Patent Publication Number: US-2016230902-A1

Title: Valve

Description:
The invention relates to a valve with a valve housing through which process medium may flow and in which is located a valve seat encompassing a through-flow orifice and assigned a valve member mounted on a spindle in such a way that the valve member is movable by means of a stroke of the spindle between a blocking position in which the valve member fits up with process-medium-tight sealing against the valve seat, and an open position in which the valve member is lifted from the valve seat, wherein there is accommodated in the valve housing a sealing device through which the spindle passes and which seals the spindle passage, and with a valve drive which has a drive housing and an operating wall arranged movably in the drive housing, which may be subjected to fluid pressure and generates the stroke of the spindle, and wherein there are provided on the valve housing a valve housing interface and on the drive housing a drive housing interface for the connection of valve housing and drive housing. 
     A valve of this type is described for example in EP 0 897 076 B1. The valve disclosed there is designed as a membrane valve and has a valve member in the form of a membrane, which is connected to the spindle via a pressure piece. The spindle in turn is connected to a drive member in the form of a piston. The piston is guided movably in a drive housing. The drive housing has for this purpose a housing top section screwed on to an intermediate piece which is part of the valve housing. The spindle passes through the intermediate piece and is in turn fixed by screws to a base part of the valve housing. The membrane is clamped between the intermediate piece and the base part of the valve housing. The piston chamber of the piston, which may be acted upon by pressure, is therefore bounded by the inner wall of the intermediate piece and the inner wall of the housing top section. 
     In disassembly of the drive, the housing top section is unscrewed from the intermediate piece. In addition it is necessary to break the connection between the spindle and the piston. Another option is to remove the intermediate piece and housing top section together from the rest of the valve housing. This involves loosening the screws between the base part of the valve housing and the intermediate piece. However this also loosens the clamping of the membrane, so that the remaining valve housing base section is now without a membrane and consequently it is no longer possible to block the valve through-flow orifice. 
     The problem of the invention is to create a valve of the type referred to above, which may be assembled and/or disassembled in a simple manner and is characterised by greater functionality than valves known from the prior art. 
     This problem is solved by a valve with the features of the independent claim  1 . Developments of the invention are described in the dependent claims. 
     The valve according to the invention is distinguished by the fact that the drive housing has, in front of the operating wall, a housing base bounding a working space for the operating wall, on which the drive housing interface is provided. 
     The valve according to the invention is divided into several functional modules, each in itself fully functional. So for example the drive housing may be loosened in a simple manner by releasing the interface connection at the interface between drive housing and valve housing. The sealing device accommodated in the valve housing ensures that the valve housing, even with the drive removed, forms a closed unit which may be used separately. In particular, this makes it possible to install the valve housing or the valve fitting without a drive in process medium lines. Without the drive, this is easier than with the drive fitted, due not only to the lower weight but also the smaller overall size. Also, it is possible to perform pressure tests on the valve housing with the drive housing removed, which means therefore that all fluid-side operating steps may be completed before the valve drive is attached. The sealing device accommodated in the valve housing therefore seals the process medium tightly, irrespective of whether or not the valve drive is connected. 
     In principle the valve consists of a valve housing and a valve fitting. As valve drives, it is possible to use fluidic, electrical, magnetic and manual, for example operated by means of a hand wheel, valve drives. Possible valve fittings are angle seat, straight seat or membrane valve fittings. It is therefore possible for the valve to have a valve drive component and a valve housing component, each of which may be in the form of pre-assembled modules which can be put together or separated from one another easily and quickly. 
     In a development of the invention, an operating rod connected to the operating wall passes through the housing base, and sealing means to seal the passage of the operating rod are accommodated in the housing base. 
     In an especially preferred manner the housing base has a bottom base part connected, pressure-tight, to the rest of the drive housing and with an inner wall bounding the working space, and a drive-side interface part with the drive housing interface and connected to the bottom base part. 
     It is possible for the drive-side interface part to be a separate component from the bottom base part, and attached to the bottom base part. 
     In a development of the invention, the valve housing has a valve housing base section, and a fluid-side interface part with the valve housing interface and connected to the valve housing base section. In a preferred manner, therefore, the valve housing interface is formed on the fluid-side interface part, while the corresponding drive housing interface is located on the drive-side interface part. 
