Patent Publication Number: US-2006017808-A1

Title: Flame quality sensor

Description:
BACKGROUND  
      In many applications, natural gas is used to supply fuel for flame in appliances such as water heaters, dryers, broilers, ovens and other appliances. For example, in applications such as recreational vehicles, flame from natural gas is used to produce power for refrigerators and air conditioners.  
      If the flame used for heat does not get proper oxygen, the flame turns from blue to yellow and a sooty deposit is created that lowers heating efficiency and can increase the amount of generated pollution.  
      Regular maintenance can detect the existence of an improperly burning flame. However, in many households, an interval of a year or more can occur between the performance of maintenance. Thus, a deficiency in operation resulting in a sub-optimal flame can be undetected for a long period of time. This can increase the cost of operating the appliance as well as result in the production of unnecessary pollution.  
     SUMMARY OF THE INVENTION  
      In accordance with embodiments of the present invention, a monitoring device includes an imager, a processor and transmission media. The imager is used to capture visual information pertaining to a flame produced by an appliance. The processor processes the visual information to produce processed information. The transmission media is used by the processor to forward the processed information to a monitoring system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a simplified block diagram showing operation of a flame quality sensor in accordance with an embodiment of the present invention.  
       FIG. 2  is a simplified block diagram of an image sensor in accordance with an embodiment of the present invention. 
    
    
     DESCRIPTION OF THE EMBODIMENT  
       FIG. 1  is a simplified block diagram showing operation of a flame quality sensor in accordance with an embodiment of the present invention. A flame  13 , within an appliance  11 , is optically detected by an imager  14 . A pipe  12  delivers gas that is fuel for flame  13 . For example, appliance  11  is a water heater. Alternatively, appliance  11  is a dryer, a furnace, a broiler, an oven, a refrigerator, an air conditioner or another appliance that uses a flame.  
      A microprocessor (μP)  15  is used to process the image received from imager  14 . The image produced by imager  14  can include, for example, information about color, brightness, and/or size of flame  13 . Microprocessor  15  forwards the image information to a monitoring system  19 , for example via a radio  16 . For example, radio  16  uses an antenna  17  to transmit information to an antenna  18  of monitoring system  19 . Alternatively, microprocessor  15  forwards the image information to a monitoring system  19  via other wireless, electrical or optical transmission media. For example, the electrical transmission media is wire. For example, the optical transmission media is fiber optic cable.  
      For example, microprocessor  15  passes a sufficient amount of the imaging information received from imager  14  to allow monitoring system  19  to reconstruct the entire image received by microprocessor  15  from imager  14 . Alternatively, microprocessor  14  forwards to monitoring system  19  only a few bytes of information indicating, for example, color, brightness, and/or size of flame  13 .  
      For example, monitoring system  19  uses a valve  20  to shut down the gas flow in pipe  12 , extinguishing flame  13 , when the quality of flame  13  degrades below a predetermined level. Alternatively, or in addition, monitoring system  19  sets off an alarm when the quality of flame  13  degrades below a predetermined level.  
       FIG. 2  is simplified block diagram of an embodiment of imager  14  implemented as a single color sensor that, for example, has a spectral measurement of wavelength from 400 nanometers (nm) to 700 nm. For example, the color sensor can be implemented as a complementary metal-oxide semiconductor (CMOS) image sensor.  
      In response to incident light  23 , imager  14  generates three separate output voltages (V): a V(R) signal  24 , a V(G) signal  25  and a V(B) signal  26 . V(R) signal  24  is an analog signal that indicates the proportional red component of incident light  23  upon imager  14 . For example, V(R) signal  24  is a DC voltage between 0 and 3 volts. V(G) signal  25  is an analog signal that indicates the proportional green component of incident light  23  upon imager  14 . For example, V(G) signal  25  is a DC voltage between 0 and 3 volts. V(B) signal  26  is an analog signal that indicates the proportional blue component of incident light  23  upon imager  14 . For example, V(B) signal  26  is a DC voltage between 0 and 3 volts.  
      V(R) signal  24  is generated by a photo sensor  27 , an amplifier  29  and a feedback resistor  28 , which are all located within imager  14 . Photo sensor  27  includes an integrated color filter in red. Photo sensor  27  is connected to a power input signal  21 .  
      V(G) signal  25  is generated by a photo sensor  30 , an amplifier  32  and a feedback resistor  31 , which are all located within imager  14 . Photo sensor  30  includes an integrated color filter in green. Photo sensor  30  is connected to power input signal  21 .  
      V(B) signal  26  is generated by a photo sensor  33 , an amplifier  35  and a feedback resistor  34 , which are all located within imager  14 . Photo sensor  33  includes an integrated color filter in blue. Photo sensor  33  is connected to power input signal  21 .  
      An analog-to-digital converter (ADC)  36  converts V(R) signal  24 , V(G) signal  25  and V(B) signal  26  to a digital signal sent to microprocessor  15 . The digital signal, for example, includes separate red, green and blue values.  
      Depending upon the imaging requirements, more sophisticated embodiments for imager  14  can be used. For example, if very accurate images are required, a charged coupled device (CCD) can be used for light-sensing. A CCD contains an array of photosensitive cells that react to incoming light based on the properties or the incoming light. The properties include, for example, intensity and color. The CCD captures incoming light via an optical lens and generates various analog signals that are converted to a DC signal utilized by microprocessor  15 .  
      The foregoing discussion discloses and describes merely exemplary methods and embodiments of the present invention. As will be understood by those familiar with the art, the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.