U.S. patent application number 10/149700 was filed with the patent office on 2003-06-12 for water heater comprising a plate heat exchanger and a storage container for heated water.
Invention is credited to Andersson, Sven, Dahlberg, Thomas, Fogelberg, Lars, Folkelid, Magnua, Rissler, Per, Sanner, Bengt-Ove.
Application Number | 20030108344 10/149700 |
Document ID | / |
Family ID | 20418154 |
Filed Date | 2003-06-12 |
United States Patent
Application |
20030108344 |
Kind Code |
A1 |
Andersson, Sven ; et
al. |
June 12, 2003 |
WATER HEATER COMPRISING A PLATE HEAT EXCHANGER AND A STORAGE
CONTAINER FOR HEATED WATER
Abstract
A water heater adapted to avoid peak temperatures of delivered
water comprises a plate heat exchanger (1) connected to a storage
container (2) provided with interior reinforcing means (9-11. FIG.
1; 13-13'". FIGS. 5-18) connecting opposite parts of the outer wall
(2') of the container (2). Even provided with a thin storage
container wall this makes it possible to use a box shaped water
heater design without risk of deformations due to variations in the
water pressure. The reinforcing means may consist of stacked
interconnected plates (13-13'"). e.g. having the same form and size
as plates (12-12'") used in a plate heat exchanger connected to the
container (2).
Inventors: |
Andersson, Sven;
(Kungsgatan, SE) ; Dahlberg, Thomas; (Brommassian,
SE) ; Fogelberg, Lars; (Ekslogatan, SE) ;
Folkelid, Magnua; (Bulow Hubes vag, SE) ; Rissler,
Per; (De la Rose, SE) ; Sanner, Bengt-Ove;
(Mistelgatan, SE) |
Correspondence
Address: |
Breiner & Breiner
115 North Henry Street
PO Box 19290
Alexandria
VA
22320-0290
US
|
Family ID: |
20418154 |
Appl. No.: |
10/149700 |
Filed: |
June 14, 2002 |
PCT Filed: |
December 13, 2000 |
PCT NO: |
PCT/SE00/02510 |
Current U.S.
Class: |
392/450 ;
392/451 |
Current CPC
Class: |
F28F 2225/00 20130101;
F28D 9/005 20130101; F28D 2020/0021 20130101; F24D 3/087 20130101;
F28D 20/0034 20130101; F24D 11/002 20130101; Y02E 60/14
20130101 |
Class at
Publication: |
392/450 ;
392/451 |
International
Class: |
H05B 003/78 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 1999 |
SE |
9904610-4 |
Claims
1. A water heater (1, 2) comprising a plate heat exchanger (1) and
a storage container (2) for heated water, the said storage
container (2) being provided with an outer limiting wall (2'), an
exit opening (7) for delivery of the heated water and reinforcing
means (9-11, FIG. 1, 13-13'" FIGS. 5-18) adapted to interconnect
opposite parts of the wall (2') for force transnission in three
directions perpendicular to each other, characterized in that that
said reinforcing means in the storage container (2) are stacked
plates (13-13'", FIGS. 5-18) provided with ridges and depressions
and are interconnected by brazing, soldering, welding or gluing,
the said plates being provided with openings forming channels (3',
3", 3'", 3"") through which heated water may flow.
2. A water heater according to claim 1, characterized in that its
outer shape and size of the storage container in two perpendicular
directions are mainly equal to corresponding shape and size of the
heat exchanger (1) connected to the container (2).
3. A water heater according to claim 2, characterized in that the
storage container (2) is designed as a conventional two-circuit
liquid to liquid plate heat exchanger in which only one circuit is
used (FIGS. 5-11).
4. A water heater according to claim 2, characterized in that it is
designed as a conventional two-circuit liquid to liquid plate heat
exchanger except for one end plate (30, FIGS. 16-18) being shaped
to provide connections (31, 32) between the two circuits.
5. A water heater according to one of the claims 1-4, characterized
in that the storage container (2) is integral with the plate heat
exchanger (1) supplying the heated water (FIGS. 5-18).
Description
[0001] The present invention relates to a water heater comprising a
plate heat exchanger and a storage container for heated water.
