DE3118542A1 - Electrostatic gas purification appliance and method for varying the operating high voltage of this appliance - Google Patents

Abstract

In an electrostatic gas purification appliance and in a method for varying the operating high voltage of this appliance a voltage setter (voltage controller) is provided which generates a variable output voltage from an operating alternating-current voltage. This variable output voltage controls a high-voltage converter which supplies a high voltage to a gas purifier. The variable output voltage is controlled by a control signal of a regulating device. The regulating device brings about a reduction in the control signal of the high-voltage converter, when the load of the latter exceeds a predetermined limit value during a corresponding limit time interval. After this limited time interval, the regulating device brings about a rapid run-up of the high-voltage converter, preferably by the next half-wave (half-cycle) of the operating alternating-current voltage, whose polarity is opposite to that at the beginning of the limited time interval. Thus stable operation is achieved very rapidly. <IMAGE>

Description

Electrostatic gas cleaning device and

Method of changing the operating high voltage of this device With an electrostatic exhaust gas cleaner, a high voltage is used for ionization and deflection of pollutants from exhaust gases is used. Known electrostatic Gas cleaning devices control the level of high voltage by making them so set that sparks are generated with a predetermined repetition frequency. There If sparks can be easily determined, this spark repetition frequency control easily performed, but only with high power losses and low reliability. Due to the repeated sparking, these devices cause significant Load on the power supply device and its transformer-rectifier arrangement.

In addition, the manifold plates and emission wires become the gas cleaning device constantly eroded.

Known electrostatic gas cleaning devices operate in dependence excessive sparking or arcing occurring during a typical Operation occurs irregularly, a rapid shutdown and subsequent gradual renewed high voltage control. This gradual or 'slow' or "soft ramp-up avoids excessively high initial currents and voltages. This excessive initial loads are the result of strong sparks or arcing, the magnetic devices in the high-voltage power supply device in the Drive saturation.

When the core of a high voltage transformer is saturated, it can the renewed application of the operating voltage, regardless of its polarity, to a further saturation and therefore to a very low-resistance load circuit to lead, that loads the network with an excessive current. on the other hand can also be a choke coil located in the primary circuit of the high-voltage transformer be driven into saturation. This saturated choke coil then does nothing sufficient current limitation more so that the transformer is overloaded and emits too high a voltage on the secondary side.

This can lead to a self-destructive runaway in which a spark creates a high voltage surge, which in turn causes a spark. The mentioned devices with "slow" ramp-up take this into account Behavior by gradually increasing the modulation of the magnetic circuits, so that their magnetic cores can desaturate again and on a middle, symmetrical hysteresis loop can be operated.

This delayed restoration of the full power of the high voltage supply device however, it has the disadvantage that the charge inside the gas cleaning device decreases.

On the other hand, sparking means high energy losses, but it is initially localized. Adjacent gas cleaner parts can therefore initially retained their charge because of the effective series resistance and the Inductance between the gas components is not negligible. Much more These impedances predominate when a spark has a localized low resistance Forms current path. Hence, it joins sparks whose duration is generally short is (one to four milliseconds), a period of time in which the charge is in advantageous Way can redistribute. A localized discharge can therefore occur Immediately reconnect a supplement to the load and connect it at a lower height.

However, since the operating voltage is longer in known devices when the mentioned period of time is switched off, the remaining charge can disappear completely.

If the gas cleaning device can be discharged so far, is they are no longer able to hold onto the accumulated dust. Rather, it will he repelled again. The repelled dust then increases the likelihood that another spark occurs, which in turn can lead to a runaway.

Once the gas cleaning device has discharged so far, make it the limited rated current of the device, the capacity of the gas purifier and the inductance of the series reactor impossible to use the gas purifier recharge immediately. These known devices are therefore unnecessary a lot of time to recharge unnecessarily discharged gas purifiers. This unproductive Delay time stands in the way of effective voltage regulation. In contrast is achieved by a rapid restoration of operational performance, as in accordance with the invention is more likely to achieve the theoretically maximum possible performance.

The destructive effect of a surge process can be illustrated by assuming that a spark is followed by a time period DTa in which the power (voltage) is removed. It is then assumed that the charging current increases linearly during the time DTb and then maintains a constant maximum value Im. (The following calculation can easily be transferred to the other exciting functions, such as a section-wise linear rise curve with an initially high and then low slope.) Since the energy output is equal to the effective resistance R multiplied by the time integral of the square of the current, results for the total energy: where t = 0 is selected as the point in time at which the charging current begins.

By solving for t = Tf - DTa, where Tf is the period after which the process is repeated, one obtains the energy per period: The maximum energy is then DTa = DTb = O. This results in the theoretically maximum power that can be delivered: Im2R. If you ignore the rise time, which corresponds to the time DTb, the result is a square wave as the charging current curve, so that the power then output would be equal to the maximum theoretical power multiplied by the duty cycle DTa / Tf. This pulse duty factor or working cycle can approach its maximum value of one if the time between the sparks is selected as long as desired or the time after a spark, during which the power is reduced, is selected as short as desired. In the known devices, by alternately discharging and charging the gas cleaner, fine electrical changes that are required for regulating the high voltage are effectively covered. Since the jumps caused by the spark formation and the input currents due to the recharging are so large, these known control devices are designed so that they respond to an easily detectable event: the spark formation itself. Although it would be possible to increase the control signal of a high voltage supply device only gradually In order to detect subtle electrical changes, this would result in the high voltage decreasing to too low a value.

The invention is based on the object of an electrostatic gas cleaning device and to specify a method for changing the operating high voltage of this device, in which a stable operation in a simple manner with low power dissipation long service life is achieved.

Starting with an electrostatic gas cleaning device a voltage regulator that converts an operating AC voltage into an output voltage generated, which changes depending on a control signal, and with a high-voltage device, this object is achieved according to the invention by a high-voltage converter device, the. is acted upon by the voltage regulator and a variable high voltage generated, and a control device for generating and changing the control signal, wherein the control device can be operated in such a way that it controls the e High-voltage converter device depending on that suppresses its load exceeds a predetermined limit value during a predetermined limit interval, and after this limit interval the activation of the high-voltage converter device by the next half-wave of the operating AC voltage, the polarity of which is opposite to which is at the beginning of the limit interval, so that the device is quickly stabilized again.

A method according to the invention for changing the voltage of a high-voltage converter device an electrostatic gas cleaning device generated high voltage, wherein the Converter device is acted upon by a voltage regulator, the output variable of which changes as a function of a control signal and wherein the converter device is connected to a conductive element which is conductive to an extent that corresponds to the modulation of the converter device for generating the high voltage, consists of initially measuring the voltage on the conductive element, that then the control signal is changed in a direction in which the modulation the high-voltage converter device increases, that then the voltage on the conductive Element after a predetermined time interval has elapsed after the initial measurement is measured again and that the control signal is then changed in one direction, in which the output variable of the actuator as a function of a predetermined change the voltage on the conductive element is changed over the predetermined interval.

Further developments are characterized in the subclaims.

In this training or method, performance is preferred reduced as much as possible. After that, the performance is back very quickly up to in the proximity of the value preceding sparking is controlled upwards. Preferably the power ramp-up is timed so that when a spark occurs for saturation of a magnetic component of the high-voltage supply device has led, this component is immediately driven in the opposite direction and thus is desaturated.

In addition, in the present invention, the visual value is preferably used of the control signal supplied to the high-voltage converter device with a preceding one Value compared. In this way, electrical disturbances are detected which one Sparking. The device can therefore prevent itself from occurring adjust a spark to avoid it. A device according to the invention is therefore designed so that no sparks occur during operation. Preferably the adjustments made to avoid a spark are proportionate small, so that they do not substantially affect the steady state. These Stability facilitates constant monitoring of the impending sparking. With this method, the high voltage can be continuous up to one sufficient high value can be driven up without the risk of spark formation occurring. The active power available in the gas cleaner can be increased by up to 200%.

In a preferred embodiment, the current conduction angle is Controllable silicon rectifier connected in antiparallel with a predetermined Speed increases, resulting in a rapid but controlled increase in output voltage of the high-voltage transformer. The speed of enlargement of the current flow angle can be achieved by feedback a measurement signal for Control device can be influenced, the voltage drop across a linear inductive Current limiting resistor in the primary circuit corresponds. This signal represents the speed the power consumption by the gas cleaner itself. The control device can furthermore in each operating half-wave as a function of measured variables, such as the voltages and currents on the transformer primary or secondary side (i.e. occur in the gas cleaner). Here, the device can also be a device have to store these measured quantities in order to match them with the measured quantities from the next or to compare a later half-wave. That way are when you occur of a spark always the latest measured values of all measurable electrical parameters available for evaluation.

By means of the device according to the invention, a very Carry out a quick comparison, e.g. between the measured value of the secondary voltage and / or the secondary current at which the spark occurred and and the thyristor current conduction angle, which is required to effect this measurement. More information that can be stored, for example: Whether the current flow angle of the controllable Rectifier or

Thyristor increased or decreased shortly before the spark occurred has been, the current conduction angle itself, the secondary voltage and / or the secondary current, the voltage drop across the linear measuring resistor or any other to be taken into account characteristic quantity that is present shortly before spark formation. This means, a new "local time average" can be formed before the control device intervenes again. Since, according to the method according to the invention, a renewed upward control the power follows, the control device can set a new thyristor current conduction angle set so that now secondary voltages immediately (within one or two half-waves) and / or currents are set which are immediately below those at which the first spark occurred If a spark is generated again, a new local Averaged and the process repeated will.

In this way, the secondary voltage and / or the secondary current reduced until when or shortly after the renewed upward steering (or switching on again) no more spark occurs.

By reducing the thyristor current conduction angle by small amounts (which are less than an electrical degree) it is possible to operate for long periods Time (several dozen half-waves) immediately below the voltage and / or Maintain current values at which a spark has previously occurred.

More importantly, however, the device should become stable so quickly Operation that sparking conditions can be determined very easily can.

If there is no sign of impending sparking from a Monitoring is determined over several half waves, the thyristor current conduction angle can be enlarged, but again only by a small amount and in one single amount Step so that the steady state is disturbed as little as possible. The control device continues with the formation of local averages, and at a certain current flow angle faults indicating the impending spark formation can then be determined will. At this point it is up to the designer, like the control device should intervene. An operation during several half waves indicates that a continuation operation with the instantaneous voltage and / or current values leads to spark formation would lead, so that the obvious intervention would be the thyristor current conduction angle to decrease by an amount that depends on the amplitude (or distribution) of the upcoming Disruption depends. After that, data is again collected in order to check whether and if so, if so how the disturbance was affected and then a new decision is made. So the operation continues and the thyristor current conduction angle normally by the control device, whenever possible, increased by the maximum field voltage and to adjust the maximum ionization current in a way that is constantly maintained by the collected (measured) data is changed so that the performance is rapidly diminished by a very small amount when an imminent one Sparking condition occurs.

The mentioned comparison measurement is preferably carried out periodically, in order to eliminate periodic influences that change direction Operating current (an operating alternating current).

Furthermore, the point in time at which a measurement is carried out can be as follows be chosen so that it falls during the time when the probability is greatest is that the change in a current represents the impending sparking. So is the probability of sparking in a predetermined time interval after an intervention by the voltage regulator or - with alternating current - with a predetermined one Phase angle greatest.

Then the control signal that controls the modulation of the high-voltage converter determined, repeatedly increased in stages. This process can be reversed, when the high voltage drops at the onset of a back corona discharge.

The invention and its developments are described below with reference to the Drawing of preferred embodiments described in more detail. They show: FIG. 1 a block diagram of a gas cleaning device with one designed according to the invention High-voltage device, FIG. 2 is a circuit diagram of an absolute value formation separating stage the device according to Fig. 1, Fig. 3 part of a circuit diagram of a voltage regulator, which is used in the apparatus of Fig. 1, Fig. 4 is a block diagram of a Triggerable (triggered) monitoring device, which is in the device according to Fig. 1 is used, 5 shows a block diagram of a microcomputer, which is used in the apparatus of FIG. 1, FIG. 6 is a block diagram of FIG Operating devices and display devices that can be used with the device according to Fig. 1, FIG. 7 shows a block diagram of the actuating device and interface device between voltage regulator and control device, which in the device according to Fig. 1 are used; occur according to FIGS. 1 to 7 and FIG. 9 is a flow chart for explaining the Operation of the devices according to FIGS. 1 to 7.

According to Fig. 1 lies between an input line P2 and an output line P4 a voltage regulator 10. This has two antiparallel-connected between lines P2 and P4 Thyristors Q1 and Q2, so that it can carry alternating current. By controlling the ignition timing or the firing angle of the thyristors Q1 and Q2 can adjust their current flow accordingly being controlled. Although a thyristor controller is shown, another can also be used Controller can be used, e.g. a saturable choke coil (transducer).

The actuator 10 acts on a high-voltage converter device in Form of a transformer-rectifier arrangement Ti, 18.

Between input terminals 12 for the primary AC operating voltage lie ekn conductive element in the form of a current limiting inductor 16, the Actuator 10 and the primary winding 14 of the high voltage transformer T1 in series. The transformer T1 and a two-way bridge rectifier form the high-voltage converter 18 with diodes CR1, CR2, CR3 and CR4. The anode of the diode CR1 and the cathode of the Diodes CR2 are connected to one terminal of the secondary winding 20, the other Connection to the cathode of the diode CR3 and the anode of the diode CR4 connected is. The cathodes of the diodes CR1 and CR4 are through ohmic resistors R4 and R6 each connected to ground. The anodes of the diodes CR2 and CR3 are with connected to the junction of surge limiting reactors L2 and L4. Of the Transformer T1 has a high transmission ratio and generates a negative, high DC voltage at the connection point of the inductors L2 and L4.

Although a choke coil is shown as conductive element 16, Another component, e.g. an ohmic resistor, can also be used. The use of an inductive element 16, however, has the advantage that it is jump-like Responds to changes or impulses that indicate the impending spark formation. However, a high sensitivity to sudden transitions can also be achieved Use a series-connected ohmic resistor to achieve its voltage drop is differentiated. Although the element 16 to the primary winding of the transformer T1 is shown connected in series, it can also be connected in other places be that it depends on the modulation of the transformer T1 and the Make diodes CR1, CR2, CR3 and CR4 conductive or current-carrying. So could a Voltage divider between the connection point of the diodes CR2 and CR3 on the one hand and ground on the other hand are switched in order to control the high-voltage converter to eat.

The connections of the choke coils that are not directly connected to one another L2 and L4 are separated with high voltage electrodes 22 and 24 from electrostatic ones, respectively Gas purifiers 26 and 28 connected. The gas cleaners 26 and 28 are known per se Formed way and are located in the exhaust duct of a machine or a process. By means of correspondingly high electric fields in the gas cleaners 26 and 28 the particles in the exhaust are ionized and deflected so that it is cleaned on the element 16 is the primary winding 30 of a transformer T2, its secondary winding 32 lies between ground and the input of an absolute value formation separator ABS1. The absolute value formation -Isolation stage ABS1 (whose structure is still in each) generates a single-pole signal with an amount equal to is proportional to the absolute value of its input signal.

One inductive with the one between the input 12 and the element 16 Line-coupled current transformer T3 generates a signal that is the primary current of transformer T1 is proportional. The current transformer T3 is on the secondary side via an isolating transformer T4 at the input of an absolute value formation s isolating stage ABS2. The ABS2 separation stage for absolute values has the same structure as the separation stage ABS1. The primary windings of transformers T1 and T5 are parallel. The secondary winding of the transformer T4 is at the input of an absolute value separation stage ABS3, the structure of which is the same as that of the separation stage ABS1.

The separation stages ABS2 and ABS3 are controlled by voltages, the respective the primary current and the primary voltage of the high voltage transformer T1 are proportional. The secondary current of the transformer Tl flows in one Half-wave through resistor R4 and in the following through resistor R6. This Secondary current signal is transmitted through non-inverting isolation amplifiers 34 and 36, each with the non-earthed (grounded) connections. of resistances R4 and R6 are connected.

Two voltage dividers are provided as the high-voltage measuring device, although a Hall generator or other device is also used instead can be. One voltage divider is located between the high-voltage electrode 22 and ground and consists of two ohmic resistors R8 connected in series and R70. The second voltage divider also consists of two series-connected ohmic resistors R12 and R14 between the high voltage electrode 24 and Mass lying. The connection point of the resistors R8 and R? O is with the input a reversing isolation amplifier 38 connected, so that this one of the operating voltage of the gas cleaner 26 proportional voltage is supplied. In a similar way it is a reversing isolation amplifier at the junction of resistors R12 and R14 40 connected so that this one of the operating voltage of the gas cleaner 28 proportional Voltage is supplied.

In many applications it is beneficial to use the one just described The device according to FIG. 1 is to be arranged in the vicinity of the gas cleaners 26 and 28. Frequently such a device is expedient in the vicinity of one or more chimneys housed. As the other accessories of the facility are arranged in one place that is easily accessible to an operator is the appropriate one Separation point represented by a dashed separating line RF.

The outputs of the isolators ABS2, AB53, 34, 36, 38 and 40 are respectively with interface inputs IN2, IN3, IN4, IN5, IN6 and IN7 of an auxiliary device 42 connected. The output of the isolating stage ABS1 is connected to a signal conditioning circuit 43 connected, the output of which is connected to the input 1N1 of the auxiliary device 42 is. The circuit 43 is preferably a low-pass filter. Instead of this however, an integrator can also be used. By the fact that the secondary facility 42, seven different input signals are supplied in this way they do provide detailed information about the operating behavior of the gas cleaner, however, a different number of input signals can also be used in other designs be provided. The auxiliary device 42 forms part of a control device with a triggerable or triggered (described in more detail below) Monitoring device that is acted upon via input IN1. The control device also contains a microcomputer COM, the circuit details of which are given below to be discribed. The connection between the secondary device 42 and the microcomputer COM is shown as a wide arrow to indicate more than one data link and to indicate the flow of information. The microcomputer COM scans repeatedly the inputs IN1 to IN7 off, so that they are in the time division multiplex method (one after the other) be connected to him. The microcomputer COM also supplies a control signal an auxiliary device 44. The auxiliary device 44 (to be described below) causes the control signal generated by the COM microcomputer to be converted into two Clock signals, which are fed to the controller 10 via lines 46, to adjust its current flow angle to control. the Ancillary device 44 forms a suitable interface between actuator 10 and control device 42. The auxiliary device 44 be designed differently if the actuator 10 instead of thyristors. a transducer or some other facility. By means of operating switches in an operating device CNL (to be described below) an operator can input run in the microcomputer COM. The microcomputer COM can be used by the operator Information by means of a display device DISP (which will be described below will show).

The COM microcomputer effects the overall control of the device, including clock and timing control and can be designed in various ways be. A microcomputer COM with a commercially available microprocessor is preferred.

Other embodiments are also possible. So can instead a digital an analog circuit arrangement can be used. For example Selectable storage capacitors can be charged to voltages that match the Show signals at inputs 1N1 to IN7 at different times. These Charging voltages can be selectively fed to a summing network to provide a control signal to create.

The microcomputer COM determines the repetition frequency and sequence in the respective input signals via the inputs IN1 to IN7 of the control device COM. In this embodiment, this repetition rate is normally twice as high as the mains frequency, but under certain circumstances it becomes significant chosen higher. It is also possible to choose other repetition frequencies that correspond to the respective Properties and operating behavior of the respective voltage regulator and gas cleaner are adapted.

The operation of the device according to FIG. 1 for the cases described that sparking is imminent, sparking has occurred. and a counter corona discharge is present.

It is assumed that the device of FIG. 1 is currently switched on has been and a relatively low voltage on the electrodes 22 and 24 trains. The microcomputer addresses the input in each half-wave 12 applied operating voltage the inputs IN6 and IN7 and takes the pending Data on. These data, including the voltages on electrodes 22 and 24, it receives after approximately 75% of a half-wave. This time allows the microcomputer COM provides a reliable estimate of what is currently present during the respective half-wave States and the control signal on line 46 before the next half-wave accordingly to adjust. The control signal is periodic for a while in each half-wave advanced in phase to increase the voltage on electrodes 22 and 24. The incremental increase in the control signal on line 46 may in some embodiments be slowed down while the voltages of electrodes 22 and 24 reach their setpoints approach. For example, assume that the voltage is sufficient to provide a condition train in which sparking is imminent. It is further assumed that the corona discharge in the gas cleaners 26 and 28 during the next half-wave expands and forms protrusions or "fingers". This expansion is the forerunner sparking - and results in a significant increase in the gas cleaner flow. This increase in the gas cleaner flow causes an increase in the voltage drop on the Element 16. Since the current disturbance caused by this corona discharge expansion Has strong high frequency components, the coil 16 is particularly sensitive thereon. Furthermore, since the corona expansion is likely to be in the last part of a half-wave of the operating AC voltage occurs at input 12, makes the fact that the microcomputer COM records the measured values during this time, he is particularly sensitive to this phenomenon.

After recording a measured value via input IN1 after expiry of about 75% of the current half-wave, the microcomputer COM compares the last one Measured value with a threshold value (of for example 2 volts). In the flow chart according to Fig. 9 is this Process shown in the form of several branches. At branch 200, the device waits for a phase signal to appear at terminal 72 (which will be described in more detail below) that the Indicates expiration of 75% of the half-wave. This is done at branch 202 via the The signal supplied to input 1N1 is stored, and the threshold value comparison is carried out in branch 204 carried out. If the threshold is exceeded, the control signal is decremented respectively.

as indicated in branch 206, namely by a factor of about 1. This decrement is chosen so that it matches the characteristic and response time of the controlled gas cleaner is adapted.

After this operation (or assuming that the branch 206 was skipped because the threshold value of branch 2Q4 was not exceeded was), the value measured last at input 1N1 becomes the value previously measured at input IN1 is subtracted, as shown in branch 208. This difference is compared with a preset limit value (e.g. 10 compared to, as shown in branch 210, and if the limit value is exceeded, the control signal is decremented (reduced) or otherwise incremented (increased). This decrease and increase is each in the branch 212 and 214 shown. The amount of reduction is chosen to be the Characteristic curve and response time of the gas cleaner is adapted. The amount of increase in branch 210 is less than the decrement in branch 206. This Relation ensures that if there is a decrease, its influence will not is offset by the increase in branch 214.

The consequence of the aforementioned steps is that when the element 16 (Fig. 1) indicates the impending spark formation, the control signal (line 46 in Fig. 1) is reduced and otherwise enlarged. The gas cleaners 26 and 28 applied high voltage therefore has a relatively high Value immediately below the value at which sparking occurs. In this embodiment, the control signal is changed by a fixed amount, however, in other exemplary embodiments, the amount of change can also be based on a Table, a formula or other measured variables can be selected.

As you can see, * the microcomputer COM (Fig. I) can open very quickly address the impending spark formation and immediately reduce the current flow angle-des Try actuator 10 before the sparks occur. In this embodiment the controller contains 10 thyristors, which are only activated at the end of a half-wave at the input 12 lying operating AC voltage are blocked. Therefore the microcomputer needs COM not to be addressed before this point in time. However, if high speed switch or a saturable inductor (transducer) is used, the controller can locked immediately to avoid sparking.

It has been described above how to avoid sparking. The following describes how the device works when it is very powerful Interference should nevertheless occur.

It is assumed that in the middle of a half-wave the one at the input 12 (Fig. 1) applied operating voltage the spark formation in the gas cleaner 26 begins. As a result, the voltage on the high-voltage electrode 22 suddenly drops åb.-Die relatively small voltage, which consequently occurs at the input 1N6, is supplied by the Microcomputer COM recorded shortly thereafter. The last value at IN1 becomes a half-wave with the previously determined value compared, and if it reaches a predetermined limit (e.g. 25 c), the control device COM speaks through to this emergency Lowering of the control signal on line 46 to a minimum value. This Feature is also in the flow chart shown according to Fig. 9, this shows that immediately after the operation of the branch previously described 212 or 214, the latest values of the high voltage, which are transmitted via the inputs IN16 and 1N6 should be stored in memory. Of these latest or most recent values becomes the corresponding one stored in the previous half-wave Deducted the high voltage value. If the differences are greater than or equal to zero there is no further adjustment of the control signal and the process is repeated in the manner described below If both differences are negative, what indicates a drop in high voltage becomes a comparison with a preset one Sparking limit run to determine if sparks have occurred. If the limit value has been exceeded, the following happens, as it does in the branch offices 220, 222, 224 and 226 of the flow chart (Fig. 9) is indicated: The control signal is reset to zero to lock actuator 10 (Fig. 1). When the thyristors of the actuator 10, however, are already conductive, they remain until the end of the relevant Half-wave of the operating AC voltage at the input 12 conductive, as already mentioned became. Since a spark seems to have started, the microcomputer begins COM to request data from inputs IN6 and IN7 with a relatively high repetition rate. This higher repetition frequency is important because the actuator 10 remains blocked for so long must, as the sparks occur. Furthermore, since the one required to ignite a spark Voltage significantly higher than that required to maintain the spark Voltage is extinguished - the spark does not go out until the electrode voltage is substantial has decreased. The voltages at the inputs IN6 and IN7 are therefore long monitored in "real-time operation" until they have fallen below a clear value which the spark extinction is ensured (Fig. 8C) .- The one for extinguishing a spark required time can be different for each spark. Although the tension is on the electrodes 22 and 24 usually in the last half each Half-wave of the operating AC voltage at the input to 2 12-decreases, this decrease can be inadequate. Furthermore, the capacity of the gas cleaners 26 and 28 can be so large that that the tension decreases only very slowly. For these reasons, the microcomputer locks COM the controller 10 as long as the voltage at the electrode 22 or 24 is too high is. As soon as it is no longer too high, the control signal is switched on again, but with a slightly smaller value (e.g. 0 to 4% lower) than the one it had in the half-wave in which a spark occurred. This way the probability becomes reduces the occurrence of the sparks again.

If the high voltages shortly after the start of a subsequent half-wave the operating AC voltage at input 12 drops below the extinction value, the operation indicated in branch 228 (FIG. 9) is in progress. Here is transmit the reactivated control signal and then to the beginning of the sequence of operations returned as indicated in branch 234. By switching it on again of the control signal is one of the thyristors of the controller 10 (Fig. 1) again in a Time (phase angle) conductive, which is determined by the control signal.

The sequence of operations described above with reference to FIG. 9 represents represents a program cycle of the microcomputer. The microcomputer therefore expects this next occurrence of a phase signal after 75% of the current one has elapsed Half-wave of the operating AC voltage present at the input 12, as indicated by the Branch 200 is indicated.

The sequence mentioned comprised an operating AC voltage period, in which sparking occurred and in which branch 222 (Fig. 9) took place branch 230 has been executed. The following is the mode of action for the Case will be described that no sparks occurred and instead a back corona discharge effect in the last 25% of the relevant half-wave of the operating AC voltage at the input 12 occurred.

The back corona discharge effect occurs when operating with relatively high voltage in an area where a gas purifier has negative resistance (a negative slope in the voltage-current characteristic). A company in such an area is inefficient and should be avoided.

After the microcomputer COM (Fig. 1) has determined that the decrease (the decrement3 of the remaining voltage measured value at the inputs IN6 and IN7 no spark formation indicates, the operation represented by branch 230 (FIG. 9) begins. This operation consists in checking for this moderate decrease in high voltage exceeds a threshold value (e.g. 5%) that has a back corona discharge effect indicates. If this corona discharge s limit value is exceeded, the control signal reduced (decremented) by a predetermined amount (e.g. 1 5 '), as shown in branch 232 is specified. This decrement is greater than the increment which can be effected by the operation according to branch 214. Although it the change in the signal just described is a fixed decrement, Embodiments are also possible in which a table, a formula or the Value of the measured input signals at the inputs IN1 to IN5 can be used can to the change of the control signal during the occurrence of a back corona discharge effect to determine.

In the above solution, the voltages on the electropen 22 and 24 increased periodically until the back corona discharge occurs. At the When the back corona discharge occurs, the current conduction angle of the controller 10 is reduced. In this way the electrode voltage is kept at about a peak value, which corresponds to a relatively high degree of efficiency. If no reverse corona discharge occurred and the voltage-current ke-m lines the gas cleaner 26 and 28 were monotonous, then the gas cleaner voltage would increase until a Sparking would be imminent.

Fig. 2 shows a schematic circuit diagram of a typical embodiment the absolute value formation separation stages ABS1, ABS2 and ABS3 according to FIG. 1. It contains two parallel-connected operational amplifiers 48 and 50 (also called arithmetic amplifiers).

Between the output and the inverting input of the amplifier 48 are a diode CR5 and the series connection of an ohmic resistor R20 and a diode CR6 in parallel. The cathode of the diode CR5 and the anode of the diode CR6 are connected to the output of amplifier 48 while its non-inverting- ' the input is grounded. With the input reversing between input P5 and of the amplifier 48 lying ohmic resistor R22, the amplifier provides at the Output junction P6 of the ohmic resistor R20 and the diode CR6 for a limitation (curtailment) of the output signal, which is positive, unipolar and vice versa is.

The amplifier 50 generates a limited (trimmed) and unreversed reproduction of the input signal at terminal P5. Between the inverting input and the output of the amplifier 50 are a diode CR7 and the series connection of a diode CR8 and an ohmic resistor R24 in parallel. The cathode of diode CR7 and the anode of diode CR8 are connected to the output of the amplifier 50 while the non-inverting input is connected to terminal P9 is.

The connection point of resistor R24 and diode CR8 is with the Output terminal P6 connected to ground via an ohmic resistor R26 lies.

The described arrangement transmits positive and negative input signals in each case via the amplifiers 50 and 48, which have a gain factor of one. Since only the amplifier 48 effects an inversion, the output signal at the terminal is set P6 represents the absolute value of the input signal at connection PS. Also other arrangements, such as a conventional full-wave bridge rectifier, can be used can be used for this.

FIG. 3 shows a more detailed circuit diagram of the actuator 10 according to FIG. 1. The main connections of the anti-parallel connected thyristors Q1 and Q2 are respectively connected to the operating AC terminal P2 and the output terminal P4.

Are between the control terminal and the cathode of the thyristor Q1 an ohmic resistor R28 and the secondary winding 52 of a transformer T8 parallel. Between the control terminal and the cathode of the thyristor Q2 are located Ohmic resistor R30 and the secondary winding 54 of a transistor T9 in parallel.

The primary windings 56 and 58 of the transformers T8 and T9 are located between control terminals P10 and P12 in series, their connection point being with is connected to the positive pole of a voltage source. The winding sense of the transformers T8 and T9 are chosen so that when the connection PiO or P12 is briefly earthed or is placed on ground potential, the thyristor Q1 or Q2 in the conductive state is controlled. When the thyristor Q2 is in the conductive state via the terminal P12 is controlled, a positive current flows from terminal P2 to terminal P4 while A negative current from P4 to P2 can be triggered via connection P10. As soon as they are switched to the conductive state or ignited, they remain the thyristors Q1 and Q2 conductive until the voltage drop between their Main connections (between anode and cathode) has dropped to almost zero volts. Actuators according to FIG. 3 are commercially available and somewhat more complicated in practice formed as it is shown here.

4 shows a triggered or triggerable monitoring device in the form of an analog / digital converter AD, which has an output buffer L1 applies (charges), although other arrangements are possible. For example, if an analog device is used instead of the digital device, can the device shown by a known sample and hold circuit be replaced. The converter AD is a commercially available integrated circuit, which converts an analog signal fed to the input INP into parallel 8-bit data. These eight bits are stored in the buffer via the eight lines shown Transfer L1. The operation of the converter AD is triggered by its start input SC a pulse is supplied. The conversion speed or clock frequency is determined by an external clock generator REF, which operates at 1.0 MHz and with the clock input CL of the converter AD is connected. The end of an implementation will signaled by a positive pulse at the terminal EC of the converter AD. The start impulses are generated by a divider 61 (pulse frequency divider) with its input at the connection CL and with its output at the connection SC of the converter AD. at this connection, the divider 61 can carry out the implementation periodically with a repetition frequency trigger that corresponds to the operating speed of the converter AD, e.g. 18 kHz.

The latch L1, which is also called the interlock circuit, consists of two commercially available integrated circuits divided into eight internal Flip-flops store the data generated by the converter AD. The data is saved with the Leading edge or rising edge of each clock pulse at input CL of the buffer L1 is stored if its input blocking terminal DI has an O signal (a low Signal of zero volts) is supplied. The data is from the buffer L1 output via a multiple line DA, provided that the output blocking connection DO an 0 signal is supplied. A 1 signal (+5 volts) at the reset input R of the buffer L1 forces all flip-flops to be reset to the independent state of the signals at their other inputs, so that the buffer is cleared will. The output EC of the converter AD is connected to the reset inputs R of two D flip-flops FF1 and FF2 connected, their data inputs D with a common 1-signal source (+) are connected. The Q outputs of the flip-flops FF1 and FF2 are separate, respectively with the reset input R and the Clock input CL of the buffer L1 connected. The clock inputs C of the flip-flops FF1 and FF2 are each separate connected to terminals SEL1 and FCL. The connection SEL1 is made by the microcomputer COM (Fig. 1) is applied and is also connected to the DO input of the buffer L1 and the input of an inverter 62 (also called NOT element) connected, their Output to the input of an isolation amplifier 64 and the input DI of the buffer L1 is connected. The output terminal 66 of the isolation amplifier 64 is with all Outputs of corresponding isolating amplifiers connected in other converters. In a similar way Way are the outputs of the clock generator REF, the divider 61 and the clock signal connection FCL each connected to the corresponding inputs of other analog / digital converters. These other converters are used to process the signals that are sent to the inputs IN2 to IN7 (Fig. 1) are supplied. The connection FCL receives a synchronization signal, this is done by a microprocessor (described below) in the COM microcomputer (Fig. 1) is used.

A release or trigger signal is sent to the terminal SEL1 by the control device COM fed to the flip-flops of the latch L1 with the multiple line To connect DA for data output. If this trigger signal does not occur, then stands at the connection SEL1 a high signal or a 1 signal, so that the device after 4 converts the signal appearing at the input INP of the converter AD as follows: The delivery of a pulse by the divider 61 triggers the operation of the converter AD which generates an 8-bit parallel data word after about 42 microseconds, the represents the voltage occurring at its input INP. After this implementation a pulse is sent from the output EC of the converter AD to the reset inputs R of the flip-flops FF1 and FF2 are transmitted so that their outputs Q correspond to inputs R and CL of the buffer Apply signals to L1. The next synchronization pulse at the terminal FCL causes a 1-signal occurs at the output Q of the flip-flop FF2 and the Clock input CL of the buffer store L1 is triggered (triggered). Since at connection SEL1 a Signal occurs, so that an inverted, i.e. a 0, signal at the input disable input DI occurs, the 8-bit data word from Converter AD stored. The next start pulse of the divider 61 then causes that the aforementioned sequence of operations is repeated.

It is now assumed that the terminal SEL1 is supplied with a trigger signal so that at the input C of the flip-flop FF1 and at the input DO of the buffer L1 an O signal, on the other hand an inverted signal at the input DI of the buffer L1 1 signal occurs. In this case, the buffer L1 connects its inner ones Flip-flops with the multiple line DA as long as the 0 signal at the connection SEL1 pending. In this way, the data are therefore transmitted on the multiple line DA. It should be noted, however, that the buffer is on because of the 1 signal its input DI does not respond to clock signals at its clock input CL. As soon the output has been triggered, therefore no attempt is made to modify the data. If, on the other hand, a 1 signal occurs at the connection SEL1, the flip-flop FF1 becomes over its clock input C tilted. The reset input is therefore from the Q output of the flip-flop FF1 R of the latch L1 is supplied with a signal which resets its flip-flops (sets to "O"). This condition means that the elapsed time was not enough the converter AD to store a new data word in the buffer To enable L1. When the repeater ÄD has completed another repositioning cycle it sends a pulse to the reset inputs R of the flip-flops via its output EC FF1 and FF2. These flip-flops then lead the inputs R and CL of the buffer L1 signals too.

In this state, the buffer store L1 can store a new data word from converter AD when the next synchronization pulse occurs at connection FCL take up. This new storage is repeated in the manner described as long as how there is a 1-signal at connection SEL1.

The signal fed to the connection INP of the converter AD is supplied by the connection IN1 removed, which corresponds to the input in the same way designated in FIG. The input filter shown is a low-pass filter with an ohmic resistance R31 and a capacitor C1, the connection point of which with the input INP of the converter AD is connected. The other terminal of the capacitor Cl is grounded during the the other terminal of the resistor R31 is connected to the output of the isolation amplifier 68 whose output is at the INI connection. Curves showing the signal at the connector IN1 are shown in timing diagram 8B of FIG. The course of the Voltage at the high-voltage transformer T1 (Fig. 1) and at the gas cleaner 26 (Fig. 1) are shown in timing charts 8A and 8C of FIG. 8, respectively. Like the diagram 8B (Fig. 8) shows, the signal at input IN1 has the form of a ramp or sawtooth signal with occasional high frequency pulses occurring during the oblique signal course appear. These high frequency pulses indicate the impending or occurrence of Spark on.

The circuit between the terminals IN1 and INP is a Input filter that is designed to have the sensitivity for the impending sparking increases. Although this circuit is preferably is a low-pass filter, it can also be designed differently. For example, she can an integrator means or a band pass filter or other processing circuit exhibit. The particular circuit used depends on the sensitivity desired and the expected waveform. The aforementioned integrator device can be one known integrator with an arithmetic amplifier with negative capacitive Have feedback (negative feedback).

FIG. 5 shows the microcomputer COM of FIG. 1 in a more detailed manner Block diagram. Although the microcomputer shown has two microprocessors As has already been mentioned, PRC1 and PRC2 can also be an analog one instead circuit be used. The processors PRC1 and PRC2 are connected with common multiple lines ADR and DA. The lines ADR are multi-bit lines, to which the processors PRC1 and PRC2 supply encrypted address information, These addresses determine a certain storage location in the memory MEN and initiate this, the information stored under this address via the multi-bit data lines Output DA.

The processors PRC1 and PRC2 and the memory MEM are involved are commercially available integrated circuits.

With both processors PRC1 and PRC2 are ports 66, 72 and FCL tied together. Via the connection FCL already mentioned in connection with FIG. 4, from transmit a synchronization clock signal to a clock generator (not shown), which controls the operational sequence of the processors PRC1 and PRC2. The terminal 72 is after 75% of a half-wave of the operating AC voltage has elapsed at input 12 (Fig. i) a measurement signal is supplied. The circuit generating this measurement signal is shown below still described. Via the connection 66, which has already been mentioned in connection with FIG a confirmation signal is supplied which confirms that .an analog / digital converter has been triggered by the processor PRC1 or PRC2.

A timing device is shown as a decoder MX.

The MX decoder solves each individual analog / digital converter normal operating conditions in each half-wave of the input 12 (Fig. 1) AC operating voltage off once.

The decoder MX responds to address words which it receives via the Address lines ADR are supplied. Put the signals on these lines several of the numerous analog-to-digital converters that are installed in the auxiliary equipment 42 (Fig. 1) are included. One of these converters is the converter AD according to Fig. 4. The decoder MX has for each of the analog / digital converters that it triggers or can trigger, a release or. Trigger line. The lines -SELN (Fig. 5) therefore include at least seven lines to trigger the seven with the seven Inputs IN1 to IN7 (Fig. 1) connected converter.

One of these trigger lines is the trigger line SEL1 in FIG. 4. The decoder MX also has the following for each of the input and output devices are described, a line.

The measured values fed to the processors PRC1 and PRC2 are in a Storage device stored, which is shown here as a memory MEM and eight Read-only memory ROM in the form of integrated circuits and twenty random access memories Has RAM in the form of integrated circuits. Other commercially available memories can also be used. These storage devices also store the computer program, which is mainly stored in the integrated read-only memory ROM.

The program controls the COM related to the microprocessor (Fig. 1) and the diagram of Fig. 9 described operations. Essentially the program causes the periodic triggering of the analog / digital converter the auxiliary device 42 (Fig. 1) to measure the condition of the gas purifiers.

As mentioned earlier, the amounts and changes are made to this Compare parameters with specific setpoints stored in memory, to determine whether the actuator 10 (Fig. i) needs to be readjusted. To this Way, the program sets the gas cleaner voltage to the highest value, the does not cause unnecessary sparking or back corona discharge effects. The one to run the special operations described in connection with FIG. 1 are required Program commands are clear to the person skilled in the art. Furthermore, the skilled person is able to to choose a different order of the program commands. So all measurements of the Executed in sequence before any logical program instruction is executed will. Instead, the measurements can also be carried out immediately before the point in time in which they are needed for a special calculation or logical decision will. Furthermore, the above-described response to impending sparking can be used or for back corona effects in two separate subroutines be that in any Sequence can run. aside from that data can be recorded frequently and logical decisions can be made at certain time intervals be taken so immediately that the program as running in real time can be viewed. Such a real-time interval is a time interval in which sparking occurs, as mentioned earlier.

Since changing the program is relatively easy, you can such changes may be made by the operator from time to time. For example, the operator can change certain operating setpoints, if the gas cleaner is to be used for an unusually polluted exhaust gas or when the ambient temperature or humidity is unusual.

It should also be noted that the block diagram of Fig. 5 is simplified, but the structural details not shown in the frame technical ability. Then the capacity of the processors PRC1 and PRC2 chosen so large that it can be used with accessories such as knockers according to US-PS 4 086 647 can work together.

Fig. 6 illustrates peripheral input and output devices associated with the processors PRC1 and PRC2 (Fig. 5) interact in the form of a block diagram In practice, the one shown in Fig.

6 illustrated embodiment is more complicated, but suffices simplified representation to explain the basic mode of operation.

Two seven-segment display devices 76 and 77 are represented by one Interface circuit 78 acted upon. Circuit 78 includes latches (Interlocking or self-holding circuits), which the data lines DA encrypted transmitted information depending on a trigger input pulse save on line SEL3. Decoding driver stages control after storing in circuit 78 the numerical Display devices 76 and 77 so that the operator receives the data from processors PRC1 and PRC2 (Fig. 5) formed information is displayed. The lines SEL3 and SEL4 form a part the lines SELN (Fig. 5), while the lines DA are the aforementioned Multiple lines are involved.

The operator can use switches SW1 and SW2 to be operated manually Enter information. These switches load buffers in circuit 79, their content by a trigger pulse on the line SEL4 via the lines DA can be output. The switches SW1 and SW2 can be larger Part of a keyboard for entering alphanumeric information about the lines Act there. The special design of the integrated circuits in the blocks 78 and 79 is well known, so a further explanation of the device according to Fig. 6 is not required.

Fig. 7 shows some details of the in the secondary device 44 (Fig. 1) included circuit. As you can see, this drawing represents a block diagram with logical components.

In practice, however, this circuit can be additional or different Have logic links and reverse stages (NOT links). The ones already mentioned Data lines DA transmit an 8-bit control signal and are provided with data inputs of a buffer L4, whose data outputs are connected to the data inputs of a Intermediate storage L6 are connected. The data outputs of the buffer memory L6 are with preset inputs of a counter in the form of a preset Down counter 80 connected. The latches L4 and L6 are integrated circuits with eight flip-flops each. The storage of data is effected in that their clock inputs CL are each supplied with a high signal or 1 signal. the Clock inputs CL of the buffers L4 and L6 are each with connections SEL and 120 connected. An input disable input DI of the buffer L6 is through an inverter 82 is controlled, the input of which is connected to the terminal SEL. The application of a signal to the input lock input DI of the buffer L6 causes it to be deleted or reset to 0 in all places. The connection SEL is connected to one of the lines SELN (FIG. 5). The connection SEL is ins Negative controlled when a new control signal is generated.

Terminal 120 is acted upon by a local frequency control loop, the one pulse shaper 84, a phase comparator PC, a voltage controlled The pulse shaper 84 contains an oscillator VCO and a frequency divider DIV a decoupled comparator that generates a square wave with the same frequency as generated by the operating AC voltage at input 12 (see also FIG. 1). Of the voltage-controlled oscillator VCO, the output signal of which has a setpoint frequency of 122.88 kHz is applied to the frequency divider DIV, which generates five output signals, whose frequencies are equal to the frequency of the oscillator VCO divided by 2n. For example, at the input frequency of 122.88 kHz, the frequency of the signals to the Outputs 30720, 480, 240, 120 and 60 respectively 30720, 480, 240, 120 and 60 Hz. The The phase of the 60 Hz signal at connection 60 becomes synchronous with the AC voltage in the comparator PC Output signal of the pulse shaper 84 compared. The output voltage of the comparator PC controls the oscillator VCO so that its phase position corresponds to that of the operating AC voltage is rigidly synchronized at the input 12 in a manner known per se. The components this frequency control loop consist of integrated circuits that are commercially available are available. A NOR gate 92 here forms a logical combination device. The NOR gate 92 has eight inputs that connect to the data lines between the latches L4 and L6 are connected, and generates a 1-signal when on a signal is available on all data lines.

The signal appearing at terminal 120 becomes the. Trigger input of a monostable multivibrator 86 supplied, the one pulse with a duration of about 65 microseconds generated. The output of the monostable multivibrator 86 is fed to the reversing clock input C of a D flip-flop FF4, its connections D, S and Q each with ground and earth, the output of the reversing stage 82 and the one Input of a NOR link 88 are connected. The other entrance of the NOR link 88 is connected to the output of monostable multivibrator 86 and connected to one input of an OR gate 90, the other Input of this OR link element 90 with the output of a NOR link element 92 is connected. The output of the NOR gate 88 has reset inputs R connected to the buffer Lhund L6.

The output of the OR gate 90 is connected to the preset enable input PE of the down counter 80 connected, the clock input CL with the output of a AND gate 94 is connected. The mentioned output 30720 is with a non-inverting input of the AND link 94 connected, its inverting Input is connected to the carry output CO of the counter 80. The carry output CO acts on a triggering device, which is shown here as a flip-flop FF5. A blocking device 96, which is shown as a phase comparator, is connected to this and a first link 100, a second link 102 and has a third link 98 acted upon by these. Although the Members 98, 100, 102 are shown as NAND, OR and NAND gates, respectively those the NAND gate 98 separated by the OR gate 100 and the NAND gate 102 is acted upon, other arrangements of logic elements are also possible. The output of the NAND gate 98 is connected to the input D of the flip-flop FF5.

A polarity display device is shown here as a control device Form of the flip-flop FF6 shown.

In each case one input of the logic elements 100 and 102 is connected to the Terminal 60 is connected, while the other two inputs are connected to output i (line VA) of the D flip-flop FF6 are connected.

As can be seen, circuit 96 produces a 1 signal on the line VC when the signal at terminal 60 is in phase with that at output Q of flip-flop FF6 i.e. both are the same (1 or 0 signals).

The inputs D and C of the flip-flop FF6 are each connected to the terminal 60 and the output Q of the flip-flop FF5. The input C of the flip-flop FF5 is connected to the output of an AND logic element 104, the inputs of which each with the carry output CO of the counter 80 and the output of a limiting device 106 are connected. The device 106 is activated by the signals at the connections 120 and 30720 controlled so that, it generates a positive pulse, its duty cycle can be set manually. The trailing edge of this pulse is caused by the signal on Port 120 synchronized.

The structure of the device 106 is similar to the structure of the device which is connected to the counter 80. The reset input R of the flip-flop FF5 is connected to the output of an OR gate 108, the inputs of each connected to a connection SYSRS and the output of the OR gate 90 are. A manually adjustable override signal is fed to the connection SYSRS. If a 1-signal is fed to the connection SYSRS, the controller 10 (Fig. 1) locked.

Between the base of an NPN transistor Q4 and the output of a AND connection element 110 to 0 is an ohmic resistor R32. Between the Base of a transistor Q6 and the output of a NOR gate 112 is an ohmic resistor R34. The outputs Q and 4 of the flip-flop FF5 are respectively connected to one of the inputs of the logic elements 110 and 112.

The other two inputs of these logic elements are common connected to terminal 60. The connections P10 and P12 (see also Fig. 3) are respectively connected to the collectors of transistors Q6 and Q4, their emitters lie on ground. The output Q of the flip-flop FF5 is via a line VB with the Connected to input C of flip-flop FF6.

The operation of the circuit of FIG. 7 will now be described first under normal conditions and then in the event of spark formation. To facilitate understanding is on the timing diagrams 8D through 8H showing the timing relationships between the signals represent lines 60, 120, VA, VB and VC.

The transmission of a control signal is triggered by a negative pulse at the connection SEL (Fig. 7). Assume that this transmission is short occurs before the end of a half cycle of the AC operating voltage at input 12, namely with anticipation of the regulation desired for a following half-wave. This negative trigger pulse at the connection SEL is reversed by the inverter 82, which controls the set input S of the flip-flop FF4, so that at its output Q a 1 signal occurs. This 1-signal is fed to the NOR gate 88, so that this logic element the reset lines R of the latches L4 and L6 supplies a 0 signal. The trailing edge of the negative pulse at the SEL terminal triggers the clock input CL of the buffer L4, so that this is the Lines DA stores pending data.

The phase-locked with the operating AC voltage present at input 12 synchronized port 120 creates a positive going transition at the end the instantaneous half-wave of the operating AC voltage at input 12. The connection 120 therefore controls the clock input CL of the buffer L6 and causes it to the data from the buffer L4 at the end of this and each subsequent half-wave to take over the operating AC voltage. The signal on terminal 120 also triggers the monostable multivibrator 86, which is connected to the preset enable input PE of the down counter 80 via the OR gate 90 a positive pulse feeds. This causes a presetting of the counter 80. The presetting inputs of counter 80 are shown as inverting or complementing inputs. Accordingly, it becomes the binary complement or 255 minus the numerical output of the intermediate memory L6 is supplied to the counter 80 for presetting.

Provided that the binary number output from the buffer memory L6 was not zero, appears at the transfer output CO of the counter 80 a 0 signal that the AND logic element 94 the transmission of the 30.72 kHz signal from terminal 30720 to clock input CL of counter 80 is permitted. As soon as the output signals of the monostable multivibrator 86 and the OR gate 90 to zero go back, the AND logic element 94 leaves the counter 80 from the preset, complemented input value counting down with a frequency of 30.72 kHz. This should be explained in more detail using a numerical example: If the buffer L6 outputs the number 100, the counter 80 is preset to 155 so that it is approximately counted down to zero in five milliseconds. The one from the cache L6 output number is proportional to the current flow angle of the actuator 10 (Fig. 1 and 2). As soon as the counter 80 has reached the count value zero, it generates at the transmission output CO has a 1-signal that the further supply of clock signals to the counter 80 via the AND logic element 94 blocks.

