US 1204907 A
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Description (OCR text may contain errors)
prircrnn s'rATEs rA OFFICE.
WALTER AUGUST SCHMIDT, OF LOS ANGELES, CALIFORNIA, ASSIGNOR T0 INTER- NATIONAL PRECIPITATION COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORA- TION' OF CALIFORNIA.
Specification of Letters Patent.
Patented Nov. 14, 1916.
Application filed June 17, 1915. Serial No. 34,583.
To all whom it may concern:
Be it known that I, WALTER AUGUST SCHMIDT, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have in vented a new and useful Means for Pro+ ducing Discharge of Electricity into Gases, of which the following is a specification.
lhis invention relates to apparatus for subjecting gases to the action of an electric discharge, and particularly to apparatus in which the discharge is used for separation of suspended particles from the gases.
The main object of my invention is to provide for control of the electric discharge, so that the amount of discharge may be adapted to the particular requirements of any special case, and in this connection an important object of the invention is to provide for control of the discharge for the purpose of increasing the discharge from a discharge electrode into the surrounding gas when this electrode is discharging with the .so-called silent or glow or brush discharge.
My invention is especially applicable in connection with the type of electric sepa- 4 rating apparatus comprising a pipe or pipes with discharge electrodes extending therein, the gas being passed through such pipes and being subjected to discharge from such electrodes. In such apparatus, the discharge electrodes are generally Wires hung axially in said pipes, and with such a construction the size of the pipe that can be used is limited by the fact that it is not practicable to obtain the proper conditions of discharge and of electrostatic field strength with pipes over a certain size.
In treating large volumes of gas it is desirable to use pipes of large diameter, and an important object of my invention is to enable pipes of any required diameter to be used, and to provide for control of the electric field conditions so that any desired intensity of discharge and of electrostatic field may be obtained With any sized pipe.
I have found that by subdividing the discharge electrode and suitably spacing the members thereof from one another and from the wall of the opposing or pipe electrode, the intensity of the electric field adjacent to each electrode may be modified by the influence of the adjacent electrodes so that by properly choosing the arrangement of the charged bodies, conductors, or discharge electrodes, the discharge may be brought under control, and the discharge may be either raised or lowered as desired, for any given operating conditions.
The principle of action on which this invent on 18 based was disclosed in my former application Ser. No. 639,016, filed July 17, 111, of which this application is, in part, a continuation.
The accompanying drawings illustrate embodiments of my invention, and referring thereto:
Figure l is a vertical section of a vertical pipetreater. Fig. 2 is a section on line 22 in Fig. 1. Fig. 3 is an elevation of a modilied construction of the discharge electrode. Fig. at 15 a perspective view of discharge and oppos ng electrode elements, and Fig. 5 is a sectional View of such elements, illustrating the principles of the invention, as disclosed many former application aforesaid.
According to my invention, the discharge electrode consists of a plurality of electrode members, formed preferably as fine Wires, 1, say 1/20 inch in diameter, hung from a support 2, mounted on suitable insulatingmeans 3; said Wires being arranged in polygonal, or annular order. The complete electrode formed by this set of Wires or members 1 is surrounded by an electrode Wall, formed for example as the Wall of a pipe or cylindrical chamber l, through which the gas is to be passed for treatment. This pipe or chan1- b er may have lower and upper gas connections of conduits 5 and 6 for conducting the gas to and from the treater. The Wires 1 may be held taut and properly spaced by a frame 7 at the lower end of the set of Wires,
said frame being supported by an insulator 8, or, as shown in Fig. 8, the frame '5' may be hung on the Wires themselves.
The discharge electrode may be connected by wire 10 to suitable means for applylng high electrical potential thereto, for example, to the secondary Winding of a stepup transformer 11, the primary Winding thereof being connected to an alternating current supply circuit. A rectifier 12 may be included in the circuit of the device if unidirectional current is required, the rectifier being provided with a ground connection 13 and the pipe electrode 4 being grounded as at 1a.
In the operation of this invention, a high potential difference, alternating or direct according to the requirements of the case, is maintained between the electrodes 1 and 4, by means of the circuit connections described, and an electrical discharge is thereby produced from the electrode 1 into the gas in the chamber or pipe electrode 4. In many cases, particularly where the apparatus is being used for separation of suspended particles from gases, it is desirable that the discharge be substantially unidirectional and suflicient to properly charge the particles suspended in the gas, without being so excessive as to waste an undue amount of energy; and it is also desirable that an electrostatic field of the proper strength be maintained between the electrodes, so as to insure migration of the particles toward the electrodes.
