Patent Application
20080011162
The same reference number represents the same element on all drawings. It should be noted that the drawings are not necessarily to scale.
The collector cell 110 can comprise a combined ionizer and electrostatic precipitator, for example. The electrostatic precipitator and the ionizer operate by creating high-voltage electrical fields, typically in excess of 5,000 volts. Dirt and debris in the air becomes ionized when it is brought into this high voltage electrical field by an airflow. Charge plates or electrodes in the electrostatic precipitator air cleaner, such as positive and negative plates or positive and ground plates, create the electrical field and one of the electrode polarities attracts the ionized dirt and debris. Because the electrostatic precipitator comprises electrodes or plates through which airflow can easily and quickly pass, only a small amount of energy is required to provide airflow through the electrostatic precipitator. As a result, foreign objects in the air can be removed efficiently and effectively.
The ionizer can comprise charge wires and ground plates, wherein the ionizer charges particles in the airflow before the airflow enters the electrostatic precipitator. The charging of the particles can neutralize or kill living organisms. The ionized particles of the airflow are subsequently attracted to ground potential surfaces. As a result, the electrically charged dirt and debris is more likely to be pulled out of the airflow when the airflow passes through the electrostatic precipitator.
The constant current power supply 102 supplies a substantially constant electrical current to the collector cell 110. The constant current power supply 102 is designed to provide the substantially constant current to the collector cell 110 within a predetermined range of voltages.
In some embodiments, the electrical current supplied to the collector cell 110 is about 150 micro amperes (μA), within a predetermined tolerance range.
The constant current power supply 102 provides an output voltage that can vary. The output voltage can fall between an upper voltage threshold VU and a lower voltage threshold VL during normal operation. In some embodiments, the upper and lower voltage thresholds VU and VL can be substantially centered around a desired operating voltage, such as centered around about 5.5 kilovolts (kV), for example. However, other voltage thresholds are contemplated and are within the scope of the description and claims.
At time B, the output voltage exceeds the upper voltage threshold VU. In some embodiments, the upper voltage threshold VU is substantially equal to an open load voltage of the constant current power supply 102. This can be due to a loss of connection in the collector cell 110, poor ionization conditions, etc. The collector cell 110 is therefore performing minimal ionization of the airflow, and as a result the electrical power to the collector cell 110 can be shut down and a failure indication can be generated.
At time C, the output voltage VO drops to zero as the electrical-power is shut down.
At time D, the output voltage is restored and returns to normal. The collector cell 110 resumes operating with the output voltage VO being between the upper and lower voltage thresholds VU and VL. Ionization is again being performed satisfactorily.
At time E, the output voltage drops below the lower voltage threshold VL. As a result, the electrical power is shut down, as the constant current power supply may not be able to maintain a constant current below the lower voltage threshold VL. The drop in output voltage can be due to problems such as arcing and shorting in the collector cell 110, for example. Arcing or shorting can be due to various causes, such as excessive humidity, presence of water or other liquids in the collector cell 110 (such as residual liquids from a washing operation), the presence of excessive (or excessively large) dirt and debris in the collector cell 110, etc. Because arcing or shorting can consume excessive electrical current and because the excessive electrical current can damage the collector cell 110, the electrical power is shut down.
Referring again to
In step 302, the output voltage VO is compared to an upper voltage threshold VU and to a lower voltage threshold VL. The upper and lower voltage thresholds VU and VL can comprise predetermined voltage thresholds. The upper and lower voltage thresholds VU and VL can depend on the parameters of the collector cell 110, including parameters such as physical size, materials used in construction, spacing between plates, etc. In addition, the upper and lower voltage thresholds VU and VL can be chosen for specific operating conditions, including high and low humidity environments and/or high and low temperature environments, for example.
In step 303, if the output voltage VO is between the two thresholds, then the method loops back to step 301 and continues to monitor the output voltage VO. Otherwise, if the output voltage VO is not between the two thresholds, then the method proceeds to step 304.
In step 304, the constant current power supply 102 shuts down electrical power to the collector cell 110. The electrical power can be removed until a person manually re-starts the air cleaner 100, such as by cycling power to the air cleaner 100 or removing the collector cell 110, for example. Alternatively, the constant current power supply 102 can shut down for a predetermined time period and can perform an automatic re-start.
The method can continuously loop in normal operation in order to substantially continuously monitor the output voltage VO. Consequently, any unacceptable output voltage level will be quickly detected and disabled.
