DE1911925C - Arrangement for the automatic control of the separator voltage in an electrostatic precipitator - Google Patents

Description

3 1 4

As the first transistor is fed to the emitter terminal B on the emitter side, supplied by the converter W , and on the collector side is connected via a KC circuit to the signal proportional to the separator current and from the tap of the first voltage divider that a breakdown or an arc in the Abferner a through an operating switch operationally separating the signal. The latter is obtained with the help of the emitter of the complementary transistor connected to a photoelectrically connected second voltage divider contained in the control unit St with its tap see semiconductor, which is exposed to the light radiation via a diode in the forward direction with the tap of a glow lamp 1, which is exposed to the first Voltage divider is connected. r28 and r29 would be parallel to the electrostatic precipitator F.

In the case of such a control unit working with thyristors, it is switched and therefore only lights up when

member and one of the control pulses for the thyristors io the separator works; the glow lamp goes out,

delivering tax rate can be the supply of when a flashover occurs in the separator.

Control pulses to the thyristors of the actuator during the construction of the control unit St is based on the

Block occurrence of a flashover in the separator, FIG. 2: It initially contains an equal

wüdurch an increased current after a rollover judge g, preferably in two-way circuit, the over

is avoided and a longer service life of the separator 15 the input terminal B a

Scheiders is reached. proportional tension is applied. At these same

Without special measures, the repeal one could judge g via a resistor R 27, a blocking of the control pulses AEC ülied sudden arrival c6, angeschlosi r26 .. whose resistance r26 comparable "furth est of the precipitator and thereafter is performed changeable ; The variable part of this harmonic of the separator voltage resulting in resistance is a chip through a Zener diode 14. This can be connected in parallel through a further development of the training program 24, 25; Avoid the reimdulation, which is characterized by the fact that r24 the series connection of the control paths is parallel to the lead capacitor via a resistor, a transistor ρ IO and a thyristor /> 9. second lead capacitor is connected in parallel, the collector of the transistor ρ 10 is connected to the complementary transistor in the discharge circuit as stands r6 and r8 with the positive terminal P of one of the lead capacitors, a resistor is connected in front of a DC voltage source, not shown, and d? < \ the second lead capacitor, This DC voltage source has a between .ier discharge circuit and the ÄC circuit are matched to each other, the terminal P and a negative terminal N , that the second lead to the tap M and supplies between P and M capacitor to at the end of the separator current lower 30 and W each have a voltage of 24 volts. Between the bend discharges and that the resistance is measured. the tap M and the terminal N are in series Ui, so that the control voltage on the second lead circuit, a first lead capacitor c 4, pin capacitor rises after its discharging so that a resistor r20, a diode «10, the transmitter collector fast, A transistor / 8 and a diode η 13 rise without overshoots. The separator voltage takes place. 35 The base of the transistor p8 is the anode of the Thy-

The invention is connected to the drawing in more detail ristors p9, the cathode of which is connected to the

explained. It shows terminal N is located.

F i g. 1 shows the basic circuit diagram of an embodiment. The emitter example is parallel to r20, «10, /> 8 and« 13 the invention and collector path of a transistor / ?? in series with

F i g. 2 Details of the in F i g. 1 with St denotes 40 a resistor rl8. The Dasis of this transistor is

Neten control unit. to one formed from resistors r 16 and r17

In F 2 g. 1, the power circuit is only symbo- and between terminal M and the emitter of the

illustrated. It consists of a voltage divider with F denoted- transistor ρ 8 connected-

Neten electrostatic precipitator, which has a rectifier C sen. The transistor / »? holds the one flowing over him

to the secondary winding of a high-voltage trans- 45 charging current essentially on a through rl7 and /

forniators T is connected. The primary winding or rl8 easily adjustable value within wide limits

this high voltage transformer is constant over one of the.

Improvement of the form factor serving smoothing The first lead capacitor c4 is via a

throttle D, a thyristor resistor rl5 connected in anti-parallel, a second lead capacitor cS

working actuator S and a current transformer W 50 connected in parallel, from which the voltage Uma for the

to terminal U of a single or multi-phase tax rate / is tapped, but its capacity

AC voltage network connected. only a fraction of that of the first Führurig capacitor

The control pulses for the thyristors of the Stell- c4 is.

