ELECTRONIC DEVICE WITH ADVANCED CONTROL FEATURES

Abstract

An electrostatic device, for example, an electrostatic air cleaner, may be provided with a corona discharge electrode; a collecting electrode; a power source connected to the corona discharge electrode and to the collecting electrode; an electrical parameter sensor; and a power supply system. The control system may receive a signal from the electrical sensor. The control system evaluates the electrical performance of the system and initiates appropriate or corrective action.

Claims

1. An electrostatic device comprising: a corona electrode array; a second electrode array associated with said corona electrode array; a power source connected to said corona electrode array and to said second electrode array; an electrical sensor connected to one of said corona electrode array and said second electrode array; a power source controller connected to said power source and to said electrical sensor; and wherein said power source controller is configured to: (a) make a plurality of readings over a long time from said electrical sensor, store said readings, make a first evaluation of a plurality of said readings stored over a long time, and signal results of said first evaluation; (b) make a plurality of readings over a medium time from said electrical sensor, store said readings over a medium time from said sensor, make a second evaluation of said readings over a medium time and adjust operation of said power source based on said second evaluation of said readings over said medium time, and (c) make a plurality of readings of said electrical sensor and, in response to detection of a substantial change in said readings, substantially reduce an output of said power source and after a delay, restore said output of said power source.

2. (canceled)

3. (canceled)

4. The electrostatic device according to claim 1 wherein said substantial change in said readings represents a spark or pre-spark condition.

5. (canceled)

6. The electrostatic device according to claim 4 wherein said second evaluation of said readings over a medium time frame is responsive to a change in environmental or operational conditions.

7. (canceled)

8. The electrostatic device according to claim 6 wherein said first evaluation of said plurality of said readings stored over a long time is responsive to a change in said readings indicative of a maintenance condition of said electrostatic device.

9. The electrostatic device according to claim 8 wherein said power source controller is further configured to issue a maintenance signal.

10. The electrostatic device according to claim 1 wherein said electrostatic device is an electrostatic air cleaner and wherein said second electrode array is a collecting electrode array.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 shows a block diagram of the proposed invention.

[0033] FIG. 2 shows a time diagram of the corona discharge current and voltage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034] Before the present invention is described in further detail, it is to be understood that the invention is not limited to the particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0035] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0036] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein.

[0037] It must be noted that as used herein and in the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise.

[0038] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

[0039] FIG. 1 schematically shows an electrostatic air filter 101. The electrostatic air filter may have a corona electrode 102 and a collecting electrode 103. The corona electrode 102 may be connected to the high voltage terminal 107 of a power source 105. The low voltage (ground) terminal 108 of the power source 105 may be connected to the collecting electrode 103 through a current sensor 106. The current sensor 106 may be a shunt, a current transformer, a Hall Effect sensor, or any other current sensing device. The current sensing unit 106 may be connected to a control system 104 that controls the power source 105 voltage output magnitude across terminals 107 and 108.

[0040] The control system may include a microprocessor that performs the following actions: [0041] Measures the corona current value from the corona current sensor 106; [0042] Measures the output voltage of the power source 105. This may be a direct measurement or a measurement across a voltage divider (not shown), or any other method for voltage measurement known in the art; [0043] Stores the results of both measurements in a memory; [0044] Changes the voltage generated by the power source 105 in accordance with a built-in algorithm.

[0045] The algorithm itself may be based on the above-mentioned reasoning and may be a built-in microprocessor adjusted for the course of the electrostatic filter performance or adjusted to the specific use. For instance, the electrostatic filter may be used in rather clean air and use one kind of appropriate algorithm, or the electrostatic filter may be used in industrial area with heavy smog and use a different algorithm.

[0046] FIG. 2 schematically shows electrical parameters of a corona discharge device. R is the corona discharge resistance, Ic represents the corona current and VC represents the corona voltage. Initially, nominal voltage is applied to the corona electrodes and the corona current starts to flow. The corona current magnitude (value) is depicted by the curve 205, the corona electrode voltage is depicted by the curve 206. The ratio of Vc to Ic is equal to the corona discharge resistance R (204). As can be seen from these curves, the corona current changes its value depending on the air conditions such as temperature, humidity, density and so forth. These changes refer to the medium processes category. In order to maintain proper (desirable) electrostatic air filter performance (like filtration efficiency or filtered air cleanness) the control system changes the power source voltage Vc (206) in response to the corona current Ic (205) changes.

[0047] The moment spark discharge happens is shown as 207. Current Ic abruptly increases while the resistance R drops almost to zero. This is a fast process. In response to the fast current change, the control system sharply decreases the voltage Vc value. This voltage is kept at low level for several seconds until the air near the corona electrode deionizes. Then, the control system restores the power source operation back to pre-spark level. In the course of further operations, the corona current Ic changes its value at a medium processes speed and the control system adjusts the power source voltage correspondingly. As may be noticed, the resistance R steadily increases its value over the course of time. The corona current steadily drops in value and the control system steadily increases the power source voltage. These steady (average) changes belong to the slow processes category. The control system stores the collected data and sets medium (up and down) process changes apart from slow processes. Slow process usually goes in one direction (increase or decrease the value over the time).

[0048] Over time, the corona current will decrease to the point where the corona voltage increases to its maximum or a threshold level as shown in FIG. 2 at the far right of the graph. The control system may generate a warning signal which may be used to alert a user to take appropriate actions, like replacing or cleaning the corona wire.

[0049] According to another feature, when the control system detects operational parameters exceeding a threshold, the control system may signal a user and/or switch the power source off. The operational parameters may include the potential of the corona electrode, or excessive spark conditions.

[0050] The techniques, processes and apparatus described may be utilized to control operation of any device and conserve use of resources based on conditions detected or applicable to the device.

[0051] The invention is described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.

[0052] Thus, specific apparatus for and methods of the current invention have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the disclosure. Moreover, in interpreting the disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms comprises and comprising should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.