Abstract:
The description relates to a device for the regulation of the amount of a medium in a heating or cooling system, comprising a combined valve, which in one and the same valve housing includes one part for pressure difference regulation ( 2 ) and one part for flow limitation ( 3 ), the flow being limited in a stepless, adjustable way, i.e. the device obtaining an adjustable Kvs-value. Also, the chosen Kvs-value can be limited by a plunger, which always can operate with its complete stroke length.

Description:
This application is a national stage completion of PCT/SE2005/001122 filed Jul. 7, 2005 which claims priority from Swedish Application Serial No. 0402206-7 filed Sep. 15, 2004. 
   FIELD OF THE INVENTION 
   The present invention relates to a device for the regulation of the amount of a flow, having an adjustable Kvs-value, in a heating and cooling system. 
   BACKGROUND OF THE INVENTION 
   The object of a device according to the present invention is to keep the flow constant by combining a pressure difference valve with an integrated check device. The check device can also be varied by choosing in a stepless manner a more or less open check device in order to in this way in the separate case let the desired flow reach a chosen pressure difference level. 
   The already known devices, designed to meet these objects, and in these cases primarily pressure difference regulators or flow regulation valves, are impaired by various drawbacks. 
   A device, based on a pressure difference regulator, in principle can limit the flow to a level, which depends on the chosen pressure difference across the valve and the size of the valve, i.e. the flow, which it is chosen to be able to limit the pressure for. The limitation is caused by the fact, that, when a smaller flow is needed, a flow, which is smaller than the predicted one, to the valve, which is related to a definite pressure difference, must be added a valve, which eliminates this too large flow. In this case this separate valve can be allowed to operate with a pressure level, which may cause noise, since the chosen pressure difference valve cannot check this smaller flow and thus not limit the pressure for this smaller flow. Consequently, two different valves must be combined. One pressure difference valve and one flow regulating valve in order to obtain the desirable regulation functioning is of course an expensive solution. 
   A device, based on a flow regulation valve, can of course limit the flow, but such a system must include valves, which also limit the available pressure difference across the flow limitation valve. This means, that regardless of what system of the two mentioned above, which is chosen, the set-up must comprise at least two separate units, one which limits the pressure difference level and one which regulates the flow. 
   In small set-ups, e.g. in small houses, the pressure levels are normally not so high, that the above-mentioned combination of difference- and flow limitation functions are required. In these set-ups radiator valves are used, which can be designed to allow the opening between the cone and the seat of the valve to vary in various ways in order to be able to regulate the flow in a better way. 
   Examples of solutions for small set-ups are described in SE 8600679-8 and in DE 27 56 118. 
   For large set-ups, i.e. often set-ups with high pressure differences, there are constructions, which are based on a limitation of the flow in steps, which arrangement is described in e.g. EP 0 591 873 A 1, and as an alternative a use of a pressure difference valve according to e.g. U.S. Pat. No. 6,196,259 B1. 
   In all these existing solutions the total cost is high, in case a satisfactory functioning in a set-up is to be achieved, partly because several units are required and partly because the existing pressure difference valves often are complicated constructions. Since at least one pressure reducing function and one flow limiting function are required, in most set-ups, the final cost for the client will be high. Two components must be installed and these often require some type of maintenance or control, which means elevated costs. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to counteract and as far as possible eliminate the above-mentioned problem. Also, the invention is to develop the art in this field in various respects. The object of the invention particularly is to develop a complete valve, which can be used during changing operation conditions. 
   These objects are achieved according to the present invention by means of a device of the type described in the Summary of the Invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional characterizing features and advantages of the invention are set forth in the following description, reference being made to the enclosed drawings in which: 
       FIG. 1  is a schematic diagram of a device according to the present invention, being a part of a cooling or heating set-up or plant, the flow regulation valve according to the invention being integrated with an inlet or an outlet line; 
       FIG. 2  is a cutaway view of the valve according to the invention; 
       FIG. 3   a  is cutaway view of a pressure difference regulating part according to the invention: 
       FIG. 3   a  shown in a fully open position; 
       FIG. 3   b  is a cutaway view of a pressure difference regulator part according to the invention, showing a position, in which the passage is partially eliminated. 
       FIG. 4   a  is a flow regulating valve part according to the invention showing the valve fully open; and 
       FIG. 4   b  is a flow regulating valve part according to the invention showing the valve with its cone partially closed; and 
       FIG. 4   c  is a bottom perspective view of the valve in which the stop shoulder for the check device if shown. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  shows the complete flow regulating valve  1 , which comprises a connection  7  for the flow pipe and a connection  8  for the return flow pipe. The valve is provided with measuring outlets to be able to control the actual total drop of pressure across pressure difference part  2  and flow regulating valve part  3 . In connection  4  the pressure in the flow pipe can be measured/registered as can the pressure in the return flow pipe in connection  5 . The construction of the measuring nipples is known in the art. Examples regarding construction and operation are described in i.a. document SE 020 2851-2. 
