US2016531A - Electrical treatment of fluids - Google Patents

Description

Oct. 8, 1935. H. AQW ERMUTE 2,016,531

ELECTRICAL TREATMENT OF FLUIDS Filed May 8, 1934 3 Sheets-Sheet l Gum/M41 1935- H. A. WINTERMUTE 2,016,531

ELECTRICAL TREATMENT OF FLUIDS Filed May 8, 1954 s Sheets-Shet 2 7 Oct. 8, 1935. H, A. WINTERMUTE ELECTRICAL TREATMENT OF FLUIDS Filed May 8, 1954 3 Sheets-Sheet 5 /f g6 I WW3 i uunnnu HM? a, WW

Patented Oct. 8, 1935 r Harry A. Wintermute, Plainiield, N. 1., assignor to Research Corporation, New York, N. Y., a

corporation oi New York Application May 8, 1934, Serial No. 724,579

17 Claims.

, impressed upon a fluid treating circuit at the same polarity, and which bring about changes,

in the characteristics, especially as regards frequency, wave shape and duration, or the impulses or energization periods so that the beneflts'of such changes and the control thereof can be.

realized in the treatment of fluids.

' The invention is more particularly directed to the provision of means for electricallytreating a fluid whereby the fluid is subjected successively to electrical impulses of difierent characteristics; that is, the means provide the treating circuit at one instant with an impulse or energization period possessing certain characteristics and follows this, in rotation or in alternation or successively, with impulses possessing diflerent characteristics.

Another object is to provide a high tension electrical circuit for the energization of a plurality of fluid treater units whereby one of the units can be energized mm the circuit with impulses oi certain characteristics and another unit can be energized from the same circuit with impulses possessing diiferent characteristics. Electrical precipitators oi the Cottrell type comprise a casing with inlet and outlet for the gases to be treated and two'groups of opposing electrodes within the casing which are insulated from each other. In operation, the opposing electrodes, are maintained at a high potential diiference while the gases to be treated are passed through the strong electric fields thus created. It is common practiceto have the electrodes of one group oi relatively flat contour, while the opposing electrodes are wires or chains which are insulated from the flat electrodes and maintained at high potential difference irom them. The flat electrodes are termed collecting electrodes because most of the suspended material removed from the gases collects upon them. The wire electrodes, or other electrodes of small cross section, are called discharge electrodes because the electric field in their immediate vicinity is very intense and corona discharges emanate from nated by numeral which is connected to conductor ll.

their surface. The gases are subjected to electronic bombardment asthey pass through the strong electric fleids and become ionized. The free electrons and ions moving under the force of the electric fields become attached to, and are instrumental in removing, the suspended particles in the gases.

The manner in which the'objects oi the invention can be realized will be illustrated with the accompanying drawings, in which:

Fig. 1 shows more or less diagrammatically the electric circuit including a treater in sectional elevation; I Fig. 2 shows a plan partly in section or the treater shown in Fig. 1;

Fig. 3 is a fragmentary view of a portion of the treater shown in Figs. 1 and 2;

Fig. 4 is a'detailed view 0! an adiustable synchronous, switch;

Fig. 5 is a diagram sh arrangements of the connec ons shown in Fig. 1; and I Figs. 6,7, 8 and 9 are diagrams showing other arrangements embodying the principles of the invention. v I

In Fig. 1 the low voltage supply circuit desigl is shownasathreephase circuit, although two phase and even single phase can be used. The low voltage circuit I, controlled by switch H, energizes synchronous motor 2 which is connected, by shaft 3 to mechanical rectifying switch 4 and distributing switch 5. Also energized from the low voltage circuit is trans former l5, which receives current through the single phase branch circuit i2, taken of! two wires of circuit l. Switch II and ohmic resistance l4 permit this circuit to be suitably controlled. Rectifying switch 4 is of the familiar type wherein the rotor comprises four insulating arms 6 with metallic tips I which support two jumper wires 8. 40 When this rotor is revolved in synchronism with the current supplied through transformer ii, for example, at 1800 R. P. M. for cycle current, all half waves of electrical energy of one polarity alternately impressed upon first one and'thenthe 46 other oi shoes :1 are directed to the adjacent shoe III which is connected to conductor l6. Similarly all half waves of electrical energy of opposite polarity are directed to the other stationary shoe Ill Conductor 60 I6 is connected through conductors l8, l9 and 20 to a condenser 2!, to be later described, which temporarily stores the electrical energy which is supplied by transformer i5. Conductor i6 is also connected to switch I which revolves in synchrocertain alternative nism with the half waves and dictributes them to the precipitator units as desired after they are given the desired steep wave front characteristic ling the voltage in that part. of the circuit including the condenser and precipitator units.

