Abstract:
Disclosed therein is a gas valve having automatically blocking means, which is mounted at an inlet side of a valve body having a ball valve so that the gas valve does not need additional blocking means for blocking a gas pipe at the time of a gas leak, and which returns a blocking member to its original position when the valve is opened after coping with the gas leak at the leaked portion, thereby making maintenance easy.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a gas valve having automatically blocking means, and more particularly, to a gas valve having automatically blocking means, which can automatically block a supply of gas according to a change in pressure at the time of a gas leak. 
         [0003]    2. Background Art 
         [0004]    In general, a gas valve is mounted in the middle of a gas pipe and serves just to control a supply of gas, and hence, gas blocking means must be mounted at the gas pipe in order to automatically block the supply of gas at the time of a gas leak. 
         [0005]      FIG. 1  shows means for blocking a supply of gas at the time of a gas leak according to a prior art. 
         [0006]    As shown in  FIG. 1 , a weight  3  is mounted inside a case  5  by means of wing portions  4  having holes so as to block an inlet  1  and an outlet  2  according to gas pressure. In a normal condition, the weight  3  is located at a position to open the inlet  1  and the outlet  2 , but when the gas pressure of the outlet side lowers due to a gas leak, the weight  3  blocks the outlet  1 . 
         [0007]    However, such an automatically blocking means for the gas valve according to the prior art has a problem in that it requires an auxiliary gas pipe  6  mounted at the outlet  2  for supplying gas and an electromagnet  7  mounted at the inlet  1  in order to return the weight  3  to its original position after coping with the gas leak. 
         [0008]    In the meantime, a method of preventing a gas leak by an electromagnetic valve operated by a sensing signal of a gas sensor has been proposed, but the preventing method has a problem in that the gas sensor cannot sense a gas microleakage or cannot sense the gas leak during the blackout. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior arts, and it is an object of the present invention to provide a gas valve having automatically blocking means, which is mounted at an inlet side of a valve body having a ball valve so that the gas valve does not need additional blocking means for blocking a gas pipe at the time of a gas leak, and which returns a blocking member to its original position when the valve is opened after coping with the gas leak at the leaked portion, thereby making maintenance easy. 
         [0010]    To achieve the above objects, the present invention provides a gas valve having automatically blocking means including: a support member having a cylindrical portion, wing portions protruding from the cylindrical portion, supporting portions intersecting at ends of the wing portions in a criss-cross form, and a through hole formed at the center of the supporting portions; a blocking member having a shaft portion inserted into the through hole, an opening and closing portion formed integrally with the shaft portion in such a way as to be restricted in position by the supporting portions, and a tip portion protruding from the center of the opening and closing portion; a spring fit onto the shaft portion in such a way as not to be separated from the shaft portion owing to a head portion formed on the shaft portion; a main body having a fixing hole into which the cylindrical portion coated with an adhesive is inserted, a passage formed to be opened and closed by the opening and closing portion, and a spiral portion formed on an outer circumferential portion thereof; a valve body having an inlet adapted to insert the main body thereinto; and a ball valve mounted in the valve body and positioned to push the tip portion of the opening and closing portion which blocks the passage when it moves to a closed position. 
         [0011]    As described above, the gas valve having the automatically blocking means according to the present invention does not need additional blocking means for blocking a gas pipe at the time of a gas leak because the automatically blocking means is mounted at the inlet side of the valve body having the ball valve. Moreover, the gas valve having the automatically blocking means returns the blocking member to its original position when the valve is opened after coping with the gas leak at the leaked portion, thereby making maintenance easy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which: 
           [0013]      FIG. 1  is a sectional view showing automatically blocking means according to a prior art; 
           [0014]      FIG. 2  is an exploded perspective view of a gas valve having automatically blocking means according to the present invention; 
           [0015]      FIG. 3  is a sectional view showing a state where gas is normally supplied in the present invention; 
           [0016]      FIG. 4  is a sectional view showing a state where a blocking member according to the present invention blocks a passage; 
           [0017]      FIG. 5  is a sectional view showing a state where the blocking member is restored; and 
           [0018]      FIG. 6  is an exemplary view showing a tool for joining a main body of the present invention to an inlet. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings. 
         [0020]    As shown in  FIG. 2 , a gas valve according to the present invention includes a support member  10 , a blocking member  20 , a spring  30 , a main body  40 , and a valve body  50 . 
         [0021]      FIG. 3  is a sectional view of the gas valve of the present invention in a state where gas is supplied normally. 
         [0022]    The support member  10  includes a cylindrical portion  11 , wing portions  12  protruding from the cylindrical portion  11 , supporting portions  13  intersecting at an end of the wing portions  12  in a criss-cross form, and a through hole  14  formed at the center of the supporting portions  13 . 
         [0023]    The blocking member  20  includes a shaft portion  21  inserted into the through hole  14 , an opening and closing portion  22  formed integrally with the shaft portion  21  in such a way as to be restricted in position by the supporting portions  13 , and a tip portion  23  protruding from the center of the opening and closing portion  22 . 
