EP1252470B1

EP1252470B1 - Heater and/or cooler

Info

Publication number: EP1252470B1
Application number: EP01902931A
Authority: EP
Inventors: Pontus BÜLOW NIELSEN; Ralf Blomgren; Martin Holm; Mats Nilsson
Original assignee: Alfa Laval Corporate AB
Current assignee: Alfa Laval Corporate AB
Priority date: 2000-02-01
Filing date: 2001-01-30
Publication date: 2005-03-16
Anticipated expiration: 2021-01-30
Also published as: SE0000336D0; EP1252470A1; SE0000336L; SE518190C2; DE60109418D1; WO2001057452A1; ATE291204T1; AU2001230694A1

Abstract

The present invention concerns a heater and/or cooler comprising at least one tank (2) with at least one inner space (3) and at least one plate heat exchanger (4a, 4b) for at least two heat exchanging fluids, which heat exchanger (4a, 4b) is permanently joined and comprises at least one core of plates with a plurality of heat exchanging plates (5a, 5b) and at least two end plates (6a, 6b, 7a, 7b), the heat exchanging plates (5a, 5b) creating plate interspaces between each other. Each one of the heat exchanging plates (5a, 5b) is provided with one or several corrugations and at least two port holes being parts of at least one inlet channel (10a, 10b) and at least one outlet channel (11a, 11b), respectively, through the core of plates for at least one of the fluids, a first inlet channel (10a, 10b) and a first outlet channel (11a, 11b) being intended for a first fluid and being in fluid communication with a first set of plate interspaces. The said at least one plat heat exchanger (4a, 4b) is housed in the said at least one tank (2), a second set of plate interspaces being in fluid communication with the said at least one inner space (3) in the said at least one tank (2).

Description

The present invention concerns a heater and/or cooler comprising at least one tank with at least one inner space and at least two plate heat exchangers for at least two heat exchanging fluids, each of the plate heat exchangers being permanently joined and comprising at least one core of plates with a plurality of heat exchanging plates and at least two end plates, and plate interspaces being formed between the heat exchanging plates.

EP, A2 0 905 453 discloses a water heater which in addition to a primary heat exchanger heated by a heat source also comprises a secondary heat exchanger and a hot water storage. The hot water storage is in close thermal contact with heat exchanging plates in the secondary heat exchanger and is built together with it. The described modes of execution of the hot water storage is, however, not at optimum concerning heat transfer, strength, material consumption etc.

In accordance with the present invention there is provided a heater and/or cooler comprising at least one tank with at least one inner space and at least two plate heat exchangers for at least two heat exchanging fluids, each of the plate heat exchangers being permanently joined and comprising at least one core of plates with a plurality of heat exchanging plates and at least two end plates, first and second sets of plate interspaces being formed between the heat exchanging plates of each heat exchanger wherein
each heat exchanging plate having one or more corrugations extending between spaced apart, parallel first and second planes, which planes are substantially parallel with all the heat exchanging plates as well as the end plates,
each heat exchanging plate having at least two port holes for forming through the core of plates at least one inlet channel and at least one outlet channel for at least the end plates having port holes respectively communicating with the said at least one inlet channel and the said at least one outlet channel, and
the said at least two plate heat exchangers being housed in the said at least one tank, with the second set of plate interspaces being in fluid communication with the said at least one inner space in the said at least one tank,
the said at least one tank containing a second fluid,
wherein
at least one partition wall divides the said at least one inner space into part spaces that are in fluid communication with each other at an upper part of the tank, whereby fluid may pass freely between said part spaces at the upper part of the tank,
each of the part spaces accommodates at least one of the plate heat exchangers,
and two connections are provided through a first wall of the said at least one tank for said second fluid to pass into and from said at least one inner space, in said at least one tank, respectively;
one of said connections being positioned in a first of said part spaces, and the other of said connections is positioned in a second of said part spaces, both connections being in a part of the tank lower than said upper part of the tank where the part spaces are in fluid communication with each other.

A heater for heating water of such a construction can allow hot water to be provided directly on tapping, even after a long period of standstill without any need for hot water. The heater or cooler can be used for heating or cooling any fluid so that such a heated or cooled fluid may be provided directly even after a longer period without any demand for the heated or cooled fluid. At the same time the heat transfer between the working fluids in the heater and/or cooler can be good under all service conditions, with the strength characteristics being good for both the tank of the heater and/or cooler and for single plates in the core of plates and the material consumption being small.