The gas treater is included in casing which has inlet 3! and outlet 32. It includes two units of the usual plate type which are marked 33a and 331). These comprise collecting electrode plates 34 and discharge electrodes 35. Intermediate the treater units 33a and 33b is a condenser unit 28 which is made up of plates 36 and rods 31. The rods 31 are of appreciable diameter as compared with the wires or edges which make up discharge electrodes 35,because it is desirable that no corona discharges emanate from these rods and permit electrical energy temporarily held by the unit to leak away. Unit 28 functions, therefore, as a I condenser with a gaseous dielectric and in the present circuit it is used for temporarily storing the electric impulses that energize the ionizing electrodes of the treater. It functions also as an electrical precipitator of the non-ionizing type and removes from thegases passing through it those particles which carry free electric charges 'of appreciable magnitude.

. The circuit is completed by means of conductor l! which connects shoe in with casing 30 of the gas treater. The casingis in mechanical and electrical connection with the various collecting electrodes. side of the circuit is usually grounded as shown at 6!.

In the operation of the circuit, a half wave of electrical energy from transformer l5, say of negative polarity, is directed by switch 4 to conductor l6 and reaches unit 28 through conductors i9 and 20. This energy is released when the rotor of switch 5 assumes a position which will permit the passage of current from conductor 20'to conduc tor 2i through switch shoe 20', jumper 8 and shoe 2|. This impulse rapidly built up (or rebuilt) by the release of the energy stored in condenser 28-, through the two air gaps on switch 5 which are included in the circuit between conductors 20 and 2 i, has a very steep wave front, and when this is impressed. upon theelectrodes of treater 33b,

the gases passing through that treater become highly ionized. A half cycle later when the rotor of switch 5 has revolved 90 mechanical degrees, condenser 28, which in the meanwhile has absorbed another half cycle of electrical energy of although the precipitating efllciency of the units of the units 33c and see. The same result may be obtained by inserting a spark gap in place of may be slightly less than if every impulse was sent to each unit. The latter condition may be obtained by inserting a jumper wire 23 between switch 5. Fig. 5 shows such a circuit with spark gap 52 taking the place of the rotating gaps of switch 5.

v It has been found advisable, in operating .the equipment just described and in using the high wave front impulses that result from it, to design the equipment with consideration of the characteristics of this type of impulse. It has been found advantageous to eliminate sharp turns in the conductors as far as possible, and where air insulation has been used it has been increased over common practice for sine wave current to prevent corona losses. .It has also been found advantageous to insert choke coils in parallel circuits in order to obtain a better distribution of the energy in the various conductors. The manner of using these choke coils is shown in Fig. 1 where coils 26 slightly check the rush of current as it leaves the inlet conductor 25 and divides in order to energize discharge electrodes 35 from both top and bottom. Mounted near the top of each discharge electrode is a small choke coil 28 which may be of one or more turns, but preferably is a very simple air choke of few turns which is not appreciably ail'ected by dust falling upon it and which retards, only high frequency or very steep wave front oscillations. Similar coils are provided at the bottom of the discharge electrodes r as shown at 21.