[0002] Hot water, in particular sanitary water, is often obtained
by passing cold water through a plate heat exchanger to which a hot
fluid is supplied in a secondary circuit. For household use the
temperature at the tap should be kept constant e.g. between 55 and
60.degree. C. In many applications it is desired to heat the water
directly in accordance with the flow needed so as to avoid
unnecessary storing. However, some storage is unavoidable viz. the
amount of water in the plate heat exchanger and the tubing to the
taps. The use of plate heat exchangers makes it possible to obtain
an efficient heat exchange and to supply a great mass flow of
heated water with a minimum of storage volume. A problem inherent
in the system is that if hot water has been tapped for some time
followed by a short interval without flow, a new hot water flow
will cause the temperature of the first amount of water to become
substantially higher than desired. Hot water supplied at a
temperature above 60.degree. C. may be dangerous if used e.g. for
washing babies. The high water temperature is due to the fact that
the fluid heating the water in the plate heat exchanger must have a
temperature 10-20.degree. C. higher than the desired temperature of
the water to be tapped. When the flow through the heat exchanger is
stopped the sanitary water present in the exchanger will be heated
to the temperature of the heating fluid in the exchanger. For
reasons of safety a storage container for the hot water could be
provided between the heat exchanger and the taps. A long tubing
between the exchanger and the taps may constitute such container.
However, such tubing may not be practical to provide and is
certainly not desired as the first amount of water delivered to a
tap after no use of hot water during a long period will be rather
cold.
[0003] Therefore, it is desired to provide a water heater which has
a small volume, but still prevents peak temperatures of the hot
water when starting tapping after a short stop interval following a
longer tapping period. Besides a small volume the water heater
should also have small outer dimensions. In most cases the use of
spherically shaped containers is impossible and other shapes may be
deformed by the comparatively high water pressures which may
occur.
[0004] The use of heavy walled containers is prohibited for cost
reasons. A water heater comprising a plate heat exchanger and a
storage container for heated water, the said storage container
being provided with an outer limiting wall, an exit opening for
delivery of the heated water and reinforcing means adapted to
interconnect opposite parts of the wall for force transmitting in
three directions perpendicular to each other is according to the
invention characterized in that said reinforcing means in the
storage container are stacked plates provided with ridges and
depressions and are interconnected by brazing, soldering, welding
or gluing, the said plates being provided with openings forming
channels through which heated water may flow.
[0005] Such reinforcing means make it possible to design the
container with extremely thin walls, and still allow high internal
pressures without deformations. The container is not bound to be of
spherical or cylindrical shape.
[0006] Preferably the container may be designed with the same outer
shape and size as that of the heat exchanger in two directions
perpendicular to each other--making it possible to mount it e.g. as
a continuation of the plate heat exchanger.
[0007] The container could be designed as a conventional
two-circuit liquid to liquid plate heat exchanger in which only one
circuit is used. However, both circuit passages could be used
advantageously, if at least one plate therein is shaped to provide
a connection between the two circuits.
[0008] Most preferably the container could be designed so as to
form an integral part of the plate heat exchanger supplying the
heated water to be stored in the container.
[0009] The invention will be described in more detail reference
being made to the accompanying drawings in which
[0010] FIG. 1 illustrates the basic principle of the present
invention and is a vertical section through a water heater showing
the principle of operation used in water heaters according to the
invention, the section being taken along the line I-I of FIG.
3.
[0011] FIG. 2 is a right hand side end view of plate heat exchanger
part of the water heater shown in FIG. 1 seen in the direction of
the arrows II-II of FIG. 1.
[0012] FIG. 3 is a left hand side end view of FIG. 1 seen in the
direction of the arrows III-III in FIG. 1.
[0013] FIG. 4 is vertical section along the line IV-IV in FIG.
3.
[0014] FIG. 5 is a section along the line V-V in FIG. 7 showing an
embodiment of a water heater according to the invention in which a
container for heated water has been integrated with a plate heat
exchanger.
[0015] FIG. 6 is a section along the line VI-VI in FIG. 7.
[0016] FIG. 7 is a left hand end view of the device of FIG. 5 seen
in the direction of the arrows VII-VII in FIG. 5.
[0017] FIG. 8 is a right hand end view of the device shown in FIG.
5 seen in the direction of the arrows VIII-VIII of FIG. 5.
[0018] FIGS. 9 and 10 show sections along the lines IX-IX resp. X-X
of FIG. 7.
[0019] FIG. 11 is an exploded, perspective view of the water heater
illustrated in FIGS. 5 to 10 showing the working principle of the
device.
[0020] FIG. 12 is a vertical section through a further embodiment
of the invention, the section following the line XII-XII of FIG.
14.
[0021] FIG. 13 is a section through the same device along the line
XIII-XIII of FIG. 14.
[0022] FIG. 14 is a left hand side end view of the device shown in
FIG. 12 seen in the direction of the arrows XIV-XIV of FIG. 12.
[0023] FIG. 15 is a right hand side end view of the device of FIG.
12 seen in the direction of the arrows XV-XV in FIG. 12.
[0024] FIG. 16 is a section along the line XVI-XVI of FIG. 14.
[0025] FIG. 17 is a section along the line XVII-XVII of FIG.
14.
