CN105621510B - A kind of vortex electromagnetic induction evaporator - Google Patents
A kind of vortex electromagnetic induction evaporator Download PDFInfo
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- CN105621510B CN105621510B CN201410620963.1A CN201410620963A CN105621510B CN 105621510 B CN105621510 B CN 105621510B CN 201410620963 A CN201410620963 A CN 201410620963A CN 105621510 B CN105621510 B CN 105621510B
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- evaporating kettle
- electromagnetic induction
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Abstract
The invention discloses a kind of vortex electromagnetic induction evaporators, including evaporating kettle, the top of evaporating kettle is installed by steam pipe, the middle part of steam pipe is installed by condenser, the lower part of evaporating kettle is installed by conical shell, the lower part of conical shell is installed by residue outlet, the external side installation vortex electromagnetic induction heater of evaporating kettle.The present invention generates high current using vortex electromagnetic induction heater, high current to by coiling circlewise or other shapes of first coil, thus the strong flux of polarity instantaneous variation is generated in first coil, the heating objects such as metal are placed in coil, flux will penetrate through entire heating object, in the inside of the heating object direction opposite with heated current, corresponding very big eddy current will be generated.
Description
Technical field
The present invention relates to a kind of vortex electromagnetic induction evaporators.
Background technique
High slat-containing wastewater refers to the quality point of TDS containing total dissolved solidss (Total Dissolved Solid) and organic matter
Number is more than or equal to 3.5% waste water, including sanitary wastewater with high salt and industrial wastewater with high salt.It is mainly derived from and directly utilizes seawater
Industrial production, sanitary sewage and food processing factory, pharmaceutical factory, the acquisition processing of chemical plant and oil and natural gas etc..These are useless
In addition to containing organic contamination beyond the region of objective existence in water, also contain a large amount of inorganic salts, such as Cl-, SO42-, Na+, Ca2+ plasma.These are high
Salt, high organic wastewater will certainly use aqueous bio, Drinking Water and industrial and agricultural production if unprocessed direct emission
Water generates high risks.The common feature of such density wastewater is: cannot simply use biochemical treatment, and materializing strategy process is more multiple
Miscellaneous, processing cost is higher, is the generally acknowledged highly difficult processing waste water of sewage treatment industry.
About the processing technique of high slat-containing wastewater, decades are had studied both at home and abroad, the method master generallyd use at present
It include: bioanalysis, SBR Process and evaporative desalination method etc..Evaporation is one of modern chemical industry unit operation, i.e., with the side of heating
Method vaporizes the partial solvent in solution and removes, and to improve the concentration of solution, or is precipitated and creates conditions for solute.Evaporative desalination
Method is the method for being removed the inorganic salts in waste liquid in the way of evaporation by condensing crystallizing system.
For currently known sewage treatment vapo(u)rization system due to cost height, running cost is high, and maintenance cost is high, and operating process is difficult
Many enterprises can not select.Electromagnetic heater is at present to metal material heating efficiency highest, fastest, low-loss and energy-saving environmental protection
The induction heating equipment of type is a kind of advanced heating method, because only that exporting in sample combustion Shi Caiyou high frequency power, combustion
After the completion of burning, high-frequency induction stops.Electromagnetic heater after actuation, does not need heating preheating time, can be at any time to sample
It is analyzed.Electromagnetic heater has very excellent combustibility, and carbon sulphur conversion ratio is above tube furnace, and carbon is believed that almost
Up to 100%, sulphur is according to the relevant information, up to 99% or more.Existing evaporator uses common fossil fuel as sewage
Vapo(u)rization system heat source is handled, does so that the thermal efficiency is low, and preheating time is long, environmental pollution is big.
Summary of the invention
The technical problem to be solved by the present invention is to overcome the defects of the prior art, provide a kind of vortex electromagnetic induction evaporation
Device.
