Abstract:
An apparatus which is constituted to supply electrical energy to a melting and vaporizing material (for example metal wire  6 ) so as to cause the melting and vaporizing material to melt and vaporize, thereby demolishing an object to be demolished (such as concrete  2 ) using the vaporization and expansion force generated at the time of melting and vaporization of the material; wherein either by providing a granular material 8 which ejects from a container following the generation of the vaporization and expansion force, or by using an inflammable material as demolishing material 46 in which the melting and vaporizing material is immersed, a to-be-demolished object is demolished with a strong demolishing force.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a demolishing apparatus using discharge impulse for demolishing an object to be demolished, such as concrete or rock mass, by using discharge energy. 
     BACKGROUND ART 
     So far, dynamite has been known as demolishing means for demolishing an object to be demolished such as concrete or rock mass, however, a danger is involved in handling the dynamite. 
     A demolishing apparatus using discharge impulse, which uses discharge energy, has been proposed in recent years as a way of eliminating such danger. 
     This demolishing apparatus using discharge impulse comprises a pair of electrodes connected to each other by means of a metal wire, and an energy supply circuit being connected to these electrodes and adapted to supply electrical energy to the metal wire, wherein the metal wire is immersed in a demolishing material (a liquid such as water or a semisolid material is used) filled in a demolishing container (hereinafter referred to simply as “container”). 
     Next, the demolishing method for the aforementioned demolishing apparatus using discharge impulse will be explained. According to the method, the metal wire is immersed in the container filled with a demolishing material, the demolishing container is installed in an installation hole formed in an object to be demolished, the supply circuit is connected to the electrodes, a capacitor installed in this supply circuit is charged with a prescribed quantity of electrical energy, and this electrical energy is supplied to the metal wire for a short time (for example, several dozen μs), that is in other words, electric power is discharged. Whereupon, the metal wire suddenly melts and vaporizes and expands in volume. Following this, the demolishing material also suddenly vaporizes and expands. The volume expansion force of the metal wire is transmitted by this demolishing material, and the sudden volume expansion force of the metal wire and the vaporization and expansion force of the demolishing material act on the walls of the installation hole, for example, in such a manner that the installation hole is pressed outward, thereby demolishing the object to be demolished. 
     However, with the aforementioned demolishing apparatus, the vaporization and expansion force of the demolishing material filled in the container is used to demolish an object to be demolished, so that resultant physical force such as a shock force cannot be sufficient. Therefore, there are such cases, depending on the kind of object to be demolished, that sufficient demolishing force cannot be obtained, and because of this, further improvement of the demolishing force is desired. 
     It is an object of the present invention to provide a demolishing apparatus using discharge impulse which is capable of resolving the foregoing problems. 
     DISCLOSURE OF THE INVENTION 
     The present invention is a demolishing apparatus using discharge impulse in which electrical energy is supplied for a short time to a melting and vaporizing material (for example, a metal wire is used) placed in a container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein a container is filled with a demolishing material which vaporizes and expands following the melting and vaporizing of the melting and vaporizing material, and a granular material (metal balls, pebbles, ceramic balls or the like are used) which transmits a direct force to the surroundings by a volume expansion force generated when the melting and vaporizing material melts and vaporizes. 
