Patent Publication Number: US-10777973-B2

Title: Arrangement of stack spark gaps and device for holding together and electrically contacting stack spark gaps

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to an arrangement of stack spark gaps, whereby a stack spark gap has multiple electrodes and insulating elements that are arranged between the electrodes, with a first electrically conductive clamping element and a second electrically conductive clamping element, whereby the two clamping elements are arranged opposite to the front ends of the stack spark gaps, with at least one connecting element, by which the two clamping elements are connected to one another, and with connection elements for electrical connection of the stack spark gaps. In addition, the invention relates to a device for holding stack spark gaps together and having them make contact. 
     Description of the Related Art 
     Stack spark gaps per se have been known for many years from the state of the art, typically from the area of surge protection. Here, the stack spark gaps provide the surge diverter, which when a threshold voltage is exceeded—in equipment protection, generally a voltage above the operational voltage of a connected device but below the insulation strength with regard to surge voltages of this device—becomes conductive in fractions of a second and thus diverts the surge that is triggered. The stack spark gaps consist of multiple electrodes and multiple insulators, which are arranged between the individual electrodes, so that in each case, an insulator is located between two electrodes, which insulator has an opening in the center, so that two electrodes form a spark gap. The electrodes in most cases are designed as graphite disks; the insulators in most cases are produced as insulating films made of plastic. 
     In order to hold together the individual electrodes of a stack spark gap, it is known to clamp the electrodes and insulating elements between two clamping elements, whereby the clamping elements are connected to one another via a connecting element. 
     Moreover, it is known from the state of the art to connect to one another multiple stack spark gaps in the form of a star circuit—in the case of three stack spark gaps, also called a Y-connection. The stack spark gaps are then connected to one another, so that all stack spark gaps are interconnected in each case with a connection, namely in the star point, whereby the respective other connection of any stack spark gap uses an external connection. Then consequently, two stack spark gaps are always connected in series between two external connections. Such arrangements are used, for example, for the protection of direct voltage systems, in particular for the protection of photovoltaic units. 
     In a surge protection device that is known to the applicant from experience, the stack spark gaps are embedded in a plastic housing and are connected to one another via metal plates, which are guided crosswise by guides in the plastic housing. It is disadvantageous in the known arrangement that tensile forces that arise in the case of overvoltage have to be taken up by the housing, which results in twisting. Moreover, the number of individual electrodes of a stack spark gap is limited by the size of the recesses in the plastic housing, in which the stack spark gaps are accommodated. 
     SUMMARY OF THE INVENTION 
     The object of the invention is accordingly to provide an arrangement of stack spark gaps, in which the above-mentioned drawbacks are eliminated at least to a large extent. 
     In the case of the arrangement according to the invention, the object is achieved in that, first, three stack spark gaps are arranged beside one another between the two clamping elements. In this case, the stack spark gaps are preferably also oriented parallel to one another. In addition, the at least one connecting element is electrically conductive. As a result of both the connecting element and the clamping elements that are connected to one another by the connecting element being electrically conductive, the two clamping elements are connected to one another electrically via the connecting element. 
     Each of the stack spark gaps of the arrangement according to the invention is connected on a front end that is used as a connection side in an electrically conductive manner to one connection element in each case. Moreover, an insulator is arranged between the connection side of any stack spark gap and the clamping element that is arranged on the connection side, so that the connection side of the stack spark gap is insulated electrically from the associated, i.e., the adjacent, clamping element. The front end of any stack spark gap that is opposite to the connection side is connected in an electrically conductive manner to the clamping element that is arranged on this front end. Each stack spark gap is thus connected to a clamping element in an electrically conductive manner and is arranged electrically insulated from the other clamping element, so that altogether, the three stack spark gaps form a star circuit. In the arrangement according to the invention, the middle potential—the star point—is thus formed by the two clamping elements and the at least one connecting element. 
     The arrangement according to the invention thus combines with one another in an elegant way the mechanical attachment of the stack spark gaps and the making of electrical contact of the stack spark gaps in the form of a star circuit, namely a Y-connection. As a result of the individual stack spark gaps being arranged, in particular clamped, between two clamping elements and the two clamping elements being connected to one another by the connecting element, a flexibility is produced in a simple way in the number of electrodes and insulating elements of a stack spark gap, since the connecting element optionally can be matched to the length of the stack spark gaps. In the event of overvoltage, tensile forces that develop are taken up by the clamping elements and the connecting elements. 
