Abstract:
An accumulator is disposed in a refrigerant circuit at a position on the suction side of a compressor, separates the gas and liquid phases of the refrigerant, and contains the liquid refrigerant. The accumulator comprises: a pressure container ( 2 ) having an inner space (S) formed therein; a refrigerant inlet opening ( 5 ) provided in the pressure container; a refrigerant outlet opening ( 6 ); a conduction pipe ( 8 ) for conducting a refrigerant within the pressure container to the outlet opening; and a gas-liquid separation means ( 15 ) provided with a separation plate ( 16 ) provided within the pressure container so as to face the inlet opening and so as to expand substantially perpendicularly to the direction of the line of flow at the inlet opening. The gas-liquid separation means has, in the region of the separation plate which faces the inlet opening, a mountain-shaped protrusion ( 18 ) having a crest ( 18   a ) and a sloped surface ( 18   b ), the crest ( 18   a ) protruding toward the inlet opening.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an accumulator which is arranged at a suction side of a compressor in a refrigerant circuit, separates the gas and liquid of the refrigerant, and stores the liquid refrigerant. 
       BACKGROUND ART 
       [0002]    As the above-mentioned accumulator, there is known one of a type which arranges a gas-liquid separating plate at the inside and makes the gas/liquid dual phase refrigerant strike it, as shown in for example FIG. 9 of PLT 1.  FIG. 5  is a view which shows an accumulator of FIG. 9 of PLT 1. This accumulator is provided with an inlet  105  and outlet  106  of a fluid which are arranged in parallel at a top part of a pressure vessel  102 , a double wall tube  108  which guides the gas refrigerant to the outlet, and a gas/liquid separating plate (umbrella-shaped member)  115  which spreads out in a substantially conical shape or umbrella shape so as to cover a gas refrigerant inflow port of the double wall tube  108 . The gas/liquid dual phase state refrigerant which flows in from the inlet  105  is separated into a gas and liquid by striking the umbrella shaped member  115  whereby the gaseous refrigerant flows through a circumferential gap S 3  between the umbrella shaped member  115  and the inside surface of the pressure vessel  102 , flows from the top end of the outside tube  110  of the double wall tube to the inside of the double wall tube, descends, then rises inside the inside tube  109  and is sent from the outlet  106  to a compressor (not Shown). The separated liquid refrigerant and oil which had been contained in the refrigerant flow down through the circumferential gap S 3  between the umbrella shaped member and the inside wall of the vessel to be stored at the bottom part of the vessel. 
         [0003]    In this regard, in the accumulator of  FIG. 9 , the flow cross-sectional area changes so as to expand while transitioning from the inflow port  105  to the space S 2  above the umbrella shaped member  115 , then being reduced at the circumferential gap S 3  between the umbrella shaped member  115  and the vessel inside surface, but a relatively large pressure loss of the refrigerant occurred due to this change of the flow cross-sectional area. 
       CITATIONS LIST 
     Patent Literature 
       [0004]    PLT 1. JP 2000-356439 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    The accumulator according to the prior art which is shown in  FIG. 5  sufficiently performs the function demanded and as a result the operation of the compressor can be suitably maintained, but there is the problem that the pressure loss which arises there is relatively large and as a result the refrigeration cycle system falls in efficiency. 
         [0006]    The present invention is made in consideration of the above problem and has as its object the provision of an accumulator for refrigerant use with a small pressure loss. 
       Solution to Problem 
       [0007]    To solve the above problem, the present invention provides an accumulator ( 1 ) arranged at a suction side of a compressor in,a refrigerant circuit, and adapted to separate a refrigerant into a gas and liquid and store the liquid refrigerant, the accumulator ( 1 ) comprising a pressure vessel ( 2 ) which forms an inside space (S), an inflow port ( 5 ) of the refrigerant and an outflow port ( 6 ) of the refrigerant which are provided at the pressure vessel ( 2 ), a conduit ( 8 ) which guides the refrigerant in the pressure vessel ( 2 ) to the outflow port ( 6 ), and a gas-liquid separating means ( 15 ) comprising a separating plate ( 16 ) which is arranged in the pressure vessel ( 2 ) facing the inflow port ( 5 ) and spreads out substantially perpendicular to a flow line at the inflow port ( 5 ), wherein the gas-liquid separating means ( 15 ) has a peak shaped protrusion ( 18 ) which has a single crest ( 18   a ) projecting out in the direction of the inflow port ( 5 ) and a slanted surface ( 18   b ) on the separating plate ( 16 ) at a region facing the inflow port ( 5 ). 