[0026] FIG. 18 is an exploded, perspective view of the water heater
illustrated in FIGS. 12 to 17 showing the working principle of the
device.
[0027] The FIGS. 1-4 show the general operating principle used in
the present invention. In FIG. 1 a plate heat exchanger has been
designated by an arrow 1 and is connected to a storage container 2
by a tube 3. The heat exchanger 1 is of the known two-circuit plate
type having an inlet 4 for a fluid to be heated--in the actual case
a sanitary flow of water. The heated water leaves the heat
exchanger 1 via the tube 3. The heating is obtained by exchanging
heat with a hot water circuit having an inlet 5 and an outlet 6
shown in FIGS. 3 and 4. The storage container 2 has an outer
limiting wall 2' provided with an outlet tube 7 governed by a valve
8 The inlet 4 to the circuit of sanitary water in the pate heat
exchanger 1 is connected e.g. to the urban water works system. The
hot water circuit includes a boiler--not shown--connected to the
inlet 5 and the outlet 6 of the heat exchanger 1.
[0028] During operation of the system--i.e. when sanitary water is
tapped by opening the valve 8--cold sanitary water enters the heat
exchanger 1 via the inlet 4 and is fed to the container 2 after
being heated from e.g. 10.degree. C. to 55.degree. C.
Simultaneously the flow of heating hot water may enter the inlet 5
of the heat exchanger 1 at a temperature of 80.degree. C. and leave
the outlet 6 at a temperature of 65.degree. C. In case the tapping
of hot sanitary water is stopped for a period of e.g. a few minutes
and then restarted, the sanitary water contained inside the heat
exchanger 1 during the period when there is no flow of sanitary
water will leave the exchanger 1 at a temperature which could be as
high as 70.degree. C. This would be harmful if used directly to
wash human beings--especially small children. Therefore, the
container 2 has been provided between the heat exchanger 1 and the
valve 8 The volume of the container 2 should be sufficiently great
to hold the quantity of sanitary water necessary to avoid the peak
in temperature. The space available will normally be used most
economically by shaping the container 2 as a box having the same
height and width as that of the heat exchanger 1. Due to the great
variations in the interior pressure a box shaped container will
become detrimentally deformed unless provided with a very thick
wall. This is impossible from an economic point of view. According
to the present invention the wall 2' of the container 2 may be very
thin because opposite wall parts of the box shaped container 2
according to the invention have been interconnected by reinforcing
means 9, 10, and 11 able to transmit force in three directions
perpendicular to each other. The reinforcing means are shown
schematically only.
[0029] According to the invention the reinforcing of the container
wall 2' is established by providing the container 2 with interior
stacked plates having pressed patterns of ridges and depressions
and brazed, soldered or glued together--in a way similar to the
traditional way of manufacturing plate heat exchangers. The
container 2 is preferably given the same outer dimensions as that
of the heat exchanger 1 in two directions and it may therefore be
manufactured as a continuation of the heat exchanger 1.
[0030] An embodiment of this type of water heater has been shown in
FIGS. 5 to 10 and the flow principle is illustrated in FIG. 11. The
water heater shown in FIGS. 5 to 10 is an integrated heat exchanger
1 and container 2. FIG. 5 is a section along the line V-V of FIG.
7, which in turn is a left hand end view of FIG. 5 in the direction
of the arrows VII-VII in FIG. 5. The section of
[0031] FIG. 5 shows the flow of sanitary water entering the heat
exchanger part 1 via the inlet 4 and flowing downwards between
pairs of heat exchanger plates 12 to a manifold space 3 connected
to a corresponding manifold space 3' at the bottom of the container
part 2. The sanitary water is now passing upwards between pairs of
plates 13 and will leave the container part 2 via an outlet 7
provided with a valve 8. A separating plate 14 prevents the flow of
sanitary water from passing directly from the inlet 4 to the outlet
7.
[0032] FIG. 6--which is a section through the inlet 5 and the
outlet 6 for the heating medium of the heat exchanger 1, said
section being taken along the line VI-VI of FIG. 7--illustrates the
circuit of heating medium entering via the inlet 5, flowing upwards
between pairs of plates 12 and leaving the exchanger 1 via the
outlet 6. The plate 14 will separate the heat exchanger 1 from the
container 2 by preventing the heating medium from entering void
spaces 15 in the container 2.
[0033] FIGS. 9 and 10 which are sections along the lines IX-IX
resp. X-X in FIG. 7 show the outlet 6 for the heating medium resp.
the inlet 4 and the outlet 7 for sanitary water as well as the
inlet 5 for the heating medium. Also the void volumes 15 are
shown.
[0034] FIG. 11 shows how an end plate 17, a stack of plates 12,
12', 12" and the separating plate 14 form the heat exchanger 1 part
according to FIGS. 5-10, while the separating plate 14, a stack of
plates 13, 13', 13" and an end plate 18 form the container part 2.
