converted into a normalized output (V), and calculating the surface density from the normalized output. The surface density S c of coal dust on top of rock dust is calculated according to the equation: S.sub.c =1/-a.sub.c ln(V) wherein a c is a constant for the coal dust particles, and the surface density S r of rock dust on top of coal dust is determined by the equation: ##EQU1## wherein a r is a constant based on the properties of the rock dust particles. An apparatus is also disclosed for carrying out the method of the present invention.
Inventors
- 👤 Michael J. Sapko
- 👤 Henry E. Perlee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:48
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4738; G01N15/00; G01N15/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
169 words
A method for determining the surface density of a coal dust layer on top of a rock dust substratum comprising the steps of: directing a light source onto a coal and rock dust deposit; detecting the amount of light reflected from the dust deposit; generating a signal proportional to the amount of light reflected from the dust deposit; determining a normalized output for the signal generated; calibrating the normalized output to correspond to range of values from a point at which a minimum amount of light is reflected from the dust deposit to a point at which a maximum amount of light is reflected from the dust deposit; and calculating the surface density of the coal dust Sc from the equation: S.sub.c =1/-a.sub.c ln(V) wherein V is the normalized output, and a c is a constant which is a function of the coal dust particle diameter D c and of the coal dust particle density l c , and which follows the relationship: ##EQU8## wherein k is a constant.
Claim 2
Independent Claim
169 words
A method for determining the surface density of a coal dust layer on top of a rock dust substratum comprising the steps of: directing a light source onto a coal and rock dust deposit; detecting the amount of light reflected from the dust deposit; generating a signal proportional to the amount of light reflected from the dust deposit; determining a normalized output for the signal generated; calibrating the normalized output to correspond to range of values from a point at which a minimum amount of light is reflected from the dust deposit to a point at which a maximum amount of light is reflected from the dust deposit; and calculating the surface density of the coal dust Sc from the equation: S.sub.c =1/-a.sub.c ln(V) wherein V is the normalized output, and a c is a constant which is a function of the coal dust particle diameter D c and of the coal dust particle density l c , and which follows the relationship: ##EQU8## wherein k is a constant.
Claim 3
Dependent Claim
32 words
A method according to claim 1 wherein surface density is measured in mg/cm 2 , particle diameter is measured in cm, and coal dust particle density is measured in mg/cm 3 .
Claim 4
Dependent Claim
140 words
A method according to claim 1 wherein the calibration step includes a determination of a saturation surface density of the coal dust, S c sat, which corresponds to the approximate point where the density of coal dust on top of a rock dust substratum reaches the level at which the minimum amount of light is reflected from the deposit, and a determination of normalized output from the signal generated by the light reflected from a dust deposit at its coal dust saturation surface density S c sat by the equation: Vsat,cd=e.sup.-a.sbsp.c.sup.S.sbsp.c.sup.sat wherein Vsat,cd is the normalized output at the coal dust saturation surface density and a c is a constant which is a function of the coal dust particle diameter D c and the coal dust density l c and which follows the relationship: ##EQU9## wherein k is a constant.
Claim 5
Dependent Claim
26 words
A method according to claim 3 wherein the saturation surface density of coal dust on top of a rock dust substratum is 7 mg/cm 2 .
Claim 6
Independent Claim
167 words
A method for determining the surface density of a rock dust layer on top of a coal dust substratum comprising the steps of: directing a light source onto a coal and rock dust deposit; detecting the amount of light reflected from the dust deposit; generating a signal proportional to the amount of light reflected from the dust deposit; determining a normalized output for the signal generated; calibrating the normalized output to correspond to a range of values from a point at which a minimum amount of light is reflected from the dust surface to a point at which a maximum amount of light is reflected from the dust deposit; and calculating the surface density of the rock dust, Sr, from the equation: ##EQU10## wherein V is the normalized output, and a r is a constant which is a function of the rock dust particle diameter D r and of the rock dust particle density l r and which follows the relationship: ##EQU11## wherein k is a constant
Claim 7
Independent Claim
167 words
A method for determining the surface density of a rock dust layer on top of a coal dust substratum comprising the steps of: directing a light source onto a coal and rock dust deposit; detecting the amount of light reflected from the dust deposit; generating a signal proportional to the amount of light reflected from the dust deposit; determining a normalized output for the signal generated; calibrating the normalized output to correspond to a range of values from a point at which a minimum amount of light is reflected from the dust surface to a point at which a maximum amount of light is reflected from the dust deposit; and calculating the surface density of the rock dust, Sr, from the equation: ##EQU10## wherein V is the normalized output, and a r is a constant which is a function of the rock dust particle diameter D r and of the rock dust particle density l r and which follows the relationship: ##EQU11## wherein k is a constant
Claim 8
Dependent Claim
32 words
A method according to claim 5 wherein surface density is measured in mg/cm 2 , particle diameter is measured in cm, and rock dust particle density is measured in mg/cm 3 .
Claim 9
Dependent Claim
141 words
A method according to claim 5 wherein the calibration step includes a determination of a saturation surface density of the rock dust, S r sat, which corresponds to the approximate point where the density of rock dust on top of a coal dust substratum reaches the level at which the maximum amount of light is reflected from the deposit, and a calculation of normalized output from the signal generated by the light reflected from a dust deposit at its rock dust saturation surface density S r sat by the equation: Vsat,rd=1-e.sup.a.sbsp.r.sup.S.sbsp.r.sup.sat wherein Vsat,rd is the normalized output at the rock dust saturation surface density, and a r is a constant which is a function of the rock dust particle diameter D r and the coal dust density l c , and which follows the relationship: ##EQU12## wherein k is a constant.
Claim 10
Dependent Claim
26 words
A method according to claim 7 wherein the saturation surface density of rock dust on top of a coal dust substratum is 14 mg/cm 2 .
Claim 11
Independent Claim
145 words
An apparatus for determining the surface density of a layer of coal dust on top of rock dust or a layer of rock dust on top of coal dust comprising: a light source for directing light onto a coal and rock dust deposit; a detecting means for detecting the amount of light reflected from the dust deposit; means for generating a signal proportional to the amount of light reflected from the dust deposit; means for determining a normalized output based on the signal generated; means for calibrating the normalized output to correspond to a range of values from a point at which a minimum amount of light is reflected from the dust surface to a point at which a maximum amount of light is reflected from the dust surface; and means for calculating the surface density of coal and rock dust from the normalized output.
Claim 12
Independent Claim
145 words
An apparatus for determining the surface density of a layer of coal dust on top of rock dust or a layer of rock dust on top of coal dust comprising: a light source for directing light onto a coal and rock dust deposit; a detecting means for detecting the amount of light reflected from the dust deposit; means for generating a signal proportional to the amount of light reflected from the dust deposit; means for determining a normalized output based on the signal generated; means for calibrating the normalized output to correspond to a range of values from a point at which a minimum amount of light is reflected from the dust surface to a point at which a maximum amount of light is reflected from the dust surface; and means for calculating the surface density of coal and rock dust from the normalized output.
Claim 13
Dependent Claim
81 words
An apparatus according to claim 9 wherein the surface density S c of coal dust on a top of rock dust is determined, and wherein said surface density is calculated according to the equation: S.sub.c =1/-a.sub.c ln(V) wherein V the normalized output, and a c is a constant which is a function of the coal dust particle diameter D c and of the coal dust particle density l c , and which follows the relationship: ##EQU13## wherein k is a constant.
Claim 14
Dependent Claim
79 words
An apparatus according to claim 9 wherein the surface density S r of rock dust on top of coal dust is determined, and wherein said surface density is calculated according to the equation: ##EQU14## wherein V is the normalized output, and a r is a constant which is a function of the rock dust particle diameter D r and of the rock dust particle density l r , and which follows the relationship: ##EQU15## wherein k is a constant.
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) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |