EP0563718A1 - Refrigeration device for refrigerators - Google Patents

Abstract

The invention relates to a refrigeration device for refrigerators with an evaporator, a suction line for conducting off the evaporated refrigerant, a compressor for drawing in and compressing the refrigerant, a liquefier as well as a capillary throttling pipe (7) for the pressure relief of the liquefied refrigerant and its supply to the evaporator. The evaporator-side end (10) of the capillary throttling pipe (7) is provided with a longitudinal section which is designed as a calming section. The calming section has, in relation to the constant inner diameter (Di) of the preceding length (L) of the capillary throttling pipe (7), a greater inner diameter (Di,g). The length of the calming section is matched in such a manner that the turbulence arising at the transition from the smaller diameter (Di) to the greater diameter (Di,g) becomes an essentially calmed laminar flow. In this manner, it is ensured that the injection noises are reduced considerably and the capillary throttling pipe (7) can be made considerably shorter than previously conventional. <IMAGE>

Description

The invention relates to a refrigeration device for refrigerators or the like with a suction line for the conveyance of a vaporous refrigerant from an evaporator to a compressor and a capillary throttle tube arranged partially within the suction line for the expansion of the liquid refrigerant and its feed line to the evaporator.

From DE-PS 12 42 646 a generic refrigeration device for refrigerators is known. Such a refrigeration device essentially comprises a plate evaporator consisting of interconnected sheets, a suction line for discharging the evaporated refrigerant, a compressor for drawing in and compressing the refrigerant, a condenser and a capillary throttle tube for expanding the liquefied refrigerant and its feed line to the evaporator.

Such refrigeration devices have long been used in refrigerators to extract heat from their contents and thus reduce the temperature prevailing in the refrigerator. The low-pressure refrigerant is evaporated in the evaporator. Evaporation reduces the temperature in the cold room. The compressor sucks in the steam and compresses it to a higher pressure. The steam releases its heat to the outside in the downstream condenser. The refrigerant is liquefied by the interaction of increased pressure and heat emission. As the last phase, the liquid refrigerant in the capillary throttle tube is expanded to the lower pressure and gets back into the evaporator.

Until now, it was common to use capillary throttle tubes with a very small inside diameter. This had the advantage that the capillary throttle tube could be made short, which ensured good handling and inexpensive execution. However, the noises had a disadvantageous effect when the refrigerant was injected from the capillary throttle tube into the evaporator.

According to a further proposal, the noise emission was then remedied by increasing the inside diameter of the capillary throttle tubes. However, this was associated with the disadvantageous consequence that the capillary throttle tubes had to be made very long for the same flow rate of the refrigerant.

In order to ensure, for example, a volume flow Q of 5 l / min at a pressure p of 10 bar, the capillary throttle tube with an inner diameter D _i of 0.6 mm had to have a length L _K of 2000 mm. When the internal diameter D _{i was increased} from 0.6 mm to 0.8 mm, the capillary throttle tubes had to be 5500 mm long under otherwise identical conditions.

Such extremely long capillary chokes were difficult to handle. The long free end had to be rolled up. The assembly of the capillary throttle tube was also complex. In addition, the long capillary throttle tubes were expensive due to the large amount of material used.

Based on the features described in the preamble of claim 1, the invention is based on the object of improving such a refrigeration device in such a way that the material used for the capillary throttle tube can be markedly reduced while reducing the injection noise.

This object is achieved according to the invention in the features listed in the characterizing part of claim 1.

Then the end of the capillary throttle tube on the evaporator side is now provided with a length section which is designed as a calming section. The calming section has a larger inner diameter compared to the constant inner diameter of the previous length of the capillary throttle tube. The length of the calming section is adjusted in such a way that the turbulence occurring during the transition from the smaller inside diameter to the larger inside diameter changes into an essentially calmed laminar flow.

In this way, the injection noise can be reduced to the same values as would otherwise only be achievable over the entire length if the capillary throttle tube was designed with a larger diameter. This has the consequence that the capillary throttle tubes can be made much shorter than usual, which also improves their manageability. The material savings mean that the capillary throttle tubes are also available at a significantly lower cost than in the prior art. Since the capillary throttle tubes are mass products, this advantage is particularly noticeable from an economic point of view.

The enlargement of the inner diameter in the area of the calming section can be carried out with different manufacturing processes. For example, drawing, pressing, punching, rolling or rolling are conceivable.

It is possible to widen the area of the calming section afterwards. However, a capillary throttle tube with a larger inner diameter can also be used and this can subsequently be narrowed to the area outside the calming section.

It is also possible to increase the inner diameter of the calming section in several stages.

According to the features of claim 2, the length section of the capillary throttle tube having the calming section can be designed such that it continuously increases from the smaller inner diameter to the larger inner diameter. A laminar flow pattern is thereby achieved.

The transition from the length section of the capillary throttle tube with the smaller inside diameter to the calming section can be step-shaped with sharp-edged or rounded edges or else conical.

According to the features of claim 5, the capillary throttle tube is rolled up helically. This leads to a space-saving, flexible design.

For the introduction of the capillary throttle tube into the suction line, this has a capillary throttle tube insertion section according to the features of claim 6. The outer diameter of the suction line in the area of the capillary throttle tube insertion section is increased by approximately the outer diameter of the capillary throttle tube. This is a simple introduction in terms of production technology of the capillary throttle tube in the suction line. The capillary throttle tube is guided into the suction line and fixed via the capillary throttle tube insertion section. In this way, a refrigerant-tight seal to the outside is guaranteed.

To hold the capillary throttle tube and compensate for linear expansion, the capillary throttle tube is guided at least once helically around the suction line in front of the capillary throttle tube insertion section in accordance with the features of claim 8. Damage to the installation of the cooling device in the cooling units is also prevented in this way.

A further possibility of fixing the capillary throttle tube to the suction line before it is introduced into the suction line consists, according to the features of claim 9, in a connection which is produced from plastic by means of a shrink tube. The shrink tube is pulled over the capillary throttle tube and the suction line and shrunk by heating, which creates the positionally stable connection.

Fig. 1

in der Ansicht, teilweise im vertikalen Längsschnitt den Ausschnitt eines Verdampfers für ein Kältemittel mit einer Saugleitung und einem Kapillardrosselrohr;

Fig. 2

in vergrößerter Darstellung den Ausschnitt II der Fig. 1;

Fig. 3

einen Ausschnitt des verdampferseitigen Endes eines Kapillardrosselrohrs mit stufenförmigem Übergang zu einer Beruhigungsstrecke;

Fig. 4

einen Ausschnitt des verdampferseitigen Endes eines Kapillardrosselrohrs mit konischem Übergang zu einer Beruhigungsstrecke;

Fig. 5

einen Ausschnitt des verdampferseitigen Endes eines Kapillardrosselrohrs mit einem sich kontinuierlich vergrößernden Innendurchmesser und

Fig. 6

einen Abschnitt des verdampferseitigen Endes eines Kapillardrosselrohrs mit zweifach gestuftem Übergang zu einer Beruhigungsstrecke.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings. Show it:

Fig. 1

in the view, partially in vertical longitudinal section, the section of an evaporator for a refrigerant with a suction line and a capillary throttle tube;

Fig. 2

in an enlarged view the section II of Fig. 1;

Fig. 3

a section of the evaporator-side end of a capillary throttle tube with a step-like transition to a calming section;

Fig. 4

a section of the evaporator-side end of a capillary throttle tube with a conical transition to a calming section;

Fig. 5

a section of the evaporator-side end of a capillary throttle tube with a continuously increasing inner diameter and

Fig. 6

a section of the evaporator-side end of a capillary throttle tube with a double step transition to a calming section.

1 shows a plate evaporator, in particular for refrigerators. The plate evaporator 1 consists of two sheets 2, which are connected to one another in a known manner. At least one of the sheets 2 is provided with internal features 3, which form 2 channels 4 in the plate evaporator 1 after the sheets have been connected.

The plate evaporator 1 has a connection opening 5 through which both a suction line 6 leading to the compressor (not shown) for the vaporous refrigerant and a capillary throttle tube 7 for conveying the liquid refrigerant enter the plate evaporator 1. At the connection opening 5 of the plate evaporator 1 there is a tubular suction channel 8 for the vaporous refrigerant at. The suction channel 8 narrows at a sealing section 9 to the outer diameter D _{a of} the capillary throttle tube 7. Behind the sealing section 9, the suction channel 8 widens to the evaporator channel 4a, into which the capillary throttle tube 7 opens with an end section 10.

The evaporator-side end section 10 of the capillary throttle tube 7 has a length section L _{B designed} as a calming section (FIG. 2). In the entire length section L of the capillary throttle tube 7 before the calming section, the capillary throttle tube 7 has a constant diameter D _i . In contrast, the capillary throttle tube 7 in the length section L _B has an internal diameter D _{i, g that is} larger than the constant diameter D _{i of} the preceding length section L. The suction channel 8 and the capillary throttle tube 7 are connected in a refrigerant-tight manner on the sealing section 9.

It can also be seen from FIG. 1 that the suction line 6 has a capillary throttle tube insertion section 11. In the area of the capillary throttle tube insertion section 11, the suction line 6 is provided with a clear cross-section D _k which is larger by the outer diameter D _{a of} the capillary throttle tube 7 than its remaining length range L _S. At the end face 12 of the capillary throttle tube insertion section 11, the capillary throttle tube 7 is guided into the suction line 6. In front of the capillary throttle tube insertion section 11, the capillary throttle tube 7 is laid on a length section E parallel to the suction line 6. Following the length section E, the capillary throttle tube 7 has three helical windings 13 around the suction line 6. In the further course, the capillary throttle tube 7 is again provided on a section T with helical turns 14. This ensures a space-saving way of laying the capillary throttle tube 7.

FIG. 3 shows an embodiment of a length section L _B1 with an evaporator-side end section 10a of a capillary throttle tube 7 with a transition 15, which takes place in steps with sharp-edged corners. At the transition 15, the inner diameter D _{i of} the capillary throttle tube 7 widens to the larger inner diameter D _{i, g of} the length section L _B1 .

The embodiment in FIG. 4 of the length section L _B comprising a calming section corresponds to that in FIG. 2. The end section 10 of a capillary throttle tube 7 is shown with a transition 16 which tapers from the inside diameter D _{i of} the capillary throttle tube 7 to the larger inside diameter D _{i, g} expanded. The transition 16 takes place on a short length L _E.

FIG. 5 discloses a length section L _B2 having a calming section with an end section 10b of a capillary throttle tube 7, in which the inside diameter D _i continuously expands to the larger inside diameter D _{i, g} . The course of the calming section is optimized in terms of flow technology and has an inner contour adapted to the characteristics of the refrigerant with regard to at least the pressure and speed conditions.

FIG. 6 shows a length section L _{B3 designed} as a calming section with an end section 10c of a capillary throttle tube 7 with a transition 17 which takes place in two stages 18, 19. The length section L _B3 is divided into the length sections L₁ and L₂. At stage 18, the inside diameter D _{i of} the capillary throttle tube 7 initially widens to a larger inside diameter D _{i, 1} in the length section L ₁ . At the next stage 19, the inner diameter D _{i, 1} expands to the inner diameter D _{i, g} .

List of reference symbols

1

Plate evaporator

2nd

sheet

3rd

Expression

4th

Evaporator channel
4a - evaporator channel

5

Connection opening

6

Suction line

7

Capillary throttle tube

8th

Suction channel

9

Sealing section

10th

End section
10a - end section
10b - end section
10c - end section

11

Capillary throttle tube insertion section

12

Face

13

Swirl

14

Swirl

15

crossing

16

crossing

17th

crossing

18th

step

19th

step

D _a

Outer diameter of 7

D _i

Inner diameter of 7

D _{i, g}

enlarged inner diameter v. 7

D _k

Cross section v. 11

E

Length section

L

Capillary throttle tube length

L _B

Length section
L _B1 - length section
L _B2 - length section
L _B3 - length section

L _E

Length piece

L _S

Length range

L₁

Length section

L₂

Length section

T

Section

Claims (9)

Refrigeration device for refrigerators or the like with a suction line (6) for the conveyance of a vaporous refrigerant from an evaporator (1) to a compressor and a capillary throttle tube (7) arranged partially within the suction line (6) for the expansion of the liquid refrigerant and its feed line to Evaporator (1), characterized in that the capillary throttle tube (7) has in the region of its end (10, 10a-c) on the evaporator side at least one length section (L _B , L _B1 , L _B2 , L _B3 ) which has a calming section, compared to the constant inside diameter (D _i ) of the preceding length section (L) has a larger inside diameter (D _{i, g} ). Refrigerating device according to claim 1, characterized in that the capillary throttle tube (7) has a length section (L _B2 ) with a continuously increasing inner diameter (D _{i, g} ). Refrigerating device according to claim 1, characterized in that the transition (15) of the length section (L) having a constant inner diameter (D _i ) to the length section (L _B , L _B3 ) designed as a calming section is step-shaped. Refrigeration device according to claim 1, characterized in that the transition (16) of the length section (L) having a constant inner diameter (D _i ) to the length section (L _B ) designed as a calming section is conical. Refrigerating device according to claim 1, characterized in that the capillary throttle tube (7) is provided with helical windings (14) in the region of the length section (L) having a constant inner diameter (D _i ) on a section (T). Refrigerating device according to claim 1, characterized in that the suction line (6) has a capillary throttle tube insertion section (11) which has a clear cross section (D _K ) which is approximately larger by the outer diameter (D _a ) of the capillary throttle tube (7) than in its remaining length range ( L _S ). Refrigeration device according to claim 1 or 6, characterized in that the capillary throttle tube (7) is guided in a refrigerant-tight manner into the suction line (6) via the capillary throttle tube insertion section (11). Refrigerating device according to claim 1, characterized in that the capillary throttle tube (7) is guided at least once helically around the suction line (6) in front of the capillary throttle tube insertion section (11). Refrigerating device according to claim 1, characterized in that the capillary throttle tube (7) can be fixed in front of the capillary throttle tube insertion section (11) by means of a shrink tube on the suction line (6).

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