US2604184A

US2604184A - Electrostatic precipitator

Info

Publication number: US2604184A
Application number: US62932A
Authority: US
Inventors: Ray W Warburton; Frank W Morley
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1948-12-01
Filing date: 1948-12-01
Publication date: 1952-07-22
Anticipated expiration: 1969-07-22

Description

y 22, 1952 R. w. WARBURTON ET AL 2,604,184

ELECTROSTATIC PRECIPITATOR 4 Sheets-Sheet 5 Filed Dec. 1, 1948 7 m mm; W WW1: ii 4 m H A/ LHTW m WM m a u v W 2 ma JTTL 1 m- PM? w W M 4 m M a m m n H W 4 6H H 2 7 T u. i 2 2 M W -u||n WM LIA H &. W

Patented July 22, 1 952 ELECTROSTATIC PRECIPITATOR Ray W. Warburton, Medfield, and Frank W. Morley, Westwood, Mass, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 1, 1948, Serial No. 62,932

12 Claims.

This invention relates to electrostatic precipitators for the removal of small foreign particles, such as dust, from gases, such as air, and relates more particularly to systems for the washing of the electrodes of such precipitators.

The electrodes of electrostatic precipitators, after periods of use, become so coated with collected matter that for emcient operation it is necessary to clean them. A satisfactory method of cleaning the electrodes is to wash them down with a flushing liquid, such as a light oil. In some installations, where large volumes of gas are treated, a large precipitator is used and one section of it is rendered inactive and its electrodes afterwards reconnected. Its electrodes must be washed the proper amount, and then, after washing, must be properly drained before being placed back into service. The various controls must be operated in the proper sequence and must be accurately timed. In a multi-section precipitator, much of the washing and other equipment is .common to all of the sections, and it has been found difficult to isolate one section for the washing of its electrodes without interfering with the operation of the other sections. Another disadvantage of a multi-section precipitator is the difficulty ofadapting it to handle different volumes of gas.

This invention provides a relatively small, electrostatic precipitator which can be used alone for cleaning a relatively small volume of gas, or in multiple for cleaning any desired volume of gas. Each precipitator contains its own equipment for automatically removing it from service, for washing its electrodes, and for returning it to service. All an attendant has to do is to actuate one control when a precipitator is ready for its electrodes to becleaned, following which, its gas inlet and outlet are closed, its electrodes are disconnected from their power supply source, the pump for supplying the washing liquid to the spray headers is started, the headers containing the electrode washing nozzles are moved from a parking position spaced from one end of the electrodeswhere they are normally out of the gas stream, to the other end thereof where the movement of the headers is reversed and they are returned tothe parking position. When the headers reach the end of the electrodes adjacent the parking position on their outward movement, the spray of the flushing liquid upon the electrodes is started, provided the temperature of the liquidis above a predetermined minimum. If not, the liquid is not sprayed, and the movement of the headers is stopped until the liquid reaches the proper temperature. When the headers are returned to the parking position, they are stopped there, and a timer is started which provides a delay period suitable for the draining of the flushing liquid from the electrodes, following which, all controls are returned to normal, the pump is stopped, the gas inlet and outlet are opened, the electrodes are reconnected to their power supply source, and the precipitator is returned to service. The operations described in the foregoing are automatic, are in proper sequence, and are properly timed.

Another feature of the invention is that when an attendant initiates the described operation in a particular precipitator, a light on the control panel is lighted, indicating that that precipitator is out of service, and a timer is started which, if the operations described in the foregoing have not been completed in the proper time, will actuate an alarm signal.

, An object of the invention is to provide an improved, automatically operated, control system for removing an electrostatic precipitator from service, for washing its electrodes, and for then restoring it to service.

The invention will now be described with reference to the drawing, of which:

Fig. 1 is a diagrammatic view illustrating the connection of several electrostatic precipitators embodying this invention, in multiple in common gas inlet and outlet ducts;

Fig. 2 is a diagrammatic view illustrating the connection of the precipitators of Fig. l to a common, flushing liquid supply source;

Fig. 3 is a diagrammatic view,'in side-elevation,

- the sprockets 35, and the chain 35.

of a portion of an electrostatic precipitator with 'More or fewer precipitators could be used, de-

pending upon the volume ofdirty gas to be cleaned.

Fig. 2 illustrates the four precipitators with their control panel, and with acommon fiushingg. v A common, liquid. supply pump normally closed, energizing circuit of the solenoid.

liquid sump i2.

i3 driven by an electric motor: i4, .suppliesl flushing liquid from the sump l2 to each of the 'pre-' cipitators when it is its turn to be washed. The 7 pump 15, driven by the electric'motor i6, recir culates the liquid in the sump I2 through'the I cleaner [7 in which the foreign matter therein is removed, and through the heater i8 which main tains the liquid at the proper temperature, which may be 180P'F. for handling. The liquid used may be a light, petroleum-base oil.

.Referring now to Figs. 3' and 4, the casing of each of the precipitators contains the superim posed collector cells 28 with the Wire ionizer electrodes 2i and the tubular ionizer electrodes 22 arranged; upstream with respect .to gasxflow, thereof- The vertical spray header 24 is movable by the screws 25 threaded intoits end fitting 26, horizontally between. the ionizer electrodes and the collector cells, and has the upstream spray nozzles 21' for spraying liquid upon" the ionizer electrodes, and has the downstream, spray nozzles 28 for spraying liquid-upon the plates of the collector cells. The vertical spray header 3!) is movable bythe screws 29 threaded into its endfitting 3i, and has the upstream nozzles '31 for spraying liquid upon the collector: cells from their rear. I

The

screws

25 and 29* are rotated by the electric motor 32 through the belt 33, the pulley 34,

The inlet louvres 38 are in the'upstre'am' sideoi the; precipitator casing, and the outlet louvres are in the downstream side of the casing. The components described in the foregoing are disclosed in detail in theR. L. Lincoln application,

Serial No. 52,329, filed October 1, 1948;

'Normally during the gas cleaning operation,

the headers 24 and 39 are located in the park-- ing space 43 which is an open space to one side of-tne inlet, the outlet, and the electrodes'of the precipitator, so as to be completely outside the gas stream being cleaned;

' energizing circuit of the timerifil -for-the alarm -52. Atthesame time the relay i8 is energized 4 I and pulls up its armature 19 against the contact 88 which is in a circuit including the drain timer 53 and normally open contacts of the switch 68, placing the timer 53 in condition for operation when the contacts of the switch 68 close. At the same time the relay 9! is energized and pulls up its armature as against the contact 99 and closes the energizing circuit including normally closed contacts in the drain timer 53 and the thermostat Se, of the pump motor i 6, starting the pump if the temperature of the liquid in the sump where: the thermostat is.lecated;-is above say 180 Fl At the same time' the rlelayiSl is energized and pulls up its armature 82 against the contact 33 which is in a circuit including the solenoid 55 which actuates the valve 56 in the liquid supply piping to the headers, the thermostat and-contacts in theswitch 4 5. At the same time themelayfifi is energized and pulls up its armature-'36 awayimm the contact 81 opening the ply'line'to the cylinders 69 and 6!.

The energizing circuit of the power pack 4! includes normally closed contacts of the singlepole, double throw switch 62. V

Theinput connections to thereversingcircuit 6'! of the motor 32 includes normally open contacts or" the switch 62, normally closed contacts of the switch 68, andcthe armature 92;; and the contact 93 of therelayfil.

When-the solenoid 5] is deenergized by the relaytt, it opens the valve 58, causing liquid to be supplied tothe hydraulic cylinders fifl and 6i which then act. to close the inlet louvres 38 andthe outlet louvres 45. The closing of the inlet louvres actuates the switch 62 which opens the energizing circuitofthe power packet, and closes the energizing circuitto the motor reversing circuit 61, causing the motor 32 to be energized, following which, it starts to move the

headers

24 and 30 from the parking space towards: the collector cells. a,

When the ,headerZt reaches the left handend (facing Fig. 4 of the drawing) of the collector cells, it .trips the switch 44- and completes through the thermostat 65 in. the liquidsupply piping to the headers, the-energizing circuit of the solenoid, 55 of thevalve 56, ifv the tempera.- ture of the liquid is abovev? .F., so that liquid is supplied to the spray. nozzlesin the headers. If. the temperature is below '7 l R, the thermostatte opens the supply-circuit to the motor32 by energizing the relay-. 9! which pulls up.:its

I armature 92 away from the'contact 93,.and opens the. energizing circuit of the solenoid 55.. This results in the closing-of the valve 56 and the prevention of the supply of liquid to thespray lect'or-cell, it trips the switch 65 in the motor reversing circuit, causing it to close the energizing circuit of the solenoid 94 which then retracts itsplunger" to whichthe' reversingswitch oi -the motor reversing circuit is I attached, causing-the field and armature of the motor to be soconnected as to cause the motor to reverse. The motor then moves the '-l1eader's back towards the-parkingspace 43. Whenthe header 7 L e-"reaches the switch 4 fl,-- it. again trips the switch, causing it toopenthe circuit of the sole-F hold '55 and to thereby cut off the supply. of liquid to'thespray-nozzles. Theheaders continue to move until they reach the parking space 43 where the header 24 trips the switch 68 which then opens the motor reversing circuit. 6'! and stops theheader motor 32... .1: 4 1

: At this time the switch 68 closes contacts completing the, circuit to thedrain timer 53, causing it.to'. start timing. After a period of time sufficient for the sprayed electrodes to have drained properly,ithe timer 53 first stops the pump motor [4 fordiscontinuing the building up of oil pressure, and then closes the energizing'circuit of the solenoid 95 which moves the switch. 12 fromthe contact 96, and opens the energizing circuit of the relays H, l5, [8, 8i and 85gand thus resets the controls in the control panel to normal, following which the valve 56 is closed, the hydrauliccylinders 66 and 6| open the inletand outlet louvres, thepressure in the cylinders, being released through the drain pipe '10, the power pack 4| is again energized, the wash signal ,50 is turned off, and the alarm timer 5! is deenergized.

If for any reason the sequence of operations described in the foregoing is not completed in the proper time, the alarm 48 is actuated bythe timer 5|. V V

The timers 5| and 53' are conventional reset I timers such 'asare manufactured by the Eagle Signal Company, and which reset their contacts to normal when deenergized. I V I Fig. 3 illustrates the

switches

44, 66 and 68 schematically without showing their physical locations which areshown by Fig. 4..

The precipitator is now back in service, and the attendant can remove the key from the lock 49, andplaceit in the lock of the next precipitator ,tOabG. washed, following which the sequence of, operations described in, the foregoing is followed in that precipitator.

While one embodiment of the invention has been describedfor the purpose of illustration, it shouldbe understood that the invention is not limited to the exact apparatus and arrangement of apparatus illustrated, as modifications thereof may be suggested by those skilled inthe art, without departure from the essence of the invention'. I

What is'claimed is:

l .1. An electrostatic precipitator comprising a casing having agas inlet and a gas outlet, electrodes in said casing between said inlet and outlet, header means movable alongside said electrodes for washing same, means for supplying liquid to said header means, damper means for preventing the flow of gas through said inlet and outlet-means for .closing said damper means, and means including means actuated when said damper means is closed, and including means responsive to the temperature of the liquid supplied by said liquid supplying means to said header means, for starting the movement of said' header means.

2. An electrostatic precipitator comprising a casing having a gas inlet and a gas outlet, electrodes in said casing between said inlet and outlet-and inthe path of the gas stream passing therethrough, said casing having an open space therein, offset with respect to said inlet and outlet and said electrodes, so as to be outside said gas stream and to one side of said electrodes,

I header means for washing said electrodes, said header means beingnormally positioned in said space, liquid supply. meansfor said header means, meansfor moving said header means from said space towards said electrodes, and means including thermostatic means responsive to the. temperature of the liquid in said liquid supply means, andincludingmeans actuated. by said headermeans'when it moves to a position alongside said electrodes, for actuating said liquid supply means to supply liquid to said header means for spraying upon said electrodes.