         [0024]    The blocking member  20  is joined to the support member  10  through a process of inserting the shaft portion  21  into the through hole  14 , fitting the spring  30  onto the protruding shaft portion  21  through the criss-cross portion of the supporting portion  13 , and forming a head portion  24  on the shaft portion  21 . The head portion  24  is formed by a method of riveting the end of the shaft portion  21  to expand the end of the shaft portion  21  or a method of fitting a joining hole  25  of a member  26 , which is larger in diameter than the spring  30 , onto the shaft portion  21  and bonding the member  26  to the joining hole  25  with an adhesive. In this instance, the spring  30  is joined in a state where elasticity for pushing the head portion  21  does not work. 
         [0025]    The main body  40  on which the blocking member  20  is mounted includes a fixing hole  41  to which the cylindrical portion  11  coated with the adhesive is inserted, and a passage  42  formed in front of the fixing hole  41  in such a way as to be opened and closed by the opening and closing portion  22 . 
         [0026]    It is preferable that a fine protrusion  15  is formed at a rim portion of the cylindrical portion  11  not to be stained with an adhesive when the cylindrical portion  11  is inserted into the fixing hole  41 . 
         [0027]    On an outer circumferential portion  43  of the main body  40  in which the fixing hole  41  and the passage  42  are formed, a spiral portion  44 , which is screw-coupled with a spiral hole  53  of an inlet  51 , and a cut portion  45  are formed. The cut portion  45  may be rotated in a state where a tool for joining the main body  40  to the spiral hole  53  is fit to the cut portion  45  as shown in  FIG. 6  in order to join the main body  40  to the spiral hole  53 . 
         [0028]    The valve body  50  has the inlet  51  to which the main body  40  is inserted. When the main body  40  is inserted into the inlet  51 , a ball valve  60  mounted in the valve body  50  is mounted at a position where it pushes the tip portion  23  of the opening and closing portion  22  which blocks the passage  42  while moving to a closed position so as to return the tip portion  23  to its original state. 
         [0029]    The ball valve  60  is formed in a globular shape in such a way as to be rotated by a hand-grip  62 , so that the through hole  61  is communicated with the inlet  51  and the outlet  52  or blocked from the inlet  51  and outlet  52  according to the rotated position. In other words, in the state where the through hole  61  is communicated with the inlet  51 , even though the opening and closing portion  22  blocks the passage  42 , the tip portion  23  is located at the through hole  61 . In the above state, when the hand-grip  62  is rotated, the tip portion  23  mounted close to the ball valve  60  is pushed. 
         [0030]    When the hand-grip  62  is located at a locking position, the inlet  51  and the outlet  52  are blocked by the ball valve  60 . 
         [0031]    When the hand-grip  62  is rotated to an opening position, the ball valve  60  is rotated, so that the through hole  61  is communicated with the inlet  51  and the outlet  52  and gas of the inlet  51  is supplied to the outlet  52  through a space between the supporting portions  13  and through the passage  42 . In this instance, because gas pressure acts not only on the opening and closing portion  22  but also on the outlet side, as shown in  FIG. 3 , the passage  42  is not blocked by elasticity of the spring  30 . 
         [0032]    As described above, in a state where the ball valve  60  of the valve body  50  is opened so that gas is normally used, when gas is leaked from a gas pipe  54 , pressure of the outlet  52  is suddenly decreased, and as shown in  FIG. 4 , the opening and closing portion  22  blocks the passage  42  due to the change of gas pressure. In this instance, the spring  30  is compressed, and the shaft portion  21  is supported by the through hole  14 . 
         [0033]    When the opening and closing portion  22  blocks the passage  42 , because gas supply is stopped, a user recognizes a gas leak, and hence, can take measures in a safe condition. 
         [0034]    In the state where gas supply is stopped by the blocking member  20 , when the hand-grip  62  is rotated to the closed position, a globular surface of the ball valve  60  pushes the tip portion  23  to thereby open the passage  42 , so that gas is supplied to the outlet  52  through the passage  42 , and then, the blocking member  20  moves to a position illustrated in  FIG. 5  by a restoring force of the spring  30 . 
         [0035]    That is, the gas valve according to the present invention allows the user to easily carry out a safety inspection on the blocking means because the blocking member  20  can be returned to a normal position just when the user rotates the hand-grip  62  to the closed position. 
         [0036]    In a normal condition that a difference in gas pressure between the inlet and the outlet of the valve is not large, the tip portion is located at a position spaced apart from the passage by elasticity of the spring, but when gas pressure of the outlet side is suddenly reduced due to the gas leak, the blocking member blocks the passage. As described above, the gas valve according to the present invention is easy to construct and maintain because the means for blocking gas at the time of the gas leak is mounted on the gas valve, and allows the user to conveniently and periodically carry out the safety inspection on the blocking means because the blocking member is returned to the normal condition when the user closes the valve after carrying out the measures to the gas leak. 
         [0037]    While the present invention has been particularly shown and described with reference to the preferable embodiment thereof, it will be understood by those of ordinary skill in the art that the present invention is not limited to the above embodiment and various changes may be made therein without departing from the technical idea of the present invention.