Abstract:
A measuring system places a plurality of sensor arrays in a lateral enclosure, the sensors being able to measure movement of magnetic floats from which a liquid level can be calculated. The plurality of sensor arrays is serially positioned in the lateral enclosure in order to enable monitoring of the entire lateral enclosure. The plurality of sensor arrays uses a circuit board with a plurality of a Hall-Effect sensors and a microcontroller to detect the magnetic floats. The circuit boards are also provided with male and female interconnectors to allow an arbitrary sensor array to be connected to an adjacent sensor array; through these connections each of the plurality of sensor arrays is grouped and in combination able to monitor the entire area of the lateral enclosure. A segmented construction for the lateral enclosure is also possible, with each segment containing one of the sensor arrays.

Description:
[0001]    The current application claims a priority to the U.S. Provisional Patent application Ser. No. 61/821,364 filed on May 9, 2013 and to the U.S. Provisional Patent application Ser. No. 61/870,893 filed on Aug. 28, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to a design of a segmented and configurable sensor apparatus to accurately measure the level of a liquid or liquids within a fixed storage tank. Such applications include the measurement of oil and water in storage tanks used in the petroleum industry or other applications such as municipal water systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    Current technologies utilize three methods to measure liquids in petroleum tanks: dipsticks (which measures a liquid level through a human operator), radar (which measures the liquid level by measuring the distance between the transmitter and the surface of the liquid within the tank), and various forms of floats (which measures the liquid level by proportionately changing the electrical resistance of a variable resistor or resistor divider). 
         [0004]    Each of these techniques has advantages and disadvantages. The manual method using a dipstick involves significant cost for the human operator and the inability to monitor levels on a real time or quasi-real time basis. There is also the possibility of measurement error inherent with dipstick measurements. The radar method is expensive, typically cannot differentiate between different types of liquid, such as oil and water. While in theory, the accuracy of radar can be excellent, and in practice, these radar systems have not proven to be sufficiently accurate or reliable. Systems utilizing floats have used traditional analog technology to vary the value of a resistor or a potentiometer based on the position of the float. Such systems have several advantages: low cost, simple, reasonable accuracy, and reliable. Traditional systems utilizing floats also have many disadvantages: They require medium to high power to operate due to the low impedances involved, they cannot interpolate readings to obtain higher accuracy, they require subsequent signal processing to interface with computer monitoring and control systems, the resistance elements can vary with temperature affecting accuracy, and they are subject to noise and interference due to the analog technology employed. 
         [0005]    Therefore, the objective of the present invention is to provide a unique and novel design that overcomes many of the disadvantages of traditional float-based systems. The present invention&#39;s use of digital Hall Effect sensors, microcontrollers, software, and advanced float designs is central to the novel design described hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic overview of the present invention without the magnetic floats. 
           [0007]      FIG. 2  is a schematic overview of the present invention with the magnetic floats. 
           [0008]      FIG. 3  is a schematic overview of one sensor array for the present invention. 
           [0009]      FIG. 4  is a schematic overview of two sensor arrays interlocking with each other. 
           [0010]      FIG. 5  is a schematic overview for a segmented portion in one embodiment of the present invention. 
           [0011]      FIG. 6  is a top schematic overview for the segmented portion. 
           [0012]      FIG. 7  is a bottom schematic overview for the segmented portion. 
           [0013]      FIG. 8  is a schematic overview of two segmented portions interlocking with each other. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention. 
         [0015]    As can be seen in  FIGS. 1 and 2 , the present invention is a system for measuring a liquid surface level within a storage tank. The present invention must be positioned plumb within the storage tank in order to receive an accurate liquid level reading. The present invention mainly comprises a lateral enclosure  1 , a plurality of sensor arrays  2 , at least one magnetic float  12 , and a central controller  13 . The lateral enclosure  1  is used to surround and to protect the internal components of the present invention from the contents of the storage tank. The lateral enclosure  1  is designed for exposure to liquids at high temperature and needs to be made of a non-magnetic material. The magnetic float  12  is exteriorly positioned around and is slidably engaged to the lateral enclosure  1 , which allows the movement of the magnetic float  12  to be up and down the lateral enclosure  1 . The height of the magnetic float  12  indicates the liquid surface level within the storage tank because the magnetic float  12  will be buoyant upon the liquid held within the storage tank. The vertical position of the magnetic float  12  is detected by the plurality of sensor arrays  2 , which are serially mounted within the lateral enclosure  1 . 
         [0016]    The serial positioning of the plurality of sensor arrays  2  allows the present invention to detect the magnetic float  12  anywhere along the lateral enclosure  1 . Moreover, the lateral enclosure  1  needs to be cross-sectionally shaped in such a way to prevent the magnetic float  12  from rotating about the lateral enclosure  1  because the orientation of the magnetic field from the magnetic float  12  in relation to the plurality of sensor arrays  2  is important to receiving accurate measurement readings. Each of the plurality of sensor arrays  2  is a set of electronic components, which means the lateral enclosure  1  must provide a liquid-tight seal against the contents of the storage tank. In addition, each of the plurality of sensor arrays  2  is made at the same portable size so that the plurality of sensor arrays  2  can be easily transported to the location of the storage tank and can be easily assembled to accommodate the appropriate height within the storage tank. Thus, the plurality of sensor arrays  2  is designed to be daisy-chained together. In the preferred embodiment of the present invention, each of the plurality of sensor arrays  2  is sized to measure one foot of length. 
         [0017]    The plurality of sensor arrays  2  is designed to communicate with each other and to detect their surroundings along the entire length of the present invention. Consequently, each of the plurality of sensor arrays  2  comprises a circuit board  3 , a plurality of Hall-Effect sensors  6 , a microcontroller  7 , a temperature sensor  8 , a regulator  9 , a male interconnector  10 , and a female interconnector  11 , all of which are shown in  FIG. 3 . The circuit board  3  is used as a mounting board for the electronic components of each sensor array  2 . Each of the plurality of Hall-Effect sensors  6  is a transducer that varies its output voltage in response to a magnetic field, which is produced by the magnetic float  12  in the present invention. Thus, the plurality of Hall-Effect sensors  6  is serially mounted onto the circuit board  3  and is aligned to be along the longitudinal enclosure so that one of the Hall-Effect sensors  6  will be triggered if the magnetic float  12  travels within the vicinity of that particular sensor array. In addition, the plurality of Hall-Effect sensors  6  is systematically spaced apart from each other by a set interval  14  on the circuit board  3 , which allows the present invention to accurately identify the position of the magnetic float  12  along the height of that particular sensor array. The plurality of Hall-Effect sensors  6  is capable of a resolution of half of the set interval  14  because two of the Hall-Effect sensors  6  will be triggered if the magnetic float  12  is located between a pair on Hall-Effect sensors  6  for that particular sensor array. In the preferred embodiment of the present invention, each of the plurality of sensor arrays  2  has 24 Hall-Effect sensors  6  that are serially spaced apart from each other by a set interval  14  of 0.5 inches. In addition, the microcontroller  7  is electrically connected to each of the plurality of Hall-Effect sensors  6  so that the microcontroller  7  is able to receive and process a detection signal from any of the Hall-Effect sensors  6 . The microcontroller  7  is also converts an analog detection signal into a digital detection signal that can be interpreted by the central controller  13 , which is used to receive and process data from the plurality of sensor arrays  2 . Thus, the microcontroller  7  for each of the sensor arrays  2  is communicably coupled to the central controller  13 . The microcontroller  7  is also a low power device, which improves the energy efficiency of each of the sensor arrays  2 . 
         [0018]    The microcontroller  7  is able to manage other functions and processes for some of the other components in a sensor array  2 . The temperature sensor  8  is used to measure the temperature of the liquid held within the storage tank, which allows the present invention to measure the temperature gradient along the entire height of the storage tank through the plurality of sensor arrays  2 . Consequently, the temperature sensor  8  is mounted onto the circuit board  3  and is electronically connected to the microcontroller  7  so that the central controller  13  is able to receive the temperature reading from the location of each of the sensor arrays  2 . In addition, the regulator  9  is used to maintain proper voltage levels for an analog detection signal being sent from one of the Hall-Effect sensors  6  to the microprocessor. Consequently, the regulator  9  is mounted onto the circuit board  3 , and the microcontroller  7  is electronically connected to each of the plurality of Hall-Effect sensors  6  through the regulator  9 . In the preferred embodiment of the present invention, the regulator  9  is a 2.5-volt regulator  9 . Furthermore, the male interconnector  10  and the female interconnector  11  provide the means to daisy-chain the plurality of sensor arrays  2  together, which is shown in  FIG. 4 . In order to daisy-chain the plurality of sensor arrays  2 , the male interconnector  10  and the female interconnector  11  are mounted onto the circuit board  3 , opposite to each other. This way the male interconnector  10  of an arbitrary sensor array  101  can electronically engage the female interconnector  11  of the adjacent sensor array  102 . 
         [0019]    In the preferred embodiment of the present invention, the male interconnector  10  is a 5-pin connector, and the female interconnector  11  is a 5-pin receiver, where the 5-pins consist of: the power (+3.3 Volts), the ground, the inter-integrated circuit (I2C) bus data, the I2C bus clock, and the digital notification signal. The 3.3-volt power and the ground rails are used to electrically power each of the sensor arrays  2 . The I2C bus data and the I2C bus clock rails are used to as a communication link between the sensor arrays  2  and the central controller  13 . The digital notification signal rail is used to alert the central controller  13  of a positional change in the magnetic float  12 . Also in the preferred embodiment, the typical maximum number of sensor arrays that can be daisy-chained together is 32, but a larger number of daisy-chained sensor arrays could be possible through the use of bus repeaters. 
         [0020]    During manufacture, the microcontroller  7  is programmed with a boot loader, application software, and a section number starting at the bottom. For example, the bottom sensor array for a 22 foot sensor array would be numbered 1, while the top sensor array would be numbered 22, and all sensor arrays in between would be sequentially numbered. The boot loader would allow the application software to be upgraded in the field. 
         [0021]    As can be seen in  FIG. 2 , the present invention can be configured to accommodate a storage tank that contains a number of different liquids such as a three-phase separator. Thus, the present invention would need to comprise a plurality of magnetic floats  12 , each of which has a different buoyancy weight for a specific kind of liquid. For example, the three-phase separator contains crude oil, an oil-water emulsion, and pure water. Thus, the present invention would use one magnetic float  12  for the surface level of the crude oil, another magnetic float  12  for the surface level of the oil-water emulsion, and another magnetic float  12  for the surface level of the water. These magnetic floats  12  are “tuned” to maintain neutral buoyancy in liquids of specific gravities of crude oil, an oil-water emulsion, and pure water. By making differential measurements between these magnetic floats  12 , the depth of each liquid layer can be calculated with precision. Once the depth of each layer is known, the amount of each liquid may be easily calculated based on the known dimensions of the storage tank. 
         [0022]    The present invention has a non-segmented embodiment and a segmented embodiment. In the non-segmented embodiment, the primary feature is that the lateral enclosure  1  is non-segmented or is one continuous piece of tubing. This embodiment of the present invention further comprises a top cap  18  and a bottom cap  19 , which are used to create a liquid-tight seal at both the top and bottom openings of the lateral enclosure  1 . Thus, the top cap  18  is positioned adjacent and perimetrically connected to the lateral enclosure  1 . In addition, the bottom cap  19  is positioned adjacent to the lateral enclosure  1  opposite to the top cap  18  and is perimetrically connected to the lateral enclosure  1 . The combination of the top cap  18 , the bottom cap  19 , and the lateral enclosure  1  forms a liquid-tight enclosure for the plurality of sensor arrays  2 . For the non-segmented embodiment, the first Hall-Effect sensor  301  and the last Hall-Effect sensor  302  on each of the sensor arrays  2  has a specific configuration in order to properly identify the positioning of the magnetic float  12  in between a pair of sensor arrays. The first Hall-Effect sensor  301  is only offset from the top board edge  4  of the circuit board  3  by half of the set interval  14 , and the last Hall-Effect sensor  302  is only offset from the bottom board edge  5  of the circuit board  3  by half of the set interval  14 . In the preferred embodiment, the set interval  14  is 0.5 inches, which means that the first Hall-Effect sensor  301  is offset from the top board edge  4  by 0.25 inches and that the last Hall-Effect sensor  302  is offset from the bottom board edge  5  by 0.25 inches. 
         [0023]    In the segmented embodiment illustrated in  FIGS. 5 ,  6 , and  7 , the primary feature is that the lateral enclosure  1  is a plurality segmented portions  15 , each of which has a corresponding sensor array  401  from the plurality of sensor arrays  2 . The plurality of segmented portions  15  is serially interlocked with each other, and the number of segmented portions  15  that need to be serially interlocked depends on the height of the storage tank. Each of the plurality of segmented portions  15  comprises a top rim  16  and a bottom rim  17 , which delineate opposite openings for each segmented portion  15 . The top board edge  4  of the corresponding sensor array  401  is recessed from the top rim  16  by an offset distance  402 , and the bottom board edge  5  is protruded from the bottom rim  17  by the offset distance  402 , which allows the plurality of segmented portions  15  to couple into each other. As can be seen in  FIG. 8 , the bottom board edge  5  of an arbitrary segmented portion  201  traverses through the top rim  16  of an adjacent segmented portion  202 , which allows the bottom board edge  5  of the arbitrary segmented portion  201  to be positioned against the top board edge  4  of the adjacent segmented portion  202 . In some versions of the segmented embodiment, each of the segmented portions  15  comprises a D-ring  501 , a D-groove  502 , locking clips  503 , and receiving sockets  504 . The D-ring  501  and the D-groove  502  are positioned opposite of each other on each segmented portion  15 , and the D-ring  501  of an arbitrary segmented portion  201  would engage the D-groove  502  of an adjacent segmented portion  202  in order to interlock the arbitrary segmented portion  201  and the adjacent segmented portion  202 . The locking clips  503  and the receiving sockets  504  are positioned opposite of each other on each segmented portion  15 , and the locking clips  503  of an arbitrary segmented portion  201  would engage the receiving sockets  504  of an adjacent segmented portion  202  in order to further interlock the arbitrary segmented portion  201  and the adjacent segmented portion  202 . 
         [0024]    The components of present invention can be made of any materials that are suitable towards their functionality. In the preferred embodiment, the components of the present invention are made of materials that improve their functionality. The lateral enclosure  1  can be made of plastic or non-magnetic metal depending on the application of the present invention. For more benign environments, polyvinyl chloride (PVC) can be used for the lateral enclosure  1 . For more aggressive environments, fluorinated ethylene propylene (FEP) can be used for the lateral enclosure  1 . The circuit board  3  is made of, but is not limited to, a FR-4 glass proxy or polyimide. The magnetic float  12  can comprise a dense plastic housing that positions magnets to properly trigger the plurality of Hall-Effect sensors  6 . 
         [0025]    The power sequence can be described as follows: On first power-up, the central controller  13  will query each of plurality of sensor arrays  2  to determine the location of the floats. Once the location of the floats is determined, the central controller  13  will power down (into low power sleep mode) all sensor arrays that did not detect the presence of the magnetic float  12 . The sensor array that did detect the magnetic float  12  will only power the active Hall-Effect sensors and one or two Hall-Effect sensors  6  above and below the active Hall-Effect sensor. The active sensors will then go to sleep, waiting for a change in float position. This power management algorithm provides highly efficient power control and minimizes power consumption for battery operated systems. 
         [0026]    Since this system is extremely flexible, it can remain powered up at all times if it is powered externally and power consumption is not a critical operating parameter. 
         [0027]    The power management algorithm can also work when the float is between two sensors. This function works as follows: If a float is between two Hall-Effect sensors  6 , both Hall-Effect sensors  6  will be active “on” and only these sensors will be powered. If the magnetic float  12  moves, then one Hall-Effect sensor will go “off”, which will wake up the system since a change has been detected. 
         [0028]    The present invention is designed to operate in conjunction with the central controller  13 . The microcontroller  7  on each sensor array  2  manages the power for that sensor array. If a change is detected on a particular sensor array, that sensor array will assert the notification signal to wake up the central controller  13 . The central controller  13  then queries the sensor arrays  2  to determine the new location of the magnetic float  12 . Once the new location has been determined, the present invention will go back to sleep until another change event occurs. 
         [0029]    Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.