Abstract:
A fluid tank connector enables reliable separation of a plug and a socket by opposing the coupling force of a fluid sealing portion. The fluid tank connector is provided with a plug that is fit with play in the inner periphery of a fluid port of the fluid tank that stores a fluid, and a socket that is detachably connectable to the plug. The socket includes a sleeve that connects and disconnects the socket and the plug by being threadable on an external thread that is formed on the outer periphery of the fluid port. A pressing means is provided in the socket, and the pressing means applies a pressing force that separates the plug from the socket by opposing the coupling force of an 0-ring that seals the fluid path between the plug and the socket.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Japanese Patent Application No. 2008-010934 filed on Jan. 21, 2008, the contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a fluid tank connector for delivering a fluid that is inside a fluid tank to the outside thereof. 
       BACKGROUND OF THE INVENTION 
       [0003]    Generally, fluids such as high-purity chemical products for semiconductors or general-use chemical products are filled into fluid tanks such as polyethylene tanks at a production facility, and they are shipped after a lid has been attached to a fluid port for filling and discharging that is formed in this fluid tank. As a method for removing the fluid that has been stored in such a fluid tank, a siphon hose method is known in which a gas such as air is introduced into the container, and the fluid is fed to the outside of the container due to the gas pressure that is produced thereby. 
         [0004]    In this method, after removing the lid that was attached to the fluid port of the fluid tank, a plug is installed in the fluid port, and then a socket is connected in the plug. The plug is provided with a siphon hose, which forms a fluid path, and a gas supply duct. The socket is provided with a tube for removing fluid to the outside of the fluid tank and a tube for introducing gas. The socket enables the respective communication between its tube for removing fluid and the tube for introducing gas with the siphon hose and the gas supply duct of the plug. By connecting the socket into the plug, a fluid path for removing fluid and a gas path for introducing gas are formed. Such a fluid tank connector is disclosed, for example, in Japanese Unexamined Patent Application, First Publication No. 2002-59993. 
         [0005]    However, the above patent document discloses a plug that is fastened by being threaded onto an internal thread that has been formed on the inner periphery of the fluid port of the fluid tank. Therefore, the plug cannot be used in a container in which an external thread has been formed on the fluid port, that is, a container in which the thread for the installation of a cap that closes the fluid port is an external thread. 
         [0006]    Thus, in order to connect the plug and the socket to a fluid tank in which the fluid port has an external thread, a construction can be considered in which the plug is disposed at the inner periphery of the fluid port, and a sleeve that is provided on the socket is then threaded onto the external thread of the fluid port. In this case, an attachment method can be considered in which a plug that is provided with a catch is pressed into the fluid port under the assumption that the plug will not be removed therefrom. However, under these circumstances, such a method cannot meet the needs of a user who, for various reasons, wishes to remove the plug. In contrast, a construction can be considered in which the plug is fit into the inner periphery of the fluid port with some play so that the plug can be removed therefrom. However, in this construction, the coupling force (frictional force) of a fluid sealing portion (for example, an O-ring), which is provided between the plug and the socket when the fluid path is formed, is strong, and there is a concern that the plug may be pulled out from the fluid port along with the socket. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    In consideration of the circumstances described above, one object of the present invention to provide a fluid tank connector that enables the reliable execution of the separation of the plug and the socket by opposing the coupling force of the fluid sealing portion. 
         [0008]    In order to attain the object described above, the present invention provides the following solutions. 
         [0009]    The fluid tank connector according to one mode of the present invention is provided with a plug and a socket. The plug is disposed at the inner periphery of a fluid port of a fluid tank that stores a fluid and the socket can detachably connect to the plug. The socket includes a sleeve that detachably connects to the plug due to being threadable on a thread groove that is formed in the outer periphery of the fluid port. In a fluid delivery state in which the plug and the socket have been connected, a fluid path that delivers fluid from the fluid tank and a gas path that supplies gas into the fluid tank are formed. A characterizing feature of the fluid tank connector is that pressing means are provided that apply a pressing force that separates the socket and the plug by opposing the coupling force of a fluid sealing portion that seals the fluid path between the plug and the socket. 
         [0010]    In the case in which the coupling force (frictional force) of the fluid sealing portion that is provided between the plug and the socket is strong, when the socket is to be separated from the plug, there is a concern that the connection between the plug and the socket will not be released and that the socket and the plug will both be removed from the fluid port of the fluid tank. In response to this, in this mode, because a pressing means is provided that separates the plug by opposing (overcoming) the coupling force of the fluid sealing portion, when the socket is removed from the plug, the socket can be reliably separated from the plug while the plug continues to remain connected to the fluid tank side. 
