US1551724A

US1551724A - Art of electrical precipitation of suspended material from gases

Info

Publication number: US1551724A
Application number: US564974A
Authority: US
Inventors: Anderson Evald
Original assignee: International Precipitation Co
Current assignee: International Precipitation Co
Priority date: 1922-05-31
Filing date: 1922-05-31
Publication date: 1925-09-01
Anticipated expiration: 1942-09-01

Description

Sept. 1,- 1925. v

\ I E. ANDERSON ARTIOFELEOTRICAL PRECIPITATION 0F SUSPENDED MATERIAL FROM GASES Filed May 31, 1922 INVENTOR. E'vald flnclerson.

ATTORNEY.

Patented Sept. 1, 1925.

UNIT-ED snares .uvALn ANDERSON, or ALHAMBR cALironNIA', ASSIGNOR mo mmam nu. ram

CIPITATION COMPANY, or nos ANGELES, cAr..Iro1mI-A;A conronArIon o cA I- romu 4 Arm or ELECTRICAL rnEcrn rA'rmN or-susrmmnn am. r301; eA'sns.

Application mm Kay a1, 1922. Serial No. 504,074..

To all whom it may concern:

Be it known that I4, EVALD ANnnnsoia a citizen of United States, residing at A hambra, county of ,Los Angeles, State,of* California, have invented a new and useful Improvement in the Art of- ElectricalPre action, and the main object of the invention is'to provide for such separation in a con- J tinuous manner so that the-electrical precipitating operation proceeds continuously and does not have to be interrupted for cleaning operations.

In the operation of electrical preci itation apparatus the gases carrying suspe ed material arepassed between discharge and col.- lecting electrodes which are, maintained at high electrical potential difference, in such manner that the suspended material car-- ried by the gases isdeposited or collected'to a greater or less extent on such electrodes; and in the operation of such apparatus it has heretofore generally been necessary to shut down the apparatus from timeto time so as to enable the material collected-on the electrodes to'be removed therefrom. Such shutting down of the'apparatus has -gener-' ally included the shutting off of; the gas streamby means of dampers or otherwlse, so as to preventmaterial dislodged from the electrodes in. the cleaning operation. from being carried forward with'the gas stream and from being discharged at the outlet nuisance or loss 0 or stack of the a paratus, resulting 'in a cleaning operation as heretofore conducted, therefore, involves. acessation of the normal operation of the .treater, resultin indecreased capacity of the treater'an in considerabl'e'expense due to the oversight and control required in connection with such cleaning operations. I 1

By means of my-invention hereinafter described, the gases are cleaned byj'passing .them through a series of electrical precipitation zones, each precipitating zone includ- 'ing a set of electrodes, and electrodes inthe successive sets being subjected to cleaning valuable material. The

and supported operation for removing deposited material therefrom .at different times so that at all times the major part of the, precipitatlng 1 an time, the number of sections being suffic'ient to always provide for effective pre-- cipitation by the operation of those sections which are not beingcleaned.

The accompanying drawings i llu'strate embodiments of my invention and referr' means is in operation and the cleaning optheretoz; Fig. 1 is a longitudinal section 0 one form of such apparatus. Fig. 2 is .a

vertical section on line2 -2 of Fig. 1.

3 is a longitudinal section .of another form of such, apparatus. 2 Fig. ,4 is asection on line 4-4 in Fig. 3. Fig. 5 is a diagram of a modified form of; electrical circuit control.

In Figs. 1 and 2 my invention is shown as applied to an electrical precipitator of the s'oj-called plate and wire type comprisin collecting electrodes formed as plates an 7 dischargeelectrodes formed as wires, chains or other flexible members, all arranged in a flue or chamber 1 through which the gases are passed, the said electrodes being arranged in a series of sections for units indi-' cated at 2, it being understood, however,

that any desired number of units or sections may be used provided the number 'is sufiiciently great to give the desiredouniformity of operation. In general, at least five sections are desirable. Eachfsection 2 includes a set of collecting electrode plates or screens 3 and a set of high tension discharge electrodes- 4 arranged in alternation with and opposite to the respective plates. The collecting electrodes-3 may be suspended from by supporting consisting. of beams indicated at 6. The discharge electrodes 4 may be supported by frame means 7 which is mounted on insulators 9. Any other suitable construction of electrodes and of support may, however, 'be

