Abstract: An electrically variable current limiting reactor which is usable in association with a power supply for an electrostatic precipitator is disclosed herein. The current limiting reactor is capable of having the inductance value thereof varied responsive to system operation conditions. Most particularly the inductance of the current limiting reactor can be modified responsive to the form factor of the sinusoidal AC input current to the power supply transformer. Additionally the inductance of the current limiting reactor can be controlled responsive to the fractional conduction of the full wave rectified current waveform at the output of the full wave rectifier of the power supply. Other conditions can be monitored to control the inductance value of the current limiting reactor such as physical system parameters. An automatic operating control may modify the inductance of the current limiting reactor responsive to the current entering the primary of the transformer of the power supply.

Abstract: A small, battery-powered air purifier can be clipped to a wearer's front shirt pocket or worn suspended from a cord about the wearer's neck. The device includes a housing containing a compact circuit that transforms direct current provided by the battery into a negative high voltage pulsating current which is connected to a sharp metal point contained within a chamber inside the hollow housing. A corona discharge forms on the sharp point, ionizing air molecules and any particulates, and generating ozone. An opening into the chamber is covered by a noncorrosive metal grid connected to the positive terminal of the battery. The negative ions are attracted to this grid, thereby completing an electrical circuit. Movement of the ions to the grid results in mass movement of air which causes a stream of air to emerge through the grid. As the air passes the grid, negatively charged particulates are deposited on the grid.

Abstract: The present invention relates to a method for controlling, in an electrostatic precipitator unit comprising discharge electrodes and collecting electrodes between which a varying high voltage is maintained, a pulsating direct current supplied to these electrodes. In the method according to the invention the frequency, pulse charge and/or pulse duration of the pulsating direct current are caused to vary such that a plurality of combinations of frequency, charge and duration are obtained. For each of these combinations, the voltage U between discharge electrodes and collecting electrodes is measured, and for each of these combinations, a voltage level U.sub.ref is determined, measured or calculated. In a defined time interval, for each of these combinations, either the integral I.sub.k =.intg.U.multidot.(U-U.sub.ref).dt is measured and/or calculated during the time interval, or A.sub.i =U.multidot.(U-U.sub.ref) is measured at a number of points of time, whereupon I.sub.k or linear combinations of A.sub.

Abstract: A filter short circuit is detected when the primary voltage of the high-voltage transformer drops below a specified minimum value and does not rise above the specified minimum value during a specified delay period and a filter current is greater than a specified minimum current. No current is drawn from the external current supply for a variable time delay when a filter short circuit is detected. A filter short circuit count is incremented when a filter short circuit is detected. When the count exceeds a specified, variable limit within a specified, variable time span, the indirect converter is disconnected.

Abstract: An on board electrostatic filter for a vacuum cleaner is disclosed. The filter includes a pair of conductive filaments insulated from one another and disposed close together in a substantially parallel, side-by-side relationship. Circuitry is provided for applying an electrical potential difference between the two conductors. This dual filament conductor is preferably packed into a relatively small volume in a tortuous configuration, to form a random mesh, or can be oriented in a more regular serpentine configuration. Other embodiments describe the mesh electrostatic filter to purify air in an HVAC system.

Abstract: Air purification system where air is subjected to complex electrical field resulting from a DC voltage and AC frequency in kilovolt and kilohertz range respectively, applied to screen assembly in air path. DC amplitude and AC frequency self regulate to selected parameters. Parameters are selectable independently of one another.

Abstract: A system for controlling an electrostatic precipitator adapted to be powered by an alternating power source includes a regulator for regulating at least one precipitator operating parameter in response to at least one control signal, a measurement circuit coupled to the precipitator for providing measurement signals corresponding to at least precipitator secondary voltage and precipitator secondary current. A processor coupled to the measurement circuit and to the regulator generates the control signals.