     According to this invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the volume expansion force generated during the melting and vaporization of the melting and vaporizing material causes the granular material to give a shock to the object to be demolished, thereby demolishing the object without fail. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a container so as to cause the melting and vaporizing material to suddenly vaporize and melt, thereby demolishing an object to be demolished; wherein the container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes and a direct shock force; wherein a synthetic resin or paper, or a metal pipe, is used as a material constituting the container; and wherein a cylindrical holding body made of a hard material and having an opening at least at one end thereof is provided in the container such that the container faces the object to be demolished. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is ejected from the opening at one end of the cylindrical holding body toward the object to be demolished by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes; and wherein the cylindrical container is made of a hard material and includes a soft stopper element provided at an opening at one end of the cylindrical container. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is caused to break the stopper element from the opening at one end of the cylindrical holding body so as to be ejected toward the object to be demolished, by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings a volume expansion force generated when the melting and vaporizing material melts and vaporizes, said cylindrical container being made of a hard material; wherein a soft stopper element for holding the demolishing material and granular material is provided at a portion partway toward an opening formed at one end of the cylindrical container; and wherein a space portion is formed between the stopper element and the one end of the cylindrical container. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material is caused to break the stopper element to eject itself from the opening at one end of the cylindrical holding body toward the object to be demolished, by the volume expansion force generated during the melting and vaporization of the melting and vaporizing material, thereby demolishing the object to be demolished reliably with the strong demolishing force. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the cylindrical container is filled with a demolishing material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, and a granular material which transmits to the surroundings the force of volume expansion generated when the melting and vaporizing material melts and vaporizes, said cylindrical container being made of a hard material; wherein a soft stopper element for holding the demolishing material and granular material is provided at a portion partway toward an opening formed at one end of the cylindrical container; wherein a space portion is formed between the stopper element and the one end of the cylindrical container; and wherein a portion of the cylindrical container corresponding to the space portion formed between the stopper element and the one end is formed in a conical shape such that the inner diameter of the portion on the opening side is greater than the inner diameter on the stopper element side. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes as the electrical energy is supplied to the melting and vaporizing material; the demolishing material vaporizes and expands following the melting and vaporizing of the melting and vaporizing material; the volume expansion force of the melting and vaporizing material is transmitted to the object to be demolished; and the granular material destroys the stopper element and is ejected, but in a limited ejection range, from the opening at one end of the cylindrical holding body toward the object to be demolished, by the volume expansion force generated during the melting and vaporizing of the melting and vaporizing material, thereby demolishing the object to be demolished reliably by the strong demolishing force. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the container is filled with an inflammable demolishing material which burns and vaporizes following the melting and vaporization of the melting and vaporizing material. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes and expands in volume when electrical energy is supplied to the melting and vaporizing material; following this, the inflammable demolishing material burns and vaporizes; and the burning and vaporizing force of the demolishing material acts, with a time lag, on cracks caused by the volume expansion force of the melting and vaporizing material, thereby reliably demolishing the object to be demolished in such a manner as to expand the cracks outward. 
     Also, the present invention is a demolishing apparatus using discharge impulse which is constituted to supply electrical energy for a short time to a melting and vaporizing material placed in a cylindrical container so as to cause the melting and vaporizing material to suddenly melt and vaporize, thereby demolishing an object to be demolished; wherein the container is filled with an inflammable demolishing material which burns and vaporizes following the melting and vaporization of the melting and vaporizing material, and a stable material which vaporizes and expands following the melting and vaporization of the melting and vaporizing material, in such a condition that the inflammable demolishing material and the stable material are separated from each other; and wherein the melting and vaporizing material is immersed in both the inflammable demolishing material and the stable demolishing material. 
     According to this constitution of the invention, the melting and vaporizing material melts and vaporizes and expands in volume when electrical energy is supplied to the melting and vaporizing material; following this, the stable demolishing material vaporizes and expands and causes cracks in the object to be demolished; with a slight time delay from the volume expansion of the melting and vaporizing material and from the vaporization and expansion of the stable demolishing material, the inflammable demolishing material burns and vaporizes; and the burning and vaporizing force of the demolishing material acts on the cracks, thereby reliably demolishing the object to be demolished in such a manner as to expand the cracks outward. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the first embodiment of the present invention; 
     FIG. 2 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the second embodiment of the present invention; 
     FIG. 3 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the third embodiment of the present invention; 
     FIG. 4 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the fourth embodiment of the present invention; 
     FIG. 5 is a cross section showing the constitution of a demolishing apparatus using discharge impulse according to the fifth embodiment of the present invention; 
     FIG. 6 is a cross section showing the installed state of the demolishing apparatus using discharge impulse in an object to be demolished according to the fifth embodiment of the present invention; 
     FIG. 7 is a cross section showing the installed state of a demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention; 
     FIG. 8 is a plan view showing the installed state before demolition of the demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention; 
     FIG. 9 is a plan view showing the state during demolition of the demolishing apparatus using discharge impulse in an object to be demolished according to the sixth embodiment of the present invention; 
     FIG. 10 is a plan view showing the completed state of demolition of the object to be demolished for the demolishing apparatus using discharge impulse showing the sixth embodiment of the present invention; 
     FIG. 11 is a graph showing the relationship between the passage of time and expansion force in the demolishing apparatus using discharge impulse according to the sixth embodiment of the present invention; and 
     FIG. 12 is a cross section showing the constitution of a demolishing apparatus using discharge impulse according to the seventh embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is explained in more detail with reference to the appended figures. 
     The first embodiment for implementing the present invention is explained on the basis of FIG. 1. A demolishing apparatus using discharge impulse  1  in this first embodiment comprises: a bottomed cylindrical or pouch-shaped demolishing container (hereinafter, simply referred to as “container”)  4  inserted in an installation hole  3  formed in an object to be demolished  2 ; a pair of electrodes (or conductive wires)  5  inserted in this container  4 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum)  6  connecting the end portions of these electrodes (or conductive wires)  5 ; a demolishing material  7  and a granular material  8  filled in this container  4 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of said pair of electrodes  5  by means of electrical wiring  9 . 
     The electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged into the capacitor to the metal wire  6  so as to effect discharge. Also the container  4  is formed of a soft material such as synthetic resin or an elastic material such as rubber. Furthermore, used as the demolishing material  7  is a solid or semisolid material, for example, and to be more specific, it is mortar, mud, silicone, or gel. Used as the granular material  8  is metal balls, pebbles, or ceramic hard balls, for example. 
     In the case of demolishing an object to be demolished, or concrete  2  for example, using said demolishing apparatus using discharge impulse  1 , an installation hole  3  is formed in a to-be-demolished portion of said concrete  2 , then the container  4 , which has the metal wire  6  inserted thereinto, the demolishing material  7  and the granular material  8  filled therein, and a cover element  10  affixed to an opening at the upper end thereof, is inserted into the installation hole  3 . Next, the electrical energy supplying device is connected through the electrical wiring  9 . 
     Then a discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire  6  for a short time. Whereupon the metal wire  6  suddenly melts and vaporizes. Following this, the demolishing material  7  also vaporizes and transmits the volume expansion force of the metal wire  6  to the concrete  2 , such that the volume expansion force, in combination with the vaporization and expansion force of the demolishing material  7 , forms a demolishing force and demolishes the concrete  2 . 
     Since the granular material  8 , such as metal balls, is mixed in the demolishing material  7 , the granular material  8  also flies apart into the surroundings with extremely strong force caused by the volume expansion force of the metal wire  6 , whereby the concrete  2  is demolished reliably. 
     In this way, since a lot of granular material  8  is mixed in the demolishing material  7 , the volume expansion force of the metal wire  6  can be efficiently transmitted to the surroundings. 
     Next, the second embodiment for implementing the present invention is explained on the basis of FIG.  2 . The demolishing apparatus using discharge impulse  12  in this second embodiment comprises: a cylindrical container  13  having an opening at both upper and lower ends; a stopper element  14  affixed to the opening at the lower end of the cylindrical container  13 ; a pair of electrodes  15  inserted in the cylindrical container  13 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum)  16  connecting the end portions of the electrodes  15 ; a demolishing material  17  and a granular material  18  for filling the cylindrical container  13 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of the pair of electrodes  15  through electrical wiring  19 . 
     The electrical energy supplying device comprises: a charger, such as a capacitor, which accumulates high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrodes  15  so as to effect discharge. 
     Also, the cylindrical container  13  is formed of a hard material such as metal, and the stopper element  14  is formed of a soft material such as thin resin film (wrapping film) used for storing food, vinyl, paper, rubber, thin metal plate or the like. In other words, the stopper element  14  is provided simply to prevent the granular material  18  filled in the cylindrical container  13  from escaping to the outside, and can easily be broken when the volume of the metal wire  16  expands. If the demolishing material  17  is in the solid form such as a gel, the stopper element  14  need not be installed. 
