Patent Abstract:
A leakage inspecting device for a sealing stopper in a mouth portion of a container, including a positioning member including an inner stand wall, the inner stand wall having a diameter larger than a boundary surface between the mouth portion and a brush attached to the mouth portion and configured to make watertight contact with the mouth portion, a first placing unit configured to place the positioning member on the mouth portion at an inspection spot and align axis centers of the positioning member and mouth portion, a second placing unit configured to place the inner stand wall onto an upper surface of the mouth portion and situate the inner stand wall on the mouth portion, an injection unit configured to inject water into the inner stand wall and mouth portion, and a measuring unit including a probe configured to measure electric conductivity of the water.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to a liquid leakage inspecting device which inspects a barrel-like liquid container containing beer, for instance, and detects liquid leakage from the mouth of the container. 
     BACKGROUND OF THE INVENTION 
     Conventionally, a container for beer is barrel-shaped and made of an aluminum plate or steel plate. The barrel-shaped container is strong, and has a relatively large capacity. The capacity of such a container is 7 litters, 10 litters, 15 litters, 20 litters, 25 litters, or 50 litters. The container is provided with a sealing stopper unit in its mouth portion to maintain the quality of the content liquid sealed in the container, and to prevent the content liquid from deteriorating and losing flavor. 
     The sealing stopper unit comprises: a mouth portion  1   a  formed on the upper surface or the lower surface of a container  1  containing liquid such as beer B; a bush a placed in the mouth portion  1   a;  a liquid raising cylindrical member c inserted into the bush a by the pushing force of first springs b; a gas valve d provided on the outer periphery of the upper surface of the liquid raising cylindrical member c so as to be engaged with the inner surface of the upper portion of the bush a; and a solution valve f which raises the content liquid by pressure air G supplied into the container  1  through the liquid raising cylindrical member c when the gas valve d is opened by the pushing force of second springs e, and which valve f discharges the content liquid out of the container  1 . 
     In the production line of the beer B, defective products whose content liquid is leaking from the mouth portion  1   a  of the container  1  are detected and then discharged out of the main line of the production line. The container  1  is repeatedly used in view of resource conservation. 
     In the liquid leakage inspecting device, which judges whether the content liquid is leaking from the mouth portion  1   a  of the container  1 , pure water w is injected into a concave portion g formed on the upper surface of the sealing stopper unit  4 ′ in the mouth portion  1   a  of the container  1 , and a probe P is then put in the pure water w to measure its electric conductivity, thereby detecting liquid leakage. 
     In FIGS. 8 and 9, cylinders S′ 1  are disposed on both sides of a conveyer  2 ′ which transports the container  1  having the sealing stopper unit  4 ′ in the mouth portion  1   a.  The rods of the cylinders S′ 1  are provided with clamp units  12 ′ which can be opened and closed with respect to rotational axes  16 ′. The clamp units  12 ′ are connected to holding frames  15 ′ provided with rollers  14 ′, and holds the container  1  for liquid leakage inspection by a leakage inspecting unit  20 ′. In the next step to the clamp units  12 ′ on the conveyer  2 ′, cylinders S′ 2  provided on both sides of the conveyer  2 ′ are actuated to extend the rods toward the axis center O of the container  1 . Stopper units  17 ′ having contact portions are attached to the edges of the respective rods of the cylinders S′ 2 . In the next step to the stopper units  17 ′, a water supply unit  31 ′ which supplies the pure water w into the concave portion g formed in the upper portion of the sealing stopper unit  4 ′ is formed. In the next step to the water supply unit  31 ′, a probe P and a leakage inspecting unit  20 ′ are formed. The double-cylindrical probe P is inserted into the pure water w supplied into the concave portion g to measure the electric conductivity of the water, thereby judging whether the content liquid is leaking from the mouth portion  1   a.  The leakage inspecting unit  20 ′ is provided with a water supply unit  31 ″ which rotates in the vertical direction by 90 degrees in the ascending position of the probe P after the measurement, and which water supply unit  31 ″ supplies wash water to wash the probe P. In the next step to the leakage inspecting unit  20 ′, an air supply unit  43 ′ which blows dry air or hot air to the water in the concave portion g is provided. In the next step to the air supply unit  43 ′, a reject conveyer  45 ′ is provided. The reject conveyer  43 ′ transports the container  1  judged to be a defective product having leakage and discharged out of the main line of the production line by actuating a reject cylinder S′ 6 . 
     Positioning units  21 ′ are formed in the locations of the water supply unit  31 ′, the leakage inspecting unit  20 ′, and the air supply unit  43 ′. Each of the positioning units  21 ′ stops and positions the container  1  being transported on the conveyer  2 ′. Cylinders S′ 3  and S′ 4  as driving power sources are provided on both sides of the conveyer  2 ′. The edge of each rod of the cylinders S′ 3  is provided with a grip unit  50 ′ having an arcuate inner surface  50 ′ a  corresponding to the outer peripheral surface  1   b  of the container  1 . Each rod of the cylinders S′ 4  extends toward the axis center O of the container  1 , and is provided with a contact portion  24 ′ (not shown) which can be in contact with the outer peripheral surface  1   b  of the container  1 . The conveyer  2 ′ is a belt conveyer or a roller conveyer, for instance. 
     In a conventional liquid leakage inspecting unit shown in FIG. 8, pure water is injected into the concave portion g formed in the mouth portion g of the container  1  being transported on the conveyer in the pure water injecting position. When the container  1  being transported on the conveyer reaches the inspecting position, the probe P is inserted into the pure water in the concave portion g to measure the electric conductivity of the water. Here, the pure water injecting position is situated at a distance from the inspecting position. Because of this, the pure water injected into the concave portion g of the container in the pure water injection position is subjected to the vibration from the conveyer or the shock caused by the container  1  brought into contact with the guide members. As a result, the pure water flows out of the concave portion, hindering accurate measure of the electric conductivity. 
     There is another problem that the electric conductivity can be measured only when the beer B is leaking into the pure water from the gas valve d or the solution valve f of the sealing stopper unit  4 ′, because the probe P is inserted into the pure water w injected only into the concave portion g formed on the upper surface of the sealing stopper unit  4 ′. 
     In other words, leakage from the boundary between the mouth portion  1   a  and the bush a cannot be detected. 
     In the conventional liquid leakage inspecting device shown in FIGS. 8 and 9, the probe P is rotated in the vertical direction by 90 degrees in its ascending position after the leakage detection by the probe P inserted into the pure water w supplied into the concave portion g of the mouth portion  1   a  from the water supply unit  31 ′ of the leakage inspecting unit  20 ′. The water supply unit  31 ″ then supplies wash water to wash the probe P. After that, the air supply unit  43 ′ provided in the next step to the leakage inspecting unit  20 ′ blows dry air or hot air to dry the washed probe P. 
     As described above, washing the probe P requires a rotating operation of the probe P. Also, since the air supply position is situated at a distance from the water supply position, the drying of the probe P adds to the number of procedures, resulting in poor efficiency of the liquid leakage inspection on the conveyer  2 ′. 
     Furthermore, since the water supply unit  31 ″ supplies water only to the outer surface of the probe P, the inside of the double-cylindrical probe P cannot be sufficiently washed. As a result, dust and impurities remain in the probe P, thereby causing a problem that accurate leakage detection cannot be achieved with the repeatedly used probe P. 
     In the conventional liquid leakage inspecting device shown in FIG. 8, the container  1  being transported on the conveyer  2 ′ is sandwiched by the rollers  14 ′ in the clamp unit  12 ′ when the cylinders S′ 1  as the driving power sources on both sides of the conveyer  2 ′ are actuated. In the stopper unit  17 ′, the contact portions  24 ′ at the edges of the extended rods of the cylinders S′ 2  disposed on both sides of the conveyer  2 ′ are brought into contact with the sides and the front of the outer peripheral surface  1   b,  thereby stopping the transportation of the container  1 . In the locations of the water supply unit  31 ′, the leakage inspecting unit  20 ′, and the air supply unit  43 ′, each of the cylinders S′ 3  and S′ 4  disposed on both sides of the conveyer  2 ′ is actuated so that the container  1  is sandwiched by the contact portion  24 ′ and the corresponding grip unit  50 ′ having the arcuate inner surface  50 ′ a.    
     The barrel-shaped container  1  made of an aluminum plate or a steel plate is forcibly pressed at both sides by the cylinders S′ 1  to S′ 4  disposed on both sides of the conveyer  2 ′, every time axis center matching, positioning, or transportation halting is performed on the conveyer  2 ′. As a result, the outer surface of the container  1  is often damaged or deformed. If repeatedly used over a long period of time, the container  1  is deformed during transportation or storing, resulting in irregularity in shape. 
     If the container  1  is deformed, the nozzle of the water supply unit  31 ′ is situated outside the concave portion g. In such a case, the pure water necessary for the inspection cannot be pooled sufficiently in the concave portion g. Also, the axis center O′ of the probe P does not correspond to the axis center O of the container  1  and is situated outside the concave portion g. As a result, the probe P cannot be inserted properly into the concave portion g, but the probe P might be brought into contact with the inner surface of the concave portion g instead. This causes errors in the leakage inspection, and containers might be wrongly judged to be defective products even when there is no leakage. With the above problems, accurate leakage detection cannot be expected. 
     If the containers vary in size, it is necessary to change the grip units  50 ′ in accordance with the size of each container. 
     The present invention provides a liquid leakage inspecting device which eliminates the above problems with the conventional liquid leakage inspecting device, such as the poor accuracy in the detection due to the insufficient amount of pure water, and the inability to detect leakage from the boundary between the mouth portion of the container and the bush. In the liquid leakage inspecting device of the present invention, the pure water injecting position corresponds to the inspecting position on the conveyer, and the pure water necessary for the inspection is supplied in the inspecting position. The pure water is prevented from flowing out during the transportation of the container, so that the electric conductivity can be measured with high accuracy. Accordingly, the liquid leakage inspection can be efficiently conducted. Also, liquid leakage from the boundary between the inner surface of the mouth portion of the container and the outer surface of the bush can be automatically and quickly detected. Moreover, the structure of the device of the present invention is simple, and the number of components is small. Thus, compared with the prior art, the production procedures can be simplified, and the production costs can be reduced. 
     The present invention also provides a liquid leakage inspecting device which eliminates the problem with the drying and washing of the conventional probe, performs the washing and drying of the probe in a short time with little trouble, and efficiently conducts liquid leakage inspection with high accuracy. 
     The present invention further provides a liquid leakage inspecting device which eliminates the problems with the prior art, such as the inaccurate inspection due to damage or deformation of the container, and inability to comply with different sizes of the container. In the liquid leakage inspecting device of the present invention, the container being transported on the conveyer can be prevented from being damaged or deformed, so that the container can be repeatedly used over a long period of time. The axis matching of the probe can be easily and accurately in accordance with the shape and size of the container, and the container can be easily and accurately positioned and stopped at a desired inspecting spot. The pure water for the leakage inspection can be sufficiently supplied into the concave portion, and the container can be prevented from being wrongly judged to be a defective product. Thus, the device of the present invention can perform highly accurate liquid leakage inspection. 
     SUMMARY OF THE INVENTION 
     To eliminate the above problems, the present invention provides a leakage inspecting device which has a sealing stopper unit comprising: a bush attached to a mouth portion of a container containing liquid such as beer being transported on a conveyer; a liquid raising cylindrical member movably inserted into the bush in the vertical direction; a gas valve which can be opened and closed, is formed on the outer periphery of the upper surface of the liquid raising cylindrical member, and is engageable with the inner surface of the upper portion of the bush; and a solution valve which raises the content liquid through the liquid raising cylindrical member by supplying pressure air into the container when the gas valve is opened, and then discharges the content liquid out of the container, and which device measures the electric conductivity of water by inserting a probe into pure water supplied into a concave portion formed in the upper portion of the sealing stopper unit in the mouth portion of the container, thereby judging whether the content liquid is leaking. The leakage inspecting device comprises: a unit which places a positioning member on the mouth portion of the container being transported on the conveyer at an inspecting spot, with the axis center of the positioning member corresponding to the axis center of the mouth portion of the container; a unit which places an inner stand wall onto the upper surface of the mouth portion and also situates the inner stand wall on the outer periphery of the mouth portion, the inner stand wall being formed inside the positioning unit and having a larger diameter than a boundary surface between the mouth portion of the container and the bush attached to the mouth portion; a unit which inject the pure water into the inner stand wall and the concave portion formed in the mouth portion connected to the inner stand wall; and a unit which measures the electric conductivity of the water by inserting the probe into the pure water injected into the inner stand wall and the concave portion of the mouth portion, thereby judging whether the content liquid is leaking from the container. 
     In the leakage inspecting device of the present invention, the positioning unit can move up and down, and can cover the mouth portion of the container being transported on the conveyer. Also, an inclined guide portion which can forcibly move the container in the direction of the axis center thereof by touching the mouth portion is formed on the inner surface of the lower portion of the positioning unit. 
     The container and the probe can be moved up and down relatively with each other by driving power sources, and the probe is inserted into the mouth portion of the container. 
     The positioning unit is secured below an attachment plate in such a manner that the positioning unit can be placed onto the mouth portion, and the probe having a protruding edge is attached to the attachment plate. 
     The positioning unit may be disposed separately from an attachment plate in such a manner that the positioning unit can be placed onto the mouth portion, and the probe having a protruding edge is attached to the attachment plate. 
     The positioning unit is externally shaped like an up-side-down saucer or a bell, and a step portion which can be placed on the upper rim of the mouth portion of the container is formed on the lower surface of the inner stand wall. The step portion intersects the axis center. An inclined guide portion which broadens downward is formed under the step portion. The inclined guide portion matches the axis centers with each other by forcibly moving the mouth portion of the container in a horizontal direction intersecting the axis center when the positioning unit covers the mouth portion. 
     The leakage inspecting device of the present invention further comprises a water supply unit which supplies wash water to the probe and an air supply unit which blows dry air or hot air to the probe. The water supply unit and the air supply unit are situated in the ascending position of the probe in the inspecting position. 
     The probe has a water passing hole which communicates with the water supply unit and an air injection hole which communicates with the water supply unit. The water passing hole and the air injection hole are situated on the outer periphery of the probe. 
     In the leakage inspecting device of the present invention, a movable guide bar which adjusts the transportation width of the conveyer in accordance with the size of the container being transported is attached to one side of the conveyer. The axis center of the probe of the leakage inspecting unit corresponds to the center line extending in the longitudinal direction of the transportation width. 
     The conveyer is provided with a stopper unit comprising a guide bar movable in a direction intersecting a transportation direction of the container by a driving force of a cylinder as a driving power source on one side of the conveyer, and a rod which can be moved toward the axis center of the container by a driving force of another cylinder, and can be in contact with an outer peripheral surface of the container, and extension lengths of rods of the two cylinders are controlled in accordance with the size of the container being transported, so that the axis center of the probe is matched with the center line of the transportation width of the conveyer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is a plan view of a first embodiment of a liquid leakage inspecting device of the present invention; 
     FIG. 2 is an enlarged sectional view taken along the line U—U of FIG. 1; 
     FIG. 3 is an enlarged sectional view illustrating a liquid leakage inspection performed by a leakage inspecting unit of the first embodiment; 
     FIG. 4 is an enlarged sectional view of a conveyer of the first embodiment; 
     FIG. 5 is an enlarged sectional view of a container having a sealing stopper unit in the mouth portion of the first embodiment; 
     FIG. 6 is an enlarged sectional view of a second embodiment of the present invention; 
     FIG. 7 is an enlarged sectional view of a conventional beer container having a sealing stopper unit in the mouth portion; 
     FIG. 8 is a plan view of one example of a conventional liquid leakage inspecting device; and 
     FIG. 9 is an enlarged front view of a probe and a feed unit in the leakage inspecting unit of the conventional liquid leakage inspecting device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a description of embodiments of the present invention, with reference to the accompanying drawings. 
