REFRIGERANT EXCHANGE ARRANGEMENT

Abstract

A refrigerant exchange arrangement is claimed with a first oil-trapping chamber (10) and a second oil-trapping chamber (11). A refrigerant exchange arrangement of simple construction is to be realised. For this purpose, the second oil-trapping chamber (11) is disposed within the first oil trapping chamber.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is entitled to the benefit of and incorporates by reference essential subject matter disclosed in International Patent Application No. PCT/DK2007/000318 filed on Jun. 28, 2007 and German Patent Application No. 10 2006 030 698.8 filed Jun. 30, 2006.

TECHNICAL FIELD

The invention concerns a refrigerant exchange arrangement with a first oil-trapping chamber and a second oil-trapping chamber.

BACKGROUND OF THE INVENTION

In the following, the invention is described in connection with the exchange of a refrigerant in the air-conditioning system of a vehicle. However, it can also be used in applications, in which similar problems occur.

When servicing the air-conditioning system of a vehicle, it is in many cases necessary to exchange the refrigerant. The term “exchange” does not necessarily mean that the refrigerant contained in the air-conditioning system is completely replaced by a new refrigerant. In many cases, it will be sufficient to dewater the refrigerant and/or to replace the oil contained in the refrigerant by new oil. Further, during such a servicing, it should be tested, if any parts of the air-conditioning system should be replaced and if the air-conditioning system is tight.

When the refrigerant is removed from the air-conditioning system, it is firstly required to remove the oil from the refrigerant. This is the case, irrespective if the refrigerant will subsequently be returned into the air-conditioning system or used in a different way. In order to trap the oil, the refrigerant with the oil is led into the first oil-trapping chamber. Here, the flow of the mixture of refrigerant and oil is slowed down, so that the oil precipitates from the refrigerant. The oil is then at the bottom of the first oil-trapping chamber. If then the first oil-trapping chamber is heated, the refrigerant can be evaporated, because it has a lower boiling point than the oil. The refrigerant gas is then led across a filter drier, which removes water from the refrigerant gas. After that the refrigerant gas is compressed by a compressor. In the compressor the refrigerant gas will again get in touch with oil, which is then removed from the refrigerant gas in the second oil-trapping chamber. This compressor oil is led to the compressor again, and the refrigerant gas from the second oil-trapping chamber is led via a condenser, and in many cases also a further filter drier, to a collector.

The use of two oil-trapping chambers makes the design of such a refrigerant exchange arrangement complicated. As from time to time the refrigerant exchange arrangement must also be serviced, it has to be detachable and a reassembly also has to be possible. For this purpose, various parts have to be connected to each other and sealed in relation to each other.

BRIEF SUMMARY OF THE INVENTION

The invention is based on the task of providing a refrigerant exchange arrangement with a simple design.

With a refrigerant exchange arrangement, this task is solved in that the second oil-trapping chamber is located inside the first oil-trapping chamber.

Thus, it is only necessary to seal the outer, that is, the first oil-trapping chamber in relation to the environment. Accordingly, only one sealing is required, namely towards the outside. A corresponding sealing between the two oil-trapping chambers is not required. If refrigerant or oil should penetrate from one oil-trapping chamber to the other, this is not critical. As a smaller number of parts is required, the manufacturing is more cost-effective. As only one chamber has to be sealed towards the outside, the leakage risk is reduced.

Preferably, a gas path out of the second oil-trapping chamber is limited by a wall of the first oil-trapping chamber. Due to the previously occurring compression, the refrigerant supplied to the second oil-trapping chamber is at a higher temperature. Now, this higher temperature can be used to heat the first oil-trapping chamber. In order to realise the most direct possible heat transition from the second oil-trapping chamber to the first oil-trapping chamber, the gas is guided along the wall of the first oil-trapping chamber. This has two advantages. Firstly, the heated refrigerant gas is cooled in the second oil-trapping chamber after the precipitation of the oil. Secondly, the heat is not lost, but can be used to heat the first oil-trapping chamber.

