Patent Publication Number: US-9846148-B2

Title: Method and device for dissolved gas analysis

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 14/134,525, filed Dec. 19, 2013, which claims priority to IN Application No. 5318/CHE/2012, filed Dec. 19, 2012. The disclosures of the above-identified co-pending applications are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The subject matter disclosed generally relates to measuring and testing of dissolved gases, and more specifically to a method and apparatus for selectively detecting and monitoring dissolved gases in a fluid, such as transformer oil. 
     BACKGROUND 
     Electrical equipment, particularly medium-voltage or high-voltage electrical distribution equipment, typically requires a high degree of electrical and thermal insulation between components. Accordingly, it is well known to encapsulate components of electrical equipment, such as coils of a transformer, in a containment vessel and to fill the containment vessel with a fluid. The fluid facilitates dissipation of heat generated by the components and can be circulated through a heat exchanger to efficiently lower the operating temperature of the components. The fluid may also serves as electrical insulation between components or to supplement other forms of insulation disposed around the components, such as cellulose paper or other insulating materials. Various fluids having the desired electrical and thermal properties can be used. However, electrical equipment is typically filled with various oils, such as castor oil, mineral oil, and/or a synthetic “oil” such as chlorinated diphenyl or silicone oil. 
     Often electrical distribution equipment is used in an environment where failure can be very expensive or even catastrophic because of a loss of electric power to critical systems. Also, failure of electrical distribution equipment ordinarily results in a damage to the equipment itself and surrounding equipment, thus requiring replacement. Further, such failure of electrical distribution equipment can cause injury to personnel or other property. Therefore, it is desirable to monitor the status of electrical equipment to predict potential failure of the equipment through detection of incipient faults and to take remedial action through repair, replacement, or adjustment of operating conditions of the equipment. 
     A known method of monitoring the status of fluid-filled electrical equipment is to monitor various parameters of the fluid. For example, the temperature of the fluid and the total combustible gas (TCG) in the fluid is known to be indicative of the operating state of fluid-filled electrical equipment. Therefore, monitoring these parameters of the fluid can provide an indication of any incipient faults in the equipment. For example, it has been found that carbon monoxide and carbon dioxide increase in concentration with thermal aging and degradation of cellulosic insulation in electrical equipment. Hydrogen and various hydrocarbons (such as acetylene and ethylene, and their derivatives) increase in concentration due to hot spots caused by circulating currents and dielectric breakdown such as corona or arcing. Concentrations of oxygen and nitrogen tend to indicate the quality of the gas pressurizing system employed in large equipment, such as transformers. Accordingly “dissolved gas analysis” (DGA) has become a well-accepted method of discerning incipient faults in fluid-filled electric equipment. 
     Generally, an amount of fluid is removed from the containment vessel of the equipment through a valve. The removed fluid is then subjected to testing for dissolved gas in a lab or by equipment in the field. This method of testing is referred to herein as “off-line” DGA. Since the gases are generated by various known faults, such as degradation of insulation material or other portions of electric components in the equipment, turn-to-turn discharges in coils, overloading, loose connections, or the like, various diagnostic theories have been developed for correlating the quantities of various gases in fluid with particular faults in electrical equipment in which the fluid is contained. 
     Known methods of off-line DGA typically require extraction of gases from the fluid for several quantitative analyses. These extracted gases are often analyzed by using photo-acoustic spectroscopy or gas chromatography. The gas concentration in the fluid is generally calculated from the measured concentrations of the extracted gases. However, these methods suffer from inaccuracy, uncertainties and repeatability issues generally involved with the complicated extraction process. In addition to this, the gas concentration in liquid is calculated from the measured concentrations of the extracted gases. The calculations have several assumptions involved, leading to errors and uncertainties. 
     BRIEF DESCRIPTION 
     These and other drawbacks associated with such conventional approaches are addressed here by providing a system in accordance with various embodiments. The system includes at least one source for irradiating electromagnetic radiation into a sample fluid and a reference fluid resulting in a change in a temperature of the sample fluid and a change in a temperature of the reference fluid, and a processing subsystem that monitors and determines a concentration of a gas of interest dissolved in the sample fluid based upon a difference between the change in the temperature of the sample fluid and the change in the temperature of the reference fluid, wherein the reference fluid does not contain the gas of interest, and the electromagnetic radiation has a wavelength range corresponding to a spectral absorption range of the gas of interest. 
     In another embodiment, a method is presented. The method includes irradiating a sample fluid and a reference fluid by electromagnetic radiation having a first wavelength range resulting in a first time temperature change of the sample fluid and a first time temperature change of the reference fluid, determining a first difference based upon the first time temperature change of the sample fluid and the first time temperature change of the reference fluid, irradiating the sample fluid and the reference fluid by electromagnetic radiation having a second wavelength range resulting in a second time temperature change of the sample fluid and a second time temperature change of the reference fluid, determining a second difference based upon the second time temperature change of the sample fluid and the second time temperature change of the reference fluid, monitoring and determining a concentration of a gas of interest in the sample fluid based upon the first difference and the second difference. 
     In still another embodiment, a system is presented. The system includes a first container containing a sample fluid used to determine presence of a gas of interest, a second container containing a reference fluid that does not contain a significant amount of the gas of interest, a source for producing electromagnetic radiation, an optical arrangement that splits the electromagnetic radiations into a first portion of the electromagnetic radiation and a second portion of electromagnetic radiations, and directs the first portion of the electromagnetic radiation into the sample fluid and the second portion into the reference fluid to change the temperature of the sample fluid and change the temperature of the reference fluid, a plurality of sensing devices that generate signals that are representative of the change in the temperature of the sample fluid and the change in the temperature of the reference fluid, a processing subsystem that determines the presence and concentration of the gas of interest in the sample fluid based upon a difference between the change in the temperature of the sample fluid and the change in the temperature of the reference fluid. 
     A method is presented. The method includes irradiating a sample fluid by electromagnetic radiation having a first wavelength range resulting in a first time temperature change of the sample fluid, irradiating a reference fluid by a second wavelength range resulting in a first time temperature change of the reference fluid, determining a first difference based upon the first time temperature change of the sample fluid and the first time temperature change of the reference fluid, monitoring and determining the concentration of the gas of interest in the sample fluid based upon the first difference. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, wherein: 
         FIG. 1  is a schematic view of a device for monitoring and detecting a dissolved gas or a gas of interest dissolved in a sample fluid, in accordance with an embodiment of the present systems; 
         FIG. 2  is a schematic view of another embodiment of the device of  FIG. 1  for monitoring and detecting a gas of interest dissolved in the sample fluid, in accordance with another embodiment of the present systems; 
         FIG. 3  is a flowchart of a method for determination of the existence or a non-existence of a gas of interest dissolved in the sample fluid, in accordance with one embodiment of the present techniques; 
         FIG. 4A  and  FIG. 4B  show a flowchart of a method for removing noise signals infused by environment in temperature signals or temperature change signals of a sample fluid or a reference fluid, in accordance with one embodiment of the present techniques; and 
         FIG. 5A ,  FIG. 5B ,  FIG. 5C ,  FIG. 5D ,  FIG. 5E ,  FIG. 5F ,  FIG. 5G ,  FIG. 5H  and  FIG. 5I  show a group of graphs that show a process for removal of noise signals from a signal that is representative of a difference between a change in the temperature of a sample fluid and a change in the temperature of the reference fluid, in accordance with one embodiment of the present techniques. 
     
    
    
     DETAILED DESCRIPTION 
     When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it may be about related. Accordingly, a value modified by a term such as “about” is not limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. 
     Though the present discussion provides examples in the context of an insulating fluid used in electric power industry, typically in transformers, these processes can be applied to any other fluid or application. In some embodiments, the insulating fluid may include a dielectric or insulating oil, a mineral oil, a coolant, or the like. The method and device described herein may be used with other industries such as chemical industry, petroleum industry, food industry, and water industry. Other suitable examples of the fluid may include vegetable oils, beverages, chemical compounds, or the like. 
     The present methods and systems measure and test dissolved gases in a fluid, for example transformer oil or cooling fluid. In one embodiment, the present methods and systems determine concentration of the dissolved gases in the fluid. As discussed in detail below, some of the embodiments of the present systems and methods provide for selectively detecting and monitoring dissolved gases in a fluid by using calorimetry without extracting the dissolved gases from the fluid. In one embodiment, the present systems and methods determine the concentration/quantity of dissolved gases in a substantially non-transparent fluid without extracting the dissolved gases. 
     The present systems and methods monitor a sample fluid to determine the existence or non-existence of one or more dissolved gases in a sample fluid. As used herein, the term “sample fluid” refers to a fluid that is to be monitored and tested to determine the existence or non-existence of a dissolved gas. The present systems and methods further monitor and determine the concentration of the dissolved gases in the sample fluid. The present systems and methods irradiate electromagnetic radiation into the sample fluid and a reference fluid. According to one embodiment, the reference fluid does not contain the dissolved gases. The electromagnetic radiation has wavelengths that correspond to the absorption range of the dissolved gases. In one embodiment, the intensity of the electromagnetic radiation irradiated into the sample fluid and the intensity of the electromagnetic radiation irradiated into the reference fluid is same. The irradiation of the electromagnetic radiation into the sample fluid and the reference fluid may change the temperature of the sample fluid and the reference fluid. The change in the temperatures of the sample fluid and the reference fluid is used to monitor and determine the concentration of the dissolved gases in the sample fluid. 
     A schematic of a device  10  for the detection and monitoring of dissolved gases in fluid is illustrated in  FIG. 1  according to one embodiment. The device  10  includes a first container  12  and a second container  14 . The first container  12  contains a sample fluid  16 , and the second container  14  contains a reference fluid  18 . The sample fluid  16 , for example, may contain certain dissolved gases of interest. In the presently contemplated configuration, the sample fluid  16  is monitored and tested to determine the presence or concentration of certain dissolved gases. In the presently contemplated configuration, the sample fluid  16  is shown to include certain dissolved gases  20 . In one embodiment, the reference fluid  18  does not contain or contains de minimis amount the gas of interest. It is noted that the phrase “reference fluid does not contain gas of interest” means either the reference fluid does not contain the gas of interest or contains minimal amount of the gas of interest that does not affect the spectral absorption properties of the reference fluid. In another embodiment, the reference fluid contains the gas of interest. As used herein, the term “gas of interest” is a gas dissolved in a sample fluid, wherein the sample fluid is monitored to determine the presence and in some cases the concentration of the dissolved gas in the sample fluid. Accordingly, term “a dissolved gas in the dissolved gases  20 ” and the term “gas of interest” shall be used interchangeably. Furthermore, the sample fluid  16 , in one example, is monitored to determine the concentration of the dissolved gases  20 . In one embodiment, the sample fluid  16  and the reference fluid  18  is/are substantially non-transparent. In another embodiment, the sample fluid  16  and the reference fluid  18  is/are substantially transparent. In one embodiment, the sample fluid  16  and the reference fluid  18  are substantially same, notwithstanding the reference fluid  18  does not contain the dissolved gases  20 . In another embodiment, the sample fluid and reference fluid, are substantially similar notwithstanding the reference fluid  18  does not contain the dissolved gases  20 . It is noted that the phrase “reference fluid does not contain gas of interest” means either the reference fluid does not contain the gas of interest or contains minimal amount of the gas of interest that does not affect the spectral absorption properties of the reference fluid. In certain embodiments, the sample fluid  16  and the reference fluid  18  contain the gas of interest  20 . 
     As previously noted, the first container  12  contains the sample fluid  16 , and the second container  14  contains the reference fluid  18 . The first container  12  and the second container  14  may be of any shape having a volume to contain a sufficient amount of the sample fluid  16  and the reference fluid  18 , respectively. The volumes of the containers  12 ,  14 , in one example, are as small as 1 microliter. In some instances, the volumes of the containers  12 ,  14  may be in a range from about 1 microliter to about 10 milliliters. In some specific instances, the volumes may vary from about 5 microliters to about 5 milliliters. In some specific embodiments, the containers  12 ,  14  are cylindrical in shape with a cross section area, such as, circular, polygonal, or elliptical in shape. In one embodiment, the volume and size of the second container  14  may be similar to the first container  12 . In another embodiment, the volume and size of the first container  12  may be different from the volume and size of the second container  14 . In one embodiment, as shown in  FIG. 1 , the containers  12 ,  14  may be contained by an outside container  15  that acts as an insulator for the containers  12 ,  14 , and protects the containers  12 ,  14  from the outside environment. In one embodiment, as shown in  FIG. 1 , the containers  12 ,  14  may be contained by the outside container  15  which is temperature controlled and may be used to maintain constant temperature inside it. 
     As previously noted, in the presently contemplated configuration, while the sample fluid  16  contains the dissolved gases  20 , the reference fluid  18  does not contain an appreciable amount of the dissolved gases  20 . It is noted that while the reference fluid  18  does not contain the dissolved gases  20 , it may contain one or more gases other than the dissolved gases  20 . In one embodiment, the dissolved gases  20  may be fault gases. In one embodiment, when the dissolved gases  20  are fault gases, the detection and monitoring of one or more of the dissolved gases  20  may help in detection of faults in an equipment that contains the sample fluid  16  and the fault gases  20 . As used herein, “fault gases” refers to gases liberated within equipment upon a fault in the equipment. For example, insulating materials within transformers and related equipment break down to liberate gases. The type and distribution of the liberated gases can be related to the type of electrical fault, and the rate of gas generation or liberation can indicate the severity of the electrical fault. Examples of the fault gases dissolved in the dielectric oil, generally used in transformers, may include one or more dissolved gases such as hydrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, acetylene, butane, pentane and possibly other species. 
     As shown in  FIG. 1 , the system or device  10  further includes a radiation source  22  that produces electromagnetic radiation  24  for detection and monitoring of the dissolved gases  20 . In one embodiment, the radiation source  22  may be a laser source. It is noted that while in the presently contemplated configuration, the device  10  includes a single radiation source  22 , in certain embodiments; the device  10  may include multiple radiation sources. An embodiment of the device  10  wherein a device includes multiple radiation sources is shown in  FIG. 2 . 
     According to one embodiment, the radiation source  22  produces the electromagnetic radiation  24  that has a wavelength range corresponding to the spectral absorption range of the dissolved gases  20 . Typically, a fluid may contain several dissolved gases, and in one embodiment, when the device  10  selectively monitors or detects a gas of interest in the dissolved gases  20 , the radiation source  22  produces the electromagnetic radiation  24  that has the wavelength range in the spectral absorption range of the gas of interest in the dissolved gases  20 . For example, C 2 H 2  has its fundamental absorption range between about 3200 cm −1  to about 3350 cm −1 , and CO 2  has an absorption range between about 2300 cm −1  to about 2400 cm −1 . An absorption range includes absorption lines at several wavelengths, which means that the absorption is higher at particular wavelengths in the range. Examples of particular wavelengths include about 3309.5 cm −1  for detecting C 2 H 2  and about 2325 cm −1  for detecting CO 2 , though, of course, other wavelengths may be suitable for detecting these gases or other gases. 
     In the illustrated embodiment, the device  10  further includes a beam splitter  26 , and a mirror  28 . The beam splitter  26 , for example, may be located above the first container  12 , and the mirror  28  may be located above the second container  14 . However, in one embodiment, the beam splitter  28  may be located above the second container  14 , and the mirror  28  may be located above the first container  12 . The radiation source  22  is disposed at a position to direct the electromagnetic radiation  24  onto the beam splitter  26 . In some instances, suitable optical arrangements may be used to direct the radiations  24  onto the beam splitter  26 . For example, the electromagnetic radiation  24  may be collected by an aspheric lens and collimated using a lens. 
     The radiation source  22  transmits the electromagnetic radiation  24  onto the beam splitter  22  that splits the electromagnetic radiation  24  into two portions  30 ,  32 . The two portions  30 ,  32 , for example, include a first portion of electromagnetic radiations  30 , and a second portion of electromagnetic radiation  32 . In one embodiment, the beam splitter  26  splits the electromagnetic radiation  24  in such a way that the intensity of the first portion of the electromagnetic radiation  30  is similar to the intensity of the second portion of the electromagnetic radiation  32 . It is noted that in the present techniques, the intensity of the first portion of the electromagnetic radiation  30  and the intensity of the second portion of the electromagnetic radiation  32  need not be exactly same, notwithstanding that the intensity of the first portion of the electromagnetic radiation  30  and the intensity of the second portion of the electromagnetic radiation  32  may be similar. In one embodiment, intensity in the first portion of the electromagnetic radiation  30  is substantially similar to the intensity in the second portion of the electromagnetic radiation  32  when the intensity in the first portion of the electromagnetic radiation  30  is +10% of the intensity of the second portion of the electromagnetic radiation. 
     The first portion of the electromagnetic radiation  30  is directed/irradiated into the first container  12  and the second portion of the electromagnetic radiation  32  is directed/irradiated onto a mirror  28 . The mirror  28  reflects and directs the second portion of the electromagnetic radiation  32  into the second container  14 . Therefore, the first portion of the electromagnetic radiation  24  is directed/irradiated into the first container  12  that contains the sample fluid  16 , and the second portion of the electromagnetic radiation  32  is directed into the second container  14  that contains the reference fluid  18 . In this example, the first portion of the electromagnetic radiation  30  and the second portion of the electromagnetic radiation  32  are simultaneously irradiated/directed into the sample fluid  16  and the reference fluid  18 . 
     In the presently contemplated configuration, the direction of the first portion of the electromagnetic radiation  30  into the first container  16  changes the temperature of the sample fluid  16  contained in the first container  12 . The temperature of the sample fluid  16  changes due to absorption of the first portion of the electromagnetic radiation  30  by the dissolved gases  20  and by the sample fluid  16 . In an ideal condition, since the first portion of the electromagnetic radiation  30  has the wavelength range that correspond to the spectral absorption range of the dissolved gases  20 , only the dissolved gases  20  absorb the first portion of the electromagnetic radiation  30  to change the temperature of the sample fluid  16 . In ideal conditions, when only the dissolved gases  20  in the sample fluid  16  absorb the first portion of the electromagnetic radiation  30 , the absorption of the first portion of the electromagnetic radiation  30  by the dissolved gases  20  changes the temperature of the sample fluid  16 . However, due to various factors, such as, non-transparency of the sample fluid  16 , properties of the sample fluid  16 , some of the first portion of the electromagnetic radiation  30  may be absorbed by the sample fluid  16  and by the dissolved gases  20  to change the temperature of the sample fluid  16 . Accordingly, in such conditions, the change in the temperature of the sample fluid  16  is due to the change in the temperature of the sample fluid  16  and the dissolved gases  20 . In the presently contemplated configuration, the change in the temperature is an increase in temperature. Particularly, the change in the temperature may be apparent heating up of the sample fluid  16  in the first container  12 . In some other cases, the sample fluid+dissolved gas could absorb the electromagnetic radiation and undergo some chemical change which could possibly cause a decrease in temperature. 
     Furthermore, the irradiation of the second portion of the electromagnetic radiation  32  into the second container  14  may change the temperature of the reference fluid  18  contained in the second container  14 . In ideal conditions, since the second portion of the electromagnetic radiation  32  has the wavelength range that correspond to the spectral absorption range of the dissolved gases  20 , the reference fluid  18  in the second container  14  does not absorb the second portion of the electromagnetic radiation  32 . However, due to factors, such as, non-transparency of the reference fluid  18 , properties of the reference fluid  18 , existence of gases other than the dissolved gases  20 , the reference fluid  18  and/or the gases other than the dissolved gases  20  may absorb some of the second portion of the electromagnetic radiation  32 . The absorption of the second portion of the electromagnetic radiation  32  by the reference fluid  18  and/or the gases other than the dissolved gases  20  may change the temperature of the reference fluid  18 . In the presently contemplated configuration, the change in the temperature of the reference fluid is an increase in the temperature of the reference fluid  18 . 
     In one example, the device  10  further includes one or more temperature sensors  34 ,  36  that measure the change in temperatures of the sample fluid  16  and the reference fluid  18 , respectively to generate signals  37 ,  39 . The signal  37  is representative of the change in the temperature of the sample fluid  16  and the signal  39  is representative of the change in the temperature of the reference fluid  18 . In some specific embodiment, the temperature sensors  34 ,  36  are located in the containers  12 ,  14  as shown in  FIG. 1 . One or more of the temperature sensors  34 ,  36 , for example, may be an electrical sensor or an optical sensor. In some embodiments, one or more of the temperature sensors  34 ,  36  may be a linear temperature sensor. Suitable examples of the electrical temperature sensors  34 ,  36  include thermocouples, resistive temperature detectors (for example Pt100, Pt1000), thermistors, semiconductor sensors or diodes. Some example of optical temperature sensing techniques include surface plasmon resonance (SPR), and interferometry. Criteria and tradeoffs for selecting a sensor type or types from among the available options for a given situation will be apparent to those skilled in the art. 
     Hereinafter, the term “temperature sensor  34 ” shall be referred to as “first temperature sensor  34 .” Hereinafter, the term “temperature sensor  36 ” shall be referred to as “second temperature sensor  36 .” In the presently contemplated configuration, the first temperature sensor  34  is located inside the first container  12  and the second temperature sensor  36  is located inside the second container  14 . Resolution of the temperature sensors  34 ,  36  may vary case by case. In some embodiments, the temperature sensors  34 ,  36  with high resolution, for example 20 micro kelvin may be desirable. In some embodiments, the temperature sensors  34 ,  36  with lower resolution may be sufficient for the temperature measurement. In some embodiments, the temperature sensor may have resolution between about 20 micro kelvin and about 10 kelvin. One skilled in art knows to use a suitably sensitive temperature sensor according to the expected range of the change in temperature of the fluid for a particular gas. 
     In one embodiment, the first container  12  includes the first sensor  34 , and the second container  14  includes the second sensor  36 , wherein the sensors  34 ,  36  are arranged in a differential measurement arrangement. For example, the differential measurement arrangement may be a Wheatstone bridge or any other differential measurement arrangement. The differential measurement arrangement generates signals  38  that are representative of a difference between the change in the temperature of the sample fluid  16  and the change in the temperature of the reference fluid  18  due to irradiation of the first portion of the electromagnetic radiation into the sample fluid and the second portion of the electromagnetic radiation into the reference fluid. The signals  38  that are representative of the difference between the change in the temperature of the sample fluid  16  and the change in the temperature of the reference fluid  18  may be generated based upon the signals  37 ,  39 . Accordingly, in one embodiment, when the change in temperature of the sample fluid  16  due to irradiation of the electromagnetic radiation  30  is ΔT sample  and the change in temperature of the reference fluid  18  due to irradiation of the electromagnetic radiation  32  is ΔT ref , then the differential measurement arrangement or the Wheatstone bridge generates signals  38  that are representative of the difference between the change in temperature signals of the sample fluid  14  and the reference fluid  16 , which may be represented as follows:
 
Δ T=ΔT   sample   −ΔT   ref   (1)
 
     In certain embodiments, the device  10  further includes a processing subsystem  42  that is in operational communication with the first temperature sensor  34  and the second temperature sensor  36  and the device  10 . It is noted that while in the presently contemplated configuration, the processing subsystem  42  receives the signals  38  representative of the difference between the change in temperature of the sample fluid  14  and the change in the temperature of the reference fluid  16 , in certain embodiments, the processing subsystem  42  may receive the temperatures of the sample fluid  16  and the reference fluid  18  from the sensors  34 ,  36 , and determine a difference between the change in temperature signals based upon the temperatures of the sample fluid  16  and the reference fluid  18 . 
     Irradiation of electromagnetic radiation into the sample fluid  16  and/or the reference fluid  18  may lead to absorption of the electromagnetic radiation  30 ,  32  by the sample fluid  16 , the reference fluid  18  and the dissolved gases  20 . The absorption of the electromagnetic radiation  30 ,  32  may result in conduction, convection and radiation heat gain by the sample fluid  16  and/or the reference fluid  18  to increase the temperature of the sample fluid  16  and/or the reference fluid  18 . The increase in the temperature of the sample fluid  16  and/or the reference fluid and/or the difference in temperature between the sample and reference fluids may be very small, for example, in the range of micro Kelvin (˜μK). The temperature of surrounding environment may introduce temperature error (hereinafter, referred to as noise) in the signals  38  (see  FIG. 1 ). Considering that the temperature change in the sample fluid  16  and/or the reference fluid  18  and/or the difference in temperature between the sample and reference fluids may be in the range of micro Kelvin (˜μK), the noise tends to mask the temperature change leading to inaccurate decisions on the existence and/or the concentration of the dissolved gases  20 . The noise, for example, may be in the form of drift and/or oscillations in the signals  38 . Therefore, it is advantageous to remove the noise introduced in the signals  37 ,  39 ,  38  due to the environmental effects. 
     To remove the noise signals from the signals  38 , the device  10 , may further include a plurality of environmental sensors  40 ,  44 ,  46 ,  48 ,  50 ,  52 . As used herein, the term “environmental sensors” refers to sensors that measure temperature of the nearby environment of the first container  12  and the second container  14 . In accordance with one embodiment, the environmental sensors  40 ,  44 ,  46 ,  48 ,  50 ,  52  may be located proximate the containers  12 ,  14  as shown in  FIG. 1 . The environmental sensors  40 ,  44 ,  46 ,  48 ,  50 ,  52  may be located outside the containers  12 ,  14 , and at locations other than the ones shown in  FIG. 1 . In the presently contemplated configuration, the environmental sensors  40 ,  44 ,  46  are located proximate the environment of the first container  12 . The environmental sensors  40 ,  44 ,  46  measure the temperature of nearby environment of the first container  12 . Similarly, the environmental sensors  48 ,  50 ,  52  are located in the nearby environment of the second container  14 . The environmental sensors  48 ,  50 ,  52  measure the temperature of the nearby environment of the second container  14 . The environmental sensors  40 ,  44 ,  46 ,  48 ,  50 ,  52  measure the temperature of the nearby environment of the first container  12  and the second container  14  to generate environmental temperature signals  54  that are representative of the temperatures of the nearby environment of the first container  12  and the second container  14 . 
     As shown in  FIG. 1 , the environmental sensors  40 ,  44 ,  46 ,  48 ,  50 ,  52  are in an operational communication with the processing subsystem  42 . The processing subsystem  42  receives the environmental temperature signals  54  that are representative of temperature of the nearby environment of the first container  12  and the second container  14 . The processing subsystem  42  further removes the effects of environment temperature on the change in the temperature of the sample fluid  16  and the reference fluid  18  using the environmental temperature signals  54 . In one embodiment, the processing subsystem  42  removes noise introduced in the signals  37 ,  39  before determining the concentration of the dissolved gases  20  in the sample fluid  16 . In one embodiment, the processing subsystem  42  removes noise introduced in the signal  38  before determining the concentration of the dissolved gases  20  in the sample fluid  16 . Particularly, the processing subsystem  42  eliminates drift and reduces oscillations introduced in the signals  37  and  39 , or in the difference signal  38  due to environmental temperature. The removal of the effects of the environment temperature on the signals  37 ,  38 ,  39  is explained in greater detail with reference to  FIG. 4 . 
     Subsequent to the generation of the signals  38  representative of the difference between the change in temperature of the sample fluid  16  and the change in the temperature of the reference fluid  18 , and the removal of the noise signals from the signals  38 , the processing subsystem  42  identifies, monitors and/or determines the dissolved gases  20  based upon the signals  38 . In one embodiment, the processing subsystem  42  determines the concentration of the dissolved gases  20  in the sample fluid  16  based upon the difference between the change in temperature of the sample fluid  16  and the change in the temperature of the reference fluid  18 . In another embodiment, the processing subsystem  42  determines the concentration of the dissolved gases based upon the difference between the change in temperature of the sample fluid  16 , the change of temperature of the reference fluid  18  and a calibration constant. In one embodiment, the calibration constant may be determined experimentally. In another embodiment, the calibration constant, for example, may be determined based upon the extinction coefficient of the dissolved the gas of interest, length of the first container  12 , the input intensity and the thermal resistance between the first container and the environment. The monitoring and determination of the concentration of the dissolved gases  20  in the sample fluid  16  is explained in greater detail with reference to  FIG. 3 . 
     Referring now to  FIG. 2 , a system or device  200  that includes two radiation sources  202 ,  204  is shown. The device  200 , for example, shows another embodiment of the device  10  referred to in  FIG. 1 . In the presently contemplated configuration, the device  200  includes the first radiation source  202  and the second radiation source  204 . The first radiation source  202  and the second radiation source  204 , for example, may be similar to the radiation source  22  (see  FIG. 1 ). A variety of radiation sources  22 ,  202 ,  204  (see  FIG. 1  and  FIG. 2 ) may be used, including ionizing and non-ionizing radiation sources, which may emit coherent radiation. The radiation sources  22 ,  202 ,  204  may emit radiation having wavelength in a range from near infra-red to mid infrared region. Suitable examples may include thermal radiation sources, LED sources, MEMS sources, and incandescent lamps. In one embodiment, the radiation sources  22 ,  202 ,  204  is a laser source that is monochromatic, and provides a narrow wavelength band sometimes referred to as a coherent electromagnetic field. In some instances, a tunable diode laser (TDL) may be used as it can be tuned or set to produce radiation at individual wavelengths to detect and monitor several gases individually in the fluid. In addition, the TDL can also be set to produce and monitor different absorption lines for the same gas for confirmation and accuracy. In some instances, a quantum cascade laser (QCL) can be used as the source due to its ability to produce radiation of wavelengths in the mid IR range, and due to its tunable nature and its narrow line width can be used to monitor the hyperfine lines in the gas spectrum. 
     In the presently illustrated configuration, the first radiation source  202  and the second radiation source  204  produce electromagnetic radiation  206 ,  208 , respectively, having wavelengths that correspond to the spectral absorption range of the dissolved gases  20  in the sample fluid  16 . In one embodiment, when a gas of interest in the dissolved gases  20  is monitored, or when a concentration of the gas is determined, the first radiation source  202  and the second radiation source  204  may produce the electromagnetic radiation  206 ,  208  that have wavelengths within an absorption range of the gas of interest in the dissolved gases  20 . 
     The first radiation source  202 , for example, may be located at a position, such that the first radiation source  202  directs the electromagnetic radiation  206  into the sample fluid  16  in the first container  12 . Similarly, the second radiation source  204  may be located at a position such that the electromagnetic radiation  208  is directed into the reference fluid  18  in the second container  14 . It is noted that in the presently contemplated configuration, the device  200  does not include the beam splitter  26  and the mirror  28  referred to in  FIG. 1  due to the existence of the two radiation sources  202 ,  204  that transmit the electromagnetic radiation  206 ,  208  into the first container  12  and the second container  14 , respectively. In one embodiment, the device  200  may include suitable optical arrangements  210 ,  212  to direct the electromagnetic radiation  206 ,  208  into the first container  12  and the second container  14 , respectively. The optical arrangements or elements can be used to filter, collimate or otherwise condition the electromagnetic radiation  206 ,  208  from the radiation sources  202 ,  204 . The first radiation source  202  transmits electromagnetic radiation  206  into the first container  12 , and the second radiation source  202  transmits electromagnetic radiation  208  into the second container  14 . In one embodiment, the intensity of the electromagnetic radiation  206  is similar to the intensity of the electromagnetic radiation  208 . The rest of the components and functionalities of the device  200  in  FIG. 2  remains similar to the components and functionalities of the device  10  explained with reference to  FIG. 1 . 
     Referring now to  FIG. 3 , a flowchart of a method  300  for determination of the existence or non-existence of a gas of interest dissolved in a sample fluid is explained in accordance with one embodiment of the present techniques. The sample fluid, for example, may be the sample fluid  16  referred to in  FIG. 1 . In the presently contemplated configuration, the sample fluid is tested to determine the presence and concentration (if present) of the gas of interest in the sample fluid. As previously noted with reference to  FIG. 1 , the term “gas of interest” refers to a gas dissolved in a sample fluid, wherein the sample fluid is monitored to determine the existence or non-existence, and concentration of the gas dissolved in the sample fluid. As shown in  FIG. 3 , at  302 , the sample fluid is filled in the first container  12  (see  FIG. 1 ). In the presently contemplated configuration, the sample fluid is oil. The sample fluid may or may not contain the gas of interest. The gas of interest, for example, may be one of the dissolved gases  20  (see  FIG. 1 ). 
     Further, at  304 , a reference fluid is filled in the second container  14 . In the presently contemplated configuration, the reference fluid is oil. In one embodiment, the reference fluid is substantially same as the sample fluid. In another embodiment, the reference fluid is substantially similar to the sample fluid. It is noted that notwithstanding the reference fluid being substantially same as the sample fluid or being substantially similar to the sample fluid, the reference fluid does not contain the gas of interest. In one embodiment, the reference fluid may contain the gas of interest. 
     At  306 , electromagnetic radiation that has a first wavelength range are directed into the sample fluid and the reference fluid. In one example, the first wavelength range includes wavelengths of the electromagnetic radiation that correspond to spectral absorption peak of the gas of interest. The first wavelength range, for example, may be determined based upon the specific gas absorption spectral databases or experimentally by using absorption spectroscopy. For example, for a gas of interest CO, one spectral absorption peak is at 2150.8 cm −1  and a spectral absorption valley is at 2152.6 cm −1 . Hereinafter, the electromagnetic radiation that has the first wavelength range will be referred to as EMR λ max . It is noted that while a first portion of the EMR λ max  is irradiated into the sample fluid and a second portion of the EMR λ max  is irradiated into the reference fluid, for ease of understanding the discussion hereinafter will refer to irradiation of both fluid by the EMR λ max , and shall not refer to the irradiation of the first portion of the EMR λ max  and the second portion of the EMR λ max . 
     As previously noted with reference to  FIG. 1 , the irradiation EMR λ max  may result in an increase in the temperature of the sample fluid and the reference fluid. In some embodiments, when the sample fluid is substantially transparent and does not contain the gas of interest, the EMR λ max  may not be absorbed by the sample fluid, and therefore does not change the temperature of the sample fluid. Therefore, in certain embodiments, the change in temperature of the sample fluid due to the irradiation of the electromagnetic radiation λ max  may be approximately zero. When the change in the temperature of the sample fluid is zero, it may  G □ □     □ fluid does not contain a sufficient level of Similarly, in certain embodiments, when the reference fluid is substantially transparent, the EMR λ max  may not be absorbed by the reference fluid, and therefore, the change in the temperature of the reference fluid is approximately zero. In alternative embodiments, when the sample fluid is substantially non-transparent, and the sample fluid contains the gas of interest, the EMR λ max  is absorbed by the sample fluid and the gas of interest to change the temperature of the sample fluid. Similarly, when the reference fluid is substantially non-transparent, some of the EMR λ max  is absorbed by the reference fluid to change the temperature of the reference fluid. In certain alternative embodiments, when the sample fluid is substantially non-transparent and the sample fluid does not contain the gas of interest, the sample fluid may absorb some of the EMR λ max  to change the temperature of the sample fluid. 
     The phrase “change in the temperature of the sample fluid due to irradiation of the EMR λ max ” hereinafter shall be interchangeably used with the phrase “first time temperature change of the sample fluid”. Similarly, hereinafter, the phrase “change in the temperature of the reference fluid due to irradiation of the EMR λ max ” shall be interchangeably used with the phrase “first time temperature change of the reference fluid”. Subsequently at  308 , signals that are representative of a difference between the change in temperature of the sample fluid and the change in temperature of the reference fluid due to irradiation of the EMR λ max  are generated. In other words, signals that are representative of a difference between the first time temperature change of the sample fluid and the first time temperature change of the reference fluid are generated. The signals, for example may be the signals  38  (see  FIG. 1 ). In one embodiment, signals that are representative of the difference between the change in temperature of the sample fluid and the change in the temperature of the reference fluid are generated by a differential arrangement of the first container and the second container based upon the temperature detected by the sensors  34 ,  36  (see  FIG. 1 ). In another embodiment, the signals that are representative of a difference between the change in temperature of the sample fluid and the change in the temperature of the reference fluid is determined by the processing subsystem  42  based upon the signals generated by the sensors  34 ,  36  (see  FIG. 1 ). Hereinafter, the phrase “the difference between the change in temperature of the sample fluid and the change in the temperature of the reference fluid due to irradiation of the EMR λ max ” will be referred to as first difference. The first difference for, example, may be represented by the following equation (2):
 
Δ T   1   =ΔT   sample(1)   −ΔT   ref(1)   (2)
 
where ΔT 1  is a first difference, ΔT sample(1)  is the first time temperature change of the sample fluid, ΔT ref(1)  is the first time temperature change of the reference fluid. In one embodiment, the first difference may be represented by the following equation (3):
 
Δ T   1 =(Δ T   sample(1)   −ΔT   ref(1) )˜exp(−β ref-oil   L   ref )−exp(−(α gas   c   gas +β sample-oil ) L   sample )   (3)
 
wherein α gas  refers to an extinction coefficient of a gas of interest, c gas  represents the concentration of the gas of interest in the sample fluid, β sample-oil  represents absorption coefficient of the sample fluid, β ref-oil  represents absorption coefficient of the reference fluid, L sample  represents length of path of the EMR λ max  into the first container  12 , and L ref  represents length of path of the EMR λ max  into the second container  14 .
 
     It is noted that the ΔT sample(1)  and the ΔT ref(1) , the difference ΔT 1  may be processed to remove noise introduced due to environment temperature before determination of the first difference ΔT 1 . The noise, for example, may be removed based upon signals, such as, the signals  54  (see  FIG. 1 ). The removal of noise from ΔT sample(1)  and the ΔT ref(1)  is explained in greater detail with reference to  FIG. 4 . 
     At  310 , electromagnetic radiation that has a second wavelength range is directed into the sample fluid and the reference fluid. The second wavelength range includes wavelengths of the electromagnetic radiation that correspond to spectral absorption valley of the gas of interest, if present in the sample fluid. For example, for a gas of interest CO, one spectral absorption peak (EMR λ max ) is at 2150.8 cm −1  and a spectral absorption valley (EMR λ min ) is at 2152.6 cm −1 . In another example, for the gas of interest CO, another spectral absorption peak (EMR λ max ) is at 2193.3 cm −1  and another spectral absorption valley (EMR λ min ) is at 2195 cm −1 . A person skilled in the art can identify one or more spectral absorption peaks and one more spectral absorption valleys corresponding to each gas of interest. The second wavelength range, for example, may be determined based upon gas absorption spectral database or experimentally using absorption spectroscopy. Hereinafter, the electromagnetic radiation that has the second wavelength range will be referred to as EMR λ min . Accordingly, irrespective of the sample fluid and reference fluid being transparent or non-transparent, the gas of interest if present in the sample fluid will not absorb or absorb a substantially minimal amount of the EMR λ min . 
     It is noted that the irradiation of the EMR λ min  may result in an increase in the temperature of the sample fluid and the reference fluid. In some embodiments, when the sample fluid and the reference fluid are substantially transparent (irrespective of the presence or absence of the gas of interest in the sample fluid), the EMR λ min  may not be absorbed by the sample fluid, and therefore does not change the temperature of the sample fluid. Therefore, in certain embodiments, the change in temperature of the sample fluid and the reference fluid due to the irradiation of the electromagnetic radiation EMR λ min  may be approximately zero. In alternative embodiments, when the sample fluid and the reference fluid are substantially non-transparent (irrespective of the presence or absence of the gas of interest in the sample fluid), the EMR λ min  is absorbed by the sample fluid and the reference fluid resulting in a change in the temperature of the sample fluid and the reference fluid, respectively. 
     Subsequently at  312 , signals that are representative of a difference between the change in temperature of the sample fluid and the change in temperature of the reference fluid due to irradiation of the EMR λ min  are generated. The signals, for example may be the signals  38  (see  FIG. 1 ). In one embodiment, signals that are representative of a difference between the change in temperature of the sample fluid and the change in temperature of the reference fluid due to irradiation of the EMR λ min  are generated by a differential measurement arrangement of the first container and the second container (see description in  FIG. 1 ). In another embodiment, the signals that are representative of a difference between the change in temperature of the sample fluid and the change in temperature of the reference fluid due to irradiation of the EMR λ min  are determined by the processing subsystem. The phrase “change in the temperature of the sample fluid due to irradiation of the EMR λ min ” hereinafter shall be interchangeably used with the phrase “second time temperature change of the sample fluid”. Similarly, hereinafter, the phrase “change in the temperature of the reference fluid due to irradiation of the EMR λ min ” shall be interchangeably used with the phrase “second time temperature change of the reference fluid”. Hereinafter, the phrase “the difference between the change in temperature of the sample fluid and the change in the temperature of the reference fluid due to irradiation of the EMR λ min  will be referred to as a second difference. The second difference, for example may be represented by the following equation (4):
 
Δ T   2   =ΔT   sample(2)   −ΔT   ref(2)   (4)
 
where ΔT 2  is a second difference, ΔT sample(2)  is a second time temperature change of the sample fluid, and the reference fluid, ΔT ref(2)  is a second time temperature change of the reference fluid due to irradiation of the EMR λ min . In one embodiment, the second difference may be represented by the following equation (5):
 
Δ T   2 =(Δ T   sample(2)   −ΔT   ref(2) )˜exp(˜β ref-oil   L   ref )−exp(β sample-oil ) L   sample   (5)
 
     wherein α gas  refers to an extinction coefficient of a gas of interest, c gas  represents the concentration of the gas of interest in the sample fluid, β sample-oil  represents absorption coefficient of the sample fluid, β ref-oil  represents absorption coefficient of the reference fluid, L sample  represents length of path of the EMR λ min  into the first container  12 , and L ref  represents length of path of the EMR λ min  into the second container  14 . It is noted that the second time temperature change of the sample fluid ΔT sample(2)  and the second time temperature change of the reference fluid ΔT ref(2) , the first difference ΔT 1 , or the second difference ΔT 2  may be processed to remove noise introduced due to environmental temperature before determination of the second difference ΔT 2 . The noise, for example, may be removed based upon signals, such as, the signals  54  (see  FIG. 1 ). The removal of noise from second time temperature change of the sample fluid ΔT sample(2)  and the second time temperature change of the reference fluid ΔT ref(2)  is explained in greater detail with reference to  FIG. 4 . 
     At  314 , a third difference may be determined by subtracting the second difference from the first difference. The third difference may be represented by the following equation (6):
 
Δ T   3 =(Δ T   1   −ΔT   2 )˜(exp(−(α gas   c   gas +β sample-oil ) L   sample )−exp(−β sample-oil ) L   sample ))   (6)
 
     Furthermore, at  316 , the concentration of the gas of interest c gas  in the sample fluid may be determined based upon the third difference. The concentration of the gas of interest, for example, may be determined using the following equation (7):
 
Δ T   3 −(Δ T   1   −ΔT   2 )˜α gas   c   gas   L   sample   ˜c   gas   (7)
 
     In view of the equation (7) it is noted that the concentration of the gas of interest may be determined based upon the first difference, second difference, the extinction coefficient of the gas of interest and the length of the first container. 
     It is also noted that while  FIG. 3  shows irradiation of the sample fluid and the reference fluid by the electromagnetic radiation EMR λ max  and EMR λ min , in certain embodiments when the sample fluid is substantially same as the reference fluid, and L sample =L ref =L, the sample fluid and the reference fluid may be irradiated only once by the EMR λ max  and the difference between the change in the temperature of the sample fluid and the reference fluid due to irradiation of the EMR λ max  may be used to monitor the gas of interest. For example, the concentration of the gas of interest by irradiating only EMR λ max  in the sample fluid and the reference fluid with a precondition that the sample fluid is to the same as the reference fluid may be determined using the following equation (8)
 
Δ T   4 ˜α gas   c   gas   L   (8)
 
wherein ΔT 4  is a difference between the change in the temperature of the sample fluid and the change in temperature of the reference fluid due to irradiation of the EMR λ max . Accordingly, in one embodiment, when the sample fluid is the same as the reference fluid (notwithstanding that the reference fluid does not contain the gas of interest), the concentration of the gas of interest may be determined based upon the difference between the change in the temperature of the sample fluid and the change in the temperature of the reference fluid due to irradiation of the EMR λ max , an extinction coefficient of the gas of interest and the length of the container that contains the sample fluid.
 
     It is further noted that in certain embodiments, a sample fluid is similar to a reference fluid (irrespective of the presence or absence of the gas of interest in the reference fluid). In such embodiment, when the sample fluid is similar to the reference fluid, the sample fluid is irradiated by electromagnetic radiation that has a first wavelength range, and the reference fluid is irradiated by electromagnetic radiation that has a second wavelength range. In one embodiment, the sample fluid is similar to the reference fluid when the absorbance of the reference fluid is within ±10% of the absorbance of the sample fluid in the measurement wavelength range. As previously noted, the first wavelength range corresponds to a spectral absorption peak (λ max ) of the gas of interest, and the second wavelength range corresponds to a spectral absorption valley (λ min ) of the gas of interest. The irradiation of the first wavelength range (λ max ) results in a first time temperature change of the sample fluid, and the irradiation of the second wavelength range results in a first time temperature change of the reference fluid. A first difference between the first time temperature of the sample fluid and the first time temperature change of the second fluid is determined/generated. Furthermore, the second wavelength range (λ min ) is irradiated into the sample fluid and the reference fluid. The irradiation of the second wavelength range results in a second time temperature change of the sample fluid and a second time temperature of the reference fluid. A second difference between the second time temperature change of the sample fluid and a second time temperature change of the reference fluid is determined. The first difference and the second difference is used to monitor the gas of interest and determine a concentration of the gas of interest. 
       FIG. 4  is a flowchart of a method  400  for removing noise introduced in a temperature signal or a change in the temperature signal of a sample fluid or a reference fluid due to environment temperature, in accordance with one embodiment of the present techniques. In one embodiment, the method  400  may be used to remove noise from the signal  38  (see  FIG. 1 ) that is representative of the difference in the change in the temperatures of the sample fluid  16  and the reference fluid  18 . In one embodiment, the noise may be removed by the processing subsystem  42  (see  FIG. 1 ). 
     In the presently contemplated configuration, reference numeral  402  is representative of a signal that represents a difference in a change in the temperatures of a reference fluid and a sample fluid. For example, the signal  402  is the signal  38  (see  FIG. 1 ). In certain embodiments, the signal  402  may be a signal representation of the first time temperature change of the sample fluid ΔT sample(1) , the first time temperature change of the reference fluid ΔT ref(1) , a first difference ΔT 1 , the second time temperature change of the sample fluid ΔT sample(2) , the second time temperature change of the reference fluid ΔT ref(2)  and the second difference ΔT 2 , as referred to in  FIG. 3 . The signal  402 , for example, may be a signal  502  as shown in  FIG. 5 . 
     At  404 , a start point p start  and an end point p end  are located to identify a trend change in the temperature of the signal  402 . The start point p start  and an end point p end , for example, may be identified using a wavelet decomposition technique. Exemplary start point p start    504  and end point p end    506  in the signal  502  are shown in  FIG. 5 . The signal  502  shows a change in temperature of a sample fluid at different time stamps. As shown in the signal  502 , the temperature of the sample fluid starts increasing at the start point p start    504 , and the temperature starts decreasing at the end point p end    506 . 
     Referring back to  FIG. 4 , at  406 , a baseline signal y base  may be determined based upon the signal  402 , the start point p start  and the end point p end . Particularly, the baseline signal y base  is generated by removing data points from the signal  402  that fall after the start point p start  and before the end point p end . In other words, the baseline signal y base  is generated by removing the data points that show a change in temperature in the signal  402 . For example, as shown in  FIG. 5 , a baseline signal y base  corresponding to the signal  502  is generated by removing data points that fall in a region  507  after the start point p start  and before the end point p end . In one embodiment, the baseline signal y base  may be represented by the following equation (9):
 
 y   base   =y (1| p   start   ,p   end |end)  (9)
 
wherein y is the signal  402 ,  502 , y base  is a baseline signal corresponding to the temperature change signal y, p start  is a start point in the temperature change signal, p end . is an end point in the temperature change signal y.
 
     Referring back to  FIG. 4 , at  410  a combined signal X is generated based upon a plurality of environmental temperature signals  408  and the baseline signal y base . Particularly, the combined signal X is generated by combining the environmental temperature signals  408  such that the base of the combined signal matches the baseline signal y base . The combined signal X, for example, may be generated by applying linear regression on the environmental signals  408  to match the baseline signal y base . The environmental temperature signals  408 , for example, may be generated by the sensors  44 ,  46 ,  48 ,  50 ,  52  referred to in  FIG. 1 . 
     Subsequently at  412 , a baseline trend signal is generated by applying a wavelet decomposition method to the combined signal X. An exemplary baseline trend signal  509  corresponding to the environmental signals  408  is shown in  FIG. 5 . Furthermore, at  414 , an intermediate signal is generated based upon the baseline trend signal and the change in temperature signal  402 . The intermediate signal, for example is generated by subtracting the baseline trend signal from the signal  402 . For example, in  FIG. 5  an intermediate signal  510  is generated by subtracting the baseline trend signal  509  from the signal  502 . It is noted that subtraction of the baseline trend signal  509  from the signal  502  removes drift  512  from the signal  502  to generate the intermediate signal  510 . The drift  512 , for example, is a long term error introduced in the change in temperature signal  502  due to environment temperature. 
     Referring back to  FIG. 4 , at  415  a wavelet decomposition technique is applied to a portion of the intermediate signal to generate an approximate signal. Particularly, wavelet decomposition is applied to a portion of the intermediate signal that lies between the start point p start  and the end point p end . For, example, in  FIG. 5 , wavelet decomposition is applied to a portion of the intermediate signal  510  that lies between the start point p start  and the end point p end  to generate an approximate signal  511 . 
     Subsequently, at  416 , oscillations trend is determined based upon the intermediate and the approximate signal. For example, the oscillations trend is determined by subtracting the approximate signal from the intermediate signal. The oscillations trend represents short term or local variability in the signal  402 , therefore the oscillations trend is also present in the intermediate signal, due to the environment temperature. An exemplary oscillations trend  514  corresponding to the intermediate signal  510  and the approximate signal  511  is shown in  FIG. 5 . 
     Furthermore, at  417 , an environmental oscillations signal is determined based upon the combined signal X and the baseline trend signal. For example, the environmental oscillations signal is generated by subtracting the baseline trend signal from the combined signal X. An exemplary environmental oscillations signal  515  is shown in  FIG. 5 . 
     Subsequently, at  418 , a residual signal is generated by filtering the oscillations trend signal using the environmental oscillations signal. For example, in  FIG. 5 , a residual signal is generated by filtering the oscillations trend signal  514  using the environmental oscillations signal  515 . Furthermore at  420 , the residual signal and the approximate signal are combined to generate a final signal. The final signal contains minimal noise due to drift and oscillations. An exemplary final signal  516  that is generated by removing drift and oscillations from the temperatures change signal  502  is shown in  FIG. 5 . 
     In certain embodiments, white noise may be removed from the final signal at  422  by using various techniques, such as, average filtering method, moving average filtering method, and the like. In this example, the removal of the white noise from the final signal results in generation of a white noise corrected final signal. An exemplary white noise corrected signal  518  that is generated by using a moving average filtering technique on the final signal  516  is shown in  FIG. 5 . 
     Subsequently, in certain embodiments, at  424  a noise corrected signal may be generated. The noise corrected, for example, may be generated by fitting a curve on the white noise corrected final signal. For example, in  FIG. 5 , a curve is fitted on the white noise corrected signal  518  to generate a noise corrected signal  520 . The noise corrected signal, for example, may be used to monitor and determine concentration of a gas of interest in a sample fluid. 
     The present systems and techniques provide a direct (in-oil/fluid) approach for monitoring dissolved gases in a fluid without extracting gases from the fluid unlike known methods and devices. The present systems and techniques selectively determine individual gases and their concentrations in the fluid, for example in dielectric oils used in transformers. Furthermore, the present systems and techniques monitor and determine the concentration of the dissolved gases even when the dissolved gases are dissolved in a substantially non-transparent fluid. The device explained with reference to  FIG. 1  is small and compact in one embodiment, and thus is suitable for use on-site. In other words, the device is field deployable, and can be employed near a system such as transformer for periodic gas detection analysis. 
     While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.