element S are supplied by a control set /, to which to discharge the lead capacitors to synchronize the AC voltage of the 55 is dependent on the separator current is the first AC voltage network and on the other hand via a lead capacitorc4 via a resistor, the terminal A a the phase position of the control pulses rela- emitter-collector- Path of a transistor p4 connected in parallel to the AC voltage determining control, the base of which is fed to the voltage Uma via the resistor r6. The output of the collector of the transistor / »10 and via the cons control pulses can stand regardless of the size 60.-8 is connected to the terminal P.,
of the control voltage by means of a terminal L to discharge the lead capacitors when the extinguishing signal is supplied. A transistor extinguishing signal is always provided by the control unit St , the emitter-collector path of which is produced via a flashover in the separator, if a breakdown or short circuit in the changeable resistor r 13 occurred to the first guide separator. A possible capacitor c4 at the start of operation and a resistor rl4 and special case will be explained later. a valve «9 to the second lead capacitor c5

The control voltage Uma is connected in parallel by the control unit. The time constant from management

Sl supplied and is dependent on a capacitor CS and resistor rl4, $ 0 is small

selects that the lead capacitor c 5 at a voltage divider is dimensioned so that the at the

By controlling the transistor p5 as a result of a down control path of the transistor p6 when the tran-

Scheiderüberlagcs practically completely discharged sistor p2 lying voltage to control the

will; on the other hand, the charging time transistorp6 is sufficient; p5 is then blocked. the

constant, determined by resistor rl5 and Kon- 5 base of transistor p6 is also via a diode

capacitor r5, so small that the voltage at the second «8 and the resistor r8 at terminal P

Lead capacitor r5 after the elimination of an excess. The resistances rS and r6 are so

shock and blocking of the transistor p5 extremely measure that at the connection point of these resistors

quickly borrowed to the tension of the first guide at the drawn position of a toggle switch s or

capacitor c4 increases. io when the transistor ρ 10 is switched on (overcurrent or

The discharge of the first leading capacitor r4 rated current) has such a potential that diode

is blocked in the event of a rollover and control of the Tran- / i8; w8 is conductive when s is switched and

sistorsp5, on the other hand, is much slower. ρ 10 is blocked.

agrees with the size of the resistor rl3, before To detect a metallic short circuit in itself, so that the voltage on the lead capacitor ts the electrostatic precipitator is a relay equipped with a working c4 after a flashover only for a slight contact /? with a diode η 14 at rl3 adjustable percentage is lower than before it is connected in parallel. The relay is flashing over the emitter deton. Collector path of a transistor p3, a diode »5 To detect a precipitator flashover, the and the changeover switch between terminals P and already in FIG. 1 shown glow lamp / connected as ao N. The base of the transistor p3 is arranged over a photo element / that the resistors rS and rl and a diode «7 are connected to the light-sensitive area of the photo element of the light collector of the transistor p2; p3 receives radiation from the glow lamp / is exposed. The photo element / thus with the transistor p2 blocked (normal operation) is a through-flow current via a diode / il so the base-emitter. Connected in parallel between the resistors path of a transistor ρ 1 that the as rS and rl and the emitter of the transistor p3 is a capacitor c 2 with a relatively large capacitance that occurs when the photo element is irradiated and the voltage can pass through the transistor pi. Its size, together with the resistor rS, determines the connection point of the photo element / and diode n \ time between a short circuit in the remote via the contradiction rl at the terminal P. Scheider (through-control of the transistor p2) and the

The transistor ρ 1 forms together with a tran- 30 falling of the relay R elapses, sistor p2, resistors rl, r3, r4 and a capacitor. The collector of transistor p8 is a monostable multivibrator via a diode salor rl. When the glow / ill and a resistor r21 with the collector of the lamp / lights up - so with normal separator transistor ρ 2 and another diode η 12 and operated -, transistor ρ 1 is turned on and Tran- a resistor r22 with the Emitter of the transistor sistor p2 blocked. In the event of a flashover in the separator 35 p3 connected. The emitter of the transistor p3 is extinguished, the glow lamp goes out /, and transistor ρ 1 also goes into the blocking state via a resistor r23 at the base of which the transistor ρ8 is switched on. Resistor r21 is roughly the same as transistor p2. In the process, the same as r4 discharges, so that when the transistor ρ2 is blocked, the capacitor rl previously charged via r4, r2 and pl, but when the transistor p8 is blown at the collector via pl, «3, nl and r2, and thus holds - without back-40 from p2 the potential of terminal M is approximately. The view of the operating state of the separator - which is caused by a charging of the capacitor r3 when the transistor ρ 1 is blocked and thus the transistor ρ 8 is turned on (during the chip control of the transistor p2 for a timer run-up on the separator after switching on) This constant loading crisis prevents a certain time. This upright due to the waviness of the separator. 45 voltage caused during the run-up process do not bring about a drop in voltage. p6 is connected to terminal N. In addition, there is a control current in parallel via r8 and / 18, provided that s is around · r9 and r3 is a resistance r10. When the Tran- 50 is locked (operation) and pO is locked. sistor p2 (normal operation), the capacitor r3 is set up. The resistances of the relay R and the resistors have a voltage with the specified polarity r22 are dimensioned so that the emitter of the transistor is charged. When the """transistor p2 is switched through, p3 is so negative during this operating state that this capacitor can block via p2, the diode; i3, diode« 5 and the transistor p3 controls the F.milter-base path of the transistor p5 and the 55 stays.

