GB2346681A

GB2346681A - Refrigerating circuit

Info

Publication number: GB2346681A
Application number: GB0002102A
Authority: GB
Inventors: Joerg Kirchner; Juergen Schenk; Monika Knabe; Juergen Voigt
Original assignee: Kenmore Thermokaelte GmbH
Current assignee: Kenmore Thermokaelte GmbH
Priority date: 1999-02-10
Filing date: 2000-01-28
Publication date: 2000-08-16
Anticipated expiration: 2020-01-28
Also published as: ITMI20000195A1; HU222857B1; HUP0000133A3; IT1316353B1; GB2346681B; ES2156785B1; ITMI20000195A0; GB0002102D0; ES2156785A1; HU0000133D0; TR200000218A2; HUP0000133A2; TR200000218A3

Abstract

A refrigerating circuit comprises a condenser and an evaporator, wherein shaped bodies (9, 9a) of drying agent are arranged within a component (6), which carries liquid refrigerant, of the circuit and are so adapted to the internal geometric shape of the respective component as to filter residual moisture from throughflowing refrigerant. Each body (9) may be of a molecular sieve. The bodies (9) may be tubular or cylindrical (11) in shape. The bodies (9) may be moulded into shape. A fine-mesh sieve (15), which may be sintered and acts as a filter, holds the bodies (9) in place, The bodies (9) may be attached to a wire to help in replacement of a body.

Description

REFRIGERATING CIRCUIT The present invention relates to a refrigerating circuit.

The refrigerant drying path, which is incorporated in a closed refrigerating circuit, and which is usually designed as a filter at the same time and conducts liquid refrigerant, has the task of extracting any residual moisture and possible fine dirt particles and abrasion particles of the drying means from the liquid refrigerant in order to ensure dryness and stability of the circuit.

In the case of known refrigerating circuits, the refrigerant drying path is formed by a separate drier or filter-drier, which is incorporated into the closed circuit by soldering or by a fluid-tight connection and arranged, with respect to the flow direction of the liquid refrigerant, upstream of a flow throttle point, preferably a capillary or expansion valve.

These driers or filter-driers essentially consist of a housing in which a drying means and a sieve, which is arranged downstream of the drying means in the flow direction of the refrigerant, are arranged. One end of the housing is matched to the diameter of the pipe of the condenser and the other end is matched to the diameter of a capillary or an expansion valve connected thereto.

This mode of construction of the drier, which preferably finds application in a refrigerating circuit for a refrigerating and freezing appliance with a rear wall condenser, is expensive to produce due to the necessary design of the housing with increased diameter and with consequent narrowing at the inlet and outlet ends to match,-espectively, the diameter of the pipe of the rear wall condenser and the diameter of the capillary. Moreover, the connecting of the drier with the condenser pipe and the capillary is an expensive step which has to be carried out with particular care in order to avoid impairment of the circuit.

In the case of driers of that kind, the inlet end and the outlet end must be closed securely after manufacture and until assembly in order that an ingress of air moisture or small dirt particles can be avoided so as to ensure full effectiveness of the drier after incorporation into the refrigerating circuit. The ingress of small dirt particles and moisture into the drier before incorporation into the circuit would significantly impair the dryness and stability of the circuit.

In DE 297 14 545 U1 there is disclosed a refrigerating circuit in which the drying means is introduced in the form of loose material into an enlargement of the pipe, which carries the liquid refrigerant, of the rear wall condenser, which material is separated by a sieve from the adjoining capillary, or is inserted in the form of a filter cartridge, which is to be filled with drying means, with a filter sieve. Although additional incorporation of a drier can be dispensed with in the case of a refrigerating circuit of that kind and the disadvantages connected therewith can almost be excluded, the enlargement of the pipe of the rear wall condenser is expensive and the production effort and the care during the assembly, for example during soldering-on of the capillary, continue to be required, so that economy could not be substantially improved with the application of this refrigerating circuit.

