Patent Publication Number: US-2007095402-A1

Title: Pressure reducer

Description:
TECHNICAL FIELD  
      The invention relates to pressure reducer assembly with an inlet and an outlet adapted to be connected through a valve, having a fixed valve disc and a valve seat body cooperating with the valve disc, the valve seat body adapted to be set by a lifting member, which is exposed to the outlet pressure in a closing direction against the bias of a helical spring.  
     PRIOR ART  
      Pressure reducers are used to limit the outlet pressure of a liquid to a given pressure level. They comprise a valve which is controlled by a lifting member. The lifting member, usually a diaphragm, is exposed to the outlet pressure against the effect of a preload. The preload is normally a spring. If the outlet pressure increases the valve is further opened. Pressure reducers are normally integrated in a casing with an inlet and an outlet. The diaphragm serving as a lifting member is fixed in the casing.  
      In pressure reducers of the prior art, the valve disc of the valve is fixed with respect to the casing while the valve seat body, serving as a valve seat and at the same time as a lifting member, is movable relative to the fixed valve disc. Thereby a diaphragm likely to be damaged during long time operation can be avoided.  
      In a known pressure reducer assembly the outlet and the inlet are coaxially arranged in a pipe. The valve passage extends in a radial direction perpendicular to the axis of the inlet and the outlet. The helical spring serving as a preload is arranged in a projecting casing portion.  
     DISCLOSURE OF THE INVENTION  
      It is an object of the invention to provide an assembly of the above mentioned kind which is particularly compact and simple. It is a further object of the invention to provide a pressure reducer assembly which can be integrated inside a pipe. Further objects of the invention will be described below.  
      As claimed in the invention, this object is achieved with a pressure reducer of the above mentioned kind, in that 
          (a) the inlet and the space upstream of the valve seat are in fluid communication through an axial bore hole in a valve spindle which is connected to the valve disc,     (b) the valve seat body is pot shaped and moveably guided on the valve spindle,     (c) the helical spring surrounds the valve spindle coaxially to the bore hole and acts between a spring abutment provided at the valve spindle and the pot shaped valve seat body.        

      In such an assembly the valve passage and the valve spindle extend coaxially between the inlet and the outlet. Thereby the pressure reducer can be integrated into the inside of a pipe without parts of the assembly projecting towards the outside. There is no need to make use of an expensive and sensitive diaphragm. The outer diameters can be kept small by using the inner space of the valve spindle as a passage. Only a valve seat body is required.  
      Preferably the entire assembly is adapted to be inserted in one piece into a tube shaped casing like a cartridge. Then the pressure reducer can be easily exchanged and/or serviced.  
      Preferably the spring abutment is pot-shaped and provided downstream with an annular groove wherein the helical spring is positioned. Thereby a particularly compact assembly is achieved.  
      A cylindrical dirt trap can be provided in the inlet.  
      The valve disc of a preferred embodiment of the invention is arranged at the outlet side end of the valve spindle and the bore hole in the valve spindle is connected to a hollow space upstream of the valve seat through a radially extending passage. The water flows, therefore, from the inlet through the valve spindle, through the radial passage into the hollow space before the valve seat. From there it reaches the outlet through the opened valve.  
      An embodiment is described below in greater detail with reference to the accompanying drawings. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a cross sectional view of a pressure reducer in an open position.  
       FIG. 2  is an enlarged view of the pressure reducer of  FIG. 1  in a closed position.  
       FIG. 3  shows the pressure reducer of  FIG. 2  in an open position  
       FIG. 4  shows the pressure reducer integrated into a pipe. 
    
    
     DESCRIPTION OF THE EMBODIMENT  
       FIG. 1  shows a fitting  10  with a pressure reducer  12 . The fitting  10  comprises an inlet  14  for connection to a drinking water supply (not shown). The inlet  14  is adapted to be shut off by a shut-off valve  16 . The pressure reducer generally denoted with numeral  12  is provided between the shut-off valve  16  and an outlet  18 . The pressure reducer  12  is arranged in a casing part  20  integrated in a fitting casing  22 . In operation water flows from the inlet  14  through a passage  24  into an inlet chamber  26 . The casing part  20  is tube-shaped, the center axis defining an angle with the center axis of the rest of the casing. A cylindrical dirt trap  28  is arranged in the inlet chamber  26  covering the inlet chamber  26  from the passage  24 . At an end  30  the casing part  20  is provided with a removable lid  32 . In such a way the inside of the tube shaped casing part  20  is accessible, for example, for servicing or for exchanging the pressure reducer.  
      The pressure reducer comprises a casing fixed valve disc assembly and a movable valve seat body assembly ( FIG. 2 ). The casing fixed valve disc assembly comprises a valve spindle  34 . The valve spindle  34  is elongated and provided with an axial center bore hole  36 . On the inlet side the center bore hole  36  ends in the inlet chamber  26 .  
      On the inlet side a pot-shaped spring abutment  38  is provided coaxially around the valve spindle, the spring abutment being screwed on the valve spindle  34 . The spring abutment  38  is also provided with a passage in the range of the bore hole  36 . The other, outlet side end  40  of the valve spindle  34  is slightly wider. A sealing portion  42  acting as a valve disc is screwed into the head formed in such way. The sealing means cooperates with a sealing  44  arranged in an annular groove in the head  40  of the valve spindle  34 .  
      A sealing  46  in the form of an O-ring is arranged between the pot-shaped spring abutment  38  and the valve spindle  34  tightly fixed thereto. The spring abutment  38  is provided with a deep annular groove  48  which is open in a downstream direction. Two concentric cylindric walls  52  and  54  are defined by the annular groove  48 . A helical spring  50  is arranged in the annular groove  48  supported on the spring abutment  38  at the end of the annular groove  48 . The spring abutment is sealed against the casing  20  with a sealing  58  and screwed thereto. Atmospheric pressure is present in the space around the spring  50 , because it is connected to the outside of the casing by an opening  51 .  
      The spring  50  is effective on the valve seat assembly. This is movably guided on the casing fixed valve spindle  34 . The valve seat assembly comprises a shiftable sleeve  60  and a valve seat body  62  screwed thereon. The valve seat body  62  is pot-shaped and cooperates with the valve disc  42  to form a control valve. A sealing  64  is provided between the valve seat body  62  and the shiftable sleeve  60 .  
      The shiftable sleeve  60  is essentially tube-shaped. It is guided on the valve spindle  34  with its upstream portion and sealed against it with a sealing  66 . The inner diameter of the shiftable sleeve  60  increases in the range of the head of the valve spindle  34 . Thereby a hollow space  68  is formed between the valve spindle  34  and the shiftable sleeve  60  in the range before the valve. The helical spring  50  pushes against the shiftable sleeve.  
      On its outside the shiftable sleeve is provided with an annular groove with a sealing  70  therein to seal the shiftable sleeve against the casing  20 .  
      In the range of the head the valve spindle  34  is provided with a radially extending transversal bore hole  72 . It can also be seen in  FIG. 4  showing a different embodiment, in another cross section. The space before the valve is connected to the inlet chamber  26  through this transversal bore hole  72  and the passage  36 .  
      The pressure reducer operates as follows:  
      The outlet pressure in the outlet is effective on the annular outer surface of the valve seat body  62  against the power of the helical spring  50 . Thereby the valve seat assembly is pushed towards the upper left in  FIG. 2  from the valve seat body  62  and the shiftable sleeve  60 . The annular gap of the control valve between the fixed valve disc  42  and the valve seat  74  of the valve seat body  62  is reduced. If the outlet pressure in the outlet drops the forces on the valve seat body  62  will be smaller. The force of the helical spring  50  overcomes the outlet pressure and moves the valve seat assembly towards the upper left in  FIG. 1 , i.e., away from the fixed valve disc  42 . Thereby the annular gap is increased so that the outlet pressure can increase again. This situation is shown in  FIG. 3 . The outlet pressure effective on the valve disc is absorbed by the valve spindle  34  and thereby by the casing.  
      The embodiment shown in FIGS.  1  to  3  is an embodiment, where the entire pressure reducer assembly is installed with an angle into the fitting. Thereby the assembly is accessible through the lid  32  at all times. However, with suitable diameters the fitting may well be directly installed into a pipe. This is shown in  FIG. 4 .  
      As the inlet and the outlet  78  are provided at the respective ends of the pressure reducer assembly  80  a linear assembly is achieved without having side passages.  
      Whereas the invention is here illustrated and described with reference to embodiments thereof presently contemplated as the best mode of carrying out the invention in actual practice, it is to be understood that various changes may be made in adapting the invention to different embodiments without departing from the broader inventive concepts disclosed herein and comprehended by the claims that follow.