Resistor r9 discharged, so that the transistor p5 The changeover switch s is used to ensure a defi

always at the same time with transistor p2 through-controlled initial state when commissioning de

will. The F.ntladcsUomkicis of the capacitor r3 is annex. In the switching position shown is di

preferably dimensioned so that the control of the base of the transistor p8 via r23 and diode n5 mi

TransistcMspS is not connected to terminal N before the end of the back-tilt line 60, so that this transistor is peed

the monostable multivibrator ends. on the other hand, that of the first sensing capacitor is c

In parallel to the control path of the pnp transistor p5, transistor p4 connected in parallel is turned on, d

is the Sieuci path of an npn-1transislorsp6, whose base is via resistor r6 and diode / 16 ebet

[ ^: miltcr-Kollcklor-Sircckc via a resistor rl2 if connected to terminal N. Since at the Elektn

/ wipe the terminals / 'and Λ / is connected. 65 separator is still no voltage, are also d

Dir AusRiinpsklcmmc /. is durchgestcucrt with the collector of these transistors p2 and p5; p6 is som

Transistor connected. locked, unt? at terminal /, there is an extinguishing signal. The fill

!) he made the reflection stood rA, rlO and r 19 formed tu ·: gskondcnsatorcn are discharged.

In addition, the changeover switch j in the drawing r 18 is charged with a constant current

neten position a quenching of the thyristor? p9 after the lying in the control circuit of the transistor p7

Shutdown of the system. Diode «13 is the charging of the lead condenser To start up the system, the Umtoren is practically independent of the surrounding terri-

switch s placed in the second switch position, at which temperature 5, which is particularly important with very large Zeilkonstanle

the cathodes of diodes «5 and« 6 with terminal M is of considerable importance. By the way, is the

are connected. As a result, the connection control circuit of the transistor ρ 7 is relatively low.

point of resistors r6 and r8 so positive that tran- ohmig, so that it is easily possible to

sistorp4 blocks and p6 in the conductive state over-changeable resistance τ Yl far away from the rest

goes. This means that there is no clear signal at terminal L, to arrange the system in a control panel,

so that the control rate / (Fig. 1) control pulses to the if during operation of the separator flow

Actuator S emits, the phase position of this exceeding the nominal value, the transistor ρ becomes 10 Control pulses from the voltage Uuα to the second and with it transistor p4 temporarily passed Lead capacitor c 5 is dependent. controls so that the lead capacitors c 4 and rS In addition, the transistor p8 is somewhat discharged via the tran-

sistorp3 and resistor r23 result in a turn-on separator voltage; the exit goes

electricity. Therefore, the lead capacitors are charged back below the nominal value, and

c4 and f5 via r20 "" 10, p8 and "13 on a span - the transistors ρ 10 and p4 go back into the

voltage with the polarity indicated in the figure; Lock state over. Then the tension on the increases

the charging time constant has a very low value, including lead capacitors and again in the separator

since the tension on the lead condenser slowly increases linearly. In this way, the parting

•• sator c5 dependent separator voltage the current as long as possible without voltage-dependent low-

soon after the system is switched on, the lowering is limited to the nominal value, such as no excess

should reach fractional value. shock occurs in the separator.

