Abstract:
The present invention discloses a pressure regulator comprising: a housing having an inlet opening for the supply of pressurized fluid under primary pressure from a pressurized fluid source and an outlet opening for discharging the pressurized fluid under a secondary reduced pressure, a channel between the aforementioned inlet opening and outlet opening; and a pressure-regulating mechanism for reducing the aforementioned primary pressure to the aforementioned secondary pressure. The pressure regulator&#39;s pressure-regulating mechanism has a movable body that comprises a diaphragm which is displaceable in response to pressure fluctuations, the inlet opening and the movable body being in line with each other in the direction substantially perpendicular to the direction of the diaphragm displacement. The present invention is reduces the dimensions while extending the service life of a pressure regulator intended for decrease of fluid pressure even when the pressure regulator operates with fluids such as high-pressure gas with corrosive properties.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a pressure regulator for reducing pressure of a pressurized fluid such as gas, liquid, or the like, from a primary pressure to a secondary pressure through a pressure regulating mechanism. 
         [0003]    2. Description of the Related Art 
         [0004]    Known in the art are pressure regulators, which are used as devices for reducing pressure of fluids, such as liquids, gases, etc., stored under pressure in fluid-supply sources, to a predetermined level and for supplying the reduced-pressure fluids to external devices. 
         [0005]    The aforementioned known pressure regulators are used, e.g., as high-pressure gas regulators employed in liquefied gas utilization apparatuses, gas supply equipment, or similar gas-handling devices (see Patent References 1 and 2). 
         [0006]    These apparatuses reduce high primary pressure at which the gas is supplied and provide a permanent outlet pressure (secondary pressure). A pressure regulator of the aforementioned type normally has a diaphragm displaceable in response to fluctuations of gas pressure, a pressure control chamber separated by the diaphragm [into two parts], and a pressure control valve located in the aforementioned pressure control chamber and connected to the diaphragm so that the inflow of gas is controlled by opening or closing the valve seat in the gas supply channel. 
         [0007]    Another pressure regulator for fluids is one known as a water-pressure governor (Non-Patent Reference 1). This governor has a construction essentially similar to the gas-pressure regulator. 
         [0008]    On the other hand, subjects of recent investigation and miniaturization are pressure regulators for supply of fuel from stable-pressure fuel supply sources used in connection with notebook computers, personal data-assistants, or similar small electronic devices, especially portable telephones that incorporate power sources in the form of fuel cells. 
         [0000]    [Patent Reference 1] Unexamined Patent Application Publication [hereinafter referred to as “Kokai”] 2004-318683 
       [Patent Reference 2] Kokai 2004-334755 
     [Non-Patent Reference 1] Toshi Gasu Kogyo [City Gas Industry], Utensil Compilation, Japan Gas Association, S56.5.10, p. 236 
       [0009]    However, in a pressure regulator of the type described, e.g., in Patent Reference 2, the connection opening (the inlet opening) of the gas inlet unit which is to be connected to the fluid-supply source has its central axis oriented in the diaphragm-displacement direction. This increases the size of the pressure regulator in the displacement direction and makes it difficult to incorporate this regulator into a flat device such as a portable telephone. 
         [0010]    The pressure regulators disclosed in the aforementioned Non-Patent Reference 1 and in Patent Reference 1 have gas or liquid inlet openings (i.e., the openings for connection to the fluid supply source) which are arranged perpendicular to the direction of diaphragm displacement. However, since the diaphragm and the fluid inlet opening are located in separate positions in the aforementioned displacement direction, this, similar to the previous example, increases dimensions of the regulator in the diaphragm displacement direction and makes it difficult to incorporate this regulator into a flat device such as a portable telephone. 
         [0011]    Based on the above information, it is an object of the present invention to provide pressure regulator that has small dimensions and a flat shape. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    A pressure regulator of the invention comprises: a housing having an inlet opening for the supply of a pressurized fluid under a primary pressure and an outlet opening for discharging the pressurized fluid under a secondary reduced pressure, and a channel between the aforementioned inlet opening and outlet opening, the fluid being supplied from a fluid-supply source; and a pressure regulating mechanism for reducing the aforementioned primary pressure to the aforementioned secondary pressure; the pressure regulator being characterized by the fact that the pressure regulating mechanism has a moveable body that comprise a diaphragm which is displaceable in response to pressure fluctuations, the inlet opening an the moveable body being in line with each other and oriented in the direction substantially perpendicular to the direction of the diaphragm displacement. 
