Abstract:
A gage-in-handle type pressure reducing valve wherein a feedback chamber and a pressure gage are communicated with each other through a communicating passage between a feedback member and a pressure gage guide without using a pressure introducing hole in a valve body wall or a bonnet wall, and which is capable of minimizing friction occurring in a mechanism for converting the rotation of a handle into an axial movement of a pressure regulating spring retainer. A pressure gage guide is connected to the pressure gage. The feedback member is formed with a communicating hole communicating with the feedback chamber. The communicating hole is communicated with the pressure gage guide through a communicating line. A pressure regulating nut is rotatably supported in a bonnet. The pressure regulating spring retainer is supported in the bonnet so as to be axially movable but unable to rotate. Rotation of the handle causes the pressure regulating nut to rotate, and this, in turn, causes the pressure regulating spring retainer to move axially.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a pressure reducing valve in which a secondary fluid pressure is set by actuating a cylindrical handle and a pressure gage is disposed in the handle (hereinafter referred to as “a gage-in-handle type pressure reducing valve”). 
     Japanese Utility Model Registration Application Post-Examination No. 4-45043 discloses a gage-in-handle type pressure reducing valve in which a valve chamber is disposed between a primary-side port (supply port) and a secondary-side port (output port), and a main valve element (supply valve element) in the valve chamber is urged toward a main valve seat (supply valve seat) by a valve spring (return spring). The main valve element is also urged away from the main valve seat by a pressure regulating spring fitted between a feedback member (diaphragm) and a pressure regulating spring retainer. In addition, a pressure gage is disposed in a cylindrical handle, and a feedback chamber between the feedback member and the valve chamber communicates with the pressure gage through a pressure introducing communicating passage. The axial position of the pressure regulating spring retainer is adjusted with the handle. 
     In the above-described prior art, the pressure introducing communicating passage for introducing the pressure in the feedback chamber into the pressure gage comprises pressure introducing holes in a valve body wall and a bonnet wall and a passage in a pressure regulating screw. A considerably large number of man-hours is needed to form the pressure introducing holes in the valve body wall and the bonnet wall by machining. In addition, it is necessary to provide four O-rings in order to make the passage in the pressure regulating screw air-tight. Thus, the prior art is unfavorably complicated in structure and costly. 
     SUMMARY OF THE INVENTION 
     A first object of the present invention is to provide a gage-in-handle type pressure reducing valve designed so that the feedback chamber and the pressure gage are communicated with each other through a communicating passage between a feedback member and a pressure gage guide without using a pressure introducing hole in the valve body wall or the bonnet wall. 
     A second object of the present invention is to provide a gage-in-handle type pressure reducing valve designed to minimize friction occurring in a mechanism for converting the rotation of the handle into an axial movement of the pressure regulating spring retainer. 
     To attain the above-described objects, the present invention is applied to a gage-in-handle type pressure reducing valve wherein a valve chamber is disposed between a primary-side port and a secondary-side port, and a main valve element in the valve chamber is urged toward a main valve seat by a valve spring. The main valve element is also urged away from the main valve seat by a pressure regulating spring fitted between a feedback member and a pressure regulating spring retainer. A pressure gage is disposed in a cylindrical handle, and a feedback chamber between the feedback member and the valve chamber communicates with the pressure gage through a pressure introducing communicating passage. According to a first arrangement of the present invention, a pressure regulating nut is rotatably supported in a bonnet. The pressure regulating nut has an internal thread. The pressure regulating spring retainer is supported in the bonnet so as to be axially movable but unable to rotate. The pressure regulating spring retainer has a tubular portion with an external thread. The internal thread of the pressure regulating nut is in engagement with the external thread of the tubular portion of the pressure regulating spring retainer. A pressure gage guide is connected to the pressure gage. The pressure gage guide is supported in the tubular portion of the pressure regulating spring retainer so that the pressure gage guide and the pressure regulating spring retainer are axially movable but unable to rotate relative to each other. A communicating hole is formed in the feedback member so as to communicate with the feedback chamber. The communicating hole is communicated with the pressure gage guide through a communicating line of the pressure introducing communicating passage. Rotation of the handle causes the pressure regulating nut to rotate, and this, in turn, causes the pressure regulating spring retainer to move axially. 
     According to a second arrangement of the present invention, the pressure regulating nut in the first arrangement is supported in a bearing hole provided in the bonnet. The pressure regulating nut has a flange at the lower end thereof and further has radial bolt holes in the upper end portion thereof. The pressure gage guide has an annular groove on the outer peripheral surface of the upper end portion thereof, so that the distal end portions of bolts screwed into the bolt holes of the pressure regulating nut are engaged with the annular groove of the pressure gage guide. 
     According to a third arrangement of the present invention, a hollow tube guide is slidably fitted in a sliding hole provided in the pressure gage guide in either of the first and second arrangements. The hollow tube guide has a first hollow connector. The feedback member has a second hollow connector communicating with the communicating hole. The first hollow connector and the second hollow connector are connected to each other by a flexible tube. 
     According to a fourth arrangement of the present invention, the pressure gage guide in either of the first and second arrangements has a third hollow connector, and the feedback member has a second hollow connector communicating with the communicating hole. The third hollow connector and the second hollow connector are connected to each other by a flexible coiled tube. 
     According to a fifth arrangement of the present invention, a pressure introducing part is provided between the pressure gage and the pressure gage guide in the second arrangement. The pressure introducing part has an engagement portion hermetically engaged with a large-diameter hole provided in the pressure gage guide. 
     According to a sixth arrangement of the present invention, the pressure gage guide in either of the first and second arrangements has a hollow guide portion at the distal end thereof. The feedback member has a hollow projecting portion with a sliding hole. The hollow guide portion is slidably and hermetically fitted in the sliding hole of the hollow projecting portion. 
     It should be noted that the term “communicating line” as used herein means a pipe, a pipe-shaped member, a tube, a tubular member, a hollow member, etc. having the function of providing communication, exclusive of a passage and a pressure introducing hole formed in the valve body wall or the bonnet wall. The term “a communicating line of the pressure introducing communicating passage” means that the communicating line is a part of the pressure introducing communicating passage. The third to sixth arrangements each limit the communicating line in the first arrangement. 
     According to the present invention, the feedback member is formed with a communicating hole communicating with the feedback chamber, and the communicating hole in the feedback member is communicated with the pressure gage guide through a communicating line. Therefore, the feedback chamber and the pressure gage can be communicated with each other through the communicating passage between the feedback member and the pressure gage guide without using a pressure introducing hole in the valve body wall or the bonnet wall. Accordingly, the structure is simplified, and the cost is reduced. 
     According to the present invention, further, a pressure regulating nut is rotatably supported in the bonnet, and a pressure regulating spring retainer is supported in the bonnet so as to be axially movable but unable to rotate. A pressure gage guide is connected to the pressure gage. The internal thread of the pressure regulating nut is engaged with an external thread formed on a tubular portion of the pressure regulating spring retainer. The pressure gage guide is supported in the tubular portion of the pressure regulating spring retainer so that the pressure gage guide and the pressure regulating spring retainer are axially movable but unable to rotate relative to each other. Accordingly, it is possible to minimize friction occurring in the mechanism for converting the rotation of the handle into an axial movement of the pressure regulating spring retainer. 
     Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. 
     The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a vertical sectional view showing a first embodiment of the gage-in-handle type pressure reducing valve according to the present invention. 
     FIG. 2 is a vertical sectional view showing a second embodiment of the present invention. 
     FIG. 3 is a vertical sectional view showing a third embodiment of the present invention. 
     FIG. 4 is a vertical sectional view showing a fourth embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a first embodiment of the gage-in-handle type pressure reducing valve according to the present invention. Although the terms “upper”, “lower”, “left”, “right”, etc. are used in the following description made in connection with FIG. 1, it should be noted that the directions change according to a change in installation position of the pressure reducing valve. The same shall apply to FIGS. 2 to  4 . 