It is preferred that an insert is arranged in the second oil-trapping chamber, which limits the gas path together with the wall of the first oil-trapping chamber. By means of the insert, the path along the wall of the first oil-trapping chamber can be specified relatively exactly. An insert is easy to make and to insert into the second oil-trapping chamber. This keeps the manufacturing costs low. In connection with servicing, the insert can be removed from the second oil-trapping chamber and cleaned. This reduces the risk of the gas path eventually blinding. When the insert has been removed from the second oil-trapping chamber, the gas path is accessible from the outside, as the wall of the first oil-trapping chamber is missing as cover.

Preferably, the outside of the insert has at least one spirally shaped groove. Thus, the spirally shaped groove surrounds the insert with a small pitch. This results in a relatively long length of the gas path and thus a sufficient time for the heated refrigerant gas to transfer its heat to the first oil-trapping chamber.

Preferably, the insert is made of a plastic material. A plastic material can easily be shaped to the desired form. Usually it is also easy to clean, so that the servicing is facilitated.

Preferably, at least one outer wall of the first oil-trapping chamber is made in one piece with a bottom plate. The term “bottom plate” does not necessarily mean that the bottom plate is plane. The bottom plate simply forms a limitation of the oil-trapping chamber in addition to the outer wall. If the outer wall is made in one piece with the bottom plate, the result is, in a manner of speaking, a “barrel” that surrounds the first oil-trapping chamber. If the outer wall is made in one piece with the bottom plate, a smaller number of pieces must be handled during dismounting of the refrigerant exchange arrangement, so that the handling as a whole becomes simpler. Also the number of parts to be sealed in relation to each other is smaller.

Preferably, a dividing wall between the first oil-trapping chamber and the second oil-trapping chamber is made in one piece with the bottom plate. In connection with both the outer wall and the dividing wall, the term “in one piece with” means that the walls are fixedly connected to the bottom plate, that is, they cannot be detached from the bottom plate with simple means. Such a connection can be made by welding, soldering, gluing or the like. The corresponding parts can also grouted to each other or be permanently connected to each other in other ways without the use of auxiliary joining means. If the dividing wall between the first oil-trapping chamber and the second oil-trapping chamber is made in one piece with the bottom plate, this automatically results in a sealing between the first oil-trapping chamber and the second oil-trapping chamber at least in the area of the bottom plate. Thus, it can be ensured in a simple manner that the oil introduced into the refrigerant in the compressor and the oil contained in the refrigerant in the air-conditioning system are kept separate from one another.

Preferably, a covering plate is arranged on the side of the first oil-trapping chamber, which is opposite to the bottom plate, the dividing wall engaging said covering plate. This means that the covering plate has a groove, into which the dividing wall projects. In a simple manner, this provides a relatively good sealing between the first oil-trapping chamber and the second oil-trapping chamber in the area of the covering plate. This sealing does not have to be completely tight. A large penetration of refrigerant gas or a refrigerant-oil mixture from the first oil-trapping chamber to the second oil-trapping chamber is avoided.

Preferably, the insert engages the covering plate. In this way it can be ensured that the second oil-trapping chamber and the gas path leaving the second oil-trapping chamber are separated from one another, namely by the insert. Also here, a hermetic sealing is not necessarily required, as oil and refrigerant can pass from one oil-trapping chamber to the other.

Preferably, the outer wall has a fixing flange in the area of the covering plate. On the one side, the fixing flange strengthens the outer wall in the area, where a fixing to the covering plate is anticipated. On the other side, the fixing flange can also be used for locating fixing means, such as screws or bolts.

Preferably, the outlet of the second oil-trapping chamber is connected to a refrigerant collector. Expediently, this connection is made via a condenser and a filter drier. With the refrigerant collector, it is possible to realise an intermittent operation, in which the refrigerant is treated by batch. A large refrigerant supply is then available in the refrigerant collector, which can be used again later to fill the air-conditioning system.

Preferably, a main pipe is connected via a first valve arrangement to the first oil-trapping chamber and via a second valve arrangement to the refrigerant collector, the main pipe having at least one outer connection. The outer connection serves the purpose of connecting the air-conditioning system (or another system), whose refrigerant has to be exchanged. The use of a main pipe simplifies the design. Via the individual valve arrangements the part of the refrigerant exchange arrangement, which is required, can always be connected to the corresponding air-conditioning system.

