Filter desiccant unit for a condenser with a receiver canister

Abstract

 The present invention relates to a filter desiccant unit for a condenser with a receiver canister (5) for automotive air conditioning systems comprising: a filter element (12, 12'); a desiccant container (24); and a post (30; 30', 30", 30''') supporting both the filter element. (12; 12') and the desiccant container (24).

Description

Introduction

[0001] The present invention relates generally to a filter desiccant unit for a condenser with a receiver canister for automotive air conditioning systems and in particular to a filler desiccant unit for a condenser with an integral receiver canister for automotive air conditioning systems.

[0002] Automotive air conditioning systems typically include a receiver canister that serves as a refrigerant reservoir, the receiver-canister being attached to or integral with a condenser of the automotive air conditioning system.

[0003] A conventional automotive air conditioning system including an integral receiver canister is known from EP-A-1 079 186. As shown in Fig. 1 the conventional automotive air conditioning system is comprised of a condenser C of the crossflow type having an inlet/outlet header tank 1 on one side thereof and a return tank header 2 on the other side thereof. Each tank header is divided into an upper section U and a lower section L by means of respective separators 3 and 4.

[0004] A receiver canister 5 is integrally attached to the return tank header 2 in the manner shown in Fig. 1. An inlet opening 6 connects the upper section U of the return tank header 2 to the receiver canister 5 while an outlet opening 7 connects the lower section L of the return tank header 2 to the receiver canister 5. The condenser C is divided into an upper condensing section 8 and a lower sub-cooling section 9.

[0005] The operation of the condenser with receiver canister of EP-A-1 079 186 is as follows. Compressed refrigerant vapour enters the upper condensing section 8 through the upper section U of the inlet/outlet header tank 1. The vapour is condensed in the upper condensing section 8 and enters the upper section U of the return tank header 2 as saturated liquid. From there it flows through the inlet opening 6 into the receiver canister 5 where it backs up to a liquid level of varying height. From the receiver canister 5 liquid refrigerant flows through the outlet opening 7 into the sub-cooling section 9 of the condenser C where it is further cooled down below the saturation temperature. From the sub-cooling section 9 the refrigerant exits the condenser C through the lower section L of the inlet/outlet header 2.

[0006] In Fig. 1 the receiver canister 5 is represented as an empty container having for instance a substantially cylindrical form with no particular internal structure. Nevertheless, as known from EP-A-1 079 186 and shown in present Fig. 2, the receiver-canister 5 includes a desiccant unit 10 with a desiccant container 24 preferably in form of a tube of mesh material which is slidable within the receiver canister 5 and which is filled with a conventional granular desiccant material.

[0007] The tube is sealed at one end thereof and is fixed at the opposite end thereof to a lobed base 28, which is provided with a post 30 and a standoff 26 at its opposite end. The lobed base 28 makes an interference fit with the inside of the receiver canister 5 and allows at the same time refrigerant flow towards a top end cap 36 of the receiver canister 5. In use the standoff 26 rests on a bottom end cap 34 of the receiver canister 5, the post 30 having a length such as to leave the inlet and outlet openings 5 and 6 unblocked, as apparent from Fig. 2.

[0008] A further general requirement for automotive air conditioning systems is the presence of a filter element capable of retaining a broad spectrum of soluble contaminants, as known from EP-A-1 132 695.

[0009] The filter element of the integral receiver canister according to EP-A-1 132 695 is part of a desiccant containment of the desiccant unit, which makes it impossible to position the filter element independently from the desiccant element within the assembly. In addition the filter element of EP-A-1 132 695 which is provided at the outlet zone of the integral receiver canister is more difficult to clean and/or remove. Furthermore the desiccant containment of EP-A-1 132 695 can not be readily adapted to various receiver canister sizes.

Object of the invention

[0010] In view of the above it is an object of the present invention to provide for an improved filter desiccant unit for a condenser with a receiver canister for automotive air conditioning systems. This object is achieved by a filter desiccant unit for a condenser with a receiver canister for automotive air conditioning systems according to claim 1.

