Patent Publication Number: US-10330356-B2

Title: Liquid receiver and condenser using the same

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a liquid receiver used in a car air conditioner which is a refrigeration cycle mounted on, for example, an automobile. The liquid receiver separates gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant. The present invention also relates to a condenser in which such a liquid receiver is used. 
     Herein, the term “liquid-phase refrigerant” encompasses liquid-phase predominant mixed-phase refrigerant containing a small amount of gas-phase refrigerant. 
     There has been known a condenser of a car air conditioner which includes a condensation section, a supercooling section provided below the condensation section, and a liquid receiver provided between the condensation section and the supercooling section. The liquid receiver is composed of a tubular body whose longitudinal direction coincides with the vertical direction and which is closed at the upper and lower ends thereof. Refrigerant flowing out of the condensation section flows into the supercooling section through the liquid receiver. Specifically, gas-liquid-mixed-phase refrigerant flowing out of the condensation section into the liquid receiver is separated into gas-phase refrigerant and liquid-phase refrigerant in the liquid receiver, and the liquid-phase refrigerant flows into the supercooling section. 
     A liquid receiver for use in a condenser of the above-described type has been proposed (see Japanese Patent Application Laid-Open (kokai) No. 2015-28394). The proposed liquid receiver includes a tubular female screw forming portion whose axial direction coincides with the vertical direction and which has a female screw formed on an upper portion of the inner circumferential surface thereof; a tubular body portion whose lower end portion is joined to the female screw forming portion such that the longitudinal direction of the body portion coincides with the vertical direction and which is closed at the upper end and is open at the lower end; and a columnar cap which is inserted into the female screw forming portion, which has a male screw for threading engagement with the female screw. The female screw forming portion has an insertion portion which is inserted into the body portion and is joined to the inner circumferential surface of the body portion and an uninserted portion disposed outside the body portion. The female screw is provided on the uninserted portion, the body portion has a refrigerant inflow hole through which refrigerant flows from the condensation section of the condenser into the body portion, and the female screw forming portion has a refrigerant outflow hole through which refrigerant flows out to the supercooling section of the condenser. A seal means is provided so as to establish sealing between a region of the inner circumferential surface of the female screw forming portion, which region is located below the female screw, and a region of the outer circumferential surface of the cap, which region is located below the male screw. 
     However, the liquid receiver disclosed in the publication has the following problem. Specifically, the refrigerant inflow hole through which refrigerant flows from the condensation section of the condenser into the body portion is formed in the body portion, and the refrigerant outflow hole through which refrigerant flows out to the supercooling section of the condenser is formed in the female screw forming portion, so that the distance in the vertical direction from the lower end of the liquid receiver to the upper end of the refrigerant inflow hole is relatively long. Therefore, when a refrigerating cycle which includes a condenser having such a liquid receiver is charged with refrigerant, a relatively long time is needed to fill a portion of the internal space of the liquid receiver located below the refrigerant inflow hole with liquid-phase refrigerant. In addition, in the case where the amount of refrigerant charge is constant, the width of a stable range within which the degree of supercooling becomes constant becomes relatively narrow. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problem, an object of the present invention is to provide a liquid receiver which allows a refrigerating cycle to be charged with a proper amount of refrigerant in an early stage and which can widen a stable region within which the degree of supercooling is constant. Another object of the present invention is to provide a condenser in which the liquid receiver is used. 
     A liquid receiver according to the present invention is adapted to receive gas-liquid-mixed-phase refrigerant flowing from a condensation section of a condenser and separate the gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant. The liquid receiver comprises a base member joined to a tubular header tank of a condenser, a tank member, and a plug. The base member has a tubular shape, has a longitudinal direction, and is open at a first end on one side in the longitudinal direction and at a second end on the other side in the longitudinal direction. The tank member has a tubular shape, has a longitudinal direction coinciding with the longitudinal direction of the base member, is open at a first end on one side in the longitudinal direction of the tank member, and is closed at a second end on the other side in the longitudinal direction of the tank member. The first end of the tank member is fixed to the second end of the base member. The plug has a longitudinal direction coinciding with the longitudinal direction of the base member and is removably fitted into the base member from the first end side of the base member. The plug has a first end on the first end side of the base member and a second end on the second end side of the base member. A female screw is provided in a region of an inner circumferential surface of the base member, the region being located between the first end and the second end of the base member. A refrigerant inflow hole and a refrigerant outflow hole are formed in a portion of the base member, which portion is located on the second end side with respect to the female screw, to be separated from each other such that the refrigerant inflow hole is located on the second end side and the refrigerant outflow hole is located on the first end side. A male screw is provided in a longitudinally intermediate region of an outer circumferential surface of the plug to be located on the first end side with respect to the refrigerant outflow hole. The male screw is screwed into the female screw of the base member. At a portion of the base member on the first end side with respect to the female screw, a seal member is provided so as to establish sealing between the inner circumferential surface of the base member and the outer circumferential surface of the plug. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view specifically showing the overall structure of a condenser in which a liquid receiver of the present invention is used; 
         FIG. 2  is a front view schematically showing the condenser of  FIG. 1 ; 
         FIG. 3  is a partially cutaway vertical sectional view showing, on an enlarged scale, a left header tank and a liquid receiver of the condenser of  FIG. 1  from the front side; and 
         FIG. 4  is a partially cutaway exploded view showing the left header tank and the liquid receiver of the condenser of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will next be described with reference to the drawings. 
     In the following description, the upper side, lower side, left-hand side, and right-hand side of  FIG. 1  will be referred to as “upper,” “lower,” “left,” and “right,” respectively. 
     In the following description, the term “aluminum” encompasses aluminum alloys in addition to pure aluminum. 
       FIG. 1  specifically shows the overall structure of a condenser in which a liquid receiver of the present invention is used.  FIG. 2  schematically shows the condenser of  FIG. 1 .  FIGS. 3 and 4  show the structure of a main portion of the condenser of  FIG. 1 . In  FIG. 2 , individual heat exchange tubes are not illustrated, and corrugate fins, side plates, a refrigerant inlet member, and a refrigerant outlet member are also not illustrated. 
     In  FIGS. 1 and 2 , a condenser  1  is composed of a condensation section  2 ; a supercooling section  3  provided below the condensation section  2 ; and a tank-like liquid receiver  4  which is formed of aluminum and is provided between the condensation section  2  and the supercooling section  3  such that the longitudinal direction of the liquid receiver  4  coincides with the vertical direction. The liquid receiver  4  separates gas-liquid-mixed-phase refrigerant produced as a result of condensation at the condensation section  2  into gas-phase refrigerant and liquid-phase refrigerant, stores the liquid-phase refrigerant, and supplies the liquid-phase refrigerant to the supercooling section  3 . The condenser  1  constitutes a refrigeration cycle in cooperation with a compressor, an expansion valve (pressure reducer), and an evaporator; and the refrigeration cycle is mounted on a vehicle as a car air conditioner. 
     The condenser  1  includes a plurality of flat heat exchange tubes  5  formed of aluminum, two header tanks  6  and  7  formed of aluminum, corrugate fins  8  formed of aluminum, and side plates  9  formed of aluminum. The heat exchange tubes  5  are disposed such that their width direction coincides with an air-passing direction, their longitudinal direction coincides with the left-right direction, and they are spaced from one another in the vertical direction. The header tanks  6  and  7  are disposed such that their longitudinal direction coincides with the vertical direction and they are spaced from each other in the left-right direction, and left and right end portions of the heat exchange tubes  5  are connected to the header tanks  6  and  7 . Each of the corrugate fins  8  is disposed between and brazed to adjacent heat exchange tubes  5 , or is disposed on the outer side of the uppermost or lowermost heat exchange tube  5  and joined to the corresponding heat exchange tube  5  through use of a brazing material. The side plates  9  are disposed on the corresponding outer sides of the uppermost and lowermost corrugate fins  8 , and are joined to these corrugate fins  8  through use of a brazing material. In the following description, joining through use of a brazing material will also referred to as “brazing.” 
     Each of the condensation section  2  and the supercooling section  3  of the condenser  1  includes at least one heat exchange path (in the present embodiment, one heat exchange path P 1 , P 2 ) formed by a plurality of heat exchange tubes  5  successively arranged in the vertical direction. The heat exchange path P 1  provided in the condensation section  2  serves as a refrigerant condensation path. The heat exchange path P 2  provided in the supercooling section  3  serves as a refrigerant supercooling path. The flow direction of refrigerant is the same among all the heat exchange tubes  5  which form each heat exchange path P 1 , P 2 . The flow direction of refrigerant in the heat exchange tubes  5  which form a certain heat exchange path is opposite the flow direction of refrigerant in the heat exchange tubes  5  which form another heat exchange path adjacent to the certain heat exchange path. The heat exchange path P 1  of the condensation section  2  will be referred to as the first heat exchange path, and the heat exchange path P 2  of the supercooling section  3  will be referred to as the second heat exchange path. In the present embodiment, one heat exchange path is provided in each of the condensation section  2  and the supercooling section  3 ; however, the number of heat exchange paths is not limited thereto and may be changed freely, provided that the downstream (in the refrigerant flow direction) ends of the heat exchange tubes  5  of the heat exchange path located furthest downstream in the refrigerant flow direction in the condensation section  2  and the upstream (in the refrigerant flow direction) ends of the heat exchange tubes  5  of the heat exchange path located furthest upstream in the refrigerant flow direction in the supercooling section  3  are located on the same side; i.e., are located on the left side or the right side. In the present embodiment, since the single heat exchange path P 1  is provided in the condensation section  2 , the first heat exchange path P 1  serves as a heat exchange path located furthest upstream in the refrigerant flow direction in the condensation section  2  and also serves as a heat exchange path located furthest downstream in the refrigerant flow direction in the condensation section  2 . Similarly, since the single heat exchange path P 2  is provided in the supercooling section  3 , the second heat exchange path P 2  serves as a heat exchange path located furthest upstream in the refrigerant flow direction in the supercooling section  3  and also serves as a heat exchange path located furthest downstream in the refrigerant flow direction in the supercooling section  3 . 
     The header tanks  6  and  7  have respective partition members  11  which are formed of aluminum and are provided at the same vertical position on the lower side between the first heat exchange path P 1  and the second heat exchange path P 2  so as to divide the interior spaces of the header tanks  6  and  7  into upper and lower spaces. A portion of the condenser  1  located on the upper side of the two partition members  11  is the condensation section  2 , and a portion of the condenser  1  located on the lower side of the two partition members  11  is the supercooling section  3 . 
     The right header tank  6  has a refrigerant inlet  12  formed in a portion of the circumferential wall thereof located above the corresponding partition member  11 , and gas-phase refrigerant compressed by the compressor flows into the refrigerant inlet  12 . The right header tank  6  has a refrigerant outlet  13  formed in a portion of the circumferential wall thereof located below the corresponding partition member  11 , and liquid-phase refrigerant flows out through the refrigerant outlet  13  toward the expansion valve. A refrigerant inlet member  14  formed of aluminum and having an internal passage communicating with the refrigerant inlet  12  and a refrigerant outlet member  15  formed of aluminum and having an internal passage communicating with the refrigerant outlet  13  are brazed to the right header tank  6 . The left header tank  7  has a refrigerant outlet  16  formed in a portion of the circumferential wall thereof located above the corresponding partition member  11 , and gas-liquid-mixed-phase refrigerant flows into the liquid receiver  4  through the refrigerant outlet  16 . The left header tank  7  has a refrigerant inlet  17  formed in a portion of the circumferential wall thereof located below the corresponding partition member  11 , and liquid-phase refrigerant flows into the supercooling section  3  through the refrigerant inlet  17 . Therefore, the space of the right header tank  6  located above the corresponding partition member  11  serves as a condensation section inlet header  18 , the space of the left header tank  7  located above the corresponding partition member  11  serves as a condensation section outlet header  19 , the space of the left header tank  7  located below the corresponding partition member  11  serves as a supercooling section inlet header  21 , and the space of the right header tank  6  located below the corresponding partition member  11  serves as a supercooling section outlet header  22 . 
     As shown in  FIGS. 3 and 4 , the liquid receiver  4  is composed of a base member  23  whose longitudinal direction coincides with the vertical direction and which is brazed to the left header tank  7 ; a tank member  24  whose longitudinal direction coincides with the vertical direction and which is fixed to the base member  23 ; and a plug  25  whose longitudinal direction coincides with the vertical direction and which is removably attached to the base member  23 . The base member  23  is a cylindrical tubular member which is open at its lower end (first longitudinal end) and at its upper end (second longitudinal end). The tank member  24  is a cylindrical tubular member which is open at its lower end (first longitudinal end) and is closed at its upper end (second longitudinal end). The lower end of the tank member  24  is fixed to the upper end of the base member  23 , and the internal space of the tank member  24  communicates with the internal space of the base member  23 . The plug  25  is removably inserted into the base member  23  from the lower end side of the base member  23 . The lower end (first longitudinal end) of the plug  25  is located near the lower end of the base member  23 , and the upper end (second longitudinal end) of the plug  25  is located between the upper and lower ends of the base member  23 . 
     The base member  23  is formed of aluminum bare material such as aluminum extrudate. The base member  23  has a female screw  26  which is formed in a vertically intermediate region of the inner circumferential surface thereof (in the present embodiment, in a region of the inner circumferential surface located slightly below the center thereof in the vertical direction). In a portion of the base member  23  located above the female screw  26 , a refrigerant inflow hole  27  communicating with the refrigerant outlet  16  of the condensation section outlet header  19  and a refrigerant outflow hole  28  communicating with the refrigerant inlet  17  of the supercooling section inlet header  21  are formed at a predetermined interval in the vertical direction such that the refrigerant inflow hole  27  is located above the refrigerant outflow hole  28 . 