Abstract: An on board electrostatic filter for a vacuum cleaner is disclosed. The filter includes a pair of conductive filaments insulated from one another and located close together in a substantially parallel, side-by-side relationship. Circuitry is provided for applying an electrical potential difference between the two conductors. This dual filament conductor is preferably packed into a relatively small volume in a tortuous configuration, to form a random mesh, or can be oriented in a more regular serpentine configuration. Other embodiments describe the mesh electrostatic filter to purify air in an HVAC system.

Abstract: An automatic back corona detection and protection system (200) is provided for controlling an electrostatic dust precipitator (80). The system (200) includes a subsystem for monitoring voltage and current parameters of the high voltage transformer/rectifier (70) of the electrostatic dust precipitator system (100). On a periodic basis, automatic back corona detection and protection system (200) tests dust precipitator (80) to determine what operating conditions are conducive to back corona generation, operating parameters being utilized by the energization control (210) during the test, and then operates dust precipitator (80) at voltage and current values below those for which back corona conditions were detected. In detecting back corona, system (200) utilizes two methods of detection (220, 230).

Abstract: An ozonator power supply including a step-up transformer having one end of its primary winding connected to one side of an AC supply, its other end connected to the other side of the AC supply via a pair of switches connected in antiparallel, and a controller for providing switching pulses to said switches for making them conductive during variable portions of alternate half cycles of the AC voltage provided by said supply. An inductor is included in the circuit with the primary or secondary winding of the transformer that resonates with the capacitive impedance of an ozonator, for presenting a substantially non-reactive load to said AC supply.

Abstract: A high-frequency, switching-type protected power supply, in particular for electrostatic precipitators, characterized by the fact of comprising a regulated power supply system for providing direct voltage adjusted at a desired value and at a relatively low voltage; a high efficiency, high-frequency switching system driving a step-up voltage transformer until reaching substantially the desired operating voltage of the precipitator, the secondary circuit of which directly feeds, by means of a rectifier group, the electrostatic precipitator. The high-frequency switching system is controlled in its operation in response to abnormalities indicating an incipient discharge between the electrodes of the electrostatic precipitator to modify the operating conditions in order to avoid the formation of disruptive discharges with consequent possible damage to the entire power supply and/or electrostatic precipitator.

Abstract: In a method for controlling the current pulse supply to the discharge electrodes of an electrostatic precipitator unit in order to achieve maximum separation of dust from gases conducted between the discharge electrodes and the collecting electrodes of the unit at issue, current pulses (I) with a given pulse current are supplied to the discharge electrodes. The pulse frequency is varied, and instantaneous values (U.sub.p, U(I=O), U(I=O+1.6)) corresponding to one another, for the voltage (U) between the discharge electrodes and the collecting electrodes are measured for a number of pulse frequencies. Then, the current pulse supply to the discharge electrodes is set to the pulse frequency at which the highest instantaneous value has been measured.

Abstract: The electrostatic potential supply comprises an operating potential source (+V.sub.cc), a transformer (122) having primary (156) and secondary (172) windings, and a resonant frequency, and a high potential rectifier and multiplier (124). The electrostatic potential supply also includes a phase comparator (110) and a voltage controlled oscillator (114) having a free running frequency of substantially the transformer (122) resonant frequency. The phase comparator (110) generates a control signal related to the frequency difference between the signal from the secondary winding (172) and the signal from the primary circuit (110, 112, 114, 116, 118, 102-1, 2) to synchronize the voltage controlled oscillator (114) output frequency substantially with the frequency of the signal from the secondary winding (172). The voltage controlled oscillator (114) is coupled to the primary winding (156) to maintain the operating frequency of the transformer (122) substantially at its resonant frequency.

Abstract: A self-resonating power supply for controlling operation of an electrostatic air cleaner wherein the ouput voltage to the cell is limited to a desired value by means of a regulated feedback circuit so as to prevent nuisance arcing in the cell and to minimize generation of ozone. The feedback circuit detects changes in the output voltage and responds to such changes by changing the biasing of a switching transistor so as to cause the output voltage to return to the desired value.

Abstract: An improved rapper control system for an electrostatic precipitator for adjusting the power supplied to electromagnetic impact rappers to compensate for known effects of temperature variations on the magnetic coil of the rapper. An ambient temperature sensor is located in the vicinity of the rapper and supplies information to a computational-control unit which regulates the voltage and current supplied to the rapper coil or the duration that the power is supplied to the rapper coil in relationship to temperature changes about the rapper coil, to compensate for such temperature changes. Feedback circuits which measure current in the rapper coil may be coupled with the control unit to maintain a constant current flow through the rapper coil.

Abstract: Form factor measurement and fault detection equipment to determine proper sizing of electrical components and efficiency of an electrostatic precipitator (22) by calculating a system form factor from either primary voltage or current. A power source (10) connects serially to an inverse parallel SCR1 and SCR2, to a current limiting reactor (16), and to a T/R set comprising a transformer (18) and rectifier (20) which supply power to precipitator (22). A current transformer (26) senses input current between the reactor (16) and T/R set (18,20) to signal an input scaling and signal conditioner (28) connected to a current meter (34), a voltage meter (39) and a computer (40) having a display monitor (42). The computer (40) is also connected to an SCR control circuit (24) of SCR1 and SCR2. The appropriate electrical characteristic is converted to both its RMS value and average value and then sent to the computer (40).

Abstract: An improved apparatus for generating a negative charge effect in the environment, in which opposite charged spaced electrically conductive plates are dielectric material. A relatively high alternating voltage is applied between alternate spaced plates with sufficient dielectric strength and dielectric constant to withstand the generation of a cold glow discharge or plasma, and withstand the deposit of dirt on them, and withstand exposure to corrosion, humidity, high temperatures, corrosive gases and fumes. A process is disclosed for the separation of undesirable gases and particulates in polluted areas or airstreams. The present invention relates to the excitation, dissociation, and breakdown of gases and other pollutants.

Abstract: A controller can control controlling a precipitator. The controller has a power modulator. The modulator has a control terminal and is coupled to the precipitator. The power modulator is adapted to be powered by an alternating current. The modulator can operate to regulate the drive to the precipitator in response to a control signal on the control terminal. The controller also has a measurement means coupled to the precipitator for providing a plurality of measurement signals corresponding to a plurality of operating parameters of the precipitator. Also included is a processing means having a program. The processing means is coupled to the measurement means and the power modulator for producing the control signal and for regulating the power modulator in response to the measurement signals.

Abstract: A device for power supply of gas-cleaning electrical precipitators comprises two constant voltage sources (1,2), the unlike poles (5,6) of each of the sources being grounded. Two high-voltage commutators made as triode-type thermionic rectifiers (7,8) with a hollow anode (11) are connected between the other unlike poles of each of the constant voltage sources (1,2) and a corona displaying electrode (16) of an electrical precipitator (17). Connected to a cathode (9) and a control electrode (10) of each of the triode-type thermionic rectifiers (7,8) are modulators (18, 19) of alternating polarity voltage which are connected through isolation transformers (38,39) to a control unit (40), the latter being connected to pickups (49,50,51,52) of electrical and physical parameters.

Abstract: A power source apparatus includes a high-voltage power source for applying a high voltage to a charger in a printer or copying machine, series-connected resistors for detecting a voltage of a grid or shield of the charger, and a transistor, inserted between ground and the grid or shield, for controlling the voltage of the grid or shield in accordance with an output from the series-connected resistors. The transistor may be an npn, pnp, or field effect transistor.

Abstract: A voltage supply for an electric filter is disclosed. The supply comprises a high-voltage rectifier, a pulsed voltage circuit including a resonant circuit and a parallel circuit of a thyristor and a diode which controls resonance in the resonant circuit. The thyristor is fired to trigger the resonant circuit and generate an oscillation which is delivered to the filter as a pulsed voltage. In order to prevent damage to the thyristor, it is fired whenever the duration of the current flowing through the diode is shorter than the thyristor recovery time.

Abstract: A balancing system for electrical A.C. air ionizers having at least one discharge electrode adjacently spaced from a proximity ground and connected to the high side of an A.C. high voltage power source includes (a) a capacitor interposed between each electrode and the high voltage source to maintain a bias on each of the electrodes by blocking the D.C. current component across the circuit capacitance between the discharge electrodes and ground, and (b) a by-pass resistor across the circuit capacitance for providing a path to ground to bleed off excess bias so that equal positive and negative ion densities are generated during corona flow, the by-pass resistor having a resistance value which is determined by the parameters of the system's corona characterisitics (including corona onset voltage and average current flow) that will provide a required equilibrium bias for producing the correct ratios of positive and negative ion currents as will balance the ion densities.

Abstract: A self-discharge type pulse charging electrostatic precipitator includes a high-speed switching element through which the electrical charge stored in a condenser is suddenly supplied to the electrostatic precipitator and the charge is dissipated in an internal resistance in the precipitator. A charging section of the electrostatic precipitator for one power source is divided into a plurality of charging sections which are coupled with each other through inductive elements. The electrostatic precipitator includes a device for supplying the electrical charge to each of the divided charging sections through the high-speed switching element successively in a time sharing manner and a charging capacitor having a capacitance which is substantially equal to a capacitance of the divided charging section. The electrostatic precipitator possesses enhanced precipitation efficiency by suppressing the back ionization and realizes reduction in cost of the power source.

Abstract: A method and apparatus for controlling power to a preciptator 27. After each spark the power to the precipitator is reduced to zero, increased along a fast ramp 15 for a fixed period of time and then increased along a slow ramp 17 until a spark occurs. The fast and slow ramp data is computed and stored (memory 48) and then retrieved after each spark. The data retrieved is the data corresponding to the firing angle at the last spark. Apparatus is provided (selector 51 and memory 52) for dividing (frequency divider 45) the retrieved slow ramp data by a number to select the number of sparks per minute. Also the AC current and the AC voltage in the power to the precipitator are detected and the RMS values are obtained (32 and 34) and compared 35 and if the difference is above a predetermined value the power is disconnected (relay 36 and contacts 23 and 24).

Abstract: The pulse voltage for the electrode (12) of a dust separator (10) is generated by a thyristor circuit (19) to be transferred to a dust separator through a transformer (16). It being possible that voltage arcings take place at the dust separator (10), there is the risk, in case of a blocked thyristor (20) that from the secondary of the transformer (16) a high voltage is produced at thyristor (20) to destroy the thyristor. To avoid such an occurrence, a detector (27) is provided which is only responsive to sudden voltage drops whereupon the thyristor (20) is enabled to become conductive so that the energy of the secondary circuit may be discharged to the storage capacitor (24) in the primary circuit.

Abstract: A circuit arrangement for regulating the high-voltage supply of an electrostatic filter for internal combustion motors whose high-voltage output stage (2) is controlled by a pulse-width modulator (3). The high-voltage output stage (2) contains a diode blocking oscillator which gives off a output voltage (U.sub.A) of several kV on the output side. The pulse-duty factor of the output voltage (U.sub.A) is changed as a function of the output current or the output voltage and while taking into account a maximum allowable power. The soot filter (1) can be constantly operated in an optimum operating range in this manner.

Abstract: An electrostatic precipitator is supplied with a d-c voltage of variable level upon which is superimposed a series of voltage pulses. For each voltage pulse, the difference between a positive current-time area and a negative current-time area beneath a current-voltage curve is determined and maximized by changing the pulse amplitude, pulse width, pulse repetition frequency and/or the rate of pulse rise. In addition, the d-c voltage is controlled to have a value at a point of maximum slope of the function of precipitator current with respect to the magnitude of the d-c voltage.

Abstract: Electrokinetic transducing methods and systems are disclosed in which the two electrode arrays confront each other and each electrode in one array is equidistant from the two nearest electrodes in the other array. The electrode arrays are excited by pulsed exciting voltages, the individual pulses of which are preferably all negative or all positive, have durations equal to or less than the pulse intervals, and have rounded leading knees. Embodiments of the invention are disclosed for applications including electrokinetic loudspeakers, ion generators, fans, and electrostatic precipitators.

Abstract: The invention relates to a method and to an arrangement for controlling the respective conduction times of two directionally opposed electrical devices (9,10) which are mutually connected in parallel and permit current to pass therethrough solely in one direction, and which also permit current (I.sub.2) to pass through the primary winding (2) of a transformer during a respective half-period of an A.C. voltage (U.sub.1) applied to the primary winding, this control being effected so that the magnetizing current through the transformer can be advantageously minimized and/or held beneath a given limit value when an asymmetric load (4,5) is applied to the secondary side (3) of the transformer. A magnetizing current in the primary winding corresponding to the load (5) of the secondary winding (3) is controled through the agency of different conduction times of the two directionally opposed devices (9,10).

Abstract: In order to scrub a waste gas, for example, of foreign matter by means of an electrostatic filter, a power supply is provided which contains a converter whose output feeds the primary winding of a high-voltage transformer. The secondary winding is connected to the electrostatic filter via a high-voltage rectifier. Disposed in the intermediate circuit of the converter is a control element for the intermediate circuit current. This shields the supply network against the effects of the power converter commutations and of short-circuits in the filter to a great extent. A limiter for the filter voltage and a temporary separation of the transformer from the inverter in case of filter short-circuits may be provided to reduce the stress on the components which can be made small if a high-frequency working cycle for the setter and the inverter is used.

Abstract: A control system for controlling high power from an AC source for electrostatic precipitators. The AC power is gated both on and off during the same half-cycle of the AC sources. The gating off of the AC power occurs at a time substantially different from the time of the zero crossings of the AC source. The AC source may be gated on and off respectively before and after each peak to provide high voltage to the precipator electrodes while the period of such pulsing is kept short enough to prevent arcing. Additionally, the source may be gated on after one peak and gated off before the next peak, thereby providing high voltage to the electrodes without applying the peak voltage of the AC. Further in accordance with the invention, such gating may be performed using gate turn-off thyristors. The pulses may be symmetric about the peaks or about the zero-crossings of the source. The source may also be gated on and off a plurality of times during each half cycle.

Abstract: Method and arrangement for varying a d.c. voltage occurring between electrodes of an electrostatic dust separator, said voltage being generated by a number of frequency-related pulses together forming a pulse train. A mains voltage (50 Hz) is fed via valve organs (8, 8a) controlled by a control circuit (7) to a transformer (T), the current pulses of which are full-wave rectified (9) and are connected to electrodes (10) of the dust separator. The control circuit (7) is so arranged as to extinguish an even number, being two, four or more, of pulses from the mains voltage between two consecutive pulses supplied to the electrodes of the dust separator.

Abstract: Circuit for the pulsed operation of one or more high frequency ozonizers, having at least one power supply producing a direct current, having a number of circuits corresponding to the number of ozonizers for the derivation of electrical pulses from the direct current, and having a number of high voltage transformers corresponding to the number of the ozonizers, to whose primary side the pulses produced by each of the circuits are fed and whose secondary side is connected each to an ozonizer. The circuits contain, in accordance with the invention, a pulse width control triggered by an oscillator.

Abstract: A solid state thyristor bridge inverter power supply for an ozonator in which the width and the amplitude of the ozonator current can be controlled and the ozonator voltage can be selectively reset. The power supply circuit includes a diode bridge rectifier for converting a commercial AC power main into a direct current power source which is coupled to a current source DC/AC inverter through a inductor and a current detecting circuit. A current amplitude control circuit controls the output current of the DC power source by comparing the output of the detecting circuit with a reference set point. Logic circuits are provided for controlling the frequency and the width of current pulses applied to the ozonator.

Abstract: A method and apparatus for protecting switching elements, and in particular, thyristor switching elements, which are used to supply pulses to a capacitive load, from damage resulting from false triggering signals, i.e., triggering signals not accompanied by actual sparkover conditions in the load. Since termination of normal pulse cycles in such pulser systems are accomplished by a return to high forward voltage across the switching elements, false triggers generated closely prior to such termination and within the forward recovery time of a thyristor switching element present a danger that the termination of a normal cycle will result in a weak turn-on and consequent damage of the switching element. By insuring that all such potentially false triggers have a duration which extends past termination of the pulse cycle damage to the switching element resulting from such false triggers is inhibited.

Abstract: An electrostatic precipitator is fed high voltage pulses by a pulse generating circuit including a high voltage transformer and a first thyristor switch connected in series with a primary winding of the transformer. Magnetic saturation of the core of the high voltage transformer is prevented by recurrently short circuiting the primary winding of the transformer by means of a second thyristor switch connected in parallel to the primary winding. The second thyristor switch is closed for a period of time extending from a first instant following a high voltage pulse crest to a second instant at or before the start of a pulse generating cycle subsequent to the pulse crest.

Abstract: A novel high-voltage pulse power source comprising an ON-OFF type high-voltage switch element, as high-voltage switch element, which can be reset in OFF state immediately after an ON action, and a current blocking mechanism arranged in the charging power source, whereby an output current from the charging source is inhibited by said current blocking mechanism to stop charging and generating of any dynamic current flow into the load during period of time from an ON action of said ON-OFF type high-voltage switch element till an OFF action of the same, and the flow of said output current is restored during an OFF state of said ON-OFF type high-voltage switch element after an OFF action of the same. In addition, a novel pulse-charging type electric dust collecting apparatus equipped with said novel high-voltage pulse power source.

Abstract: A method is disclosed for controlling the operating parameters of an electrostatic precipitator of the type having electrodes energized by pulses superimposed upon a DC-voltage. According to the method, the pulse height (i.e., amplitude) is continuously increased at a predetermined rate and spark-overs are thereby detected as reductions in the precipitator-voltage below a selectable set value and are sorted in different types according to the time of their occurrence and duration. Thereafter, the operating parameters of the precipitator are altered in dependence upon the characteristics of the actual spark-over.

Abstract: A power module for an electrostatic air cleaner in which an electronic power supply circuit and its components are enclosed within a relatively small modular housing having an AC voltage input in the form of plug-in blades particularly adapted to be inserted within a standard or conventional AC electrical outlet, and a cable for transmitting the high-voltage DC output from the housing to the air cleaner.

Abstract: A power supply with automatic arcing control and overload protection includes an electronic switch in an oscillator circuit with a primary winding of a step-up transformer. A high voltage, secondary winding of the transformer is loosely magnetically coupled to the primary winding. The frequency of oscillation of the oscillator circuit decreases as a load impedance across the secondary winding of the transformer decreases. In the case of arcing or shorting of an output circuit of the power supply the frequency of oscillation decreases below a pass band of the output circuit, thereby reducing the output current of the power supply.

Abstract: A spark-over detector for an electrostatic precipitator has a current sensor (3) which provides a signal (a) which is differentiated twice to produce a signal (c). If the level of the signal (c) is above a predetermined level then a level-detecting circuit (7) passes a signal (d) to an AND-gate (8). A second level detecting circuit (9) receives the signal (a) and if this signal is above a predetermined level passes the signal (e) to a timing circuit (10) which provides a signal (f) from a first preset time after having received the signal (e) until a second preset time after the signal (e) has ceased. Thus, if a spark over starts to occur signals (d) and (f) occur simultaneously and the AND-gate produces an output signal (g) which can be used to trigger the thyristor switch circuit of the pulse generator to conduction to prevent thyristor damage or destruction.

Abstract: A pulse generator operating at a frequency preferably somewhat higher than 100 Hz charges a capacitor through a diode and the trailing edge of the pulse switches-in a discharge circuit to discharge the capacitor through the low-voltage winding of a pulse transformer, the high-voltage winding of which charges, through another diode, the high-voltage insulated conductor of an ionizer that cooperates with a point-bearing electrode that is grounded. The high-voltage electrode discharges through a resistor between pulses and the diode assures that ions of the same polarity will be produced. The ionizer is suited for being located inside a spray gun of an electrostatic coating apparatus for charging the coating material particles with the ions without producing an electric field between the spray gun and the workpiece that would interfere with the coating of hollow places of the workpiece because of the so-called cage effect.

