Patent Publication Number: US-2018045443-A1

Title: Refrigerant valve arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage application of International Patent Application No. PCT/EP2015/078931, filed on Dec. 8, 2015, which claims priority to European Patent Application No. 15157775.6, filed on Mar. 5, 2015, each of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a refrigerant valve arrangement comprising a housing having an inlet and an outlet and defining a main flow direction, a first valve having a first valve axis, and a second valve having a second valve axis. 
     BACKGROUND 
     Such a refrigerant valve arrangement is known, for example, from U.S. Pat. No. 7,328,593 B2. The first and second valves are in form of shut-off valves which are used to close the inlet and the outlet in case that service or repair has to be performed at other parts of the valve arrangement between inlet and outlet. 
     However, the first shut-off valve and the second shut-off valve have to be arranged in the flow path of the refrigerant flowing through the refrigerant valve arrangement. These two shut-off valves form an additional flow resistance causing a substantial pressure drop. 
     SUMMARY 
     The object underlying the invention is to have a refrigerant valve arrangement with low pressure drop between inlet and outlet. 
     This object is solved with a refrigerant valve arrangement as described at the outset in that said first valve axis encloses a first angle smaller than 90° with said main flow direction and/or said second valve axis encloses a second angle larger than 90° with said main flow direction. 
     In other words, the valve axis of at least said first valve, which can be a shut-off valve or another kind of valve, e. g. a check valve and of said second valve, which can be a shut-off valve or another kind of valve, e. g. a check valve as well are not longer arranged at a right angle relative to said main flow direction, but are inclined so that a pressure drop caused by the respective shut-off valve can be reduced and minimized. Although the shut-off valves are still present in the flow path through the refrigerant valve arrangement, the pressure drop at least at one of these shut-off valves can be decreased. 
     Preferably said first angle is in a range from 30° to 60°. In a particular preferred embodiment said first angle is approximately 45°. An angle of 45° causes the smallest changes in the direction of flow of the refrigerant flowing through the refrigerant valve arrangement. 
     Preferably said second angle is in a range from 120° to 150°. In a particular preferred embodiment said second angle is approximately 135°. The change of direction of the flow of refrigerant through the refrigerant valve arrangement is smallest with an angle of 135°. 
     Preferably a sum of said first angle and said second angle is in a range of 170° to 190°. In a particular preferred embodiment said sum is approximately 180°. This means that the first valve axis and the second valve axis are inclined with respect to the main flow direction in opposite directions with the same or almost the same angle. 
     Preferably said first valve axis and said second valve axis enclose a third angle in a range of 75° to 105°. In a particular preferred embodiment said first valve axis and said second valve axis intersect each other with said third angle of approximately 90°. This keeps the amount of changes of direction of flow of a refrigerant flowing through the refrigerant valve arrangement as small as possible. 
     In a preferred embodiment said first valve comprises a first valve seat between said inlet and a first chamber, said second valve comprises a second valve seat between a second chamber and said outlet, wherein said first chamber and said second chamber are connected by a channel. Said first valve seat and said second valve seat may be offset to each other in direction of said channel. The channel keeps a flow path between said second chamber and said second valve short and correspondingly keeps pressure losses in this path low. 
     Preferably swirl reducing means are arranged in said first chamber. Refrigerant entering the first chamber tends to form a swirl. Such a swirl produces additional pressure losses. The swirl reducing means contribute to a reduction in such pressure losses. 
     Preferably said swirl reducing means are arranged at a bottom of said first chamber opposite said channel. Refrigerant entering said first chamber will flow along the bottom and will then reach the swirl reducing means. The swirl reducing means prevents the formation of one major swirl that will reduce the flow significantly. Instead may minor swirls be formed, but they will not have the same negative impact on the flow through the valve. 
     Preferably said swirl reducing means are arranged at an end of said first chamber opposite said first valve seat in main flow direction. In other words, the swirl reducing means are arranged in a position shortly before an endwall of the first chamber opposite said first valve seat. This is a position in which most swirl is produced. 
     Preferably said swirl reducing means comprise a ramp-like element having a surface rising in a direction towards said channel. The surface starts at the bottom of said first chamber. This starting point is arranged nearest the first valve seat. Incoming refrigerant reaches the swirl reducing means and is directed by the surface in direction to said channel thus reducing swirl and reducing pressure losses. 
     Preferably said surface comprises a concave curvature. The slope of the surface is small at the beginning and increases along the ramp-like element. This has an advantageous effect when reducing swirl. 
     In a preferred embodiment said ramp-like element is centered in said first chamber in a direction perpendicular to said main flow direction. In this way it is possible to achieve symmetric or almost symmetric conditions which have a positive effect on the swirl forming. 
     Preferably said ramp-like element comprises two flanks connecting said surface to said bottom. The ramp-like element does not extend over the complete width of the first chamber, i. e. the direction perpendicular to the main flow direction, but only to a middle part thereof. This is sufficient to reduce swirl. 
