Heat exchanger with improved flow

Abstract

A heat exchanger comprises a number of identical heat exchanger plates stacked in a stack. Every other heat exchanger plate is turned 180 degrees in its plane relative to its neighboring plates, and each heat exchanger plate comprises at least four port openings and a herringbone pattern comprising pressed ridges and grooves. The ridges and grooves are adapted to keep the plates on a distance from one another under formation of flow channels, wherein areas around the port openings are arranged on different levels, such that selective flow from the port openings to the flow channels is achieved. Dents are arranged in the ridges and grooves in the vicinity of any of the port openings, the dents being arranged to increase the flow resistance to promote a more even flow distribution in the flow channel.

Claims

1. A heat exchanger comprising: (a) a number of identical heat exchanger plates stacked in a stack, wherein every other heat exchanger plate is turned 180 degrees in its plane relative to neighboring heat exchanger plates, and wherein each heat exchanger plate comprises at least four port openings and a herringbone pattern comprising pressed ridges and grooves; (b) said ridges and grooves of the herringbone pattern providing contact points between neighboring heat exchanger plates and keeping the heat exchanger plates a distance from one another and providing flow channels, wherein said flow channels comprise a first flow channel and a second flow channel, wherein areas around the port openings are arranged on different levels, such that selective flow from the port openings to the flow channels is achieved; (c) said port openings comprising a first inlet port opening open to said first flow channel and closed to said second flow channel, and a second inlet port opening closed to said first flow channel and open to said second flow channel; and (d) wherein, seen from a frontal side of the heat exchanger plates, dents are arranged in the grooves of the herringbone pattern of the heat exchanger plates immediately adjacent said first inlet port opening, and dents are not arranged in the grooves of the herringbone pattern of the heat exchanger plates immediately adjacent said second inlet port opening, said dents in the grooves of the herringbone pattern being arranged to increase a flow resistance for fluid traveling in said first flow channel such that the fluid is directed toward a side of the heat exchanger plate where the second inlet port opening is placed to thereby promote a more even flow distribution in said flow channels, wherein said dents in the grooves of the herringbone pattern are placed such that said dents in the grooves of the herringbone pattern do not form contact points with the neighboring heat exchanger plates.

2. The heat exchanger of claim 1, wherein the dents are provided around two neighboring port openings, and wherein the dents in the areas of one of said neighboring port openings are placed in the ridges, and the dents in the areas of the other of the two neighboring port openings are placed in the grooves.

3. The heat exchanger of claim 1, wherein the heat exchanger plates in the stack are joined by brazing.

4. A heat exchanger comprising: (a) a number of identical heat exchanger plates stacked in a stack, wherein every other heat exchanger plate is turned 180 degrees in its plane relative to neighboring heat exchanger plates, and wherein each heat exchanger plate comprises at least four port openings and a herringbone pattern comprising pressed ridges and grooves; (b) said ridges and grooves of the herringbone pattern providing contact points between neighboring heat exchanger plates and keeping the heat exchanger plates a distance from one another and providing flow channels, wherein the said flow channels comprise a first flow channel and a second flow channel, wherein areas around the port openings are arranged on different levels, such that selective flow from the port openings to the flow channels is achieved; (c) said port openings comprising a first inlet port opening open to said first flow channel and closed to said second flow channel, and a second inlet port opening closed to said first flow channel and open to said second flow channel; and (d) wherein, seen from a frontal side of the heat exchanger plates, dents are arranged in the ridges of the herringbone pattern of the heat exchanger plates immediately adjacent said second inlet port opening, and dents are not arranged in the ridges of the herringbone pattern of the heat exchanger plates immediately adjacent said first inlet port opening, said dents in the ridges of the herringbone pattern being arranged to decrease a flow resistance for fluid traveling in said second flow channels to thereby promote a more even flow distribution in said flow channels, wherein said dents in the ridges of the herringbone pattern in the heat exchanger plates are placed such that said dents in the ridges of the herringbone pattern do not form contact points with the neighboring heat exchanger plates.

Description

BRIEF DESCRIPTION IF THE DRAWINGS

(1) Hereinafter, the invention will be described with reference to the appended drawings, wherein:

(2) FIG. 1 is an exploded perspective view of a heat exchanger comprising six identical heat exchanger plates;

(3) FIG. 2 is a perspective view showing one of the heat exchanger plates in FIG. 1; and

(4) FIG. 3 is a perspective view showing the area denoted B in FIG. 2;

DESCRIPTION OF EMBODIMENTS

(5) With reference to FIG. 1, a heat exchanger 100 according to the present invention comprises a number of identical heat exchanger plates 110, each comprising four port openings 130, 140, 150 and 160, the openings 130, 150 being inlet openings and outlet openings, respectively, for a first fluid, the openings 160, 140 being inlet openings and outlet openings, respectively, for a second fluid intended to exchange heat with the first fluid.

(6) The plates also comprise ridges R and grooves G arranged in a herringbone pattern and adapted to keep the plates on a distance from one another under formation of flow channels. Areas around the port openings are arranged on different heights in order to allow for selective fluid flow to the flow channels. The areas around the port openings 130 and 150 are provided on the same height, e.g. the height of the ridges R, whereas the areas around the port openings 140, 150 are provided on another height, e.g. the height of the grooves G.

(7) Two neighboring plates are always mutually turned by 180 degrees in the plane, i.e. such that port openings 130 and 160 will neighbor one another, and port openings 150 and 140 will neighbor one another. As mentioned earlier, the areas surrounding the ports are arranged on different heights, meaning that one pair of port openings placed on one side of the axis of the plates will allow fluid flow into the flow channels arranged by the neighboring plates, whereas the other pair of port openings will be closed, i.e. not allow fluid flow into the same channel. However, the same pair of port openings will be in fluid communication with the flow channels arranged by the next neighboring heat exchanger plate.

(8) Moreover, the heat exchanger plates are provided with a skirt 190 extending around the periphery of the plates 110. The skirts of neighboring plates are arranged to seal the flow channels, such that no leakage to and from the flow channels is allowed.

(9) Finally, end plates 170, 180 are arranged on the outside of the stack of heat exchanger plates. The purpose of the end plates is to increase the strength, i.e. pressure capability of the heat exchanger. Should the pressure requirements be low, the end plates could be omitted.

(10) FIG. 2 shows one of the heat exchanger plates 110; in this figure, some irregularities of the herringbone pattern comprising the ridges and grooves R and G, respectively, are shown in the vicinity of the port openings 130 and 140. In FIG. 3, this area (denoted by B in FIG. 2), is shown in greater detail. In the vicinity of the port openings 150 and 160, the herringbone pattern is not irregular.

(11) As can be seen in FIG. 3, the herringbone pattern comprising ridges R and grooves G is interrupted by dents D; in the vicinity of the port opening 130, the dents D are arranged in the grooves G, whereas in the vicinity of the port opening 140, the dents D are placed in the ridges R.

(12) As mentioned above, the heat exchanger plates are stacked onto one another, wherein each other plate is turned 180 degrees relative to its neighboring plates. If one imagines a plate 110 being placed on top of the plate partly shown in FIG. 3, and turned 180 as compared to this plate, it is clear that the port opening 130 will be open to the flow channel delimited by these two plates, whereas the port opening 140 will be closed.

(13) The dents D in the grooves G in the vicinity of the port 130 will decrease the flow volume, and hence increase the pressure drop, in the vicinity of the port opening 130, whereas the dents D in the ridges R in the vicinity of the port opening 140 will increase the flow volume, and hence decrease the pressure drop for a fluid travelling the flow channel. Considering the port opening 130 is an inlet opening, the fluid will hence be directed towards the side of the axis of the heat exchanger plate where the port opening 140 is placed.

(14) If an identical plate is placed below the plate shown in FIG. 3, the port opening 140 will be open for fluid low into the flow channel delimited by these two plates, and the flow will be directed (or rather urged) to a path on the side of the axis of the heat exchanger plate where the port opening 130 is placed. It is, however, rather unlikely that anyone would place two inlet ports next to one another.

(15) However, due to the identical plates, the impact on the pressure drops, and hence flow distribution will be equal for the port openings 150, 160.

(16) Above, the invention has been described with reference to one single embodiment, which results in a significant improvement in the flow distribution of a plate heat exchanger made from a stack of identical heat exchanger plates, wherein every other plate is turned 180 degrees in the plane as compared to its neighboring plates. In the shown embodiment, this is achieved by providing both the ridges and the grooves of the herringbone pattern holding the plates on a distance from one another by contacting point with dents D. It is, however, possible to achieve the same result by only providing e.g. the grooves G in the vicinity of the port opening 130 with dents, or only the ridges R in the vicinity of the port opening 140 with dents D.

(17) It is also possible to provide the grooves G in the vicinity of both port openings 130 and 150 with dents and the ridges R in the vicinity of both port openings 140, 160 with dents.

(18) The invention could be used both for brazed heat exchangers and for packed heat exchangers, i.e. heat exchangers where the sealing around edge portions and port openings is provided by gaskets.