SE8702608A0 - Flat heat exchangers, such as a vaporizer - Google Patents

Abstract

A plate heat exchanger, for example an evaporator, has parallel, corrugated and bundled plates (2, 2 ') for forming channels (7) therebetween. Each channel has an inlet and an outlet and each other channel is flowed through by a medium intended for evaporation, eg freon, and every other channel (8) is flowed through by a heat-emitting medium in the heat exchanger, eg water. Each plate is provided with hl (9) at the inlets and outlets. Providing an even distribution of the evaporation medium in the plate package, a throttle is provided at each inlet to the channels (7) into which the evaporation medium flows. According to one embodiment, the throttling is constituted by a ring (10), which is placed with good sealing at the inlet of each displacement channel (7), between two evaporating channel-forming plates (2, 2 '), and which has one or more radial, continuous halves or bores (11), which are directed towards the center of the evaporation channel (7). Publication figure = Fig 2.

Description

2 starts earlier in one of these channels, the volume of the evaporation medium suddenly and sharply increases in this channel. Usually the pre-start starts earlier in the narrowest inlet connection covered channels. Since the pressure drop across each channel is equal, the mass flow in said channel decreases while it increases in 8 other channels. In the channel with early evaporation, complete evaporation and even overheating of the evaporated medium thus takes place, while the evaporation in 8 other channels becomes incomplete. Dry, superheated gas flows out of the evaporation ducts, which is mixed with moist, incompletely evaporated gas. Due to the evaporation starting at different times and at different positions in the plate package, the aspirator does not receive the desired dry and highly overheated freon gas, but instead a moist gas.

The 18dda heat exchanger thus has a number of disadvantages when it is used as a precursor. If too much moist gas is obtained from the evaporator, there is a risk that other components in the system, such as the compressor, will be damaged. Furthermore, the moist or incompletely evaporated gas can give rise to pulsations throughout the system, which thereby becomes difficult to regulate. The control devices of the system aim to maintain as smooth a flow as possible through the system, which is, however, aggravated by said pulsations. At low evaporation temperatures for friends, let alone around 0 ° C or daily, the other medium, usually flowing through the evaporator, usually water, can freeze, after which there is a risk that the entire heat exchanger will freeze. A further phenomenon with a negative impact is that the outgoing temperature and possibly also the overheating temperature of the evaporated medium are constantly changing, which gives rise to serious operational disturbances and control problems.

An object of the present invention is to provide a plate heat exchanger, for example a evaporator, in which the inflowing evaporator medium is distributed as evenly as possible throughout the plate package while eliminating the above-mentioned gas completely and evaporating. . Another object is that the above-mentioned antiquities should be eliminated by simple modifications of a standard plate heat exchanger using a fatal additional component.

These and other objects, which will appear from the following description, have now been achieved in that the initially mentioned plate heat exchanger according to the invention can be characterized in that a throttle is arranged at each inlet to the channels in which the packaging medium flows to provide an even distribution of the precursor medium in the plate package.

Preferred embodiments of the invention are set out in the following dependent claims.

The invention will be described in more detail in the following section with reference to the accompanying drawings, which show various embodiments of the invention.

Fig. 1 shows in perspective and with some parts cut off a solder plate heat exchanger of standard type.

Fig. 2 shows in perspective a first embodiment of the invention with two evaporation channel-forming plates in particular.

Fig. 3 shows the same embodiment in a different perspective with the plates joined together.

Fig. 4 shows in a view similar to Fig. 2 a second embodiment of the invention.

Fig. 5 shows in a view similar to Fig. 3 a third embodiment of the invention.

Fig. 1 shows a solder plate heat exchanger, generally denoted by 1, which can, for example, be used as an evaporator in a heat pump system. The heat exchanger 1 comprises a large number of parallel plates, which are soldered together into a package. The plates 2 are edge corrugated according to a herringbone monster, which partly promotes turbulence formation, partly provides contact points or charging points for the plates. The plates 2 are similar but are alternately 4 used to form the channels described in more detail below. The evaporation medium, such as freon, is supplied via a lower inlet connection 3 and removed via an upper outlet connection 4, while the medium in the heat exchanger, for example having water, is supplied via an upper inlet connection 5 and removed via a lower outlet connection. Every other channel 7, here marked with light color, is flooded by friends while every other channel 8, marked with dark color 10, is flooded by water.

The incoming freon is a gas / liquid mixture, which reaches a temperature of about 0 ° C and stands under a pressure of about 0.5 MPa. The water reaches a temperature of about ° C.

According to the invention, a throttle is provided at each inlet to the channels in which the flange medium or vein flows. This throttling can be achieved in many different ways and in the following three different solutions are reported.