As soon as transistor p8 after switching the as. When a flashover in the separator s conducts without a return switch, the tran-mouth r2l and the diodes «11 and« 13 also flow through the resistors, a current that flows through the sistorp5 Discharge of the capacitor c3 in the aforementioned dimensioning of the resistors through-controlled and thereby the first hührungskonden has the consequence that the potential at the collector of the satorc4überrl3um a certain, relatively transistor p2 regardless of the operating state 30 small amount and the second condenser c5 of the separator and the Switch position of the mono via rl4 and «9 almost completely discharged. Unstable flip-flop approximately the potential of terminal M this is compulsory when p5 is controlled. The transistor p3, however, still receives transistor p6 in the off-state, via «7, rl, rS, emitter-base path, r22,« 12, so that the output of control pulses to the control emitter controller. Line from p8 and «13 a 35 member through the occurrence of a Löschsitriales on the control current, since the potential of the emitter of p3 at terminal L is suppressed. At the end of the return of the previously mentioned dimensioning of relay R and the breakover time of the monostable multivibrator, transistor resistor r22 is more negative than the potential of p5 again, and the second lead capacitor c5, terminal M; the relay R therefore remains energized. charges at a relatively high speed

During the rapid charging of the lead capacitor 40 to the voltage of the first lead capacitor c4

capacitors via the conductive transistor p8 receives the on; accordingly, the deposition rate increases

Transistorpo apply a through-flow current via the resistance voltage. because transistor p6 when the

stood r8 and diode «8, so that no transistor p5 was conductive at terminal L and thus no erasure

Delete signal is present; the tax rate / (Fig. 1) therefore gives more signal is available. The charging speed Control pulses to the actuator S , the phase 45 speed of the lead capacitor c 5 is the Anlaj

position these control pulses from the voltage Uma to adapted so that the filter voltage as fast as

the second lead capacitor cS is dependent. possible without overshooting at first

With the rise of the voltage at cS and the lead capacitor c4 the certain value increases,

corresponding increase in separator voltage During the exponential charging of the lead

If the separator current also increases, and thus the condenser capacitors on the 50 (through control of p8), the

Resistance r26 tapped voltage too. With a transistor p5 no control current through the resistor

certain value of the voltage at r26 (obtained at nominal rl9. This is achieved by the

value of the separating current), the Zener diode η 14 transistor p6 becomes a through-flow current via r8 and λ8

current-permeable and transistor ρ 10 and thyristor p9 receives, so that the at the base-Emitler path of the

steered through. 55 transistor p6 flows through the conductive thyristor ρ9 as a spernrorpan-

from then on the current of the relay R (via p3 and resistance on the control path of the transistor p5 is applied

stand r23); In addition, the transistor p8 goes into the control current for p6 via rS and «8 is omitted.

Speirstatus over, as its control path through p9 when the separator current at the end of the run-up time

is short-circuited: This means that the exponential has reached the nominal current and thus transistor ρ 10

Fast charging of the lead capacitors is controlled via p8 60. If at this point in the

and furthermore the blocking of the output signal of the separator no flashover present ad thus

monostable multivibrator ended via r2I and nil. Transistorp2 of the monostable Kippsi-if «· blocked

The thyristor p9 remains until the is switched back, p6 receives a through-flow current through M and r 10. Changeover switch s in the switching position shown, ie it is, however, when the transistor responds for the first time

until the system is switched off, regardless of the 65 ρ 10 after commissioning the system in the separator

Control state of the transistor ρ JO turned on. The flashover or an electric arc exist and hence Lead capacitors can therefore select the transistor p2 durchgesleucrt. then crhal »transistor Operation only via the transistor / »7 and counterp6 neither via contradictions r4 and r10 nor via

Resistor r8 and diode / 18 a control current so that this transistor blocks and a clear signal to block the control pulses for the actuator 5 occurs at the terminal /. At the same time, transistor pS receives a through-flow current via resistor r 19, so that the discharge of the second lead capacitor c5 is also ensured; a through-control of this transistor p5 by the capacitor c3 via the transistor pt , on the other hand, would not be possible at the end of the exponential charging of the lead capacitors, since the capacitor c3 could not yet be charged due to the control of the transistor /> 8. While in the time after the exponential rise

10

charge of the lead capacitors the output of a quenching signal and the discharge of both lead capacitors through transistor p5 takes place regardless of the separator current at each flashover in the separator, when the exponential charging is terminated, a voltage drop through p5 and the output of a delete signal is only initiated if a flashover or an arc is present in the separator and the separator current has reached or exceeded the ίο nominal value.

The invention also applies to systems for controlling an electron or ion beam for material processing applicable.

