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US4125018A
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Method of and means for accurately measuring the calorific value of combustible gases
Assignee: Instromet Inc
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Filing: 1977-04-27
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Granted: 1978-11-14
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Expires: 1997-04-27
Abstract
Abstract Method of and means for accurately measuring the calorific value of combustible gases wherein a mixture of combustible gas and combustion-supporting gas is burned in a pair of flames, the temperatures of the burned gases in both flames being monitored and the volume ratios of the combustion-supporting gas to the combustible gas fed to both burners being adjusted so as to maintain the average of said temperatures at substantially maximum; the volume ratio of said gases which produces said maximum average temperatures varying substantially directly with the calorific value of said combustible gas; the aforesaid calorific value being proportional to said volume ratio of said gases which maximizes said average temperatures; the flow rates of said gases being measured by a single flow sensing system, preferably, of the turbine flowmeter types, or the volumetric flow rate of said combustion-supporting gas being maintained at a constant value while the volumetric flow rate of said combustible gas is being measured; said calorific value measuring method and means being unaffected by ambient temperature and other varying environmental factors. In one embodiment, automatic calibration of the device is obtained by alternately feeding a standard gas and the unknown gas to the burners.
Inventors
- 👤 William H. Clingman, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:29
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/20; G01N25/22; G01N25/28; Y; Y10; Y10T; Y10T137/00; Y10T137/1842; Y10T137/1939; Y10T137/1963; Y10T137/1987; Y10T137/7722; Y10T137/7758; Y10T137/7759
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
331 words
Apparatus for measuring the calorific value of a combustible gas by mixing it with a combustion supporting gas and burning it, comprising: a pair of burners; a fuel supply system comprising: a main fuel supply line through which all of the combustible gas fed to both burners is passed; a fuel flow adjusting valve in said main fuel supply line; a first branch fuel supply line connected between said main fuel supply line at a point downstream of said flow adjusting valve and one of said burners; a second branch fuel supply line connected between said main fuel supply line at a point downstream of said flow adjusting valve and the other of said burners; capillary means in each of said branch fuel supply lines for establishing selected rates of fuel flow to said burners; and a turbine meter in one of said branch fuel supply lines; an air supply system comprising: a main air supply line through which all of the combustion supporting gas fed to both burners is passed; a pressure regulator in said main air supply line for establishing a substantially constant gas pressure in said line downstream thereof; a first branch air supply line connected between said main air supply line at a point downstream of said regulator and one of said burners; a second branch air supply line connected between said main air supply line at a point downstream of said regulator and the other of said burners; capillary means in each of said branch air supply lines for establishing selected rates of air flow to said burners; thermocouple means for sensing the temperatures of the burned gases in said burners; means responsive to said thermocouple means for adjusting said fuel flow adjusting valve to establish a fuel flow rate to maximize the average of said temperatures; means for measuring the revolutions of said turbine meter; and means for deriving a signal uniquely related to calorific value of the combustible gas from said measurement of revolutions.
Claim 2
Dependent Claim
331 words
Apparatus for measuring the calorific value of a combustible gas by mixing it with a combustion supporting gas and burning it, comprising: a pair of burners; a fuel supply system comprising: a main fuel supply line through which all of the combustible gas fed to both burners is passed; a fuel flow adjusting valve in said main fuel supply line; a first branch fuel supply line connected between said main fuel supply line at a point downstream of said flow adjusting valve and one of said burners; a second branch fuel supply line connected between said main fuel supply line at a point downstream of said flow adjusting valve and the other of said burners; capillary means in each of said branch fuel supply lines for establishing selected rates of fuel flow to said burners; and a turbine meter in one of said branch fuel supply lines; an air supply system comprising: a main air supply line through which all of the combustion supporting gas fed to both burners is passed; a pressure regulator in said main air supply line for establishing a substantially constant gas pressure in said line downstream thereof; a first branch air supply line connected between said main air supply line at a point downstream of said regulator and one of said burners; a second branch air supply line connected between said main air supply line at a point downstream of said regulator and the other of said burners; capillary means in each of said branch air supply lines for establishing selected rates of air flow to said burners; thermocouple means for sensing the temperatures of the burned gases in said burners; means responsive to said thermocouple means for adjusting said fuel flow adjusting valve to establish a fuel flow rate to maximize the average of said temperatures; means for measuring the revolutions of said turbine meter; and means for deriving a signal uniquely related to calorific value of the combustible gas from said measurement of revolutions.