It is preferred that the main pipe is connected to a vacuum pump via a third valve arrangement. The vacuum pump generates a vacuum, with which, for example, the tightness of the air-conditioning system can be tested. If the vacuum remains for a certain period, this is a sign that the air-conditioning system is tight. If the pressure in the main pipe connected to the air-conditioning system increases, this is a sign that somewhere a leakage exists.

It is also advantageous, if the main pipe is connected via a fourth valve arrangement to a marking substance source. If a leakage has occurred, a marking substance can be taken from the marking substance source and mixed with the refrigerant in the main pipe. This mixture is then led through the air-conditioning system. The marking substance can, for example, be a colouring material. If this colouring material penetrates to the outside somewhere, a leakage has been discovered.

It is also advantageous, if the main pipe is connected via a fifth valve arrangement to an oil reservoir. The refrigerant can then be supplied with “fresh” oil, so that after servicing the air-conditioning system is ready for work again.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is described on the basis of a preferred embodiment in connection with the drawing, showing:

FIG. 1 is a schematic view of a refrigerant exchange arrangement,

FIG. 2 is a section through an oil-trapping unit,

FIG. 3 is a section of the view according to FIG. 2 with a non-sectioned insert, and

FIG. 4 is a perspective view of the oil-trapping unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the form of a diagram, FIG. 1 shows a refrigerant exchange arrangement 1, by means of which a refrigerant can be taken from a schematically shown air-conditioning system 2, be purified and returned into the air-conditioning system 2 again.

The refrigerant exchange arrangement has a main pipe 3, which is connected to two or more outer connections 4, 5. Via the outer connections 4, 5 and valves 4a, 5a, which are allocated to these outer connections 4, 5, the connection to the air-conditioning system 2 is realised. Via a first valve arrangement 6, the main pipe 3 is connected to an oil-trapping unit 7. The valve arrangement has an electrically activated valve 8, for example a solenoid valve, and a non-return valve 9 opening in the direction of the oil-trapping unit 7.

The oil-trapping unit 7 has a first oil-trapping chamber 10 and a second oil-trapping chamber 11. The first oil-trapping chamber 10 is connected to the main pipe 3 via the first valve arrangement 6. A pipe 12 branches off from the first oil-trapping chamber 10 and leads via a filter drier 13 to a compressor 14. From the compressor 14 a pipe 15 extends to the inlet of the second oil-trapping chamber 11. A pipe 16 that can be interrupted or released by an electrically activated valve 17, branches off from the first oil-trapping chamber 10. The pipe 16 leads to a waste oil collector 18.

Also from the second oil-trapping chamber 11a pipe 19 branches off, which can be interrupted or released by an electrically activated valve 20. The line 19 leads to the compressor 14, with the purpose of leading oil back to here.

A gas path 21 leads out of the second oil-trapping chamber 11, said gas path 21 extending through a schematically shown heat exchanger 22 and which can be interrupted by a non-return valve 23 opening in the direction out of the second oil-trapping chamber 11. The gas path 21 leads through a condenser 24 and and a filter drier 25 to a refrigerant collector 26. The filter drier 25 can be combined with the filter drier 13 to one component.

Via a second valve arrangement 27, which is formed by an electrically activated valve 28 and a non-return valve 29 opening in the direction of the main pipe 3, the refrigerant collector 26 is connected to the main pipe 3.

Via a third valve arrangement 30, which can in fact be formed by only one electrically activated valve 31, the main pipe 3 is connected to a vacuum pump 32.

Via a fourth valve arrangement 33, which again is formed by an electrically activated valve 34 and a non-return valve 35 opening in the direction of the main pipe, a marking substance source 36 is connected to the main pipe 3.

An oil reservoir 37 is connected to the main pipe 3 via a fifth valve arrangement 38 comprising an electrically activated valve 39 and a non-return valve 40 opening in the direction of the main pipe 3. The oil reservoir 37 contains fresh oil, which can be added to the refrigerant supplied to the air-conditioning system 2.

The oil-trapping unit 7 is shown as a section in FIG. 2.

The first oil-trapping chamber 10 is surrounded by an outer wall 41, which is made in one piece with a bottom plate 42. Also a dividing wall 43 is made in one piece with the bottom plate 42, the dividing wall 43 being located between the first oil-trapping chamber 10 and the second oil-trapping chamber 11. Accordingly, the second oil-trapping chamber 11 is located inside the first oil-trapping chamber 10.

Both oil-trapping chambers 10, 11 are closed by a covering plate 44 on the side opposite the bottom plate 42. As can be seen from FIG. 4, the covering plate 44 is mounted on a fixing flange 45 and connected to the fixing flange 45 by means of screws 46. Only one single sealing 47 is required between the covering plate 44 and the outer wall 41 in the area of the fixing flange 45, in order to seal the first and the second oil-trapping chambers 10, 11 towards the outside. A transition of oil or refrigerant gas from one oil-trapping chamber into the other is not critical. Merely the sealing towards the outside must be ensured.

In the second oil-trapping chamber 11 an insert 48 is arranged, whose circumference bears on the dividing wall 43 from the inside. In its circumference, the insert has a spirally shaped groove 49, which does, together with the dividing wall 43, limit a gas path 50, which leads out of the second oil-trapping chamber 11 and, together with the dividing wall 43, forms the heat exchanger 22 (FIG. 1).

Both the insert 48 and the dividing wall 43 are, as can be seen from FIGS. 2 and 3, inserted in grooves 51, 52, which are formed in the covering plate 44. Inserting the insert 48 and the dividing wall 43 in these grooves 51, 52 does not necessarily provide an absolute tightness between the various chambers, however, the tightness will be perfectly sufficient for the operation of the refrigerant exchange arrangement.

As can be seen from FIG. 4, practically all valve arrangements and valves 4a, 6, 27, 30, 33, 38 are arranged on the covering plate 44, except for the two valves 17, 20 which control the oil outlet from the oil-trapping chambers 10, 11. The valve 5a cannot be seen here.

The refrigerant exchange arrangement 1 works as follows:

After connecting the refrigerant exchange arrangement 1 to the air-conditioning system 2, the two valves 4a, 5a open. Also the valve 8 opens, so that a mixture of refrigerant and “old” oil reaches the first oil-trapping chamber 10. Here, oil and refrigerant are separated from each other, in that the flow speed of the mixture is reduced so much that the refrigerant can no longer hold the oil. In this case, the oil will lie on the bottom plate 42, and in the gravity direction the refrigerant will lie on top of the oil.

If now the first oil-trapping chamber 10 is heated, as explained below, this will cause the refrigerant to evaporate, while the oil remains liquid, as it has a higher boiling point that is not reached by the heating. Via the pipe 12 and the filter drier 13, the refrigerant gas then reaches the compressor 14. The filter drier 13 removes water from the refrigerant gas. When the total amount of refrigerant gas has left the first oil-trapping chamber 10, the valve 17 opens and the old oil is led to the oil collector 18.

The refrigerant gas is now compressed in the compressor 14, whereby it gets further heated. As during this compression process it is practically unavoidable that oil will get into the refrigerant again, the compressed refrigerant gas will be led via the pipe 15 to the second oil-trapping chamber 11. Here, the oil will be separated from the refrigerant gas. From the bottom of the second oil-trapping chamber 11 it is led via the valve 20 back to the compressor 14.

The refrigerant that is now free of oil and under a certain pressure can basically only escape from the second oil-trapping chamber 11 via the gas path 50, which is formed between the insert 48 and the dividing wall 43. The hot refrigerant gas flowing through the gas path 50 transfers its heat via the dividing wall 43 to the first oil-trapping chamber 10, as mentioned above, in order to evaporate the refrigerant being in the first oil-trapping chamber 10.

The refrigerant, which still has an increased temperature after having passed the gas path 50, is cooled in the condenser and dried in the filter drier 25. After that, it is led to the refrigerant collector 26.

As soon as the refrigerant has been removed from the air-conditioning system 2, the refrigerant exchange arrangement 1 can be operated as follows:

If a replacement of some components of the air-conditioning system 2 is required, it can be made now.

