JPS5990648A - Electrical dust precipitator - Google Patents

Abstract

PURPOSE:To enable economization of electric power consumption and to improve dust precipitation performance by providing a switching circuit which conducts intermittently electricity to a control winding of a saturable reactor and a resistor interposed in the electricity conduction circuit thereof. CONSTITUTION:A switching circuit 3 which conducts intermittently electricity to a control winding 6a of a saturable reactor 6 is provided and a resistor 5 is interposed in the electricity conduction circuit thereof in an electrical dust precipitator having a saturable reactor 6 in a power source circuit. The responsiveness of the reactor 6 is improved by the resistor 5, and the electrical dust precipitator which is effective for economization of electric power and has excellent dust precipitation performance is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic precipitator that makes it possible to reduce power consumption and contributes to improving dust collection performance.

As a device for collecting fine particles floating in a gas, an electrostatic precipitator is widely used, which has a discharge electrode that causes corona discharge to charge the fine particles, and a dust collection electrode that collects the fine particles. ing. Regarding voltage application to the discharge electrode, in addition to (a) a device that controls the voltage so that the discharge energy remains at a constant value, and (b) a device that continuously charges a low voltage and superimposes it on top of it. , a device that intermittently applies short-term high-voltage pulses within a range that does not generate sparks, or (c) a device that intermittently applies high-voltage pulses within a range that does not cause reverse ionization of the particles to be collected. It is.

In the case of (a) of these devices, when attempting to suppress the voltage or current for the purpose of saving power or improving efficiency, it is difficult to set the voltage or current, and the applied voltage may be set low. The disadvantage is that the dust collection efficiency is poor. On the other hand, in cases (b) and (c), effective power saving can be achieved, but since the charging time must be shortened, a saturable reactor with a slow response is installed in the charging control circuit of the electrostatic precipitator. However, the application was limited to those equipped with a thyristor control circuit.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power-saving electrostatic precipitator using a supersaturated reactor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrostatic precipitator according to the present invention will be specifically described below based on drawings showing embodiments thereof.

FIG. 1 is a schematic circuit diagram showing an embodiment of an electrostatic precipitator according to the present invention. The AC power supply 11 is connected to the primary winding 7a of the step-up transformer 7 via the load winding 6b of the saturable reactor 6, and the high voltage boosted here is applied to the high-voltage rectifier 8 and rectified.

The positive output of the rectifier 8 is grounded, and the negative output is connected to the discharge electrode 10a via the current limiting reactor 9. discharge 4
The dust collecting electrode 10b facing i10a is grounded. Although the configuration of the main circuit, such as the one shown above, is similar to that of the conventional device, the device of the present invention is characterized by the control circuit connected to the control winding 6a of the saturable reactor 6.

A control AC power supply 1 is boosted to a required voltage by a step-up transformer 2 and is applied to a switching circuit 3. The switching circuit 3 is a semiconductor circuit that repeats opening and closing at a predetermined period, and the voltage interrupted here is collected to the saturable reactor control circuit 4.

The saturable reactor control circuit 4 consists of a rectifier circuit, a short circuit detection circuit, a spark detection circuit, a maximum current setting circuit, etc., and is of a known type per se, and one of its output terminals is connected to the control winding 6a of the saturable reactor 60. The other end of the output terminal is connected to the other end of the control winding 6a via the resistor 5.

Important points regarding the device of the present invention; 1. The resistor 5 is inserted into the control winding 5a (111 circuit) of the saturable reactor 6. The time constant Tc of the supersaturable reactor is Tc =
It is expressed as K-1eC. Here, Rc is the resistance value of the circuit on the control winding 6a side. In the device of the present invention, the time constant Tc becomes small and the responsiveness is improved because Rc and Rc become equal to each other by the interposition of the resistor 5. In addition, step-up transformer 2il
-i This is to compensate for the voltage drop across the control winding 6a due to the interposition of the resistor 5, and is not necessary depending on the voltage of the AC power supply 1.

The apparatus of the present invention constructed as described above operates as follows. That is, the alternating current voltage output from the step-up transformer 2 is turned on and off at a predetermined period by the switching circuit 3. This intermittent alternating current is rectified into direct current by the control circuit 4, and the control winding 6
When the current is applied, an alternating current corresponding to the current value flows through the load winding 6b, and when the current is stopped, the current on the load winding 6b side is also stopped. Therefore, the output of the step-up transformer 7 and the output of the high voltage rectifier 8 are also intermittent, and a high voltage is intermittently applied between the discharge electrode 10a and the dust collection electrode 10b.

Therefore, it goes without saying that it is possible to save power, but if the intermittent period is appropriately selected, the same dust collection effect as in the case of continuous energization can be achieved as in the case of a device equipped with a Zyristor control circuit. In the device of the present invention, the voltage changes at the time of discharging and intermittent voltage of the dust collecting reservoir are performed at a sufficiently high speed, so that the dust collecting effect 5 and the power saving effect are not impaired.

FIG. 2 is a drawing showing the waveform of the high-voltage rectifier 8 output in the device of the present invention taken with an oscilloscope. The upper side shows the current, the lower part shows the voltage. (timing when changes from open to closed),
(b) shows the time when the voltage falls (timing when the switching circuit 3 changes from closed to open). The comb in the photo indicates one cycle of 50 Hz power supply, and the response time is N! It takes about 10 cycles at the time of rising, and about 8 cycles at the time of falling.

Figure 1 shows the second circuit in the case where the control circuit 4 and the control i'+jl1 winding 6a of the device of the present invention are directly connected, excluding the resistor 5.
It is a drawing similar to the one shown in the figure, and (a) shows the rising time, and (b) shows the rising time.
indicates the falling time.

According to this, the response time is a little less than 1 second at the time of rise and about 15 cycles at the time of fall, and it is clear that the response speed of the device A of the present invention is high. Furthermore, it is found that the energization time width in the energization/intermittent cycle can be made as short as about 0.5 seconds to 0.6 seconds. In other words, even if the device is equipped with a saturable reactor, it is possible to control a collector TTG device that can save power without impairing the dust collection effect in the same way as a device equipped with a thyristor control device.

As described above, the electrostatic precipitator according to the present invention has a saturable lea r
The reactor is equipped with a switching circuit that intermittently energizes the control winding of the reactor, and a resistor interposed in the energizing circuit, so the resistor increases the responsiveness of the saturable reactor and saves power. It is possible to realize an electrostatic precipitator with excellent dust collection performance that is effective for Further, the present invention can be implemented by modifying an existing electrostatic precipitator equipped with a saturable reactor, and the present invention is extremely useful because the modification can be easily and inexpensively performed.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram showing one example of the device of the present invention, and FIG. 2 (
A) and (B) are waveform diagrams showing the responsiveness of the device of the present invention;
Figures (a) and (b) are waveform diagrams showing the responsiveness of the device without the resistor 5. 3...Switching circuit 4...Saturable reactor control circuit 5...Resistor 6...Saturable reactor 7...Step-up transformer 8...High voltage rectifier 1. Oa
...Discharge electrode 10b...Collecting electrode Patent applicant Noboru Kono, Patent attorney representing Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1. An electrostatic precipitator having a saturable reactor in the power supply path (1), comprising a switching circuit that intermittently energizes a control winding of the saturable reactor, and a resistor interposed in the energizing circuit. An electrostatic precipitator characterized by: