EP1853859B1 - Coolant collector comprising a filter/dryer unit - Google Patents

Abstract

Disclosed is a coolant collector ( 1 ) comprising a filter/dryer unit ( 10 ) and an elongate, vertically oriented interior space which is subdivided into an upper area ( 38 ) and a lower area ( 39 ) by means of the filter/dryer unit ( 10 ). A flowing coolant is delivered to the filter/dryer unit ( 10 ) via a pipe ( 7 ). The outlet windows of the filter/dryer unit ( 10 ) are located on the outer circumference thereof which delimits a relatively narrow gap along with the wall ( 3 ) of the receptacle ( 2 ) of the coolant collector ( 1 ). Liquid components drip downwards and accumulate below the filter/dryer unit while gaseous components accumulate primarily above the filter/dryer unit ( 10 ).

Description

The invention relates to a refrigerant collector with filter / dryer unit for refrigeration systems. The refrigerant collector according to the invention is particularly suitable for motor vehicle air conditioning systems and in particular for those which are operated with carbon dioxide as the refrigerant.

Refrigerant collectors are usually traversed by refrigerant, while holding a supply of refrigerant. This buffers lower refrigerant losses of the chiller and different operating conditions of the same. Therefore, there is usually a certain supply of liquid refrigerant in the refrigerant collector. The refrigerant must be dry. If ice forms in unfavorable places in the chiller, this can lead to malfunctions and damage to the chiller. Therefore, refrigeration plants usually have dryers. These are e.g. tubular storage vessels in which a water-absorbing material e.g. a granule is arranged. This is flowed through by the refrigerant. It is important to ensure a sufficiently intimate contact between the refrigerant and the dryer material.

From the US-A-4,457,843 a refrigerant collector is known with a pressure-resistant upright vessel whose wall comprises a bottom and an upper end and includes an interior. Into the interior leads a tube having an arranged in the interior end. The pipe end opens into the interior and can thus supply it with a fluid. Another pipe leading through the upper end into the interior space carries at its lower end a filter / dryer unit located above the floor. In addition, one of the tubes near the bottom may have a U-shaped curvature to which a small aperture provided with a filter is attached. Through this opening fluid can penetrate into the U-tube, for example, to introduce oil into the tube.

In particular, the compressors of CO ₂ refrigeration machines but also the compressors of other refrigerators are relatively sensitive to sucked fluid drops and in particular solid particles. It is therefore desirable to ensure that the refrigerant flow sucked in by the compressors contains in particular no solid particles.

On this basis, it is an object of the invention to provide a unit which solves at least some of the above problems in a technically simple and reliable manner.

This object is achieved with the refrigerant collector with integrated filter / dryer unit according to claim 1:

The refrigerant collector according to the invention is based on a pressure-resistant, upright vessel with wall, bottom and .oberem conclusion, so that a closed interior is enclosed. A first tube leads into the interior and a second tube leads out of the interior. In the interior, a filter / dryer unit is arranged; fed by the tube leading into the interior becomes. The filter / dryer unit is supplied approximately in its center with refrigerant. The filter / dryer unit has at least one, but preferably a plurality of large-area outlets, whose cross section exceeds the cross section of the feeding pipe. The outlets open into the interior of the container, in which thus both oil and liquid refrigerant can collect. The tube leading out of the interior space has an upper open end, which is preferably arranged above the filter / dryer unit. It leads from this point out of the interior. In this case, it is preferably guided in a U-shape around the filter / dryer unit, wherein a lower pipe bend of the pipe leading out of the interior runs directly above the bottom of the vessel. In this area, a suction opening is preferably arranged. The pipe bend undercuts an oil level, which forms in the vessel. As a result, the refrigerant flow leaving the vessel can be metered in via the intake opening and carried along with it. This is desired for lubrication of the connected compressors.

Between the oil level and the filter / dryer unit a partial volume of the interior is limited, in which refrigerant can be present in the liquid phase. The amount of liquid refrigerant may vary depending on the conditions of use of the refrigerator. However, the filter / dryer unit separates the refrigerant level from the upwardly towering open tube end of the tube leading out of the inner space, so that no splashes of refrigerant can get into the open tube end, even if the refrigerant collector when installed in a motor vehicle shaken during heavy driving maneuvers or bumpy roads.

In a preferred embodiment, the wall of the vessel of the refrigerant collector is cylindrical, whereas the bottom of the vessel is rounded. The latter has the advantage that even with small amounts of oil, a sufficiently high oil level can be achieved in order to provide the refrigerant flow with oil. In addition, the vessel shape is particularly pressure-resistant in this way.

The upper end of the vessel is preferably formed flat or slightly rounded, the two tubes side by side into the vessel and lead out of this. Thus, above the filter / dryer unit, an approximately cylindrical vapor dome is formed, in which refrigerant is predominantly in the gaseous phase and can be withdrawn well. The connection of the two side by side preferably parallel to each other oriented tubes is also simple and clear.

Preferably, the filter / dryer unit occupies the entire cross-section of the interior in such a way that it defines only a relatively narrow annular gap with the wall of the vessel. Out of this annular gap, refrigerant with a relatively low flow rate enters the upper area serving as vapor dome. Sloshing movements of the refrigerant level located below the filter / dryer unit hardly lead to liquid refrigerant reaching the area above the filter / dryer unit. This is certainly not the case in view of the preferred height (axial extent) of the filter / dryer unit, which is preferably larger than the diameter thereof.

From the annular gap liquid refrigerant and oil drip down and collect below the Filter / dryer unit. Liquid CO2 floats on the oil level.

In principle, it is possible for the oil collecting under the filter / dryer unit to be withdrawn from the vessel via capillaries or separate lines and to be added to the oil stream. The pipe leading out of the interior can thus lead directly out of the upper steam dome area to the outside. As a simple and robust solution, however, it is preferred to guide the pipe leading out of the interior space both descending and ascending between the wall and the filter / dryer unit and thus to guide the refrigerant sucked up in the steam dome area through the lower pipe bend, where it is is mixed with oil.

The filter / dryer unit preferably has a housing with a flat top and an approximately cylindrical outer periphery. This effectively separates the liquid refrigerant phase from the vapor refrigerant phase. In addition, it offers a sufficiently large interior to accommodate a large desiccant portion.

It has proven to be very advantageous to provide the filter / dryer unit with a conical bottom. The tip of the bottom is preferably located centrally in the housing approximately below the feeding tube. The cone angle is relatively large and is preferably between 120 ° and 170 °. This shape of the bottom has proved to be advantageous both in terms of the forming flow pattern as well as purely practical because it allows a good compaction of the dryer granules when closing the filter / dryer unit. This is especially true when the bottom is inserted into the housing of the filter / dryer unit from below and then, for example, through Locking means is fixed. The dry granules are flowed through substantially radially, wherein the flow rate is low and decreases towards the outside. This allows intimate contact between dry granulate and refrigerant fluid. The low flow rate in the housing of the filter / dryer unit results in a low pressure drop across the refrigerant collector.

Spherical granules are preferably used as dry granules, which provides optimum contact between the refrigerant and the dry granules.

On the inlet side, the filter / dryer unit is provided with an inlet basket having at its periphery and at its bottom outlet openings, e.g. Has holes and slots. The inlet basket allows the introduction of refrigerant fluid into the dry granulate with low pressure drop. At the outlet openings of the housing of the filter / dryer unit, a fine filter is preferably arranged. This is e.g. formed by a fine stainless steel mesh, a stainless steel felt or the like. The mesh size is preferably in the range of 30 microns to 60 microns.

The conical bottom is a prerequisite that leads to a good separation of gaseous and liquid phase. The accumulation of liquid refrigerant and / or oil in the filter / dryer unit is safely avoided. Thus, the dryer granules themselves are kept free of liquids, so that its effectiveness is not affected by oil or liquid refrigerant.

The outlet windows occupy almost the entire outer circumference of the housing of the filter / dryer unit. This further leads to an efficient use of the desiccant through slow flow as well as safe discharge of liquid refrigerant and oil from the housing of the filter / dryer unit.

Further details of advantageous embodiments of the invention are the subject of the drawing, the description or claims.

Figur 1

den Kältemittelsammler in einer perspektivischen Gesamtansicht,

Figur 2

den Kältemittelsammler nach Figur 1 in perspektivischer, vertikal geschnittener Darstellung,

Figur 3

den Kältemittelsammler nach Figur 2 in vertikal geschnittener Darstellung mit zusätzlicher Schnittdarstellung seiner Filter/Trockner-Einheit,

Figur 4

die Filter/Trockner-Einheit des Kältemittelsammlers nach Figur 2 und 3 in vertikal geschnittener Darstellung und

Figur 5

den Kältemittelsammler nach Figur 1 in einer ausschnittsweisen Schnittdarstellung.

In the drawing, an embodiment of the invention is illustrated. Show it:

FIG. 1

the refrigerant collector in a perspective overall view,

FIG. 2

the refrigerant collector after FIG. 1 in perspective, vertically cut representation,

FIG. 3

the refrigerant collector after FIG. 2 in a vertical sectional view with additional sectional view of its filter / dryer unit,

FIG. 4

the filter / dryer unit of the refrigerant collector after FIG. 2 and 3 in a vertical section and

FIG. 5

the refrigerant collector after FIG. 1 in a partial sectional view.

In FIG. 1 is a refrigerant collector 1 illustrated, the outer vessel 2 is formed by an aluminum bottle. This has a cylindrical wall 3 with a substantially flat upper end 4 and a, for example, spherically curved bottom 5. The bottom 5 may be provided with an opening into which a burst plug 6 is screwed. The vessel 2 is closed on all sides to the outside. It can be welded together from two or more parts, with the welds in FIG. 1 not illustrated. Preferably, the vessel 2 without welds and solder joints, ie formed without welding and soldering operation. For this purpose, a hollow cylindrical blank is first produced which already contains the upper end 4. When all the later explained internals are placed in the vessel 2, this is closed to its bottom 5 in a roll forming process or in an alternative forming process to the extent that only the still. To be closed by the stopper 6 opening remains. This manufacturing method makes it possible to produce the vessel 2 even with relatively small wall thicknesses, if it is to be interpreted to very high bursting pressures of, for example, over 200 bar. Otherwise occurring during welding and soldering, occurring due to the temperature stress structural changes of the material are excluded.

Through the conclusion 4 lead two tubes 7, 8 in the enclosed by the vessel 2, from FIG. 2 apparent interior 9 in and out of this. The ends of the tubes 7, 8 enforce the conclusion 4 while parallel to each other. The tube 7 forms the input-side line for introducing refrigerant into the refrigerant collector 1. It leads to a filter / dryer unit 10, which is housed in the inner space 9 in a separate housing 11. The arranged in the interior 9 end 12 of the tube 7 leads to a central terminal, which is on the housing 11, that is, in fact, arranged on its preferably flat upper side 13. The housing 11 also has an approximately cylindrical outer circumference 14, whose diameter is slightly smaller than the inner diameter of the wall 3, so that a slot is formed between the two. To set this defined and to center the housing 11 in the vessel 2, the outer periphery 14 is provided with radially outwardly projecting Abstandshalternasen 15, which are preferably in the form of elongated vertical, ie axially oriented ribs 16, 17, 18 are formed. On the outer periphery 14 are also outlet windows 19, 20, 21, 22, 23 (see FIG. 2 and 3 ) formed from the FIG. 3 apparent interior 24 of the housing 11 open on its entire peripheral surface to the interior 9 of the vessel 3 out. The outlet windows 19 to 23 are separated from each other only by narrow webs, which connect the upper end plate located on the upper side 13 with a lower ring 25 which holds a bottom 26 inserted into the housing 11. The outlet windows 19 to 23 may be provided with a plastic grid, which supports the filter used later explained and protects against manual damage, in particular during assembly.

The bottom 26 is preferably, like the rest of the housing 11, made of plastic. It has an upwardly extending from an annular rim 27 conical bottom portion 28 which has a cone angle of preferably about 130 ° to 150 °. The bottom 26 is preferably connected to the ring 25 via latching means not further illustrated. Its outer edge 29 terminates with the upper edge of the ring 25 or is located just above it.

The outlet windows 19 to 23 are closed by a fine mesh filter. This may be formed for example by a stainless steel mesh, a stainless steel felt or the like. The mesh size is preferably in the range between 30 microns and 60 microns.

In the interior 24 of the housing 11, an inlet basket 31 is arranged, which is preferably integrally connected to the upper end plate of the housing 11. The inlet basket 31 has, for example, a cylindrical shape. At its periphery it is provided with slots 32. In its bottom openings 33 are formed. The slits 32 and openings 33 preferably have a width of not more than 0.8 mm. In any case, however, the width of the slots 32 and openings 33 is less than the grain size of a dry granulate that fills the interior 24. This granulate serves for water absorption.

The housing 11 has groove-like, preferably approximately cylindrical shell-shaped recesses on diametrically opposite or otherwise positioned to each other points, through which the tube 8 extends. It goes from an open, located above the filter / dryer unit 10 end vertically down to the bottom 5 of the vessel 2. The corresponding straight pipe section 34 then passes below the filter / dryer unit 10 in a pipe bend 35, of which starting with a further pipe section 36 again on the filter / dryer unit 10 over to the conclusion 4 and through this leads to the outside. The pipe bend 35 runs just above the bottom 5, as in particular from FIG. 5 evident. At its lowest point, at which the pipe bend 35 is closest to the bottom 5, the pipe bend is provided with a suction bore 37. These has a small diameter and serves to add oil to the refrigerant flowing in the pipe bend 35.

The refrigerant collector 1 described so far operates as follows:

In operation, the vessel 2 is arranged vertically, i. its tubes 7, 8 lead substantially vertically into the interior 9. The central axis of the cylindrical wall is oriented vertically. Through the pipe 7, refrigerant from a refrigerator first flows into the filter / dryer unit dividing the inner space 9 into an upper area 38 serving as a steam dome and a lower area 39 serving as a liquid collector. The refrigerant is usually a three-phase mixture consisting of gaseous refrigerant, liquid refrigerant and liquid oil particles. It first enters the inlet basket 31 and leaves it through the slots 32 and the openings 33 through which it enters the dense packing of the preferably spherical dryer body. In this case, flows through the openings 32 of the bottom portion 28, which redirects the flow radially outward. This results in a relatively uniform, slow flow through the held in the interior 24 dryer pack. Liquid ingredients, i. Liquid refrigerant and oil reach the bottom portion 28 and run on this outward. They exit the filter / dryer unit 10 through the outlet windows 19 to 23 and then run down the ring 25 in the subspace formed by the area 39. Gaseous refrigerant collects, however, predominantly in the region 38 of the interior 9, from which they are withdrawn via the pipe 8.

Under the filter / dryer unit 10 forms a liquid reservoir consisting of oil and liquid refrigerant. Because of the different densities, both divorced from each other. This is especially true when CO _{2 is} used as the refrigerant. It forms above the bottom 5, an oil volume 40 with an oil level 41, on which a liquid refrigerant volume 42 with a refrigerant level 43 rests. The oil level 41 is at least above the suction bore 37. The refrigerant level 43 is at least below the edge 29, but preferably below the ring 25th

The existing in the region 38 vapor refrigerant flows through the pipe section 34 and the pipe bend 35, where it takes along via the suction bore 37 oil. The suction bore 37 may also be considered a drainage bore, which limits the entry of oil into the tube 8 to a desired low level. If necessary, several such holes can be provided. In addition, a filter, for example in the form of a metal mesh, metal felt or the like may be arranged between the pipe bend 35 and the bursting plug 6.

The filter / dryer unit 10 causes not only a drying of the refrigerant but at the same time such an effective subdivision of the interior 9 that no splashes of the optionally boiling or sloshing by external movement surface of the refrigerant volume 42 into the open end of the pipe section 34. It is created in this way a simple, combined refrigerant collector with integrated filter / dryer unit 10.

A refrigerant receiver 1 with filter / dryer unit 10 has an elongate, vertically oriented interior, which is subdivided by the filter / dryer unit 10 into an upper area 38 and a lower area 39. Inflowing refrigerant is through a pipe 7 of the Filter / dryer unit 10 which has its outlet window at its outer periphery, which defines a relatively narrow gap with the wall 3 of the vessel 2 of the refrigerant collector 1. Liquid components drip down and collect below the filter / dryer unit. Gaseous components accumulate predominantly above the filter / dryer unit 10.

Claims (19)

1. Coolant collector (1) comprising
   a pressure-resistant upright receptacle (2) having a wall (3), a bottom (5) and an upper closure (6) which enclose an interior space (9);
   a pipe (7) leading into an interior space (9) that has an end (12) located in the interior space (9);
   a filter/dryer unit (10) that is connected to the end (12) of the pipe (7) leading into the interior space (9) and that is located with a distance to and above the bottom (5); and, a pipe (8) leading out of the interior space (9) and having an open end located in the interior space (9) above the filter/dryer unit (10), characterized in that
   the filter/dryer unit (10) has outlet windows (19, 20, 21, 22, 23) on its outer circumference.
2. Coolant collector in accordance with Claim 1, characterized in that the pipe (8) leading out of the interior space (9) extends from its open end to a pipe bend (35) located on the bottom (5) and, ascending therefrom, from the receptacle (2), wherein the pipe bend (35) is provided with at least one suction opening (37).
3. Coolant collector in accordance with Claim 1, characterized in that the wall (3) of the receptacle (2) is cylindrical.
4. Coolant collector in accordance with Claim 1, characterized in that the bottom (5) of the receptacle (2) is rounded.
5. Coolant collector in accordance with Claim 1, characterized in that the upper closure (4) of the receptacle (2) is flat, and that the two pipes (7, 8) lead next to each other into or out of the receptacle (2).
6. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) takes up the entire cross-section of the interior space (9) and defines an annular gap with the wall.
7. Coolant collector in accordance with Claim 1, characterized in that the pipe (8) leading out of the interior space (9) is guided - as it ascends, as well as it descends - between the wall (3) and the filter/dryer unit (10).
8. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) comprises a housing (11) having a flat surface (13) and having an approximately cylindrical outer circumference (14), from which extend spacer projections (15) toward the wall in order to abut against said wall.
9. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) has a conical bottom (26).
10. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) has, on its upper side (13), a central connection which is connected to the pipe (7) that leads into the interior space (24).
11. Coolant collector in accordance with Claim 10, characterized in that the filter/dryer unit (10) encloses a receiving space (24) in which an inlet basket (31) having inlet openings (32, 33) is arranged, said inlet basked directly adjoining the central connection.
12. Coolant collector in accordance with Claim 11, characterized in that the inlet openings in the filter/dryer unit (10) are configured as holes (33) or as slits (32) having a width that is not greater than the grain size of the dryer granulate.
13. Coolant collector in accordance with Claim 1, characterized in that the outlet windows (19, 20, 21, 22, 23) in the filter/dryer unit (10) take up almost the entire outer circumference of the filter/dryer unit (10).
14. Coolant collector in accordance with Claim 1, characterized in that the outlet windows (19, 20, 21, 22, 23) of the filter/dryer unit (10) are provided with a filter (30).
15. Coolant collector in accordance with Claim 1, characterized in that the filter (30) of the filter/dryer unit (10) consists of a fine-mesh stainless steel net.
16. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) comprises a housing (11) made of plastic material.
17. Coolant collector in accordance with Claim 16, characterized in that the filter/dryer unit (10) has a bottom that is locked to the remaining housing (11).
18. Coolant collector in accordance with Claim 1, characterized in that the filter/dryer unit (10) is arranged at approximately half the height of the interior space (9) or above.
19. Coolant collector in accordance with Claim 2, characterized in that the suction opening (37) is located on the underside of the pipe bend (35) facing the bottom (5).

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