In known refrigerating circuits of larger stationary refrigerating plant, the filter drier, which is additionally incorporated into the refrigerating circuit, consists of a housing containing solid bodies of filter drying agent, which are produced in the form of pressed sintered bodies of filter drying agent. These solid bodies, which are also known as filter drying cartridges, are clamped together by special fastening equipment in such a manner that they are flowed through in succession by refrigerant within the housing of the filter drier. The fastening equipment, by which the filter drying cartridges must be connected together and mounted within the housing, are relatively expensive. The length of this fastening equipment must be matched to the number of the filter drying cartridges used. Consequently, an associated fastening equipment must be kept in reserve for each filter drier of a certain capacity.

However, it also has to be made certain with these driers that, up to the time of assembly into the refrigerating circuit, the drier is protected against ingress of moisture and dirt particles by closing of the entry and exit openings.

A refrigerating circuit for an air-conditioning plant with a condenser, in which drying means equipment in the form of a filter cartridge is arranged to be integrated within the condenser in the flow path of the refrigerant, is known from DE 198 00 739. This filter cartridge consists of a filter drying means which, similarly as for a drier, is introduced into a cylindrical projection of a housing which is capable of being screwed into place. The thusformed drying equipment is inserted into the liquid refrigerant flow of a collecting pipe of the condenser. This refrigerating circuit, due to the additionally insertable drying equipment, has almost the same disadvantages as outlined for the preceding refrigerant circuits. Due to the formation of the condenser with deflecting stages, the length of the drying equipment and thereby the surface of the drying means flowed across by liquid refrigerant is limite, whereby the dryness and the stabiiity of the circuit can be impaired.

There is therefore a need to improve such refrigerating circuits in the manner that the effectiveness of the circuit may be able to be increased by improved utilisation of a component carrying liquid refrigerant, and a separate component, which is to be incorporated into the circuit, with drying or filtering function can be dispensed with so that manufacturing and assembly costs can be reduced.

According to the present invention there is provided a refrigerating circuit with a condenser and an evaporator, characterised in that shaped bodies of drying agent are arranged within the components of the circuit, which carry liquid refrigerant, and are adapted to the internal geometric shape of the respective components. It is ensured by this construction of the refrigerating circuit that a drying of the liquid refrigerant can take place during the flow through the components which are flowed through by liquid refrigerant in the circuit.

Consequently, it is possible to dispense with an additional drier without the dryness and stability of the circuit, which are critical magnitudes for the stability and performance of the associated refrigerating system, being impaired. Consequently, the costs for construction of the refrigerating circuit can be reduced by the omission of a separate drier and the refrigerating circuit can be operated more economically.

Preferably, a sieve is arranged in the component, which carries liquid refrigerant, in flow direction of the refrigerant behind the moulded body. This sieve can advantageously be a sintered body. It is ensured by this sieve that, on the one hand, the moulded bodies are fixed in position in flow direction of the refrigerant and, on the other hand, possible solid particles, which are entrained by the refrigerant flow, are filtered out of the refrigerant in order to prevent clogging of a throttle point, for example a capillary or an expansion valve.

In a further preferred embodiment, the moulded bodies are, in the case of a component bent in meander shape, inserted into a straight region of the component. Thus, in the case of a component constructed as rear wall condenser, this region can be that portion of the component in flow direction of the refrigerant which is adjoined by the capillary or the expansion valve. Thereby, moulded rods can be inserted without problems one after the other into the pipe of the rear wall condenser, whereby the assembly of the refrigerating circuit is simplifie substantially. Moreover, such a manner of construction of the circuit leads to a compact constructional shape which is advantageous for transportation.

Preferably, also, the moulded body consists of an elongate moulded part, the diameter of which is greater than half the interna diameter of the component. The external outline of the moulded body can be freely selectable even when several moulded bodies are pushed one after the other into the component carrying liquid refrigerant. In this manner, it can be ensured that the greatest possible area of the moulded bodies of drying agent is flowed around by the liquid refrigerant without having to fear that, for example due to the refrigerant flowing past, the pushed-in moulded bodies overlie one another at their longitudinal sides, which could lead to disturbances in the stability of the circuit.

It is advantageous for larger refrigerating circuits if the moulded bodies each consist of a moulded part of hollow cylindrical shape having a wall thickness which is less than half the interna diameter of the component and an external diameter which is smaller than the interna diameter of the component. Thereby, the area of the moulded bodies flowed around by refrigerant can be increased in the case of systems with a greater volume flow of refrigerant. Due to the proposed dependence of the wall thickness of the hollow cylindrical moulded body on the intemal diameter of the component, it can be made certain that the drying agent used for the forming of the moulded bodies is utilise for the drying function and thereby for the drying and stability of the circuit.

It is also advantageous if the connection between the throttle point, for example expansion valve, and the component is detachable, especially in the case of larger refrigerating systems, so that the moulded bodies are exchangeable. It is recommended for this purpose to provide the moulded bodies with a thin wire so that they can be easily drawn out of the circuit for purposes of renewal. Thus, larger stationary refrigerating systems can be equipped with a refrigerating circuit embodying the invention, particularly systems likely to have a service life far beyond the service life of the moulded bodies.

An embodiment of the invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a schematic view of a refrigerating circuit embodying the invention, with a rear wall condenser ; Fig. 2 is a longitudinal section view, to an enlarged scale, of a component of the circuit with included shaped bodies of drying agent; Fig. 3 is a cross-section, to a further enlarged scale of the component with one of the shaped bodies, of solid form; and Fig. 4 is a cross-section similar to Fig. 3, but showing a shaped body of hollow cylindrical form.

Referring now to the drawings, there is shown the refrigerating circuit of a refrigerating and/or freezing appliance essentially comprising a throttle, for example a capillary 3, an evaporator 2, a compressor 4 and a condenser 1, which is constructed as a rear wall condenser.

As shown in Fig. 1, the condenser 1 and the evaporator 2 each consist of a pipe bent into meander shape, denoted in the following as components 5 and 6. Each pipe is securely connected, for example by a soldered connection, in liquid-tight and air-tight manner at one end with the compressor 4 and at the other end with the capillary 3.

Loosely arranged in the component 6, which carrjes liquid refrigerant, are one or more shaped or moulded bodies 9, 9a or 11 of a drying agent, as shown in Fig. 2. These bodies are flowed around or through and around, whilst in flotation, by the liquid refrigerant during flow thereof through the component 6. In that case, residual moisture is extracted from the liquid refrigerant, so that the dryness and stability of the circuit are ensured and a high degree of dynamic drying is achieved.

A fine-mesh sieve 15, which arrests the bodies pushed into the component 6 in the flow direction 14a of the refrigerant, is pressed in behind the bodies in the flow direction. The sieve 15 also filters possible contaminants, which can consist of abrasion particles of the bodies 9,9a or 11 from the refrigerant. It is advantageous if the sieve 15 is a sintered body which can, as is known, be manufactured with a very small pore size and is thereby capable of filtering out even small contaminants from the refrigerant so that a risk of clogging of the capillary 3 can be largely excluded.

The bodies 9,9a or 11 consist of elongate cylindrical moulded pieces, the external diameter 10 of which is greater than half the interna diameter 8 of the component 6, but smaller than the interna diameter 8 of the component 6. It is advantageous if the extemal diameter 10 is less than 85% of the intemal diameter 8 of the component 6. In this manner, the bodies are prevented from sliding past one another at their longitudinal sides.

Consequently, a reduction in the contact area of the liquid refrigerant with the bodies or a cross-sectional constriction in the throughflow region can be excluded. At the same time, an adequate free gap between the interna diameter 8 of the component 6 and the external diameter of the bodies is formed for the flowing refrigerant, so that the full effectiveness of the drying function of the bodies is ensured.

In order to increase the contact area of the liquid refrigerant with the drying agent, it is advantageous, particularly in the case of larger refrigerating circuits designed with a greater intemal diameter 8 of the components 6, if bodies 11 of hollow cylindrical shape are used, as shown in Fig. 4. In order that the deployed quantity of drying agent of the bodies can be included completely in the drying of the refrigerant, it is advantageous if the wall thickness 12 of the body 11 is less than half the interna diameter 8 of the component 6. Preferably, the wall thickness 12 should not be greater than 40% of the intemal diameter 8 of the component 6.