         [0008]    Accordingly, due to the effect of the peak shaped protrusion ( 18 ), the inflow of the refrigerant from the inflow port ( 5 ) can be smoothly converted to the substantially vertical direction and the separating plate ( 16 ) can be arranged in relative proximity to the inflow port ( 5 ) and the change of the flow cross-sectional area becomes smaller, so that the pressure loss of the refrigerant which occurs inside of the accumulator ( 1 ) can be kept small. 
         [0009]    In the present invention, the gas-liquid separating means ( 15 ) has a circumferential wall part ( 17 ) which runs around the separating plate ( 16 ) so as to define a space (S 1 ) which opens at the opposite side to the inflow port ( 5 ) and wherein an inlet ( 11 ) of the conduit ( 8 ) is arranged preferably in the space (S 1 ) defined by the gas-liquid separating means ( 15 ). By virtue of this arrangement, the liquid refrigerant is prevented from entering inside the conduit ( 8 ) from the inlet ( 11 ) of the conduit ( 8 ). 
         [0010]    In the present invention, the peak shaped protrusion ( 18 ) may have the shape of a cone. 
         [0011]    In the present invention, a slanted surface ( 18   b ) of the peak shaped protrusion ( 18 ) is preferably curved in a recessed shape. 
         [0012]    In the present invention, the crest ( 18   a ) of the peak shaped protrusion ( 18 ) may be positioned on the center axis ( 5   x ) of the inflow port ( 5 ). 
         [0013]    In the present invention, the outflow port ( 6 ) may be arranged substantially parallel to the inflow port ( 5 ) and the crest ( 18   a ) of the peak shaped protrusion ( 18 ) may be offset from the center axis ( 5   x ) of the inflow port ( 5 ) in a direction away from the outflow port ( 6 ). By virtue of this arrangement, the conduit ( 8 ) which is connected to the inside of the outflow port ( 6 ) or the ring-shaped protrusion which is formed in the pressure vessel ( 2 ) for connecting the conduit ( 8 ) eases the extent of obstruction to the fluid which enters from the inflow port ( 5 ) and flows along the separating plate ( 16 ). 
         [0014]    In the present invention, an inside surface of the pressure vessel ( 2 ) which faces the separating plate ( 16 ) may extend in parallel to the separating plate ( 16 ) and the gap (g) between the separating plate ( 16 ) and the inside surface of the pressure vessel ( 2 ) may be ¼ times or more of the inside diameter (D) of the inflow port ( 5 ). 
         [0015]    In the present invention, the crest ( 18   a ) of the peak shaped protrusion ( 18 ) may be of a height not more than the boundary surface of the inside space (S) of the pressure vessel ( 2 ) and the inflow port ( 5 ). 
         [0016]    In the present invention, the conduit ( 8 ) is preferably configured as a double wall tube which is comprised of an inside tube ( 9 ) and an outside tube ( 10 ) which surrounds the inside tube ( 9 ), where one end of the inside tube ( 9 ) is connected to the outflow port ( 6 ) and the other end is opened at the inside of the outside tube ( 10 ), and the end of the outside tube ( 10 ) which has an inlet ( 11 ) for introducing a gaseous refrigerant flares out in a trumpet shape. By virtue of this arrangement, it is possible to suppress pressure loss of the gaseous refrigerant at the inlet ( 11 ) of the conduit ( 8 ). 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  is a longitudinal cross-sectional view of an accumulator according to an embodiment of the present invention. 
           [0018]      FIG. 2  is a partial enlarged longitudinal cross-sectional view of a top part of an accumulator of  FIG. 1 . 
           [0019]      FIG. 3  is a further partial enlarged longitudinal cross-sectional view of principal parts of  FIG. 2 . 
           [0020]      FIG. 4  is a partial enlarged longitudinal cross-sectional view of a top part of a modification of an accumulator according to an embodiment of the present invention. 
           [0021]      FIG. 5  is a longitudinal cross-sectional view according to the prior art. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0022]    An accumulator  1  according to an embodiment of the present invention will be explained while referring to the longitudinal cross-sectional view of  FIG. 1  and  FIG. 2 , which is an enlarged view of principal parts of  FIG. 1 . 
         [0023]    The accumulator  1  which is shown in  FIG. 1  is arranged at the suction side of a not shown compressor of an automobile-use refrigeration cycle system. The accumulator  1  comprises a cylindrically shaped pressure vessel  2  which forms an inside space S. The pressure vessel  2  has a deep, closed bottom tube-shaped vessel body  3  with an open top part and an overall substantially disk shaped lid member  4  which closes the open top part of the vessel body  3 . The lid member  4  is joined with the vessel body  3  by welding, whereby the pressure vessel  2  is formed. The lid member  4  is provided with an inflow port  5  and outflow port  6  of a fluid which flows in the up-down direction of  FIG. 1 . At the outside of the inflow port  5 , a feed pipe (not shown) which guides refrigerant from an evaporator is connected. At the outside of the outflow port  6 , a discharge pipe (not shown) which discharges refrigerant to the compressor is connected. The lid member  4  has a ring-shaped projecting part  7  around the outflow port  6  at the inner side. The projecting part  7  is connected to an inside tube  9  of a conduit  8 , which is explained later. 
         [0024]    The accumulator  1  of  FIG. 1  further comprises inside it the conduit  8  which guides refrigerant inside the pressure vessel  2  to the outflow port  6  and a gas-liquid separating means  15  which is provided facing the inflow port  5 . The conduit  8  of the present embodiment is formed as a double wall tube  8  which is comprised of an inside tube  9  and an outside tube  10  which surrounds it. The double wall tube  8  extends vertically downward right under the outflow port  6 . The top end of the inside tube  9  is joined to the outflow port  6  of the lid member  4  of the pressure vessel  2 , while the bottom end opens inside of the outside tube  10 . The outside tube  10  has an inlet  11  at the top end part which flares out in a trumpet shape. The inlet  11  is positioned at a height whereby it is included in the space S 1  which the gas-liquid separating means  15  defines. The bottom end part of the outside tube extends up to close to the bottom of the pressure vessel  2 . The bottom end part of the outside tube  10  is provided with a small oil return hole  12 , but is closed, except for the hole  12 . Furthermore, four fins  13  (in  FIG. 1 , only two shown) are provided extending from the inner circumferential surface of the substantially bottom half of the outside tube  10  toward the center until contiguous with the outer circumferential surface of the inside tube  9 . Through these fins  13 , the outside tube  10  is joined with the inside tube  9 . 
         [0025]    The top end of the inside tube  9  is connected to the outflow port  6  by inserting the top end of the inside tube  9  into the ring-shaped projecting part  7  of the lid member  4 , then enlarging it in diameter. At this time, a recessed part  16   a  which is formed at a later explained separating plate  16  of the gas-liquid separating means  15  is fastened by sandwiching it between the end face of the ring-shaped projecting part  7  of the lid member  4  and the inside tube  9 , so a ring-shaped bead  14  is formed at the inside tube  9  by, for example, beading. 
         [0026]    The gas-liquid separating means  15  of the present embodiment has a separating plate  16  which spreads out substantially horizontally, as shown in  FIG. 1 , in other words, substantially perpendicular to the direction of the flow lines at the inflow port  5 , and a circumferential wall part  17  which extends downward from the outer circumferential part of the separating plate  16 . The gas-liquid separating means  15  is formed with a space S 1  which opens at the opposite side to the inflow port  5  by the separating plate  16  and the circumferential wall part  17 . Inside of this space S 1 , as explained above, an inlet  11  of an outside tube  10  of the conduit  8  is opened. The gas-liquid separating means  15  has an integrally formed peak shaped protrusion  18  which has one crest  18   a  which protrudes the direction of the inflow port  5  and slanted surfaces  18   b  at the region of the separating plate  16  which faces the inflow port  5 . The peak shaped protrusion  18 , as shown by the further partial enlarged view of  FIG. 2  constituted by  FIG. 3 , is shaped similar to a cone which has a round bottom surface in the present embodiment, but the slanted surface  18   b  is curved in a recessed shape and therefore the shape is different from a conical shape. The crest  18   a  of the protrusion  18  is arranged on the center axis  5   x  of the inflow port  5  in the present embodiment. The tip of the crest reaches exactly the inside open surface of the inflow port  5 , i.e. the boundary surface between the inside space S of the pressure vessel  2 , and more particularly, the later explained upper separating plate space S 2 , and the inflow port  5 . 
         [0027]    The inside surface of the lid member  4  of the pressure vessel  2  extends flat and horizontally, except at the ring-shaped projecting part  7  at the inside of the outflow port  6 . As a result, with the separating plate  16  of the gas-liquid separating means  15 , a space S 2  which has a substantially uniform height “g”, except at the region of the peak shaped protrusion  18  is formed. It should be noted that the space S 2  will hereinafter be referred to as an “upper separating plate space S 2 ”. In the accumulator shown in  FIGS. 1 to 3 , the gas-liquid separating means  15  is arranged so that the height “g” of the upper separating plate space S 2  becomes ¼ of the inside diameter D of the inflow port  5 . In the structure of this embodiment of the present invention, the height “g” of the upper separating plate space S 2 , i.e. the gap “g” between the separating plate  16  and the inside surface of the lid member  4 , differs in optimal value, depending on the conditions of the flow rate of the inflowing refrigerant and the size of a gap S 3  between the circumferential wall part  17  of the gas-liquid separating means  15  and the inner circumferential surface of the pressure vessel (referred to below as a “circumferential wall gap S 3 ”) etc., but in general ¼ to 1 time the inside diameter D of the inflow port  5  is preferable. 
         [0028]    The “inside diameter D of the inflow port” in the terms in this Description means the inside diameter D of the flow channel at the inflow side contiguous with the inside space S of the pressure vessel  2 . As a result, in the case of the embodiment which is shown in  FIGS. 1 to 3 , “the inside diameter D of the inflow port” matches the inside diameter D of the inside open surface of the inflow port  5  which is formed in the lid member  4 . However, in another not shown embodiment, when the tip of the feed pipe from the evaporator is inserted up to the inside end face of the lid member  4 , the inside diameter of the tip part of the feed pipe becomes the “inside diameter of the inflow port”. 
         [0029]    Next, how an accumulator  1  of the embodiment of  FIG. 1  operates will be explained. 
         [0030]    The gas/liquid dual phase refrigerant which is discharged from the evaporator (not shown) is introduced from the inflow port  5  of the accumulator  1  substantially vertically downward such as shown by the arrow in  FIG. 2 , and strikes the separating plate  16  of the substantially horizontally arranged gas-liquid separating means  15 . As a result, the large mass liquid phase refrigerant and the oil which is contained in the refrigerant deposit on the front surface of the gas-liquid separating means  15  and the inside surface of the pressure vessel  2 , drip downward from there, and are stored in the vessel  2 . On the other hand, the gaseous refrigerant passes through the circumferential wall part gap S 3 , flows from the inlet  11  at the top end part of the outside tube  10  to the inside of the double wall tube  8 , rises from the opening at the bottom end of the inside tube  9  through the inside of the inside tube  9  to reach the outflow port  6 , and is discharged to the compressor (not shown). 
         [0031]    In the accumulator  1  of the present embodiment, the liquid refrigerant which is stored close to the bottom part of the pressure vessel  2  and contains a large amount of oil is also sucked into the double wall tube  8  through the small oil return hole  12  which is provided at the bottom part of the outside tube  10  and returned to the compressor together with the gaseous refrigerant. 
