EP3098553A1 - Plate heat exchanger system - Google Patents

Abstract

The present invention relates to a plate heat exchanger system comprising a plate heat exchanger (10) having an inlet (11) and an outlet (12) of a primary circuit (13), an inlet (14) and an outlet (15) of a secondary circuit (16), at least one Plate (17), which separates the two circuits in a housing of the plate heat exchanger, and preferably a pipeline which connects the primary circuit with a heater. To improve the heat transfer between the primary circuit (13) and the secondary circuit (16) the plate heat exchanger (10) according to the invention in the direction of gravity (G) arranged so that the plane (E) in which the plate (17) is located relative to the Gravity vector (G) and the horizontal (H) is inclined.

Description

The present invention relates to a plate heat exchanger system with a plate heat exchanger having an inlet and an outlet of a primary circuit, an inlet and an outlet of a secondary circuit and at least one plate which separates the two circuits within a housing of the plate heat exchanger. Furthermore, the plate heat exchanger system comprises a pipeline which connects the primary circuit to a heating device.

The aim of such a plate heat exchanger is the fluidic separation between the fluid of the secondary circuit to be heated and the fluid of the primary circuit which introduces this heat. This can be, for example, a fluid adapted for heat transfer and convective passage, to which, for example, corrosion inhibitors or the like are added. The fluid from the secondary circuit, however, is consumed regularly. Occasionally, special demands are placed on the quality of this fluid, especially when the fluid is to be removed as drinking or service water from the secondary circuit.

The plate heat exchangers in such a plate heat exchanger system are usually designed as countercurrent heat exchangers. In the prior art, it is known to install the plate heat exchanger lying vertically or horizontally. In this installation position, the plate heat exchangers tend to calcification, as after a tapping process, the temperature compensation takes place only by heat conduction and thus very slowly. The hotter portion of the fluid (s) during the tapping process remains hot for a long time. So there is the problem of calcification of the housing of the heat exchanger.

From the DE 20 2008 003 349 U1 a plate heat exchanger is known, which is basically vertical, to counteract the aforementioned problem of decalcification. The plate heat exchanger is aligned so that a surface normal to the plates of the heat exchanger is perpendicular to the gravitational field of the earth. Meanwhile, the housing of the plate heat exchanger is pivoted about this surface normal, so that the housing is inclined. The inlet of the primary circuit and the outlet of the secondary circuit are provided in the region of the bottom of the heat exchanger. Due to the inclination is that amount of cold water that remains after the purchase of hot water in the housing of the heat exchanger, below the outlet of the secondary circuit in the case. With the next reference of hot water on the secondary side, therefore, not the cold amount of water is first issued.

From the DE 10 2010 018 086 A1 is known a plate heat exchanger, which is based on an orientation of the plates as they are made of DE 20 2008 003 349 U1 is known, builds. So is also in the DE 10 2010 018 086 A1 a surface normal to the plates of the heat exchanger perpendicular to the gravitational field of the earth, however, differs from that of the DE 20 2008 003 349 U1 known orientation in that the longitudinal axis of the plates includes a larger angle with the gravitational field vector. Furthermore, the warm end of the plate heat exchanger, ie the inlet for the warmer medium, is provided at the upper end of the plate heat exchanger with respect to the longitudinal axis of the plates and the cold end, ie the inlet for the colder medium, at the lower end.

The two solutions after the DE 20 2008 003 349 U1 and the DE 10 2010 018 086 A1 are also characterized by the fact that the channels of the plate heat exchanger are arranged vertically relative to the gravitational direction.

But also from the DE 20 2008 003 349 U1 and the DE 10 2010 018 086 A1 Previously known solutions still need to be improved. Because even these solutions counteract the calcification insufficient.

The present invention seeks to provide a plate heat exchange system which more effectively addresses the problem of calcification and avoids it in the best possible way.

To solve the problem, the present invention proposes a plate heat exchange system having the features of claim 1. This system differs from the prior art in that the plate heat exchanger is arranged in the direction of gravity so that the plane in which the plate is inclined relative to the gravity vector and the horizontal.