All valve arrangements 6, 27, 30, 33, 38 are closed. Only the two valves 4a, 5a, which connect the main pipe 3 to the air-conditioning system 2, remain open.

Then, the valve 31 of the third valve arrangement 30 is opened, and the vacuum pump 32 is activated. The vacuum pump 32 generates a vacuum in the air-conditioning system 2 of approximately 0.8 bar. Of course, also other vacuum values are possible. It is tested, if the vacuum can be maintained after turning off the vacuum pump 32. If, after a predetermined test period, the vacuum has not changed by more than a predetermined value, it is assumed that the air-conditioning system 2 is tight, and the refilling can start.

If the vacuum has subsided, this is a sign that the air-conditioning system 2 is not tight.

If it is assumed that a leakage exists, the fourth valve arrangement 33 is opened. Due to the vacuum, a marking substance is sucked in from the marking substance source 36. When, then, the second valve arrangement 27 is opened, the marking substance mixes with the refrigerant and flows through the air-conditioning system 2. The marking substance will penetrate through spots causing a leakage. Thus, these spots can be identified and the leakages can be remedied.

When the leakages have been remedied or when from the beginning no leakages have existed, a vacuum is generated again, or the vacuum still exists. In this case, the fifth valve arrangement 38 is opened, so that new oil from the oil reservoir 37 is sucked into the main pipe 3. When, then, the second valve arrangement 27 is opened, the new oil mixes with the refrigerant and flows into the air-conditioning system 2.

Due to the simple design of the oil-trapping unit 7, the refrigerant exchange arrangement 1 is extremely easy to service. If, for service purposes, the oil-trapping unit 7 has to be dismounted, only four screws have to be loosened. Then, the covering plate 44 can be removed, so that the two oil-trapping chambers 10, 11 are accessible. The insert 38 can be removed from the second oil-trapping chamber 11 and be cleaned. The remounting is made in the reverse order and is equally simple.

While the present invention has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this invention may be made without departing from the spirit and scope of the present invention.

Claims

1-15. (canceled)

16. A refrigerant exchange arrangement with a first oil-trapping chamber and a second oil-trapping chamber, the second oil-trapping chamber being located inside the first oil-trapping chamber, wherein a gas path out of the second oil-trapping chamber is limited by a wall of the first oil-trapping chamber and that an insert is arranged in the second oil-trapping chamber, which limits the gas path together with the wall of the first oil-trapping chamber.

17. The refrigerant exchange arrangement according to claim 16, wherein the outside of the insert has at least one spirally shaped groove.

18. The refrigerant exchange arrangement according to claim 16, wherein the insert is made of a plastic material.

19. The refrigerant exchange arrangement according to claim 16, wherein at least one outer wall of the first oil-trapping chamber is made in one piece with a bottom plate.

20. The refrigerant exchange arrangement according to claim 19, wherein a dividing wall between the first oil-trapping chamber and the second oil-trapping chamber is made in one piece with the bottom plate.

21. The refrigerant exchange arrangement according to claim 20, wherein a covering plate is arranged on the side of the first oil-trapping chamber, which is opposite to the bottom plate, the dividing wall engaging said covering plate.

22. The refrigerant exchange arrangement according to claim 21, wherein the insert engages the covering plate.

23. The refrigerant exchange arrangement according to claim 21, wherein the outer wall has a fixing flange in the area of the covering plate.

24. The refrigerant exchange arrangement according to claim 16, wherein the outlet of the second oil-trapping chamber is connected to a refrigerant collector.

25. The refrigerant exchange arrangement according to claim 24, wherein a main pipe is connected via a first valve arrangement to the first oil-trapping chamber and via a second valve arrangement to the refrigerant collector, the main pipe having at least one outer connection.

26. The refrigerant exchange arrangement according to claim 25, wherein the main pipe is connected to a vacuum pump via a third valve arrangement.

27. The refrigerant exchange arrangement according to claim 25, wherein the main pipe is connected via a fourth valve arrangement to a marking substance source.

28. The refrigerant exchange arrangement according to claim 25, wherein the main pipe is connected via a fifth valve arrangement to an oil reservoir.