General description of the invention

[0011] The filter desiccant unit for a condenser with a receiver canister for automotive air conditioning systems of the present invention comp rises a filter element, a desiccant container and a structure, such as a post, supporting both the filter element and the desiccant container. The filter element preferably extends in a substantially perpendicular manner to the post.

[0012] In a preferred embodiment, the filter element is substantially disk shaped, the filter element being provided with a filtering mesh, which is an integral part of a disc formed or fixed onto the post. The filtering mesh may be attached to the disc in a bag type manner in order to increase the free filter surface available to refrigerant passing therethrough. In another embodiment, the filter element may be a truncated cone shaped filter-element extending symmetrically around at least a section of the post.

[0013] The length of the post is preferably substantially equal to the length of the longitudinal axis of the receiver canister such that, in the assembled state of the filter desiccant unit with the receiver canister, the post is clamped between a top end cap and a bottom end cap of the receiver canister. The diameter of the post may be substantially smaller than the diameter the receiver-canister.

[0014] In a first embodiment, the post is substantially straight and extends substantially centrally of the receiver canister. With this embodiment, the desiccant container may be provided in form of a bag that is suspended from the post, the post being provided with a suspension device at its top. Alternatively the desiccant container is provided in form of a bag that is maintained by a base formed onto the post.

[0015] In another embodiment, the post has a bent configuration including a lower section for holding the filter element and extending substantially centrally of the receiver canister, an offset section extending near an inner wall of the receiver canister and a pin extending from the offset section towards the center of the receiver canister.

[0016] The present invention accordingly provides for a filter desiccant unit including a filter element, which avoids the drawbacks of the prior art and provides for a filter desiccant unit, which can be easily used with a plurality of differently sized receiver canisters. Furthermore the present invention provides for a filter desiccant unit, wherein the desiccant container can be readily removed along with the filter element from the receiver canister and wherein the desiccant container and the filter element can be accurately positioned within the receiver canister.

[0017] An additional advantage of the present invention is achieved in the provision of a filter desiccant unit having an integral architecture making it a compact assembly as well as easy to manufacture and handle. This filter desiccant unit is easily adaptable to different integral receiver canister dimensions and configurations.

[0018] Moreover, the present invention also provides the advantage of a filter desiccant unit for automotive air-conditioning systems including a filter element with improved filtering performance due preferably to an increased filter surface.

[0019] The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

Fig. 1.

shows an automotive air conditioning system according to the prior art including an integral receiver canister;

Fig. 2.

shows a receiver canister according to the prior art with a desiccant unit assembled within the receiver canister;

Fig. 3.

shows a filter desiccant unit with a filter element according to an embodiment of the present invention, wherein the filter desiccant unit; is mounted within a receiver canister;

Fig. 4.

shows a filter desiccant unit with a filter element according to another embodiment of the present invention; and

Fig. 5.

shows a filter desiccant unit with a filter element, according to yet another embodiment of the present invention

Fig. 6.

shows a filter desiccant unit with a filter element, according to yet another embodiment of the present invention.

[0020] With reference to the non-limitative example of Fig. 3 the filter desiccant unit according to the present invention, which is generally indicated at reference numeral 10, is shown inserted into the receiver canister 5. The desiccant unit 10 includes a post 30 integrating according to the present invention a filter element 12 and the desiccant container 24 containing granular desiccant material.

[0021] Since the receiver canister 5 is an integral part of the condenser C the general requirement is that the desiccant unit 10 including the desiccant container 24 and the filter element 12 can be removed and replaced as an individual component or subassembly independently of the receiver canister 5 during the lifetime of the condenser C. For this reason either the top end cap 36 or the bottom end cap 34 of the receiver canister 5 or both can be removable according to the present invention.

[0022] The post 30 is preferably located centrally within the substantially cylindrical receiver canister 5. The diameter of the post 30 is substantially smaller than that of the receiver-canister 5. According to one aspect of the present invention the length of the post 30 is chosen so that it makes an interference fit, with the bottom and top end caps 34, 36 of the receiver canister 5, thus fixing the position of the post 30 within the receiver canister 5.

[0023] By virtue of the above described arrangement the filter desiccant unit according to the present invention can be used with variously sized receiver canisters 5 by merely cutting the post 30 to an appropriate length.

[0024] Furthermore, advantageously, means that are well known to the person skilled in the art, can be provided for adjusting the position of the filter element 12 on the post 30 in order to accommodate varying spacings between and positions of the openings 6 and 7. At any rate, due to its mounting to the post 30 as shown in Fig. 3, even a fixed filter element 12 may accommodate to a certain extent for a variance of spacing between and positions of the openings 6 and 7.

[0025] In order to make sure that the filter element 12 fulfils its function all of the refrigerant has to flow through the filter element 12. To this end the present filter element 12 is provided with a filtering mesh 13 which is an integral part of a disc 14 formed or fixed onto the post 30. As shown in Fig. 3 the disk 14 is provided with openings that are covered with the filtering mesh 13, such that fluid passage may occur. The disk 14 has an outside diameter that makes a tight interference fit with the inner wall of the receiver canister 5 thus avoiding that any refrigerant bypasses the filter element 12.

[0026] The position of the disc 14 on the post 30 is chosen such as to locate the filter element 12 between the inlet opening 6 and the outlet opening 7 of the receiver canister 5. Its position may be varied, as explained hereinabove.

[0027] According to one advantageous aspect of the invention the filtering mesh 13 can also be attached to the disc 14 in a bag type manner in order to increase the free filter surface available to refrigerant passing therethrough. Such an embodiment of the invention is represented in Fig. 6.

[0028] The desiccant container 24 may be provided in form of a bag that is suspended from the post 30 which is provided with a suspension device at its top. The desiccant bag maintains a generally cylindrical shape dimensioned as to keep a small radial clearance to the inner wall of the receiver canister 5. The height of the desiccant bag and the suspension point thereof are chosen as to maintain the lower end of the desiccant bag above the inlet opening 6, thus ensuring free flow of the refrigerant into the receiver canister 5. According to one aspect of the invention the desiccant bag is fixed to the post 30 due to its envelope type configuration and to the suspension device on the top of the post 30.

[0029] The position of the desiccant bag could also be maintained by a base 28' formed onto the post 30 just above the inlet opening 6 of the receiver canister 5 instead of the suspension device. In the latter variation of the invention the base 28' may be shaped in a similar manner to that shown in Fig. 2 at reference numeral 28.

[0030] In the variation shown in Fig. 4, wherein same numerals as in Fig. 3 are used to designate same features, the post is de-centered and includes a lower substantially central section 30', an offset section 30" extending near the inner wall of the receiver canister 5 and a pin or a stud 30''' extending from the offset section 30" towards the center receiver canister 5. The pin or the stud 30''' provide for the suspension device in a similar manner to the embodiment of Fig. 3.

[0031] Also in the embodiment of Fig. 4 the position of the desiccant bag can also be maintained by a base 28' formed onto the lower section 30' of the post 30 just above the inlet opening 6 of the receiver canister 5 instead of the suspension device. Also in the latter variation of the invention the base 28' may be shaped in a similar manner to that shown in Fig. 2 at reference numeral 28.

[0032] According to a further aspect of the present invention, which is shown in Fig. 5, the filter element 12' is in the shape of a truncated cone or a bucket. The filter element shown in Fig. 5 provides for particular advantages in that it has an increased filter surface and the particles of refrigerant will remain inside the filter element 12' during service. The filter element 12' is provided preferably with a filtering mesh similar to that of the embodiments described in respect to figures 3 and 4.

[0033] Although Fig. 5 shows the filter desiccant unit provided with a lobed base 28" for maintaining the position of the desiccant bag the person skilled in the art will appreciate that the truncated cone shaped filter element 12' can be advantageously used in conjunction with the filter desiccant unit embodiments shown in figures 2 and 3 hereinbefore.

[0034] From the foregoing, it will be observed that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present invention. The present disclosure is to be understood broadly and no limitation with respect to the specific embodiments herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as falls within the scope of the claims.