The external outline of the bodies 9,9a or 11 can be chosen freely as desired and is not limited to the outlines illustrated in Figs. 3 and 4, provided that the preferred interdependency of the diameters of the component 6 and the bodies is observe. The same applies to the interna outline of the body 11.

Preferably, the drying agent of which the bodies 9,9a or 11 are made consists of a molecular sieve as main component.

In order that, in particular in the case of a large refrigerating system, the circuit has a long service life which as a rule should be greater than the time for saturation of the drying agent of the bodies 9,9a or 11, the connection between the component 6 and the throttle can, for example, be constructed to be detachable so that the bodies are accessible for purpose of exchange. It is recommended for this purpose to provide the bodies with a fine, firmly connected wire, by which the bodies, when due for replacement, can be readily removed from the component 6 after removal of the sieve 15. Appropriate suitable detachable connections can also be provided within the component 6 when the moulded bodies 9,9a or 11 are to be provided in a region of the circuit which does not correspond with the portion 7 of the component 6 at which the throttle directly adjoins, provided that a form of connection is chosen which ensures the dryness and the stability of the circuit.

The possibility also exists of arranging the bodies in other regions of a component carrying a liquid refrigerant. This can, inter alia, contribute to a further improvement in the dryness and stability of the circuit and thereby the dynamic drying.

The flow direction 14, of the gaseous refrigerant in the component 5 of the evaporator 2 is shown in Fig. 1 exclusively for completion of the circuit.

Claims

CLAIMS 1. A refrigerating circuit including a condenser and evaporator and provided with at least one solid body of drying material arranged in a refrigerant flow path of a component part of the circuit, the body being so adapted in shape to the intemal geometric shape of the component part that the drying material of the body has a drying effect on moisture in refrigerant flowing in the component part.
2. A circuit as claimed in claim 1, comprising a filter arranged in the component part downstream of the body or bodies with respect to a given direction of flow of refrigerant along the path.
3. A circuit as claimed in claim 2, wherein the filter is an element of sintered material.
4. A circuit as claimed in any one of the preceding claims, wherein the or each body comprises a molecular sieve.
5. A circuit as claimed in any one of the preceding claims, wherein the component part defines a straight section of the flow path and a curved section of the flow path and the or each body is arranged in the straight section.
6. A circuit as claimed in any one of the preceding claims, wherein the or each body is arranged in a section of the flow path adjoining a throttle point of the circuit.
7. A circuit as claimed in any one of the preceding claims, wherein the or each body is elongate and has an external diameter or width smaller than the diameter or width of the flow cross-section of the path, but greater than half the diameter or width of that crosssection.
8. A circuit as claimed in any one of claims 1 to 6, wherein the or each body is tubular and has a wall thickness less than half the diameter or width of the flow cross-section of the path and an external diameter or width smaller than the diameter or width of that crosssection.
9. A circuit as claimed in claim 7 or claim 8, wherein the or each body has a freely selected extemal outline in cross-section.
10. A circuit as claimed in claim 9, wherein the or each body has a freely selected intemal outline in cross-section.
11. A circuit as claimed in any one of the preceding claims, comprising a plurality of such bodies inserted loosely into the component so as to be disposed one after the other in the flow path.
12. A circuit as claimed in claim 11, wherein the bodies have respectively different external outlines in cross-section.
13. A circuit as claimed in claim 6, wherein the intemal diameter of the section of the flow path adjoining the throttle point is matched to the intemal diameter of the flow point.
14. A circuit as claimed in any one of the preceding claims, comprising connecting means openable to permit removal of the or each body from the flow path.
15. A circuit as claimed in any one of claims 1 to 5, wherein the component part is a component part other than the condenser.
16. A circuit as claimed in any one of claims 1 to 4, wherein the flow path is not straight.
17. A refrigerating circuit substantially as hereinbefore described with reference to the accompanying drawings.
18. Refrigerating apparatus comprising a circuit as claimed in any one of the preceding claims.