Some embodiments of the invention are described in more detail below with reference to the accompanying drawings, in which:-

Figure 1 shows, in a perspective view and partly in cross section, a heater and/or cooler according to the invention.

Figure 2 shows in a front view an alternative mode of execution of a heater and/or cooler according to the invention.

Figure 3 shows a cross section through the heater and/or cooler along the line A-A in figure 2.

Figure 4 shows a cross section through the heater and/or cooler along the line B-B in figure 2.

Figure 5 shows a cross section through the heater and/or cooler along the line C-C in figure 2.

Figure 6 shows a cross section through the heater and/or cooler along the line D-D in figure 2.

Figure 7 shows a cross section through the heater and/or cooler along the line E-E in figure 2.

Figure 8 shows in a view from above the heater and/or cooler in figure 2.

Description of modes of execution

The heater and/or cooler 1 in figure 1, intended for heating tap hot water, consists of a tank 2 with an inner space 3 housing tow plate heat exchangers 4a, 4b. The plate heat exchanger 4a comprises a core of plates with a plurality of heat exchanging plates 5a and two

end plates

6a, 7a. In a corresponding way the plate heat exchanger 4b comprises a core of plates with a plurality of heat exchanging plates 5b and two

end plates

6b, 7b.

Each one of the two front (the two nearer ones in the figure)

end plates

6a, 6b has two

connections

8a, 9a and 9b, respectively, of which at least two

connections

8a, 9b extend fluid-tightly through the front wall of the tank 2 while the other two

connections

8b, 9a are fluid-tightly connected to one another through an outward pressing (not shown) in the tank 2, which outward pressing has the same function as a U-formed piece of pipe and fluid-tightly connects the

connections

8b and 9a in that the plate heat exchangers 4a, 4b seal against the partition wall 14 within the area of the said outward pressing and seals against the tank 2 around the said outward pressing. A construction without the outward pressing is possible, whereby a U-formed piece of pipe instead extends fluid-tightly through the front (the nearer one in the figure) wall of the tank 2 or through the partition wall 14. The plate heat exchangers 4a, 4b then do not need to seal completely against the partition wall 14 or against the tank 2. By fluid-tightly in this connection it is meant that the fluid, in this case hot water or hot steam, which is led through the described connections do not mix with the fluid, in this case water to be heated, which is present within the tank.

The connection 8a leads to an inlet channel 10a and the connection 9a leads from an outlet channel 11a in the plate heat exchanger 4a. In a corresponding way the connection 8b leads to an inlet channel 10b and the connection 9b from an outlet channel 11b in the plate heat exchanger 4b. The inlet channel 10a and the outlet channel 11a are in fluid communication with a first set of plate interspaces in the plate heat exchanger 4a. In a corresponding way the inlet channel 10b and the outlet channel 11b are in fluid communication with a first set of plate interspaces in the plate heat exchanger 4b. The mentioned first sets of plate interspaces are constituted by every other plate interspace between the

heat exchanging plates

5a, 5b in the plate heat exchangers 4a, 4b respectively.

Further two connections 12, 13 (due to the cross section only hinted in figure 1) extend through the front wall of the tank 2 for delivery to and removal from the tank, respectively, of the fluid which is present there. The inner space 3 in the tank 2 is in fluid communication with a second set of plate interspaces in each of the two plate heat exchangers 4a, 4b. In the present case all the plate interspaces which are not part of the described first sets of plate interspaces according to above are parts of the described second sets of plate interspaces, i.e. also the interspaces present between each of the

end plates

6a, 6b, 7a, 7b and the respective

heat exchanging plate

5a, 5b, closest thereto. A partition wall 14 divides the inner space 3 into two part spaces which, however, are in fluid communication with each other in the upper part of the tank 2. The tank 2 is rectangular and its height is larger than its width or depth. The tank 2 is made of steel sheet but any other known suitable material may be used.

From the figures 2-8 an alternative mode of execution of the described heater and/or cooler is evident, whereby the reference signs from figure 1 have been kept. The tank 2 is here constituted by four, in use of the heater and/or cooler substantially vertical, hollow cylinders 18 which in the upper part of the heater and/or cooler are in fluid communication with a hollow cylinder 19 that in use of the heater and/or cooler is substantially horizontal, and in the lower part of the heater and/or cooler extends substantially horizontally and in which two plate heat exchangers 4a, 4b are housed.