         [0013]    The housing of the aforementioned pressure regulator comprises:
       a main casing the interior of which contains the aforementioned moveable body with the diaphragm, the outer peripheral portion of the diaphragm being sandwiched from one side [of the housing] and from a second side [of the housing] that is opposite to the first side, and a pressure-control chamber that contains the aforementioned channel on said first side;   a cover casing that is located on said second side and contains an atmospheric-pressure chamber connected with the atmosphere; and   a cylindrical connector that contains the aforementioned inlet opening, is connected to the main casing, and has its central axis oriented substantially perpendicular to the diaphragm displacement direction.       
 
         [0017]    The aforementioned main pressure-control chamber used in the pressure regulator of the invention is provided with a partition that divides this chamber into a primary-pressure chamber connected to the inlet opening and a secondary-pressure chamber that is connected to the outlet opening;
       the aforementioned partition being arranged substantially perpendicular to the diaphragm displacement direction and being provided with a communication opening for connecting the primary-pressure chamber with the secondary-pressure chamber; the moveable body consisting of two parts between which the diaphragm is sandwiched, both parts moving together with the diaphragm, one of this parts being located on the main-casing side of the diaphragm and another on the cover-casing side of the diaphragm;   among the aforementioned two parts, the one which is located on the main-casing side projecting outside the main casing and being provided with an axial extension through which said communication opening passes;   an annular groove being formed in the periphery on the tip of the axial extension, and a pressure-control valve that opens and closes the aforementioned communication opening being placed into the aforementioned annular groove.       
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a general three-dimensional view of a pressure regulator made according one embodiment of the invention. 
           [0022]      FIG. 2  is a sectional view along line II-II of  FIG. 1 . 
           [0023]      FIG. 3  is an exploded three-dimensional view of a part of the pressure regulator. 
           [0024]      FIG. 4  is a three-dimensional sectional view of the pressure regulator. 
           [0025]      FIG. 5  is a sectional view illustrating connection of the pressure regulator of  FIG. 1  to a pressurized-fluid container. 
       
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Effects of the Invention 
       [0026]    Since in the pressure regulator of the invention, the pressure regulation mechanism has a moveable body that contains a diaphragm displaceable in response to fluctuation of fluid pressure and since the inlet opening and the moveable body are lined with each other in the direction perpendicular to the displacement direction of the diaphragm, it is not necessary to arrange the input opening in the same direction as the displacement of the diaphragm. Therefore, the pressure regulator can be flattened in the aforementioned displacement direction. 
       DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0027]    A pressure regulator of the present invention will be further explained in more details with reference to one practical embodiment.  FIG. 1  is a three-dimensional view of a pressure regulator according to one embodiment of the invention, and  FIG. 2  is a sectional view along line II-II of  FIG. 1 . For convenience of the description of the illustrated embodiment, the part of the device shown on the side of the cover case will be referred to as the upper part, and the side of the main case will be referred to as the lower part. 
         [0028]    In general, the pressure regulator  1  comprises a housing  2  that contains the following components: a fluid inlet opening  21  for receiving a pressured fluid under primary pressure from a fluid-supply source (not shown in the drawings) such as, e.g., a fuel container for a fuel cell; an outlet opening  22  for discharging the pressurized fluid under a secondary pressure which is lower than the primary pressure; a channel  23  that extends from the inlet opening  21  to the outlet opening  22 ; and a pressure regulating mechanism  3  for reducing the pressure from primary to secondary installed in the aforementioned channel  23 . 
         [0029]    The housing  2  consists of a main casing  4  having an inner space (that forms the aforementioned channel  23 ), a cover casing  5 , and a cylindrical connector  6  attached in the transverse direction to the side of the main casing  4 . The main casing  4  and cover casing  5  are attached to each other, e.g. by screws and are in contact with the upper surface  8   a  and the lower surface  8   b , respectively, of the peripheral portion of a diaphragm  8  (that is described below) which is sandwiched between the aforementioned cover casing  5  and the main casing  4 . Furthermore, respective spaces are formed between the cover casing  5  and the diaphragm  8  and between the main casing  4  and the diaphragm  8 , of which the space  50  on the cover-casing side is connected to the atmosphere, while the space on the main-casing side comprises a pressure control chamber  40  that contains the aforementioned channel  23 . 
         [0030]    A downward directed projection  51  (a stopper) is formed on the inner wall and in the central part of the cover casing  5 . The lower end face of this projection  51  is made flat. A small-diameter opening  51   a  that is formed in the tip, i.e., in the lower end face of the projection  51  connects the chamber  50  with the atmosphere so that this chamber is maintained under the atmospheric pressure. 
         [0031]    The diaphragm  8  is placed onto the main casing  4  (which is described below), is held in place by a shoulder  4   a  formed on the entire periphery of the upper surface of the main casing  4 , and is fixed and clamped from both sides between the aforementioned first (lower) surface  8   b  that faces the pressure control chamber  40  and the aforementioned second (upper) surface  8   a  that faces the atmospheric-pressure chamber  50 . Thus, the lower surface  8   b  of the diaphragm is under an increased pressure of the fluid while the upper surface  8   a  of the diaphragm experiences the atmospheric pressure so that under the effect of the pressure difference between the fluid pressure and the atmospheric pressure the diaphragm can deflect in the vertical direction. However, the diaphragm is maintained in a balanced position since the urging force generated by the aforementioned pressure difference is counterbalanced by the resilient force of a pressure-control spring  11 , which is described below. 
         [0032]    The diaphragm  8  can be made, e.g., from rubber or a similar material that may have a flat form and possesses resiliency. The diaphragm has a round opening pierced in the center thereof and a curvilinear circular projection  82  at a certain distance from the center of the diaphragm. Furthermore, the diaphragm  8  has a support  9  (which is described later) located on the upper side, i.e., on the side of the atmospheric-pressure chamber  50 ), and a shaft unit  10  (which is described later) located on the lower side, i.e., on the side of the pressure-control chamber  40 . Both the support  9  and the shaft unit  10  are made integrally with the diaphragm  8  and move together therewith in the vertical (axial) direction in response to resilient displacements of the diaphragm  8 . Altogether, the diaphragm  8 , support  9 , and shaft unit  10  form a moveable body  7 . The axis that passes essentially through the center of the moveable body  7  is axis Y in the direction of which the moveable body  7  moves. 
         [0033]    The support  9  consists of a flat essentially disk-like portion  91  that is rigidly attached to the upper side of the diaphragm and extends inward from the curvilinear circular projection  92  and an essentially cylindrical projection portion  92  that projects upward from the central part of the disk-like portion  91 . The circular projection  92  is located opposite to the projection  51  of the cover casing  5  and, similar to the projection  51 , has a flat upper end face and a male thread  93  cut from the upper to the lower end of the projection  51 . The support  9  can be preferably made from a light-weight material such as polyoxymethylene (POM) but it can also be made from metal. 
         [0034]    A compression coil spring  11  (hereinafter referred to as “a pressure control spring”) is placed onto the outer surfaces of the circular projection  92  of the support  9  and the projection  51 . Normally, the pressure-control spring  11  urges the diaphragm  8  downward with a predetermined force through the support  9 . Under normal operation conditions of the pressure regulator of the invention a gap G exists between the lower end face of the projection  51  and the upper end face of the projection  92  of the support  9 . When the pressure of the supplied pressurized fluid becomes excessive, the axial extension  103  of the shaft unit  10  (which is described later) is urged upward, the upper end face of the support projection  92  is pressed against the lower end face of the projection  51  of the cover casing  5 , and as a result, excessive deformation of the diaphragm is prevented. 
         [0035]    The shaft unit  10  has a substantially cylindrical large-diameter portion  101 , which is rigidly connected to the lower (first) surface of the diaphragm  8 , and upper and lower axial extensions  102  and  103 , respectively, that extend in the vertical direction from the central part of the cylindrical large-diameter portion  101 . The axial extension  103  passes through an opening  43   a  of the main casing  4  so that its lower end projects from the aforementioned opening. An annular groove  103   a  is formed in the periphery of the projecting tip of the axial extension  103 , and a pressure-control valve  12  for opening and closing the opening  43   a  is secured in the annular groove  103   a . The pressure-control valve  12  may comprise a resilient seal ring. Even if the volume of the pressure-control valve  12  of this construction has increased because of swelling caused by contact with pressurized liquid such as oil, such volumetric deformation will not affect closing/opening operation of the valve or flow rate of the fluid since displacements of the press-control valve in the vertical direction will be limited by the annular groove  103   a.    
         [0036]    The axial extension  102  passes through an opening  81  of the diaphragm  8  and extends to the upper end face of the projection  92 . A male thread  102   a  formed on the axial extension  102  is threaded into a female thread  93  formed in the support  9  so that the diaphragm appeared to be secured from both sides and is clamped between the support  9  and the shaft unit  10  for forming an integral body therewith. It is preferable to place between the support  9  and the diaphragm  8  a film made from a material with low coefficient of friction, e.g., from polyethylene terephthalate (PET). Provision of this film makes it possible to reduce deformation of the diaphragm  8  under the effect of a friction force that occurs when the diaphragm  8  is secured in place by screwing the support  9  onto the axial projection  102 . 
         [0037]    The main casing  4  also has a partition  43  that divides the pressure-control chamber  40  into a secondary pressure-control chamber  42  that faces the diaphragm  8  and a primary pressure-control chamber  41  that is located below the secondary pressure-control chamber  42 . 
         [0038]    In the position corresponding to the aforementioned axial projection  103  of the shaft unit  10 , the partition  43  has a through opening  43   a  between the primary pressure-control chamber  41  and the secondary pressure-control chamber  42 .  FIG. 4  is a sectional three-dimensional view of the pressure regulator  1  shown in  FIG. 1 . As can be seen from  FIG. 4 , the device has a fluid-passing groove  42   a , which is formed on the side of the secondary pressure-control chamber  42  of the main casing  4 . This groove extends from the through opening  43   a  and is also connected to the aforementioned cylindrical connector  6 . Thus, if pressure in the primary pressure-control chamber  41  drops, the aforementioned moveable body  7  moves down, and the lower end face  101  of the large-diameter part  101  of the shaft unit  10  comes into contact with the surface on the side of the secondary pressure-control chamber  42  of the main casing  4 , whereby it becomes possible to facilitate the flow of the pressurized liquid admitted from the primary pressure-control chamber  41 . 
         [0039]    Extended downward from the lower surface of the partition  43  is a first annular projection  44  that surrounds the tip of the aforementioned axial extension. The annular projection is surrounded from the outside by a cover member  45 . In order to bring the upper surface of the cover member  45  into contact with the lower surface of the main casing  4  and the bottom wall of the cover into contact with the lower end face of the annular projection  44 , the cover member  45  may be removably connected to the annular projection  44 , e.g., by forming a thread in its inner wall for screwing it onto the annular projection  44 . Thus, the aforementioned primary pressure-control chamber  41  is defined by the inner surface of the cover member  45  and the inner surface of the first annular projection  44 . 
         [0040]    Fluid-passing channels  44   a  and  44   b  for the supply of pressurized fluid into the primary pressure-control chamber  41  from an inlet fluid flow channel  47   a  through an opening  47   b  are formed in the outer peripheral surface and the lower end face of the first annular projection  44 , respectively. In the position opposite to the point where the axial extension  103  is fixed, the fluid-passing channel  44   a  formed in the outer peripheral surface extends from the lower end face of the first annular projection  44  in the upward direction and further passes through the opening  47   b  on the side of the inlet fluid flow channel  47   a  and then extends to the upper end of the inlet fluid flow channel  47   a . The fluid passing channel  44   b  formed in the lower end face extends from the channel  44   a , which is formed in the outer peripheral surface, and enters the primary pressure-control chamber  41 . 
         [0041]    In the illustrated embodiment, the main casing  4  is shown as having one groove  44   a  and one groove  44   b  formed on the outer peripheral surface and on the lower end face of the first annular projection  44 , respectively, on the side opposite to fixation of the axial extension  103 . However, the invention is not limited to such an arrangement. For example, only the inlet fluid flow channel  47   a  can be used if this channel is connected to the primary pressure-control chamber  41 . 
         [0042]    When in response to displacement of the diaphragm  8  the axial extension  103  shifts upward or downward (in the direction of axis Y), the aforementioned pressure-control valve  12  (seal ring) located in the primary pressure-control chamber  41  comes into contact or is separated from the lower end face of the partition  43 , whereby fluid can either flow or not flow through the gap formed between the axial extension  103  and the through-opening  43   a . In this way it becomes possible to control pressure of fluid in the secondary pressure-control chamber  42 . The aforementioned pressure-control mechanism  3  is formed from the pressure-control spring  11 , moveable body  7 , pressure-control valve  12 , etc, 
         [0043]    One end of the main casing  4  is connected to the secondary pressure-control chamber  42  which contains pressurized fluid under secondary, i.e., reduced, pressure provided by the aforementioned pressure-control mechanism  3 , while the other end of the aforementioned main casing  4  can be connected, e.g., to a fuel cell (not shown in the drawing). The main casing  4  also contains a nozzle  46  with a discharge opening  22  for discharging fluid pressurized under secondary pressure from the interior of the secondary pressure-control chamber  42 . The central axis X 1  of the nozzle  46  is arranged substantially perpendicular to axis Y. 
         [0044]    In the illustrated embodiment, the nozzle  46  is connected to the side of the main casing  4 , but the invention is not limited to such an arrangement, and other modifications are possible for connection to a fuel cell, or the like, provided that one end of the nozzle is connected to the secondary pressure-control chamber. For example, the nozzle can project in the downward direction or can extend at an angle. 
         [0045]    Furthermore, the main casing  4  has a second annular projection  47  that contains the aforementioned flow-inlet channel  47   a  which receives the primary-pressure fluid from the cylindrical connector  6 , which is described later. The second annular projection  47  is an integral part of the main casing  4  and has its central axis X 2  oriented in the direction substantially perpendicular to axis Y. One end of the fluid inlet channel  47   a  on the side of the moveable body  7  is connected to the fluid-passing channel  44   a , which is formed on the outer periphery of the first annular extension  44 . The fluid-passing opening  47   b  is formed at the lower end and inside the fluid-passing opening  47   a  in order to connect the aforementioned fluid-passing channel  44   a  with the fluid inlet opening  47   a.    
         [0046]    Furthermore, an annular groove  47   c  is formed on the outer periphery at the base of the second annular projection  47  to accommodate a seal ring  48  of the aforementioned cylindrical connector  6 . A thread, which is not shown in the drawing, can be made on the outer peripheral surface of the second annular projection  47  for threaded connection of the cylindrical connector  6  [to an external device.—Tr. Note] 
         [0047]    The cylindrical connector  6  is an element for connection to a fluid-supply source such as a pressurized fluid container, which is described below. The cylindrical connector  6  has a partition  6   a  arranged substantially in the middle of its length. The partition  6   a  receives the lower axle  64   c  of a plug  64 , which is described later, and is provided with an inlet opening  21  for receiving the primary-pressure fluid from the fluid-supply source. Installed in a space between the partition  6   a  and the second annular extension  47  are the following components, which are listed in the direction away from the secondary annular extension  47 : a filter  61 , a joint  62 , a compression spring  63  (hereinafter referred to as “spring  63 ”), and the plug  64 . 
         [0048]      FIG. 3  is an exploded three-dimensional view of parts located on the rear side of the aforementioned secondary annular extension  47 . For convenience of subsequent explanation of the cylindrical connector  6 , the upper side of  FIG. 3  corresponds to the right side of  FIG. 2 , and the lower side of  FIG. 3  corresponds to the left side of  FIG. 2 . 
         [0049]    The joint  62  can be molded, e.g., from polyoxymethylene, and comprises a substantially cylindrical body having an upper wall  62   a . The upper wall  62   a  has a cylindrical opening  62   b , and a flange  62   d  that extends radially outward is formed between the upper wall  62   a  and the lower end face  62   c.    
         [0050]    The filter  61  comprises a disk and a disk-like member  61   a  from which a cylindrical wall  61   b  extends in the downward direction. The filter  61  fits onto the upper wall  62   a  of the joint  62 . In the assembled state of the device, the flange  62   d  of the joint  62  contacts the lower end face of the second annular extension  47  of the main casing  4 , and the filter  61  is sandwiched between the upper wall  62   a  of the joint  62  and an intermediate shoulder  47   d  of the second annular extension  47 . The upper end of the filter  61  is connected to the fluid inlet channel  47   a , which communicates with the first pressure-control chamber  41 . This filter protects the pressure-regulating mechanism  3  from penetration of small particles of dirt, etc., that may be contained in the primary-pressure fluid. This prevents malfunction of the working parts of the pressure-regulating mechanism. The inner peripheral surface of the joint  62  has a plurality of mutually spaced vertical grooves  62   e . These grooves form channels for passing the primary-pressure fluid. 
         [0051]    The plug  64  comprises a pin made from stainless steel or molded from polyoxymethylene. A disk-like flange  64   a  is formed near the upper end of the plug  64 . An upper extension  64   b  formed above the flange  64   a  should have a diameter suitable for insertion into the helical spring  63 , and a lower extension  64   c , which is located below the flange  64   a , tapers downward, converging to the tip. The aforementioned lower extension  64   c  has a seal ring  64  in the vicinity of the flange  64   a.    
         [0052]    In the assembled state of the cylindrical connector  6  and the secondary annular extension  47 , the spring  63  and plug  64  are held between the upper wall  62   a  of the joint  62  and the partition  6   a  of the cylindrical connector  6 . As a result, the flange  64   a  of the plug  64  is urged downward by the helical spring  63 , and the seal ring  65  is compressed between the flange  64   a  and the partition  6   a . When the cylindrical connector  6  is not connected to the fluid-supply source, the seal ring  65  is urged by the spring  63  and thus maintains the partition  6   a  and the flange  64   a  in tight contact. This prevents leakage of the pressurized fluid contained in the fluid-supply source through the gap between the lower extension  64   c  of the plug  64  and the inlet opening  21  of the partition  6   a.    
         [0053]    The above-described connector  6  is attached to the main casing  4 . 
         [0054]    A specific feature of the present invention is that the inlet opening  21  and the above-described moveable body  7  are aligned with respect to each other in the direction of movement of the moveable body, i.e., in the direction substantially perpendicular to axis Y. In other words, the central axis X 3  of the inlet opening  21  and the cylindrical connector  6  are also perpendicular to axis Y, and the moveable body can be positioned at any point on the central axis X 3 . This means that in a pressure regulator as such, the cylindrical connector  6  or the inlet opening  21  need not be located below the moveable body and, therefore, no connecting parts are needed below the cover  45  of the main casing  4 , and the device as a whole can be made narrower in the direction of movement of the moveable body (i.e., vertical direction). 
         [0055]    The central axis X 3  of the cylindrical connector  6  and the inlet opening  21  are not necessarily coaxial with the central axis X 2  of the aforementioned fluid inlet channel  47   a , and it is preferable that the central axis X 3  of the cylindrical connector  6  and the inlet opening  21  be slightly higher above the central axis X 2  of the fluid inlet channel  47   a . This will reduce the possibility for the outer extension of the cylindrical connector  6  to be displaced below the cover  45  of the main casing  4 . 
         [0056]    However, the pressure regulator of the present invention is not limited by the structure in which the outer extension of the cylindrical connector  6  does not go beyond the position of the cover  45  of the main casing  4 , i.e., when the size of the regulator is reduced in the direction of movement of the moveable body (i.e., in the direction of axis Y). For example, the principle of the invention will not be violated in a modification where the central axis X 3  of the cylindrical connector  6  and of the inlet opening  21  is coaxial with the central axis X 2  of the aforementioned fluid inlet channel  47   a  or where the central axis X 3  of the cylindrical connector  6  and of the inlet opening  21  is located below the central axis X 2  of the aforementioned fluid inlet channel  47   a.    
         [0057]    Since the internal parts of the pressure regulator of the present invention are kept in contact with fluid over a long time, they must be made from materials that are resistant to solvents; in particular, they may be coated with a layer of a polyparaxylylene-type resin, especially Parylene N (the trademark of Nippon Parylene Company). It is especially preferable to apply a protective coating made from rubber. Since such a protective coating prevents direct contact of fluid with the surface of the rubber parts, it becomes possible to reduce the cost of the parts of the pressure regulator of the invention by using materials such as NBR, IR, or the like, which are less expensive than conventionally used rubber materials such as EPDM. 
         [0058]    In order to improve sliding properties, it is recommended to apply the aforementioned coatings also on the outer surface of the seal ring  48  which is fitted onto the outer surface at the base of the second annular extension  47 . 
         [0059]      FIG. 5 , which is a partial sectional view of the pressure regulator  1 , illustrates the pressure regulator  1  of the present invention in a position when it is connected to a pressurized fluid container  200  such as a fuel cartridge of a fuel cell. In  FIG. 5 , only a part of the pressurized fluid container is shown as a section. The pressurized fluid container  200  comprises a tubular pipe union  201  and a main body  202  attached to the pipe union  201 . The pipe union  201  has a vertical through-opening  203 . This opening contains a valve body  205  that is urged upward by a spring  204  to prevent ejection of fluid from the pressurized fluid container  200 . The valve body is installed in the opening  203 . 
         [0060]    As shown in  FIG. 4 , when the pressurized fluid container  200  is attached to the pressure regulator  1 , the valve body  205  shifts the plug  64  upward. As a result, the inlet opening  21  of the cylindrical connector  6 , which is sealed by the seal ring  65 , opens, and the primary-pressure fluid begins to flow sequentially through the inlet opening  21 , the grooves  62   e  in the inner wall of the joint  62 , and the filter  61 . Since in the initial stage of connection of the pressurized fluid container  200  pressure of the fluid in the secondary pressure-control chamber  42  is low, the diaphragm  8  is urged downward by the pressure-adjusting spring  11 . Therefore, the pressure-control valve  12  that seals the through-opening  43   a  of the main casing  4  moves down from the through-opening  43   a  in the separation direction. The valve  12  separates from the lower surface of the partition  43  and assumes the open position. As a result, the primary-pressure fluid flows through the aforementioned channels, filter  61 , first pressure-control chamber  41 , the gap between the opening  43  and the axial extension  103 , second pressure-control chamber  42 , and nozzle  46 , and is discharged through opening  22  to the outside, e.g., to a fuel cell, which is not shown in the drawings. 
         [0061]    The following is a more detailed description of the pressure-control mechanism  3 . 
         [0062]    In a normal state, the diaphragm  8  is adjusted by the pressure-control spring  11  so that in response to the fluid supplied at a pressure, e.g., in the range of 900 KPa to 1 MPa, the diaphragm  8  maintains a predetermined pressure in the secondary-pressure chamber. More specifically, when the primary pressure of the fluid supplied from the pressurized-fluid container  200  exceeds the allowable secondary pressure, the fluid contained in the secondary-pressure chamber  42  overcomes resistance of the pressure-control spring  11  and urges the diaphragm  8  in the upward direction. As a result, the axial extension  103  of the shaft unit  10  will move upward, and the pressure-control valve will close the communication opening  43   a  of the main casing  4  so that supply of the pressurized fluid into secondary-pressure chamber  42  will be discontinued. On the contrary, if pressure of the fluid in the secondary-pressure chamber  42  drops, the axial extension will be shifted down by the force of the pressure-control spring  11 , the communication opening  43   a  will be opened, and admission of the pressurized fluid to the secondary-pressure chamber  42  will be resumed. Thus, by moving up and down in response to fluctuations of fluid pressure, the diaphragm  8  will maintain the secondary pressure at a constant level. 
         [0063]    The detailed description given above relates only to an embodiment of the invention. However, when the pressurized fluid container  200  is connected to the pressure regulator  1  of the invention, a securing device of some kind is needed for securing the container  200  to the regulator  1 . Such a device may comprise a resilient clamping mechanism (not shown) capable of holding both parts together by means of a helical spring or a leaf spring. For example, this may be a fixing mechanism disclosed in the Japanese Patent Application 2004-266463 of the same applicant, or any other mechanism the structure of which is beyond the scope of the present patent application. 
       LEGEND 
       [0000]    
       
           1  Pressure regulator 
           2  Housing 
           21  Fluid inlet opening 
           22  Outlet opening 
           23  Channel 
           3  Pressure-control mechanism 
           4  Main casing 
           40  Pressure-control chamber 
           41  Primary-pressure chamber 
           42  Secondary-pressure chamber 
           43  Partition 
           43   a  Communication opening 
           44  First annular projection 
           44   a ,  44   b  Fluid-passing channels 
           45  Cover 
           46  Nozzle 
           47  Second annular projection 
           47   a  Inlet fluid flow channel 
           47   b  Communication opening 
           47   c  Groove 
           47   d  Intermediate shoulder 
           48  Inlet flow seal ring 
           5  Cover casing 
           50  Atmospheric pressure chamber 
           6  Cylindrical connector 
           6   a  Partition 
           61  Filter 
           62  Joint 
           63  Spring 
           64  Plug 
           65  Seal ring 
           7  Moveable body 
           8  Diaphragm 
           9  Support 
           10  Shaft 
           103  Axial extension 
           103   a  Annular groove 
           11  Pressure-control spring 
           12  Pressure-control valve 
         G Gap