         [0032]    In the accumulator  1  of the present embodiment, the refrigerant which flows in from the inflow port  5  is smoothly converted in flow from a vertical to a horizontal direction by the action of the peak shaped protrusion  18  which is provided on that separating plate  16  facing the inflow port  5 , so that pressure loss is reduced compared with when there is no peak shaped protrusion  18 . Furthermore, since the height “g” of the upper separating plate space S 2  is set to relatively less in the present embodiment, i.e. to ¼ of the inside diameter D of the inflow port  5 , the change in cross-sectional area of the flow is smaller. More specifically, the rate of increase of the flow cross-sectional area of the upper separating plate space S 2  to the flow cross-sectional area of the inflow port  5  and the rate of decrease of the flow cross-sectional area of the circumferential wall part gap S 3  to the flow cross-sectional area of the upper separating plate space S 2  is relatively smaller, and thus pressure loss of the refrigerant gas is kept small. 
         [0033]    Further, the inlet  11  of the double wall tube  8  into which the separated gas refrigerant flows flares out in a trumpet shape, whereby pressure loss at this part is also kept small. 
       Other Embodiments 
       [0034]    While the peak shaped protrusion  18  is shaped similar to a conical shape having a circular bottom in the above embodiment, and thus the slanted surface  18   b  is shaped curved in a recessed shape, an embodiment wherein the peak shaped protrusion  18  is a conical shape or a prismatic shape which has a straight slanted surface or surfaces  18   b  (not shown) is also possible. 
         [0035]    In the peak shaped protrusion  18  of the above embodiment, the tip of the crest  18   a  reaches exactly the inside open surface of the inflow port  5 . However, the optimal value of the height of the peak shaped protrusion  18  differs, for example, depending on the height “g” of the upper separating plate space S 2  as well. Therefore, the pressure loss sometimes falls more in an embodiment wherein the height is lower than that of the embodiment of  FIG. 3  and the tip does not reach the open surface (not shown). 
         [0036]    Since the outflow port  6  must be joined with the inside tube  9 , the ring-shaped projecting part  7  is formed at the inside of the lid member  4 . However, the ring-shaped projecting part  7  becomes an obstruction to the fluid which flows in from the inflow port  5  and flows toward the circumferential wall part  17 . For this reason, to ease the effects of this obstacle and therefore the pressure loss, an embodiment is also possible wherein the horizontal direction position of the crest  18   a  of the peak shaped protrusion  18 , as shown in  FIG. 5 , is offset by a distance “e” from the center axis  5   x  of the inflow port  5  in a direction away from the outflow port  6 . It should be noted that while not shown, a structure wherein the inside tube  9  is joined with the outflow port  6  without forming the ring-shaped projecting part  7  at the inside of the lid member  4  is also easily possible, although in such a case, the inside tube  9  itself becomes an obstruction to the flow of the gaseous refrigerant. 
         [0037]    In the embodiment of  FIGS. 1 to 3 , the peak shaped protrusion  18  is formed integrally with the separating plate  16 . However, an embodiment wherein the peak shaped protrusion is a member separate from the separating plate and is comprised of a member which is attached to the separating plate by, for example, screws or other fastening means (not shown) is also possible. 
         [0038]    The gas-liquid separating means  15  of the above embodiment has a circumferential wall part  17 . However, an embodiment wherein the gas-liquid separating means  15  does not have a circumferential wall part  17  (not shown) is also possible. 
         [0039]    The conduit  8  in the above embodiment is comprised of a double wall tube. However, an embodiment wherein the conduit  8  is a tubular structure other than a double wall tube, for example, wherein it is comprised of a single U-shaped tube which is bent in a U-shape, has one end connected to the outflow port  6 , and has the other end opened inside of the inside space S of the pressure vessel  2  (not shown) is also possible. 
         [0040]    While the present invention is explained in detail based on specific embodiments, it should be apparent that a person skilled in the art could make various changes, corrections, etc. without departing from the scope of the claims and overall concept of the present invention. 
       Reference Signs List 
       [0041]      1  accumulator 
         [0042]      2  pressure vessel 
         [0043]      3  vessel body 
         [0044]      4  lid member 
         [0045]      5  inflow port 
         [0046]      6  outflow port 
         [0047]      8  conduit 
         [0048]      9  inside tube 
         [0049]      10  outside tube 
         [0050]      11  inlet 
         [0051]      15  gas-liquid separating means 
         [0052]      16  separating plate 
         [0053]      17  circumferential wall part 
         [0054]      18  peak shaped protrusion