Since the tank 2 basically is constructed by two pressed panels, a front one creating the front side of the heater and/or cooler, see figure 2, and a back one with the corresponding appearance but without connections, the panels must be fluid-tightly joined around the outer edges and substantially fluid-tightly joined between the hollow cylinders 18, as best seen figure 3. Even if it is more important that the panels are fluid-tightly joined between the two middle hollow cylinders 18 than between the rest of the hollow cylinders 18, a certain minor leakage generally may still be allowed between the cylinders 18. The partition wall 14 need not be higher than what corresponds to the height of the hollow space 20, as can be seen in figure 5.

An outward pressing 21 (see figure 2) has the same function as a U-formed piece of pipe and fluid-tightly connects the

connections

8b and 9a in that the plate heat exchangers 4a, 4b seal against the partition wall 14 in the area of the said outward pressing 21 and seal against the tank 2 around the said outward pressing 21. A construction without any outward pressing 21 is possible whereby a U-formed piece of pipe instead extends fluid-tightly through the front (the nearer one in figure 2) wall on the tank 2. The plate heat exchangers 4a, 4b then do not have to seal completely against the partitions wall 14 or against the tank 2. Further there are present a temperature sensor 22, an aeration nipple 23 and four suspension holes 24.

The operation of the heater and/or cooler, which in principle is the same for the two modes of execution, will now be described. Hot water or hot steam (see the continuous line 15 in figure 1) from a heat source not shown here enters the heater and/or cooler through the connection 8a, continues into the inlet channel 10a in the plate heat exchanger 4a and is divided within the first set of plate interspaces in this plate heat exchanger, passes through the plate interspaces (the line 15 marks for the sake of clearness one plate interspace only), continues out through the outlet channel 11 a and the connection 9a, continues to and through the connection 8b, continues into the inlet channel 10b in the plate heat exchanger 4b and is divided within the first set of plate interspaces in this plate heat exchanger, passes through the plate interspaces (the line 15 marks for the sake of clearness one plate interspace only), continues out through the outlet channel 11b and exits through the connection 9b, after which the water or the steam returns to the heat source for reheating.

The tap water (see the continuous line 16 in figure 1) enters the heater and/or cooler through the connection 12 and exits through the connection 13. The tap water may freely move within the second sets of plate interspaces. Due to the presence of the partition wall 14 the tap water will preferably move upwards in the right part of the inner space 3 and downwards in the left part of the same space. Over this main direction for the flow of tap water those water movements which are caused by the heating of the tap water within the plate interspaces are added. By a suitable control (not shown) a suitable temperature of the tap water which leaves the heater for use as water for showering or the like is held.

Also during periods with little or no tapping of hot water, hot water or hot steam is, at least intermittently, delivered to the two in series coupled plate heat exchangers 4a, 4b. In this way it is secured that the volume of tap water within the tank 2 and the inner space 3 due to a self circulation (see the broken lines 17 in figure 1) at all times is held at a convenient level of temperature for showering or the like. This heated water volume comes practically at once out of the heat exchanger when tapping is once again started and the volume is so adapted that the heat exchanger reaches service performance in a steady condition before the previously stored water is finished.

Compared to the prior art, the described construction has the considerable advantage that the previously heated water volume discussed in the previous section is large enough. If the thickness of the plate in the tank is kept down the manufacturing costs are small, which is possible with the mode of execution according to the figure 2-8 since the strength of the construction is sufficiently good in spite of the use of a thin panel. Since every heat exchanging plate in the plate heat exchangers only has two port holes a larger part of the areas of the plates may be used for heat exchange than has otherwise been the case. The present corrugation pattern on the plates may also be of a simple kind.

The plates are often made of steel plate with a thickness of 0,20-0,35 mm, but also other materials may be used such as for example titanium. The heat exchanging plates are often thin and the end plates thick, but also other modes of execution may exist. For example it is possible to think of the end plates not being thick but instead being of an appearance totally or partly in accordance with the present heat exchanging plates, however with the difference that port holes only are present where the mounting of connection are desired. It is also possible to use end plates of different designs at different ends of the core of plates, or even more end plates of the same or different appearances at each end of the core of plates.

The present core of plates may be permanently joined in any convenient known way, for instance by brazing, welding or gluing. When brazing the core of plates together copper braze, nickel braze or any other known braze may be used. In using the heater and/or cooler one or more of the fluids may be something other than water. For example it is possible to think of heat exchange between oil and water. Furthermore one or several of the fluids may move in another direction through the heater and/or cooler than has been described above. Thus, the flow direction may be reversed for the said first fluid or for the said second fluid or for the said first and second fluids at the same time.