     A valve body  11  made of a metal or synthetic resin material is formed with a primary-side port  12  and a secondary-side port  13 , which open on the side surfaces of the valve body  11 . A valve chamber (primary pressure chamber)  14  and a secondary pressure chamber  53  are formed between the primary-side port  12  and the secondary-side port  13 . The valve body  11  is formed with a stepped hole comprising a large-diameter hole  16  and a small-diameter hole  17 . The upper end of the large-diameter hole  16  is open. An annular flat step portion is formed between the large-diameter hole  16  and the small-diameter hole  17 . The inner surface of the small-diameter hole  17  forms the valve chamber  14  below a valve seat member  20  (described later). The valve chamber  14  communicates with the primary-side port  12 . An upward projecting portion  18  is defined between the large-diameter hole  16  and the outer surface of the valve body  11 . The valve seat member  20  has an annular projecting portion  21  and a lower flange  22  at the lower end thereof. The annular projecting portion  21  is fitted to the inner surface of the small-diameter hole  17 . The lower flange  22  is fitted to the inner surface of the large-diameter hole  16 . An O-ring is fitted in an annular groove on the outer periphery of the annular projecting portion  21  to hermetically seal the area between the outer periphery of the annular projecting portion  21  and the small-diameter hole  17 . 
     A step portion is formed on the inner surface of the annular projecting portion  21  of the valve seat member  20  (the inner surface of the annular projecting portion  21  below the step portion is larger in diameter than the inner surface above the step portion). An annular main valve seat  25  is formed on the step portion. A main valve element  26  is placed below the main valve seat  25  to face opposite thereto so that the outer peripheral portion of the upper end surface of the main valve element  26  can abut on the main valve seat  25 . The passage between the primary-side port  12  and the secondary-side port  13  is controlled by a supply valve comprising the main valve element  26  and the main valve seat  25 . A valve spring  27  is fitted between a lower step portion of the main valve element  26  and a bottom surface of the valve chamber  14 . The valve spring  27  urges the main valve element  26  toward the main valve seat  25 . A bonnet  33  made of a metal or synthetic resin material is disposed on the upper side of the valve body  11 . A small-diameter portion of the outer periphery at the lower end of the bonnet  33  is fitted into the large-diameter hole  16  of the valve body  11 . An O-ring is fitted in an annular groove on the small-diameter portion of the outer periphery at the lower end of the bonnet  33  to hermetically seal the area between the small-diameter portion of the outer periphery at the lower end of the bonnet  33  and the large-diameter hole  16 . A lower end surface  33 A of the bonnet  33  abuts on the outer peripheral portion of the upper surface of the lower flange  22  of the valve seat member  20 . A step portion  33 B at the lower end of the bonnet  33  abuts on the inner peripheral side portion of the upper surface of the upward projecting portion  18 . The bonnet  33  and the valve body  11  are connected to each other with bolts (not shown). 
     The bonnet  33  has an intermediate-diameter hole  34 , a small-diameter hole  35 , a bearing hole  36 , and a large-diameter hole  37  formed therein in that order from the lower side of the bonnet  33 . The lower end of the intermediate-diameter hole  34  and the upper end of the large-diameter hole  37  are open. A pressure regulating nut  39  is rotatably fitted into the bearing hole  36  from the lower side of the bearing hole  36 . The pressure regulating nut  39  has a flange formed at the lower end thereof. The flange prevents the pressure regulating nut  39  from coming off upwardly. A pressure regulating spring retainer  40  is disposed in the small-diameter hole  35  so as to be movable in an axial direction (i.e. the longitudinal direction of the pressure reducing valve; in the vertical direction as viewed in FIG. 1) but unable to rotate. For this purpose, for example, a flange portion  58  with a hexagonal outer surface of the pressure regulating spring retainer  40  is engaged with the small-diameter hole  35  having a hexagonal sectional configuration. It should be noted that FIG. 1 shows the pressure regulating spring retainer  40  in two different positions at the left and right sides thereof. A piston (feedback member)  42  is slidably fitted in the intermediate-diameter hole  34 . A pressure regulating spring  41  is fitted between the lower surface of the flange portion  58  of the pressure regulating spring retainer  40  and an annular groove  43  on the upper surface of the piston  42 . It should be noted that an annular groove is formed on the outer periphery of the piston  42 , and an O-ring is fitted in the annular groove to hermetically seal the area between the outer periphery of the piston  42  and the inner surface of the intermediate-diameter hole  34 . 