Fig. 2 shows a first embodiment, in which such a choke is achieved. Two plates 2, 2 ', which are shown in the ice and between which an evaporation channel 7 for freon (see Fig. 1) is formed, have at the corners placed, opposite each other hall 9 and 9', respectively. (PA correspondingly has the plates slippery for the flowing water). The freon flows through the opening 9 in the direction of an arrow A and then up between the plates 2, 2 'in the narrowing channel 7 in a direction marked by a thick arrow. The throttle is provided by means of a ring 10 placed between the plates 2, 2 ', which has one or more radial, through holes or bores 11, which are preferably directed towards the center of the evaporation channel 7. (Only one bore 11 is shown in Fig. 2). It is understood that the ring 10, when the plate package is pulled together, abuts with good sealing against the plates 2, 2 'around the tail 9 and 9', respectively. In fact, it is loaded against the tiles.

Thanks to the ring 10, a very initial pressure drop is achieved at the inlet to the pre-release channel 7, while the pressure drop into the plate package is relatively small. This meant that the friend is divided evenly in the package and that it rises evenly in the pre-emptive channels 7 via the bores 11 accommodated in the rings 10. the pressure drop at the throttle, ie the ring 10, dr dominant. The throttle in the bores 11 is thus very large in relation to the pressure drop which an early evaporation of the friend can entail.

Fig. 3 shows the plates damaged in Fig. 2 brought together and in a different perspective, showing the location of the ring 10 between them and the bore 11. Note that the bore 11 is directed towards the center of the evaporation channel while in Fig. 2 the clearing shell is directed straight. uppat.

A second embodiment of the invention is shown in Fig. 4, in which the throttling in the stable is effected by means of a tube 12 extending through the tail 9, 9 ', the mantle surface of which is provided with one or more radial, continuous bores 13, corresponding to the ring 10 bores 11. The bores 13 air accommodated in the tube 12 are arranged at intervals corresponding to the distance between the evaporation channels 7 of the plate package, in which the veins flow upwards. Preferably, the 16ds tube 12 is in place at the same time as the soldering of the entire plate package while ensuring good sealing. One skilled in the art will appreciate that the bores 13 may be replaced by a slot (not shown) extending along the entire tube 12, thereby obtaining a corresponding effect.

Fig. 5 shows a third embodiment of the invention, where the throttling is effected by the plates 2, 2 'being pressed against each other at the edge of the openings 9 and 9', respectively. This meant that the plates 2, 2 'abut against each other along a significant part of the inlet 6 to the ford channel 7 with the exception of a stable, where an opening 14 is left. This opening 14 corresponds to the bore 11 of the previously described ring 10 (see Fig. 3) and is preferably directed radially towards the center of the displacement channel 7. In this embodiment it is of course of utmost importance that the abutment of the plates 2, 2 'at Mien 9, 9' is really taken. It should be understood that the opening 14 could be replaced by a very narrow gap extending along a larger part of the inlet to the displacement channel 7.

Common to the three embodiments described here is that the total area of the radial bores 11 and 13, respectively, or the radial openings 14 is substantially smaller than the total inlet area to the evaporation channels 7 in order to obtain a sufficient throttle. Practical experiments have shown that the ratio between said total area and said total area is about 0.005-0.10 and preferably about 0.01-0.02, depending on which media are used and of course which pressures and temperature differences are relevant.

Claims (7)

PATENT REQUIREMENTS A plate heat exchanger, for example an evaporator, which has parallel, corrugated and bundled plates (2, 2 ') for forming channels (7, 8) between adjacent plates, each duct (7, 8) has an inlet and an outlet and wherein every other channel is flowed through by a medium intended for lining and every other channel (8) is flowed through by a medium which gives heat in the heat exchanger and wherein each plate (2, 2 ') is provided with h81 (9) at the inlets and outlets, can be shown as a throttle, that a throttle is arranged at each inlet to the channels (7) in which the trapping medium flows to achieve an even distribution of the displacing medium in the plate package. Heat exchanger according to claim 1, characterized in that the throttle 8 is provided by means of an annular member (10), which is arranged with good sealing at the inlet of each liner channel (7) and which has one or more radial, through-holes or bores (11). ; 13), which dr directed towards the evaporation channel (7). Heat exchanger according to claim 2, characterized in that the annular member consists of a ring (10) ring (10) formed between two pre-channel channels (2, 2 '). Heat exchanger according to claim 2, wherein the inlet hall 25 (9, 9 ') 1 plate package Or is concentric, characterized in that the annular member is constituted by a tube (12) extending through the inlet hole (9, 9'), the mantle surface Or provided with the aforementioned bores (13), which Or arranged at intervals corresponding to the distance between the vanishing channels (7). Heat exchanger according to claim 1, characterized in that the plates (2, 2 ') abut against each other along a significant part of the inlet to each evaporation channel (7) to form a radial inward 8 towards the evaporation channel (7) directed and named throttling effecting Opening (14). Heat exchanger according to any one of claims 2-5, characterized in that the total area of the radial bores (11; 13) or the radial openings (14) is substantially smaller than the total inlet area of the clearance channels (7). Heat exchanger according to claim 6, characterized in that the ratio between said total area and said total area is about 0.005-0.10, preferably about 0.01-0.02.