In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:
The top of a kind of vortex electromagnetic induction evaporator of the present invention, including evaporating kettle, evaporating kettle is installed by steam pipe, steam pipe
Middle part condenser is installed, conical shell is installed in the lower part of evaporating kettle, and residue outlet is installed in the lower part of conical shell, evaporating kettle it is outer
Portion side installation vortex electromagnetic induction heater, electromagnetic induction generator can the replacement of free fast assembling-disassembling, vortex electromagnetic induction
First coil is installed, first coil is located at conical shell periphery, and conical shell is metal shell, and conical shell can be on heater
The strong flux of instantaneous variation is generated in first coil, under the action of strong flux, temperature is increased, so that the sewage flowed through be fired
Evaporation is burnt, residue outlet is installed in conical shell lower part, and sewage pipe is installed in the middle part side of evaporating kettle, and sewage pipe is located on the inside of evaporating kettle
One end spray head is installed, using a variety of spray modes such as top direct injection, side spray formula, scraper-type, bottom spraying type, rotary to sewage
Carry out spray burning evaporation.High current is generated using vortex electromagnetic induction heater, high current is to circlewise or other by coiling
Thus the first coil of shape generates the strong flux of polarity instantaneous variation in first coil, the heating objects such as metal is put
It sets in coil, flux will penetrate through entire heating object, in the inside of the heating object direction opposite with heated current,
Corresponding very big eddy current will be generated.Since there is resistance in heating object, so many Joule heats can be generated,
The temperature of object itself is risen rapidly, achievees the purpose that heat all metal materials, then sprays sewage to heating board
On carry out burning evaporation.The efficiency of energy utilization for substantially increasing vortex electromagnetic induction evaporator, avoids air pollution.
Further, electric machine support is installed in the evaporating kettle side, installs motor on electric machine support, on the output shaft of motor
Connecting rod is installed, the side of evaporating kettle opens up open-work, and connecting rod passes through open-work, installs stir plate in connecting rod, stir plate is located at
Inside evaporating kettle.
Further, filter screen bracket is installed in the side of the residue outlet, installs guide rod on filter screen bracket, pacifies on guide rod
Guide plate is filled, opens up pilot hole on guide plate vertically, guide plate is cooperated by pilot hole and guide rod, the side installation of guide plate
Strainer is installed in fixed ring, fixed ring inside, and strainer is located at below residue outlet, the side mounting plate of fixed ring, in fixed plate
Screw hole is opened up vertically, bolt is installed in screw hole, and fixing sleeve is installed in the side of filter screen bracket, and screw rod end and the fixing sleeve of bolt are matched
It closes.
Heating efficiency of the present invention is up to 90% or more, the 20%-30% of energy consumption only old-fashioned electron tube high frequency, standby mode
Under hardly electricity consumption, and can 24 continuous throughout the twenty-four hour24s production.Moment, which proposes heat, degree only needs 3-4 seconds from 0 degree to 1000, heat condition
It is continued at 1000 degree or more.The present invention has the control function of constant current and firm power, greatly optimizes metal
Heating process is realized and efficiently, is quickly heated.The present invention is to the adaptable of sample simultaneously, and especially to tube furnace, electric arc furnaces is difficult
In the special material of burning, such as stainless steel, Gao Ge, potassium steel, electrothermal alloy, intermediate alloy, pure metal (Ni, Co, Cu etc.),
Ferrosilicon, ferrochrome in ferroalloy, ore, clinker, sinter, oil shale, graphite, tungsten carbide, rare earth material and various nonmetallic
Raw material etc. have preferable combustion efficiency.
The present invention has the advantages that
One, of the invention, the decontamination of high temperature flash evapn is carried out to sewage using the fever of vortex electricity, which is one kind between steaming
A kind of technology between hair and burning, the evaporation depolluting processes flames of anger generate, and not only environmentally friendly but also safety, electromagnetic heater are starting
Afterwards, heating preheating time is not needed, after the completion of burning, high-frequency induction stops immediately, and heating efficiency is high, evaporation rate is fast, low consumption
Energy conservation and environmental protection, ton cost of water treatment are low.
Two, spraying and sprinkling evaporation burning of the present invention is synchronous carries out, and simple for structure compact, performance is stablized, easy to operate, manufacturing cost
Cheap, the present invention has 95% removal rate to the water of heavy metal pollution, the high concentrations complexity waste water such as wastewater from chemical industry pharmacy waste water,
Good market prospect.
Detailed description of the invention
Attached drawing is used to provide further understanding of the present invention, and constitutes part of specification, with reality of the invention
It applies example to be used to explain the present invention together, not be construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the structural diagram of the present invention；
Fig. 2 is I enlarged structure schematic diagram of Fig. 1；
Fig. 3 is II enlarged structure schematic diagram of Fig. 1.
Mark component: 1 condenser, 2 steam pipe, 3 evaporating kettle, 4 sewage pipe, 5 spray head, 6 conical shell, 7 first coil 8
It is vortexed 9 residue outlet of electromagnetic induction heater, 10 stir plate, 11 connecting rod, 12 open-work, 13 motor, 14 electric machine support, 15 strainer branch
22 guide plate of frame 16 guide rod, 17 fixed ring, 18 strainer, 19 bolt, 20 fixing sleeve, 21 pilot hole, 23 screw hole 24 is fixed
Plate.
Specific embodiment
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, it should be understood that preferred reality described herein
Apply example only for the purpose of illustrating and explaining the present invention and is not intended to limit the present invention.
As shown in Figure 1, a kind of vortex electromagnetic induction evaporator, as shown in Figure 1, Figure 2 and Figure 3, including evaporating kettle 3, evaporation
Steam pipe 2 is installed on the top of kettle 3, and condenser 1 is installed at the middle part of steam pipe 2, and conical shell 6, taper are installed in the lower part of evaporating kettle 3
Residue outlet 9 is installed in the lower part of shell 6, and the external side installation vortex electromagnetic induction heater 8 of evaporating kettle 3 is vortexed electromagnetic induction
First coil 7 is installed, first coil 7 is located at 6 periphery of conical shell, and conical shell 6 is metal shell, conical shell on heater 8
Residue outlet 9 is installed in 6 lower part of body, and sewage pipe 4 is installed in the middle part side of evaporating kettle 3, and sewage pipe 4 is located at one end of 3 inside of evaporating kettle
Spray head 5 is installed.The present invention generates high current using vortex electromagnetic induction heater 8, and high current is to circlewise or other by coiling
Thus the first coil 7 of shape generates the strong flux of polarity instantaneous variation, by heating objects such as metals in first coil 7
It is placed in coil, flux will penetrate through entire heating object, in the inside of the heating object side opposite with heated current
To corresponding very big eddy current will be generated.Since there is resistance in heating object, so many joules can be generated
Heat rises rapidly the temperature of object itself, achievees the purpose that heat all metal materials, then sprays sewage to fever
Burning evaporation is carried out on plate.A variety of spray sides such as top direct injection, side spray formula, scraper-type, bottom spraying type, rotary can be used in spray
Formula carries out spray burning evaporation to sewage.Conical shell 6 of the invention is metal shell, and conical shell 6 can be in first coil 7
Temperature increases under the action of generating the strong flux of instantaneous variation, so that the sewage flowed through is carried out burning evaporation.
The present invention is light-weight, small in size, installation is simple, connects three phase mains, the water inlet, water outlet of 380V, a few minutes
It is achievable.The present invention is especially safe, and output voltage is lower than 36V, exempts high pressure Danger Electric shock risk.Heating efficiency of the present invention is up to 90%
More than, the 20%-30% of energy consumption only old-fashioned electron tube high frequency, hardly electricity consumption under standby mode, and can 24 hours continuous works
It produces.Present invention land occupation is minimum, and easy to operate, a few minutes can learn.Inductor of the present invention can the replacement of free fast assembling-disassembling, surpass
Quickly heating greatly reduces the oxidation deformation of workpiece.The present invention has the control function of constant current and firm power, greatly
Ground optimizes the heating process of metal, realizes that efficiently, quickly heating, the superior function of product are not fully exerted.Automatic control of the present invention
Heating time, heating power, soaking time, heat preservation power and cooling time is adjusted in type；Substantially increase the matter of heating product
The repeatability of amount and heating simplifies the operating technology of worker.The present invention replaces steam-heated newest environment-friendly products, and the flames of anger is raw
Produce safer trust.