     An upper flange  23  of the valve seat member  20  is fitted to the lower end portion of the intermediate-diameter hole  34  in the bonnet  33 . An annular groove  24  is formed between the upper flange  23  and the lower flange  22  of the valve seat member  20 . The annular groove  24  communicates with the secondary-side port  13  through a communicating hole  29  formed in the lower flange  22 . An insertion hole  30  is formed in the center of the upper flange  23  of the valve seat member  20 . A center hole  31  (larger in diameter than the insertion hole  30 ) is formed between the insertion hole  30  and the main valve seat  25 . The inside of the center hole  31  forms the secondary pressure chamber  53 . A plurality of horizontal communicating holes  44  are formed between the upper end portion of the center hole  31  and the annular groove  24 . Feedback holes  45  are formed between the communicating holes  44  and the upper surface of the valve seat member  20 . 
     A feedback chamber  47  is formed in the intermediate-diameter hole  34  of the bonnet  33  between the piston  42  and the valve seat member  20 . A spring chamber  48  is formed above the piston  42  in the intermediate-diameter hole  34  and the small-diameter hole  35 . The spring chamber  48  communicates with the atmosphere through the bearing hole  36  and the large-diameter hole  37 . A hollow rod  51  projects from the center of the lower side of the piston  42 . The hollow rod  51  is inserted into the insertion hole  30  of the valve seat member  20  to extend through the secondary pressure chamber  53  so that the lower end (distal end) of the hollow rod  51  can abut on the flat upper surface of the main valve element  26 . The bore in the hollow rod  51  communicates with the spring chamber  48  above the piston  42  through a communicating hole  52  extending through the piston  42 . When the lower end of the hollow rod  51  (discharge valve element) is separate from the upper surface (discharge valve seat) of the main valve element  26  (i.e. when the discharge valve is open), the secondary pressure chamber  53  is communicated with the spring chamber  48  through the bore in the hollow rod  51  and the communicating hole  52  in the piston  42 . Consequently, the gas in the secondary pressure chamber  53  is discharged into the atmosphere. When the lower end of the hollow rod  51  abuts on the upper surface of the main valve element  26  (i.e. when the discharge valve is closed), communication between the secondary pressure chamber  53  and the spring chamber  48  (atmosphere) is cut off. 
     A central projecting portion is formed inside the annular groove  43  on the upper surface of the piston  42 . The upper end of the central projecting portion forms a second hollow connector  55 . The bore in the second hollow connector  55  communicates with the feedback chamber  47  through a communicating hole  56  formed in the piston  42 . A disengagement preventing portion is formed on the outer surface of the second hollow connector  55  to prevent the second hollow connector  55  from disengaging from a communicating tube  62  (described below). The second hollow connector  55  is inserted into the lower end portion of the communicating tube  62 , and the outer surface of the second hollow connector  55  is engaged with the inner surface of the lower end portion of the communicating tube  62  (an adhesive may be applied to the engaged portion). The area between the inner peripheral surface of the lower end portion of the communicating tube  62  and the outer peripheral surface of the second hollow connector  55  is hermetically sealed. It should be noted that the communicating tube  62  is made of a synthetic resin or metallic material. It is preferable to use nylon, urethane, or vinyl chloride. 
     The outer periphery of the pressure regulating nut  39  is so shaped that a portion of the pressure regulating nut  39  that is engaged with the bearing hole  36  has a circular sectional configuration and a portion of the pressure regulating nut  39  above the circular portion, which is engaged with a hexagonal center hole  83  of a handle guide  82 , has a hexagonal sectional configuration. The pressure regulating spring retainer  40  is integrally formed with a tubular portion  59  above the flange portion  58 . A lower tubular portion  60  is formed below the flange portion  58 . An internal thread is formed on the inner surface of the pressure regulating nut  39  (except the upper end portion). An external thread is formed on the outer surface of the tubular portion  59  of the pressure regulating spring retainer  40 . The internal thread of the pressure regulating nut  39  is engaged with the external thread of the pressure regulating spring retainer  40 . The pressure regulating spring retainer  40  is urged upward by the pressure regulating spring  41 . The pressure regulating nut  39 , which is in thread engagement with the pressure regulating spring retainer  40 , is also urged upward. The handle guide  82 , which has an approximately bowl-shaped configuration, is rotatably disposed in the large-diameter hole  37  of the bonnet  33 . The hexagonal center hole  83  of the handle guide  82  is engaged with the outer surface of the pressure regulating nut  39  that has a hexagonal sectional configuration. 
     A cylindrical handle  78  is rotatably fitted to the outer surface a thin-walled cylindrical portion  75  at the upper end of the bonnet  33 . The inner surface of the handle  78  is connected to the outer surface of the upper end portion of the handle guide  82  through splines. A pressure gage guide  71  is secured to the lower surface of a pressure gage  93 . An outer peripheral surface  70  of the pressure gage guide  71  is engaged with the inner surface  59 A of the tubular portion  59  of the pressure regulating spring retainer  40  so that the pressure gage guide  71  and the pressure regulating spring retainer  40  are axially movable but unable to rotate relative to each other. For example, the outer peripheral surface of the pressure gage guide  71  has a hexagonal sectional configuration, and the inner surface of the tubular portion  59  has a hexagonal sectional configuration. A plurality of radial bolt holes  84  are formed in the upper end portion of the pressure regulating nut  39 . An annular groove is formed on the outer peripheral surface of the upper end portion of the pressure gage guide  71 . The distal end portions of bolts  85  screwed into the bolt holes  84  of the pressure regulating nut  39  are engaged with the annular groove of the pressure gage guide  71 . By this engagement, the position of the pressure gage guide  71  in the axial direction (vertical direction) is locked, and the pressure gage  93  is supported by the pressure gage guide  71 . It should be noted that insertion holes  86  of the bonnet  33  and insertion holes  87  of the handle guide  82  are used when the bolts  85  are screwed into the bolt holes  84 . 
     The pressure gage guide  71  is formed with a communicating hole  72  and a sliding hole  73 . The communicating hole  72  provides communication between the sliding hole  73  and the inside of the pressure gage  93 . A hollow tube guide  64  is slidably fitted in the sliding hole  73 . An annular groove is formed on the outer periphery of the hollow tube guide  64 . An O-ring is fitted in the annular groove to hermetically seal the area between the outer peripheral surface of the hollow tube guide  64  and the sliding hole  73  of the pressure gage guide  71 . A first hollow connector  54  is formed at the lower end of the hollow tube guide  64 . A disengagement preventing portion is formed on the outer surface of the first hollow connector  54  to prevent the first hollow connector  54  from disengaging from the communicating tube  62 . The first hollow connector  54  is inserted into the upper end portion of the communicating tube  62 , and the outer surface of the first hollow connector  54  is engaged with the inner surface of the upper end portion of the communicating tube  62  (an adhesive may be applied to the engaged portion). The area between the inner peripheral surface of the upper end portion of the communicating tube  62  and the outer peripheral surface of the first hollow connector  54  is hermetically sealed. With the foregoing arrangement, the gas pressure in the feedback chamber  47  (secondary-side port  13 ) is introduced into the pressure gage  93  through the communicating hole  56  and second hollow connector  55  of the piston  42 , the communicating tube  62 , the first hollow connector  54  and communicating hole  65  of the hollow tube guide  64 , and the sliding hole  73  and communicating hole  72  of the pressure gage guide  71 . Thus, the gas pressure in the feedback chamber  47  (secondary-side port  13 ) can be measured with the pressure gage  93 . It should be noted that the bonnet  33  is fitted into a hole in a panel (not shown), and the bonnet  33  is secured to the panel by using a panel gasket  67  and a panel nut  66 . 
