US20100181045A1

US20100181045A1 - Heat exchanger

Info

Publication number: US20100181045A1
Application number: US12/667,702
Authority: US
Inventors: Veronika Bognarne Fejes
Original assignee: WTS KERESKEDELMI ES SZOLGALTATO KFT
Current assignee: WTS KERESKEDELMI ES SZOLGALTATO KFT
Priority date: 2007-07-17
Filing date: 2008-06-02
Publication date: 2010-07-22
Also published as: DE102007033166A1; ATE486259T1; PL2165143T3; CN101796364B; ES2355016T3; EP2165143B1; HK1146648A1; WO2009010834A1; EP2165143A1; UA97285C2; DK2165143T3; PT2165143E; ZA201000973B; DE502008001668D1; CN101796364A; SI2165143T1

Abstract

The invention relates to a heat exchanger (10) having an elongate hollow body with connections (12, 12′, 13, 13′) for the supply and discharge of a first and of a second medium, in which the first medium is guided through the elongate hollow body in a counterflow with respect to a second medium, and the second medium flows through a spiral tube (11) which extends longitudinally axially between the end sides of the hollow body, and wherein a plurality of deflecting elements (18) projects into the hollow body interior from the hollow body inner casing, which deflecting elements deflect the flow of the first medium. To improve efficiency, it is provided that the deflecting elements project in an alternating sequence from in each case opposite hollow body sides into the hollow body interior and into the region of the spiral tube, in such a way that said deflecting elements end between two spirals, and that the hollow body inner casing has, in sections, a plurality of concavely-shaped constrictions.

