Patent US4419184A successfully refreshed from Google Patents.
US4419184A
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Method for control of chemicals during gas treatment of suspensions
Assignee: Metso Fiber Karlstad AB
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Filing: 1981-07-20
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Granted: 1983-12-06
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Expires: 2001-07-20
Abstract
Abstract A method of treating medium consistency paper pulp or the like with a treament gas, such as oxygen, is provided to achieve uniform treatment results. The treatment gas is added to the pulp in finely distributed small bubbles, and the density of the suspension is measured at at least one moment, or the average density is measured during at least one time period. The temperature and the pressure of the suspension corresponding to the density measurements are determined, and the rest gas content of the substance is calculated at the actual moments or time periods based upon the measurements in the preceding steps. The gas consumption is then calculated as the difference between the quantity of gas added, and the residual gas quantity, or between two residual gas quantities. The gas addition step is controlled based upon the calculated consumption to obtain substantially uniform treatment results.
Inventors
- 👤 Ake Backlund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:56
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1068; D21C9/1026; D21C9/1052; G; G01; G01N; G01N33/00; G01N33/34; G01N33/343; G01N9/00; G01N9/36
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
193 words
A method of treating a pulp suspension with a treatment gas comprising the steps of: (a) adding a quantity of treatment gas to the pulp suspension in the form of finely distributed small bubbles the gas selected from the group consisting essentially of oxygen and oxygen containing gas; (b) after step (a), determining the density of the suspension containing the treatment gas at at least one moment; (c) simultaneously measuring the temperature and pressure of the suspension containing the treatment gas corresponding to the density determined during step (b); (d) calculating the residual gas content of the suspension at the at least one moment at which the density is determined, the calculation utilizing the information determined in steps (b) and (c); (e) calculating the gas consumption as the difference between the quantity of gas added in step (a) and the residual gas quantity calculated according to step (d); (f) controlling the quantity of gas added in step (a) based upon the consumption calculation in step (e) to obtain a desired resultant treatment of the suspension; and wherein steps (b) through (f) are practiced while maintaining the suspension at a substantially contant superatmospheric pressure.
Claim 2
Independent Claim
193 words
A method of treating a pulp suspension with a treatment gas comprising the steps of: (a) adding a quantity of treatment gas to the pulp suspension in the form of finely distributed small bubbles the gas selected from the group consisting essentially of oxygen and oxygen containing gas; (b) after step (a), determining the density of the suspension containing the treatment gas at at least one moment; (c) simultaneously measuring the temperature and pressure of the suspension containing the treatment gas corresponding to the density determined during step (b); (d) calculating the residual gas content of the suspension at the at least one moment at which the density is determined, the calculation utilizing the information determined in steps (b) and (c); (e) calculating the gas consumption as the difference between the quantity of gas added in step (a) and the residual gas quantity calculated according to step (d); (f) controlling the quantity of gas added in step (a) based upon the consumption calculation in step (e) to obtain a desired resultant treatment of the suspension; and wherein steps (b) through (f) are practiced while maintaining the suspension at a substantially contant superatmospheric pressure.
Claim 3
Dependent Claim
26 words
A method as recited in claim 1 wherein step (b) is practiced so that the density of the suspension is determined at a plurality of moments.
Claim 4
Dependent Claim
42 words
A method as recited in claim 2 wherein steps (a) through (f) are practiced continuously with the suspension moving in a substantially constant volume flow, and with the treatment gas being added and mixed into the suspension in a substantially even flow.
Claim 5
Dependent Claim
53 words
A method as recited in claim 3 wherein the suspension is passed through a substantially vertical treatment vessel maintained at substantially constant superatmospheric pressure and at a temperature above 80° C.; and wherein step (b) is practiced by measuring the static pressure difference between two or more levels in the vertical treatment vessel.
Claim 6
Dependent Claim
42 words
A method as recited in claim 3 wherein the suspension moves through a substantially vertical treatment vessel maintained at substantially constant superatmospheric pressure and at a temperature above 80° C.; and wherein step (b) is accomplished by utilizing a device utilizing radioactivity.
Claim 7
Independent Claim
186 words
A method of treating a pulp suspension with a treatment gas comprising the steps of: (a) adding a quantity of treatment gas to the pulp suspension in the form of finely distributed small bubbles the gas selected from the group consisting essentially of oxygen and oxygen containing gas; (b) after step (a), determining the average density of the suspension containing the treatment gas during at least one time period; (c) simultaneously measuring the temperature and pressure of the suspension containing the treatment gas corresponding to the density measurement according to step (b); (d) calculating the residual gas content of the suspension during the time period during which the average density is determined, utilizing the information determined according to steps (b) and (c); (e) calculating the gas consumption as the difference between two residual gas quantities calculating according to step (d); (f) controlling the quantity of gas added in step (a) based upon the consumption calculated according to step (e) to obtain a desired resultant treatment of the suspension; and wherein steps (b) through (f) are practiced while maintaining the suspension at a substantially contant superatmospheric pressure.
Claim 8
Independent Claim
186 words
A method of treating a pulp suspension with a treatment gas comprising the steps of: (a) adding a quantity of treatment gas to the pulp suspension in the form of finely distributed small bubbles the gas selected from the group consisting essentially of oxygen and oxygen containing gas; (b) after step (a), determining the average density of the suspension containing the treatment gas during at least one time period; (c) simultaneously measuring the temperature and pressure of the suspension containing the treatment gas corresponding to the density measurement according to step (b); (d) calculating the residual gas content of the suspension during the time period during which the average density is determined, utilizing the information determined according to steps (b) and (c); (e) calculating the gas consumption as the difference between two residual gas quantities calculating according to step (d); (f) controlling the quantity of gas added in step (a) based upon the consumption calculated according to step (e) to obtain a desired resultant treatment of the suspension; and wherein steps (b) through (f) are practiced while maintaining the suspension at a substantially contant superatmospheric pressure.
Claim 9
Independent Claim
22 words
A method as recited in claims 1 or 6 wherein steps (b) through (f) are practiced at a temperature above 80° C.
Claim 10
Dependent Claim
28 words
A method as recited in claim 2 or 3 wherein the suspension comprises a suspension of comminuted cellulosic fibrous material having a consistency of about 5 to 15%.
Claim 11
Dependent Claim
41 words
A method as recited in claim 8 wherein steps (a) through (f) are performed continuously with the suspension moving in a substantially constant volume flow and with the treatment gas added and mixed into the suspension in a substantially even flow.
Claim 12
Dependent Claim
95 words
A method as recited in claim 8 wherein steps (a) through (f) are performed continuously with the suspension moving in a substantially constant volume flow, and wherein the treatment gas is added and mixed into the suspension in a substantially even flow; and wherein the suspension moves through a substantially vertical vessel maintained a substantially constant superatmospheric pressure, and at a temperature above 80° C.; and wherein step (b) is practiced so that the density values obtained are adjusted to take into account possible variations in the flow velocity of the suspension through the vessel.
Claim 13
Dependent Claim
74 words
A method as recited in claim 8 wherein steps (a) through (f) are practiced continuously with the suspension moving in a substantially constant volume flow; and wherein the suspension is passed through a substantially vertical vessel maintained as substantially constant superatmospheric pressure and at a temperature above 80° C.; and comprising the further step of passing the suspension into and through the vessel under the influence of the pressure from a preceding continuous digestor.
Claim 14
Dependent Claim
23 words
A method as recited in claim 8 wherein steps (b) through (f) are practiced at a temperature of about 95° to 120° C.
Claim 15
Independent Claim
20 words
A method as recited in claims 2 or 6 wherein step (b) is practiced by utilizing a device utilizing radioactivity.
Claim 16
Dependent Claim
42 words
A method as recited in claim 6 wherein steps (a) through (f) are practiced continuously with the suspension moving in a substantially constant volume flow, and with the treatment gas being added and mixed into the suspension in a substantially even flow.
Claim 17
Dependent Claim
53 words
A method as recited in claim 14 wherein the suspension is passed through a substantially vertical treatment vessel maintained at substantially constant superatmospheric pressure and at a temperature above 80° C.; and wherein step (b) is practiced by measuring the static pressure difference between two or more levels in the vertical treatment vessel.
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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) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |