Abstract:
A self-alignment filling level detecting device has a reflector and a sensor detachable from each other. The sensor has a light emitter, a light sensor, and a controller. The light sensor receives different light intensities when the reflector is assembled to the sensor and when the reflector is not assembled to the sensor. Thus, the controller determines whether the reflector has been accurately engaged and aligned with the sensor or not based on sensing results of the light sensor. Since the reflector and the sensor are detachable from each other, either the reflector or the sensor can be replaced individually if any one of them malfunctions.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a self-alignment filling level detecting device, and more particular to a self-alignment filling level detecting device comprised of a reflector and a sensor detachable from each other. 
         [0003]    2. Description of the Prior Art 
         [0004]    Optical level detecting devices are widely used in many different fields such as petrochemical industry, foodstuff industry, iron and steel industry, cement industry, etc. to measure a filling level of raw material or liquid stored in a container. 
         [0005]    With reference to  FIG. 18 , the U.S. Pat. No. 6,921,911, entitled “Method and device for optically determining a filling level in liquid-filled containers”, provides a detecting device  80  to be mounted on a wall  91  of a container. The detecting device  80  comprises a body  81  and a circuit board  82 . 
         [0006]    The body  81  has multiple stepped portions  811 , which are connected by reflection faces  812 ,  812 ′. The stepped portions  811  and reflection faces  812 , 812 ′ have different diameters, wherein the stepped portion  811  at top has a greater diameter than a diameter of the stepped portion at bottom. Each reflection face  812 ,  812 ′ corresponds to an individual liquid level. Further, the bottom-most reflection faces  812 ′ at a lower end of the body  81  form a V-shape in cross-section. 
         [0007]    The circuit board  82  has a light source  821  and a light sensor  822 . The light source  821  emits collimated light beams to the reflection faces  812 ,  812 ′. In this example, only the bottom-most reflection face  812 ′ is immersed in liquid  92  while other reflection faces  812  are exposed in air. Therefore light beams impinging on the reflection faces  812  in air experience total reflection and are reflected to the light sensor  822 . On the other hand, the light beam incident on the bottom-most reflection face  812 ′ is not reflected to the light sensor  822  but is refracted into the liquid  92 . Thus, the circuit board  82  can determine the liquid level in the container based on reflected light beams received by the light sensor  822 . 
         [0008]    To obtain a precise light reflection path, the body  81  and the circuit board  82  are integrally formed together to ensure that the light incident on the reflection faces  812  can be totally reflected. Thus, the body  81  and the circuit board  82  are mounted in the container at the same time. When either the body  81  or the circuit board  82  fails, the entire detecting device  80  should be replaced with a new one. 
         [0009]    If the body  81  and the circuit board  82  are separated from each other instead of integrally formed together, the accuracy of light reflection may be adversely affected because of the incorrect or improper alignment between the body  81  and the circuit board  82 , thus causing level detecting error. 
         [0010]    To overcome the shortcomings, the present invention provides a self-alignment filling level detecting device to mitigate or obviate the aforementioned problems. 
       SUMMARY OF THE INVENTION 
       [0011]    The main objective of the present invention is to provide a self-alignment filling level detecting device comprised of a reflector and a sensor detachable from each other. If the reflector or the sensor malfunctions, the failed one can be individually replaced. Further, when the reflector has been accurately engaged with the sensor, a circuit board provided in the sensor will recognize the assembly of the reflector and the sensor. 
         [0012]    According to one preferred embodiment, a light emitter, a light controller, and a light isolator are provided in the sensor of the self-alignment filling level detecting device. The light isolator is movably configured for isolating the light emitter from the light sensor, or providing an optical path to communicate the light emitter with the light, based on relative positions between the reflector and the sensor. 
         [0013]    Therefore, according to the light intensity received by the light sensor, the relative positions between the reflector and the sensor can be obtained. The controller thus determines whether the reflector is accurately assembled and aligned with the sensor and ensures high accuracy of filling level detection. When either the reflector or the sensor malfunctions, the failed one can be individually replaced with a new one without need of discarding the entire filling level detecting device. 