     Further, like in the first embodiment, a solid or semisolid material, for example, is used as the demolishing material  17 . To be more specific, it is mortar, mud, silicone, or gel. And, metal balls, pebbles, or ceramic balls, for example, are used as the granular material  18 . 
     In order to demolish an object to be demolished, for example concrete  20 , by using the foregoing demolishing apparatus using discharge impulse  12 , a cylindrical container  13  which has a stopper element  14  attached to the opening at the lower end thereof, a metal wire  16  placed therein, a demolishing material  17  and a granular material  18  both filled therein, and a cover element  21  affixed to the opening at the upper end thereof, is placed on a to-be-demolished portion of the concrete  20 . Then, an electrical energy supplying device is connected through electrical wiring  19 . 
     Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire  16  in a short time. Whereupon the metal wire  16  suddenly melts and vaporizes. Following this, the demolishing material  17  also vaporizes and transmits the volume expansion force of the metal wire  16  to the concrete  20 , said volume expansion force combining with the vaporization and expansion force of the demolishing material  17  to form a demolishing force, thereby demolishing the concrete  20 . 
     Since the granular material  8 , such as metal balls, is mixed in the demolishing material  7 , the granular material  8  also flies apart into the surroundings with extremely strong force due to the volume expansion force of the metal wire  6 , whereby the concrete  2  is demolished reliably. 
     Also the granular material  18  mixed in the cylindrical container  13  is filled to a height of half that of the demolishing material  17 , for example. Because the granular material  18  is positioned on the side toward the opening in the lower end in the cylindrical container  13 , the portion above the granular material  18  functions as a pressure producing portion with only the metal wire  16  placed in the demolishing material  17 . 
     Consequently, during the melting and vaporization of the metal wire  16 , the granular material  18 , positioned on the side toward the opening in the lower end in the container  13 , breaks through the stopper element  14  from the cylindrical container  13  like a shotgun shell and is discharged all at once toward the concrete  20 , whereby the demolishing force is concentrated by the granular material  18  and the concrete  20  is demolished reliably. 
     Next, the third embodiment for implementing the present invention is explained on the basis of FIG.  3 . This demolishing apparatus using discharge impulse  23  in this third embodiment has about the same constitution as the above mentioned second embodiment. The same symbols are applied to the same elements and a detailed explanation thereof is omitted. 
     In other words, as shown in FIG. 3, an extension portion  13   a  is formed which extends straight just from the cylindrical container  13  below a stopper element  14  provided at the lower end of the cylindrical container  13  in the second embodiment. 
     With this constitution, when an object to be demolished, such as concrete  20 , is about to be demolished, the opening on the lower end of the extension portion  13   a  of the cylindrical container  13  having the metal wire  16 , demolishing material  17 , and granular material  18  placed therein, is held in the state of being pressed against a to-be-demolished portion of the concrete  20 , and electrical energy is supplied to the metal wire  16 , whereby the demolishing material  17  and granular material  18  together are ejected toward the concrete  20 , with the volume expansion force of the metal wire  16 , thereby demolishing the concrete  2 . At this time, the straight extension portion  13   a  of the cylindrical container  13  plays the role of a barrel and guides a large number of granules of the granular material  18  in the same direction, thereby increasing the demolishing force to be even stronger. 
     Next, the fourth embodiment for implementing the present invention is explained on the basis of FIG.  4 . In the demolishing apparatus using discharge impulse  23  in the above mentioned third embodiment, the downward extension portion  13 a of the cylindrical container  13  was straight in form. However, in the demolishing apparatus using discharge impulse  25  according the fourth embodiment, the extension portion is formed in a conical shape such that the inner diameter of the opening on the lower end of the cylindrical container  13  is greater than the inner diameter of the portion where the stopper element  14  is provided. 
     In addition to the effects obtained from the demolishing apparatus using discharge impulse  23  according to the third embodiment, this constitution allows it to control the volume expansion force of the metal wire  16  and the range of ejection of the granular material  18 , which become the demolishing force during the melting and vaporization of the metal wire  16 . 
     Next, the fifth embodiment for implementing the present invention is explained on the basis of FIGS. 5 and 6. The demolishing apparatus using discharge impulse  27  according to the fifth embodiment comprises: a cylindrical or pouch-shaped demolishing container (hereinafter referred to simply as “container”)  28  having a bottom; a pair of electrodes (or conductive wires)  29  inserted in the container  28 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum)  30  connecting the end portions of the electrodes  29 ; a demolishing material  31  and granular material  32  filling the container  28 ; a cylindrical holding body  34  which holds the container  28  being filled with the electrodes  29 , demolishing material  31  and granular material  32  and having a cover element  33  fixed in the opening at the upper end thereof, and which has an opening at both upper and lower ends thereof; a cover body  35  screwed onto the opening at the upper end of the cylindrical holding body  34 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy in a short time to the base portions of the pair of electrodes  29  through electrical wiring  36 . Moreover, a hole portion  35   a  is formed in the cover body  35  so as to allow passage of the electrodes  29 . 
     The electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply electrical energy charged in the capacitor to the pair of electrodes  29  so as to effect discharge. 
     The container  28  is formed of an elastic material such as rubber or a soft material such as synthetic resin. Further, a solid or semisolid material, for example, is used as the demolishing material  31 , more specifically, it is mortar, mud, silicone or gel, and metal balls, pebbles or ceramic balls, for example, are used as the granular material  32 . 
     When an object to be demolished, such as concrete  37 , is demolished using the foregoing demolishing apparatus using discharge impulse  27 , the cover element  33  is fixed in the opening portion at the upper end of the container  28  filled with the metal wire  30 , demolishing material  31  and granular material  32 , as shown in FIG. 5, and subsequently, as shown in FIG. 6, the container  28  is inserted in the cylindrical holding body  34  in such a manner as to face the concrete  37  by being held by a ring-shaped protruding portion (the protruding portion may simply consists of a plurality of protrusions provided at a plurality of locations)  34   a  protruding at a prescribed location inside the cylindrical holding body  34 . Thereafter the cover body  35  is screwed onto the opening at the upper end to hold the entire container  28 . 
     The cylindrical holding body  34  holding the container  28  is placed to be pressed against a to-be-demolished portion of the concrete  37 . As electrical energy is supplied to the metal wire  30  in this state, powerful demolition can be effected in the same way as in the third embodiment. 
     Next, the sixth embodiment for implementing the present invention is explained on the basis of FIGS. 7 through 11. The demolishing apparatus using discharge impulse  40  in this sixth embodiment comprises: a cylindrical or pouch-shaped container  43  having a bottom and being inserted in an installation hole  42  formed in an object to be demolished  41 ; a pair of electrical wires (electrodes)  44  inserted in this container  43 ; a metal wire (an example as a melting and vaporizing material, such as copper, iron or aluminum)  45  connecting the end portions of the electrical wires  44 ; a demolishing material  46  filling the container  43 ; a cover element  47  to seal this demolishing material  46 ; and an electrical energy supplying device (not depicted) to supply high voltage electrical energy for a short time to the base portions of the pair of electrical wires  44  through electrical wiring  48 . 
     The foregoing metal wire  45  is immersed in the demolishing material  46 , said demolishing material  46  being composed of an inflammable material such as thinner or kerosene, or an explosive material. 
     The foregoing electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrical wires  44  so as to effect discharge. 
     When an object to be demolished, such as a concrete  41 , is demolished using the foregoing demolishing apparatus using discharge impulse  40 , the container  43  is filled with the demolishing material  46 , the demolishing material  46  is sealed with the cover element  47  which the electrical wires  44  pass through, the container  43  is inserted in the installation hole  42  formed in the concrete, the installation hole  42  is filled with tamping material  50  such as sand, and the electrical energy supplying device is connected to the metal wire  45  through the electrical wiring  48 . 
     Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire  45  for a short time. Whereupon the metal wire  45  suddenly melts and vaporizes. Following this, the demolishing material  46  also burns and vaporizes (explodes) together and transmits the volume expansion force of the metal wire  45  to the concrete  41 , said volume expansion force combining with the vaporization and expansion force of the demolishing material  47  to form a demolishing force, thereby demolishing the concrete  20 . 