     The base member  23  has an elongated protrusion  29  integrally formed on its outer circumferential surface so as to extend partially in the circumferential direction and extend over the entire length of the base member  23  in the vertical direction. The elongated protrusion  29  protrudes radially outward, and its protrusion end has a flat surface. Fixing lugs  31  and  32  are integrally provided on the protrusion  29  at vertical positions corresponding to the refrigerant inflow hole  27  and the refrigerant outflow hole  28 . The fixing lugs  31  and  32  have arcuate close contact surfaces which come into close contact with the outer surface of the left header tank  7  of the condenser  1 . The opposite ends of the refrigerant inflow hole  27  are open to the inner circumferential surface of the base member  23  and the close contact surface of the upper fixing lug  31 , and the opposite ends of the refrigerant outflow hole  28  are open to the inner circumferential surface of the base member  23  and the close contact surface of the lower fixing lug  32 . The outlines of the cross sections of portions of the base member  23  where the two fixing lugs  31  and  32  are provided have the same shape. The upper fixing lug  31  is brazed to the outer surface of the left header tank  7  such that the refrigerant inflow hole  27  coincides with the refrigerant outlet  16  of the condensation section outlet header  19 , and the lower fixing lug  32  is brazed to the outer surface of the left header tank  7  such that the refrigerant outflow hole  28  coincides with the refrigerant inlet  17  of the supercooling section inlet header  21 . 
     A cylindrical tubular insertion portion  33  having a reduced diameter is provided at the upper end of the base member  23  via a step portion  34 . Further, a cylindrical lower seal surface  35  whose diameter is larger than the root diameter of the female screw  26  is provided in a region of the inner circumferential surface of the base member  23 , which region is located below the female screw  26 , and a cylindrical upper seal surface  36  whose diameter is smaller than the inner diameter of the female screw  26  is provided in another region of the inner circumferential surface of the base member  23 , which region is located above the female screw  26 . The base member  23  is formed by performing cutting and threading on an extrudate having the same shape as the outline of the cross section of the portions where the two fixing lugs  31  and  32  are provided. 
     The tank member  24  is composed of a cylindrical body  37  which is formed of aluminum bare material such as aluminum extrudate, whose longitudinal direction coincides with the vertical direction, and which is open at its upper and lower ends; and a closing member  38  which is formed of an aluminum brazing sheet having brazing material layers on opposite sides thereof and which is brazed to the upper end of the cylindrical body  37  so as to close the upper end opening. 
     The cylindrical body  37  of the tank member  24  has an elongated protrusion  39  integrally formed on the outer circumferential surface of the cylindrical body  37  so as to extend partially in the circumferential direction and extend over the entire length of the cylindrical body  37  in the vertical direction. The elongated protrusion  39  protrudes radially outward, and its protrusion end has a flat surface. A spacer portion  41  is integrally provided at the upper end of the elongated protrusion  39 . The spacer portion  41  has an arcuate close contact surface which comes into close contact with the outer surface of the left header tank  7  of the condenser  1 . The outline of the cross section of a portion of the cylindrical body  37  where the spacer portion  41  is not provided has the same shape as the outline of the cross section of a portion of the base member  23  where the two fixing lugs  31  and  32  are not provided. Also, the outline of the cross section of the portion of the cylindrical body  37  where the spacer portion  41  is provided has the same shape as the outline of the cross section of the portions of the base member  23  where the two fixing lugs  31  and  32  are provided. The inner diameter of the cylindrical body  37  is larger than the outer diameter of the insertion portion  33  of the base member  23 . The spacer portion  41  is brazed to the outer surface of the left header tank  7 . The cylindrical body  37  is formed by performing cutting on an extrudate having the same shape as the outline of the cross section of the portion of the cylindrical body  37  where the spacer portion  41  is provided. 
     The closing member  38  of the tank member  24  is formed by performing press working on an aluminum brazing sheet and has a fitting portion  42  which is fitted into the cylindrical body  37  and an outward flange  43  integrally provided at the upper end of the circumferential wall of the fitting portion  42 . The circumferential wall of the fitting portion  42  serves as a contact portion which comes into contact with the inner circumferential surface of the cylindrical body  37  and is brazed to the inner circumferential surface of the cylindrical body  37 . The outward flange  43  serves as a contact portion which comes into contact with the upper end surface of the cylindrical body  37  and is brazed to the upper end surface of the cylindrical body  37 . 
     The base member  23  and the cylindrical body  37  of the tank member  24  are joined together with a connection ring  44  intervening therebetween. The connection ring  44  is formed by performing press working on an aluminum brazing sheet and has a short cylindrical portion  45  which is present between the outer circumferential surface of the insertion portion  33  of the base member  23  and the inner circumferential surface of the cylindrical body  37  and an outward flange  46  which is integrally provided at the lower end of the short cylindrical portion  45  and is present between the step portion  34  of the base member  23  and the lower end surface of the cylindrical body  37 . The short cylindrical portion  45  of the connection ring  44  is brazed to the outer circumferential surface of the insertion portion  33  of the base member  23  and the inner circumferential surface of the cylindrical body  37 , and the outward flange  46  is brazed to the step portion  34  of the base member  23  and the lower end surface of the cylindrical body  37 , whereby the base member  23  and the cylindrical body  37  of the tank member  24  are joined together with the connection ring  44  intervening therebetween. 
     The plug  25  is formed of a synthetic resin and has a circular columnar shape. The plug  25  has a male screw  47  formed in a vertically intermediate region of the cylindrical outer circumferential surface of the plug  25  to be located below the refrigerant outflow hole  28 . The male screw  47  is brought into screw engagement with the female screw  26  of the base member  23 , whereby the plug  25  is removably fitted into the base member  23 . The upper end of the plug  25  is located at a vertical position between the refrigerant inflow hole  27  and the refrigerant outflow hole  28 . The plug  25  has a bottomed tool hole  48  which extends upward from the lower end surface of the plug  25  and into which a tool for rotating the plug  25  is inserted. 
     The plug  25  has a bottomed hole  49  which extends downward from the upper end surface thereof and whose lower end is located below the refrigerant outflow hole  28 . The plug  25  has a plurality of communication holes  51  which are formed in the circumferential wall of the bottomed hole  49  at predetermined intervals in the circumferential direction, and a filter  52  for removing foreign substances is fixed to the plug  25  such that the filter  52  covers the communication holes  51 . At least a portion of each communication hole  51  in the vertical direction is located within the range of the refrigerant outflow hole  28  in the vertical direction. One annular O-ring groove  53  is formed in a region of the outer circumferential surface of the plug  25 , which region is located above the communication holes  51 , and an O-ring  54  (seal member) fitted into the O-ring groove  53  establishes sealing between the upper seal surface  36  of the base member  23  and the outer circumferential surface of the plug  25 . Further, two annular O-ring grooves  55  are formed in a region of the outer circumferential surface of the plug  25 , which region is located below the male screw  47 , such that the two annular O-ring grooves  55  are spaced from each other in the vertical direction, and O-rings  56  (seal members) fitted into the O-ring groove  55  establish sealing between the lower seal surface  35  of the base member  23  and the outer circumferential surface of the plug  25 . 
     Although not illustrated, a desiccant bag is disposed in a region of the interior of the liquid receiver, which region is located above the plug  25 , such that the longitudinal direction of the desiccant bag coincides with the vertical direction. The desiccant bag has gas permeability and liquid permeability and which stores a desiccant. 
     In a car air conditioner including the condenser  1  having the above-described structure, gas-phase refrigerant of high temperature and high pressure compressed by the compressor flows into the condensation section inlet header  18  of the right header tank  6  through the refrigerant inlet member  14  and the refrigerant inlet  12 . The refrigerant is condensed while flowing leftward within the heat exchange tubes  5  of the first heat exchange path P 1  and flows into the condensation section outlet header  19  of the left header tank  7 . The refrigerant having flowed into the condensation section outlet header  19  of the left header tank  7  passes through the header side refrigerant outlet  16  and the refrigerant inflow hole  27  and enters the liquid receiver  4 . 
     Since the refrigerant having flowed into the liquid receiver  4  is gas-liquid-mixed-phase refrigerant, liquid-phase refrigerant which is a portion of the gas-liquid-mixed-phase refrigerant accumulates in a lower portion of the interior space of the liquid receiver  4  due to the gravitational force, and gas-phase refrigerant which is a portion of the gas-liquid-mixed-phase refrigerant accumulates in an upper portion of the interior space of the liquid receiver  4 . The liquid-phase refrigerant enters the bottomed hole  49  of the plug  25 , passes through the filter  52 , and enters the supercooling section inlet header  21  of the left header tank  7  through the refrigerant outflow hole  28  and the refrigerant inlet  17 . 
     The refrigerant having entered the supercooling section inlet header  21  of the left header tank  7  is super-cooled while flowing rightward within the heat exchange tubes  5  of the second heat exchange path P 2 , and enters the supercooling section outlet header  22  of the right header tank  6 . Subsequently, the super-cooled refrigerant flows out through the refrigerant outlet  13  and the refrigerant outlet member  15 , and is then fed to the evaporator through the expansion valve. 
     When the car air conditioner using the above-described condenser is charged with refrigerant, a portion of the internal space of the liquid receiver  4 , which portion is located below the refrigerant inflow hole  27 , is filled with liquid-phase refrigerant within a relatively short period of time. As a result, in an early stage, the refrigerant charge amount of the refrigerating cycle can reach a proper charge amount at which the degree of supercooling becomes constant. In addition, the internal volume of a portion of the internal space of the liquid receiver  4 , which portion is located above the refrigerant inflow hole  27 , is relatively large. Therefore, the width of a stable range within which the degree of supercooling becomes constant; i.e., the width of the range of the refrigerant charge amount within which the degree of supercooling becomes constant, increases. As a result, supercooling characteristics which are more stable against load fluctuation and leakage of refrigerant are obtained. 
     The present invention comprises the following modes. 
     1) A liquid receiver for receiving gas-liquid-mixed-phase refrigerant flowing from a condensation section of a condenser and separating the gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant, comprising: 
     a tubular base member which has a longitudinal direction, which is open at a first end on one side in the longitudinal direction and at a second end on the other side in the longitudinal direction, and which is joined to a header tank of the condenser; 
     a tubular tank member which has a longitudinal direction coinciding with the longitudinal direction of the base member, which is open at a first end on one side in the longitudinal direction of the tank member and is closed at a second end on the other side in the longitudinal direction of the tank member, and whose first end is fixed to the second end of the base member; 
     a plug which has a longitudinal direction coinciding with the longitudinal direction of the base member, which is removably fitted into the base member from the first end side of the base member, and which has a first end on the first end side of the base member and a second end on the second end side of the base member, wherein a female screw is provided in a region of an inner circumferential surface of the base member, the region being located between the first end and the second end of the base member; 
     a refrigerant inflow hole and a refrigerant outflow hole are formed in a portion of the base member, which portion is located on the second end side with respect to the female screw, to be separated from each other such that the refrigerant inflow hole is located on the second end side and the refrigerant outflow hole is located on the first end side; 
     a male screw is provided in a longitudinally intermediate region of an outer circumferential surface of the plug to be located on the first end side with respect to the refrigerant outflow hole; 
     the male screw is screwed into the female screw of the base member; and 
     at a portion of the base member on the first end side with respect to the female screw, a seal member is provided so as to establish sealing between the inner circumferential surface of the base member and the outer circumferential surface of the plug. 
     2) The liquid receiver described in par. 1), wherein a distance between the first end of the base member and an end of the refrigerant inflow hole on the second end side of the base member is less than 60 mm. 
     3) The liquid receiver described in par. 1), wherein the second end of the plug is located between the refrigerant inflow hole and the refrigerant outflow hole; the plug has a bottomed hole which extends from its end surface on the second end side toward the first end side and whose bottom is located on the first end side with respect to the refrigerant outflow hole; a communication hole is formed in a circumferential wall of the bottomed hole of the plug; a filter for removing foreign substances is fixed to the plug such that the filter covers the communication hole; and a seal member for establishing sealing is provided between a region of the inner circumferential surface of the base member between the refrigerant inflow hole and the refrigerant outflow hole and a region of the outer circumferential surface of the plug, which region is located on the second end side with respect to the communication hole. 
     4) The liquid receiver described in par. 1), wherein the base member has a cylindrical tubular shape; a protrusion protruding radially outward is provided on the outer circumferential surface of the base member such that the protrusion extends in a portion of the outer circumferential surface in a circumferential direction and extends over the entire length of the base member in the longitudinal direction; fixing lugs having arcuate close contact surfaces which come into close contact with an outer surface of the header tank of the condenser are provided on the protrusion at positions corresponding to the refrigerant inflow hole and the refrigerant outflow hole; and opposite ends of the refrigerant inflow hole and the refrigerant outflow hole are open to the inner circumferential surface of the base member and the close contact surfaces of the fixing lugs, respectively, 
     wherein the tank member is composed of a cylindrical body which is open at the first end and the second end, and a closing member which is joined to the second end of the cylindrical body and which closes an opening of the cylindrical body on the second end side; and a protrusion protruding radially outward is provided on the outer circumferential surface of the cylindrical body such that the protrusion extends in a portion of the outer circumferential surface in a circumferential direction and extends over the entire length of the cylindrical body in the longitudinal direction, 
     wherein a cross section of a portion of the base member where the fixing lugs are not provided has the same outline as a cross section of the cylindrical body of the tank member. 
     5) The liquid receiver described in par. 4), wherein the base member is formed of a bare material; a cylindrical tubular insertion portion whose outer diameter is smaller than an inner diameter of the cylindrical body of the tank member and which is inserted into the cylindrical body is provided at the second end of the base member with a step portion intervening therebetween; and a connection ring is disposed between the base member and the cylindrical body of the tank member, the connection ring having a short cylindrical portion which is present between an outer circumferential surface of the insertion portion of the base member and an inner circumferential surface of the cylindrical body, and an outward flange which is integrally provided at an end of the short cylindrical portion on the side toward the first end of the tank member and is present between the step portion of the base member and an end surface of the cylindrical body; and the short cylindrical portion and the outward flange of the connection ring are joined to the base member and the cylindrical body through use of a brazing material. 
     6) The liquid receiver described in par. 4), wherein a spacer portion having an arcuate close contact surface which comes into close contact with an outer surface of the header tank of the condenser to which the base member is joined is provided at an end of the protrusion of the cylindrical body of the tank member, the end being located on the second end side of the tank member; and a cross section of a portion of the cylindrical body of the tank member where the spacer portion is provided has the same outline as a cross section of a portion of the base member where the fixing lugs are provided. 
     7) A condenser comprising a condensation section; a supercooling section provided below the condensation section; and a liquid receiver which is provided between the condensation section and the supercooling section and which receives gas-liquid-mixed-phase refrigerant from the condensation section and separates the gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant, 
     wherein the condensation section includes a condensation section outlet header whose longitudinal direction coincides with a vertical direction, and a heat exchange path formed by a plurality of heat exchange tubes which are disposed in parallel such that their longitudinal direction coincides with a left-right direction and they are spaced from one another in the vertical direction and each of which is connected, at one end in the longitudinal direction, to the condensation section outlet header; the supercooling section includes a supercooling section inlet header disposed on the lower side and adjacent to the condensation section outlet header, and a heat exchange path formed by a plurality of heat exchange tubes which are disposed in parallel such that their longitudinal direction coincides with the left-right direction and they are spaced from one another in the vertical direction and each of which is connected, at one end in the longitudinal direction, to the supercooling section inlet header; and the liquid receiver is composed of the liquid receiver described in par. 1),
         wherein the condensation section outlet header and the supercooling section inlet header are provided in a single header tank; the condensation section outlet header has a refrigerant outlet through which the refrigerant flows out from the condensation section; and the supercooling section has a refrigerant inlet into which the refrigerant flows from liquid receiver,   wherein the base member is joined to the header tank in a state in which the refrigerant inflow hole of the base member of the liquid receiver communicates with the refrigerant outlet of the condensation section outlet header and the refrigerant outflow hole communicates with the refrigerant inlet of the supercooling section inlet header.       

     8) A condenser comprising a condensation section; a supercooling section provided below the condensation section; 
     and a liquid receiver which is provided between the condensation section and the supercooling section and which receives gas-liquid-mixed-phase refrigerant from the condensation section and separates the gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant, 
     wherein the condensation section includes a condensation section outlet header whose longitudinal direction coincides with a vertical direction, and a heat exchange path formed by a plurality of heat exchange tubes which are disposed in parallel such that their longitudinal direction coincides with a left-right direction and they are spaced from one another in the vertical direction and each of which is connected, at one end in the longitudinal direction, to the condensation section outlet header; the supercooling section includes a supercooling section inlet header disposed on the lower side and adjacent to the condensation section outlet header, and a heat exchange path formed by a plurality of heat exchange tubes which are disposed in parallel such that their longitudinal direction coincides with the left-right direction and they are spaced from one another in the vertical direction and each of which is connected, at one end in the longitudinal direction, to the supercooling section inlet header; and the liquid receiver is composed of the liquid receiver described in par. 6), 
     wherein the condensation section outlet header and the supercooling section inlet header are provided in a single header tank; the condensation section outlet header has a refrigerant outlet through which the refrigerant flows out from the condensation section; and the supercooling section has a refrigerant inlet into which the refrigerant flows from liquid receiver, 
     wherein the close contact surface of one fixing lug of the base member of the liquid receiver is brought into close contact with an outer surface of the header tank such that the refrigerant inflow hole communicates with the refrigerant outlet of the condensation section outlet header, the close contact surface of the other fixing lug is brought into close contact with the outer surface of the header tank such that the refrigerant outflow hole communicates with the refrigerant inlet of the supercooling section inlet header, and in this state, the two fixing lugs are joined to the header tank through use of a brazing material; and the spacer portion of the cylindrical body of the tank member of the liquid receiver is brought into close contact with the outer surface of the header tank and is brazed to the header tank through use of a brazing material. 