         [0011]    Moreover, preferably, the pressing means are provided in the socket. It is thereby possible to simplify the structure of the plug. 
         [0012]    Furthermore, in the fluid tank connector of the above mode, the plug may be fit with play in the fluid port. 
         [0013]    There are cases in which, for various reasons, a user may wish to remove a plug from the fluid port of the fluid tank. In these cases, preferably, the plug is fit with play into the fluid port. Even when the plug is fit with play into the fluid port in this manner, it is possible to reliably separate the plug from the socket by using the pressing means, and thus, it is possible to avoid removing the plug from the fluid tank connected to the socket. 
         [0014]    Furthermore, in the fluid tank connector in the mode described above, a gas sealing portion that seals the fluid path may be provided between the plug and the socket, and this gas sealing portion may be provided with a replaceable sealing member that is provided on the socket side. 
         [0015]    The replaceable sealing member is provided on the socket side as a gas sealing portion. By replacing the sealing member, it is possible to maintain the gas sealing portion over a long period of time. In particular, because it is often the case that the socket is connected and attached to a facility side that supplies a fluid and frequent replacement cannot be carried out, it is possible to improve the serviceability by providing a replaceable sealing member in advance at the socket side. 
         [0016]    Note that instead of the above mode, a convex portion (edge) may be formed on the socket side, and sealing may be carried out by pressing this convex portion against the plug side. 
         [0017]    According to the present invention, because pressing means are provided that separate the plug by opposing (overcoming) the coupling force of the fluid sealing portion, when the socket is removed from the plug, it is possible to reliably separate the socket from the plug while the plug continues to remain disposed on the fluid tank side. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0018]      FIG. 1  is a cross-sectional view that shows the area around the fluid port of the fluid tank that is provided with the fluid tank connector according to an embodiment of the present invention. 
           [0019]      FIG. 2  is a plan view of the fluid tank connector in  FIG. 1 . 
           [0020]      FIG. 3  is an enlarged cross-sectional view of the fluid tank connector in  FIG. 1 . 
           [0021]      FIG. 4  is a cross-sectional view that shows the state in which the socket is partially separated from the plug. 
           [0022]      FIG. 5  is a cross-sectional view showing the state in which the socket has been separated from the plug. 
           [0023]      FIG. 6  is an enlarged cross-sectional view of the fluid tank connector that shows a modified example that uses packing as the gas sealing portion. 
           [0024]      FIG. 7A  is an enlarged cross-sectional view that shows the gas sealing portion and the edge seal. 
           [0025]      FIG. 7B  is an enlarged cross-sectional view that shows the gas sealing portion and shows the packing seal. 
           [0026]      FIG. 8  is a cross-sectional view that shows a comparative example of the present invention, and shows the state in which the plug is separated along with the socket from the fluid port of the fluid tank. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    An embodiment of the fluid tank connector according to the present invention will be explained with reference to the drawings. 
         [0028]      FIG. 1  shows a fluid tank connector  10  that is installed in a fluid port  2  of a fluid tank  1 . The fluid tank connector  10  is provided with a plug  20  that is accommodated inside the fluid port  2  and a socket  50  that is detachably connectable to the plug  20 . The fluid tank connector  10  uses a siphon hose method, in which, in order to remove the fluid that is stored inside the fluid tank  1 , a gas, such as air, is introduced to the inside of the fluid tank  1  and the fluid is fed to the outside of the fluid tank  1  due to the gas pressure that is produced thereby. 
         [0029]    The fluid tank  1  that has been filled with a chemical fluid (fluid), such as a high-purity chemical product for semiconductors, is a molded product made, for example, of a chemical-resistant resin. The fluid port  2 , which is provided at the top of the fluid tank  1 , is an open portion that is used when a fluid such as a chemical product and the like is filled into the inside of the fluid tank  1  or when a chemical product inside of the fluid tank  1  is removed. 
         [0030]    The fluid port  2  is a nozzle having a shape of a cylinder that opens at the upper end thereof and projects upward from the body  1   a  of the fluid tank  1 , and although not shown, the open portion of the fluid tank  1  can be sealed by attaching a cap. The cap in this case is of a type in which an internal thread is formed on the inner peripheral surface thereof, and the cap is installed by being threaded onto the external thread  3  that is formed on the outer peripheral surface of the fluid port  2 . 