     It is especially advantageous for a user when not all three connection elements of the stack spark gaps are arranged on one side of the arrangement. In particular, such an arrangement is advantageous in which two connection elements are on one side of the arrangement and one connection element is on the opposite side of the arrangement. A preferred configuration of the arrangement according to the invention is accordingly further wherein the stack spark gaps are arranged between the clamping elements in such a way that the connection sides of two stack spark gaps are facing the first clamping element, and the connection side of the third stack spark gap is facing the second clamping element. The front ends of two stack spark gaps that are opposite to the connection sides are then connected to the second clamping element in an electrically conductive manner, and the front end of the third stack spark gap that is opposite to the connection side is then connected to the first clamping element in an electrically conductive manner. Furthermore, it is especially advantageous when the two outer stack spark gaps are arranged identically. Accordingly, the center stack spark gap is preferably the third stack spark gap, which is insulated electrically from the first clamping element and which is connected to the second clamping element in an electrically conductive manner via the front end that is opposite to the connection side. In this way, the distance between the two connection elements that are arranged on one side of the arrangement can be kept as large as possible. 
     The insulators that are arranged between the connection sides of the stack spark gaps and the clamping elements can preferably be produced by respectively one separate insulator. In particular, these individual insulating plates can, for example, be made of plastic. In order to significantly reduce the installation cost, however, it is first provided—in a quite especially advantageous configuration of the arrangement according to the invention, in which two connection sides of two stack spark gaps are facing the first clamping element and a connection side of a stack spark gap is facing the second clamping element—that the two insulators are produced between the first clamping element and the stack spark gaps as a common insulating element. The arrangement according to the invention is then wherein in each case, an insulating element is arranged on the sides of the clamping elements that face the front ends, whereby a recess is formed in the first insulating element, by which recess a front end of a stack spark gap is connected to the first clamping element, and whereby two recesses are formed in the second insulating element, by which recesses the front ends of the two other stack spark gaps are connected to the second clamping element. 
     In this way, an especially simple installation of the arrangement is possible. 
     More preferably, the insulating elements are designed like a frame, whereby the outside contour of the insulating elements is matched to the outside contour of the clamping elements. Moreover, on the edges, the insulating elements preferably at least partially project beyond the clamping elements. 
     In order to contact the stack spark gaps on the front ends in an especially elegant electrically conductive manner with the clamping elements, in a preferred embodiment of the arrangement according to the invention, a contact element is arranged in each case on the front ends of the stack spark gaps that are connected to the clamping elements in an electrically conductive manner. The contact element is connected to the adjoining electrode of the stack spark gap in an electrically conductive manner. Thus, the adjoining electrode is the terminal electrode of the stack spark gap. The contact element is then also connected to the corresponding clamping element. 
     The contact is made preferably in an especially simple way via a pure pressure contact, namely in that the stack spark gaps are clamped between the clamping elements. 
     If insulating elements are provided with recesses, then the contact elements are more preferably arranged in the recesses. In particular, the contact element on the side that faces the stack spark gaps is flush with the insulating element or projects beyond the insulating element. 
     As described above, connection elements for contacting the stack spark gaps are arranged on the connection sides of the individual stack spark gaps. In one configuration, the connection elements in each case have a contact area and a connection area. Each connection element is then connected in an electrically conductive manner via its contact area to the adjoining electrode of the stack spark gap. 
     In another preferred configuration of the arrangement according to the invention, the connection area of any connection element is guided through in each case a corresponding opening in the insulator on the side of the clamping element that faces away from the stack spark gaps. In this case, the connection area or the connection element does not contact the clamping element. This can preferably be ensured in that the insulator extends into the area of the opening and in particular covers the border of the opening. In the configurations in which the insulators are produced by the insulating elements, the openings in the insulating elements are made in a corresponding manner. 