Description

The invention relates to a heat exchanger, particularly for a swimming pool, having an elongated tubular body with connectors for inflow and outflow of a first and a second medium, the first medium being guided through the elongated tubular body in opposite or codirectional flow to the second medium, the second medium flowing through a helicoidal pipe (11) that extends longitudinally axially between ends of the tubular body, multiple deflector vanes that deflect the flow of the first medium projecting into the tubular body interior from the inner surface of the tubular body.
Swimming-pool heat exchangers are used to heat the pool water as a first medium, using a heating medium as a second medium. Usually, for this purpose, heat exchangers are used essentially composed of a large pipe for pool water and a heating coil within it for a heating medium. When the two media flow through their related pipes, the pool water absorbs heat from the heating medium, which consequently becomes cooler. The heating coil can assume many different shapes within the heat exchanger. The effectiveness of usual heat exchangers depends, among other things, on how large the surface of the heating coil is within the heat exchanger. The larger the surface of the heating coil, the more effectively the heat exchanger works. Usually, to increase the surface, the heating coil is formed as a spiral inside the heat exchanger. In the case of heat exchangers of the type described above, the medium to be heated flows through the center of the helicoidal heating coil, or the medium flows around the heating spiral on the outside. The same principle is also used for flow-through heaters in which the heating coil is a coil that can be heated electrically. The difference from a heat exchanger is that in the case of a flow-through heater, significantly more heat is given off to the water flowing through. All of the embodiments of the heat exchanger according to the invention that are named in the specification and in the claims can basically also be transferred to a flow-through heater having the same construction.
A heat exchanger of this type is described, for example, in DE 100 51 756 [US 2002/0074111]. A heating medium is fed into the heat exchanger housing by way of feed lines extending perpendicularly to the heat exchanger housing, and flows through the heating coil. At the same time, pool water is guided longitudinally axially into the heat exchanger, flows around the heating coil in doing so, and consequently absorbs heat. The flow-through directions of the two media through the heat exchanger are selected to be in opposite directions.
U.S. Pat. No. 5,309,987 describes a heat exchanger with baffle plates that extend circles over the inner surface of a cylindrical housing, with the exception of a few openings, and are supposed to ensure that a turbulent flow of the medium flowing through is generated. Because of the placement of the baffle plates relative to the longitudinal axis of the housing at a slant, there is the danger that because of turbulence that occurs, congestion zones occur in individual regions from which the first medium used will flow away only insufficiently so that only insufficient heat transfer will also take place.
U.S. Pat. No. 1,893,484 describes a heat exchanger that has a cylindrical housing, on the inner surface of which guide blades lying on a spiral are provided. Because of this spiral-shaped arrangement of the guide blades, a clearly greater laminar flow is produced, in contrast to the center region of the housing interior in which the helicoidal pipe is disposed, so that there is the danger that the first medium will accumulate in the region of the helicoidal pipe and will not flow away.
It is the object of the present invention to improve known heat exchangers in such a manner that their energy efficiency is optimized, while the design of the heat exchanger is nevertheless compact and space-saving.
This object is attained by the heat exchanger according to claim 1, which is characterized in that the deflector vanes project all the way into the region of the helicoidal pipe in an alternating sequence from opposite sides of the tubular body in such a manner that they end between two turns and that the inner surface of the tubular body has a plurality of separate concave constrictions.
Further developments of the invention are described in the dependent claims.
The heat exchanger according to the invention is particularly provided for heating swimming pools, but other liquids can be heated as well. For example, the heat exchanger can be used to heat aquarium water. The heat exchanger according to the invention is basically also suitable for use as a cooler.
The effect of the heat exchanger according to the invention particularly consists in that the deflector vanes that are provided guide the water to be heated toward the helicoidal pipe in a targeted manner. Furthermore, the flow velocity of the first medium (used water) is controlled in such a manner that a longer dwell time along the helicoidal pipe coil and thus a greater heat transfer are achieved.
The inflowing first medium is guided between the helicoidal turns by the deflector vane in a targeted manner so that flow acceleration is produced in the narrow regions of the elongated tubular body, and pressure relief and therefore lower flow speeds are produced in the wider regions of the tubular body interior that lie between the narrow regions.
According to a particular embodiment of the invention, the elongated tubular body is oval or elliptical, the deflector vanes being preferably mounted on the narrow sides of the oval. This measure also optimizes both the dwell time of the first medium in the region of the helicoidal pipe coil and the stability of the heat exchanger housing.
Furthermore preferably, two to three 360° turns of the helicoidal pipe are between two adjacent deflector vanes. It has been shown that this optimization creates the greatest possible heat transfer between the helicoidal pipe and the first medium. The configuration of the helicoidal pipe as a corrugated pipe, which has a greater surface as compared with a smooth-wall pipe, serves the same purpose.
The inner surface of the tubular body has a smooth surface, thereby avoiding deposits and undesirable turbulence of the first medium that flows past there.
Furthermore to optimize the flow stream of the first medium, the deflector vanes are flat bodies having an inner edge that is preferably curved in concave manner.
Both for production technology reasons and in order to prevent undesirable heat emission of the housing to the outside surroundings, the elongated tubular body, preferably including the deflector vanes, is made from plastic, particularly polyamide. The plastic housing can particularly be produced by injection molding.
In the case of another embodiment of the invention, the elongated tubular body consists of multiple pieces that can be inserted into one another and are releasably connected with one another. In this manner, a heat exchanger having a modular structure is created that consists of any desired number of individual pieces made from heat-resistant and, above all, corrosion-resistant plastic, having a great insulation effect and great reliability to prevent calcification.
To fasten the elongated tubular body to a wall, its housing has tabs that project from its outer surface, with a hole to allow a mounting screw to pass through.
Furthermore preferably, a bracket is provided for fastening the elongated tubular body to a wall, the ends of which bracket are bent by 180° and have as seen in top view aligned bores to allow a bolt shaft or screw shaft to pass through.
The 180° bend of the bracket ends creates the possibility of tightening the bolt or the screw in such a manner that a pressure stress is built up in the U-shaped, bent part, by means of which loosening of the screw connection is avoided right from the start.
According to another embodiment of the invention, the bracket has a concave center section that preferably has the same curvature as the elongated tubular body that lies against it.
According to another embodiment, the deflector vanes are individual wall pieces that project into the housing interior either perpendicularly or inclined by 2° to 3° relative to the perpendicular. In the case of an incline relative to the perpendicular, the angle between the flow direction of the first medium and the deflector vanes therefore amounts to approximately 88°.
Furthermore, the deflector vanes project into the tubular body interior in an alternating sequence from opposite sides of the tubular body interior by an edge dimension of ⅓ to 1/7, preferably ⅕ of the inside diameter of the tubular body.
The inner surface of the tubular body is at least partly wave-shaped toward the longitudinal axis, constrictions of the diameter preferably amounting to 5% to 10% of the tubular body interior. The connectors for the first and second medium are mounted on the ends in a preferred embodiment.
The heat exchanger consists of multiple individual elements, making it possible to select the length of the heat exchanger as desired, since as many elements as desired can be connected with one another. Each of the elements has a mounting tab, so that even larger heat exchangers can be securely fixed in place. Fastening of the heat exchanger can be fixed together on an existing masonry construction, i.e. a wall, or suspended from a ceiling, or for fastening on a pallet for integration within a system. If one uses the heat exchanger to heat swimming pool water, then heating can take place both by heating water and by solar heat. The heating medium, as a second medium, is guided through a helicoidal pipe shaped like a rib. This helicoidal pipe serves as a heating water pipe against which the first medium flows both vertically and horizontally in the heat exchanger, so that uniform heat removal is possible. The convex-concave construction of the heat exchanger housing with internal deflector vanes lengthens the dwell time of the first medium in the heat exchanger housing, thereby guaranteeing a strong heat transfer. The heating medium can be cooled more strongly, thereby resulting in a lower heat loss on the return segment and thus a saving in heating energy. The helicoidal heating water rib pipes are preferably made from highly corrosion-resistant and pressure-resistant stainless steel, and screwed in on the end with a double nipple.
The deflector vanes that are preferably selected project into the tubular body interior by 20 mm to 30 mm, preferably a by 25 mm, specifically at an angle of 90° or slightly inclined relative to the inflow direction, by 2° or 3°. The deflector vanes are circle segments and have a concave inner edge, but this edge can also be shaped differently. The medium to be heated is guided past the heating coil provided in the center of the helicoidal pipe several times by the deflector vanes fixed alternately on opposite sides of the heat exchanger interior. Because of this special construction of the deflector vanes, the flow direction of the first medium to be heated is constantly changed, so that it is guided past the helicoidal heating coil in an improved manner in counter-flow. The successive constrictions and expansions in the housing interior furthermore bring about alternating compression and relaxation of the flowing first medium, with the result that the dwell time of the first medium in the region of the heating coil is increased, and thus the heat transfer is improved.
The oval shape of the heat exchanger allows great internal stresses without material stresses being formed. The deflector vanes, which are integrated into the narrow sides, furthermore improve the statics of the heat exchanger housing.

