GB2108155A - Process and device for gaseous atmosphere separation in plants for heat treatment under pressure - Google Patents
Process and device for gaseous atmosphere separation in plants for heat treatment under pressure Download PDFInfo
- Publication number
- GB2108155A GB2108155A GB08127560A GB8127560A GB2108155A GB 2108155 A GB2108155 A GB 2108155A GB 08127560 A GB08127560 A GB 08127560A GB 8127560 A GB8127560 A GB 8127560A GB 2108155 A GB2108155 A GB 2108155A
- Authority
- GB
- United Kingdom
- Prior art keywords
- metal
- gas flow
- heat treatment
- bath
- fact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000010438 heat treatment Methods 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000000926 separation method Methods 0.000 title claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 claims abstract description 49
- 239000002184 metal Substances 0.000 claims abstract description 49
- 238000000576 coating method Methods 0.000 claims abstract description 26
- 239000011248 coating agent Substances 0.000 claims abstract description 21
- 239000007789 gas Substances 0.000 claims description 39
- 239000000463 material Substances 0.000 claims description 5
- 230000001681 protective effect Effects 0.000 claims description 5
- 238000009833 condensation Methods 0.000 claims description 3
- 230000005494 condensation Effects 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 2
- 239000001257 hydrogen Substances 0.000 claims description 2
- 229910052739 hydrogen Inorganic materials 0.000 claims description 2
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 238000011084 recovery Methods 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims 4
- 229910052757 nitrogen Inorganic materials 0.000 claims 2
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 229910000611 Zinc aluminium Inorganic materials 0.000 description 2
- HXFVOUUOTHJFPX-UHFFFAOYSA-N alumane;zinc Chemical compound [AlH3].[Zn] HXFVOUUOTHJFPX-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 238000003618 dip coating Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000001883 metal evaporation Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Coating With Molten Metal (AREA)
Abstract
A process for the separation of gaseous atmospheres in heat treatment plants under atmosphere, especially in dip metal coating plants; this process being characterized by the fact that the gaseous atmosphere separation is performed near to the coating metal bath 14 and to the heat treatment furnace 12 by injecting a gas flow into an enclosed space 10 connecting the heat treatment furnace 12 to the metal bath 14 in such a way that a part of this gas flow through vestibule 20 is conveyed to the furnace 12 and the other part through vestibule 22 sweeps the bath 14 neighbouring zone, collects coating metal vapors, is then exhausted and treated. The metal vapours are condensed by heat exchangers 28, 30 as the gas is exhausted. <IMAGE>
Description
SPECIFICATION
Process and device for gaseous atmosphere separation in plants for heat treatment under pressure
This invention refers to a process and a device for the separation of gaseous atmospheres in heat treatment plants under atmosphere, especially in dip metal coating plants. It is well known that, in a great number of heat treatment plants under atmosphere before dip coating, the metal forming the coating is heated to temperatures that are much higher than the melting temperature.
This heating results in an intense metal evaporation. The vapors spreaded in various parts of the treatment plant condense and form a deposit on the coldest parts. These metal deposits may give rise to difficulties when they appear on systems or pipings conveying protective gas. The metal particles are thus in suspension and may come into contact with the material to be metal coated, for example a strip thus preventing an efficient metal coating. These difficulties appear especially in strip annealing lines before coating with zinc, zinc-aluminum alloy or any other alloy. The purpose of the invention is to provide a process preventing any transfer of vapors containing coating metal to parts of the plant where a heat treatment is performed.
For this purpose the invention concerns a process for the separation of gaseous atmospheres in heat treatment plants under atmosphere, especially in dip metal coating plants. This process is characterized by the fact that the gaseous atmosphere separation is performed near to the coating metal bath surface and to the heat treatment furnace. According to this process a gas flow is injected into an enclosed space connecting the heat treatment furnace to the metal coating bath in such a way that a part of this gas flow is conveyed to the heat treatment furnace and the other part sweeps the bath neighboring zone, collects coating metal vapors, is then exhausted and treated.According to another aspect of this process the part of the gas flow containing metal vapors is discharged and treated so as to achieve a metal vapor condensation and subsequently a recovery of the metal evaporated from the bath, the protective gas contained in the gas flow being burnt at the outlet of the treatment envelope.