         [0031]    The plug  20  is a molded part made of resin and the like. It is inserted from above into the opening of the fluid port  2  and installed so as to be fitted with play. Specifically, the bottom end portion of the plug  20  has a tubular shape that provides neither a catch that engages the inner periphery of the fluid port  2  nor a thread that is threaded. 
         [0032]    The plug  20  is provided with gas supply ducts  22  and a siphon hose  23 , which are formed in the substantially tube shaped plug body  21 . 
         [0033]    The gas supply ducts  22  are ducts for supplying a gas that is introduced from the outside into the inside of the fluid tank  1 . These gas supply ducts  22  are holes that pass through the plug body  21  in an axial direction, and they are provided in plurality so as to surround the siphon hose  23  that is disposed at the axial center of the plug body  21 . 
         [0034]    The siphon hose  23  is a path through which the fluid inside the fluid tank  1  is removed due to being pushed out by the pressure of the gas, and extends from the plug body  21  to the proximity of the bottom surface of the fluid tank  1 . The necessary length of the illustrated siphon hose  23  is ensured by coupling an extension tube  23   a  to a portion that is integrally formed with the plug body  21 . Note that in the following explanation, except where necessary, the entire tube, including the extension tube  23   a,  is referred to as the siphon hose  23 . 
         [0035]    In addition, at the upper end inlet portion of the siphon hose  23 , a valve actuating portion  25  (refer to  FIG. 5 ) is provided that pushes up and opens a fluid outflow valve  55  that is provided in the socket  50 . The upper end inlet portion is only partially closed off by this valve actuating portion  25  (in particular, the axially central portion) because penetrating portions  25   a  (refer to  FIG. 5 ), which serve as fluid paths for the siphon hose  23 , are provided. The lower end portion of the valve  55  abuts and can thereby be pressed upward by the valve actuating portion  25 . Note that, depending on the type of the socket  50  that is used in combination with the plug  20 , there are cases in which this valve actuating portion  25  is unnecessary. 
         [0036]    In addition, the plug  20  described above is provided with a flange portion  29  that is formed so as to face outward from the upper end portion of the plug body  21  and that is seated on the upper end surface of the fluid port  2 . In addition, on the lower surface of the flange portion  29 , where the flange portion  29  is in close contact with the upper surface of the fluid port  2 , packing  31  is provided over the entire periphery thereof. This packing  31  functions as a sealing portion that prevents the discharge of gas between the fluid tank  1  and the plug  20  during the removal of fluid. In addition, during the transport of the fluid tank  1  or in the event that the fluid tank  1  is overturned, this packing  31  also functions as a seal that prevents the discharge of gas and fluid between the fluid tank  1  and the plug  20 . 
         [0037]    Furthermore, preferably, a ring-shaped convex portion (not illustrated) is also formed on the upper surface of the flange portion  29  described above so as to extend over the entire periphery thereof. When a cap is attached after the plug  20  has been press fit, this convex portion functions as a sealing portion that prevents the discharge of fluid caused by the fluid passing through the gas supply duct  22  due to the agitation of the fluid surface and the like during the transport of the fluid tank  1 , or in the event that fluid tank  1  is overturned. 
         [0038]    In the fluid tank connector  10  having the structure described above, as shown in  FIG. 1 , the socket  50  is coupled with the plug  20  when the fluid inside the fluid tank  1  is removed. 
         [0039]    The socket  50  is provided with a socket body  51  and a sleeve  60  that fastens this socket body  51  to the fluid tank  1  so as to be inserted at a predetermined position in the plug  20 . The socket body  51  is provided with a fluid removal path  52  and a gas path  53  (refer to  FIG. 2 ) in a substantially columnar member. Note that the gas path  53  is not shown in the longitudinal cross-sectional view in  FIG. 1  and the like. 
         [0040]    The sleeve  60  can rotate with respect to the outer peripheral portion of the socket body  51 . In addition, a concavoconvex engaging portion  61  that limits the movement of the socket body  51  in an axial direction is provided on the sleeve  60 , and an internal thread  62  (refer to  FIG. 5 ) is formed on the lower end portion side of the inner peripheral surface of the sleeve  60 , and this internal thread  62  is threaded onto the external thread  3  of the fluid port  2 . Specifically, when attaching the socket  50 , after the socket body  51  is inserted into the plug  20  at a predetermined position, when the sleeve  60  is rotated to thread and fasten the internal thread  62  on the external thread  3 , the socket body  51  is pulled down by the engaging portion  61  and is fastened so as to be in close contact with the plug  20 . Thereby, the plug  20 , which is fit with play into the fluid port  2 , is fastened together with the socket  50 . Specifically, the flange portion  29  of the plug  20  is interposed between the upper end surface of the fluid port  2  and the sleeve  60 , and the plug  20  is thereby anchored to the fluid port  2 . 
         [0041]    The fluid removal path  52  is an axial through-hole that is formed at an axial center position in the socket body  51 , and a connecting opening  52   a  for an external duct, through which fluid is discharged, is provided at the upper end portion thereof. When coupled with the plug  20 , this fluid discharge path  52  forms an integrated fluid path by communicating with the siphon hose  23  that is inserted into the fluid tank  1 . Note that an internal thread is formed on the illustrated connecting opening  52   a.  This internal thread threads and thereby couples with a plug (not illustrated) that is installed on one end of an external duct for fluid discharge. 
         [0042]    The gas path  53  is a through-hole that is formed substantially parallel to the fluid removal path  52  described above. One end of the gas path  53  is connected to a gas supply source and the other end thereof communicates with the gas supply ducts  22  of the plug  20 . An integrated gas path is formed by the gas path  53  and the gas supply ducts  22 . A connecting opening  53   a  (refer to  FIG. 2 ) for an external duct for a gas supply is provided on the upper end portion of the gas path  53 , which is connected to a gas supply source. Note that an internal thread is formed on the illustrated connecting opening  53   a.  This internal thread threads onto and thereby couples with a plug (not illustrated)) that has been installed on one end of the external duct for gas supply. 
         [0043]    In addition, the illustrated socket  50  is of a type in which a valve  55  is provided in the fluid removal path  52 . Because the valve body  54 a (refer to  FIG. 3 ) is normally urged downward by the spring  54   b  (refer to  FIG. 3 ), as shown in  FIG. 5 , when the plug  20  is not coupled, this valve  55  closes the fluid removal path  52  due to the valve body  54   a  being brought into close contact with the valve seat. 
         [0044]    In contrast, as shown in  FIG. 1 , when the socket  50  described above is installed at a predetermined position in the plug  20 , the valve actuating portion  25  that is provided on the plug  20  side presses the valve body  54   a  upward by opposing the urging force of the spring  54   b,  and thus the close contact between the valve body  54   a  and the valve seat is released. Due to the valve  55  being opened in this manner, a fluid path is formed that discharges fluid to the outside of the fluid tank  1  by the fluid passing through the siphon hose  23  and the fluid discharge path  52 . 
         [0045]    In the state that is shown in  FIG. 1 , in which the socket  50  is installed and fastened in the plug  20 , the fluid path that communicates the space between the siphon hose  23  and the fluid removal path  52  is sealed by the O-ring  58  (the fluid sealing portion). The O-ring  58  is arranged on the inner periphery of a center hole portion  59  (refer to  FIG. 5 ) of the socket  50 , and a center tube portion  24  (refer to  FIG. 5 ) of the plug  20  is inserted into this center hole portion  59 . The coupling force between the socket  50  and the center tube portion  24  of the plug  20  is ensured by the elastic force of this O-ring  58 . 
         [0046]    In addition, a gas path communicates from the gas path  53  to the gas supply duct  22 . The gas path is sealed off from the fluid path side by the O-ring  58  described above at the inner periphery of this gas path, and at the outer periphery of the gas path, a seal is formed due to the gas sealing portion  30  (refer to  FIG. 1 ) that is formed by the step portion of the socket body  51  abutting the step portion of the plug body  21 . Specifically, as shown in  FIG. 7A , a convex portion (edge)  51   b,  which projects toward the plug body  21  side and has a corner portion on the distal end thereof, is formed on the step portion  51   a  of the socket body  51  over the entire periphery thereof. The gas seal is ensured by the distal end of this convex portion  51   b  being press fit against the step portion  21   a  of the plug body  21 . 
         [0047]    Note that, as shown in  FIG. 7B , a gas sealing portion may be provided by arranging a removable packing (sealing member)  70  on the socket body  51  side, and providing a convex portion  21   b  that is press fit against this packing  70  on the step portion  21  a of the plug body  21 . The structure of the socket  50  that is provided with such as packing  70  is shown in  FIG. 6 . Examples of the packing  70  that can be advantageously used include polyethylene, PTFE, referred to as Teflon™, fluorocarbon rubber, and silicone rubber and the like. Because it is often the case that the socket  50  is connected and attached to a facility side that supplies the fluid and frequent replacement cannot be carried out, it is possible to improve the serviceability by providing in advance such replaceable packing  70  on the socket  50  side. 
         [0048]    The sealed state described above is reliably maintained by the sleeve  60  of the socket  50  being threaded onto and attached to the fluid port  2  of the fluid tank  1 . 
         [0049]    As shown in  FIG. 1 , pressing means  80  for separating the socket  50  from the plug  20  are provided in the socket body  51 . As shown in the enlarged view in  FIG. 3 , each pressing means  80  is provided with a pressing rod  82  that can reciprocally approach and retract from the plug  20 , and a compression spring  83  that urges the pressing rod  82  downward (i.e., toward the plug  20  side). The upper end of each compression spring  83  is fastened by a stopper  84  that is fastened to the upper end of the socket body  51 . 
         [0050]    As shown in  FIG. 2 , the two pressing means  80  are symmetrically provided such that the fluid removal path  52 , which is provided at the center, is interposed therebetween. In the connected state that is shown in  FIG. 1 , the distal end (in the figure, the lower end) of each pressing rod  82  presses the plug  20  downward due to the action of the compression spring  83  while abutting the upper end surface of the plug  20 . The pressing force due to these pressing rods  82  is larger than the coupling force (i.e., the frictional force) between the plug  20  and the socket  50  that is caused by the O-ring  58  described above. Specifically, by opposing (overcoming) the coupling force caused by the O-ring  58  that forms the fluid sealing portion, a pressing force sufficient to separate the plug  20  and the socket  50  is applied by the pressing rods  82 . Thereby, when the socket  50  is removed from the plug  20 , it is possible to remove the socket  50  while the plug  20  continues to remain inside the fluid port  2 . 
         [0051]    Next, the operation of the fluid tank connector  10  having the structure described above during connection and release will be explained. 
         [0052]    As shown in  FIG. 1 , the chemical fluid inside the fluid tank  1  is removed (fluid delivery state) while the plug  20  and the socket  50  are connected. When the removal of the fluid has terminated, the sleeve  60  of the socket  50  is rotated, and the threaded state between the fluid port  2  and the sleeve  60  is loosened. The socket body  51  is thereby separated from the plug  20  to exhibit the state that is shown in  FIG. 4 . As shown in  FIG. 4 , when the socket body  51  is separated from the plug  20 , the pressing rods  82  of the pressing means  80  press the plug body  21  downward, and thus, the coupling force between the plug body  21  and the socket body  51  caused by the O-ring  58  that forms the fluid sealing portion is opposed (overcome), and only the socket body  51  moves upward while the plug body  21  continues to remain inside the fluid port  2 . 
         [0053]    Furthermore, when the sleeve  60  is rotated to release the threading with the fluid port  2 , as shown in  FIG. 5 , the socket  50  is completely separated from the plug  20 . 
         [0054]    As a comparative example,  FIG. 8  shows a fluid tank connector that is not provided with the pressing means  80  such as the one in the present invention. When the pressing means  80  are not provided, as explained with reference to  FIG. 4 , it is not possible to separate the plug body  21  from the socket body  51  because the coupling force caused by the O-ring  58  cannot be overcome, and thus the plug  20  is removed from the fluid tank  1  along with the socket  50 . In particular, in the present embodiment, because a structure is used in which the plug  20  is fit with play into the fluid port  2 , the plug  20  is easily removed along with the socket. 
         [0055]    In the manner described above, according to the present embodiment, because the pressing means  80  are provided in the socket  50  and separate the plug  20  from the socket  50  by opposing the coupling force caused by the O-ring  58  that forms the fluid sealing portion, when the socket  50  is separated from the plug  20 , the socket  50  can be reliably separated from the plug  20  while the plug  20  continues to remain connected to the fluid tank  1  side. 
         [0056]    Note that in the embodiment described above, when fluid is removed from the inside of the fluid tank  1 , gas pressure is supplied into the fluid tank  1 , the pressure acts on the fluid surface, and the fluid is pressurized and removed due to this pressure (siphon hose method). However, it is also possible to connect piping to the fluid removal path  52  of the socket  50  and discharge the fluid by using a pump. In this case, the gas path  53  serves as a path for supplying and replacing the air and the like inside the fluid tank  1  by an amount equivalent to the decrease of the fluid.