Abstract: A method of controlling the pulse frequency of an electrostatic precipitator energized by a pulse superimposed direct voltage, is disclosed in which, for a given direct and/or pulse voltage, the pulse repetition frequency, at intervals which are preset or determined by one or more precipitator or operational parameters, is lowered and then increased stepwise according to a predetermined scale. At each value of the pulse repetition frequency the average current being measured and the transmitted charge per pulse (defined as the average current divided by the pulse repetition frequency) calculated.

Abstract: In the method of controlling the period length of an intermittent voltage supply to an electrostatic precipitator, a search procedure is carried out at predetermined time intervals or at time intervals determined by one or more continuously monitored/measured precipitator or operational parameters. During the search procedure either the number of system voltage half-periods during which the power supply to the precipitator is cut off (the length of the non-conduction (n.sub.p) period), or the number of system voltage half-periods during which the power supply supplies current to the precipitator (the length of the conduction period), are changed according to a predetermined scale or to a scale determined by one or more precipitator or operational parameters. The charge transmitted per system half-period is current in the precipitator divided by the total number of half-periods of conduction per second.

Abstract: A process for optimizing the power consumption of electrostatic precipitators communicating with a boiler or the like includes a load indexed signal fed forward to a field power controller to approximate the required power levels. An optical transducer is provided in the boiler stack for monitoring the emissions therefrom and feeds back a signal to the controller proportional to the emission from the stack to trim the power level. The controller incrementally adjusts the field power by comparing the opacity generated signal to a continuously optimized limit in order to thereby optimize the power consumption by lowering and raising the field power in response to changes in the opacity. The measurement of power permits the process to be extended to include supervision of electrode cleaning, compensation for fields out of service and flow balancing.

Abstract: In order to mitigate the problem of back-corona discharge in electrostatic precipitators, method and apparatus are provided for energizing the precipitator electrodes with repeated bursts of high voltage electrical pulses, superimposed upon a direct current voltage level. Additionally, the voltage of the pulses in a single burst is increased from each pulse to the next pulse during the time period that the pulse burst is applied. The effect of the ramping of the pulse burst voltage is to increase the average electric field and ion density during the pulse burst. The result is substantially higher particle charging which leads to improved particle charging collection efficiency.

Abstract: In an electrostatic precipitator system powered by a primary power source, the power supply has a converter and a high voltage device. The converter can be coupled to the primary power source for producing a converter voltage with a different frequency content. The high voltage device is driven by the converter, producing from its converted voltage a high voltage. This high voltage is influenced by the different frequency content, having at least one frequency component at a predetermined low frequency which is sized to promote efficient precipitation.

Abstract: An electric power source for use in an electrostatic precipitator includes a first high voltage DC source having an output terminal adapted to be connected to discharge electrodes of the electrostatic precipitator. An inductor is connected at its one end through a coupling capacitor to the output terminal. A controlled rectifier is connected at its an anode to the other end of the inductor and has a grounded cathode. A diode is connected in a reversed parallel to the controlled rectifier. There is also provided a second high voltage DC source having a high output impedance and connected to the inductor, and the controlled rectifier is turned on and off by a controller.

Abstract: A circuit for applying unidirectional pulses to a precipitator, in addition to a base d.c. level supplied by a transformer/rectifier set, includes a rectifier, an inverter and a transformer/rectifier set connected to charge a storage capacitor. Discharge of the capacitor into the precipitator is controlled by a chain of unidirectionally conducting devices (thyristors as shown) which are simultaneously triggered at the desired voltage at the capacitor. In other embodiments breakover diodes are used instead of the thyristors.

Abstract: The method of supplying voltage to an electrostatic precipitator, includes periodically reversing the polarity of a supply voltage; intermittently supplying voltage to the precipitator; and the supply voltage polarity being reversed during no-voltage intervals, with the reversing of polarity being delayed with respect to the beginning of the no-voltage interval.