     In the liquid receiver of any one of pars. 1) to 6), a female screw is provided in a region of the inner circumferential surface of the base member, the region being located between the first end and the second end of the base member; and a refrigerant inflow hole and a refrigerant outflow hole are formed in a portion of the base member, which portion is located on the second end side with respect to the female screw, to be separated from each other such that the refrigerant inflow hole is located on the second end side and the refrigerant outflow hole is located on the first end side. Therefore, the distance from the first end of the base member to the end of the refrigerant inflow hole on the side toward the second end of the base member in the liquid receiver can be made relatively short. Accordingly, when a refrigerating cycle including a condenser having this liquid receiver is charged with refrigerant, a portion of the internal space of the liquid receiver, which portion is located on the side toward the first end of the base member with respect to the refrigerant inflow hole, is filled with liquid-phase refrigerant within a relatively short period of time. As a result, in an early stage, the refrigerant charge amount of the refrigerating cycle can reach a proper charge amount at which the degree of supercooling becomes constant. In addition, the internal volume of a portion of the internal space of the liquid receiver, which portion is located on the side toward the second end of the base member with respect to the refrigerant inflow hole, is relatively large. Therefore, the width of a stable range within which the degree of supercooling becomes constant; i.e., the width of the range of the refrigerant charge amount within which the degree of supercooling becomes constant, increases. As a result, supercooling characteristics which are more stable against load fluctuation and leakage of refrigerant are obtained. 
     Also, since the thicknesses of the base member and the tank member can be set to proper thicknesses suitable for their functions, weight reduction and cost reduction become possible. For example, the thickness of the base member can be minimized within a thickness range which allows formation of the female screw, and the thickness of the tank member can be minimized within a thickness range which allows the tank member to have a required strength against pressure. 
     Further, since the refrigerant inflow hole and the refrigerant outflow hole are formed in the base member, positional discrepancy between the two holes can be prevented. In the case of the liquid receiver disclosed in the above-mentioned publication, the refrigerant inflow hole into which refrigerant flows from the condensation section of the condenser is formed in the body portion, and the refrigerant outflow hole from which refrigerant flows to the supercooling section of the condenser is formed in the female screw forming portion. Therefore, when the body portion and the female screw forming portion are combined, positional discrepancy may occur between the two holes. 
     According to the liquid receiver of par. 2), when a refrigerating cycle including a condenser having this liquid receiver is charged with refrigerant, it is possible to effectively shorten the time required for the liquid-phase refrigerant to fill the portion of the internal space of the liquid receiver, which portion is located on the side toward the first end of the base member with respect to the refrigerant inflow hole. In addition, the size and weight of the base member can be reduced. 
     According to the liquid receiver of par. 3), the refrigerant having flowed into the liquid receiver through the refrigerant inflow hole passes through the filter without fail. Therefore, it is possible to reliably prevent the liquid-phase refrigerant flowing from the interior of the liquid receiver into the supercooling section inlet header from containing foreign substances. 
     According to the liquid receiver of par. 4), the base member can be manufactured by cutting a blank formed of, for example, extrudate, into a predetermined length and performing machining or the like for portions to be machined, and the cylindrical body of the tank member can be manufactured by cutting a blank formed of, for example, extrudate, into a predetermined length. Therefore, work for manufacturing these members becomes relatively simple. 
     According to the condenser of par. 7), when a refrigerating cycle including a condenser having this liquid receiver is charged with refrigerant, a portion of the internal space of the liquid receiver, which portion is located on the side toward the first end of the base member with respect to the refrigerant inflow hole, is filled with liquid-phase refrigerant within a relatively short period of time. As a result, in an early stage, the refrigerant charge amount of the refrigerating cycle can reach a proper charge amount at which the degree of supercooling becomes constant. In addition, the internal volume of a portion of the internal space of the liquid receiver, which portion is located on the side toward the second end of the base member with respect to the refrigerant inflow hole, is relatively large. Therefore, the width of a stable range within which the degree of supercooling becomes constant; i.e., the width of the range of the refrigerant charge amount within which the degree of supercooling becomes constant, increases. As a result, supercooling characteristics which are more stable against load fluctuation and leakage of refrigerant are obtained. 
     According to the condenser of par. 8), when the member constituting the header tank of the condenser, the closing member of the tank member of the liquid receiver, and the connection ring are each formed of a brazing sheet having brazing material layers on opposite sides thereof, all the metallic components of the condenser and all the components of the liquid receiver, excluding the plug and the seal members, can be brazed together in a furnace. Therefore, work for manufacturing the condenser becomes simple. In addition, by the actions of the two fixing lugs and the spacer portion, the predetermined postures of the base member and the cylindrical body of the tank member can be maintained during the brazing in the furnace.