     Preferably the fluid-side interface part is a separate component from the valve housing base section and may be attached, in particular releasably, to the valve housing. The fluid-side interface part is preferably hollow-cylindrical in form. Due to this releasable fastening to the valve housing base section, the fluid-side interface part may be replaced easily and quickly as necessary. Altogether, this creates enhanced modularity. Suitable for the releasable connection with the valve housing base section is for example a threaded connection. Alternatively it is possible for the fluid-side interface part and the valve housing base section to be made as one piece. 
     In a development of the invention, the sealing device is accommodated in the fluid-side interface part. 
     Especially suitable for this purpose is the provision of the sealing device in a sealing cartridge, separate from the valve housing, designed as a ready for use pre-assembled module and attached to the valve housing. 
     Valve housing, sealing cartridge and connected valve drive are therefore units made separate from one another, which may be put together or disassembled easily and quickly. This makes possible a rapid and cost-effective replacement of seals which are prone to wear. 
     Expediently the sealing cartridge has a cartridge housing, in which is accommodated a seal assembly including sealing means, biased by spring means against the cartridge housing and fitting up against the spindle with sealing. 
     In a development of the invention, the operating rod and the spindle are or may be connected to one another over a further inner interface. Expediently this further inner interface for the case where the valve housing interface and the drive housing interface are connected to one another is located in a chamber which is closed off from the environment. This prevents the ingress of dirt into the area of the inner interface, 
     In a development of the invention, the operating wall is in the form of an operating piston to which fluid pressure may be applied. The operating piston is expediently part of a fluidic linear drive. A membrane which may be subjected to fluid pressure is also conceivable as an alternative to an operating piston to which fluid pressure may be applied. 
     It is possible that the working space is in the form of a working chamber which may be subjected to fluid pressure. Alternatively, though, it would also be conceivable for the working space to be available only for the accommodation of spring means for pressurisation of the operating wall, with a further working chamber which may be subjected to fluid pressure being provided. 
     In an especially preferred manner the valve includes an attachment part, which may be connected at the valve housing interface with the valve housing instead of the drive housing, and in the attached state presses the spindle into its blocking position. By this means it is thus possible for the valve to be installed in a process medium line with its valve member in the blocking position. 
    
    
     
       Preferred embodiments of the invention are shown in the drawing and are explained in detail below. The drawing shows in: 
         FIG. 1  a longitudinal section through a first embodiment of the valve according to the invention with the valve drive separated from the valve housing and 
         FIG. 2  a longitudinal section through a second embodiment of the valve according to the invention without valve drive. 
     
    
    
       FIG. 1  shows a first embodiment of the valve  11  according to the invention. The valve  11  is suitable for use as a process valve in the processing industry. The valve  11  according to the invention and according to the first embodiment will be explained below by way of example with the aid of a so-called angle seat valve. However the invention may also be applied to a straight seat valve. 
     As shown in particular in  FIG. 1 , the valve  11  has a valve housing  12  in which a through-flow passage  15  extends between an inlet  13  and an outlet  14 . 
     In the case of use in the food processing industry, the valve housing  12  is made expediently of stainless steel. If aggressive substances, for example acid, are used as process media, the valve housing  12  is made expediently of plastic material, which has a greater chemical resistance to such substances. 
     In the through-flow passage  15 , between the inlet  13  and the outlet  14 , is a through-flow orifice  16  which is encompassed by an annular valve seat  17 . Expediently the valve seat  17  is circular in shape. Theoretically, however, a valve seat  17  of oval shape would also be conceivable. The valve seat  17  is assigned a valve member  18 , which in turn is mounted on a spindle  19 . 
     The valve member  18  is shown purely by way of example as a multi-part component, and has in this case a plate  20  provided with a through hole, through which an end section  22  of the spindle may be inserted. The plate  20  is for example welded to the spindle  19 . The valve member  18  also includes a mating piece  23  which is provided with a blind hole type locating orifice  24 , which is provided with an internal thread. Complementary to the latter, there is provided at the end section  22  of the  19  an external thread, with which the mating piece  23  may be screwed on to the end section  22  of the spindle  19 . Clamped between the mating piece  23  and the plate  20  is an annular seal ring  27  which is expediently made of plastic, for example PTFE. 
     The valve member  18  may be moved by means of a stroke of the spindle  19  between a blocking position in which the valve member  18  fits up with its seal ring  27 , fluid-tight, against the valve seat  17 , and an open position in which the valve member  18  is lifted from the valve seat  17 . The stroke of the spindle  19  is generated by its valve drive  28 . 
     The valve drive  28  is shown in  FIG. 1  by way of example with the aid of a fluidic linear drive in the form of a pneumatic piston drive. The valve drive  28  has a drive housing  29 . The drive housing  29  is a self-contained unit which can be pre-assembled, with a hollow-cylindrical housing body  30  given a fluid-tight seal by a housing cover  31  at the top and a housing base  32  at the bottom. The housing body  30  may be made of aluminium, for example as an aluminium extruded part. If necessary, the aluminium  30  may also be cladded with a stainless steel sleeve. Alternatively, however it would also be conceivable to produce the housing body  30  as a stainless steel part. 
     The housing cover  31 , the housing base  32  and the housing body  30  define an interior  33  in which an operating wall  34  in the form of an operating piston, which may be subjected to fluid pressure, is movably guided and divides the interior  33  into two working spaces  35 ,  36  or working chambers. In the exemplary case, a single-acting piston drive is shown, in which one of the two working spaces  35  may be pressurised by compressed air, while in the other working space  36  at least one, in the exemplary case two, resetting springs  37   a ,  37   b  are mounted. Here the arrangement is chosen so that the resetting springs  37   a ,  37   b  press the operating piston downwards to the first working space  35 , leading to pressure on the connected spindle  19  and the valve member  18  and valve seat  17  connected to it. Such a design is also described as Normally Closed. If the first working space  35  is supplied with compressed air, then the operating piston is pressed upwards against the resetting force of the resetting springs  37   a ,  37   b , so that ultimately the valve member  18  is lifted from the valve seat  17 . 
     The operating piston is plate-shaped and permanently connected to an operating rod  38  in the form of a piston rod, which here extends through the operating piston via a through opening  39 . The operating piston is in the exemplary case divided into several annular cylinder sections  41   a - c , stacked one behind the other in the axial direction of a longitudinal axis  40  running through the piston rod and the spindle  19 , and differing from one another in their respective outside diameters. The first cylinder section  41   a  has the largest outside diameter and makes contact with its peripheral surface with the inner wall of the housing body  30 . Formed in the peripheral surface of the first cylinder section  41   a  is an annular sealing groove  42 , in which a seal ring  43 , made in particular of plastic material, is held. The seal ring  43  ensures dynamic sealing between the peripheral surface of the first cylinder section  41   a  of the operating piston and the inner surface of the housing body  30 . Supported on the end face of the first cylinder section  41   a  facing away from the first working space  35  is the first resetting spring  37   a , which rests at the other end on the housing cover  31 . 
     Adjoining the first cylinder section  41   a  of the operating piston is a second cylinder section  41   b , which has a smaller outside diameter. Resting on the end face which there faces away from the working space  35  is the second resetting spring  37   b , which at the other end also rests on the housing cover  31 . Finally, adjoining the second cylinder section  41   b  in the axial direction is a third cylinder section  41   c , in which the through opening of the piston rod is formed. 
     The piston rod extends with a first piston rod section  44   a  into the second working space  36 , while a second piston rod section  44   b  passes through the first working space  35  and is guided out of the drive housing  29  via a cylindrical through passage  45  formed in the housing base  32 . The housing base  32  has a bottom base part  46  which has a fluid-tight connection with the housing body  30  and for example is welded to the latter. Adjoining the bottom base part  46  of the housing base  32  on this side is a first extension  47  which extends into the first working space  35 , while on the other side of the bottom base part  46  a second cylindrical extension  48  is formed, extending downwards from the drive housing  29 . Provided on the valve housing  12  is a valve housing interface  49 , while on the drive housing  29  a drive housing interface  50  is provided for connection of the valve housing  12  and the drive housing  29 . 
     The drive housing interface  50  is provided on a drive-side interface part  51 , which is made as a separate component to the rest of the drive housing  29 . The drive-side interface part  51  is sleeve-shaped and is fitted on to the second cylindrical first extension  48  of the housing base  32 , where it is rotatably connected to the second cylindrical extension  48 , in particular by means of a spring ring connection. The drive-side interface part  51  is brought into engagement with a fluid-side interface part  52 . For this purpose the drive-side interface part  51  has a hollow-cylindrical mounting section  53 , on the peripheral surface of which is formed an external thread  54 . Alternatively it is possible to form an internal thread on the mounting section  53 . Adjoining the mounting section  53  in the axial direction is a base section  55  of greater diameter. 
     The fluid-side interface part  52  is hollow-cylindrical in form and has several functional sections. One of these functional sections is a cylindrical fixing section, on the peripheral surface of which an external thread  57  is formed. Corresponding to this external thread  57  is an internal thread  60  formed on a locating nozzle  58  of the valve housing  12 , by means of which the interface part  52  may be screwed into the valve housing  12 . The locating nozzle  58  is a one-piece component of a valve housing base section  59 . The fluid-side interface part  52  may, because of the screw connection described above, be removed easily from the valve housing base section  59 . In the case of smaller nominal widths it is possible for the interface part  52  and the valve housing  12  to be made as a one-piece component, made for example from cast material. 
     The fluid-side interface part  52  also has a mounting area  61  assigned to the mounting section  53  on the drive-side interface part  51 , with an internal thread  62  formed on its inner wall. As an alternative it would be possible to form an external thread on the mounting area. The end face of the mounting area  61  forms a mating stop face  63 , which is assigned to the stop face  56  on the drive-side interface part  51 . 
     The drive-side interface part  51  and with it the whole drive housing  29  may therefore be screwed into the fluid-side interface part  52 , by which means the drive housing  29  and the valve housing  12  are connected to one another. 
     On screwing-in the drive-side interface part  51  an end position is reached which is defined by the stop of the stop face  56  and the mating stop face  63  which correspond with one another. 
     Also provided is a further inner interface  64 , which serves to connect the spindle to the piston rod. 
     Also belonging to the valve  11  is a sealing device  65  through which the spindle  19  reaches and which has a seal assembly  66  comprising sealing means, biased by spring means and fitting up with sealing against the spindle  19 . The sealing device  65  is accommodated in a sealing cartridge  67 , in the form of a ready for use pre-assembled module which is separate from the valve housing  12 . The sealing cartridge has a cartridge housing  68  which is or may be fastened to the valve housing  12  and in which the spring means for biasing the seal assembly are accommodated. 
     The cartridge housing  68  has several functional sections, including a locating section  69  for holding the seal assembly  66  and the spring means. The locating section  69  is cup-shaped and has an envelope area  70  which envelops the seal assembly  66  and the spring means, and a bottom area  72  provided with a central through hole  71 . 
     The seal assembly is shown by way of example in the form of a V-sleeve, wherein several annular V-sleeves  73  stacked one above the other in the axial direction are provided as single sealing elements. 
       FIG. 2  shows a second embodiment of the valve  11  according to the invention. In contrast to the first embodiment described above, the valve  11  of the second embodiment is altogether designed as a membrane valve. Here too is provided a valve housing  12 , which has an inlet  13  and an outlet  14  and a through-flow passage  15  connecting the inlet  13  and the outlet  14  to one another. Also provided is a through-flow orifice  16  which is strongly tapered compared to the rest of the diameter of the through-flow passage  15 . The through-flow orifice  16  is bounded at one end by an elevation  74 , on which is provided a valve seat  17  for the valve member  18 . The valve member  18  is in the form of a membrane, which is connected to the spindle  19  via connection means. As  FIG. 2  shows, the locating nozzle  58  has an external thread, which may be screwed together with the fluid-side interface part  52  and an internal thread  62  provided there. An annular seal  76  is also inserted between the external thread on the locating nozzle  58  and the internal thread of the fluid-side interface part  52 . 
     A through opening  77 , through which the spindle  19  is guided, passes through the fluid-side interface part  52 . The spindle passage is sealed by an annular seal  78 . 
     This membrane valve is also, therefore, like the angle seat valve described in the first embodiment, sealed fluid-tight with the drive disconnected. The membrane valve maybe installed in a process medium line in the state shown in  FIG. 2 , i.e. it may be fitted without the drive.