1 As is well known, the electrical characteristics of electrodes change when they become covered with material removed from the gases. This is particularly true when the material is of a non conducting nature or is a heterogeneous mixture 01. particles having different electrical character istics. It is desirable that the electrodes of the precipitator shown in the'flgures be kept clean in order that the efliciency of the precipitat'or be maintained and because certain of the electrodes -those designated 'as 36 and tt-constitute a condenser which is a vital part of the electric circuit and must be kept free of precipitated material if the condenser is to have a constant capacitance. It is important, therefore, that eiiicient cleaning means be provided to maintain the electrodes free from the precipitated material. Referring to Fig. 1, the discharge electrodes are suspended from a central vertical support 3!! which-depends from and passes through an insulating chamber 39which may be of insulating 50 plate 4|, which may be of metal, on top of cham-' ber 39. A hammer mechanism 42 is periodical ly raised and dropped to impart blows to the support 38 and this causes a jarring of electrodes 35 which effectively removes any material that may collect upon them. The collecting plates 340i units 83a and 33b depend from transverse members 43 which are positioned transversely in casing 30 and are supported at the sides of that casing. While these electrodes are adequately supported and spaced by members 43, they are free to vibrate when rapped. Near the lower ends of the electrodes, where movement of the same is more readily possible, transverse rapping means are provided. The rapping means may be at or near the bottom of the electrodes, as shown in Fig. 1, and may consist of stifl'members 44 upon which are held rigidly the hammer means i5 shown in Fig. 3. The electrode surfaces, where the hammers 44 strike, are reinforced by stiffening plates 48. The distance "d between the faces of opposing hammer means is slightly a plate 34 with two reinforcing plates 46 upon it. If then a member 44 can be made to rapidly move back and forth transversely of the plates,- the plates will receive a jarring which will effectively dislodge deposits of dust and the like that are clinging to it. This movement of members 44 is accomplished by securing them to eccentric straps 41 which in turn ride on eccentrics 48 on revolving shaft 49 which is revolved by motor 50 through reduction gear 5|. It has been found beneficial to make the movement of the eccentric slightly greater than the distance between the faces of the hammer members. For example.

if member 44 is moved of an inch and if the distance. the hammer can move before striking plate 46 is only the hammer means will have to move the plate /8" after striking it. This insures a positive striking and jarring of the plates by the hammer means on rods 44.v

When only a few light plates are to be jarred a single member 44 will jar the rods without detrimental efiect to the precipitator structure generally, but when the platesare large, especially when there are many of them in parallel across the casing of the precipitator, it has been found that to hit all the plates on one side simultaneously not only requires considerable power but it tends to move the precipitator laterally to a detrimental degree. In the present construction this is avoided by dividing the plates into two approximately equal groups and jarring the groups separately. This is shown in Fig. 3 where one member is is jarring half the plates from one side, while another member 44 is jarring the other half of plates from the opposite side. This tends to neutralize the side motion of the plates with the result that the precipitator as a whole receives no lateral motion.

Switch 5 in Fig. 1 can be adjusted angularly on shaft 3 which makes it possible to discharge condenser 28 at the desired instant in the energization cycle, and the shape and spacing of tips 1 can be altered thereby changing the characteristics of the spark gaps between tips I and.

the stationary shoes 2 I and 22 of the switch.

When jumper 23 is removed the switch can be made to distribute the energy so that two units will receive energy separately, which is an especially useful condition when the units have different electrical characteristics.

Fig. 4 is a detailed showing of an adjustable distributing switch suitable for use at 5 in Fig. 1, and shows means for independently varying the length of the spark gap and the relative position of the contact in each of the energized circuits.

The shoes 20', 2i and 22 of the switch are carried by bolts A, C and D' mounted in slots in the supporting members A, C, and D. The length'of the spark gaps may be varied by moving the shoes towards or away from the tips I by means of the bolts. It is to be noted that spark gaps. of different lengths may be provided at each ofthe shoes, so that impulses of different characteristics may be applied to successive treater units or successively to the same treater unit according to the electricalcircuit used, as was described with reference to Fig. 1.

The relative position of the spark gaps in the cycle may bevaried by angularly rotating the shoes along the slots in the supporting members A, C, and D so that one circuit may be closed at a point of lower voltage during one half wave than the other circuit during the succeeding half.

wave. 7

circuit.

The movable shoes'lli', 2|"and 22' are advantageously split into two portions which slide over each other, so that the length of the shoes may be varied individually.