The invention also concerns a device that will bring the above described process into operation. This device is characterized by the fact that it is provided with : an enclosed space through which the material to be metal coated is conveyed between the heat treatment furnace and the metal bath; means of injecting the gas flow into the aforesaid enclosed space; means of dividing the gas flow into two parts, these means being located in the enclosed space and so designed that the division of the flow into two parts, to the heat treatment furnace and to the metal coating bath, be in accordance with the requirements of the treatment and metal coating process; means of exhausting and then treating the gases containing coating metal vapors.
According to the invention the means of dividing the gas flow consist of a system with two vestibules arranged in the enclosed space, the gas flow being injected between these two vestibules the cross sections of passage of which are so adjusted as to divide the gas flow into two parts. According to another aspect of this invention the means of exhausting the gases containing coating metal vapors comprise: an insulated discharge pipe; two or more parallel mounted liquid cooled exchangers which condense the metal vapors; a protective gas exhaust pipe provided with a pressure control valve; a gas burning system consisting of a torch for instance.
According to another aspect of the invention the flowrate at the pressure control valve of the burnt gas exhaust pipe is so adjusted and regulated as to maintain a positive pressure above the bath surface.
Other characteristics and advantages of the present invention will now be described with reference to the attached drawing the single figure of which is a schematic view of a device according to the invention located on an annealing plant before dip coating in a metal bath, for example a liquid zinc bath or zinc aluminum alloy bath or any other alloy. As indicated hereabove the gaseous atmospheres are separated near to the molten metal bath surface 14 and to the heat treatment furnace 1 2. This separation is achieved by the injection 18 of a gas flow into an enclosed space 10 arranged on the travel of the material to be coated (in this example a strip 16) between the furnace 12 and the metal bath 14.
According to the invention the gas flow injected in 18 is previously heated so as not to cool the strip; this heating being performed in accordance with the requirements of the treatment and metal coating process used. According to this example of design the gas flow separation device consists of two vestibules 20-22 between which the gas flow 18 is injected. The cross sections of passage of the two vestibules 20-22 are so adjusted that the gas flow is divided into two distinct streams, one (arrow f1) is conveyed to the bath, the other (arrow f2) is conveyed to the heat treatment furnace 12. The separation of the gas flows on each side of the device is performed in such a way that it meets the overall requirements of the treatment and metal coating process.
Each vestibule can be of the flap or roller type or of the flap and roller type as shown on the drawing. It may include means making a quick opening possible in order to ensure the passage of defective strips or of inlet material. Locking systems can be provided in addition in order to reduce the gas flowrates when the plant is stopped.
The device according to the invention also includes a system located in the chute 42 above the metal bath for the exhaust and the treatment of protective gas containing coating metal vapors.
The whole device being referred to under number 24 consists of an insulated discharge pipe 26 connected with the chute 42, of two parallel mounted exchangers 28-30 (water cooled for example) for metal vapor condensation, of an exhaust pipe 32 provided with a pressure control valve 34. This device is completed by a gas burning device including a torch 36 for example.
The exchangers 28-30 are provided each with a downstream shut-off valve 40, resp. 40' and an upstream shut-off valve 38, resp. 38' which make possible to remove and clean the exchanger tubes on which the coating metal vapors condense. The cleaning occurs while the other exchanger ensures the operation of the equipment.
Thanks to the control valve 34 located on the gas exhaust pipe 32 it is possible to maintain a positive pressure above the metal bath surface and to prevent any ambient air penetration likely to cause an explosion. The usual operating parameters of a plant according to the invention are given hereunder by way of non limitative example:
Gas flow: Nature: N2, N2 + H2 mixture in any proportion
containing 0 to 75% of hydrogen Temperature: 20 to 450 C Pressure: in the separation device: 0.6 mb to 33 mb Flowrate: 30 to 200 Nm3/hr through each vestibule 20-22
Metal bath: Nature: Zinc, Zn + Al alloy in any required proportion Temperature: 450 to 650 C.
It is well understood that this invention is not limited to the herein described and illustrated example of design but includes all the variants thereof. In the same way the application chosen to illustrate the invention is only one simple and non limitative example.
Claims (7)
1. A process for the separation of gaseous atmospheres in heat treatment plants under atmosphere, especially in dip metal coating plants; this process being characterized by the fact that the gaseous atmosphere separation is performed near to the coating metal bath and to the heat treatment furnace by injecting a gas flow into an enclosed space connecting the heat treatment furnace to the metal bath in such a way that a part of this gas flow is conveyed to the furnace and the other part sweeps the bath neighboring zone, collects coating metal vapors, is then exhausted and treated.
2. A process according to claim 1 characterized by the fact that the part of the gas flow containing metal vapors is exhausted and treated so as to achieve a metal vapor condensation and subsequently a recovery of the metal evaporated from the bath, the protective gas contained in the gas flow being burnt at the outlet.
3. A process according to claim 1 or 2 characterized by the fact that the gas flow is heated prior to its injection into the enclosed space so as not to cool the strip, this heating depending on the requirements of the treatment and metal coating process used.
4. A process according to claim 3 characterized by the fact that the temperature of the gas flow ranges from 20 to 450 C.
5. A process according to any one of the preceding claims characterized by the fact that the gas flow consists of nitrogen or of a nitrogen + hydrogen mixture.
6. A device for the utilization of the process according to any one of claims 1 to 5 characterized by the fact that it is provided with: an enclosed space (10) through which the material to be metal coated is conveyed between the heat treatment furnace (12) and the metal bath (14); means (18) of injecting the gaseous flow into the aforesaid enclosed space: means of dividing this gas flow into two parts, these means being located in the enclosed space and so designed that the flow division into two parts to the heat treatment furnace and to the metal bath corresponds to the requirements of the treatment and metal coating process; means (24) of exhausting and treating gases containing coating metal vapors.
7. A device according to claim 6 characterized by the fact that the gas flow separation device consists of two vestibules (20-22) located in the enclosed space (10); the gas flow being injected between these 2 vestibules the cross sections of passage of which are adjusted in order
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08127560A GB2108155B (en) | 1981-09-11 | 1981-09-11 | Process and device for gaseous atmosphere separation in plants for heat treatment under pressure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08127560A GB2108155B (en) | 1981-09-11 | 1981-09-11 | Process and device for gaseous atmosphere separation in plants for heat treatment under pressure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2108155A true GB2108155A (en) | 1983-05-11 |
| GB2108155B GB2108155B (en) | 1985-09-18 |
Family
ID=10524464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08127560A Expired GB2108155B (en) | 1981-09-11 | 1981-09-11 | Process and device for gaseous atmosphere separation in plants for heat treatment under pressure |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2108155B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2212518A (en) * | 1987-11-14 | 1989-07-26 | Leybold Ag | Apparatus for coating continuous webs |
| WO2005001152A1 (en) * | 2003-06-27 | 2005-01-06 | Sms Demag Aktiengesellschaft | Method for hot dip coating a metal bar and method for hot dip coating |
| WO2007003357A1 (en) * | 2005-07-01 | 2007-01-11 | Sms Demag Ag | Method and device for hot-dip coating a metal strip |
| US7807726B2 (en) | 2005-03-11 | 2010-10-05 | 3M Innovative Properties Company | Recovery of fluorinated surfactants from a basic anion exchange resin having quaternary ammonium groups |
-
1981
- 1981-09-11 GB GB08127560A patent/GB2108155B/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2212518A (en) * | 1987-11-14 | 1989-07-26 | Leybold Ag | Apparatus for coating continuous webs |
| GB2212518B (en) * | 1987-11-14 | 1992-02-12 | Leybold Ag | Apparatus for coating continuous webs |
| WO2005001152A1 (en) * | 2003-06-27 | 2005-01-06 | Sms Demag Aktiengesellschaft | Method for hot dip coating a metal bar and method for hot dip coating |
| US7807726B2 (en) | 2005-03-11 | 2010-10-05 | 3M Innovative Properties Company | Recovery of fluorinated surfactants from a basic anion exchange resin having quaternary ammonium groups |
| WO2007003357A1 (en) * | 2005-07-01 | 2007-01-11 | Sms Demag Ag | Method and device for hot-dip coating a metal strip |
| US20080145569A1 (en) * | 2005-07-01 | 2008-06-19 | Holger Behrens | Method and Device For Hot-Dip Coating a Metal Strip |
| KR100941626B1 (en) * | 2005-07-01 | 2010-02-11 | 에스엠에스 지마크 악티엔게젤샤프트 | Method and device for hot-dip coating a metal strip |
| CN101384746B (en) * | 2005-07-01 | 2011-07-06 | Sms西马格股份公司 | Method and device for hot-dip coating a metal strip |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2108155B (en) | 1985-09-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19920911 |