US3782888A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for heat treating with heat recuperation from material cooling and auxiliary heat during startup
Assignee: Allis Chalmers Corp
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Filing: 1972-10-04
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Granted: 1974-01-01
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Expires: 1992-10-04
Abstract
Abstract A method and apparatus is disclosed for heat treating mineral ore materials. The apparatus includes, in material series flow arrangement, a traveling grate preheater having at least one material drying zone and a preburn zone, a rotary kiln, and a cooler. The cooler has a first stage in which air becomes heated as the ore is cooled and this heated air is conducted through the kiln and preburning zones counter to material flow. The cooler has a second stage in which air is heated and thermal energy recuperated as the ore is further cooled and this second cooler stage air after being heated is conducted by a bypass conduit around the kiln and preburn zone to supply heat for drying the materials. An auxiliary air heater is associated with this bypass and according to the method disclosed, during start-up operation and before hot material arrives in the second stage of the cooler, the air heater is operated to heat the air conducted from the second stage of the cooler, for drying the material until hot material does arrive in the second stage of the cooler and thereafter heat transferred from the hot material to the air passing through the material in the second stage of the cooler, is utilized for drying the material. The disclosed apparatus operated according to the disclosed method, achieves improved fuel economy, more effective control of the drying or dehydrating operation, and such operation is achieved with a smaller kiln than heretofore required according to teachings of the prior art.
Inventors
- 👤 R Cnare
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:05
CPC Classifications
C; C22; C22B; C22B1/00; C22B1/14; C22B1/24; C22B1/2413; F; F27; F27B; F27B7/00; F27B7/20; F27B7/2016; F27B7/2066
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
352 words
In a material furnacing apparatus having structures defining at least a chamber for preconditioning material having a material inlet opening, a chamber for preburning material, a chamber for final heating material having a material inlet opening facing the preburning chamber, a first fuel burner in close proximity to a material discharge opening of the final heating chamber, a first stage cooling chamber and a second stage cooling chamber, with said chambers being connected together in series flow arrangement to define a material flow stream through said preconditioning chamber, the preburning chamber, the final heating chamber, the first stage cooling chamber, and the second stage cooling chamber, with the structures defining a passage for a counterflow of gas from said first stage cooling chamber through the final heating chamber to said preburning chamber, and: a. A first conduit means connected on the first end thereof to the second stage cooling chamber at a location operative to discharge therefrom air that has passed through material therein; b. A second conduit means connected on the first end thereof to the preburn chamber at a location on a side of the material stream opposite to the flow of gas through the passage, and a second end of the second conduit means being connected to the preconditioning chamber; c. A second end of the first conduit means connected to the second conduit means; d. Third conduit means connected to the preconditioning chamber at a location on a side of the material stream opposite the second end of the second conduit means and between the preburn chamber and the material inlet opening of the preconditioning chamber, for exhausting gas from the preconditioning chamber; and e. A heater connected to the first conduit means operative with a source of thermal energy independent of the first fuel burner, for heating air flowing through said first conduit during startup operations when hot material from the final heating chamber has not yet passed into said second stage cooling chamber and any other period of operation when more heat is required than is being recuperated from material in the second stage cooling chamber.
Claim 2
Dependent Claim
352 words
In a material furnacing apparatus having structures defining at least a chamber for preconditioning material having a material inlet opening, a chamber for preburning material, a chamber for final heating material having a material inlet opening facing the preburning chamber, a first fuel burner in close proximity to a material discharge opening of the final heating chamber, a first stage cooling chamber and a second stage cooling chamber, with said chambers being connected together in series flow arrangement to define a material flow stream through said preconditioning chamber, the preburning chamber, the final heating chamber, the first stage cooling chamber, and the second stage cooling chamber, with the structures defining a passage for a counterflow of gas from said first stage cooling chamber through the final heating chamber to said preburning chamber, and: a. A first conduit means connected on the first end thereof to the second stage cooling chamber at a location operative to discharge therefrom air that has passed through material therein; b. A second conduit means connected on the first end thereof to the preburn chamber at a location on a side of the material stream opposite to the flow of gas through the passage, and a second end of the second conduit means being connected to the preconditioning chamber; c. A second end of the first conduit means connected to the second conduit means; d. Third conduit means connected to the preconditioning chamber at a location on a side of the material stream opposite the second end of the second conduit means and between the preburn chamber and the material inlet opening of the preconditioning chamber, for exhausting gas from the preconditioning chamber; and e. A heater connected to the first conduit means operative with a source of thermal energy independent of the first fuel burner, for heating air flowing through said first conduit during startup operations when hot material from the final heating chamber has not yet passed into said second stage cooling chamber and any other period of operation when more heat is required than is being recuperated from material in the second stage cooling chamber.