Due to the sewage poor dispersion that spray head 5 sprays, make to be vortexed electromagnetic induction evaporator to the evaporation efficiency of sewage not
Height, to solve the above-mentioned problems, the present invention in the following ways: 3 side of evaporating kettle electric machine support 14, electric machine support are installed
Motor 13 is installed on 14, connecting rod 11 is installed on the output shaft of motor 13, the side of evaporating kettle 3 opens up open-work 12, connecting rod 11
Stir plate 10 is installed on open-work 12, connecting rod 11, stir plate 10 is located inside evaporating kettle 3.Motor 13 of the invention can be with
Stir plate 10 is driven to rotate, stir plate 10 can break up sewage when spray head 5 sprays sewage, keep sewage fully dispersed, significantly
Electromagnetic induction evaporator is improved to the evaporation efficiency of sewage.
There is solid particle in the waste residue being discharged due to residue outlet 9, the waste residue with solid particle can be blocked by direct emission
Sewer pipe, to solve the above-mentioned problems, the present invention in the following ways: filter screen bracket 15 is installed in the side of the residue outlet 9,
Guide rod 16 is installed on filter screen bracket 15, guide plate 22 is installed on guide rod 16, pilot hole 21 is opened up vertically on guide plate 22, leads
Cooperated to plate 22 by pilot hole 21 and guide rod 16, fixed ring 17 is installed in the side of guide plate 22, installs on the inside of fixed ring 17
Strainer 18, strainer 18 are located at below residue outlet 9, the side mounting plate 24 of fixed ring 17, open up spiral shell vertically in fixed plate 24
Hole 23, screw hole 23 is interior to install bolt 19, and fixing sleeve 20, the screw rod end of bolt 19 and fixing sleeve are installed in the side of filter screen bracket 15
20 cooperations.The solid particulate filters in waste residue can be discharged in residue outlet 9 by strainer 18 of the invention, avoided with solid particle
Waste residue blocks sewer pipe by direct emission.The height of strainer 18 of the invention can be adjusted by bolt 19, thus by strainer
18 are fixed on proper height, and sewage is avoided to splash.
Finally, it should be noted that the foregoing is only a preferred embodiment of the present invention, it is not intended to restrict the invention,
Although the present invention is described in detail referring to the foregoing embodiments, for those skilled in the art, still may be used
To modify the technical solutions described in the foregoing embodiments or equivalent replacement of some of the technical features.
All within the spirits and principles of the present invention, any modification, equivalent replacement, improvement and so on should be included in of the invention
Within protection scope.
Claims (2)
1. a kind of vortex electromagnetic induction evaporator, it is characterised in that: including evaporating kettle (3), steam is installed on the top of evaporating kettle (3)
It manages (2), condenser (1) is installed at the middle part of steam pipe (2), and conical shell (6) are installed in the lower part of evaporating kettle (3), conical shell (6)
Lower part install residue outlet (9), evaporating kettle (3) external side installation vortex electromagnetic induction heater (8), vortex electromagnetic induction
First coil (7) are installed on heater (8), first coil (7) is located at conical shell (6) periphery, and conical shell (6) is metal-back
Sewage pipe (4) are installed in the middle part side of body, evaporating kettle (3), and sewage pipe (4) is located at the installation of one end on the inside of evaporating kettle (3) spray head
(5), filter screen bracket (15) are installed in the side of the residue outlet (9), install guide rod (16) on filter screen bracket (15), guide rod
(16) guide plate (22) are installed on, are opened up vertically pilot hole (21) on guide plate (22), guide plate (22) passes through pilot hole (21)
Cooperate with guide rod (16), fixed ring (17) are installed in the side of guide plate (22), install strainer (18) on the inside of fixed ring (17), filter
Net (18) is located at below residue outlet (9), and the side mounting plate (24) of fixed ring (17), fixed plate opens up spiral shell on (24) vertically
Hole (23), screw hole (23) is interior to install bolt (19), and fixing sleeve (20) are installed in the side of filter screen bracket (15), the screw rod of bolt (19)
End and fixing sleeve (20) cooperate.
2. vortex electromagnetic induction evaporator according to claim 1, it is characterised in that: evaporating kettle (3) the side installation
Electric machine support (14) installs motor (13) on electric machine support (14), installs connecting rod (11) on the output shaft of motor (13), evaporation
The side of kettle (3) opens up open-work (12), and connecting rod (11) passes through open-work (12), installs stir plate (10) in connecting rod (11), stirs
It is internal that movable plate (10) is located at evaporating kettle (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410620963.1A CN105621510B (en) | 2014-11-05 | 2014-11-05 | A kind of vortex electromagnetic induction evaporator |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410620963.1A CN105621510B (en) | 2014-11-05 | 2014-11-05 | A kind of vortex electromagnetic induction evaporator |
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| CN105621510A CN105621510A (en) | 2016-06-01 |
| CN105621510B true CN105621510B (en) | 2019-04-23 |
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| CN201410620963.1A Active CN105621510B (en) | 2014-11-05 | 2014-11-05 | A kind of vortex electromagnetic induction evaporator |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105944396A (en) * | 2016-06-28 | 2016-09-21 | 钮德明 | Electromagnetic heat pipe heating vacuum evaporator |
| CN106943761A (en) * | 2017-04-07 | 2017-07-14 | 宝鸡宝冶钛镍制造有限责任公司 | Multiinjector low-power heating type vapor seperator |
| CN107224754A (en) * | 2017-07-03 | 2017-10-03 | 重庆骏成机械配件有限公司 | Cleaning fluid regenerating unit |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2464713Y (en) * | 2001-02-22 | 2001-12-12 | 杨得山 | Energy-saving sewage treating device |
| CN2647834Y (en) * | 2003-06-05 | 2004-10-13 | 柳云珍 | Energy saving water distiller |
| CN2687106Y (en) * | 2004-04-13 | 2005-03-23 | 戎志远 | Electromagnetic Water distilling device |
| CN201565167U (en) * | 2009-12-13 | 2010-09-01 | 上海凡清环境工程有限公司 | Movable filter plate positioning or guiding device |
| CN201978512U (en) * | 2010-12-28 | 2011-09-21 | 许广胜 | Electromagnetic heating type rotary evaporator |
| CN202576015U (en) * | 2012-05-04 | 2012-12-05 | 刘方旭 | Seawater electromagnetic-heating, desalting and gas-collecting device |
| CN202643354U (en) * | 2012-05-15 | 2013-01-02 | 厦门锐思达机电科技有限公司 | Device utilizing clean energy to carry out sea water desalination |
| CN204281364U (en) * | 2014-11-05 | 2015-04-22 | 江苏元捷环境科技有限公司 | A kind of eddy current electromagnetic induction vaporizer |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09122635A (en) * | 1995-10-30 | 1997-05-13 | Seta Giken:Kk | Apparatus for removing impurity in water |
-
2014
- 2014-11-05 CN CN201410620963.1A patent/CN105621510B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2464713Y (en) * | 2001-02-22 | 2001-12-12 | 杨得山 | Energy-saving sewage treating device |
| CN2647834Y (en) * | 2003-06-05 | 2004-10-13 | 柳云珍 | Energy saving water distiller |
| CN2687106Y (en) * | 2004-04-13 | 2005-03-23 | 戎志远 | Electromagnetic Water distilling device |
| CN201565167U (en) * | 2009-12-13 | 2010-09-01 | 上海凡清环境工程有限公司 | Movable filter plate positioning or guiding device |
| CN201978512U (en) * | 2010-12-28 | 2011-09-21 | 许广胜 | Electromagnetic heating type rotary evaporator |
| CN202576015U (en) * | 2012-05-04 | 2012-12-05 | 刘方旭 | Seawater electromagnetic-heating, desalting and gas-collecting device |
| CN202643354U (en) * | 2012-05-15 | 2013-01-02 | 厦门锐思达机电科技有限公司 | Device utilizing clean energy to carry out sea water desalination |
| CN204281364U (en) * | 2014-11-05 | 2015-04-22 | 江苏元捷环境科技有限公司 | A kind of eddy current electromagnetic induction vaporizer |
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| CN105621510A (en) | 2016-06-01 |
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Effective date of registration: 20201230 Address after: 232000: 50m to the east of Hehuai road and north of Beizhan Road, Shannan new area, Huainan City, Anhui Province Patentee after: Huainan Baibang Pneumatic Technology Co.,Ltd. Address before: 214000 No.2, Huahui Road, industrial cluster, Gaocheng Town, Yixing City, Wuxi City, Jiangsu Province Patentee before: JIANGSU YUANJIE ENVIRONMENT TECHNOLOGY Co.,Ltd. |