1 sheet of drawings

Claims (4)

1 2 is that the control voltage on the second guide claims: capacitor (c5) rises after its discharge so that a rapid, overshoot-free rise 1. Arrangement for the automatic control of the separator voltage.
Separator voltage in an electrostatic precipitator, p with an actuator in the feed circuit of the electrical separate that from a tax rate a manipulated variable receives, which trains from one of the tax rate- The invention relates to an arrangement for self-guided Control voltage from a control unit. Control of the separator voltage in one depends, in turn, on a DC electrostatic precipitator, with an actuator in the feed circuit connected to the charging circuit and the control voltage of the electrostatic precipitator, which is supplied by a control set contains the determining lead capacitor, dtr receives the manipulated variable that is assigned to the tax rate the control voltage of a control unit depends on the separator voltage, has controlled discharge circuit, which in turn indicates a DC charging circuit, that the control pulses 15 closed and determining the Steuerspannunp supplying tax rate (/) of a thyristor actuator contains lead capacitor, which one of the des (S) depending on the occurrence of a separator voltage dependent controlled discharge blocking signal having at the emitter of a first transistor circuit. (p6) the control unit can terminate its control process. As an actuator, a variable transformer, ad "and the actuator (S) blocks, including the base of the ao transducer, a thyristor-operating actuator first transistor (p6) together with the base or a The supply of a voltage source in the discharge circuit of the lead capacitor can be configured in one or more phases (f 4), complementary to n transistor (p5). A handle of a first voltage divider (r4, for example from the French patent specification / -10, r19) is connected, so that a current-blocking separator, also called separator voltage, of the type mentioned above, is normally an electrostatic precipitator, also known as an electrostatic precipitator known, in which controlled third transistor 0> 2) a transductor is arranged as an actuator in the separator current linest'.n as the first transistor (p6) emitter circuit, which is controlled by thyristors on the side with the emitter "and on the collector side Investigations on such systems have shown a C'-Xreis (r9, r10, c3) with the tap of 30 that after each flashover in the electrical first voltage divider (rf r10, r \ 9) the separator connected is temporarily much higher, that furthermore a current flows through an operating switch (s) u <id that thus higher maintenance costs operationally with the emitter of the complement and a lower service life of the Llektroabs Eitischen transistor (p5) connected second voltage are connected. The temporarily increased voltage divider (r6, r &) with its tapping via a separator current is due to the fact that the diode (/ 18) is connected to the tap in the forward direction with control devices and actuators with time constants of the first voltage divider (r4, r 10, r 19). th are affected and therefore the separator voltage is the. not immediately after a rollover occurs 2. Arrangement according to claim 1, can thereby be reduced in the electrostatic precipitator,
indicates that the third transistor (p2) of 40 example, from the German Auslegeschrift a fourth transistor (p \) a monostable 1,257,115 .'st in electrostatic precipitators with Stell'ransfor-flop (pi, pi, rl, r4, el, nl, η H) , the shutdown time of the / JC circuit (c3, r9, r 110) circuit of the entire system by means of relays is known to extinguish the arc. One is adapted. such shutdown is due to the variable transformer 3. Arrangement according to claim 1, thereby gated 45 and the slow switching of the relay only as indicates that the second voltage divider can be used occasionally as an emergency measure. (r6, rS) via a diode (n6) with the operating The BBC news, March 1968, is on page 153 switch (s) is connected, which can be seen in the rest position, for example, that with thyristor control via a fifth transistor (p 10) guided links for electrostatic precipitators a current flow prevention of the voltage divider bridged with the one 5 ° break in about half a period after output of the DC voltage pole (/ V) and that a blocking signal is possible. This liter of a limit value transmitter (g, rl4, rlS, r26, / rl4) does not provide any details about tax rates and normally blocked fifth transistor (p 10) control units for such actuators.
when a limit value of the separation is exceeded, the object of the invention is to control the front flow so that it is permeable. 55 transient occurrence of an increased current after 4. to avoid arrangement according to one or more of a rollover,
According to the invention, this object is genet in that the lead capacitor (c4) solves that the control pulse supplying control resistor resistor (rl5) a second lead capacitor of a thyristor actuator depending on the Auf- (cS) connected in parallel is that the kcmplemen- 60 occur a blocking signal at the emitter of a first tary transistor (pS) in the discharge circuit of both transistors of the control unit, its positioning capacitors precede a resistor (rI4) and the actuator blocks, for which the base of the is connected and that the second lead capacitor first transistor together with the base of a in the sator (c5), the discharge circuit (pS, rl4) and the discharge circuit of the lead capacitor lying ÄC circuit (r9, r10, c3) so matched 65 complementary transistor to a tap one is that the second guide capacitor (cS) is connected to the first voltage divider that one in normal operation up to the end of the separator current interruption, current-blocking, separator voltage discharges and that the resistor (r 15) is dimensioned controlled third transistor of the same conductivity type