Claim 3
Dependent Claim
47 words
A material furnacing apparatus according to claim 1 having a fourth conduit means connected on the first end to the preburn chamber on the side of the material stream facing the flow of gas through the passage and on a second end thereof to the second conduit.
Claim 4
Dependent Claim
52 words
A material furnacing apparatus according to claim 2 having auxiliary heating means projecting into the preburn chamber on the side of the material stream facing the flow of gas through the passage and between the material inlet opening of the final heating chamber and the first end of the fourth conduit means.
Claim 5
Dependent Claim
35 words
A material furnacing apparatus according to claim 2 having a fifth conduit means connecting the second conduit means at a location downstream of both the first and fourth conduit means, to the third conduit means.
Claim 6
Dependent Claim
341 words
In a material furnacing apparatus having a traveling grate enclosed by structures defining at least a first stage drying chamber, second stage drying chamber and a chamber for preburning material, a rotary kiln for final heating material having a material inlet opening facing the preburning chamber, a firSt fuel burner in close proximity to a material discharge opening of the kiln, a first stage cooling chamber, and a second stage cooling chamber, with said chambers and kiln being connected together in series flow arrangement to define a material flow stream through said first and second drying chambers, the preburning chamber, the kiln, the first stage cooling chamber, and the second stage cooling chamber, and with the structures defining a passage for a counterflow of gas from the first stage cooling chamber through the kiln to said preburning chamber, and; a. A first conduit means connected on a first end thereof to the second stage cooling chamber at a location operative to discharge therefrom air that has passed through the material therein; b. A second conduit means connected on a first end thereof to the preburn chamber at a location beneath the grate, and a second end of the second conduit means being connected above the grate to the second stage drying chamber; c. A second end of the first conduit means having a first branch connected to the second conduit means and the second branch connected beneath the grate to the first stage drying chamber; d. Third conduit means connected above the grate to the first stage drying chamber for exhausting gas from the first stage drying chamber; and e. A heater connected to the first conduit means operative with a source of thermal energy independent of the first fuel burner, for heating air flowing through said first conduit during startup operations when hot material from the kiln has not yet passed into the second stage cooling chamber and any other period of operation when more heat is required than is being recuperated from material in the second stage cooling chamber.
Claim 7
Dependent Claim
341 words
In a material furnacing apparatus having a traveling grate enclosed by structures defining at least a first stage drying chamber, second stage drying chamber and a chamber for preburning material, a rotary kiln for final heating material having a material inlet opening facing the preburning chamber, a firSt fuel burner in close proximity to a material discharge opening of the kiln, a first stage cooling chamber, and a second stage cooling chamber, with said chambers and kiln being connected together in series flow arrangement to define a material flow stream through said first and second drying chambers, the preburning chamber, the kiln, the first stage cooling chamber, and the second stage cooling chamber, and with the structures defining a passage for a counterflow of gas from the first stage cooling chamber through the kiln to said preburning chamber, and; a. A first conduit means connected on a first end thereof to the second stage cooling chamber at a location operative to discharge therefrom air that has passed through the material therein; b. A second conduit means connected on a first end thereof to the preburn chamber at a location beneath the grate, and a second end of the second conduit means being connected above the grate to the second stage drying chamber; c. A second end of the first conduit means having a first branch connected to the second conduit means and the second branch connected beneath the grate to the first stage drying chamber; d. Third conduit means connected above the grate to the first stage drying chamber for exhausting gas from the first stage drying chamber; and e. A heater connected to the first conduit means operative with a source of thermal energy independent of the first fuel burner, for heating air flowing through said first conduit during startup operations when hot material from the kiln has not yet passed into the second stage cooling chamber and any other period of operation when more heat is required than is being recuperated from material in the second stage cooling chamber.
Claim 8
Dependent Claim
39 words
A material furnacing apparatus according to claim 5 having a fourth conduit means connected on a first end to the preburn chamber above the grate and on the second end thereof to the second branch of the first conduit.
Claim 9
Dependent Claim
27 words
A material furnacing apparatus according to claim 6 having the second end of said fourth conduit having a connection to the first branch of the first conduit.
Claim 10
Dependent Claim
181 words
In a method of heat treating material including steps in which such material is fed successively through preconditioning, preburning, final heat treating, first stage cooling and second stage cooling zones; and air from the first stage cooling zone is heated from a source of thermal energy to provide heated gases which are directed through the final heat treating zone, preburning and preconditioning zones, the steps comprising: a. Passing air through the second stage cooling zone and bypassing this air around the final heat treating and preburning zones to pass through material in the preconditioning zone; b. Heating and air from the second stage cooling zone with a source of thermal energy independent of the source of thermal energy utilized in the step of heating air from the first stage cooling zone, at least until material heated in the final heat treating zone arrives in the second stage cooling zone; and c. Thereafter transferring heat from the material in the second stage cooling zone to the air passing therethrough and utilizing this heated air to heat treat material in the preconditioning zone.
Claim 11
Dependent Claim
181 words
In a method of heat treating material including steps in which such material is fed successively through preconditioning, preburning, final heat treating, first stage cooling and second stage cooling zones; and air from the first stage cooling zone is heated from a source of thermal energy to provide heated gases which are directed through the final heat treating zone, preburning and preconditioning zones, the steps comprising: a. Passing air through the second stage cooling zone and bypassing this air around the final heat treating and preburning zones to pass through material in the preconditioning zone; b. Heating and air from the second stage cooling zone with a source of thermal energy independent of the source of thermal energy utilized in the step of heating air from the first stage cooling zone, at least until material heated in the final heat treating zone arrives in the second stage cooling zone; and c. Thereafter transferring heat from the material in the second stage cooling zone to the air passing therethrough and utilizing this heated air to heat treat material in the preconditioning zone.
Claim 12
Dependent Claim
77 words
A method according to claim 8 and in the step of heating the air from the second stage cooling zone with a source of thermal energy independent of the source of thermal energy utilized in the step of heating air from the first stage cooling zone, burning fuel and mixing air therewith to heat the air that passes to and through material in the preconditioning zone to a temperature in the range of about 500* to 750*F.
Claim 13
Dependent Claim
113 words
A method according to claim 8 with the added steps of withdrawing from the preburning zone a portion of the heated gases that have been directed through the final heating zone, to bypass the said withdrawn portion away from material in the preburning zone, and mixing the said withdRawn portion with the air passing from the second stage cooling zone to the preconditioning zone, to add heat thereto and provide a first mix for heat treating material in the preconditioning zone at least when excess heat is available in the gases from the final heating zone and until material heated in the final heat treating zone arrives in the second stage cooling zone.
Claim 14
Dependent Claim
111 words
A method according to claim 10 in which the preconditioning zone heat treatment is divided into a first stage and a second stage, dividing into a first branch and a second branch the heated gases withdrawn from the preburning chamber and away from the material therein, mixing the said first branch of gases with gases from the final heating zone that have passed through material in the preburning zone to provide a second mix, and passing this second mix through material in the second preconditioning stage, and mixing the second branch of gases with the air from the second stage cooling zone for passing through material in the first preconditioning stage.
Claim 15
Dependent Claim
71 words
A method according to claim 11 in which the air from the second stage cooling zone is divided into a first branch and a second branch, mixing the first branch of air with the gases from the final heating zone that have passed through material in the preburning zone, and mixing the second branch of air with the portion of heated gases withdrawn from the preburning zone away from material therein.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |