Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to DE 10 2007 059 315.7 filed on Dec. 7, 2007. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a pressure reducer, in particular for fluid lines, for example water pipes, with a sealing piston as a stop element, an equalization piston as means for pressure equalization, a one-part or multipart connecting means which rigidly connects the sealing piston and the equalization piston, with a valve seat which in conjunction with the sealing piston defines a flow-through opening against which the sealing piston seals when the valve is closed and which extends through the connecting means at least in an open position of the pressure reducer, and with guide means which are in directly or directly connected with the connecting means and which guide an arrangement consisting at least of equalization piston, connecting means and sealing piston in any operating position. 
     The document with the publication of number DE 195 39 239 A1 discloses a pressure reducer having the aforedescribed features. This pressure reducer has a very complex design. It has in addition to an inlet port and an outlet port two additional ports which are used for receiving the components required for pressure regulation. The pressure reducer has a significant installation height compared to other types of fittings. Moreover, the pressure transducer requires a special housing. 
     The applicant has commercially introduced another pressure reducer known as type “D05F”. The type “D05F” pressure reducer is much more compact. In addition to the inlet port and the outlet port, only one additional port is provided, in which the components of the pressure reducer required for regulating the pressure are inserted. The housing can be also used for other fittings if other components need to be inserted in the housing. The type “D05F” pressure reducer has most of the features described above. For guiding the arrangement consisting of equalization piston, connecting means and sealing piston, a funnel is provided as guide means, which is fixedly attached to the housing in the region of the equalization piston and extends in the direction toward the sealing piston or the valve seat, respectively. The funnel is penetrated by the connecting means. The free end of the funnel contacts and guides the connecting means. The funnel therefore operates as guide means for the arrangement consisting of equalization piston, connecting means and sealing piston. This type of guiding is generally sufficient to ensure a reliable operation of the type “D05F” pressure reducer. However, the funnel must have adequate stiffness so as to be able to hold the arrangement consisting of equalization piston, connecting means and sealing piston also under a strong flow and large forces acting on the arrangement. 
     In view of the state-of-the-art, it is an object of the invention to propose a simple and compact pressure reducer, which allows the arrangement consisting of sealing piston, equalization piston, and connecting means to be easily guided. 
     BRIEF SUMMARY OF THE INVENTION 
     The object is attained with the invention in that the guide means are arranged in the region of the valve seat between the sealing piston and the equalization piston. 
     Arranging the guide means according to the invention in the region of the valve seat between the sealing pistons and the equalization piston enables, on one hand, optimal guiding of the arrangement consisting of equalization piston, connecting means and sealing piston and, on the other hand, a compact construction of the pressure reducer. The arrangement need not be guided by the guide means, which are arranged beyond the sealing piston in relation to the equalization piston, thereby realizing a compact design. In addition, the arrangement is guided in the region of its respective ends, so that torque acting on the arrangement can be effectively eliminated. 
     According to the invention, the guide means may be wings which protrude radially from the connecting means. 
     In an open operating position of the pressure reducer, the guide means extend through the valve seat and are preferably guided for movement through, and make contact with, the valve seat and the region immediately abutting the valve seat. 
     The equalization piston, parts of the connecting means and the guide means may be formed as a single part, preferably a plastic part. The plastic part may be an injection molded plastic part. 
     The connecting means of a pressure reducer according to the invention may have a spindle which is screwed into the equalization piston and the sealing piston. The connecting means may include a screw for attaching the sealing piston to the component. 
     The guide means are preferably clamped between the sealing piston and the spindle. 
     A pressure reducer according to the invention may include a sleeve, in which the arrangement composed of the sealing piston, the guide means, the connecting means and the equalization piston are moveably arranged. The sleeve may be made of plastic. 
     The valve seat may be formed on a first end of the sleeve, with the sealing piston cooperating with the valve seat for adjusting the flow through the pressure reducer and thereby the back pressure. 
     In a pressure reducer according to the invention, the guide means may guidedly abut a first region of an inner wall of the sleeve adjoining the first end. Moreover, the equalization piston may guidedly abut a second region of an inner wall of the sleeve adjoining a second end of the sleeve. In this way, the respective ends of the arrangement consisting of sealing piston, guide means, connecting means and equalization piston can be guided through the sleeve. 
     The first region or the valve seat and the second region preferably have the same diameter. In this way, a pressure-compensated device can be obtained, which operates under static conditions, i.e., when the pressure reducer is closed. Under static conditions, the forces operating on the arrangement compensate each other at the preset pressure, so that only the forces caused by the back pressure operate on the arrangement in the closing direction and the forces produced by a spring in the opening direction. 
     The wall of the sleeve may have through openings in a third region of the wall disposed between the first and the second region, through which the fluid flows when the pressure reducer is in an open position. 
     Advantageously, the pressure reducer according to the invention includes a housing, in which the sleeve as well as the arrangement composed of the sealing piston, the guide means, the connecting means and the equalization piston are arranged. 
     The arrangement composed of sealing piston, guide means, connecting means and equalization piston may be urged by the aforementioned spring into an open operating position. With a sufficiently large back pressure, the forces acting on the arrangement produced by the back pressure oppose the spring force and urge the arrangement, in particular the sealing piston, against the valve seat in a closed position. 
     The bias force of the spring can be adjusted for setting the back pressure at which the pressure reducer closes. 
     In a particular embodiment, the pressure reducer may include a means for rejecting suspended matter arranged on the inflow side upstream of the equalization piston. The means for rejecting suspended matter may be a funnel-shaped screen which is penetrated by the connecting means. The screen may include nozzles, which cause suspended material to be suctioned out of the region upstream of the equalization piston. The edge of the screen may be snapped into a groove disposed on the inside of the sleeve. 
     Two exemplary embodiments of the pressure reducer of the invention will be described in more detail with reference to the drawings, which show in: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  a longitudinal cross-section through a first exemplary embodiment, 
         FIG. 2  a cross-section through the first exemplary embodiment taken along the line B-B in  FIG. 1 , 
         FIG. 3  a side view of a second exemplary embodiment, 
         FIG. 4  a perspective diagram of the second exemplary embodiment in a partial cross-section, 
         FIG. 5  a longitudinal cross-section taken along the line A-A in  FIG. 6  through the second exemplary embodiment, and 
         FIG. 6  a top view of the second exemplary embodiment with individual components partially removed. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The first exemplary embodiment of a pressure reducer according to the invention has a housing  10 , which is implemented as a slanted seat housing with an inlet port  10   a  and an outlet port  10   b . The outlet port  10   b  includes a connection for a pressure gauge which is closed with a cover  80 . A seal  130  is inserted between the cover  80  and the housing  10 . 
     A valve insert is inserted in the housing  10 , or more specifically in an connecting socket  10   c  of the housing, with the valve insert composed of the parts indicated with the reference symbols  2  to  70 ,  90  to  120 , and  140  to  160 . 
     The valve insert includes a sleeve  30 . The sleeve  30  has on a first end a tapered edge forming a valve seat of the pressure reducer. This valve seat engages in an opening in the flow path between the inlet port  10   a  and the outlet port  10   b . The sleeve  30  is supported on the housing by a shoulder in the region of the opening and is sealed in this region against the housing by a seal  160 . 
     A circumferential shoulder supporting the sleeve in the connecting socket  10   c  is formed on a second end of the sleeve  30  opposite the first end, wherein a seal  140  is inserted between the sleeve  30  and the housing  10  in the region of the shoulder. The sleeve has a central third region located between the first region abutting the first end and the second region abutting the second end. The third region has longitudinal slits which extend parallel to the longitudinal axis of the sleeve and are delimited by ribs  30   a  connecting the first region and the second region. These longitudinal slits enable fluid to enter the interior of the sleeve  30  from the inlet port  10   a  and to exit the sleeve  30  in the direction of the first end, thereby reaching the outlet port  10   b  of the housing  10 . 
     A circumferential groove is milled in the region of the housing surrounding the center region of the sleeve  30 , so that the incoming fluid flowing through the inlet port  10   a  can flow around the sleeve  30  on all sides and enter the sleeve  30  through the longitudinal slits. 
     The longitudinal slits in sleeve  30  can be covered by a likewise sleeve-like or hollow-cylindrical sieve  40 , which prevents larger particles from passing through the pressure reducer. 
     The inside diameter of the second region of the sleeve  30  is identical to the inside diameter of the sleeve  30  in the region of the valve seat. In this way, a pressure reducer can be realized, which is pressure-equalized under static conditions, i.e., without flow, and is therefore independent of the upstream pressure and pressure variations on the upstream side, which will be described in more detail below. 
     The sleeve is movably inserted into an arrangement which is composed of a plastic part  20 , a screw  90 , a disk  70 , a sealing disk  110 , and a seal  150 . The parts of this arrangement are rigidly connected with one another. 
     The plastic part  20  extends over almost the entire length of the sleeve  30 . In the first region of the sleeve  30 , the plastic part  20  has wings  20  abutting the inner wall of the sleeve  30 . Conversely, on the opposite end of the plastic part  20 , a piston  20   a  is formed which sealingly contacts with the interposed seal  150  the inner wall in the second region of the sleeve  30 . The wings  20   c , which extend radially from a hollow-cylindrical section  20   b  of the plastic part  20 , are fixedly connected to the piston  20   a  by this hollow-cylindrical section  20   b . The plastic part  20  is guided in the sleeve  30  by the piston  20   a  and the wings  20   c.    
     The piston  20   a  of the plastic part  20  forms an equalization piston whose additional function will now be described in detail. The hollow-cylindrical section  20   b  is part of a connecting means, which connects the equalization piston  20   a  with the wings  20   c , which form guide means  20   c.    
     The screw  90 , which is screwed into the hollow-cylindrical section and holds the disk  70  and the sealing disk  110  with the plastic part  20 , forms another part of the connecting means. 
     The combination of sealing disk  110  and disk  70  forms a sealing piston  20 ,  110  of the pressure reducer. The sealing piston  70 ,  110  is fixedly connected with the equalization piston  20   a  by the screw  90  and the hollow-cylindrical section  20   b , which forms a connecting means. The diameter of the sealing disk  110  is greater than the diameter of the sleeve  30  in the region of the valve seat, so that flow through the pressure reducer is prevented when the sealing disk  110 —and hence the sealing piston  70 ,  110 —contact the valve seat.  FIG. 1  illustrates the pressure reducer in this position. 
     However, if the entire arrangement  20 ,  90 ,  70 ,  110  is displaced and the sealing piston  70 ,  110  moves away from the valve seat, then the pressure reducer opens, allowing flow from the inlet port  10   a  to the outlet port  10   b.    
     The pressure for opening the pressure reducer is typically produced by a compression spring  100  supported on the equalization piston  20   a.    
     The sleeve  30  is inserted into the housing  10  of the pressure reducer and is held in the housing by a cap  60 . The cap  60  has in one section an exterior thread, which is screwed into a corresponding interior thread in the connecting socket  10   c  of the housing  10 . The cap  60  has also an interior thread, in which a threaded piece  120  is screwed. The end of the compression spring facing away from the equalization piston  20   a  is supported on of this threaded piece  120 . 
     The threaded piece  120  is fixedly connected with a wing nut  50  which extends through a front opening of the cap  60 . The spacing between the threaded piece  120  and the equalization piston  20   a  can be changed by a rotating the wing nut  50 , thereby changing the bias force of the compression spring  100 . 
     When the pressure reducer is closed, the sealing disk  110  contacts the valve seat. The free surface of the sealing disk  110 , and hence of the sealing piston  70 ,  110 , is subjected to the upstream pressure. The surface of the equalization piston  20   a  facing the sealing piston  70  is also subjected to the upstream pressure. Due to the identical diameter of the sleeve  30  in the region of the valve seat and in the second region, i.e., in the region of the equalization piston  20   a , the forces acting on the arrangement consisting of the plastic part  20 , the screw  90 , the disk  70  and the sealing disk  110  produced by the upstream pressure are identical. However, the forces have different, i.e., opposite directions. The forces therefore cancel each other and the upstream pressure overall does not exert a force on the arrangement  20 ,  90 ,  70 ,  110 . The pressure reducer is therefore independent of the upstream pressure in the closed position. 
     The second exemplary embodiment of the pressure reducer of the invention depicted in  FIGS. 3 to 6  is different in that the second exemplary embodiment is configured for larger volumes flows and hence has a larger nominal diameter. The connection fittings of valves with a large nominal diameter are typically not implemented as threaded fittings, but as flange fittings, which can be flanged to incoming or connecting pipes. 
     A special fitting for connecting a pressure gauge can be omitted, and replaced by bores disposed in the housing  10  of the second exemplary embodiment, which are either closed with a cover  80 , or into which the pressure gauges  70  are screwed. The housing  10  of the second exemplary embodiment is also implemented as a slanted seat housing, in which the additional components (valve insert) of the pressure reducer are inserted. These additional parts are held in the housing  10  by the cap  60 , wherein in this exemplary embodiment the cap  60  is not screwed into the housing, but rather attached to a flange on the housing  10  with screws  180 . 
     A sleeve  30  is first inserted in the housing  10 , wherein the sleeve  30  has the same function as a sleeve  30  in the first exemplary embodiment. A valve seat is formed on the first lower end of the sleeve  30 , wherein the diameter in the region of the valve seat is identical to the diameter of the sleeve  30  on the opposite end, in the region where an equalization piston  190  is movably arranged. 
     Whereas in the first exemplary embodiment the pressure equalization piston, a part of the connecting means and the guide means are fabricated from a plastic part  20 , the equalization piston  190 , the connecting means  200  and the guide means  210  in the larger pressure reducer illustrated in  FIGS. 3 to 6  are assembled from separate parts. 
     The connecting means  200  is formed by a spindle which has an exterior thread on both ends. The exterior threads are, on one hand, screwed into the aforementioned equalization piston and, on the other hand, into a disk  70  which together with a sealing disk  110  forms the sealing piston  17 ,  110  of the pressure reducer. 
     The guide means  210  have wings  210 A which are attached to a disk  210 B. This ring  210 B is placed on the end of the spindle  200  facing the sealing piston and clamped to the spindle  200  with the disk  70 . 
     Because the sleeve  30  has the same diameter in the region of the valve seat as in the region of the equalization piston  190 , the pressure in the pressure reducer of the second exemplary embodiment is also equalized, i.e., is in the closed position independent of the upstream pressure or of variations in upstream pressure. In the closed position, only the back pressure operates on the arrangements composed of the sealing cylinder  70 ,  110 , the spindle  200  and the equalization piston  190 . If the back pressure increases above the preset value, the pressure reducer closes. Conversely, if the back pressure drops below the preset pressure, the compression spring  100  pushes the arrangement composed of the equalization piston  190 , the spindle  200  and the sealing piston  70 ,  110  and also the guide means  210  away from the valve seat, thereby opening the pressure reducer. 
     The back pressure, at which the pressure reducer opens or closes, can be adjusted by moving the threaded piece  120 . However, the construction of this threaded piece is different from the threaded piece described above with reference to the first exemplary embodiment. It has a threaded bore, in which a threaded rod  220  is inserted. This threaded rod extends through the front face of the cap and is provided with a head  230  which includes engaging surfaces for engagement with wrenches. By rotating the head  230  and thereby also the threaded rod  220 , the threaded piece  220  is axially displaced, because it is prevented from co-rotating by a headless screw  240  which is guided in a slot  60 A. The headless screw  240  can be used to indicate the preset pressure of the pressure reducer.

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