     Preferably said flanks are inclined. In other words, said flank do not extend perpendicular to the bottom of the first chamber but enclose an angle greater 90° with the bottom. 
     In a preferred embodiment said ramp-like element is integral with said housing. When the housing is molded, the ramp-like element is molded together with the rest of the housing. 
     In a preferred embodiment said housing is provided with a hot gas port, said hot gas port in particular opening into a space between said first valve and said second valve, preferably into a space between said third valve and said second valve. Hot gas is used to defrost the evaporator of a refrigeration system. In this embodiment the hot gas port can be used, for example, as hot gas inlet port. This port is preferably arranged between said first and said second valve and in particularly preferred between said third and said second valve. When the third valve is in form of a control valve, this is beneficial because the control valve can be controlled remotely by using a pilot valve such as a solenoid valve, or by a stepper motor actuating the valve. This allows for a controlled closing of the control valve whereby the flow direction of the hot gas through the valve is provided. 
     In a preferred embodiment said hot gas port is a hot gas inlet port opening into said space perpendicular to a plane in which said first valve axis and said second valve axis are located. In other words, the hot gas port is arranged in a sidewall of the housing decoupling the refrigerant lines from a hot gas line. 
     Preferably, said first valve, said second valve, and said third valve are arranged on the same side of said housing. This means that all three valves are accessible from the same side of the housing. When the valve is mounted so that this side is the upper side of the housing, particles will tend to move away from the respective valve seats. This way of the mounting does also mean that particles filtered by the strainer will stay at the bottom and can be removed together with the strainer, when it is serviced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described in more detail with reference to the drawing, wherein: 
         FIG. 1  shows a sectional view of a refrigerant valve arrangement, 
         FIG. 2  shows a top view of a housing of a valve arrangement of  FIG. 1 , 
         FIG. 3  shows a section III-III of  FIG. 2 , 
         FIG. 4  shows a simplified version of a refrigerant valve arrangement, 
         FIG. 5  shows a further embodiment of a refrigerant valve arrangement having a hot gas port and 
         FIG. 6  shows the refrigerant valve in a perspective view. 
     
    
    
     DETAILED DESCRIPTION 
     All Fig. show the same elements with the same numerals. 
       FIG. 1  shows a valve arrangement  1  comprising a housing  2 . Housing  2  comprises an inlet  3  and an outlet  4 . A main flow direction  5  is the direction of a straight line connecting inlet  3  and outlet  4 . 
     A first valve  6  in form of a shut-off valve is located near said inlet  3  and is structured and arranged to interrupt or open a flow path from the inlet to a first chamber  7  within said housing  2 . The first valve  6  comprises a first valve seat  8  and a first valve element  9 . The first valve element  9  can be actuated by means of a first spindle  10  to be moved away from said first valve seat  8  or in a direction towards said valve seat  8 . The direction of movement of the first valve element  9  is termed first valve axis  11 . 
     In a similar way a second valve  12  in form of a shut-off valve is located near said outlet  4 . Said second valve  12  is structured and arranged to open or close a flow path between a second chamber  13  and said outlet  4 . To this end said second valve  12  comprises a second valve seat  14  and a second valve element  15 . The second valve element  15  can be actuated by means of a second spindle  16  to be moved away from said second valve seat  14  or in a direction towards said second valve seat  14 . The direction of movement of said valve element  15  is termed second valve axis  17 . 
     The first valve  6  and the second valve  12  can be embodied other than shut-off valves, e. g. check valves and/or control valves. 
     A third valve  19  in form of a control valve is located between said first valve  6  and said second valve  12 . Said third valve  19  can, for example, be controlled by a number of pilot actuators. 
     A strainer  20  is arranged in first chamber  7 . Strainer  20  is held by holding means  21  which are fixed in housing  2  by bolts  22  or the like. 
     As can be seen in  FIG. 3 , first valve axis  11  encloses a first angleα with said main flow direction  5  which is smaller than 90°. In the present case the first angleα is approximately 45°. Generally it is preferred that the first angleα is in a range from 30° to 60°, although an angle of 45° is an optimum. 
     In the same way the second valve axis  17  encloses a second angleβ with said main flow direction  5 , wherein said second angleβ is larger than 90°. In the present embodiment the second angleβ is 135°. More general it is preferred that said second angleβ is in a range from 120° to 150°, although an angle of 135° is an optimum. 
     The sum of the first angle a and the second angleβ is in a range of 170° to 190°. In a particular preferred embodiment this sum amounts to 180° meaning that the first valve axis  11  and the second valve axis  17  are inclined in a mirror symmetric manner. 
     Said first valve axis  11  and said second valve axis  17  enclose a third angleγ in a range of 75° to 105°. In particular preferred embodiment of this third angleγ is approximately 90°. 
