Abstract:
The disclosure relates to a process valve for a media flow path, particularly for use in the beverage industry or pharmaceutical, chemical and food industry, including at least one valve disk, at least one primary seal lying on the valve disk, at least one secondary seal, and at least one hollow space bounded by at least one primary seal and at least one secondary seal having at least one conically tapered groove for holding the secondary seal. The secondary seal is incorporated in such a manner that it seals on only one side and is permeable to media that flow out of the hollow space.

Description:
FIELD OF THE INVENTION 
     The invention relates to a process valve of the type specified in the introductory portion of Patent Claim  1 . 
     BACKGROUND 
     At present, hollow spaces in process valves, said hollow spaces bordering on seals, particularly as the process valves are used in media flow paths in the food/beverage filling industry, but also in the pharmaceutical and chemical industry, are hermetically sealed, which means that in the case of a proper seal, media flows, such as e.g., product or food flows, do not penetrate into the process valve, nor do any media present in the aforementioned hollow spaces escape out of the process valve and penetrate into the surroundings or into the media flow paths conducted by the process valve. 
     Among other reasons, one reason for the presence of hollow spaces in process valves, such as, e.g., gaps, that border on seals, is, e.g., the fact that valve disks are often multi-piece and e.g., gaps or hollow spaces can form between valve disk parts that are screwed together. One reason for this multi-piece construction of valve disks is constituted by the fact that this simplifies, e.g., the assembly of ring seals into the retaining groove of the valve disk because the ring seal has to be less strongly deformed during the integration into the retaining groove. Other reasons for the hollow spaces in the valve disk can be due to screwed connections, e.g., of valve disk to valve stem or other process valve components, that are installed for maintenance reasons. 
     As mentioned, as a rule, the described hollow spaces in process valves are sealed hermetically by sealing elements that seal on both sides. 
     Described in DE102010003445A1 is, e.g., a process valve as a seat valve having an internal screwed connection of valve parts that seals the interior of the seat valve, particularly the area between the disk parts that borders on the seal, hermetically to the outside. 
     DE102010030300A1 (see particularly FIG. 1) describes a process valve as a double seat valve having a multi-piece upper valve disk and a multi-piece lower valve disk in which any hollow spaces or gaps that exist between the screwed-together valve disk parts and that border on seals are sealed on both sides with respect to the inside and outside. 
     Detrimental in the known process valves is, among others factors, that when there are temperature changes, unwanted pressures can form within hermetically chambered hollow spaces that border on the process valve primary seal, which can damage the process valve primary seal or interfere with the function of the same. Moreover, the detection of leakages in the event of a defective primary seal or leaks in the fixing points of the primary seal is hindered. 
     An object of the present disclosure is consequently to improve process valves, particularly process valves for use in the beverage filling industry, particularly with respect to the sealing behaviour and maintainability. 
     SUMMARY 
     In some arrangements, this object is achieved according to the present disclosure by means of a process valve in accordance with Claim  1 . 
     Advantageous embodiments and further developments are the subject of the dependent claims. 
     In some arrangements, a process valve according to the disclosure in a media flow path, particularly for use in the beverage filling industry, can thereby contain at least one valve disk, at least one primary seal lying on the valve disk, at least one secondary seal, at least one hollow space bounded by at least one primary seal and at least one secondary seal and having at least one conically tapered groove for holding a secondary seal, and it can be distinguished by the fact that the secondary seal is incorporated in such a manner that it seals on only one side and is permeable to media that flow out of the hollow space. 
     In other words, the described secondary seal is consequently distinguished by the fact that the secondary seal can seal against media that flow against the secondary seal in the tapering direction of the conically tapered groove, while the secondary seal can allow media through that flow against the secondary seal in the direction of the broadening direction of the conically tapered groove. 
     The secondary seal can thereby be provided in such a manner that it can be leaky on one side only if a pressure difference of 0.01, 0.1, 0.5 or 1 bar between the pressure in the interior of the hollow space, which can be bounded by a primary seal and a secondary seal, and the pressure in the space outside of the hollow space bounded by the secondary seal is exceeded, and media can flow out of the hollow space via the secondary seal. 