It will be seen that this synchronous spark 5 gap switch, makes it possible to supply impulses of widely varying characteristics either to sucthus permitting one set of electrodes to be energized from one half of the wave with impulses 20 having different characteristics from those applied to the other set of electrodes during the suceeeding half wave.

lf the top shoe and one of the other shoes are adiusted to contact with the rotor tips normal 25 energization will be provided during one half wave and impulse or steep wave front energizatlon during the succeeding half wave when the discharge takes place across the gap between the third shoe and the rotor tips.

In many installations there is no particular advantage gained through the use of such a distributing switch and an ordinary spark gap can be substituted for it as shown in Fig. 5. In this arrangement of the circuit the members and conular conductor and not supplying energy to the 45. other conductona condition which has been found to exist in varying degrees when steep wave front impulses are utilized in circuits of the nature described. The discharge electrodes are indicated as wires in cross-section at 56, and the collecting electrodes 51 are common to all the units. The numeral 58 identifies insulated non-discharging electrodes which are a part of the condenser unit.

They are shown in thisflgure as plate-like members. v

Fig. 6 shows a diagram of 'a system embodying the invention wherein four thermionic rectifiersare utilized to provide impulses of different characteristics during successive half waves or cycles.

The system is shown operatively connected with two precipitator units and an intervening condenser unit as in Fig. 5. In the figure T indivcates a high voltage transformer connected at each end to the discharge electrodes of one of the units through thermionic rectifier K, resist-' ance R, adjustable spark gap 52 (52') ad usted. by'means of screw mechanism C, C (A, A) and conductor 53 (5,4) The ends of the transformers are likewise connected to the collecting electrodes through thermionic rectiflers, while the circuits to the discharge electrodes are separately connected to the condenser plates 58 (58') between the thermionic rectifier and the spark gap in each- A direct connection F with high voltage switch E is provided between each circuit.

With both spark gaps open and switch E open, each treater unit will be supplied with steep wave front impulses of independently variable characteristics, in alternate half wave periods. If switch E is closed, both treater units will be energized simultaneously, with impulses of alternating characteristics. K

If one of the spark gaps is closed and switch E is open, one of the treater units will be normally energized while the other will be energized with steep wave front impulses in the succeeding half wave periods. If switch E is closed, the treater units will be simultaneously energized normally and with steep wave front impulses in successive half wave periods.

Fig? shows a system of-energization utilization, a middle transformer top and two thermionic rectifiers K. The connections between the transformer and the treater units are the same as in Fig. 6, except that instead of connecting the ends of the transformer with'the collecting electrodes through thermionic rectiflers, the mid point of the transformers is directly connected with the collecting electrodes. This system maybe operated similar to that shown in Fig. 6. However, the potentials available in the system of Fig- 7 will only be half those available in the system of Fig. 6, if all other conditions are the same.

In Fig. 8 is shown a system utilizing a rotary switch 5 for connecting alternate half waves to successive .treater units. With this system the different treater units may be energized with impulses of diflerent frequencies (if one of the spark gaps 52, 52' is closed one of the treater units will be normally energized), but does not permit energizing a single treater with successive im; pulses of difierent characteristics.

Fig. 9 shows a system having similar operating characteristics to that of Fig. 8, but utilizing two thermionic rectifiers K in place of the rotary switch I.

The parts of condenser 28, as shown in Fig. l, are spaced and supported in much the same way as those in units 33a and 33b, but, whereas separate electrical connections are made to the high voltage electrodes in the latter units, as indicated by conductors 24 passing through insulating bushings 59 and insulating plates 60, connection 20 is connected to the mechanical support provided for the insulated members of unit 28. It will also be noted that only one rapping member 44 is shown. When the plates of this unit are small and not many in number, a unidirectional rapping voltage condensers, especially when they include a gaseous dielectric, require a great deal of space,