Claim 3
Dependent Claim
77 words
Apparatus in accordance with claim 1 and further comprising: means for introducing a portion of the gas flowing through the main air supply line into the branch fuel supply line having the turbine meter therein at a point upstream of said turbine meter; means for periodically effecting said introduction; and means for comparing turbine meter revolutions when both gases are passing through said meter with turbine meter revolutions when only one gas is passing through said meter.
Claim 4
Dependent Claim
85 words
Apparatus in accordance with claim 2 in which said introducing means comprise: a third branch air supply line connected to said main air supply line downstream of said regulator; a capillary in said third branch air supply line for establishing air flow rate therethrough substantially less than the air flow rate through said first and second branch air supply lines; and a valve downstream of said capillary for alternately introducing air into said second branch fuel supply line upstream and downstream of said turbine meter.
Claim 5
Dependent Claim
63 words
Apparatus in accordance with claim 1 in which said signal deriving means includes means for introducing an adjustable calibration factor thereinto, and further comprising means for periodically introducing a combustible gas of known calorific properties into said main fuel supply line so that said calibration factor may be adjusted to produce a signal accurately reflective of the calorific value of said known gas.
Claim 6
Dependent Claim
44 words
Apparatus in accordance with claim 4 in which said means for introducing said known gas comprises a valve for alternately blocking flow of unknown gas and initiating flow of known gas and for discontinuing flow of known gas and resuming flow of unknown gas.
Claim 7
Dependent Claim
19 words
Apparatus in accordance with claim 1 in which the pressure regulator in said main air supply line is vented.
Claim 8
Dependent Claim
22 words
Apparatus in accordance with claim 3 and further comprising means for venting the air passed through said third branch air supply line.
Claim 9
Dependent Claim
25 words
Apparatus in accordance with claim 1 in which said turbine meter is located in the branch fuel supply line having the greater gas flow therethrough.
Claim 10
Independent Claim
226 words
A method of determining the calorific content of a combustible gas comprising: flowing said combustible gas to a pair of burners at selected rates for each burner; flowing a combustion-supporting gas to said pair of burners at selected rates for each burner; burning said combustible gas in said combustionsupporting gas in both burners; sensing the temperatures of the burned gases in both burners; altering the flow rate of combustible gas to said burners in a direction of maximize the average of said temperatures; at least part of said combustible gas being continually flowed through a turbine flowmeter upstream of said burners; measuring the rate of revolution said turbine flowmeter while combustible gas is flowing therethrough; dividing said measurement into a calibration factor representative of the flow rate of said combustion supporting gas to produce a signal which is a unique function of the calorific content of said combustible gas; periodically interrupting flow of said combustible gas and substituting therefor a flow of another combustible gas of known calorific content; adjusting said calibration factor during flow of said known gas to bring the signal produced by said division into correspondence with the calorific content of said gas; resuming flow of the combustible gas whose calorific content is being determined following said adjustment; and maintaining said calibration factor as adjusted upon said resumption until the next periodic interruption.
Claim 11
Independent Claim
226 words
A method of determining the calorific content of a combustible gas comprising: flowing said combustible gas to a pair of burners at selected rates for each burner; flowing a combustion-supporting gas to said pair of burners at selected rates for each burner; burning said combustible gas in said combustionsupporting gas in both burners; sensing the temperatures of the burned gases in both burners; altering the flow rate of combustible gas to said burners in a direction of maximize the average of said temperatures; at least part of said combustible gas being continually flowed through a turbine flowmeter upstream of said burners; measuring the rate of revolution said turbine flowmeter while combustible gas is flowing therethrough; dividing said measurement into a calibration factor representative of the flow rate of said combustion supporting gas to produce a signal which is a unique function of the calorific content of said combustible gas; periodically interrupting flow of said combustible gas and substituting therefor a flow of another combustible gas of known calorific content; adjusting said calibration factor during flow of said known gas to bring the signal produced by said division into correspondence with the calorific content of said gas; resuming flow of the combustible gas whose calorific content is being determined following said adjustment; and maintaining said calibration factor as adjusted upon said resumption until the next periodic interruption.
References Cited (Backward Citations)
US3393562A
Cited
US3777562A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-11-13 | 1982-05-15 | 1982-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-13 | 1986-05-15 | 1986-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-13 | 1990-05-15 | 1990-11-14 | $7700.00 | Window Closed / Lapsed |