Abstract:
An oxygen-enricher oxygen tank unit includes a single oxygen tank body, to which a pair of nitrogen absorption containers, which alternately receive a supply of compressed air, are connected; a check valve provided between each of the pair of nitrogen absorption containers and the oxygen tank body, wherein each check valve allows gas to flow from an associated nitrogen absorption container to the oxygen tank body, and does not allow gas to flow in a reverse direction thereto; and a pressure-reducing valve, having an oxygen outlet, which is connected to the oxygen tank body. At least one of the pressure-reducing valve and a pair of nitrogen absorption container connector-cylinders, which is provided with the check valve, is directly attached to a body-wall surface of the oxygen tank body. Hence, the structure around the oxygen tank body is simplified and unitized.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Japanese patent application No. 2011-067250, filed on Mar. 25, 2011 and PCT Application No. PCT/JP2012/053620, filed on Feb. 16, 2012, the disclosures of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to an oxygen tank unit which is used in a medical oxygen enricher. 
       BACKGROUND ART 
       [0003]    Oxygen enrichers, which generate oxygen by using an absorption material (typically zeolite) which selectively absorbs nitrogen from air, are in practical use as medical oxygen enrichers. 
         [0004]      FIG. 10  shows a typical piping system diagram of such an oxygen enricher  10 . Compressed air that has been compressed in a compressor  11  is supplied to each inlet of a pair of nitrogen absorption containers  17  and  18  via conduits  12 ,  13 ,  14  and pressurized switching valves (electromagnetic ON/OFF valves)  15  and  16 . Outlets of the nitrogen absorption containers  17  are connected to a single oxygen tank  24  via conduits  19 ,  20 ,  21  and check valves  22  and  23 , and the oxygen tank  24  is connected to an air outlet  27  via a conduit  25  and a pressure-reducing valve (regulator)  26 . The nitrogen absorption containers  17  and  18  are filled with, e.g., zeolite (powder or granules), which constitutes a nitrogen absorption material which selectively absorbs nitrogen in the air inside the nitrogen absorption containers  17  and  18 . The check valves  22  and  23  are one-way valves which allow gas (air) to flow from the nitrogen absorption containers  17  and  18  to the oxygen tank  24  and do not allow gas to flow in the reverse direction. 
         [0005]    Conduits  31  and  32  are connected to the conduits  13  and  14  at the downstream sides of the pressurized switching valves  15  and  16  (the inlet sides of the nitrogen absorption containers  17  and  18 ), respectively, and pressure-reducing switching valves (electromagnetic ON/OFF valves)  33  and  34  are provided on the conduits  31  and  32 , respectively. The outlet sides of the pressure-reducing switching valves  33  and  34  are merged at a conduit  35  and are connected to an exhaust muffler  36 . 
         [0006]    The conduits  19  and  20  are connected to each other via a conduit  37  at the upstream sides of the check valves  22  and  23  (the outlet sides of the nitrogen absorption containers  17  and  18 ), and a purge valve  40 , sandwiched in between throttle valves (orifices)  38  and  39 , is provided in the conduit  37 . 
         [0007]    The ON/OFF control of the pressurized switching valves  15  and  16 , the pressure-reducing switching valves  33  and  34 , and the purge valve  40  of the oxygen enricher  10  are carried out in accordance with the time chart shown in  FIG. 11 . Namely, when the pressurized switching valve  15  ( 16 ) opens, the pressurized switching valve  16  ( 15 ) is closed, and upon a predetermined amount of time lapsing from when the pressurized switching valve  15  ( 16 ) opens, the pressure-reducing switching valve  34  ( 33 ) opens. Since the pressurized switching valve  16  ( 15 ) is closed when the pressurized switching valve  15  ( 16 ) opens, pressurized air from the compressor  11  is fed only to the nitrogen absorption container  17  ( 18 ), so that nitrogen in the air is absorbed in the absorption material inside the nitrogen absorption container  17  ( 18 ) and a high concentration of oxygen is fed through the conduit  19  ( 20 ). When the pressure inside the conduit  19  ( 20 ) exceeds a predetermined value, the check valve  22  ( 23 ) opens so that highly concentrated oxygen is accumulated inside the oxygen tank  24 . 
         [0008]    On the other hand, upon a predetermined amount of time lapsing after the pressurized switching valve  15  ( 16 ) has opened, the pressure-reducing switching valve  34  ( 33 ) is opened, and furthermore, upon a predetermined amount of time lapsing after the pressure-reducing switching valve  34  ( 33 ) has opened, the purge valve  40  is opened. Consequently, the highly concentrated oxygen on the high-pressure side is supplied to the nitrogen absorption container  18  ( 17 ), which was on the low-pressure side, from the upstream side and flows in reverse to the nitrogen absorption container  18  ( 17 ). Accordingly, the nitrogen that was absorbed in the absorption material inside the nitrogen absorption container  18  ( 17 ) is discharged to the conduit  32  ( 31 ) with the highly concentrated air, and the gas containing the discharged nitrogen is discharged via the conduit  35  and the exhaust muffler  36 . 
         [0009]    The highly concentrated oxygen that has accumulated in the oxygen tank  24  is supplied to the patient from the air outlet  27  after the pressure thereof is reduced by the pressure-reducing valve (regulator)  26 . Namely, since the pressure inside the oxygen tank  24  fluctuates greatly as the result of high-pressure highly concentrated oxygen being alternately supplied from the nitrogen absorption containers  17  and  18 , highly concentrated oxygen having a reduced pressure fluctuation via the pressure-reducing valve  26  is supplied to the patient. The above description is the operating principle of the oxygen enricher  10 . 
       SUMMARY OF INVENTION 
     Technical Problem  
       [0010]    The oxygen enricher  10 , which operates according to the above-described operating principle, requires a large number of conduits for connecting the compressor  11 , the pressurized switching valves  15  and  16 , the pressure-reducing switching valves  33  and  34 , the check valves  22  and  23 , the purge valve  40 , the oxygen tank  24  and the pressure-reducing valve  26 , etc., and accordingly, the entire device becomes large, and also incurs an increased assembly cost. 
         [0011]    An object of the present invention is to achieve an oxygen tank unit for an oxygen enricher which can simplify and unitize the configuration among the oxygen tank  24 , the check valves  22  and  23 , and the pressure-reducing valve  26  of the oxygen enricher  10 , having the above-described operating principle, with special attention to the configuration around the oxygen tank  24 . 
       Solution to Problem  
       [0012]    The present invention is characterized by an oxygen-enricher oxygen tank unit, including a single oxygen tank body, to which a pair of nitrogen absorption containers, which alternately receive a supply of compressed air, are connected; a check valve provided between each of the pair of nitrogen absorption containers and the oxygen tank body, wherein each check valve allows gas to flow from an associated nitrogen absorption container to the oxygen tank body, and does not allow gas to flow in a reverse direction thereto; and a pressure-reducing valve, having an oxygen outlet, which is connected to the oxygen tank body. At least one of the pressure-reducing valve and a pair of nitrogen absorption container connector-cylinders, which is provided with the check valve, is directly attached to a body-wall surface of the oxygen tank body. 
         [0013]    In an embodiment of the present invention, a bacteria filter unit can be connected to an outlet of the pressure-reducing valve of the oxygen tank body. 
         [0014]    The oxygen tank body can be further provided with at least one of an oxygen pressure sensor and an oxygen concentration sensor. 
         [0015]    It is desirable for the oxygen concentration sensor to be provided at the outlet of the pressure-reducing valve. 
         [0016]    Each of the pair of nitrogen absorption container connector-cylinders, provided with the check valve, can, for example, be provided with a check valve unit which is inserted into a stepped through-hole portion in the body-wall surface of the oxygen tank body, and a nitrogen absorption container connector-pipe which is mounted onto the check valve unit in a coaxial manner therewith. 
         [0017]    In an embodiment of the present invention, the pressure-reducing valve includes a main housing and a sub-housing which is connected to the main housing. The main housing is mounted on the body-wall surface of the oxygen tank body, and includes a primary pressure-introduction channel which is communicatively connected with the through-hole of the body-wall surface of the oxygen tank body, a secondary pressure-outlet channel, and a main valve which is provided between the primary pressure-introduction channel and the secondary pressure-outlet channel. The sub-housing supports an operational diaphragm assembly between the sub-housing and the main housing, and forms a secondary pressure chamber which is communicatively connected with the secondary pressure-outlet channel. The operational diaphragm assembly and the main valve operate in cooperation with each other so that the main valve opens and closes in accordance with a fluctuation in pressure in the secondary pressure chamber. 
         [0018]    A lower housing, of the bacteria filter unit, which is communicatively connected with the secondary pressure-outlet channel, can be mounted onto the main housing of the pressure-reducing valve, and an upper housing, which sandwiches a bacterial filter between the upper housing and the lower housing, can be mounted onto the lower housing. 
         [0019]    In an embodiment, the main housing is supported to be detachably attached to the oxygen tank body via bayonet claws. 
       Advantageous Effects of Invention  
       [0020]    According to the present invention, in an oxygen enricher which utilizes a pair of nitrogen absorption containers, since at least one of the pressure-reducing valve and the pair of nitrogen absorption container connector-cylinders, which are provided with a check valve, are directly attached to a body-wall surface of a oxygen tank, the configuration among the oxygen tank body, the check valve and the pressure-reducing valve can be simplified and unitized. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]      FIG. 1  is a perspective view showing an embodiment of an oxygen tank unit, according to the present invention, which is utilized in an oxygen enricher. 
           [0022]      FIG. 2  is a side elevation of the embodiment of an oxygen tank unit. 
           [0023]      FIG. 3  is a sectional view taken along the line III-III shown in  FIG. 2 . 
           [0024]      FIG. 4  is an enlarged view of the IV-section shown in  FIG. 3 . 
           [0025]      FIG. 5  is a perspective view of the section in  FIG. 4 . 
           [0026]      FIG. 6  is an enlarged view of the IV-section shown in  FIG. 3 . 
           [0027]      FIG. 7  is a perspective view of the section in  FIG. 6 . 
           [0028]      FIG. 8  is a circuit diagram of the oxygen tank unit of the present invention. 
           [0029]      FIG. 9  is a perspective view of the fundamental components, showing another embodiment of an oxygen tank unit, according to the present invention. 
           [0030]      FIG. 10  is a circuit diagram of an oxygen enricher which constitutes a premise to the present invention. 
           [0031]      FIG. 11  is a timing chart showing the ON/OFF timing of each valve of the oxygen enricher of  FIG. 10 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]      FIGS. 1 through 8  show a first embodiment of an oxygen-enricher oxygen tank unit  50  according to the present invention. As shown in  FIGS. 1 through 3 , the oxygen-enricher oxygen tank unit  50  includes a compound-resin oxygen tank body  51 . The oxygen tank body  51  includes half bodies  52  and  53 , and respective flanges  52   h  and  53   h  are joined together with fixing bolts  54  to form an air-tight space therein. 
         [0033]    The tank half body  52  includes a high end-wall  52 A and a low end-wall  52 B which are mutually parallel to each other and have different heights. A pair of in-built check-valve cylinders (nitrogen absorption container connector-cylinders)  60  are mounted onto the high end-wall  52 A so as to be orthogonal to the high end-wall  52 A, and a pressure-reducing valve (regulator)  70  is mounted onto the low end-wall  52 B. 
         [0034]      FIGS. 4 and 5  show the detailed structure of the in-built check-valve cylinders (nitrogen absorption container connector-cylinders)  60 . A pair of stepped through-holes  55 , which correspond to the pair of in-built check-valve cylinders  60 , are formed in the high end-wall  52 A. Each of these stepped through-holes  55  includes a small-diameter stepped portion  56  and a large-diameter stepped portion  57 . Each in-built check-valve cylinder  60  includes a check valve unit  62  which is air-tightly inserted into the small-diameter stepped portion  56  of the stepped through-holes  55  via an O-ring  61 , and a nitrogen absorption container connector-pipe  64  which is air-tightly inserted into the large-diameter stepped portion  57  via an O-ring  63 . The check valve unit  62  is configured of a flat circular valve-seat  62   a  and a valve body  62   b . A valve-body holding hole  62   c  is formed in the flat circular valve-seat  62   a , at the central portion thereof, and a plurality of through-holes  62   d  are formed in a surrounding portion of the flat circular valve-seat  62   a . The valve body  62   b  includes a shaft portion  62   f  which is insertably held in the valve-body holding hole  62   c , and a valve portion  62   g  which normally closes over the through-holes  62   d . The valve portion  62   g  of the valve body  62   b  closes the through-holes  62   d  by the pressure inside the oxygen tank body  51 , and the valve body  62   b  is installed in the valve-body holding hole  62   c  so as to deform in a direction to open the through-holes  62   d  by pressure outside the oxygen tank body  51 . A large-diameter flange  64   a , which is inserted into the large-diameter stepped portion  57 , is formed on the bottom end of the nitrogen absorption container connector-pipe  64 . 
         [0035]    The pair of in-built check-valve cylinders  60  have the same structure, and are fixed to the high end-wall  52 A of the tank half body  52  by a single mounting plate  65 . Namely, a pair of through-holes  65   a  corresponding to the pair of nitrogen absorption container connector-pipes  64  is formed in the mounting plate  65 , and the mounting plate  65  is mounted onto the high end-wall  52 A by mounting screws  66  with the pair of nitrogen absorption container connector-pipes  64  inserted into the pair of through-holes  65   a . The mounting plate  65  mounts, while pressing, the check valve units  62  into the small-diameter stepped portions  56  of the stepped through-holes  55 , via the large-diameter flanges  64   a . Screw-bearing seats  52 C ( FIGS. 3 and 4 ), into which the mounting screws  66  fixedly screw-engage, are formed on the inner surface of the high end-wall  52 A of the tank half body  52 . 
         [0036]      FIGS. 6 and 7  show a detailed structure of the pressure-reducing valve  70 . A through-hole  58  is formed in the low end-wall  52 B of the tank half body  52 . The pressure-reducing valve  70  includes a main housing  71  and a sub-housing  72 . The main housing  71  is mounted to the low end-wall  52 B via mounting screws  73  ( FIG. 7 ). Other screw-bearing seats  52 C ( FIGS. 3 and 6 ), into which the mounting screws  73  fixedly screw-engage, are formed on the inner surface of the low end-wall  52 B. 
         [0037]    The main housing  71  includes a primary pressure-introduction channel  71   a , which is directly communicatively-connected to the through-hole  58  via an O-ring  79 , and a secondary pressure-outlet channel (oxygen outlet)  71   b . A main valve  74  is provided in a communicative-connection channel that communicatively connects the primary pressure-introduction channel  71   a  with the secondary pressure-outlet channel  71   b . The main valve  74  is a valve that normally shuts-off the communicative connection between the primary pressure-introduction channel  71   a  and the secondary pressure-outlet channel  71   b  by a valve-closing spring  74   a.    
         [0038]    The sub-housing  72  defines a secondary pressure chamber  72   a  which sandwiches an operational diaphragm assembly  75  between the sub-housing  72  and the main housing  71 . The secondary pressure chamber  72   a  is communicatively connected with the secondary pressure-outlet channel  71   b  via a connection channel  71   c . The operational diaphragm assembly  75  includes a diaphragm  75   a , and an operational piston  75   b  that is mounted at a central portion of the diaphragm  75   a . The operational piston  75   b  opens and closes in cooperation with the main valve  74  in accordance with the fluctuation in pressure of the secondary pressure chamber  72   a  (secondary pressure-outlet channel  71   b ). Specifically, when the pressure inside the secondary pressure-outlet channel  71   b  lowers, the operational diaphragm assembly  75  moves the main valve  74  in the valve-closing direction against the force of the valve-closing spring  74   a , and when the pressure inside the secondary pressure-outlet channel  71   b  increases, the operational diaphragm assembly  75  conversely moves away from the main valve  74  to thereby close the main valve  74 . As a result of this operation being repeated in accordance with the pressure fluctuation of the secondary pressure-outlet channel  71   b , the pressure discharging from the secondary pressure-outlet channel  71   b  is maintained substantially constant. The discharge pressure of the secondary pressure-outlet channel  71   b  can be adjusted by adjusting the force of a pressure-adjustment spring  77 , which is exerted on the operational diaphragm assembly  75 , by rotating a pressure-adjustment screw  76 . 
         [0039]    A bacteria filter unit  80 , which is communicatively connected to the secondary pressure-outlet channel  71   b , is mounted on the main housing  71  of the pressure-reducing valve  70 . The bacteria filter unit  80  supports, in a sandwiched manner, a bacterial filter  83  in between a lower housing  81  and an upper housing  82 . A gas inlet  84  which is communicatively connected with the secondary pressure-outlet channel  71   b  is formed in the insulator  81 , and a gas discharge outlet (oxygen outlet)  85  for discharging gas (oxygen) passing through the bacterial filter  83  is mounted on the upper housing  82 . The lower housing  81  of the bacteria filter unit  80  is mounted onto the main housing  71  of the pressure-reducing valve  70  via mounting screws  86  while maintaining an air-tight state and sandwiching an O-ring  88  between the inlet of the gas inlet  84  and the outlet of the secondary pressure-outlet channel  71   b . The upper housing  82  is mounted onto the lower housing  81 , which is mounted onto the main housing  71 , by mounting screws  87  to sandwich the bacterial filter  83  therebetween. Screw seats  71   d  ( FIG. 7 ), into which the mounting screws  86  are screw-engaged, are formed in the main housing  71 . The bacterial filter  83  is a commonly known filter which removes impurities such as bacteria that are contained in the oxygen that passes therethrough. The bacterial filter  83  is replaced after being in use for a predetermined amount of time. 
         [0040]      FIG. 8  is a circuit diagram of the oxygen-enricher oxygen tank unit  50  in which the in-built check-valve cylinders  60  and the pressure-reducing valve  70  (and the bacteria filter unit  80 ) are mounted onto the high end-wall  52 A and the low end-wall  52 B, respectively. The pair of nitrogen absorption container connector-pipes  64  are connected to the nitrogen absorption containers  17  and  18 , which are described in  FIG. 10 , by a suitable conduit means, and the oxygen from the gas discharge outlet  85  is given to the user&#39;s (patient&#39;s) mouth (nose) via a soft supply tube or aspirator. As shown in  FIG. 8 , it is desirable for an oxygen concentration sensor  90  to be provided downstream from the outlet of the pressure-reducing valve  70 , and for an oxygen pressure sensor  91  to be provided in the oxygen tank body  51 . The output of these sensors is input into a control circuit. 
         [0041]      FIG. 9  shows another embodiment of the oxygen tank unit  50  according to the present invention. This embodiment shows a bayonet-type pressure-reducing valve  70 , to which the low end-wall  52 B of the tank half body  52  is installed. A plurality of bayonet claws  59  are formed on the inner peripheral portion of the large-diameter through-hole  58 B, which is formed in the low end-wall  52 B, so as to project from the inner peripheral portion of the large-diameter through-hole  58 . A cylindrical portion  71 X, which fits into the through-hole  58 B, and bayonet claws  71 Y, which are detachably connected with the bayonet claws  59 , are formed on the main housing  71  of the pressure-reducing valve  70 . The bayonet claws  59  and the bayonet claws  71 Y connect/detach by relatively rotating the cylindrical portion  71 X with the cylindrical portion  71 X inserted into the through-hole  58 B, in a manner similar to that of well known in interchangeable lenses for SLR cameras, etc. The primary pressure-introduction channel  71   a , corresponding to the primary pressure-introduction channel  71   a  of  FIG. 6 , that is communicatively connected with the through-hole  58 B is open at the cylindrical portion  71 X. The primary pressure-introduction channel and the through-hole  58 B are connected to each other in an air-tight manner via a large-diameter O-ring  79 B. The fundamental structure inside the pressure-reducing valve  70  is the same as the structure of the pressure-reducing valve  70  of  FIG. 6 . 
         [0042]    In the above embodiments, a pair of in-built check-valve cylinders (nitrogen absorption container connector-cylinders)  60  and a pressure-reducing valve  70  are both directly attached to the oxygen tank body  51 , however, a predetermined simplification in structure can be achieved even with only one thereof being directly attached to the oxygen tank body  51 . Furthermore, in the above embodiments, although the bacteria filter unit  80  is mounted onto the main housing  71  of the pressure-reducing valve  70 , an embodiment (in which the secondary pressure-outlet channel  71   b  of the pressure-reducing valve  70  is a direct air outlet) is also possible in which the bacteria filter unit  80  is omitted. 
       INDUSTRIAL APPLICABILITY 
       [0043]    The oxygen-enricher oxygen tank unit of the present invention can be widely utilized for medical purposes. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10  Oxygen enricher 
           11  Compressor 
           12   13   14   19   20   21   25   31   32   35  Conduits 
           15   16  Pressurized switching valves 
           17   18  Nitrogen absorption containers 
           22   23  Check valves 
           24  Oxygen tank 
           26  Pressure-reducing valve 
           33   34  Pressure-reducing switching valves 
           36  Exhaust muffler 
           37  Conduit 
           38   39  Throttle valves (orifices) 
           40  Purge valve 
           50  Oxygen-enricher oxygen tank unit 
           51  Oxygen tank body 
           52   53  Tank half body 
           52 A High end-wall 
           52 B Low end-wall 
           52 C Screw-bearing seats 
           54  Fixing bolts 
           55  Stepped through-holes 
           56  Small-diameter stepped portion 
           57  Large-diameter stepped portion 
           58   58 B Through-hole 
           59  Bayonet claws 
           60  In-built check-valve cylinders (nitrogen absorption container connector-cylinders) 
           62  Check valve unit 
           62   a  Valve-seat 
           62   b  Valve body 
           62   c  Valve-body holding hole 
           62   d  Through-holes 
           63  O-ring 
           64  Nitrogen absorption container connector-pipe 
           65  Mounting plate 
           65   a  Through-holes 
           66  Mounting screws 
           70  Pressure-reducing valve 
           71  Main housing 
           71   a  Primary pressure-introduction channel 
           71   b  Secondary pressure-outlet channel (oxygen outlet) 
           71   d  Screw seat 
           71 X Cylindrical portion 
           71 Y Bayonet claws 
           72  Sub-housing 
           72   a  Secondary pressure chamber 
           73  Mounting screws 
           74  Main valve 
           75  Operational diaphragm assembly 
           80  Bacteria filter unit 
           81  Lower housing 
           82  Upper housing 
           83  Bacterial filter 
           84  Gas inlet 
           85  Gas discharge outlet (oxygen outlet) 
           90  Oxygen concentration sensor 
           91  Oxygen pressure sensor