     FIGS. 1 to  5  illustrates the first embodiment of the present invention. In these figures, reference numeral  1  indicates a container to be transported on a production line, i.e., a barreling line  3 , by a conveyer  2 . The container  1  is barrel-shaped and made of an aluminum plate or steel plate. A mouth portion  1   a  is formed on the upper surface of the container  1 . The container  1  can vary in size and capacity, such as 7 litters, 10 litters, 15 litters, 20 litters, 25 litters, or 50 litters. 
     A sealing stopper unit  4  which is substantially the same as the conventional sealing stopper unit is disposed in the mouth portion  1   a  of the container  1 . A concave portion  5  is formed on the upper portion of the sealing stopper unit  4 . 
     The sealing stopper unit  4  comprises a bush  6 , a liquid raising cylindrical member  7 , a gas valve  9 , and a solution valve  11 . The bush  6  is disposed in the mouth portion  1   a  of the container  1 . The liquid raising cylindrical member  7  is inserted into the bush  6  by the pushing force of first springs  8  so that one end  7   a  of the liquid raising cylindrical member  7  extends deep into the container  1 . A gas valve  9  is disposed on the outer periphery of the upper surface of the liquid raising cylindrical member  7 , and is rotatably attached to the inner surface of the bush  6 . The solution valve  11  is disposed in the upper portion inside the liquid raising cylindrical member  7  by the pushing force of second springs  10 . The solution valve  11  can be opened and closed. When the gas valve  9  is opened, a pressure gas G such as carbon dioxide gas or compressed air is supplied into the container  1 , and beer B as the content liquid is raised by the welding pressure through the liquid raising cylindrical member  7 . The solution valve  11  then discharges the content liquid from the container  1 . 
     In FIG. 1, the conveyer  2  for transporting the container  1  is a roller conveyer or a belt conveyer as in the prior art. 
     However, the conveyer  2  is provided with clamp units  12  for positioning the axis center O with respect to the center line I in the longitudinal direction of the transportation passage of the conveyer  2 . The clamp units  12  hold the container  1  being transported on the conveyer  2  before the container  1  reaches an inspection site K where leakage of the content liquid is detected. In the next step on the conveyer  2 , a secondary water filling unit  13  is provided. The secondary water filling unit  13  stops the container  1  being transported on the conveyer  2 , and injects pure water w into the concave portion  5  of the mouth portion  1   a  of the container  1  so as to measure electric conductivity of water. 
     Although not shown in the figures, it is possible to employ a mouth portion washing unit which washes the mouth portion  1   a  of the container  1  being transported on the conveyer  2  by supplying pure water to the mouth portion  1   a,  and a drying unit which removes the pure water from the concave portion  5  of the mouth portion  1   a  of the container by blowing dry air into the concave portion  5  through an air supply nozzle. 
     The clamp units  12  rotatably support the base portions of a pair of holding frames  15  having rollers  14  at both sides of the conveyer  2  with rotational axes  16 . The rods of cylinders S 1  as driving power sources are connected to the holding frames  15 . The holding frames  15  are provided with the rollers  14 . When a sensor c 1  detects the container  1  being transported on the conveyer  2 , the cylinders S 1  are actuated to rotate the holding frames  15  about the rotational axes  16 . The outer peripheral surface  1   b  of the container  1  is then held by the rollers  14  so that the container  1  being transported on the conveyer  2  can be stopped for a leakage inspection. A sensor c 2  determines, before the cylinders S 1  are actuated, whether the axis center O of the container  1  sandwiched by the rollers  14  of the clamp units  12  is matched with the center line I. 
     Stopper units  17  are disposed on both sides of the conveyer  2  and the secondary water filling unit  13  at a predetermined angle θ with respect to the axis center O of the container  1 . The stopper units  17  are formed by contact portions  18  at the edges of the respective rods of cylinders S 2  as the driving power sources. The contact portions  18  can be brought into contact with the outer peripheral surface  1   b  of the container  1 . When a sensor c 3  detects the container  1  transported to the secondary water filling unit  13 , the cylinders S 2  are actuated to extend the rods, so that the contact portions  18  are brought into contact with the container  1  to stop the container  1  in a predetermined position on the conveyer  2 . 
     The conveyer  2  of this embodiment is provided with a movable guide bar  19  which can be moved in a direction perpendicular to the transportation direction of the container  1  by the driving force of the cylinder S 3  in accordance with the size of the container  1 . The guide bar  19  extends along the conveyer  2 , and the outer peripheral surface  1   b  of the container  1  is brought into contact with the guide bar  19 . On the opposite side to the guide bar  19 , a fixed guide bar  19 ′ is disposed along the conveyer  2 . 
     On the fixed guide bar  19 ′ side of the conveyer  2 , stopper units  21  which stop the container  1  on the conveyer  2  in accordance with its size are provided. The number of the stopper units  21  is the same as the number of leakage inspection units  20  formed at inspection points K 1 , K 2 , K 3 , and K 4  in the inspection site K. 
     The movable guide bar  19  is disposed along one side of the conveyer  2 , as shown in FIGS.  1  and  4 . The movable guide bar  19  is attached to splice plates  23  each formed at the edge of the rod of the corresponding cylinder S 3  attached to a sectionally L-shaped stationary plate  22 . The cylinder S 3  is then actuated, and its rod is extended in accordance with the size of the container  1  being transported by the cylinder S 3 , so that the transportation width L of the conveyer  2  can be adjusted with the contact portions  24  of cylinders S 4 . Also, the axis center O′ of the probe  27  of each leakage inspecting unit  20  is matched with the center line I of the transportation width L. 
     Each of the stopper units  21  is made up of a cylinder S 4  as a driving power source actuated by a sensor c 4  which detects the container  1  transported to the predetermined position, and a contact portion  24  which can be brought into contact with the outer peripheral surface  1   b  of the container  1 . The contact portion  24  is formed at the edge of the rod of the cylinder S 4 , which is movable toward the axis center O of the container  1  by the driving force of the cylinder S 4 . 
     In the secondary water filling unit  13 , the pure water w is supplied into the concave portion  5  through a pure water supply nozzle  25  prior to the liquid leakage inspection. The concave portion  5  is formed in the upper portion of the sealing stopper unit  4  in the mouth portion  1   a  of the container  1  being transported on the conveyer  2 . 
     The leakage inspecting units  20  are arranged in the transportation direction A of the container  1 , and the number of the leakage inspecting units  20  is the same as the number of the inspecting spots. In FIG. 4, the four leakage inspecting units  20 , for instance, are disposed to the four inspecting spots K 1 , K 2 , K 3 , and K 4 . Each of the leakage inspecting units  20  is detachably disposed on the upper surface of the mouth portion  1   a  of the container  1  being transported on the conveyer  2  right under the corresponding leakage inspecting unit  20  in the inspecting site K. Here, the axis center O′ of the probe  27  corresponds to the axis center O of the mouth portion  1   a  of the container  1 , and a positioning member  28  which can move up and down is provided so that the probe  27  can be inserted into the mouth portion  1   a.    
     The positioning unit  28  is made of plastic, hard rubber, and metal. As shown in FIGS. 2 and 3, the positioning unit  28  externally has the shape of an up-side-down saucer or a bell. The positioning unit  28  includes an inner stand wall  28   a,  a step portion  28   b,  and an inclined guide portion  28   c.  The inside of the positioning unit  28  broadens toward the bottom. The inner stand wall  28   a  has a larger diameter than the boundary surface T between the inner surface of the mouth portion  1   a  and the outer peripheral surface of the bush  6  disposed in the mouth portion  1   a  of the container  1 . The step portion  28   b  is formed on the lower surface of the inner stand wall  28   a,  and can be placed on the upper surface of the mouth portion  1   a  of the container  1  in a horizontal direction Y intersecting the axis center O′ of the probe  27 . The inclined guide portion  28   c  matches the axis center O′ of the probe  27  with the axis center O of the container by forcibly moving the container  1  in the horizontal direction Y intersecting the axis center O when the inclined guide portion  28   c  covers the mouth portion  1   a  of the container  1  via the step portion  28   b.    
     In this embodiment, the positioning unit  28  is incorporated into an outer casing  29  having an inclined guide portion  29   a  extending from the inclined guide portion  28   c  of the positioning unit  28 . The outer casing  29  protects and reinforces the positioning unit  28 . The outer casing  29  also facilitates and ensures the matching of the axis center O′ of the probe  27  with the axis center O of the container  1  by making the inclined guide portion  28   c  long enough to keep a large contact portion for the mouth portion  1   a  of the container. 
     The positioning unit  28  is fixed to the lower portion of an attachment plate  39  by a plurality of attachment bolts  30 . The leading edge  27   a  of the probe  27  protrudes from the attachment plate  39 . 
     The probe  27  has a water passing hole  27   b  facing a water supply unit  31  on one side of the outer peripheral surface, and an air injection hole  27   c  facing an air supply unit on the other side of the outer peripheral surface. The probe  27  is a double cylindrical electrode consisting of an outer cylindrical portion  27 A extending from the leading edge to the mid section, and a pillar  27 B situated inside the outer cylindrical portion  27 A. 
     The outer peripheral surface of the probe  27  is washed with the pure water w jetted from the water supply unit  31 . Furthermore, part of the pure water w is introduced forcibly into the probe  27  through the water passing hole  27   b  so as to completely wash away dust, impurities, and inspection water remaining in the probe  27 , by virtue of the surface tension during an inspection. In other words, every time the probe  27  is inspected for liquid leakage, the inside and outside of the probe  27  are cleaned. Thus, each inspection can be performed with high precision. 
     A driving unit  32  for moving the probe  27  up and down comprises: a cylinder S 5  which serves as a driving power source attached to a frame base  33 ; a stopper plate  35  secured by the rod  34  of the cylinder S 5 ; an attachment unit made up of a plurality of guide bolts  36  and nuts  37 ; and the attachment plate  30  elastically held by springs  38  wound around the guide bolts  36  with a distance H being kept from the stopper plate  35 . When the cylinder S 5  as the driving power source is actuated, the rod  34  is shortened and extended to move up and down the stopper plate  35  attached to the rod  34 , the attachment plate  39  held and secured to the stopper plate by the guide bolts  36  and the nuts  37 , and the positioning unit  28  attached to the attachment plate  39  by the attachment bolts  30 . 
     A sensor c 5  detects the descending position of the probe  27 , and actuates the cylinder S 5  to raise the rod. The descending position of the sensor c 5  depends on the size of the container  1  to be inspected. 
     A sensor c 6  detects the ascending position of the probe  27 , and then actuates the cylinder S 5  to lower the rod. 
     A water supply nozzle  41  supplies water into the concave portion  5  of the container  1  and the inner stand wall  28   a  of the positioning unit  28  disposed on the mouth portion  1   a  of the container  1 . The water supply nozzle  41  is included in the water supply unit  31  for washing the probe  27  after checking whether there is leakage of the content liquid. The water supply nozzle  41  is connected to a water supply pipe  42  penetrating through the attachment plate  39 , and the edge of the water supply nozzle  41  faces toward the water passing hole  27   b  formed in the outer periphery of the mid section of the probe  27 . The water supply nozzle  41  jets the pure water w as wash water, so that the inside and outside of the probe  27  are cleaned after each liquid leakage inspection by the probe  27 . Thus, the probe  27  can always be prepared for the next inspection. 
     An air blow nozzle  43  dries the probe  27  washed by the water jetting from the water supply nozzle  41  of the water supply unit  31 . The air blow nozzle  43  is connected to an air supply pipe  44  penetrating through the attachment plate  39 , and the edge of the air blow nozzle  43  faces toward the air injection hole  27   c  formed in the outer periphery of the mid section of the probe  27 . Every time the probe  27  is washed by the water supplied from the water supply nozzle  41 , the air blow nozzle  43  supplies dry air or hot air to dry the inside and outside of the probe  27 . 
     A cylinder S 6  is a rejecting cylinder for discharging the container  1  onto a reject conveyer  45  when the leakage detecting units  20  detect leakage from the container  1 . The rejecting cylinder S 6  is disposed in a direction intersecting the transportation direction A of the conveyer  2 , and is actuated when a sensor c 7  detects the container  1  being transported. 
     The first embodiment of the leakage inspecting device of the present invention has the structure as described above. The following is a description of a liquid leakage inspection method and its effects. 
     First, the beer B as the content liquid is sealed into the container  1  on the production line, or the barreling line  3 , and the container  1  is then transported in an erect state on the conveyer  2 . 
     When the censor c 1  detects the container  1  being slowly transported on the conveyer  2 , the cylinders S 1  as the driving power source of the clamp units  12  disposed on both sides of the conveyer  2  are actuated to extend the rod. Here, the holding frames  15  connected to the rod are rotated about the rotational axes  16 . The container  1  is held by the rollers  14  attached to the holding frames  15  so as to avoid congestion during the transportation. 
     The conveyer  2  may be stopped at the same time that the clamp units  12  hold the container  1 , but the conveyer  2  may also be kept in operation for higher efficiency of inspection and transportation of the container  1 . If a belt conveyer is used as the conveyer  2 , the container  1  should be transported slowly enough to restrict the friction between the bottom of the container  1  and the belt conveyer, so that the clamp units  12  can match the axis center O of the container  1  with the center line I of the conveyer  2 . Here, the extension of the rods of the cylinders S 1  are controlled based on the size of the container  1 , so that the axis center O of the container  1  can be matched with the center line I of the conveyer  2 . Also, the axis center O′ of the probe  27  of the leakage inspecting units  20  used for inspection corresponds to the center line I of the conveyer  2 . 
     If a roller conveyer is used as the conveyer  2 , the roller around the rotational axis should rotate by virtue of the rotational force of the rotational axis. When the clamp units  2  hold the container  1 , the rotational axis of the roller conveyer of the above type spins without engaging the roller. In such a case, it is not necessary to stop the conveyer  2  to efficiently stop the container  1  on the conveyer  2  or resume the transportation of the container  1 . 
     When the clamp units  12  hold the container  1  and the sensor c 2  detects a stop of the transportation of the container  1  on the conveyer  2 , the cylinders S 1  as the driving power sources are restarted to shorten the rods of the cylinders S 1 , and the holding frames  15  are rotated with the rollers  14  about the rotational axes  16 . Thus, the holding frames  15  are opened, and the container  1  is transported to the next stage by the conveyer  2 . 
     When the sensor c 3  detects the container  1  transported to the secondary water filling unit  13  by the conveyer  2 , the cylinders S 2  as the driving power sources for the stopper units  17  are actuated to extend the rods, and the container  1  being transported on the conveyer  2  is brought into contact with the contact portions  18  formed at the edges of the respective rods, thereby stopping the transportation of the container  1 . 
     When the container  1  is stopped, the pure water supply nozzle  25  supplies the pure water w into the concave portion  5  formed in the upper portion of the sealing stopper unit  4  in the mouth portion  1   a  of the container  1 . Since the extension of the rods of the cylinders S 2  is controlled so that the axis center O of the container  1  corresponds to the center line I of the conveyer  2 , the concave portion  5  can be surely filled with the pure water w. 
     The container  1  having the pure water w in the concave portion  5  is then transported to empty leakage inspecting units  20  among the four leakage inspecting units  20  of this embodiment formed on the conveyer  2  adjacent to the secondary water filling unit  13 . 
     When the sensor c 4  detects the container  1  transported to one of the leakage inspecting units  20  at the inspection points K 1 , K 2 , K 3 , and K 4 , the cylinder S 4  of the stopper unit  21  disposed on one side of the conveyer  2  is actuated to extend its rod toward the axis center O of the container  1 . Here, the contact portion  24  formed at the edge of the rod is brought into contact with one side of the outer peripheral surface  1   b  of the container  1 , and the guide bar  19  disposed on the other side of the conveyer  2  is brought into contact with the other side of the outer peripheral surface  1   b  of the container  1 . Thus, the contact portion  24  and the guide bar  19  softly hold the container  1  at one of the inspection points K 1 , K 2 , K 3 , and K 4 . 
     Since the guide bar  19  is attached to the splice plates  23  provided to the edges of the respective rods of the cylinders S 3  attached to the sectionally L-shaped fixed plates  22 , the cylinders S 3  are actuated to extend the rods in accordance with the size of the container  1 , thereby adjusting the transportation width L of the conveyer  2 . Also, the container  1  is free of unnecessary pressure, because the container  1  is stopped on the conveyer  2 , with one side of the outer peripheral surface  1   b  being in contact with the guide bar  19 , and the other side of the outer peripheral surface  1   b  being in contact with the contact portion  24  on the extended rod of the stopper unit  21 . Here, the outer peripheral surface  1   b  of the container  1  can be prevented from being deformed or damaged, so that the container  1  can be repeatedly used. Also, the container  1  is stopped at a point where the axis center O of the container  1  is matched with the center line I. Thus, the positioning and transportation of the container  1  can be surely carried out. 
     When the sensor c 4  detects the container  1  being transported directly under one of the leakage inspecting units  20  at the inspection points K 1 , K 2 , K 3 , and K 4 , the cylinder S 5  as the driving power source is actuated to extend the rod, so that the probe  27  descends toward the container  1 , together with the stopper plate  35  provided to the edge of the rod, and the attachment plate  39  attached to the stopper plate  35  by the guide bolts  36 . 
     Since the positioning unit  28  having the inclined guide portion  28   c  is attached to the lower portion of the attachment plate  29  by the attachment bolts  30 , the inclined guide portion  28   c  of the positioning unit  28  is brought into contact with the mouth portion  1   a  of the container  1  when the cylinder S 5  is actuated to extend the rod. Accordingly, as the positioning unit  28  is moved downward, the container  1  is forcibly moved along the conveyer  2  in the horizontal direction Y. After the axis center O of the container  1  is forcibly matched with the axis center O″ of the positioning unit  28 , the step portion  28   b  of the positioning unit  28  is placed on the upper surface of the container  1 , thereby covering the mouth portion  1   a  of the container  1  with the positioning unit  28 . The probe  27  is inserted into the inner stand wall  28   a  formed in the positioning unit  28 , with the axis center O′ of the probe  27  being matched with the axis center O″ of the positioning unit  28 . Because of this, the container  1  can be prevented from being wrongly judged to be a defective product due to the contact between the mouth portion  1   a  of the container  1  and the probe  27 . Thus, each inspection can be performed with high precision. Also, the descending position of the probe  27  is detected by the sensor c 5  in accordance with the size of the container  1 . 
     The positioning unit  28  is incorporated into the outer casing  29  having the inclined guide portion  29   a  extending from the inclined guide portion  28   c,  thereby making the inclined guide portions  28   c  and  29   a  as a contact portion long enough for the mouth portion  1   a  of the container  1 . Accordingly, the axis center O′ of the probe  27  can be quickly and accurately matched with the axis center O of the container  1 . The outer casing  29  also protects and reinforces the positioning unit  28 . 
     When the sensor c 5  detects the descending position, the water supply nozzle  41  supplies pure water w into the inner stand wall  28   a  of the positioning unit  28 , so that the total amount of pure water w reaches the height h 1  of the step portion  28   b  of the positioning unit  28  placed on the upper surface of the mouth portion  1   a,  as shown in FIG.  3 . There is only a short distance between the secondary water filling unit  13  and the leakage inspecting unit  20  at one of the inspecting spots K 1 , K 2 , K 3 , and K 4 , and the pure water supply position corresponds to the leakage inspecting position. Thus, the pure water w can be prevented from flowing from the concave portion  5  while the container  1  is being transported on the conveyer  2 . 
     The inner stand wall  28   a  formed in the positioning unit  28  has a larger diameter than the boundary surface T between the inner surface of the mouth portion  1   a  of the container  1  and the outer surface of the bush  6  attached to the mouth portion  1   a,  and is situated outside the boundary surface T. Thus, the amount of the additional pure water w supplied from the water supply nozzle  41  corresponds to the height h 1  of the positional unit  28  placed on the mouth portion  1   a.  (In FIG. 3, however, since the positioning unit  28  is incorporated into the outer casing  29 , the amount of pure water w seems to correspond to the height h 2  of the outer casing  29  mounted on the mouth portion  1   a .) 
     In the above manner, the probe  27  is inserted into the pure water w supplied into the concave portion  5  of the mouth portion  1   a  of the container and the inner stand wall  28   a  of the positioning unit  28  connected to the concave portion  5 , with the axis centers  0  and O′ corresponding to each other. Even if the probe  27  is brought into contact with the inner wall of the concave portion  5 , the container  1  can be prevented form being wrongly judged to be a defective product. The electric conductivity of the inspection water (pure water w) is measured so as to judge whether the beer B as the content liquid is leaking from the mouth portion  1   a  of the container  1 . 
     The pure water w is supplied into the inner stand wall  28   a  situated outside the upper surface of the boundary surface T between the inner surface of the mouth portion  1   a  of the container and the outer surface of the bush  6  attached to the mouth portion  1   a.  Accordingly, liquid leakage between the inner surface of the mouth portion  1   a  and the outer surface of the bush  6  can be detected through the inspection, as well as liquid leakage between the gas valve  9  and its valve seat in the sealing stopper unit  4 , and between the solution valve  11  and its valve seat. 
     After the electric conductivity of the water is measure, the cylinder S 5  is actuated to shorten the rod  34 . The stopper plate  35  mounted on the rod  34  and the probe  27  attached to the attachment plate  39  attached to the stopper plate  35  by the guide bolts  36  via the distance H then ascend to the original position. When the sensor c 6  detects the probe  27  back in its original position, the water supply nozzle  41  of the water supply unit  31  jets the pure water to wash the probe  27 . Here, the pure water w supplied from the water supply nozzle  41  surely washes not only the outer cylindrical portion  27 A of the probe  27 , but also the inner surface of the outer cylindrical portion  27 A and the pillar  27 B through the water passing hole  27   b  formed in the outer cylindrical portion  27 A of the probe  27 . 
     The air blow nozzle  43  of the air supply unit blows hot air or dry air to dry the washed probe  27 , thereby preparing the probe  27  for the next liquid leakage inspection. 
     The cylinder S 4  of the stopper unit  21  is then actuated to shorten the rod, and the transportation passage A of the conveyer  2  is opened to transport the inspected container  1 . If the container  1  is judged to be a defective product, the reject cylinder S 6  is actuated so that the rod is extended to discharge the defective container  1  to the reject conveyer  45 . 
     FIG. 6 illustrates another embodiment of the present invention. 
     In the first embodiment, the positioning unit  28  is attached to the attachment plate  39 , which is moved up and down by the rod  34  of the cylinder S 6  of the leakage inspecting unit  20 . When the container  1  is inspected, the positioning unit  28  is placed on the mouth portion  1   a  to supply the pure water w. 
     In the second embodiment, however, the positioning unit  28  is formed separately from the attachment plate  39 , to which the probe  27  is attached. 
     More specifically, when the positioning unit  28  is placed on the mouth portion  1   a  of the container  1 , a supporting unit  51  rotatable about a rotational axis  40  in the horizontal direction above the conveyer  2  moves the positioning unit  28  in the parallel direction with the mouth portion  1   a  of the container  1 . The positioning unit  28  is then moved up and down, and is placed on the mouth portion  1   a,  so that the axis center O″ of the positioning unit  28  corresponds to the axis center O of the mouth portion  1   a  of the container  1 . The water supply nozzle  41  then supplies the pure water w into the positioning unit  28  to judge whether the content liquid is leaking. After the inspection, the positioning unit  28  is removed from the container  1 . 
     In the above embodiments, the probe  27  moves up and down with respect to the mouth portion  1   a  of the container  1  being transported on the conveyer  2  by the driving force of the cylinder S 5 , and the probe  27  performs a leakage inspection to judge whether the content liquid is leaking from the mouth portion  1   a.  However, the container  1  may be moved up and down with respect to a fixed probe  27  to perform a leakage inspection. 
     Effects of the Invention 
     As described so far, in the present invention, the pure water injection position on the conveyer corresponds to the liquid leakage inspection position. In the inspection position, the pure water is injected into the concave portion formed in the mouth portion of the container and the positioning unit placed on the mouth portion, so that the pure water used in the inspection can be prevented from flowing out of the container during the transportation. The electric conductivity of the water can be measured with high accuracy, and defective products can be precisely detected. Thus, highly efficient inspection can be carried out. 
     In the prior art, liquid leakage cannot be detected from the boundary surface between the inner surface of the mouth portion and the outer surface of the bush. In the present invention, however, the positioning unit having an inner stand wall having a larger diameter than the boundary surface is placed on the mouth portion of the container, thereby enabling quick and accurate leakage detection from the boundary surface. 
     In the liquid leakage inspecting device of the present invention, the positioning unit is placed on the upper surface of the mouth portion of the container provided with the sealing stopper unit, and the probe is then inserted to measure the electric conductivity of the water to check for liquid leakage. The liquid leakage inspecting device of this structure is simple and does not require a large number of components. Accordingly, the production procedures can be simplified, and the production costs can be reduced. 
     Also, the movable guide bar is disposed on one side of the conveyer, so that the transportation width of the conveyer can be adjusted in accordance with the size of the container. Here, the axis center of the probe of the leakage inspecting unit is substantially matched with the center line situated in the longitudinal direction of the transportation width of the conveyer. Because of this, no strong force is required for holding the container being transported on the conveyer. Thus, the container can be prevented from being deformed or damaged. Also, the axis center matching, positioning, stopping, and transporting are all readily and surely performed. Thus, the container can be repeatedly used over a long period of time. 
     The inspection water for the liquid leakage inspection is supplied into the concave portion formed in the mouth portion of the container, with the water supply unit being situated exactly in the location of the concave portion. In this manner, the concave portion can be sufficiently filled with the inspection water, and the probe can be prevented from being situated outside the concave portion and from touching the inner surface of the concave portion. Thus, the liquid leakage inspection can be performed with high precision, without wrong judgements. 
     The movable guide bar formed on one side of the conveyer simplifies the structure of the liquid leakage inspecting device of the present invention. Thus, the production procedures can be simplified accordingly, and the production costs can be reduced. Also, it is easy to adjust the transportation width of the conveyer in accordance with the size of the container. 
     As described so far, the liquid leakage device of the present invention is provided with the water supply unit for supplying wash water into the upper position of the probe in the inspecting position, and the air supply unit for blowing dry air or hot air. Thus, the washing and drying of the probe for accurate inspection can be quickly carried out with little trouble. Also, the production procedures can be simplified, and the production and equipment costs can be reduced.

Technology Classification (CPC): 6