used; for example, the collecting electrodes 3 may be formedas plates or screens on as a series of chains, wires, or other flexible members spaced sufliciently close to produce approximately the efl ect of a continuous con- I'BJIIB 11168113 ducting surface; and the discharge elec ting off the draft or gas flow on the pre-- cipitator, it is desirable to provide for shaking, agitating or rapping the electrodes by means operating outside of the precipitating flue. For this purpose, the collecting electrode frames'above described may be provided with anvils 10 projecting through the wall of the flue, for example, through the roof thereof and similarly the discharge electrode frames may be provided with anvils 11 projecting through the roof of the flue, suitable insulation indicated at 8 being provided where these anvils from the discharge electrodes pass through the roof. If it is desired to clean the precipitator by manual operation, the operator will pass over the flue, striking the anvils l0 and 11 for each section so as to jar the collecting and discharge electrodes in such section and will pass from section to section so as to operate upon the-electrodes of the several sections successively. In this operation most of the material dislodged from the electrodes of any one section will fall into the receiving means or hoppers indicated at 5, at the bottom of the flue. In this connection, it may be stated that the material which has been precipitated and which is dislodged on shaking is generally conglom: erated into larger masses than the original dust and fume content in the gases thus minimizing the tendency for the material to pass along with the gas stream. In general, however, more or less of such dislodged material particularly the finer particles thereof'will be carried forward with the gas stream and Will be collected in succeeding sections of the precipitator. It may also be stated that in electrical precipitating apparatus of'this nature, including a series of sections operating successively on the gas stream, the major portion of the suspended material is caught in the first few sections.

and the last sections of the precipitator only serve to perform a final clean-up and receive but little material so that in cleaning such last sections, the material which may pass therefrom and fail to be caught in a succeeding section is a relatively .small amount.

I prefer to provide for automatic operation of the cleaning means so that the expense of manual control or operation of the apparatus is reduced to a" minimum. For this purpose an operating shaft 13 may be provided extending above the flue 1 and aoove the respective sections of the precipitatorv above described, said shaft carrying cams 14: adapted to operate upon trip hammers 15 which are mounted on a suitable pivotal support 16 and are adapted to strike anvil means 10 on the collecting electrode and anvil means 11 on the discharge electrode.

A control shaft 18 is also provided carrying a series of cams 19 which normally engage projections 20 on the respective trip hammers 15 to hold the same out of engagement with the operating cams 14. When the notch or depressed portion of any cam 19 comes opposite the projection 20 for the corresponding trip hammer, such trip hammer is lowered into position for operation thereof by the cam means 14; the severalcams 19 being so positioned as to bring the series of trip hammers 15 successively into operation and show that the cleaning r operation progresses along the treater from section'to section and is repeated indefinitely in a cyclic manner. In case it is desired to cut off the current during the cleaning operation, this may be effected by switch means controlled, for example, by the control shaft 18. Thus, the cams 19 on said shaft may operate switch levers 22 for making connections between contacts 23 and 24 connected respectively to an electrical supply circuit-25 and (by wire 26) to the high tension discharge electrodes of the section corresponding to said cam, there being a switch 22 for each section or unit of the circuit during the operation of the cleaning means therein.

Suitable circuit connections are made for supplying the electrical precipitator with the unidirectional current of high potential difference, such connections including, for

example, a rectifier of suitable type connect-' ply transformer, Fig. 5 showing diagram,

matically circuit connections suitable for this purpose, 26 indicating the supply lines leading to the discharge electrodes for the respective sections, 28 indicating a suitable rectifier such as a mechanical rectifier, or a valve rectifier such as a kenotron, said rectifier being connected to the secondary of a high tension transformer, which is provided with aground connection indicated at 29. The primary winding 30 of each of said transformers may be connected at one Side treater so that each section is shut off in the to an alternating current supply line indicated at 32 and at the other side to one'of a series of contacts 33 adapted to be engaged by contact means 34 on'the control shaft 18 aforesaid, said contacts 34 being so positioned and arranged as to successively in-.

terrupt the primary or energizing circuits for the respective transformers and to shut oil the supply of electrical energy to eachconstruct-ion extending transversely of the flue 37 and formed, for example, of vertical Wires or chains, spaced sufliciently close together to produce approximately the effect of a substantially continuous surface, and the high tension discharge electrodes 38'being formed as wires, chains, or 'rods of a small cross section spaced sufiicient-ly far apart to facilitate electrical discharge therefrom and suspended fromframes supported 'on insulators 39. In this case the gas to be cleaned passes successively through the discharge electrodes and collecting electrodes and provision is made for successive cleaning of the sets of discharge and receiving electrodes; for example, by means of hammer devices 40 and 41 res ectively for the discharge electrodes and the collecting electrodes, said hammer devices beingcarried by levers 42 mounted on pivot or shaft 43 andoperated by cam means 44 on a shaft 45 rotated in any suitable manner. In the rotation of said'shaft the levers, 42 are successively operated ,so as to raise the corresponding hammer devices 'which are allowed to fall suddenly into contact with the respective electrodes, In the operation of this form of my invention the gas stream passes successively through the series of discharge and collecting electrodes and is subjected tot-he action of electrical field maintained between said electrodes in such manner as to cause electrical precipitation of suspended material onthe electrodes, such suspended material being removed from the electrodes by successive operation of the cleaning means on the respectlve electrodes,

only one or a limited number of electrodes being cleaned at any one time, and the material dislodged therefrom falling into the collecting means 48 at the bottoni'of the flue 37 or being collected on succeedingelectrodes'a's the case maybe.

My invention may be carried out n such manner as to provide for clean ng ofthe recipitator sections while the potential diference is maintained between the electrodes thereof, the cleaning means shown in Figs.

3 and 4 being suitable for the purpose, su'itable insulation, indicated at 46, being provided for the hammer devices for the high tension electrodes.

What I claim is: 1. The method of removing suspended material from gases which consists in subjecting a gas stream to the action of a series of electrical fields, each of said fields be in produced by a separate set of discharge an collecting electrodes, and cleaning electrodes of each set indpendently of the other sets without'interruption of the gas stream.

2. The method of removing suspended so I material from gases which consists in subjecting a gas stream to the action ofa series of electrical fields, each of said fields bein produced by ,a separate set of discharge an collecting electrodes, and cleaning both the discharge and collecting electrodes of each set independently of the other sets without interruption of the gas stream.

3. The method of removing sus ended material from gases which consists in subjecting the gas stream to the action of, a series of electrical fields, each of said fields being maintained between discharge and collecting electrodes, and subjecting the said electrodes for the respective electrical fieldsto cleaning action successively without interruption of the gas stream, the electrical connection to the electrodes of each of the electrical fields being interrupted during the cleaning operation thereon;

4. An apparatus for electrical precipitation of suspended material fromgases comprising a series of precipitatin sections eachconiprising a separate set 0 opposin electrodes, and means for maintaining sai opposing electrodes at high potential difference and cleaning means adapted to operate on electrodes of each set independent-1y of the other sets of the electrical precipit-ator, while the gas flow is maintained through such. sections, the number of sections being sufiicient to enable effective precipitation of suspended material from the gases by the operation of the electrical precipitator as awhole during each of such cleaning operations.

5. An apparatus for electrical precipitation of suspended material irom gases comprising, a series of precipitating sections each comprising opposing electrodes, and means for maintaining said opposing elec trodes at high potential difierence, cleaning means adapted to operate successively on the successive sections of the electrical recipit-ator, while-the gas flow is maintained through such sections, the number of sec tions being suflicient to enable efi'ective precipitation of suspended .material from the gases by the o eration of the electrical precipitatoras a w ole during each of such cleaning operations, and. means for interrupting the supply of electric current to each of such sections during the cleaning thereof. g

6. The method of removing suspended material from gases which consists in cansing such gases to flow horizontally through a series of electric fields maintained between vertically extending electrodes and subjecting the said electrodes for the respective electrical fields to cleaning action successively without interruption of the gas stream.

7. The method as set forth in claim 6 and comprising in addition interrupting the 15 In testimony whereof I have hereunto subscribed my name this 22nd day of May, 20

EVALD ANDERSON.