3..An.electrostatic precipitator as claimed in claim 2 in which the thermostatic means acts to stop the header moving means and the liquid supply means when the temperature of the liquid from the liquid supply means is below a predetermined minimum.

4. An electrostatic precipitator comprising a casing havinga gas inlet and a gas outlet, electrodes in said casing between said inlet and 'outlet and in the path of the. gas stream passing therethrough, said casing having an open. space therein, offset with respect to said inlet and outlet and' said electrodes, so as to be outsidesaid gas stream and'to one side of said electrodes, header means normally positioned in said space, means for moving said header means from said space alongside said electrodes, liquid supply means for said header means, damper means for preventing the flow of gas through said inlet, and outlet, means for closing said damper means, means including means actuated by the closing of said damper means and including thermostatic means responsive to the temperature of the liquid from said liquid supplymeans for starting said header moving means, and means including means actuated by said header means when it moves to a, position alongside said electrodes for actuating said liquid supply means to supply liquid to said header means for spraying upon said electrodes. I v

, 5. An electrostatic precipitator comprising a casing having a gas inlet and a gas outlet, electrodes in said casing between said inlet and outlet and in the path of the gas stream passing therethrough, said casing having an open space therein, offset with respect to said inlet and out. let and said electrodes, so as to be outside said gas stream and to one side of said electrodes, header means normally positioned in said space, means formoving said header means from said space alongside said electrodes, liquid supply means for said header means, damper means for preventing the flow of gas through said inlet and outlet, means for closing said damper means, an electric power supply connected to said electrodes, means including means'actuated by the closing of said damper means for disconnecting said electrodes from said power supply and including thermostatic means responsive to the temperature of the liquid from said liquid supply means for starting said header moving means, and means including means actuated by said'header means when it moves to a position alongside said electrodesfor actuating said liquid supply means to supply liquid to said header means for spraying upon said electrodes.

6. An electrostatic precipitator comprising a casing having a gas inlet and a gas outlet, electrodes in said casing between said inlet and outlet and in the path of the gas stream passing therethrough, said casing having an open space therein, offset with respect to'said inlet and outlet and said electrodes, so as to be outside said gas stream and to one side of the electrodes, header means for washing said electrodes,'elec trically operated valve means for supplying liquid tosaicl header means, said header means being. normally positioned in said space, means for mov-r ingsaidheader means from, said space towards. said electrodes, and means including. an electric switch actuated automatically by said header means :when it moves to aposition alongside. said electrodes, for energizing said valvexmeansfor supplying liquidto said header means for spray.- ing upon said electrodes,

7. An electrostatic precipitator comprising a casing having agas inlet and a gas. outlet, damper means for preventing .the flow of gas through said inlet: and outlet, means for closing said damper means, electrodes in said casing between said inlet and outlet and in the path of: the gas stream passing therethrough, said casing having an open space therein, offset with respect. to said inlet and outlet. and said electrodes, so as to be outside the gas stream and to: one sidev of the electrodes, header means for Washing said electrodes, electrically operated valve means. for supplying liquid to said header means, said. header means being normally positioned. in saidv space, an electric motor for moving said headermeans, means including an electric switch actuated by the closing of said damper means for energizing saidmotor for moving said header means to,- wards said electrodes, and means including an electric switch actuated automatically by said header means when it moves to a position in alignment with said electrodes, for: energizing said valve means for supplying liquid to said header means.

8. An" electrostatic precipitator comprising a casing having a gas inlet and a gasoutlet, electrodes in said casing betweensaid inlet and outlet and in thepath ofthe gas stream passing therethrough, said casing having an open space therein, ofiset with respect to said inlet and outlet and said electrodes so as to be outside the gas stream and to one side of said electrodes, header means normally positioned in said space, means including an electric motor for moving said header means from said space alongside said electrodes, liquid supply means including an electrically operated valve means for said header means, damper means for preventing the flow of gas through said inlet "and outlet, means for closingsaid damper means, means including an electric switch actuated-by'the closing of said damper means for energizing said motor; for starting said header moving means, and means including an electric switch actuated by said header means when it moves to a position alongside said electrodes ior energizing said valve means to supply liquid to said header means for spraying upon said electrodes.