   Also, the valve is provided with a stop valve  6 , mounted in extended part  9  of return connection  8  of the valve. This stop valve can advantageously be a ball valve, in which is mounted with sealing elements  10  and a stop ball  11  and in which place these parts are fixed in an axial direction by means of a stop nut  12 . 
   The regulating function of the complete valve consists of two interacting parts, which are mounted in the common valve housing  1 . The upper part, which contains a flow regulating valve part  3 , is mounted in the valve housing by fixing top piece  13  to housing  1  by threading a locking nut  14  on the top part of the housing  1  and the lower annular part  15  of the top piece  13  being pressed against gasket  38 , which is inserted into cylinder head  16  of the pressure difference part, which in its turn presses pressure difference part  2  downwards against control plane  18  of valve housing  1 . On upper, outer thread  46  of top piece  13  a protective cover  37  is suitably mounted, which after its installation can be replaced by a suitable type of adjusting means—not shown in the figure. 
   A sealing, in order to prevent outer leakage between the valve housing and the top piece is done by means of O-ring  19 . In a similar way outer leakage via the inner components of flow regulating valve part  3  is prevented by the mounting of O-rings  20  and  21  respectively. 
   The construction of the pressure difference part is shown in  FIG. 3 ,  FIG. 3   a  showing the pressure difference regulating part in its fully open position, i.e. when the spring force of spring  23  presses the cylindrical, basket-like part  24  with its upper sleeve-like part  25  upwards towards cylinder head  16  of the pressure difference part. In order to guarantee a small distance between sleeve-like part  25  and its upper side and the lower side of the cylinder head  16 , the cylinder head is provided with a distance shoulder  42 . This will enable the pressure level, which exists inside components  24  and  24 —the pressure difference-part—having a pressure Pd—to act on as large a surface as possible. In this position, i.e. when the cylindrical basket-like part  24  is in its highest position, passage  26  is fully open between the lower, non movable check portion and the cylindrical basket-like part  24 . 
   In  FIG. 3   b  an operation position is shown, in which spring unit  23  partially has been compressed, passage  26  having been reduced in this way. This operation position is obtained, when the pressure level of inlet side  7 , called Pi, is higher than pressure level Pd, which is obtained after passage  26  in a downstream direction. 
   Thus, when inlet pressure Pi increases, basket-like part  24  will be pressed downwards and will consequently restrict/reduce passage  26  and the result of this will be a pressure loss of from level Pi to level Pd. The pressure difference between Pd and the pressure level of outlet side  8 , called Pr, is chosen to let the Pd-force times the upper surface of sleeve-like part  25  compress spring  23  into a position, in which the spring force jointly with the force, which pressure Pr times the surface, on which Pr acts in space  39  between basket-like part  24  and the inner diameter of the cylindrical casing, is balanced. Thus, the pressure difference between Pd and Pr is constant and not dependent on pressure level Pi of inlet side  7 . This constant pressure difference is the basis of the operation of the flow regulating valve  3 . 
   Thus, in case Pi increases, from the position shown in  FIG. 3   b , spring unit  23  will be compressed additionally and this will in its turn result in a reduction of passage  26 , since the pressure difference between Pd and Pr must be kept constant. Pressure Pr enters into space  39  via slots  29 , which are present in lower cylindrical casing ring  41 . In order to prevent, that the higher pressure Pi will enter into this space  39 , an O-ring  22  is provided, which seals between valve housing  1  and lower cylindrical casing part  41 , and sealing rings  30  respectively, which seals between this cylindric casing part  41  and the cylindrical basket-like part  24 . Also between cylindrical casing  40  and sleeve-like part  25  in the upper end of the pressure difference part there are sealing rings  30 , designed to guarantee partly, that the higher pressure level Pi does not leak into space  39  and partly that sealing rings  30  are provided, designed to provide a low friction between components  24  and  28  and between components  25  and  40  respectively. Low friction is important in order to guarantee, that changes of the input static pressure quickly leads to a new operation position for the movable  24  flow checking part of the pressure difference regulating part. 
   The construction of the flow regulating valve part  3  is shown in  FIG. 4 , which shows the flow regulating valve part  3  fully open, i.e. revolving rotary gate  34  has been rotated by turning the holding case  45  with a pre-adjustment  36 —not shown in the Figs.—into a position, in which passage  43  outwards towards outlet side  8  of the valve is fully open, and simultaneously plunger  31  is positioned in its upper, open or highest position relative to the gasket  38  in the cylinder head  16  of the pressure difference regulating part  2 . 
   The flow regulating valve part  3  will, due to its construction, always make it possible to choose an opening degree, which makes it possible to choose exactly the maximal flow, which is appropriate for the separate application case, and simultaneously it is possible to restrict this flow by means of the rotary movement of rotary gate  34 . 
   The desired maximal flow is guaranteed thanks to the fact, that the pressure difference part always provides a constant difference of the pressure Pd—Pr, maximal drop of pressure, which the flow regulating valve part  3  must than take care of. With this drop of pressure as a starting point it is then possible to choose the flow, which the valve is to provide by rotating rotary gate  34  in a stepless manner, the chosen opening degree corresponding to the desired flow. The rotary gate  34  cooperates with fixed cylindrical valve seat  32 , which is mounted into top piece  13 . On top piece  13  it is advantageous to attach a graduated collar  17 , according to  FIG. 2 , which interacts with a pre-adjustment tool—not shown in the drawings—which is used, when a position for rotary gate  34  is to be chosen in relation to cylindrical valve seat  32 . Pre-adjustment tool gears with holding case  45 , which in its turn rotates rotary gate  34 . 
   Thus, through the described pre-adjustment it is possible to always dimension the opening degree of the valve, the so called Kvs-value, depending on the present need, and thus, it is not necessary to choose a valve having rigid steps between different openings degrees, different flows. 
   In addition to this function, the one with a stepplessly chosen KVS-value, it is also possible to restrict this flow by means of a plunger  31 , which can be displaced in an axial direction by the spindle  33 . The axial movement can always be utilized in its entire length, regardless of the opening degree, which has been chosen by means of rotary gate  34 . This means, that it is really possible to regulate the flow, regardless of whether the valve/plunger is to restrict a small or a large flow. 
   When the plunger reaches its lowest position, i.e. when the valve is to stop the flow entirely, this has been secured by letting the plunger be lowered and sealed against rubber gasket  38 , provided on top of cylinder head  16  of the pressure difference valve. In this position, when the plunger seals, pressure level Pi, present in the system, would press the cone upwards. By introducing a small slot  44  between spindle  33  and plunger  31  a small leakage flow up to the upper side of the plunger is permitted and in this way a decompression of the plunger is achieved and consequently the undesirable effect of a pressure/force increase on the plunger is prevented and in this way the sealing functioning is secured. The decompression also implies, that the closing per se can be accomplished through minor forces, and it will be easy to operate the valve. 
   The flow regulating valve part  3  is provided with O-rings  20  and  21  in order to prevent an outer leakage via the inner parts in top piece  13  and also an O-ring  27  in order to limit an inner leakage. O-ring  19  will prevent an outer leakage between top piece  13  and valve housing  1 . 
   In  FIGS. 4   b  and  4   c , which shows the check valve from below, the flow regulating valve part  3  is seen in a position, where the opening degree of the flow regulating valve part  3  is limited to a certain extent. The rotary gate  34  has in this situation been rotated, the opening in relation to the cylindrical valve seat  32  having been reduced. Simultaneously this lateral view shows plunger  31  in a position, in which it has been removed downwards somewhat in relation to its upper position, its starting position. The rotary gate  34  can in principle be rotated 180° and in its final position, when the opening between the rotary gate and the fixed cylindrical valve seat  32  is completely closed, the rotary gate stops against an inner shoulder  47  on cylindrical valve seat  32 . The valve seat  32  has also an opening, a recess (180°), which means, that the opening—when the valve is fully open—is a 180°—segment, the height of which is “a” according to the figure. 
   Of course, the solution described above for a device, designed for a flow regulation, can be modified to some extent within the scope of the inventive idea. 
   COMPONENT LIST 
   
       
         1 =valve housing 
         2 =pressure difference regulation part 
         3 =flow regulating valve part 
         4 =measuring nipple—Pi level 
         5 =measuring nipple—Pr level 
         6 =stop valve 
         7 =flow pipe connection 
         8 =flow pipe return connection 
         9 =extended part of the valve housing 
         10 =sealing element 
         11 =stop ball 
         12 =stop nut 
         13 =top piece 
         14 =locking nut 
         15 =lower annular portion of the top piece 
         16 =cylinder head of the pressure difference part 
         17 =graduated collar 
         18 =control plane of the valve housing 
         19 ,  20 ,  21 ,  22 =O-rings 
         23 =spring 
         24 =cylindric basket-like part 
         25 =sleeve-like part 
         26 =passage 
         27 =O-ring 
         28 =lower, not movable check portion 
         29 =slot 
         30 =sealing ring 
         31 =plunger 
         32 =cylindrical valve seat 
         33 =spindle 
         34 =rotary gate 
         35 =spring 
         37 =protective cover 
         38 =gasket 
         39 =space 
         40 =cylindrical casing 
         41 =lower casing ring 
         42 =distance shoulder 
         43 =passage 
         44 =slot for leakage flow 
         45 =holding case 
         46 =outer thread 
         47 =shoulder 
         48 =adjusting device 
         49 =cut