     According to the invention, the two clamping elements are connected to one another via at least one connecting element. In order to further improve the stability of the arrangement, it is provided in a preferred configuration that the two clamping elements are connected to one another via multiple connecting elements. For the way the arrangement according to the invention functions, it is sufficient for one of the connecting elements to be electrically conductive in order to connect the two clamping elements to one another electrically. It is preferable, however, when multiple, in particular all, connecting elements are electrically conductive. The connecting elements are more preferably designed as screws or as bolts. Moreover, recesses are formed in the clamping elements and/or in the insulators, through which recesses the connecting elements at least partially extend. 
     In addition to the arrangement of stack spark gaps, the invention also relates to a device for holding together and electrically contacting stack spark gaps. The device has a first electrically conductive clamping element and a second electrically conductive clamping element, between which the stack spark gaps that consist of multiple electrodes and insulators can be clamped. The two clamping elements are arranged opposite to one another in a corresponding manner. Moreover, the clamping elements are connected to one another by a connecting element. 
     According to the invention, it is now provided that the clamping elements are designed in such a way that three stack spark gaps can be positioned beside one another between the two clamping elements, and namely in such a way that the front ends of the stack spark gaps point to the clamping elements. The stack spark gaps can preferably be positioned parallel to one another between the clamping elements. The connecting element, with which the clamping elements are connected to one another, is electrically conductive. Since the clamping elements are also electrically conductive, this results in that the two clamping elements are connected to one another in an electrically conductive manner via the connecting element. 
     Two insulators are also arranged on the first clamping element of the device according to the invention. The insulators are arranged on the clamping element in such a way that two of the stack spark gaps can be arranged with a front end against the first clamping element in an insulating manner. An insulator is arranged on the second clamping element. As a result, the third stack spark gap can be arranged with a front end against the second clamping element in an insulating manner. 
     The device according to the invention is thus designed in such a way that three stack spark gaps, on the one hand, are held together and, moreover, can be held arranged beside one another in an elegant manner, and, on the other hand, are contacted in a special way. One stack spark gap is contacted via the first clamping element; two stack spark gaps are contacted via the second clamping element. Since, moreover, the two clamping elements are connected to one another electrically, the device according to the invention opens up an elegant possibility of connecting stack spark gaps to one another in a star circuit. To this end, the device itself forms the middle potential. 
     An especially advantageous configuration of the device according to the invention is distinguished in such a way that the two insulators that are arranged on the first clamping element are produced by a common first insulating element. The insulator that is arranged on the second clamping element is produced by a second insulating element. In this way, the installation cost is reduced, since fewer parts have to be installed, when two insulators are produced by a single insulating element. 
     Especially advantageously, the insulators or insulating elements are designed as previously described in connection with the arrangement according to the invention. All statements made in connection with the arrangement as well as all configurations of the insulators and insulating elements apply with all described features in a corresponding manner for the device for holding stack spark gaps together and having them make contact according to the invention. 
     The features that relate to the configurations of the connecting element and the clamping element and have been implemented in connection with the arrangement according to the invention also apply in a corresponding manner for the device according to the invention. 
     In another configuration, a contact element for contacting a stack spark gap is arranged on the first clamping element, and two contact elements for contacting two stack spark gaps are arranged on the second clamping element. If the insulating elements according to the invention with the corresponding recesses are arranged on the clamping elements, then the contact elements are configured and arranged on the clamping elements in such a way that they are arranged in the recesses of the insulating element. The outside contours of the contact elements are especially preferably matched to the outside contours of the recesses. 
     In general, there are a large number of possibilities for further developing and configuring the arrangement of stack spark gaps according to the invention and the device for holding stack spark gaps together and having them make contact. To this end, reference is made the description of preferred embodiments in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an arrangement of stack spark gaps, 
         FIG. 2  is a perspective view of a first configuration of a device for holding stack spark gaps together and having them make contact, 
         FIG. 3  is a perspective view of a second configuration of a device for holding stack spark gaps together and having them make contact, 
         FIG. 4 a    is a perspective view of a first clamping element, 
         FIG. 4 b    is a perspective view of a second clamping element, 
         FIG. 5  is a perspective view of three stack spark gaps, 
         FIG. 6  is a perspective view of parts of the arrangement of stack spark gaps, and 
         FIG. 7  is a perspective view of the parts, depicted in  FIG. 6 , of the arrangement with three electrodes. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a sectional view through an arrangement  1  of stack spark gaps  2 . The arrangement  1  comprises three stack spark gaps  2 , whereby each stack spark gap  2  is built up of multiple electrodes  3  and insulating elements  4  that are arranged between the electrodes  3 . The stack spark gaps  2  are clamped between a first clamping element  5  and a second clamping element  6 . Moreover, the stack spark gaps  2  are arranged beside one another in a parallel manner. The two clamping elements  5 ,  6  are arranged opposite to one another on the ends  7  ( FIG. 5 ) of the stack spark gaps  2  and are also connected to one another via connecting elements  8 . In the perspective view, two connecting elements  8  are visible. The clamping elements  5 ,  6  and the connecting elements  8  are electrically conductive, in such a way that the two clamping elements  5 ,  6  are connected to one another electrically via the connecting elements  8 . 
     Each stack spark gap  2  can be connected via a connection element  9 , whereby the whereby the connection elements  9  are arranged on the ends of the stack spark gaps  2  that are used as connection sides  10  ( FIG. 5 ). 
     The arrangement  1  is designed overall in such a way that an insulator  11  is arranged between the connection sides  10  of the stack spark gaps  2  and the clamping element  5 ,  6  that is arranged on the respective connection side  10 . As a result, the connection sides  10  of the stack spark gaps are insulated electrically from the corresponding clamping elements  5 ,  6 . 
     The front end  7 , i.e., the end opposite to the end on the connection side  10  at which the respective connection element  9  is connected, of any stack spark gap  2  is connected in an electrically conductive manner to the clamping element  5 ,  6  that is arranged on the front end  7 . Each individual stack spark gap  2  is thus connected to a clamping element  5 ,  6  in an electrically conductive manner and is arranged, moreover, opposite to the other clamping element  5 ,  6  in an insulating manner. By this configuration, it is achieved that the stack spark gaps  2  form a star circuit. The clamping elements  5 ,  6  and the connecting elements  8  in this case form the middle potential. 
     The two outer stack spark gaps  2  face the first clamping element  5  with their connection sides  10  and accordingly connect to the second clamping element  6  in an electrically conductive manner. The center stack spark gap  2  faces the second clamping element  6  with its connection side  10  and accordingly connects to the first clamping element  5  in an electrically conductive manner. A preferred arrangement of the connection elements  9  is thus produced, since two connection elements  9  lie on one side of the arrangement  1 , and a connection element  9  lies in the center on the other side of the arrangement  1 . 
     Altogether, it is achieved by the arrangement  1  that there are always two stack spark gaps  2  between two connection elements  9  and thus two conductors, to which the arrangement  1  is connected via the connection elements  9 . In the case where the stack spark gaps  2  are conductive, the following current path is thus produced: 
     Via the connection element  9 , through a stack spark gap  2 , through the clamping element  5 ,  6 , with which the stack spark gap  2  is connected in an electrically conductive manner, via the connecting element  8 , via the opposite clamping element  5 ,  6 , through the stack spark gap  9  that is connected with this clamping element  5 ,  6  in an electrically conductive manner to the connection element  9  that is arranged on this stack spark gap. 
       FIG. 2  shows the first electrically conductive clamping element  5  and the second electrically conductive clamping element  6 , which are connected to one another via four electrically conductive connecting elements  8  and form the middle potential of the arrangement  1 . The connecting elements  8  are produced as screws and are guided from the exterior of the second clamping element  6  through recesses  12  in the clamping elements  5 ,  6  on the exterior of the first clamping element  5 . The screw heads  13  thus lie on the exterior of the second clamping element  6 , while the screws are attached by screw nuts  14  to the exterior of the first clamping element  5 . By using multiple connecting elements  8 , the stability of the arrangement  1  is increased. As is evident in  FIG. 2 , moreover, heads  13  are made on the clamping elements  5 ,  6 . 
       FIG. 3  shows a configuration in which the insulators  11 , with which the connection sides  10  of the stack spark gaps  2  are electrically insulated relative to the clamping elements  5 ,  6 , are made by insulating elements  16 ,  17 . A first insulating element  16  is arranged on the side of the first clamping element  5  that faces the front ends  7  of the stack spark gaps  2 . The insulating element  16  completely coats the clamping element  5  with the exception of a recess  18  that is formed in the center in the insulating element  16 . Because of the recess  18 , the front end  7  of the stack spark gaps  2  that are arranged in the center can be connected to the clamping element  5  in an electrically conductive manner, while the connection sides  10  of the two outer stack spark gaps  2  are insulated electrically from the clamping element  5  by the insulating element  16 . A second insulating element  17  is arranged on the side of the second clamping element  6  that faces the front ends  7  of the stack spark gaps  2 . The insulating element  17  has two recesses  18 , which are formed in the insulating element  17  in such a way that the front ends  7  of the two outer stack spark gaps  2  can be connected in an electrically conductive manner to the second clamping element  6  through the recesses  18 . The recesses  18  can be seen in  FIG. 1 . 
     The insulating elements  16 ,  17  have the shape of a frame. The outside contour  19  of the insulating elements  16 ,  17  is matched to the outside contour  20  of the clamping elements  5 ,  6 . Altogether, the insulating elements  16 ,  17  are designed in such a way, however, that they project on the edges somewhat beyond the clamping elements  5 ,  6 , so that a reliable insulation is ensured. 
       FIG. 4 a    shows the first clamping element  5 ;  FIG. 4 b    shows the second clamping element  6 . A contact element  21  is arranged on the first clamping element  5 . In the assembled state, the contact element  21  is arranged between the front end  7  of the center stack spark gap  2  and the first clamping element  5 . The contact element  21  is connected in an electrically conductive manner to the adjoining electrode  3  of the stack spark gap  2 . Two contact elements  21  are arranged on the second clamping element  6 , which contact elements are connected in an electrically conductive manner in the assembled state to the adjoining electrodes  3  of the outer stack spark gaps  2 . The contact elements  21  are also depicted in  FIGS. 1 and 3 . 
     The three stack spark gaps  2 , which are arranged beside one another in a parallel manner, are shown in  FIG. 5 . In the illustrated embodiment, each stack spark gap  2  has twelve electrodes  3 . The contact elements  21  are arranged on the front ends  7 , which make electrical contact with the clamping elements  5 ,  6 . The connection elements  9  are arranged on the connection sides  10 . The connection elements  9  have a contact area  22  and a connection area  23 . The contact areas  22  of the connection elements  9  are connected to the adjoining electrodes  3  in an electrically conductive manner. The connection of the stack spark gaps  2  to the corresponding lines is done via the connection areas  23 . The contact areas  22  of the connection elements  9  are designed flat in order to form as large a contact surface as possible with the electrodes  3 . 
     The connection areas  23  of the connection elements  9 , however, are made angular. Because of the angular design of the connection areas  23 , the connection areas  23  can be guided in an elegant way through openings  24  that are made in the insulators  11 ,  16 ,  17  on the side of the clamping elements  5 ,  6  that faces away from the front ends  7 . This is depicted especially clearly in  FIG. 6 , which shows the second clamping element  6  with the second insulating element  17 . Two openings  24  are made in the insulating element  17 , through which openings the connection areas  23  of the connection elements  9  are guided onto the side of the clamping element  6  that is applied to the front ends  7  of the stack spark gaps  2 . In this case, the connection element  9  does not touch the clamping element  6 . In order to ensure this, the insulating element  17  extends through the opening  24 , as evident in  FIG. 1 . In the insulating element  17 , the recess  18 , in which the contact element  21  is arranged, is formed in the center. Moreover, recesses  12  for creating the connecting elements  8  are also formed in the insulating element  17 . 
     Besides the elements that are depicted in  FIG. 6 ,  FIG. 7 , in addition in each case shows an electrode  3  of a stack spark gap  2 , i.e., altogether three electrodes, which are arranged beside one another. The two outer electrodes  3  are in this case contacted via the contact area  22  of the connection elements  9  and are electrically insulated against the clamping element  6  by the insulating element  17 . The center electrode  3  makes electrical contact with the clamping element  6  via the contact element  21 .