9i An electrostatic precipitator comprising a casing having a gas inlet and a gas outlet, electrodes in saidcasing between said-inlet and'outlet and in the path, of the'gas stream passing therethrough, said casing having an open space therein, offsetrwith respect to, said inlet and outlet andsaid electrodes, so as to be outside: said gas stream and to one side of, said electrodes,

' header means normally positioned in saidspaoe,

"connected to said electrodes, means including. an

electric switch actuated bythe closing of said f 8 damperv 'meansior disconnecting said electrodes from said powersupply and for starting said motor, and means including an electric, switch actuated by said header meanswhen it moves to a position alongside said electrodes for energi'zing said valve means to supply liquid tosaid header means for sprayingzuponsaid electrodes.

10... An electrostatic precipitator comprising a casing having. a gas inletand a gas outlet, elec-,- trodes insaidtcasing between said inletfand outlet and in the: path of the gas stream passing therethrough, said casing having. an: open space therein, offset with. respect! to said.- inlet and, out: let and said electrodes, so as to be outside'the gas stream and to one side or the electrodes; header means for washing said electrodes, said header means: being normally positioned in'said space,- meansincluding an electric motor for moving said header means from-saidspace alongside said electrodes towards the other side thereof, means including an electric switchautomatically operated by said header means when it reaches the other side of said: electrodes for reversing said motor, and means including an electric switch automatically operated bysaid header means when it returns to said space for stopping said motor.-

11. An electrostaticpreoipitator comprising a casing having a gas inlet and a gas outlet,"electrodes in said casingbetween said inlet and outlet andin the path of the gas stream passing therethrough, said casing having an. open space therein, olfset with respect to said inl'et and outlet and said electrodesso as to be ou-tsidethe gas stream and to one side of the electrodes, header means for washing saidelectrodes, said: header means being normally positioned" in said space, means including an electric motor for: moving said header means from said space alongside said electrodes towards the other-side thereof, liquid supply means including electrically operated valve means for said header means, means automatically operated by said header means when it reaches said one side of said electrodes for energizing said valve means for supplying liquid to said header means, means including: an electric switch automatically operated by. said header means-whenit reaches saidiother' side of said electrodes for reversing said motor, means including an electric switch automatically operated by said header means when it. passesfsaid one side of said electrodes for deenergizing said valve means for stopping the supply of liq-uidby said liquid supply means to said header means, and means including an electric switch automatically operated by said header meanswhen it returns to said space, for stopping said motor;

-12'. An electrostatic precipitator. comprising-a easing having a gas inlet and a gas outlet; electrodes in said casing between saidinlet and: outlet andin the, path ofthe gas streampassing therethrough, said casing having an open space therein, offset with respect to said inlet and outlet and said electrodes, S0 as'to be outside the gas stream and to one side of the electrodes,,header means for washing the electrodes, said header means being normally positioned in said space, means including an electric motor for moving said header meansfrom said space alongside said electrodes towards the other side thereof means including an electric switch automatically operated by said header means when it reaches said 7 other side of said electrodes, for reversing said an electric switch automatieall operated by said header means when it motor, means including period of time.

returns to said space, for stopping said motor, and timing means energized by said header means when it returns to said space for deenergizing said motor for a predetermined period of time for preventing said header means from again being moved from said space for said predetermined RAY w. WARBURTON. FRANK w. MORLEY.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 10 UNITED STATES PATENTS Name Date Pegg Nov. 2, 1943 I-I-utchison et a1. Jan. 21, 1947 Pegg Aug. 31, 1948 Penney et a1. Aug. 31, 1948 FOREIGN PATENTS 7 Country Date Great Britain Mar. 1, 1937