     In the first embodiment of the present invention, when the handle  78  is rotated, the rotational motion of the handle  78  is transmitted to the pressure regulating nut  39  through the handle guide  82 , causing the pressure regulating nut  39  to rotate. Because the internal thread of the pressure regulating nut  39  and the external thread of the tubular portion  59  of the pressure regulating spring retainer  40  are in engagement with each other, the rotational motion of the pressure regulating nut  39  is converted into an axial motion (reciprocating motion) of the pressure regulating spring retainer  40 . Thus, a pressure of the pressure reducing valve is set. In the small-diameter hole  35  of the bonnet  33 , the pressure regulating spring retainer  40  is disposed so as to be axially movable but unable to rotate. The inner surface  59 A of the tubular portion  59  of the pressure regulating spring retainer  40  and the outer peripheral surface  70  of the pressure gage guide  71  are engaged so that the pressure gage guide  71  and the pressure regulating spring retainer  40  are axially movable but unable to rotate relative to each other. The pressure gage guide  71  is secured to the pressure gage  93 . Accordingly, even when the handle  78  is rotated to cause the handle guide  82  and the pressure regulating nut  39  to rotate, the pressure gage  93  does not rotate, and the position of the scale of the pressure gage  93  does not move. Therefore, it is easy to read a numerical value indicated by the pointer of the pressure gage  93 . 
     FIG. 2 shows a second embodiment of the gage-in-handle type pressure reducing valve according to the present invention. The feature of the second embodiment resides in that the third hollow connector  54 A of the pressure gage guide  71 A and the second hollow connector  55  of the piston  42  are connected by a communicating coiled tube  62 A. No communicating tube  62  is used in this embodiment. The pressure gage guide  71 A has the third hollow connector  54 A integrally formed at the lower end thereof. The lower end of the communicating hole  72  in the pressure gage guide  71 A communicates with the bore in the third hollow connector  54 A. The rest of the arrangement and function of the second embodiment is the same as that of the first embodiment. In FIG. 2, the same members as those in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and a description thereof is omitted. 
     FIG. 3 shows a third embodiment of the gage-in-handle type pressure reducing valve according to the present invention. The third embodiment is similar to the first embodiment except that a pressure introducing part  94  is provided between the pressure gage  93  and the pressure gage guide  71 B, and an engagement portion  96  of the pressure introducing part  94  is hermetically engaged with a large-diameter hole  95  of the pressure gage guide  71 B. It should be noted that the arrangement may be such that the engagement portion  96  of the pressure introducing part  94  is formed with an external thread, and the large-diameter hole  95  of the pressure gage guide  71 B is formed with an internal thread, and further the area between the engagement portion  96  of the pressure introducing part  94  and the large-diameter hole  95  of the pressure gage guide  71 B is hermetically sealed with an O-ring or the like. The rest of the arrangement and function of the third embodiment is the same as that of the first embodiment. In FIG. 3, the same members as those in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and a description thereof is omitted. 
     FIG. 4 shows a fourth embodiment of the gage-in-handle type pressure reducing valve according to the present invention. The fourth embodiment is similar to the first embodiment except that the pressure gage guide  71 C has a hollow guide portion  74  integrally formed at the lower end thereof, and the piston  42  (feedback member) has a hollow projecting portion  89  integrally formed on the upper surface thereof, and further a sliding hole  90  is formed in the hollow projecting portion  89 . In addition, the hollow guide portion  74  of the pressure gage guide  71 C is slidably and hermetically fitted in the sliding hole  90  of the hollow projecting portion  89 . The pressure gage guide  71 C communicates with the feedback chamber  47  through the hollow guide portion  74  and the hollow projecting portion  89 . No communicating tube  62  is used in this embodiment. The rest of the arrangement and function of the fourth embodiment is the same as that of the first embodiment. In FIG. 4, the same members as those in FIG. 1 are denoted by the same reference numerals as in FIG. 1, and a description thereof is omitted.