     With the first angle a and the second angleβ are chosen as mentioned above the necessary changes in the direction of flow of refrigerant through the refrigerant valve arrangement  1  can be minimized. Since each change of direction of flow causes a pressure drop the inclined arrangement of the first valve axis  11  and/or the second valve axis  17  can minimize the pressure drop caused by such a change of direction of flow accordingly. Therefore, with the angled first valve axis  11  and/or the angled second valve axis  17  pressure losses can be minimized. 
     As can be seen in  FIGS. 1 and 2 , the first valve  6 , the second valve  12  and the third valve  19  are arranged on the same side of the housing  2 . This is the side which is shown in  FIG. 2 . In other words, all three valves  6 ,  12 ,  19  are accessible from this side of the housing, for example for service purposes. The valve  1  is designed to be mounted in the position shown in  FIG. 1 , so that the three valves  6 ,  12 ,  19  are mounted on the “upper side” of the housing  2 . This means that particles will tend to move away from the valve seat  8 ,  14  due to gravity. Particles filtered by the strainer  20  will stay at the bottom and can be removed together with the strainer  20 , when it is serviced. 
     As can be seen in  FIG. 3 , the first valve seat  8  and the second valve seat  14  are offset relative to each other in a direction  23  of channel  18 . This is an additional measure for minimizing the changes of direction of flow of a fluid through the refrigerant valve arrangement  1  and to minimize pressure drops. 
     Furthermore, swirl reducing means  24  are arranged in said first chamber  7 . Swirl reducing means are arranged at a bottom  25  of said first chamber  7 , wherein said bottom  25  is located opposite said channel  18 . The swirl reducing means  24  are arranged at an end of said first chamber  7  opposite said first valve seat  8  in main flow direction  5 . Swirl reducing means  24  comprise an element  26  and is in one piece with housing  2 . The element  26  can, for example, be ramp-like and comprises a surface  27  rising in a direction towards said channel  18  when viewed in main flow direction. This surface  27  comprises a concave curvature. Said element  26  can have another form as long as it prevents the formation of one big swirl and forms instead one or more small swirls. 
     As can be seen in  FIG. 2 , the ramp-like element  26  is centered in said first chamber  7  in a direction perpendicular to said main flow direction  5 , i. e. relative to a middle plane  29  of housing  2 . The ramp-like element comprises two flanks  28  connecting said surface  27  to said bottom  25 . The flanks  28  are inclined with respect to said bottom  25 , i. e. they enclose an angle larger than 90° with said bottom  25 . Incoming refrigerant fluid reaching swirl reducing means  24  is directed towards channel  18  thereby reducing swirl and pressure losses caused by the swirl. 
       FIG. 4  shows a further valve arrangement  1  in a simplified version. Same elements are referred to with the same reference numerals in all figures. 
     A main difference can be seen in that a first chamber  7  has a slightly different form because the strainer  20  is omitted and therefore no accommodation space for strainer  20  is necessary. 
     However, the refrigerant valve arrangement according to  FIG. 4  shows the same first angleα between said first valve axis  11  and said main flow direction  5 , said first angleα being approximately 45°. Furthermore, said refrigerant valve arrangement  1  have the same second angleβ of approximately 135° between said second valve axis  17  and said main flow direction  5 . Finally swirl reducing means  24  are arranged showing a ramp-like element  26  with a concave rounded surface  27  preventing formation of a big swirl and reducing corresponding pressure losses. 
       FIG. 5  shows a further embodiment of a refrigerant valve arrangement corresponding essentially to the one shown in  FIG. 1 , however, from the opposite side. In this case the inlet  3  is shown at the right hand side and the outlet  4  is shown at the left hand side. Consequently the flow direction  5  is opposite to that shown in  FIG. 1 . 
     The first vale  6  is shown in opened condition, i. e. the first valve element  9  is lifted off from the first valve seat  8 . 
     In the same manner the second valve  12  is shown in open condition in which the second valve element  15  is lifted off the second valve seat  14 . 
     In a sidewall of the housing  2  a hot gas inlet port  30  is located. The hot gas inlet port  30  is arranged between the first valve  6  and the second valve  12  and in particular between the third valve  19  and the second valve  12 . It is arranged in a side wall of the housing  2 , i. e. it opens perpendicular to a plane in which the first valve axis  11  and the second valve axis  17  are located. 
     The positon of the hot gas inlet port  30  is beneficial in particular in case the third valve  19  is a control valve, as shown. The control valve can be controlled remotely by using a pilot valve, such as a solenoid valve, or the third valve  19  can be a stepper motor actuated valve. This allows for a controlled closing of the third valve  19  whereby the flow direction of the hot gas through the valve is provided. 
     As can be seen in  FIG. 6 , the hot gas port  30  is connected to a hot gas line  31  extending basically perpendicular to the housing  2  so that it is possible to decouple the hot gas line  31  and the refrigerant lines which have to be connected to the inlet  3  and the outlet  4 . 
     While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.