and because of the necessity of placing a safe- '=fguarding structure around such condensers the space required is often more than can be provided adjacent an electrical treater. An advantage ofathe gaseous type condenser is that it is simpler than the condenser with oil or wax as a electrode in the ionizing units. In Fig. 1 only so as to energize dielectric and if kept clean is notlikely to puncture. However, should it puncture, no damage is done as the dielectric is self-healing. Another advantage of this type of condenser is the rapidity same. As illustrated, the condenser functions as part of. the precipitating apparatus and has a definite part in the removal of suspended par.- ticles from the gases. If in a particular problem there is no great advantage in having it function in this way, it can be placed in any position in the gas stream. In the use of a revolving switch to furnish spark gaps and to distribute the energy impulses great flexibility is afforded. Not only can the gaps be changed in length and the time 15 when breakdown is effected be controlled but its use makes easy the energization of precipitator units every other half cycle, which tends to decrease the amount of energy required for the operation of a precipitator with a plurality of units.

It has been found that the capacitance of a condenser used in the manner described should preferably be at least asgreat as the capacitance of all the precipitating imits to which it is connected.- For example, if the rods in'v unit 28 in Fig. l are in outside"=diameter and spaced 2" apart along the flue, the discharge electrodes can be .05" in diameter and positioned 6" apart along the flue. The collecting-plates 34 can be 8" apart in all units, but this is not necessary if there is any reason for changing the spacing in the condenser unit. It is preferable that with the dimensions above given there should be one nonionizing rod in the condenser for every discharge one red is shown for every two discharge wires, but that is because only one set of discharge wires is being energized at a given time. If both units were energized at the same time, which would be true if Jumper 23 was in place, then the 40 capacity of the condenser should be doubled over that shown.

It is, of course, not necessary that the apparatus be constructed exactly as shown in the drawings or described inthe above specifications.

Many changes in size, shape, and arrangement of partsmay be possible or desirable. For instance, while it is pointed out that satisfactory results are obtained when the capacitance of the conwith which it takes a charge and discharges the 5 denser is equal to the capacitance of the ionizing 50 units to which it is atany one time connected, it is advisable at times to increase the capacitance of the condenser to at least twice that of the ionizing units. The energy directing means may be a thermionic valve or several such valves connected to permit only unidirectional flow of electric current. A spark gap of great flexibility is made possible by the described synchronously rotated mechanical switch with so-called stationary shoes on adjustable supports which permit the shoes to 60 be individually moved radially and angularly with respect to the axis of rotation; and the shoes may be of different lengths. {Other changes will be obvious to those skilled in the art which can be made without departing from the scope of the invention, which broa y comprises means for impressing high tension electrical impulses of steep wave front and short duration across the complementary electrodes of a device for subjecting fluids to electrical treatment, said means essentially comprising a source of high tension alternating current, means for rectifying such current, means for setting up steep wave front impulses and means for distributing such impulses fluid treating means with steepiii wave front impulses having successively different characteristics. 1

This application is a continuation-in-part of application Serial No. 670,558, Fluid treaters, filed May 11, 1933.

I claim: I

1. An electrical circuit for impressing electrical potentials across the complementary electrodes of devices for subjecting fluids to electrical treat ment comprising means providing high tension alternating current, means including a spark gap and a condenser to convert successive half waves of. said current into steep wave front impulses of alternately different characteristics and energy directing means for impressing said impulse across said complementary electrodes.

2. An electrical circuit for impressing electrical potentials across the complementary electrodes of devices for subjecting fluids to electrical treatment comprising means providing high tension alternating current, means to convert successive half waves of said current into steep wave front impulses of alternately different characteristics, and energy directing means for impressing said impulse across the complementary electrodes of a plurality of treating devices in succession.

3. A system for electrically treating fluids comprising a source of high voltage alternating current, a treater unit including spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current including a spark gap and a condenser to convert successive half waves of said current into steep wave front impulses of. alternately different characteristics and energy directing devices adapted to impresssaid impulses across said electrodes.

4. A system for electrically treating fluids comprising a source of high voltage alternating cur rent, a treater unit including spaced electrode members, and, means connecting said electrodes with said source of high voltage alternating current including means to convert successive half waves of said current into steep wave front impulses of alternately different characteristics and energy directing devices comprising thermionic rectifiers adapted to impress said impulses across said electrodes.

