A heat exchanger device
The invention relates to a heat exchanger device including a plate heat exchanger having a plate package of heat transfer plates. Between the plates there are first passages (18) for a heat transfer medium and second passages (19) for a cooling agent. Porthole channels (21 and 22) communicate with the first passages. Porthole channels (23 and 34) communicate with the second passages. The porthole channel (21) forms at least a part of an inlet channel (31) for the heat transfer medium. The porthole channel (22) forms at least a part of an outlet channel (32) for the heat transfer medium. The porthole channel (23) forms a part of an inlet channel (33) for the cooling agent. The porthole channel (24) forms a part of an outlet channel (34) for the cooling agent. A conduit (5) extends to the inlet channel (33) for supplying the cooling agent to the second passages. The conduit includes a conduit portion (6) extending into and out of the outlet channel (34) for the heat exchanger between the cooling agent in the conduit portion and the cooling in the outlet channel.
The present invention refers to a heat exchanger device including a plate heat exchanger, wherein the plate heat ex-changer includes a plate package of heat transfer plates, which are arranged to form between the plates first passages for a heat transfer medium to be cooled and second passages for a cooling agent. The plate package includes a first porthole channel and a second porthole channel, which communicate with the first passages, and a third porthole channel and a fourth porthole channel, which communicate with the second passages. The first porthole channel forms at least a part of an inlet channel for supplying the heat transfer medium to the plate heat exchanger. The second porthole channel forms at least a part of an outlet channel for discharging the heat transfer medium from the plate heat exchanger. The third porthole channel forms at least a part of an inlet channel for supplying the cooling agent to the plate heat exchanger. The fourth porthole channel forms at least a part of an outlet channel for discharging the cooling agent from the plate heat exchanger. The heat exchanger device includes a conduit extending into the inlet channel for the cooling agent for supplying the cooling agent to the third porthole channel and the second passages.
THE BACKGROUND OF THE INVENTIONThe plate heat exchanger in such a heat exchanger device may be an evaporator used for production of cold in various applications, such as air-conditioning plants, cooling in food stores, cooling in industrial processes, etc. In typical cases, a heat transfer medium in the form of a liquid, for instance water, is thereby to be cooled from a first temperature to a second. The temperature difference between the temperature of the outgoing heat transfer medium and the temperature of the cooling agent is advantageously relatively small. It is important that the cooling agent in the evaporator, which provides the cooling of the heat transfer medium, is completely evaporated before it leaves the evaporator and is supplied to the compressor. If there are liquid droplets left in the cooling agent, these droplets will damage the compressor and reduce the efficiency and the lifetime of the compressor.
In order to avoid such liquid droplets in the cooling agent, it is known to superheat the cooling agent at the cooling agent outlet of the evaporator. For instance, it is known to provide such a superheating by means of the liquid to be cooled, i.e. the incoming liquid is firstly conveyed passing the outgoing cooling agent in order to raise the temperature of the cooling agent. One problem in this context is to have a sufficient temperature difference between the incoming liquid and the outgoing cooling agent. If this temperature difference is small, large heat transfer surfaces are required, which leads to a large evaporator.
On the other hand it is important the superheating is not going too far. If the cooling agent supplied to the compressor has a high temperature the required compressing work is large, which makes the cooling process energy-requiring.
PRIOR ARTEP-B-497 339 discloses a heat exchanger device having a plate heat exchanger used as evaporator in a cooling agent circuit. The plate heat exchanger includes a first plate part and a second plate part for the evaporation proper. In the first plate part the cooling agent to be supplied to the evaporator is conveyed in heat exchanging contact with the cooling agent leaving the evaporator. The expansion valve of the cooling agent circuit is provided upstream the first part for the incoming cooling agent. A further valve for the incoming cooling agent is provided downstream the first plate part.
U.S. Pat. No. 5,678,419 discloses a similar heat exchanger device having a plate heat exchanger used as evaporator in a cooling agent circuit.
EP-A-1 083 395 discloses a cooling agent circuit including an evaporator, a compressor, a condenser and an expansion valve. The cooling agent leaving the condenser is conveyed in heat-exchanging contact with the cooling agent leaving the evaporator and supplied to the compressor.
DE-A-34 42 169 discloses a similar cooling agent circuit including an evaporator, a compressor, a condenser and an expansion valve. The cooling agent leaving the condenser is conveyed in heat exchanging contact with the cooling agent leaving the evaporator and supplied to the compressor.
SUMMARY OF THE INVENTIONThe object of the present invention is to provide a heat exchanger device with a plate heat exchanger to be used as an improved evaporator in a cooling agent circuit. A further object is to reduce the presence of liquid droplets in the cooling agent leaving the plate heat exchanger. A further object is to provide an evaporator having a high efficiency. The further object is to provide an evaporator having a large capacity in relation to the size of the evaporator. A further object is to provide a heat exchanger device that has a simple construction.
This object is achieved by the heat exchanger device initially defined, which is characterised in that said conduit includes a conduit portion extending into and out of the outlet channel for the cooling agent in such a way that heat exchange takes place between the cooling agent in said conduit portion and the cooling agent in the outlet channel.
The cooling agent is thus conveyed to its inlet channel and into the plate heat exchanger via the inventive conduit portion, which extends into and out of the outlet channel of the cooling agent. Consequently, the invention creates possibilities to raise the temperature of the cooling agent leaving the plate heat exchanger by means of the cooling agent located in the conduit portion. By means of the conduit portion according to the invention it is possible to prevent the cooling agent leaving the plate heat exchanger from containing liquid droplets. The cooling agent in the conduit portion may have a high temperature, for instance if the cooling agent located in the conduit portion arrives directly from a condenser of a cooling agent circuit. The possible liquid droplets which are too large or which have not yet been evaporated in the plate heat exchanger will be finely distributed, evaporated and superheated in contact with the conduit portion. Since the liquid droplets in the cooling agent thus may be minimised both in number and size, and the superheating is controlled, both the lifetime and the efficiency of the compressor are increased.
An evaporator formed by the heat exchanger device according to the invention has a higher capacity and/or efficiency than conventional evaporators. It is possible to achieve a smaller temperature difference between the cooling agent and the out-going heat transfer medium than for conventional evaporators. In addition, the heat exchanger device according to the invention has a simple construction. The heat exchanger device according to the invention may be obtained by afterwards supplementing a plate heat exchanger by the conduit portion as defined.
According to an embodiment of the invention, the outlet channel for the cooling agent includes the fourth porthole channel and a pipe extending outwardly from the fourth porthole channel and the plate package, wherein said conduit portion extends at least into and out of said pipe. Advantageously, said conduit portion may also expand into and out of the fourth porthole channel.
According to a further embodiment of the invention, said conduit portion extends in a U-shaped path in the outlet channel. In order to increase the heat transfer to the cooling agent leaving the plate heat exchanger, said conduit portion may include surface enlarging members provided on the conduit portion and extending in the outlet channel. Such surface enlarging members may include flanges. Furthermore, it is possible to let said conduit portion extend in a path which is significantly longer than the double distance between an entrance position for the entrance of the conduit portion in the outlet channel and a position of the conduit portion located as far as possible away from the entrance position. For instance, said conduit portion may extend in a zigzag-shaped or helical-shaped path in the outlet channel.
According to a further embodiment of the invention, said conduit is included in a cooling agent circuit which includes a compressor, a condenser, and expansion valve and an evaporator that includes the plate heat exchanger. Said conduit portion is located between the condenser and the expansion valve.
According to a further of embodiment of the invention, the inlet and outlet channels are provided in such a way that the heat transfer medium flows through the first passages in a counterflow direction or parallel flow direction in relation to the cooling agent in the second passages.
BRIEF DESCRIPTION OF THE DRAWINGSThe present invention is now to be explained more closely through a description of various embodiments shown by way of example and with reference to the drawings attached hereto.
