Abstract:
A reservoir is screwed axially into a base, itself brazed to a collecting compartment of the condenser. It is linked to the former by means of channels recessed into the base. The threads securing the reservoir are protected from any contact with the refrigerating fluid by sealing rings and from external attack by a sleeve covering the outside of the junction area between the reservoir and the base. 
     Applied to air-conditioning application for automobile passenger compartments.

Description:
FIELD OF THE INVENTION 
     The invention concerns a condenser, in particular for a refrigerating fluid in an air conditioning device for the passenger compartment of an automobile, comprising a collection compartment and an intermediate reservoir, for the treatment and/or accumulation of a fluid, with channels linking it to the collection compartment. 
     BACKGROUND OF THE INVENTION 
     As is well known, the intermediate reservoir in such a condenser can perform some or all of the following functions: filtration and/or dehydration of the refrigerating fluid, compensation for variations in its volume, and separation of the gaseous and liquid phases. Interposing it between upstream and downstream sections of the condenser ensures the fluid in the latter circulates only in the liquid state, which is thus supercooled to a point below the temperature at which the liquid changes to a gas, improving the performance of the condenser and making the former relatively independent of the amount of fluid contained in the circuit. 
     EP-A-0 480 330 describes an intermediate reservoir in a vehicle air conditioning condenser secured, so as to be removable, to a base fixedly attached to the collection compartment and traversed by two connecting channels. This reservoir is fitted at its lower end with a head embodied in its wall, which is secured to the base by means of a screw. The connecting channels extend partly into the base and partly into the reservoir head. 
     This conventional configuration is relatively complex and cumbersome. Furthermore, to replace the reservoir, it is necessary to slacken the fixing screw, which can generate serious difficulties related to accessibility within the vehicle. 
     one aim of the invention is to enable these disadvantages to be at least partly remedied. 
     Embodiments of the invention permit simple, convenient methods of fixing the reservoir to the base, thus ensuring these are protected against interior and exterior forces. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a condenser, in particular for a refrigerating fluid in an air conditioning device for the passenger compartment of an automobile, comprising a collection compartment and intermediate reservoir for the treatment and/or Accumulation of a fluid, secured in such a way that it can be removed to a base which is fixedly attached to the collection compartment and traversed by two connecting channels for transferring fluid between the collection compartment and the reservoir, the reservoir and the base having matching threaded surfaces which are joined together to secure the reservoir to the base, with at least one sealing ring preventing the fluid contained in the reservoir from coming into contact with the said threaded surfaces and an additional stopping element protecting the former from external corrosive agents, wherein the topping element is a sleeve covering tightly two surface portions turned radially outwards, belonging to the reservoir and the base respectively and located next to each other in the axial direction. 
     The invention basically comprises a condenser with a collection compartment and an intermediate reservoir for the treatment and/or accumulation of a fluid, which is fixed to the base incorporated in the collection compartment so as to be removable, traversed by two connecting channels for transferring fluid between the collection compartment and the reservoir. 
     In accordance with the present invention, the reservoir and the base have matching threaded surfaces which interconnect to secure the reservoir on the base, at least one sealing ring preventing the fluid contained in the reservoir from coming into contact with the said threaded surfaces, and an inset stopping element protecting the former from external corrosive agents. 
     Some optional features of the invention, additional or alternative, are set out below: 
     The sealing ring is coaxial with the said threaded surfaces. 
     The said stopping element is coaxial with the said threaded surfaces. 
     The said stopping element is an elastic ring fitted axially between the surfaces of the reservoir and the base. 
     The stopping element is a sleeve which just covers two portions of the surface, turned radially outwards, belonging to the reservoir and the base respectively, meeting in the axial direction, the said portions of the surface being joined to the said threaded surfaces by quick-release fittings. 
     The sleeve is fitted tightly to the said portion of the reservoir surface and covers the said portion of the surface of the base loosely. 
     The threaded reservoir surface is an external surface joined to the said portion of the reservoir surface by a shoulder, the threaded surface and the said surface portion of the base being provided on the internal and external faces of an annular wall, adjacent to a free axial end of the former. 
     On its inner face, the sleeve has an annular rib fitting between the said collar and the said free end. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Features and advantages of the invention will be described in greater detail in the following paragraphs, with reference to the accompanying drawings, in which: 
     FIG. 1 is a front elevation of a condenser in accordance with the invention. 
     FIGS. 2 and 3 are sectional views along the base and the lower part of the reservoir, each associated with a different method of manufacturing the condenser. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the various figures, like reference numerals refer to like parts. 
     Condenser  1 , represented in its entirety in FIG. 1, comprises two collection compartments  3 ,  4  aligned vertically and separated horizontally from each other, linked by numerous horizontal fluid circulation tubes  5 . Each collection compartment is divided into various chambers by means of horizontal partitions  6  such that the fluid circulates, in the tubes  5 , alternately from a chamber in compartment  3  to a chamber in compartment  4  and, conversely, from the upper chamber in compartment  4 , which is linked to an entry manifold  7 , to the lower chamber in compartment  3 . 
     One of the intermediate partitions in collection compartment  3 , designated by reference  6 - 1 , divides chamber  9 - 1  and chamber  9 - 2 , situated above and below partition  6 - 1  respectively, from each other, and these are interconnected exclusively by means of a reservoir  2 , which is aligned vertically and extends along the full length of compartment  3 . Chamber  9 - 2  is in turn divided from the lower chamber of the compartment, designated by reference  9 - 3 , by a partition  6 - 2 . 
     Reservoir  2 , which exhibits approximately a circular symmetry about a vertical axis A, comprises a housing made up of a cylindrical body  10 , which forms the major part of its height, and a narrow collar  11  located on its lower part. In its turn, the collar  11  is subdivided from top to bottom into three parts  12 ,  13  and  14  decreasing in diameter, interconnected by means of radial shoulders, the intermediate region  13  being fitted with a male thread and the lower region  14  having two circumferential grooves formed in it in which are seated two sealing rings  15 . The collar is traversed by an axial manifold  17  which projects upwards inside the reservoir and downwards externally. The annular volume  18  contained between the lateral wall of body  10  and the tubing  17  holds cleaning agents for filtering and/or dehydrating the fluid circulating in the condenser. 
     For the purpose of fluid transmission, reservoir  2  is linked mechanically with collection compartment  3  via a base  20 . This base is for choice a moulded aluminium alloy component, defining a wall  21  approximately centred around an axis A, which delimits a housing  23  open at its top end for the purpose of receiving the collar of reservoir  2 . The lateral surface of housing  23  has in its upper area  24  a female thread matching the thread in area  13  of the reservoir to provide coaxial fixing of the latter on the base. A cylindrical median region  25  of the wall  21  fits into the sealing rings  15 , and a lower cylindrical region  26 , extending below the free end of collar  11 , surrounds the manifold  17  and delimits an annular space with the latter, the free end of which rests on a seating  27  provided at the base of housing  23 , by means of a sealing lip  28 . A supporting tie  33  links the upper end of reservoir  2  mechanically to that of collection compartment  3  to provide a more stable fixing for the reservoir. 
     A fin  29  is attached to the outer surface of wall  21 , in a plane extending approximately through the axis A. This fin has bulges  30  on both sides which accommodate two channels  31 ,  32  aligned parallel to this plane. In an intermediate stage during manufacture of the base, the ends of channel  31  open in housing  23  at the level of the aforementioned annular space, and on the free side of fin  29 , respectively, and channel  31  is inclined upwards from the former end to the latter one. Channel  32  extends horizontally from the free side of the fin to below the housing  23 , where it bends upwards to emerge at the bottom thereof, inside the annular seating  27 . In the finished base, brazed plugs  35 ,  36  provide sealing for the free ends of channels  31 ,  32  and these emerge on the outside solely via passages recessed into lateral bosses formed on the bulges  30 . 
     The base  20  is secured to the collection compartment  3  by brazing the aforementioned lateral bosses to the outer surface of the tubular wall made of sheet aluminium forming the compartment, during the assembly of the condenser by brazing. The recessed passages in the lateral bosses are linked to chambers  9 - 1  and  9 - 2  of the compartment respectively by holes provided in the tubular wall, in which nozzles provided for this purpose engage. The fluid entering the upper chamber of collection compartment  4  via the manifold  7  passes through a first group of tubes as shown by the arrow F 1  to reach the upper chamber of compartment  3 , then through two other groups of tubes as shown by arrows F 2  and F 3 , in order to enter the intermediate chamber of compartment  4  and chamber  9 - 1  of compartment  3 . The condensed fluid thus reaching chamber  9 - 1  passes from the former into the annular space  23  in the base via a lateral passage and via the sloping channel  31 , then enters reservoir  2 , which is screwed into the base, passing outside the manifold  17 . It then traverses the annular volume  18  where it is dehydrated and filtered. The fluid leaves volume  18  via the manifold  17 , reaching the chamber  9 - 2  of collection compartment  3  via horizontal channel  32  and the matching lateral passage in the base. In this way, the tubes  5  and the chambers of compartments  3  and  4  situated above partition  6 - 1 , including chamber  91 , form a section of the condenser through which the fluid upstream of the reservoir passes, whereas the tubes and chambers situated below this partition, including chamber  9 - 2 , form a downstream section. Fluid passes from chamber  9 - 2  to the lower chamber of collection compartment  4  as shown by the arrow F 4  and is then routed to chamber  9 - 3  as shown by the arrow F 5 . Fluid leaves this last chamber and the condenser via manifold  37 . 
     The sealing rings  15  guarantee fluid-fast separation between the interior and exterior of the refrigerating fluid circuit at the junction of reservoir  2  and base  20 . They thus protect the threaded surfaces  13 ,  24  against any contact with the fluid. Moreover, to protect these same threaded surfaces against external corrosive agents, a sleeve  40 , in the embodiment shown in FIG. 2, is provided, formed for example from a piece of moulded plastic, secured to the reservoir by fitting in the area  12  of the collar. Sleeve  40  projects downwards beyond area  12  to cover tightly the outer surface  19  of the annular wall  21  in the base, next to its free end  41 . It has a rib  42  projecting radially towards the inside, between the edge  41  and the shoulder  43  which links areas  12  and  13  of the reservoir collar. The sleeve thus forms a baffle between the outside and the threaded surfaces  13 ,  24  protecting the former against projections. 
     In the variant shown in FIG. 3, the reservoir and the base are identical to those in FIG. 2, the reference signs relating to their various elements not being repeated. Sleeve  40  is replaced by an elastomer ring  50  surrounding the area  13  of the collar, above the threading thereof, which can be clamped axially, when the reservoir is screwed, between the edge  41  and the collar  43 .