Receiver drier

Abstract

 In a receiver drier for a refrigerating system an inserted connector head H having inlet/outlet ports 8, 9 is rigidly coupled to a casing cylinder end of a casing wall of a substantially cylindrical casing 1 by circular inward plastic deformation D of the casing wall.

Description

[0001] The invention relates to a receiver drier for a refrigerating system operating with a liquid and/or gaseous refrigerant particularly for an automotive air-conditioning system.

[0002] The connector head of a metallic receiver drier casing of DE 36 06 029 is unitarily formed with the casing wall by forging. In an alternative embodiment (Fig. 23) the separately prefabricated metallic connector head inserted into the casing end is fixed in place by welding.

[0003] The separately fabricated connector head of the receiver drier of DE 29 710 638 U is inserted into the open casing end and is fixed in place by a bayonet connection or a threaded connection. The connector head and the casing are made from plastics materials enforced by long glass fibres.

[0004] The connector head of the receiver drier of DE 90 11 384 U is secured in place in the open end of the drier casing by forming the opening edge of the casing into a circumferential groove of the connector head. The casing is made from fibre reinforced plastics materials.

[0005] In the recent past in most cases the connector head is secured in the open end of the casing by welding or soldering. The preparation of this connection is cost intensive. A welded connection between the connector head and the casing of a receiver drier needs a relatively big diameter of the casing. There is, however, an increasing demand for slim and small diameter receiver driers, particularly when the receiver drier is to be combined with a condenser usually having a shallow condenser casing.

[0006] It is a task of the invention to provide a receiver drier of the kind disclosed and which can be fabricated with low costs and with small diameter dimensions. Furthermore, the receiver drier concept should allow to provide a simple and tight connection of the receiver drier with the mounting structure to which the receiver drier is to be mounted, even in case of CO₂ refrigerant in the system. Of particular interest is to achieve a small diameter receiver drier apt to be combined with a condenser casing in a space saving manner.

[0007] Said task is achieved by the features of claim 1

[0008] A rigid coupling between the casing and the connector head defined by circular inward plastic deformation of the casing wall surprisingly allows to design the receiver drier with very small outer diameter, as it is, e.g., desirable for combining the receiver drier with a condenser. The connection easily can be sealed reliably and is easy to manufacture. This connection principle is useful for receiver driers installed separately from or at or integrated into a condenser.

[0009] A reliable and secure joint is achieved when one circumferential wall region is crimped inwardly. Of course, there might be provided two or even more adjacent circumferential crimpings to safely fix the connector head in the casing end.

[0010] The casing wall either is crimped in circumferential direction continuously, or in separated crimped wall spots.

[0011] To achieve a reliable fixation of the connector head the circumferential crimping or the crimped wall spots may engage into a circumferential continuous outer groove or in circumferentially distributed depressions of the connector head. This allows to achieve a durable form-fit and a force-fit.

[0012] The casing wall may be deformed inwardly either directly at a casing wall end or in axial distance from the casing wall end.

[0013] The sealing effect between the connector head and the casing wall is not only provided by the inward deformation of the casing wall, but in addition by at least one O-ring or elastomeric sealing ring or a metallic welding ring sealing assembly located adjacently to said inward deformation of the casing wall. In other words, the inward deformation of the casing wall mainly serves to reliably connect the connector head to the casing, while the sealing assembly assures the necessary tightness against the relatively high interior pressures during operation of the receiver drier.

[0014] It is expedient to product the connector head of steel, aluminium or another light metal alloy or plastics material, and to manufacture the casing or casing wall of aluminium or another light metal alloy or even steel. Aluminium or steel provide the necessary rigidity of the inwardly deformed circumferential casing wall region.

[0015] Mounting and/or installation of the receiver drier is facilitated if a hollow connector insert is sealingly and detachably inserted into the inlet/outlet port of the connector head. Instead of the conventional O-ring assembly between the casing wall and the connector head, an elastomeric sealing ring or a metallic welding ring (e.g. made from aluminium) is provided consisting of a tubular sleeve body and at least two axially spaced apart integrated parallel ring structures each of a radial thickness larger than the radial thickness of the sleeve body. The elastomeric sealing ring is easy to manufacture and provides the necessary sealing effect by radial compression in a reliable fashion.
Instead the aluminium welding ring provides the needed tightness after a thermal treatment, e.g. in an oven. The elastomeric sealing ring or the metallic welding ring easily can be placed on the connector insert. The connector insert needs less machining than for several O-rings.

[0016] In the elastomeric sealing ring or in the metallic welding ring, each ring structure should protrude over the sleeve body inner and outer walls substantially symmetrically such that well defined inner and/or outer sealing regions will be achieved.

[0017] It suffices to provide two essentially cylindrical and smooth seat surfaces adjacent to both connector insert ends for placing there a respective elastomeric sealing ring or a metallic welding ring. One of such rings assures the sealing effect in the inlet/outlet port of the connector head, while the other ring provides the necessary sealing effect in the mounting structure to which the receiver drier is to be mounted.

[0018] In an alternative embodiment at least one of the inlet/outlet ports is defined by a unitarily integrated tubular projection of the connector head. The tubular projection has an exterior, substantially cylindrical smooth seat surface for an elastomeric sealing ring or a metallic welding ring consisting of a tubular body with unitarily integrated and parallel ring structures.

[0019] Embodiments of the invention will be explained with the help of the drawing. In the drawing is:

Fig. 1 a schematic side view of a drier receiver,

Fig. 2 an axial section (exploded view) of a part of the receiver drier,

Fig. 3 an axial section of an alternative embodiment of a connector head rigidly coupled to the casing of the receiver drier, and

Fig. 4 an axial section (exploded view) of another embodiment of a connector head, as well as a mounting structure to which the receiver drier is to be mounted.

[0020] A receiver drier R for a refrigerating system operating with a liquid and/or gaseous refrigerant, particularly for an automotive air-conditioning system operating with a standard refrigerant or even with CO₂ (Fig. 1) is intended to be mounted in the refrigerating system in a stand-alone position or in combination or integrated with a not shown condenser. The task of the receiver drier is to store a predetermined amount of refrigerant and to extract water which may be contained in the refrigerant.

[0021] For the extraction of water the receiver drier R contains at least one charge of a desiccant material and filter means (not shown) for holding back impurities.

[0022] The receiver drier R has a substantially cylindrical casing 1 which is closed at a first end 2 by a dome (or a cap) and by an inserted connected head H at the other end 3. The connector head H is formed or equipped with connector inserts C serving to establish a sealed flow connection with a not shown connecting structure to which the receiver drier R is to be mounted. The connector head H is inserted into the casing 1 and is rigidly coupled to the casing 1 by radial inward deformation D in a circumferential wall region A, preferably by crimping.

[0023] The casing 1 can be manufactured from steel or aluminium or another light metal alloy, e.g. by extrusion. The connector head H can be fabricated from aluminium or another light metal alloy or from plastics material.

[0024] Fig. 2 shows that casing 1 has an essentially cylindrical wall 4 terminating at a free end 7. Connector head H has a shoulder 6 limiting the penetration depth of connector head H into casing 1. Connector head H has an exterior, circumferential continuous, outwardly opening groove 5, into which circumferential wall region A is deformed radially, e.g. by crimping or the like. The deformation D is a permanent plastic deformation and provides a form-fit and a force-fit fixing connector head H in place.

[0025] In an alternative embodiment (not shown) the inward deformation D can consist of a series of circumferentially separated indents or depressions of the casing wall 4 engaging either into groove 5 or into a series of respectively designed exterior recess of the connector head H.

[0026] Shoulder 6 and casing end 7, preferably, abut each other. In order to assure sufficient tightness of the joint at least one O-ring 10 is located in connector head H in radial contact with the inner side of casing 4. In the case shown two axially distant O-rings are provided at the side of the circumferential deformation D remote from the free end 7.

[0027] In a not shown embodiment instead of two O-rings a special elastomeric sealing ring or a metallic welding ring (of aluminium) may be inserted similar to the ring 13 shown on the upper connector insert C in Fig. 2. Connector head H contains an inlet port 8 and an outlet port 9.

[0028] Connector inserts C are provided for insertion into the respective ports 8, 9. Each connector insert C is a separately fabricated part made from aluminium or plastics material. Each connector insert C is of tubular shape and has two essentially cylindrical and smooth seat surfaces 11, 12 separated by an intermediate land 17 and shoulders 16.

[0029] The upper connector insert C of Fig. 2 is equipped with two rings 13 either of elastomeric material or of aluminium, each consisting of a tubular sleeve body 14 with in this case two unitarily integrated and parallel ring structures 15. Each ring structure 15 protrudes beyond the inner and outer surfaces of the sleeve body 14. Each ring structure 15 is provided at a short distance from the adjacent sleeve body end. The axial distance between the ring structures 15 is larger than their respective distance from the adjacent sleeve body end. In case of an elastomeric ring 13 the dimension of ring 13 is selected such that at least the ring structures 15 are compressed radially as soon as the connector insert C is inserted into port 8 or 9, respectively. The other end of the connector insert C then is inserted in a respective port of a connecting structure, like into the connecting structure 19 of Fig. 4. In case of an aluminium welding ring 13 the sealing effect is provided after a thermal treatment (welding), e.g. in an oven.

[0030] In the lower connector insert C in Fig. 2 is equipped with two pairs of O-rings 13' instead of rings 13. The O-rings 13' are located in distinct outer grooves of the connector insert C.