         [0014]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is an exploded perspective view of a self-alignment filling level detecting device of the present invention; 
           [0016]      FIG. 2  is a cross-sectional view showing a reflector not yet assembled to a sensor of the present invention; 
           [0017]      FIG. 3  is a cross-sectional view showing the reflector assembled to the sensor of the present invention; 
           [0018]      FIG. 4  is a cross-sectional view showing the self-alignment filling level detecting device of the present invention being mounted in a side wall of a container; 
           [0019]      FIG. 4A  a cross-sectional view showing the self-alignment filling level detecting device of the present invention is mounted in the side wall and the reflector is immersed in liquid; 
           [0020]      FIG. 5  is cross-sectional view showing an aperture formed in a linking tube of the present invention; 
           [0021]      FIG. 6  is a plan view of a light isolator of a second embodiment of a light isolator of the present invention; 
           [0022]      FIG. 7  is a perspective view showing the light isolator and a contact switch; 
           [0023]      FIG. 8  is a top plan view of the light isolator and the contact switch in  FIG. 7 ; 
           [0024]      FIG. 9  is a top plan view showing the light isolator electrically touching the contact switch; 
           [0025]      FIG. 10  is an exploded perspective view showing another embodiment of a reflector and a linking tube having a light gate of the present invention; 
           [0026]      FIG. 11  shows operations of the light gate in  FIG. 10 ; 
           [0027]      FIG. 12  is an exploded perspective view showing yet another embodiment of a reflector and a screwing sleeve of the present invention; 
           [0028]      FIG. 13  is a cross sectional view of the reflector and the screwing sleeve of  FIG. 12  assembled together: 
           [0029]      FIG. 14  is an exploded perspective view showing yet another embodiment of a reflector and a screwing sleeve of the present invention; 
           [0030]      FIG. 15  is a cross sectional view of the reflector and the screwing sleeve of  FIG. 12  assembled together; 
           [0031]      FIG. 16  is an exploded perspective view showing another embodiment of a reflector and a linking tube of the present invention; 
           [0032]      FIG. 17  is a cross sectional view of the reflector and the linking tube of  FIG. 16  assembled together; 
           [0033]      FIG. 18  shows a conventional filling level detector mounted in a container wall. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    With reference to  FIGS. 1 and 2 , a first embodiment of a self-alignment filling level detecting device comprises a reflector  10  and a sensor  20  detachably connected to the reflector  10 . 
         [0035]    The reflector  10  comprises a tubular body, a reflection head  11 , and a connecting portion  12 . The reflection head  11  is mounted on a first end of the tubular boy and is in a shape of a cone, wherein the reflection head  11  has a V-shaped cross section with two opposite reflection faces  111 . The connecting portion  12  is formed at a second end of the tubular body opposite to the reflection head  11 . In this embodiment, the connecting portion  11  has a threaded outer surface. 
         [0036]    The sensor  20  comprises a body  21 , a cover  22 , a linking tube  30 , a light isolator  33 , a screwing sleeve  34 , and a circuit board  40 . 
         [0037]    The body  21  is hollow and has a first end, a second end opposite to the first end, and an opening  211  formed at the first end, wherein the cover  22  is mounted at the opening  211  of the body. 
         [0038]    The linking tube  30  protrudes from the second end of the body  21 . A protrusion  301  axially extends from one end of the linking tube  30  toward the reflector  10 , wherein two sensor channels  32  and a slot  31  are defined in the protrusion  301  and communicate with the linking tube  30 . The slot  31  is formed between the two sensor channels  32  and has a rectangular cross section. Each sensor channel  32  has a circular cross section. Further, with reference to  FIG. 5 , an aperture  321  communicating between the slot  31  and the two sensor channels  32  is formed in the protrusion  301 . 
         [0039]    The screwing sleeve  34  is mounted around the linking tube  30  and has a threaded inner surface such that the screwing sleeve  34  is correspondingly assemble to the connecting portion  12 . 
         [0040]    The circuit board  40  is mounted in the body  21  and has a light emitter  41 , a light sensor  42 , and a controller  43 . The light emitter  41  and the light sensor  42  are electronically connected to the controller  43  and are respectively held in the two sensor channels  32 . 
         [0041]    The light isolator  33  is a partition plate in this embodiment and is mounted in the slot  31  and has a front end toward the reflector  10 , and a rear end opposite to the front end. The light isolator  33  has a through hole  331  formed through the light isolator and has two hooks  332  axially extending from the rear end of the light isolator  33 . A spring  35  is received in the slot  31  and presses against the read end of the light isolator  33 . With reference to  FIGS. 2 and 3 , as the screwing sleeve  34  rotates in different directions, the reflector  10  will move forward or backward. When the reflector  10  moves toward the sensor  20  and is completely screwed to the sensor  20 , the front end of the light isolator  33  abuts a rear side of the reflection head  11  and the spring  35  is compressed. 
         [0042]    The through hole  331  may be formed through the light isolator  33  proximal to either the front end or the rear end, as shown on  FIG. 6 , based on the sensing methods of the controller  43 . The two hooks  332  abut against an inner wall of the slot  31  and limit the position the light isolator  33  to prevent the light isolator  33  from ejecting from the slot  31 . The following descriptions disclose the embodiments that the through hole  331  is formed proximal to the front end and that the through hole  331  is formed proximal to the rear end of the light isolator  33 , and the corresponding sensing methods of the controller  43 . 
         [0043]    A. The Through Hole  331  is Formed Proximal to the Front End of the Light Isolator  33   
         [0044]    When the through hole  331  is formed proximal to the front end of the light isolator  33  and the reflector  10  is not yet completely screwed to the sensor  20  as shown in  FIG. 2 , the light emitter  41  is isolated from the light sensor  42  by the light isolator  33 . When the reflector  10  is completely screwed to the sensor  20  and pushes the light isolator  33  to a predetermined position, the through hole  331  aligns with the light emitter  41  and the light sensor  42 , and a part of a light beam emitted from the light emitter  41  can directly impinge on the light sensor  42  through the through hole  331  as shown in  FIG. 3 . 
         [0045]    With reference to  FIG. 4 , when the reflector  10  is fixed in a wall  51  of a container or a tank and is not immersed in liquid, the light beam output from the light emitter  41  is totally reflected by the reflection head  11  to the light sensor  42 . With reference to  FIG. 4A , on the other hand, when the reflector  10  is immersed in liquid  52 , the light beam incident on the reflection head  11  is not reflected to the light sensor  42  but is refracted into the liquid  52 . 
         [0046]    Therefore, based on the light intensity sensed by the light sensor  42 , the controller  43  recognizes whether the reflector  10  has been immersed in the liquid  52  and correctly assembled to the sensor  20 . 
         [0047]    B. The Through Hole  331  is Formed Proximal to the Rear End of the Light Isolator  33   
         [0048]    When the through hole  331  is formed proximal to the front end of the light isolator  33  and the reflector  10  is not yet completely screwed to the sensor  20 , the through hole  331  aligns with the light emitter  41  and the light sensor  42 , and a part of a light beam emitted from the light emitter  41  can directly impinge on the light sensor  42  through the through hole  331 . 
         [0049]    On the other hand, when the reflector  10  is completely screwed to the sensor  20  and pushes the light isolator  33  to a predetermined position, the light emitter  41  is isolated from the light sensor  42  by the light isolator  33 . The light sensor  42  only detects the refracted light from the reflection head  11  when the reflector  10  is immersed in the liquid. Thus, the controller  43  still can recognize whether the reflector  10  has been assembled to the sensor  20  correctly. 
         [0050]    With reference to  FIGS. 7 to 9 , the circuit board  40  may further comprise a contacting switch  44  comprised of two C-shaped conductive sheets  441 . The switch  44  is triggered to generate either a conduction signal (short circuit signal) or a non-conduction signal (open circuit signal) depending on the position of the light isolator  33 . Based on the signal of the contacting switch  44 , the controller  43  recognizes whether the reflector  10  has been accurately assembled to the sensor  20 . 
         [0051]    In one embodiment, the two conductive sheets  441  are configured back-to-back on the circuit board  40  and contact each other. When the light isolator  33  moves toward the circuit board  40  and the hook  332  separates the two conductive sheets  441  from each other, the contacting switch  44  changes its status and generates the non-conduction signal. The controller  43  recognizes that the reflector  10  has been accurately assembled to the sensor  20  based on the non-conduction signal. 
         [0052]    In another alternative embodiment, the two conductive sheets  33  are configured separately on the circuit board  40  and spaced apart from each other. The hook  332  of the light isolator  33  should be conductive or coated with a conductive layer. When the light isolator  33  moves toward the circuit board  40  and the hook  332  interferes between the two conductive sheets  441 , the hook  332  electronically contacts the two conductive sheets  441 . The contacting switch  44  changes its status and generates the conduction signal. The controller  43  recognizes that the reflector  10  has been accurately assembled to the sensor  20  based on the conduction signal. 
         [0053]    With reference to  FIGS. 10 and 11 , the light isolator  33   b  is a light gate with an adjustable light aperture. The light gate is configured in front of the light emitter  41  and the light sensor  42  and is comprised of multiple gate plates  333 . As the screwing sleeve  34  rotates to assemble the sensor  20  to the reflector  10 , all the gate plates  333  are also driven to adjust the size of the light aperture. For example, when the reflector  10  has been assembled to the sensor  20 , the light gate is completely open and the light beam emitted from the light emitter  41  can pass through the light gate and eventually reflected by the reflection head  11  to the light sensor  42 . Therefore, the controller  43  can recognize that the reflector  10  has been accurately assembled to the sensor  20 . On the other hand, if the reflector  10  is not yet assembled to the sensor  20  at the predetermined position, the light gate is closed. The light beam emitted from the light emitter will be blocked by the light gate and not reflected. 
         [0054]    With reference to  FIGS. 12 and 13 , multiple spiral grooves  121 , instead of threads, are formed on the outer surface of the connecting portion  12 . A rib  122  and a recess  123  are formed at a distal end of each spiral groove  121 . Multiple positioning blocks  341 , instead of inner threads, are formed on the inner surface of the screwing sleeve  34 . The positioning blocks  341  move along the spiral grooves  121  and eventually engaged in the recesses  123  as the screwing sleeve  34  rotates to fasten the reflector  10  to the sensor  20 . 
         [0055]    With reference to  FIGS. 14 and 15 , this embodiment is similar to the embodiment of  FIGS. 12 and 13 . The difference is that two ribs  122 ,  122 ′ and a recess  123  between the two ribs  122 , 122 ′ are formed in the distal end of each spiral groove  121 . Multiple positioning blocks  341  are formed on the inner surface of the screwing sleeve  34 . The positioning blocks  341 ′ move along the spiral grooves  121  and eventually engage in the recesses  123  as the screwing sleeve  34  rotates to fasten the reflector  10  to the sensor  20 . 
         [0056]    With reference to  FIGS. 16 and 17 , multiple positioning recesses  124  are formed in the inner surface of the connecting portion  12 . Multiple blocks  37  are formed on the outer surface of the linking tube  30  to be correspondingly engaged in the positioning recesses  124 , wherein each block  37  has an inclined top surface. 
         [0057]    In the present invention, the light isolator  33  can separate the light emitter  41  from the light sensor  42  or provide a light path communicating between the light emitter  41  and the light sensor  42 . The controller  43  determines whether the reflector  10  has been correctly assembled to the sensor  20  based on the light status between the light emitter  41  and the light sensor  42 . The reflector  10  can engage with the sensor  20  via the matched threads formed on the connecting portion  12  and the screwing sleeve  34 , or via the recesses  124  and the blocks  37 . 
         [0058]    For repair or maintenance purposes, either the reflector  10  or the sensor  20  can be individually replaced with a new one. After the replacement, both the reflector  10  and the sensor  20  still maintain correct alignment between each other to ensure high accuracy of filling level detection. 
         [0059]    Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.