5. A system for electrically treating fluids comprising a source of high voltage alternating. cur

' rent, a treater unit including spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current including means to convert successive half waves of said current into steep wave front impulses of alternately different characteristics, and energy directing devices comprising rotating switch rectiflers operated in synchronism with the variation in voltage of the current adapted to impress said impulses across said electrodes.

6. A system for electrically treating fluids com- 7. A system for electrically treating fluids comprising a source'of high voltage alternating current, a treater unit including spaced electrode members, and means connecting saidelectrodes with said source of high voltage alternating current including an adjustable spark gap and a condenser to convert successive half waves of said current into steep wave front impulses of 5 alternately different characteristics, and energy directing devices adapted to impress said impulses across said electrodes.

8. A system for electrically treating fluids com-' prising a source of high voltage alternating cur-' rent, a treater unit including spaced electrode members, and means connecting saidelectrodeswith, said source of high voltage alternating current including an adjustable rotary spark gap rotatable in synchronism with the variations in l5 voltage of the current and a condenser to convert successive half waves of said current into steep wave front impulses of alternately different characteristics, and energy directing devices adapted to impress said impulses across said electrodes. 20

9. A system for electrically treating fluids comprising a source of high voltage alternating current, a treater unit including spaced electrode members, and means c ecting said electrodes with said source of high.' voltage alternating current including a rotary spark gap rotatable in synchronism with the variations in voltage of the current and having .means to vary thewidth of the gap to convert successive half waves of said current into steep wavefront impulses of alternately different characteristics, and energy d recting devices adapted to impress said impulses across said electrodes. 4 r

10. A system for electrically treating fluids comprising a source of high' voltage alternating 85 current, a treater unit including spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current including a rotary. spark gap rotatable in synchronism with the variations in voltage of the 40 current and having means'to vary the duration of the spark to convert successive half waves of said current into steep wave front impulses of alternately different characteristics, and energy directing devices adapted to impress said impulses across said electrodes.

11. A system for electrically treating fluids comprising a source of high voltage alternating current, a treater unit including spaced electrode members, and means connecting said electrodes with said source of ,high voltage alternating current including av rotary sparkgapmotatable in synchronism with the variations in voltage of the condenser andhaving means to vary thetime of discharge relative to said variations in voltage to convert successive half waves of said current into steep wavefront impulses of alternately different characteristics, and energy directing devices adapted to impress said impulses across said electrodes.

'12. A system for electrically treating fluids comprising a source of high voltage alternating current, a plurality of treater units each including spaced electrode members, means connecting said electrodes with said source of high voltage alter- 65 nating current including means to convert successive half waves of said current into steep wave front impulses of alternately different characteristics, and energy directing devices adapted to impress said impulses of varying characteristics across said electrodes.

spaced electrode members, means connecting said electrodes with said source of high voltage alternating current including means to convert successive hali waves of said current into steep wave front impulses of alternately different character- 'istics, and energy directing device's adapted to alternating current including means to convert successive half waves oi said current into steep wave front impulses of alternately diflerent characteristics, and energy directing devices adapted to impress said impulses of varying characteristics across the electrodes of a plurality of units.

15. A system for electrically treating fluids comprising a source of high voltage alternating current, a treater unit including spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current, including means to convert alternate'half Waves of said current into steep wave front impulses and energy directing devices adapted to impress said impulses and the unconverted hall waves across said electrodes.

16. A system for electrically treating fluids comprising a source 01' high voltage alternating current, a plurality of treater units including 6 spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current, including means to convert alternate hali waves of said current into steep wave front impulses, and energy directing 10 devices adapted to impress said impulses and the unconverted half waves alternately across the electrodes of a plurality or treater units in succession.

17. A system for electrically treating fluids comprising a source of high voltage alternating current, a plurality of treater units including spaced electrode members, and means connecting said electrodes with said source of high voltage alternating current, including means to convert alternate half waves of said current into steep wave front impulses and energy directing devices adapted to impress said impulses and the u'nconverted half waves across the electrodes of a plurality of units.

HARRY A. WIN'I'ERMUTE.

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