The heat exchanger plates 12 are arranged in such a way that first passages 18 and second passages 19 are formed between the plates 12. The first passages 18 are intended to convey a heat transfer medium to be cooled and the second passages 19 are intended to convey a cooling agent. The plate package 11 includes a first porthole channel 21 and a second porthole channel 22, a third porthole channel 23 and a fourth porthole channel 24. The first porthole channel 21 and the second porthole channel 22 communicate with the first passages 18. The third porthole channel 23 and the fourth porthole channel 24 communicate with the second passages 19. The first porthole channel 21 forms at least a part of an inlet channel 31 for supplying the heat transfer medium to the plate heat exchanger 10. The second porthole channel 22 forms at least a part of an outlet channel 32 for discharging the heat transfer medium from the plate heat exchanger 10. The third porthole channel 23 forms at least a part of an inlet channel 33 for supplying the cooling agent to the plate heat exchanger 10. The fourth porthole channel 24 forms at least a part of an outlet channel 34 for discharging the cooling agent from the plate heat exchanger 10. In the embodiment disclosed in
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The heat exchanger device also includes a sensor device 41 provided at or in the outlet channel 34 for the cooling agent. The sensor device 41 includes sensors for sensing the temperature and the pressure of the cooling agent discharged from the plate heat exchanger 10. In the embodiment disclosed in
The invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claim.
Claims
1.-11. (canceled)
12. A heat transfer device comprising a plate heat exchanger, wherein the plate heat exchanger includes a plate package of heat transfer plates, which are arranged to form between the plates first passages for a heat transfer medium to be cooled and second passages for a cooling agent, wherein:
- the plate package includes a first porthole channel and a second porthole channel, which communicate with the first passages, and a third porthole channel and a fourth porthole channel, which communicate with the second passages;
- the first porthole channel forms at least a part of an inlet channel to supply the heat transfer medium to the plate heat exchanger;
- the second porthole channel forms at least a part of an outlet channel to discharge the heat transfer medium from the plate heat exchanger;
- the third porthole channel forms at least a part of an inlet channel to supply the cooling agent to the plate heat exchanger;
- the fourth porthole channel forms at least a part of an outlet channel to discharge the cooling agent from the plate heat exchanger;
- the heat exchanger device includes a conduit extending into the inlet channel for the cooling agent to supply the cooling agent to the third porthole channel and the second passages, and
- wherein the conduit includes a conduit portion extending into and out of the outlet channel for the cooling agent such that heat exchange takes place between the cooling agent in the conduit portion and the cooling agent in the outlet channel.
13. A device according to claim 12, wherein the outlet channel for the cooling agent includes the fourth porthole channel and a pipe which extends outwardly from the fourth porthole channel and the plate package, wherein the conduit portion extends at least into and out of the pipe.
14. A device according to claim 13, wherein the conduit portion extends into and out of the fourth porthole channel.
15. A device according to claim 12, wherein the conduit portion extends in a U-shaped path in the outlet channel.
16. A device according to claim 12, wherein the conduit portion includes surface enlarging members, which are provided on the conduit portion and extend in the outlet channel.
17. A device according to claim 16, wherein the surface enlarging members include flanges.
18. A device according to claim 12, wherein the conduit portion extends in a path which is significantly longer than double the distance between an entrance position for the entrance of the conduit portion into the outlet channel and a position of the conduit portion located as far as possible from the entrance position.
19. A device according to claim 12, wherein the conduit portion extends in a zigzag-shaped or helical-shaped path in the outlet channel.
20. A device according to claim 12, wherein the conduit is included in a cooling agent circuit, which includes a compressor, a condenser, an expansion valve and an evaporator that includes the plate heat exchanger.
21. A device according to claim 20, wherein the conduit portion is located between the condenser and the expansion valve.
22. A device according to claim 12, wherein the inlet and outlet channels are arranged such that the heat transfer medium flows through the first passages in a counterflow direction or a parallel flow direction in relation to the cooling agent flow in the second passages.
Type: Application
Filed: Nov 9, 2004
Publication Date: Apr 19, 2007
Inventor: Mats Stromblad (Bastad)
Application Number: 10/579,026
International Classification: F25B 41/00 (20060101); F28D 7/10 (20060101);