     Here is an explanation of the sequence in which the concrete  41  is demolished. With the volume expansion force generated during the melting and vaporization of the metal wire  45 , a plurality of cracks  51  occur around the installation hole  42  as shown in FIG.  9 . Subsequently, after a passage of a small period of time t, the demolishing material  46  burns and vaporizes, and the force of vaporization and expansion thereof acts on the cracks  51  and expands these cracks  51  outward, as shown in FIG. 10, thereby destroying the concrete  41 . 
     FIG. 11 is a graph in which the horizontal axis represents the passage of time since the supply of electrical energy and the vertical axis the vaporization and expansion force of the metal wire at the time of volume expansion thereof. The solid line A shows the case where the metal wire  45  suddenly melts and vaporizes, and the broken line B shows how the vaporization and expansion force produced when the demolishing material  46  burns and vaporizes acts on each crack  51 . It is known from this graph that the vaporization and expansion force of the demolishing material  46  acts gradually on each crack  51  in the object to be demolished  41 . 
     In the above mentioned sixth embodiment, an inflammable material or explosive material is used as the demolishing material  46  to be filled in the container  43 . As a result, the vaporization and expansion force of the demolishing material  46  acts gradually on the plurality of cracks  51  caused to occur by the volume expansion force of the metal wire  45 , and the cracks  51  are expanded outward, whereby the concrete  41  is demolished reliably. 
     Next, the seventh embodiment for implementing the present invention is explained on the basis of FIG.  12 . In the demolishing apparatus using discharge impulse  55  according to the seventh embodiment, the demolishing material  56  comprises a stable material  57  in the form of a gel and an inflammable material  58  in the form Qf a liquid, said stable material  57  and inflammable material  58  being separated in the container  50 , and a metal wire  60  is immersed in both of the stable material  57  and the inflammable material  58 . 
     A cover element  61  to seal the demolishing material  56  is installed on the container  62 , and an electrical energy supplying device (not depicted) for supplying high voltage electrical energy for a short time to the metal wire  60  is connected to the base portions of a pair of electrical wires (electrodes)  63 . Also, the metal wire  60  is made to expose itself by removing part of a covering element  64  of the electrical wires  63  partway. 
     The foregoing electrical energy supplying device comprises: a charger, such as a capacitor, to accumulate high voltage electrical energy; a charging circuit to charge this capacitor; and a discharge circuit to supply the electrical energy charged in the capacitor to the pair of electrical wires  63  so as to effect discharge. 
     When an object to be demolished is demolished using the foregoing demolishing apparatus using discharge impulse  40 , the container  62  is filled with the demolishing material  56 , the demolishing material  56  is sealed with the cover element  61  which the electrical wires  63  pass through, the container  62  is inserted in the installation hole formed in the object to be demolished, the installation hole is filled with a tamping material such as sand, and the electrical energy supplying device is connected to the metal wire  60  through the electrical wiring  63 . 
     Then the discharge switch installed on the discharge circuit is turned on and electrical energy (discharge energy) is supplied to the metal wire  60  for a short time. Whereupon the metal wire  60  suddenly melts and vaporizes. Following this, the stable material  57  vaporizes and the inflammable material  58  also burns and vaporizes, thereby transmitting the volume expansion force of the metal wire  60  to the object to be demolished, and the volume expansion force of the metal wire  60  combines with the vaporization and expansion force of the demolishing material  56  so as to form a demolishing force to the effect of demolishing the object to be demolished. 
     Here is an explanation of the sequence in which the object to be demolished is demolished. With the volume expansion force generated during the melting and vaporization of the metal wire  60 , the stable material  57  vaporizes and the volume expansion force of the metal wire  60  is transmitted, and a plurality of cracks occur around the installation hole. Subsequently, after a passage of a small period of time t, the inflammable material  58  also burns and vaporizes, and the vaporization and expansion force thereof acts on the cracks to expand these cracks outward, thereby demolishing the object to be demolished reliably. 
     INDUSTRIAL APPLICABILITY 
     As discussed above, the demolishing apparatus using discharge impulse relating to the present invention can be advantageously used in the case of demolishing an object to be demolished that requires a great demolishing force.