[0031] In the alternative embodiment of Fig. 3 connector head H is rigidly coupled to the casing 1 by inward deformation D of casing wall 4 and only has inlet port 8 with an inner wall 18 intended for co-action with either a ring 13 of the upper connector insert C of Fig. 2, or the O-rings 13' of the lower connector insert C in Fig. 2. The other connector C of outlet port 9 is constituted by a unitarily tubular projection of connector head H. The projection is machined with a substantially cylindrical and smooth seat surface 11 intended to receive a ring 13 as in Fig. 2.

[0032] Fig. 4 shows an embodiment of a connector head H being manufactured with integrated connectors C each formed by a tubular projection around the prolongation of inlet/outlet ports 8, 9. The connector head H is rigidly coupled to the casing 1 by inward plastic deformation D of casing wall 4 and is sealed by O-rings 10 (or one ring 13). Each tubular projection carries a ring 13, as described in connection with the upper connector insert C in Fig. 2. The connectors C are intended to be inserted into respective ports 20, 21 of a mounting structure 19 to which the receiver drier R is to be mounted. In case of aluminium welding rings 13 they might provide the sealing effect after welding the condenser casing and the casing at the same time in an oven.

[0033] In all embodiments shown, connector head H may contain at least one threaded hole serving to fix connector head H at mounting structure 9. Each of the rings 13 may comprise more than two ring structures 15 in its sleeve body 14. The casing 1 may be extruded from aluminium, e.g. with an integrated ear constituting a fixture for or constituting a mounting bracket itself. The casing and/or the connector head H may be equipped with a socket for a pressure sensor or another type of a sensor

[0034] The receiver drier R as well is useful generally for any type of refrigerating systems, air-conditioning systems or refrigerators. The deformation joint principle is particularly expedient for systems operating with CO₂ as the high pressure refrigerant (about 120 bar instead of about 30 bar of the standard refrigerant).

Claims

1. Receiver drier (R) for a refrigerating system operating with a liquid and/or gaseous refrigerant, comprising a casing (1) having a substantially cylindrical casing wall (4), the casing being closed at one cylinder end (7) by a sealingly inserted connector head (H) containing at least a refrigerant inlet/outlet port, characterised in that the connector head (H) is rigidly coupled to the casing cylinder end by circular inward plastic deformation (D) of the casing wall (4).

2. Receiver drier as in claim 1, characterised in that the casing wall (4) is crimped inwardly in at least one circumferential wall region (A).

3. Receiver drier as in claim 1, characterised in that the casing wall (4) is crimped inwardly in a circumferential series of separated crimped wall spots.

4. Receiver drier as in claim 1, characterised in that the connector head (H) has a circumferential exterior groove (5) or a circumferential series of exterior recess, respectively, and that the crimped circumferential wall region (A) or the crimped wall spots engage into the groove (5) or into the recesses by a permanent form-fit and force-fit.

5. Receiver drier as in claim 2, characterised in that casing wall (4) is crimped at or axially distant from the wall cylinder end (7).

6. Receiver drier as in claim 1, characterised in that at least one O-ring or welding ring assembly (10) is provided axially adjacent to said deformation (D) before the casing wall (4) and the connector head (H).

7. Receiver drier as in at least one of the preceding claims, characterised in that the connector head (H) is made of steel, aluminium or plastics material, and that the casing wall (4) consists of aluminium or steel.

8. Receiver drier as in at least one the preceding claims, characterised in that a hollow connector insert (C) is inserted sealingly and detachably into the inlet/outlet port (8, 9) of the connector head (H) and that an elastomeric sealing ring or a metallic welding ring (13) is provided between the inner port wall (18) and the connector insert (C), the elastomeric sealing ring or metallic welding ring (13) consisting of a tubular sleeve body (14) and of at least two axially spaced apart integrated parallel ring structures (15) each of radial thickness larger than the radial thickness of said sleeve body (14).

9. Receiver drier as in claim 8, characterised in that each ring structure (15) is located at a first distance from the adjacent sleeve body end, and that the axial distance between two adjacent ring structures (15) is larger than said first distance.

10. Receiver drier as in claim 8, characterised in that each ring structure (15) protrudes substantially symmetrically beyond the inner and outer walls of the sleeve body (14).

11. Receiver drier as in at least of one of claims 8 to 10, characterised in that the connector insert (C) has two essentially cylindrical outer seat surfaces (11, 12) adjacent to both connector insert ends, each seat surface carrying one elastomeric sealing ring or metallic welding ring (13), both seat surfaces being separated by a substantially central circumferential land (17) for directly or indirectly limiting the penetration depth of the connector insert (C) in the inlet/outlet port (8, 9).

12. Receiver drier as in at least one of claims 1 to 7, characterised in that at least one of the inlet/outlet ports (8, 9) is defined by a unitarily integrated tubular projection of the connector head (H), and that the tubular projection has an exterior, substantially smooth cylindrical seat surface (11) for an elastomeric sealing ring or a metallic welding ring (13) of tubular shape having at least two unitarily integrated ring structures (15).

Drawing