[0035] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

1. A filter desiccant unit for a condenser with a receiver canister (5) for automotive air conditioning systems comprising:

a filter element (12, 12');

a desiccant container (24); and

a post (30; 30', 30", 30''') supporting both the filter element (12; 12') and the desiccant container (24).

2. The filter desiccant unit according to claim 1, wherein the filter element (12) extends in a substantially perpendicular manner to the post (30; 30', 30", 30''').

3. The filter desiccant unit according to claims 1 or 2, wherein the filter element (12) is substantially disk shaped, the filter element (12) being provided with a filtering mesh (13) which is an integral part of a disc (14) formed or fixed onto the post (30; 30', 30", 30''').

4. The filter desiccant unit according to claim 3, wherein the filtering mesh (13) is attached to the disc (14) in a bag type manner in order to increase the free filter surface available to refrigerant passing therethrough.

5. The filter desiccant unit, according to claim 1, wherein the filter element (12') is a truncated cone shaped filter-clement extending symmetrically around at least a section of the post (30, 30', 30", 30"').

6. The filter desiccant unit according to one or more of the claims 1 to 5, wherein the post (30) is substantially straight and extends substantially centrally of the receiver canister (5), and wherein said desiccant container (24) is provided in form of a bag that is suspended from the post (30), the post (30) being provided with a suspension device at its top.

7. The filter desiccant unit according to one or more of the claims 1 to 5, wherein the post (30) is substantially straight and extends substantially centrally of the receiver canister (5), and wherein desiccant container (24) is provided in form of a bag that is maintained by a base (28') formed onto the post (30).

8. The filter desiccant unit according to one or more of the claims 1 to 5, wherein the post (30', 30", 30''') has a bent configuration including a lower section (30') for holding the filter element: (12, 12') and extending substantially centrally of the receiver canister (5), an offset section (30") extending near an inner wall of the receiver canister (5) and a pin (30''') extending from the offset section (30") towards the center of the receiver canister (5), and wherein said desiccant container (24) is provided in form of a bag that is suspended from the pin (30'''), the pin (30''') being provided with a suspension device.

9. The filter desiccant unit according to one or more of the claims 1 to 5, wherein the post (30', 30", 30"") has a bent configuration including a lower section (30') for holding the filter element. (12; 12') and extending substantially centrally of the receiver canister (5), an offset section (30") extending near an inner wall of the receiver canister (5) and a pin (30''') extending from the offset section (30") towards the center of said receiver canister (5), and wherein desiccant container (24) is provided in form of a bag that is maintained by a base (28') formed onto the lower section (30') of the post (30', 30", 30''').

10. The filter desiccant unit according to one or more of the claims 1 to 9, wherein the length of the post (30; 30', 30", 30''') is substantially equal to the length of the longitudinal axis of the receiver canister (5) such that, in the assembled state of the filter desiccant unit with the receiver canister (5), the post (30; 30', 30", 30''') is clamped between a top end cap (36) and a bottom end cap (34) of the receiver canister (5).

11. The filter desiccant unit according to one or more of the claims 1 to 10, wherein the filter element (12, 12'), in the assembled state of the filter desiccant unit with the receiver canister (5), is arranged on the post (30; 30', 30", 30''') such that it is positioned between the inlet and outlet openings (5, 6) of the receiver canister (5) and to leave them unblocked, and wherein the filter element (12, 12') makes a tight interference fit with the inner wall of the receiver canister (5) thus avoiding that any refrigerant bypasses the filter element (12, 12').

12. The filter desiccant unit according to one or more of the claims 1 to 11, wherein the desiccant container (24) maintains a generally cylindrical shape dimensioned, as to keep a small radial clearance to the inner wall of the receiver canister (5) when the filter desiccant unit is assembled with the receiver canister (5).

13. A filter desiccant unit for a condenser with a receiver canister (5) for automotive air conditioning systems comprising:

a filter element (32') with the shape of a truncated cone;

a desiccant container (24); and

a structure supporting both the filter element (12') and the desiccant container (24).

Drawing