In case of a large plant, requiring treatment of great quantities of gas, it is desirable to make the gas-receiving channels or passages as large as possible in cross section to avoid undue multiplication of such passages, and in the case of a pipe treater this involves the use of comparatively large pipes. With such large pipes it is impracticable to, secure proper conditions of discharge and of electrostatic field strength by the use of a single discharge conductor arranged axially in each pipe. To produce an electrostatic field of properintensity in such a large pipe requires the central conductor to be charged to an unduly high potential, resulting in excessive ionization and consequent waste of electrical energy. I have found, however, that by properly subdlv ding the discharge conductor 1nto a plurality of conductor members, and arranging such conductor members in an annular or polygo nal system, that the proper proportions of discharging action and electrostatic field action may be produced, and may be relatively varied within the requisite limits of practice, by suitable variation of the number, size and arrangement of the conductor members. In such an annular or polygonal system of conductor members, each conductor member acts primarily as an independent discharging surface, but is subject to modification or control by the electrostatic efi'ect of the adjacent conductor members, the presence of the conductor members at either side of any one of said members tending to reduce or lower the electric field intensity directly adjacent to such member, and to correspondingly reduce the discharge therefrom. This may be more fully explained by reference to Fig. 4 wherein a series or plurality of discharge conductor members 1 are arranged in an annular or polygonal system within a pipe electrode 4, said conductor members 1 being formed as wires extending parallel to the axis of said pipe, and being held by supporting means 7 and 7 so as to be in spaced relation to one another and to the wall of the pipe. \Vith such a construction the equipotential surfaces due to the electrification of conductor members 1, will be due primarily to induction or electrostatic action from the charge on the nearest conductor member, modified by the action from adjacent conductor members, and in general, the effect of the adjacent conductor members, with the system of conductor members arranged as described, is to reduce the field intensity at each conductor member compared with what it would be if such adjacent conductor members were not present. This modification or control of the electric field intensity adjacent to the conductor members is illustrated in Fig. 5, by the dotted traces of the equipotential surfaces on a plane normal to the axis of the system of conductor members. As shown in this figure, the curvature of these surfaces is intermediate between the curvature which would be due to each wire acting alone, and the curvature which would be due to a single conductor of the same diameter as the whole system of conductor members. Therefore, by suitably subdividing the discharge elec trode into conductor members and arranging such members at suitable distance from one another and from the opposing electrode, I am enabled to either reduce or increase the field intensity adjacent to each discharging electrode member, and to correspondingly control the resultant discharging action from said electrode, and at the same time to maintain the proper intensity of the electrostatic field as a whole, so as to insure effective action, for example, in electrical precipitation of suspended particles from a gas passing adjacent to such discharge electrode. Thus, if less discharging action and greater electrostatic field strength is desired, the conductor members 1 will be placed closer to one another so as to reduce the field intensity adjacent to each conductor member, and they may also be placed closer to the opposing electrode, so as to increase the electrostatic field strength, or, if it is desired to increase the discharging action and decrease the electrostatic field strength, the conductor members may be spaced farther from one another and from the opposing electrode- My invention is not limited to any special form of collecting or opposing electrode, the
discharge electrodes above described being applicable in connection with any suitable collecting or opposing electrodes.
What I claim is:
1. In an apparatus for electrical precipitationof suspended particles from gases, a
of conductor members in such spaced relation that the electric field intensity adjacent to each conductor member-is reduced discharge electrode'comprising a plurahty of conductor members arranged in polygonal' order.
3. In an apparatus for electrical precipitation of'suspended particles from gases, a discharge electrode comprising a plurality of conductor members extending parallel to one another and electrically connected together, said conductor members being in such spaced relation that the electric field'intensity adjacentto each of said members is reduced by the influence of the adjacent conductor members.
4. An apparatus for-electrical precipitation of suspended particles from gases, comprising a collecting electrode exposed to the gas to be treated and .a discharge electrode also exposed to the gas to be treated and arranged opposite said collecting electrode and membersconnected toget comprising a plurality of 1parallel conductor er and arran ed in such spaced relation that the electrical field intensity adjacent to each conductor member is controlled by the influence of each adjacent conductor member.
5. In an apparatus fer electricalprecipitation of suspended particles from gases, the combination with an electrode fomed as a pipe and adaptedto receive the gas to be treated, in contact with the electrode surface, of a discharge electrode comprising a plurality of elongated smooth conductor members extending longitudinally in said pipe and arranged in such spaced relation relatively to one another and to the Wall of the pipe, that the electric field intensity adjacent to each conductor member is controlled by the influence of adjacent conductor members.
6. In an apparatus for electrical precipitation of suspended particles from gases, a collecting electrode formed as a pipe and a discharge electrode comprising a plurality ofsupporting devices and a plurality of conductor members extending between said supporting devices and supported thereby in spaced relation, in a polygonal system.
7. In an apparatus for precipitatingsuspended particles from gases, an electrode formed as a pipe; and a discharge electrode comprising a plurality of conductor members extending parallel to the axis of said pipe and arranged in a polygonal system.
8. In an apparatus for precipitating sus pended particles from gases, an electrode formed as a pipe, and a plurality of discharge electrode members extending arallel to the axis of said pipe and spaced rom one another and from the Wall of the pipe.
In testimony; whereof I have hereunto set my hand, at 0s Angeles, California, this 2nd day of June 1915.
WALTER AUGUST SCHMIDT.