The end plate 17 is provided with an inlet 4 for the cold sanitary
water, an inlet 5 for the heating medium and an outlet 6 for the
heating medium. The space between the end plate 17 and the first
heat exchanging plate 12 is not used and a ring 19 serves as a
channel for the flow of sanitary water. The space between the first
heat exchanger plate 12 and the following plate 12' in the stack is
blocked from passage of sanitary water, but allows passage of
heating medium entering the exchanger 1 via the inlet 5. The
sanitary water is flowing downwards between the plate 12' and an
adjacent plate 12" and leaves the exchanger via the outlet manifold
part 3 and enters the container via a manifold part 3'. The spaces
between the plates 12 and 12' resp. 12" and 14 are open for upwards
flow of heating medium which leaves the heat exchanger via the
outlet 6. In FIG. 11 the heat exchanger plates are indicated as
being provided with herring bone patterns which are traditional in
plate heat exchangers.
[0035] The plates of the container part 2 of the water heater shown
in FIGS. 5 to 11 are also provided with such pattern, but they have
no heat exchanging purpose. However, it is advantageous to provide
even the plates inside the container 2 with the same herring bone
pattern--partly because a low number of different types of plates
is more economic, partly because the reinforcing effect in three
directions perpendicular to each other is easily obtained in the
container 2 when brazing the pattern provided plates together.
[0036] A first part 21 of the hot sanitary water leaving the
exchanger part 1 and entering the container 2 at 3' will now pass
upwards in a channel between the separating plate 14 and the first
plate 13 of the container 2, while a second part 22 of the hot
sanitary water will pass upwards between the plates 13' and
13"--i.e. each other channel between the plates of the container
part 2. The said second part 22 of the sanitary water rejoins the
flow 21 before leaving the container part 2 via the outlet 7. The
remaining channels in the container part 2--i.e. the channel
between the plates 13 and 13' and the channel between thc plates
13" and 18 are blocked from entry of any medium. Thus the heat
exchanger part 1 of the water heater operates as an ordinary two
flow plate heat exchanger, whereas the container part 2 serves as a
distributor for the flow of heated sanitary water dividing it and
rejoining it prior to leaving the container 2 via the outlet 7.
This will ensure that temperature peaks are avoided and it will
operate in such a way that there will be no risk of accumulations
of permanently non-flowing sanitary water.
[0037] A still further improvement of the container part 2 of the
water heater is illustrated by the embodiment of FIGS. 12 to 18.
Here, the object is to utilise the whole volume of the container 2
for dividing the flow of sanitary water exiting the heat exchanger
1.
[0038] The heat exchanger part 1 is the same as that described
above and shown in FIGS. 5 to 11, but an end plate 30 of the
container part 2 has been designed so as to provide--together with
an adjacent plate 13'"--channels 31 and 32 connecting pairs of
manifold channels through the container at its bottom and top as
will be explained later. The sanitary water entering the container
part 2 at 3' moves upwards between each other channel formed by the
plates in the container part 2. However--as shown in FIGS. 16 and
18--the channel 31 allows also a flow of sanitary water to pass
upwards through the remaining channels in the container part 2. The
upward flows of sanitary water through the container part 2 are
united in parallel manifolds 3" and 3'"--see FIG. 17--and finally
rejoined via the channel 32 before exiting the container 2 via the
outlet 7.
[0039] It will appear from FIG. 18 that the flow of hot sanitary
water entering the container part 2 at the manifold part 3'. will
be divided into a first flow 33 and a second flow 34. The first
flow 33 will pass upwards between the separating plate 14 and the
first plate 13 in the container part 2. It continues directly
through the container 2 to the outlet 7 via the manifold 3"--as
shown in FIG. 17. The second flow 34 continues through the manifold
3', but a flow part 35 is branched off and will pass upwards
between plates 13' and 13" Here, it will reach the manifold 3" and
rejoin the first flow 33. The remains of the second flow 34 will
pass through the channel 31 and will be returned in the direction
towards the heat exchanger 1 via a manifold 3""--see FIG. 16--and
pass upwards through the container part 2 to the manifold 3'" via
the remaining channels--i.e. the channels between the plates
13'"-13" and 13'-13. The sanitary water flow from the manifold 3'"
will leave the container 2 via the channel 32 to the outlet 7.
[0040] It will be understood that for reasons of clarity the FIGS.
11 and 18 have not been shown with the number of plates shown in
the corresponding FIGS. 5-10 resp. FIGS. 11-17.
[0041] It will also be understood that the water heater according
to FIGS. 11-18 --although being the more costly one--could be
preferred as having the best performance in relation to its cost of
manufacture.
* * * * *