Claims

Heater and/or cooler comprising at least one tank (2) with at least one inner space (3) and at least two plate heat exchangers (4a, 4b) for at least two heat exchanging fluids, each of the plate heat exchangers (4a, 4b) being permanently joined and comprising at least one core of plates with a plurality of heat exchanging plates (5a, 5b) and at least two end plates (6a, 6b, 7a, 7b), first and second sets of plate interspaces being formed between the heat exchanging plates (5a, 5b) of each heat exchanger (4a, 4b) wherein
each heat exchanging plate (5a, 5b) having one or more corrugations extending between spaced apart, parallel first and second planes, which planes are substantially parallel with all the heat exchanging plates (5a, 5b) as well as the end plates (6a, 6b, 7a, 7b),
each heat exchanging plate (5a, 5b) having at least two port holes for forming through the core of plates at least one inlet channel (10a, 10b) and at least one outlet channel (11a, 11b) for at least one of the fluids, a first inlet channel (10a, 10b) and a first outlet channel (11a, 11b) being intended for a first fluid, and being in fluid communication with the first set of plate interspaces,
the end plates (6a, 6b, 7a, 7b) having port holes respectively communicating with the said at least one inlet channel (10a, 10b) and the said at least one outlet channel (11a, 11b), and
the said at least two plate heat exchangers (4a, 4b) being housed in the said at least one tank (2), with the second set of plate interspaces being in fluid communication with the said at least one inner space (3) in the said at least one tank (2),
the said at least one tank (2) containing a second fluid,
wherein
at least one partition wall (14) divides the said at least one inner space (3) into part spaces that are in fluid communication with each other at an upper part of the tank, whereby fluid may pass freely between said part spaces at the upper part of the tank (2),
each of the part spaces accommodates at least one of the plate heat exchangers (4a, 4b),
and two connections (12, 13) are provided through a first wall of the said at least one tank (2) for said second fluid to pass into and from said at least one inner space (3), in said at least one tank (2), respectively,
one (12) of said connections being positioned in a first of said part spaces, and the other (13) of said connections is positioned in a second of said part spaces, both connections (12, 13) being in a part of the tank (2) lower than said upper part of the tank (2) where the part spaces are in fluid communication with each other.
Heater and/or cooler according to claim 1, wherein said first set of plate interspaces includes every other plate interspace in the said at least two plate heat exchangers (4a, 4b).
Heater and/or cooler according to claim 2, wherein the plate interspaces of the second set of plate interspaces are arranged alternately with the plate interspaces of the first set.
Heater and/or cooler according to claim 3, wherein the second set of plate interspaces also includes at least one interspace defined between one of the end plates (6a, 6b, 7a, 7b) and the heat exchanging plate (5a, 5b) closest thereto.
Heater and/or cooler according to any of the preceding claims, wherein a first connection (8a) through a first wall on the said at least one tank (2) is connected to the said first inlet channel (10a) and a second connection (9b) through the first wall is connected to the said first outlet channel (11b).
Heater and/or cooler according to any one of the preceding claims, wherein the part spaces are of substantially the same size.
Heater and/or cooler according to any of the preceding claims, wherein the first outlet channel (11a) of the first of the at least two plate heat exchangers (4a) is connected to the said first inlet channel (10b) of the second of the at least two plate heat exchangers (4b) for said first fluid to enter the first inlet channel (10a) in the said first plate heat exchanger (4a) via a first connection (8a) through a first wall of the said at least one tank (2), pass through the two in series connected plate heat exchangers (4a, 4b) and then exit from the said first outlet channel (11b) in the said second plate heat exchanger (4b) via a second connection (9b) through the said first wall.
Heater and/or cooler according to any of the preceding claims, wherein the said tank (2) is of a substantially rectangular form.
Heater and/or cooler according to any of the claims 1-10, wherein the said tank (2) comprises at least two, hollow cylinders (18) which in use of the heater and/or cooler are substantially vertical and which in the upper part of the heater and/or cooler are in fluid communication with a hollow cylinder (19) that in use of the heater and/or cooler is substantially horizontal, in a lower part of the heater and/or cooler the hollow cylinders being in fluid communication with a hollow space (20) which, in use of the heater and/or cooler extends substantially horizontally and which houses the said plate heat exchangers (4a, 4b).
Heater and/or cooler according to any of the preceding claims, wherein the height of the tank (2) is larger than its width or depth.