As you can see, an O signal appears at output CO of counter 80, when the trigger pulse is applied to terminal 120. This transition into the state occurs periodically and in each half-wave of the operating AC voltage applied to input 12 once. The duration of the O signal at the carry output CO is proportional to the binary Complement of the data stored in the buffer 6. Because the signal at the carry output CO is periodic, it can also be viewed as a positive impulse, its Duration corresponds proportionally to the non-complemented data coming from the cache L6 can be read out.

Since normal conditions have been assumed, let us now assume that the signals supplied via the connection SYSRS and the output signal of the device 106 are 1 signals and the output signal of the NOR gate 92 is a signal is, in all relevant time periods. It is also assumed that the flip-flop FF6 is reset.

With this assumption, the next positive transition corresponds of the signal at terminal 60 at the beginning of a positive half-wave of the AC operating voltage at input 12. Simultaneously with this, there is a positive in the signal at connection 120 Transition, while thereupon a negative in the signal at the carry output CO of the counter 80 Transition occurs. Since the signals at the terminal 60 and at the output Q of the flip-flop FF6 are now in phase, circuit 96 introduces the D input of flip-flop FF6 positive signal too. The positive transition of the signal at terminal 120 causes the Transmission of a short pulse via components 86, 90 and 108 to the reset input R of the flip-flop FF5, so that at its outputs Q and Q each have a 0 and a 1 signal occurs. As a result, the gates 110 and 112 lead the bases of the Transistors Q1 and Q2 each apply signals so that they are blocked without any further effect will.

After a time determined by the counter 80, occurs in the counter Transfer output signal has a positive transition in the manner described above. This signal increase is via the AND logic element 104 the clock input C des Flip-flop FF5 supplied. Since there is a 1 signal at input D of flip-flop FF5, how has already been mentioned, the transition at its input C causes it to be its state changes. Because of this change a 1-signal to one input of the AND logic element 110 is supplied and the other input of the AND gate 110 is the 1 signal receives from terminal 60, the AND gate 110 now controls the transistor Q4 through. Turning on transistor Q4 overfires thyristor Q2 (FIG. 3) the pulse transformer T9. In this way flows through the actuator 10 (Fig. 1) a positive current during the remainder of the instantaneous half-wave.

The aforementioned change in the state of the flip-flop FF5 has a positive effect Transition at clock input C of flip-flop FF6. There is still a 1 signal at its input D. pending, the flip-flop FF6 also changes its state so that it is at his exit Q emits an O signal. Because this output signal now is out of phase with the signal at terminal 60, circuit 96 applies the input D of the flip-flop FF5 to an 0 signal without this having any further effect.

At the beginning of the next half-cycle of the operating AC voltage present at input 12 appears in the signals at the terminals 60 and 120 a negative or positive Crossing.

Similar to the previous half-wave, the flip-flop becomes FF5 reset again. After this change, the signal at connection 60 is again with the signal at the output Q of the flip-flop FF6 in phase so that the circuit 96 corresponds to the input D of the flip-flop FF5 supplies a 1 signal. In a similar way as before, the Counter 80 at its carry output CO during a time that is determined by the buffer L6 corresponds to the preset number, an O signal. When this signal at the carry output CO finally executes a positive transition again, this is via the AND logic element 104 is fed to the clock input C of the flip-flop FF5. Since its entrance D now a 1 signal is supplied, the flip-flop FF5 changes its state so that it is the one input of the NOR logic element 112 supplies an 0 signal, with the other Input of this NOR link element 112 also receives an 0 signal from terminal 60 is fed. As a result, gate 112 controls transistor Q6 and this in turn through the thyristor Q1 (Fig. 3). About the controlled thyristor Ql now flows a negative one during the remainder of the current half-wave Current. The just mentioned change of state of the flip-flop FF5 also causes the signal at its output Q triggers the clock input C of the flip-flop FF6, so that the flip-flop FF6 also flips or changes its state. Since the signal is on Output Q of flip-flop FF6 comes out of phase with the signal at connection 60, the circuit 96 supplies an 0 signal to the input D of the flip-flop FF5 without this has an effect. In this state, the device is prepared so that they go through a further cycle in the manner described can. Thus, at the beginning of the next half-wave, the signal at connection 60 comes along again the signal at output Q of flip-flop FF6 in phase.

Assume now that instead of continuing normal operation sparking occurs before and during the following half-wave. This will the transformer T1 (Fig. 1) overloaded and driven into saturation. Thereupon the source 22 (FIG. 1) supplies a binary 0 signal to the lines DA (FIG. 3). Shortly before the start of this next half-wave, this 0 signal is entered in the buffer L4 and L6 transferred. As a result, the input signals of the NOR gate 92 all zero so it produces an 1 signal. Regardless of whether the counter is 80 is just counting, this 1-output signal of the logic element 92 is via the logic element 90 transmitted so that the counter 80 before this next half-wave to its maximum Count value is set. Since it was also assumed that the sparks before and during this next half-wave lasts, the 1 output signal of the NOR logic element remains 92 available. As a result, the output signal also remains at the carry output CO of the counter 80 is zero during this entire half-wave.

Since the flip-flop FF5 is not triggered in this next half-wave, neither this nor the flip-flop FF6 changes its state. After this half-wave has elapsed therefore get the signal at terminal 60 and the signal at output Q of the flip-flop FF6 out of phase. The circuit 96 then leads the input D of the flip-flop FF5 an O signal too. As long as this signal lasts at input D, the flip-flop FF5 does not toggle, so that the transistors Q4 and Q6 remain blocked and the controller 10 (Fig. 1 and 3) keep locked. Therefore, if the logic element 92 (Fig. 7) blocks the actuator 10 (Fig. 1) for a half-wave, the operating power or Power supply not switched on again in the next half-wave. Before therefore not the phase equality between the signals at terminal 60 and output Q des Flip-flop FF6 restored becomes normal operation prevented. In this way, the phase comparison just described makes it easier to that when the power supply is reconnected, this is deliberately not controlled, that the current is switched on after the reconnection different tolerances and ratings to achieve the desired accuracy, performance, speed etc. can be used. The embodiment described can therefore in different Terms may be modified, changed and replaced, and in some cases may some features of the invention are used without the corresponding other features will. Blank page

Claims (6)

Claims 1. Electrostatic gas cleaning device with a voltage regulator that converts an alternating operating voltage into an output voltage generated, which changes depending on a control signal, and with a high-voltage device, characterized by: a high voltage converter device (T1, 18), which by the Voltage regulator (10) is applied and a variable high voltage is generated, and a control device (42 - 44, COM) for generating and changing the control signal, wherein the control device can be operated in such a way that it controls the high-voltage converter device (T1, 18) are suppressed depending on their load being a predetermined one Limit value exceeds during a predetermined limit interval, and after this Limit interval the activation of the high-voltage converter device by the next Half-wave of the operating AC voltage, the polarity of which is opposite to that of the am The beginning of the limit interval is restored, so the device quickly returns is stabilized. 2. Apparatus according to claim 1, characterized in that a conductive Element (16) connected to the high-voltage converter device (TI, 18) and dependent from Changes in the modulation of the high-voltage converter device to generate a high voltage is conductive, the control signal from the voltage is dependent on the conductive element (16). 3. Device n "ch claim 2, characterized in that the control device (42-44, COM) comprises: memory means (L1) for generating a reference signal as a function of at least one previous value of the voltage on the conductive element (16), wherein the control device generates the control signal with a magnitude specified in a predetermined relationship to the reference signal and the instantaneous value of the Voltage is applied to the conductive element (16), so that the gas cleaning device is responsive to parameters indicative of the impending high voltage sparking. 4. Apparatus according to claim 3, characterized in that the conductive Element (16) is predominantly inductive and that the control device (42 - 44, COM) the control signal in the direction of reducing the output current of the actuator (10) as a function of an increase exceeding a predetermined amount the voltage on the conductive element changes. 5. Apparatus according to claim 4, characterized in that the actuator (10) a high voltage transformer (T1) and the conductive element one with the Transformer having linear inductor (16) connected in series 6. Device according to one of claims 1 to 5, characterized in that that the Control device (42-44, COM) has: a triggerable monitoring device (AD) for repeatedly generating a triggered signal depending on the Voltage on the conductive element (16) when the monitoring device (At) is triggered. 7. Apparatus according to claim 6, d a dur c h g e k e n n z e 1 c h n e t that the control device (42-44, COM) reacts to a change between two successive ones triggered signals responds and that the first of the two consecutive Signals is stored in the storage device. 8. Apparatus according to claim 1, characterized in that the control device (42-44, coM) an integrator device connected to the conductive element (16) for generating a representing the time interval of the voltage on the conductive element Has signal. 9. Apparatus according to claim 1, characterized in that the control device an input filter device (43) connected to the conductive element (16) for suppressing frequency components having a predetermined spectrum. 10. Device according to one of claims 1 to 5, characterized by a high voltage measuring device (R8-R14) for transmitting a signal to the Control device that controls the size of the high-voltage converter device (T1, 18) represents the voltage generated, the control device causing the control signal depending on a concurrent increase in that of the high-voltage converter device (T1, 18) generated voltage is advanced step by step. 11. Device according to one of claims 1 to 10, characterized in that that the control device (42-44, COM) the direction of the change of the control signal as a function of a predetermined decrease in that of the high voltage converter device (T1, 18) generated voltage reverses. 12. Device according to one of claims 1 to 11, g e k e n nbz e i c h n e t d u r c h an actuator (10) as a function of a predetermined one Value of the control signal - blocking logic device, the predetermined value as a function of such a decrease in the .Spannungswaldereinrichtung (T1, 18) generated voltage occurs, which corresponds to spark formation. 13. The apparatus of claim 6, d a d u r c h g e k e n n-z e i c h n e t that the control device (42-44, COM) is a timer device (MX) for Triggering of the monitoring device (AD) with a frequency that corresponds to the frequency of the AC operating voltage is proportional, has. 14. The apparatus according to claim 13, characterized in that the Timer device (IYX) the monitoring device (AD) in the last half triggers every half-wave of the AC operating voltage. 15. The device according to claim 1, characterized in that the control device comprises: a polarity display device (FF6) for generating a polarity signal, which indicates the polarity of the current that last flowed through the actuator (10), and a blocking device (-96) which blocks the actuator (10) as long as until the alternating current reverses its polarity with respect to the polarity signal, so that a power supply interruption caused by the control signal, continuation of the power supply with a polarity that follows that opposite that was present before the power supply interruption. 16. The apparatus of claim 15, d ad u r c h g e k e n n z e i c h n e t that the alternating current consists of positive and negative half-waves and the polarity display means (FF6) comprises: a control means having a first and a second state, wherein the control device is operable that during the positive and negative half-waves they are respectively the first and second Assumes state, depending on the current flow through the actuator (10), said locking means (96) comprising: a phase comparator for preventing the triggering of the current flow through the actuator (10) when the first coincidence and second state each with the positive and negative half-waves of the alternating current. 17. The device according to claim 16, characterized in that the Phase comparator (96) has: a first logic element (100) for generating a first signal as a function of the occurrence of the second state during the positive half cycle of the alternating current; a second link (102) for Generating a second signal as a function of the occurrence of the first state during the negative half cycle of the alternating current and a third Linking element (98) for preventing the current flow from being triggered by the controller (10) as a function of the first and second signal. 18. The device according to claim 17, d a d u r c h g e k e n n z e i c h n e t that the control device (42-44, COM) has: a counting device (80) at the beginning of each half cycle of the alternating current with a predetermined clock frequency counts out a number corresponding to the magnitude of the control signal, and a trip device with a trigger and a halt state, which in the absence of the first and second input signal of the third logic element (98) at the end of the count the counter (80) goes into the trigger state and at the end of each half-wave of the alternating current returns to the stopping state. 19. The device according to claim 18, characterized in that the Triggering device depending on a predetermined decrease in the size of the changeable high voltage is reversed into its halted state. 20. The device according to claim 19, characterized in that the Control signal is a digital multi-bit signal and the control device is a logical one Linking device, which the triggering device in its halted state controls when the control signal represents a predetermined digital character that corresponds to sparking in the gas cleaner. 21. A method of changing that of a high voltage converter device an electrostatic gas cleaning device generated high voltage, wherein the Converter device is acted upon by a voltage regulator, the output variable of which changes as a function of a control signal and wherein the converter device is connected to a conductive element which is conductive to an extent that corresponds to the modulation of the converter device for generating the high voltage, characterized in that the voltage across the conductive element is initially measured is that then the control signal is changed in a direction in which the modulation the high-voltage converter device increases, so that the voltage across the conductive Element after a predetermined time interval has elapsed after the initial measurement is measured again and that the control signal is then changed in one direction, in which the output variable of the actuator as a function of a predetermined change the voltage on the conductive element is changed over the predetermined interval. 22. The method according to claim 21, d a d u r c h g e k e n n z e i c That is, the change is a predetermined increment in the magnitude of the voltage across the conductive Element is. 23. The method according to claim 21 or 22, characterized in that the amount of change in the output of the high-voltage converter device over measured the predetermined interval and the control signal in the direction of a decrease the output variable of the actuator as a function of a predetermined Decrease in the output of the high voltage converter device over the predetermined Interval is changed so that back corona discharge effects are reduced. 24. The method according to claim 23, d a d u r c g e k e n n z e i c h n e t that the change in the control signal over the predetermined interval in a predetermined relationship with the decrease in the output of the high voltage converter device stands and that such a decrease in the output of the high-voltage converter device, which exceeds the predetermined decrease and a predetermined limit value, a Reduction of the control signal to a reset value results in which the Sparking in the gas cleaning device stops. 25. The method according to claim 24, d a d u r c h g e k e n n z e i c h n e t that the control signal is held at the reset value at least as long as until the output of the high voltage converter means a predetermined cancellation value falls below. 26. Electrostatic gas cleaning device with a voltage regulator, which generates an output voltage from an operating voltage, which is dependent on changes by a control signal, and marked with a high voltage device by: a high-voltage converter device (T1, 18), which is controlled by the voltage regulator (10) is applied and generates a variable high voltage, a conductive one Element which is connected to the high-voltage converter device (T1, 18) and depending on changes in the modulation of the high-voltage converter device is conductive to generate a high voltage, and a control device (42 - 44, COM), which depends on the voltage on the conductive element (16) generates the control signal, the control device (42-44, COM) - having: a memory device for generating a reference signal as a function of at least an earlier value of the voltage on the conductive element (16), wherein the regulating device the control signal is generated with a magnitude that is in a predetermined relationship to the Reference signal and the instantaneous value of the voltage on the conductive element 16), so that the gas cleaning device responds to parameters that the Indicate impending high voltage spark formation. 27. The device according to claim 26, characterized in that the Control device has: a triggerable monitoring device (AD) for repeated Generate triggered signals that increase the magnitude of the voltage across the conductive element (16) in repeating points in time. 28. The device according to claim 27, characterized in that the control device (42 - 44, COM) for a discrepancy between two consecutive triggered Signals responds and that the earlier of the two successive signals in the storage device (21) is stored. 29. Device according to one of claims 26 to 28, characterized in that that the conductive element (16) is predominantly inductive and that the control device (42 - 44, COM) the control signal in the direction of a reduction in the output variable of Actuator (10) as a function of a predetermined one Amount exceeding the increase in voltage on the conductive element changes. 30. Device according to one of claims 26 to 29, d a d u r c h it is noted that the high-voltage converter device (T1, 18) has a High voltage transformer (T1) and the conductive element one with the transformer has a series-connected linear choke coil (16). 31. Device according to one of claims 26 to 30, d a d u r c h it is noted that the control device (42 - 44, COM) is one with the conductive element (16) connected integrator device for generating a das Having time interval of the voltage on the conductive element representing signal. 32. Device according to one of claims 26 to 31, characterized in that that the control device (42-44, GOM) is connected to the conductive element (16) Input filter means (43) for suppressing frequency components with a having a predetermined spectrum. 35. Device according to one of claims 26 to 32, characterized by a high voltage measuring device (R8 - R14) for the transmission of a signal to the control device, which the size of the high voltage converter device (T1, 18) generated voltage, wherein the control device causes the Control signal as a function of a concurrent increase in the high-voltage converter device (T1, 18) generated voltage is advanced step by step. 34. Device according to one of claims 26 to 33, characterized in that that the control device (42-44, COM) the direction of the change of the control signal as a function of a predetermined decrease in that of the high voltage converter device (T1, 18) generated voltage reverses. 35. Device according to one of claims 26 to 34, characterized by one of the actuator (10) as a function of a predetermined value of the control signal blocking device, the predetermined value depending on such A decrease in the voltage generated by the voltage converter device (T1, 18) occurs, which corresponds to spark formation. 36. Device according to one of claims 26 to 35, characterized in that that the operating voltage is an alternating voltage and the control device (42 - 44, COM) a timer device (MX) for triggering the monitoring device (AD) with a frequency that is proportional to the frequency of the operating voltage, having. 37. Apparatus according to claim 36, characterized in that the Timer device (MX) the Uberwachungseinrich device (AD) in the last half triggers every half-wave of the operating voltage.