     One advantage that this has is that leakages of a primary valve can be detected more quickly and more easily, because the medium infiltrating behind the leaky primary seal can escape in an easily visible manner into the surroundings or, e.g., into a leakage collecting space via the one-way secondary seal. 
     Moreover, pressure changes, e.g., due to temperature changes, between a hollow space bounded by a primary seal and a secondary seal can advantageously be compensated for and consequently unnecessary thermal and mechanical loads on a primary seal, which can lead to damage or impaired function of the main seal, can be minimized. 
     Furthermore, it can simultaneously advantageously be possible, e.g., during cleaning processes, e.g., to reduce or avoid the risk of the penetration of cleaning liquid or other liquids or unwanted media into the hollow space between the secondary seal and primary seal. 
     In addition, a one-way secondary seal can be provided in such a manner that, on the side of its sealing effect, it can withstand maximum pressures up to 20, 30, or 40 bar, at least for a short time, i.e., for at least for 1, 5, or 10 s. This has the advantage that the secondary seal can remain functional even in the event of pressure hammers. 
     Apart from that, the term hollow space should be taken to mean, for example, among other meanings, clearances and/or gaps between different process valve components, as well as hollow spaces and/or bores within the same process valve component. 
     Likewise, for example, a conically tapered groove for holding a secondary seal can be formed by component walls or component wall parts of different process valve components, or from component walls or component wall parts of the same process valve component. 
     The primary seal(s) of the process valve can thereby be executed as radial or axial seat seal(s) and/or as seat seal(s) with simultaneous radial and axial sealing effects. 
     Furthermore, it is noted that in the following the term secondary seal is always to be understood as a one-way secondary seal. 
     A secondary seal can be incorporated into a conically tapered groove with an initial tension, whereby the aperture angle of the conically tapered groove can lie between 15° and 45°. 
     The pressure generated by the media flowing against the secondary seal in the direction of the broadening direction of the conically tapered groove can thereby press or deform the secondary seal in the direction of the broadening direction of the conically tapered groove, so that the secondary seal can be leaky in the direction of the broadening direction of the conically tapered groove. 
     The initial tension of the secondary seal can thereby pull the secondary seal into the groove bevel or groove in the tapering direction of the conically tapered groove or it can hold the secondary seal in the same. This has the advantage that the secondary seal is not carried away by media that flow in the direction of the broadening direction of the conically tapered groove and/or the secondary seal does not detach from the conically tapered groove. 
     The secondary seal can, however, also be incorporated into the conically tapered groove without an initial tension, and the aperture angle of the conically tapered groove can lie between 8° and 30°, preferably between 12° and 18°. The secondary seal can, however, thereby be incorporated such that it is pressed into the groove or is pressed between the groove walls. The pressing can be generated, among other ways, by, e.g., the intrinsic weight of the component element, e.g., a valve disk part, lying above the secondary seal as seen in the direction of gravity, or also by screwing together the components that form the groove. 
     In the case of media flowing out of the hollow space or in the direction of the tapering direction of the conical groove, the secondary seal seals and is pressed into the tapering groove. In contrast, if a medium flows against the secondary seal from the direction of the broadening direction of the conically tapered groove, the secondary seal can, due to the pressure of the flowing medium, push further in the direction of the broadening direction of the conically tapered groove and consequently, due to a partial loss of the pressing, the secondary seal can become permeable to the aforementioned medium that is flowing out of the hollow space. 
     The secondary seal can be provided in such a manner that its deformation under the effect of pressure, e.g., pressure differences of up to 0.1, 1 or 10 bar between the pressure in the interior of the hollow space, which can be bounded by a primary seal and a secondary seal, and the pressure in the space outside of the hollow space bounded by the secondary seal, generated, e.g., by the media flowing out of the hollow space, does not exceed half the mean cord thickness of the secondary seal. 
     This hinders advantageously the secondary seal from being carried along by the media flowing out of the hollow space or in the direction of the broadening direction of the conically tapered groove and/or from becoming detached from the conically tapered groove. 
     The secondary seal can be executed as a contour ring, for example, as an O-ring. 
     The geometric form of the secondary seal can be a body of rotation, e.g., a torus, with a preferably circular or elliptical cross-section. Other cross-section geometric forms are also conceivable for the secondary seal, however, such as, e.g., trapezoidal cross-sections. 
     The secondary seal can be made of, for example, an elastomer, e.g., a terpolymer elastomer such as EPDM (ethylene propylene diene monomer), or of a thermoplast, e.g., PTFE (polytetrafluoroethylene), and it can have Shore hardnesses between 50 and 100, preferably between 60 and 80. 
     The stiffness or Shore hardness of the secondary seal can prevent or hinder the secondary seal from buckling or being carried along with media flowing in the direction of the broadening direction of the conically tapered groove. 
     The secondary seal can be used in a process valve which is executed as a single seat valve with a one-piece or multi-piece valve disk. 
     In the case of a process valve executed as a single seat valve with a one-piece or multi-piece valve disk, a hollow space bounded by a primary seal and a secondary seal can extend partially up to the clearance between a valve stem and a valve stem housing, and connected to the secondary seal boundary, which is facing away from the flow direction of the media from the direction of the hollow space, can be an opening, through which the media flowing out of the one-way secondary seal from the direction of the hollow space interior can escape into the surroundings or into a process valve housing part, e.g., a leakage collecting space. 
     In this way, slightly leaky primary seals in single seat valves can be detected advantageously, because in the event of leaky primary seals, escaping leakages can be detected more easily. On the other hand, it is simultaneously possible advantageously to prevent, e.g., during cleaning processes, e.g., cleaning liquid from penetrating into the hollow space between secondary seal and primary seal. 
     It is thereby noted that a valve stem can be executed in a process valve with or without a balance. 
     According to the disclosure, a secondary seal can also be executed in a process valve as a double seat valve with a first one-piece or multi-piece valve disk and a second one-piece or multi-piece valve disk. 
     It is thereby possible, e.g., between the first valve disk and the second valve disk, for there to be an intermediate hollow space into which media flowing against the process valve can penetrate through the secondary seal of the upper valve disk and/or through the secondary seal of the lower valve disk and/or in the case of leaky primary seals, through the primary seal of the upper and/or lower valve disk, and collect. 
     This intermediate hollow space can consequently, e.g., in the closed position, advantageously serve as a safety space or leakage space. 
     The intermediate hollow space can additionally have a run-off via which the media that have penetrated into the clearance can flow out or be suctioned off. 
     In the case of seat lifting or lifting of the first or second valve disk, it is advantageously possible for no medium to penetrate into the valve disk, i.e., e.g., into a hollow space bounded by a secondary seal and a primary seal within a valve disk, and consequently, e.g., to avoid the penetration of cleaning liquid, other liquids or unwanted media. 
     By way of example for an improved understanding and for illustration of aspects of the disclosure, enclosed figures depict: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged detail cross-sectional view of a one-way secondary seal with initial tension; 
         FIG. 2  is an enlarged detail cross-sectional view of a one-way secondary seal without initial tension; 
         FIG. 3  illustrates a single seat valve; and 
         FIG. 4  illustrates a double valve 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows, by way of example, how a one-way secondary seal  101  can be incorporated into a conically tapered groove  102  with an initial tension. The groove walls  108  and  109  can thereby be formed by the walls or parts of the walls of components/component elements  106  and  105 . The component elements  106  and  105  can thereby belong to the same component or to different components. The aperture angle α of the conically tapered groove  102  can lie, for a secondary seal  101  incorporated with an initial tension, for example, between 15° and 45°. 
     The hollow space  112  lying between the primary seal (not shown) and the secondary seal  101  can be bounded on the secondary seal  101  by the part of the secondary seal  101  indicated as the secondary seal boundary  111  (also nameable as the inner secondary seal boundary). The part of the secondary seal  101  which faces away from the direction  107  from which the media can flow out of the hollow space  112 , is marked here as secondary seal boundary  110  (also nameable as the outer secondary seal boundary). 
     In the case of a pressure difference of at least 0.01, 0.1, 0.5, or 1 bar between a pressure that is present on the inner secondary seal boundary  111  and a pressure that is present on the outer secondary seal boundary  110 , the secondary seal  101  can, in a one-sided manner on the side of the inner secondary seal boundary  111 , be permeable to media that flow against the secondary seal  101  from the hollow space  112 . 
     The secondary seal  101  can be provided in such a manner that its deformation under the effect of pressure, e.g., pressure differences of up to 0.1, 1, or 10 bar between the pressure in the interior of the hollow space, which can be bounded by a primary seal and a secondary seal, and the pressure in the space outside of the hollow space bounded by the secondary seal, generated, e.g., by the media flowing out of the hollow space, does not exceed half the mean cord thickness  103  of the secondary seal  101 . 
     The initial tension and/or the stiffness or Shore hardness of the secondary seal  101  can also prevent the secondary seal from buckling or being carried along in the flow direction  107  of a medium flowing out of the hollow space  112  up to pressures of a maximum of 10, 20, or 40 bar. 
       FIG. 2  shows, by way of example, a secondary seal  201  that can be incorporated into a conically tapered groove  202 , spanned between the groove walls  209  and  210 , without an initial tension. The hollow space  212  bounded by the secondary seal  201  and the primary seal (not shown) can open, e.g., into a gap  208  between components  206  and  205 . If there is pressure present on the outer secondary seal boundary  210 , meaning the part of the secondary seal  201  that faces away from the direction  207  from which the media can flow out of the hollow space  212  or gap  208 , the secondary seal  201  can be pressed in the tapering direction of the groove  202  and consequently seal against media which flow against the outer secondary seal boundary  210 . 
     The secondary seal  201  can, however, also be incorporated such that it is already pressed in, e.g., due to the intrinsic weight of a component which lies above the secondary seal  201  when seen in the direction of gravity, and which, for example, presses the groove wall/groove top  209  together with the secondary seal  201  against the groove wall/groove bottom  210 , or by means of screwing and thus pressing together the groove walls  209  and  210  and which can press the enclosed secondary seal  201 . 
     The aperture angle β of the conically tapered groove for a secondary seal incorporated without an initial tension can thereby lie between 8° and 30°, preferably between 12° and 18°. 
     If now a medium flows out of the hollow space  212  or out of the gap  208 , e.g., from the direction  207 , against the secondary seal  201  or the inner secondary seal boundary  211 , the secondary seal, due to the pressure of the flowing medium, can slide farther in the direction of the broadening direction of the conically tapered groove and consequently become permeable to the aforementioned medium flowing out of the hollow space  212  due to a partial loss of the pressing. 
     The secondary seal  201  can be provided in such a manner that its deformation under the effect of pressure, e.g., pressure differences of from 0.1 to 10 bar between the pressure in the interior of the hollow space  212 , which can be bounded by a primary seal and a secondary seal, and the pressure in the space outside of the hollow space  212  bounded by the secondary seal  201 , generated, e.g., by the media flowing out of the hollow space  212 , does not exceed half the mean cord thickness  203  of the secondary seal  201 . 
     It is also possible for the stiffness or Shore hardness of the secondary seal  201  to prevent the secondary seal from buckling or being carried along in the flow direction  207  of a medium flowing out of the hollow space  212  or the gap  208  up to pressures of a maximum of 20, 30, or 50 bar. 
       FIG. 3  depicts, by way of example, a process valve as a single seat valve  314  which can have a two-piece valve disk  309  with a first valve disk part  315  and a second valve disk part  316 . 
     A primary seal  303  and a secondary seal  301  can bound a hollow space  308  that can be located between the valve disk parts  315  and  316 , and can also enclose at least partially the clearance  305  between the valve stem  306  and valve stem housing  307 . The valve stem  306  can be executed with (as shown) or without a balance. 
     Media flowing out of the hollow space  308  that, for example, penetrate into the hollow space  308  via a leaky point of the primary seal  303  can escape into the surroundings or into a process valve housing part, e.g., a leakage collecting space, through the secondary seal  301  and, e.g., through an opening  304  connected to the secondary seal and located between the valve stem  306  and the valve stem housing  307 . 
     The conically tapered groove  302  for holding the secondary seal  301  can thereby be formed, e.g., by a part  317  of the valve stem  306  and a part  318  of the valve stem housing  307 . The secondary seal  301  can thereby be incorporated into the conically tapered groove  302  with an initial tension and/or by being pressed in. 
     In this way, slightly leaky primary seals in single seat valves can be detected advantageously, because in the event of leaky primary seals, leakages can be detected more easily. On the other hand, it is simultaneously and advantageously possible to prevent, e.g., during cleaning processes of the valve disk  309 , the valve stem  306 , or the valve stem housing  307 , cleaning liquid from penetrating into the hollow space  308  between the secondary seal  301  and the primary seal  303 . 
     Apart from that,  FIG. 3  depicts, by way of example, a single seat valve in the open position, in which, e.g., the media flow  311  can flow between the pipes  312  and  313 . The seat  310  of the single seat valve can lie, for example, on the pipe  312 . 
       FIG. 4  depicts, by way of example, a process valve as a double seat valve  404 . A double seat valve  404  can thereby have a first valve disk  414  and a second valve disk  413 . 
     The valve disks  413 ,  414  can be multi-piece. E.g., the first valve disk  414  can consequently contain a first valve disk part  417  and a second valve disk part  418 , and likewise the second valve disk  413  can contain a first valve disk part  416  and a second valve disk part  415 . It is thereby conceivable that the valve disk parts of a valve disk can be screwed together. 
     The first valve disk  414  can have a hollow space  403  that can be bounded by a primary seal  402 , which can be executed so as to have, e.g., a radial effect, and a secondary seal  401 . Parts of the hollow space  403  can thereby be executed as bores, e.g. bore  411 , which advantageously can conduct media possibly penetrating through a leaky point of the primary seal  402  better to the secondary seal  401 , from which point it can escape again out of the hollow space  403 . The secondary seal  401  can thereby be incorporated into the conically tapered groove  422  with an initial tension and/or by being pressed in. The groove walls  424  and  425  of the groove  422  can thereby be formed, e.g., by a part of the valve stem  412  and a part of the second valve disk part  418 . It is also possible, however, that the groove walls  424 ,  425  are formed by the same component, e.g., valve disk part  418 . 
     The second valve disk  413  can also have a hollow space  408  that can be bounded by a primary seal  406 , which can be executed so as to have, e.g., an axial and/or radial effect, and a secondary seal  407 . Parts of the hollow space  408  can thereby be executed as bores, e.g., bore  419 , which advantageously can conduct media possibly penetrating through a leaky point of the primary seal  406  better to the secondary seal  407 , from which point they can escape again out of the hollow space  408  and, for example, be drawn off via a clearance  421  between the first  416  and the second  415  valve disk part of the second valve disk  413 . 
     The secondary seal  407  can thereby be incorporated into the conically tapered groove  423  with an initial tension and/or by being pressed in. The groove walls  426  and  427  of the groove  423  can thereby be formed, e.g., by a part of the first valve disk part  416  and a part of the second valve disk part  415 . 
     Between the first valve disk  414  and the second valve disk  413  it is possible for there to be an intermediate hollow space  409 , into which, e.g., in the closed position (as shown) of the double seat valve  404 , in the event of a leaky primary seal  402  and/or leaky primary seal  406 , a medium can penetrate into the intermediate hollow space  409 . 
     In the event of, e.g., a leaky primary seal  402 , a medium can thereby first penetrate into the hollow space  403  and escape into the intermediate hollow space  409  via the secondary seal  401 . In the closed position of the double seat valve  404  in the event of leaky primary seal  402 , it is also possible that, e.g., a medium can penetrate into the intermediate hollow space through a gap between the first valve disk and seat  405  of the double seat valve  404 . 
     The intermediate hollow space  409  can consequently advantageously serve as a safety space for catching leakage. 
     A medium can flow out of or be suctioned out of the intermediate hollow space  409  through an opening  420  in the second valve disk  413 , or in the first valve disk part  416  of the second valve disk  413 , to which can be connected, for example, a clearance  421  between the first  416  and the second  415  valve disk part of the second valve disk  413 . 
     In the open position of the double seat valve  404 , e.g., when switching or, for example, for a flush cleaning, and intact primary seals  402  and  406 , the secondary seals  401  and  407  prevent a medium from being able to penetrate into the hollow spaces  403  and/or  408 . 
     The described one-way secondary seal can, in addition to the process valves cited above by way of example as single seat valve and double seat valve, also be used, e.g., in slanted seat valves, shuttle valves, tank bottom valves or double seal valves, or in process valves with valve disks, particularly with multi-piece valve disks.