Further embodiments of the invention will be described in the following, using the drawings. Therein:

FIG. 1 a is a longitudinal axial section through the heat exchanger with an integrated helicoidal heating coil,

FIG. 1 b is a cross section through the heat exchanger,

FIG. 1 c is a longitudinal axial section through the heat exchanger with a possible flow path,

FIG. 1 d is a longitudinal axial section through the heat exchanger with another possible flow path,

FIG. 2 a shows a heat exchanger without a center part,

FIG. 2 b shows a heat exchanger with one center part,

FIG. 2 c shows a heat exchanger with two center parts,

FIG. 3 is a lateral axial section a mount in an exploded view,

FIG. 4 is a longitudinal axial section through a flow-through heater,

FIG. 5 is a cross section through a heat exchanger.

FIG. 1 a shows a heat exchanger 10 with an integrated helicoidal pipe 11 as a heating coil. Here, hot water passing through the helicoidal pipe is the heating medium. Alternatively, however, it is also possible to make the helicoidal pipe a heating coil heated with electrical current (like an immersion heater). The helicoidal pipe 11 can have a smooth outer surface, but preferably is corrugated. The helicoidal pipe 11 is mounted on fittings 13 and 13′ at the ends of the heat exchanger housing.
Water connectors 12 and 12′ each formed by a flange adapter and union nut are preferably made from ABS and serve as intake and outlet for the first medium that is to be heated. Preferably, the first and second medium flow countercurrent to each other. The heat exchanger 10 has a housing of oval cross-section. The flow direction of the first medium is indicated by arrow 14 and the flow direction of the second medium by arrow 15. Here, the heat exchanger has two end caps 16 and 16′ and two center parts 17 and 17′ that fit into each other and with the end caps to form the heat exchanger 10. The end caps and the center parts 16, 16′, 17, 17′ engage into one another with adjacent parts fixed in place by a connection that consists of nuts and bolts. To this end, the end caps and intermediate pieces 16 and 16′ have outside tabs with bores through each which a bolt or a screw shaft can be inserted.
Basically the number of center parts 17, 17′ can be freely selected.
On their inner surfaces the center parts 17 and 17′ have deflector vanes 18 that project perpendicularly into the tubular body interior. Alternatively, in place of the perpendicular orientation, an orientation tilted slightly, namely by 2° to 3° against the flow direction 14, can also be used. The deflector vanes 18 are provided where the inside diameter narrows, viewed in the inflow direction 14.
Viewed in the flow direction, a second deflector vane 18 lies on the opposite inner end surface of the tubular body, at an axial spacing. The deflector vanes project so far into the heat exchanger housing that they end in the region of the helicoidal pipe 11. Two to three turns of the helicoidal pipe 11 lie between two adjacent deflector vanes on opposite sides.
Rims 101 of the end caps and center parts that bear axially on one another are sealed by an 0-ring 102 fitted in a groove.
FIG. 1 b shows a detail indicating that the heat exchanger 10 has an oval cross-sectional shape. Connections 103 that consist of a screw and nut can be seen on the edge of the housing.
FIGS. 1 c and 1 d show flow lines 104 and 106 that can be modified by using different pressures and flow velocities of the inflowing first medium. In each case, it can be seen that the incoming first medium, particularly swimming pool water, impinges the deflector vanes 18 and is guided from there toward the helicoidal pips, but the flow experiences a reversal in direction and is passed back in a loop-shaped movement where it meets water newly flowing in. Depending on the pressure that is set, the deflections or turbulence that are indicated with 105 in FIG. 1 c are configured to be greater or smaller. The essential thing is that with a longer dwell time the first medium to be heated, particularly swimming pool water, flows through the heating coil, i.e. the helicoidal pipe 11, not only once but rather several times.
FIGS. 2 a to 2 c show heat exchangers 20, 20′, and 20″ according to the invention in different lengths produced in that two end caps are connected with one another directly or by way of one or two or more center parts. Depending on the number of center parts inserted between two end caps, the length of the heat exchanger can be varied as desired and adapted to the desired conditions.
FIG. 3 shows in an exploded view how the heat exchanger is fastened to a wall 32. For this purpose, the heat exchanger 30 has tabs 301 that project from its outer surface and that each have a hole, such as a bore or slot, for example, to allow a mounting screw 31 to pass through. In order to prevent the heat exchanger from gradually coming loose from its mount due to vibrations during heat exchanger operation, a bracket 32 [39] is provided bent back 180° at its ends 33 and 34. The bracket 32 [39] consists of a thin-walled metal sheet that has two bores that are congruent at the 180° bends and through which the shaft of the screw 31 can pass. This screw furthermore engages into screw anchors 35 that are anchored in the wall 32.
When the screw 31 is tightened, a pressure is exerted on the U-profile of the bracket at its ends 33 and 34, which pressure permanently acts on the screw head after the screw 31 has been fixed in place, thereby preventing it from rotating. In addition, a lock nut 36 and a washer 37 (each with a screwthread formation) can be used as further devices to prevent rotation.
The bracket 32 has a concave center section 38 whose shape is complementary to the outer surface, i.e. the radius of curvature, of the heat exchanger.
The system is oriented in such a manner that both media that provide heat and electrical heating coils can be used, which can also be operated with solar heat. FIG. 4 shows a flow-through heater 41 that has heating coils 42 that can be electrically heated and are to the left housing part. The embodiment shown comprises merely one center element in which two deflector vanes are provided. Because of the electrical connection mounted on the end, the water connection 44 is provided not on the end but on the side of the flow-through heater 41. Furthermore, a possible circular flow path 45 of the water to be heated is shown. Of course, a wave-shaped flow path is also possible, such as that shown in FIG. 1 c, for example.
FIG. 5 shows an embodiment of the deflector vanes 18 that are shown with cross-hatching. The deflector vanes form a segment that extends out of the wall of the heat exchanger toward the interior. From the deepest point, the height of the deflector vane with reference to the greatest diameter of the heat exchanger (which is vertical here) amounts to between ⅕ and ¼. The upper edge of the deflector vane is concave.

Claims

1. A heat exchanger, particularly for a swimming pool, the heat exchanger comprising:

an elongated tubular body with connectors for inflow and outflow of a first and a second medium, the first medium being guided through the elongated tubular body in opposite or codirectional flow to the second medium,

a helicoidal pipe through which flows the second medium and that extends longitudinally axially between ends of the tubular body, and

multiple deflector vanes that deflect the flow of the first medium projecting into the tubular body interior from the inner surface of the tubular body, the deflector vanes projecting all the way into the region of the helicoidal pipe in an alternating sequence from opposite sides of the tubular body in such a manner that they end between two turns and that the inner surface of the tubular body has a plurality of separate concave constrictions.

2. The heat exchanger according to claim 1, wherein the elongated tubular body is oval or elliptical in cross-section, the deflector vanes being preferably mounted on the narrow sides of the oval.

3. The heat exchanger according to claim 1 wherein two to three 360° turns lie between two adjacent deflector vanes.

4. The heat exchanger according to claim 1 wherein the helicoidal pipe is corrugated.

5. The heat exchanger according to claim 1 wherein the inner surface of the tubular body has a smooth surface.

6. The heat exchanger according to claim 1 wherein the deflector vanes are flat and preferably have a concave arcuate inner edge.

7. The heat exchanger according to claim 1 wherein the elongated tubular body, preferably including the deflector vanes, is made of polyamide.

8. The heat exchanger according to claim 7, wherein the elongated tubular body consists of multiple pipe pieces that can be inserted into one another and are releasably connected with one another.

9. The heat exchanger according to claim 1 wherein the elongated tubular body has projecting tabs on its outer surface and each formed with a hole through which can pass a respective mounting screw.

10. The heat exchanger according to claim 9, wherein in order to fasten the elongated tubular body to a wall, a bracket is provided having ends bent back through 180° and having bores aligned in top view, to allow a bolt or screw shaft to pass through.

11. The heat exchanger according to claim 10, wherein the bracket has a concave center section that preferably has the same radius of curvature as the elongated tubular body.

12. The heat exchanger according to claim 1 wherein the deflector vanes are made from individual wall pieces that project into the tubular body interior perpendicularly or inclined by 2° to 3° from the perpendicular.

13. The heat exchanger according to claim 12, wherein the deflector vanes project into the tubular body interior in an alternating sequence from opposite sides preferably by an edge dimension of ⅓ to 1/7 of the inside diameter of the tubular body.

14. The heat exchanger according to claim 1 wherein the inner surface of the tubular body is at least partially wave-shaped toward the longitudinal axis, constrictions of the diameter preferably amounting to 5% to 10% of the housing interior.

15. The heat exchanger according to claim 1 wherein the connectors for the first and the second medium are disposed on the ends.

16. The heat exchanger according to claim 1 wherein the helicoidal pipe is a heating coil that can be electrically heated.

17. The heat exchanger according to claim 1 wherein the heat exchanger is a flow-through heater.