Typically, plates of a plate heat exchanger have corrugated or otherwise deformed sections so that such plate does not form a completely flat surface. In particular, therefore, as the plane in which the plate lies, the plane in the space to be understood that includes the surface portions of the plate which were not deformed in the provision process of the plate. Preferably, the proportion of the surface sections the plate, which has not been deformed and therefore lying in one plane, at least 10%, preferably at least 50% and more preferably at least 85% of the total area of the plate. If the plate is deformed over its entire surface, then two directions L and B (usually also referred to as length and width) can be determined, in which the plate has its greatest extent. If the plate is deformed over its vast or entire surface or can not make up a flat surface portions in which the sheet material of the plate has not been deformed, then in particular as a plane in which the plate is to understand that level in space, the the two vectors pointing in the direction of L and B, is spanned. According to the present invention, a surface normal to the plane in which the plate is located is accordingly provided obliquely to the gravitational field of the earth, ie at an angle greater than 0 ° and less than 90 °. The plate heat exchanger of the plate heat exchanger system according to the invention usually has a plurality of such plates, which are provided lying in parallel planes and stacked one above the other and fluidly decouple the primary circuit of the secondary circuit and divide inside the housing alternately compartments for the primary circuit and the secondary circuit. If, after drawing warm water from the secondary circuit, the flow is stopped here, there is still some fluid still to be heated and some already heated fluid in the heat exchanger.

For the following clarification of the concept underlying the invention, it is assumed that the fluid is hot water, which flows through the heat exchanger on the primary side on the primary side in the gravitational field of the earth from bottom to top. This hot water is thus the fluid of the primary circuit. The water of the secondary circuit is conducted in countercurrent thereto, i. flows in the gravitational field of the earth from top to bottom. If this reference is stopped after a supply of warm water from the secondary circuit, relatively cold water is present in the input area of the secondary circuit (ie usually in the gravitational field of the earth above), whereas the water on the outlet side (ie usually in the gravity field) Earth below) is relatively warm.

The cold water displaces the warm water with a lower density in the Earth's gravity field due to the higher density. Due to the inclination of the heat exchanger, the water meets relatively soon in the Gefach on a the corresponding Gefach the Heat exchanger delimiting wall formed by a plate. This plate can also be formed by an outer housing wall of the heat exchanger housing. This stops the downward movement of the cold water. The cold water now slides down the sloping surface. This results in a microcirculation in the region of the respective Gefaches. Countercurrent to the cold water, due to the continuity of the medium in the same or an adjacent compartment, relatively warm water flows upwardly. For the flow in a compartment, some mixing takes place due to circulations at the interface between the falling and the rising water. Moreover, if the plate heat exchanger is a heat exchanger with a plurality of parallel plates and a plurality of alternating compartments on the one hand for the primary and on the other for the secondary circuit - the fluid of the secondary circuit also slightly through in the underlying Gefach the primary circuit befindliches warmer fluid heated. Thus, an effective Vergleichmäßigung the temperature of the first in the Gefach when stopping the circulation of existing fluid of different temperature is achieved. If water has been used as fluid above, this merely takes into account the circumstance that this fluid is usually conducted at least in the secondary circuit. However, the invention is not limited to this fluid.

According to a preferred embodiment of the present invention, the plate heat exchanger in the direction of gravity is arranged so that a surface normal to the plane in which the plate is inclined by an angle of 9 to 50 ° to the gravity vector, particularly preferably with an angle of between 10 ° or 30 ° as the lower limit and 50 ° or 60 ° as the upper limit, and more preferably at the angle between 15 ° and 35 °. The optimum would be given for a plate heat exchanger whose surface normal to the plane in which the plate is inclined by an angle of 25 ° ± 5 ° to the gravity vector.

The plate heat exchanger is usually incorporated in a heat exchanger system, which has at least one removal for drinking or service water. Thus, the plate heat exchanger system according to a preferred embodiment of the present invention, a corresponding line that is part of the secondary circuit and leads to a withdrawal point for drinking or service water.

As already mentioned, the fluid of the primary heating circuit in the heat exchanger preferably flows uphill so against gravity and the fluid of the secondary circuit flows in the heat exchanger opposite. The heat exchanger is thus a countercurrent heat exchanger. If the supply of water is stopped, the cold water of the secondary circuit flows accordingly first downwards until it encounters the oblique boundary surface, which bounds the corresponding compartment below. This boundary surface may be formed by a plate in the interior of the housing or just by the housing of the heat exchanger. If the circulation of the circulating in the primary circuit fluid is stopped, this also falls in the same way and approaches that area of the compartment in which relatively warmer fluid is provided. Thus, with the said preferred development, a relatively uniform temperature is rapidly set in both compartments, as long as the flow in the heat exchanger comes to a standstill.

The primary circuit is preferably in the housing above the secondary circuit. In particular, in a heat exchanger with only one Gefach for each of the circuits is thus ensured that the relatively colder fluid in the primary circuit in the direction of the even colder fluid in the secondary circuit initially drops and thus a certain convective heat transfer at the boundary layer between the two circuits and through the plate separating the two circuits. Usually, in the plate heat exchanger, a plurality of compartments are arranged one above the other, which are regularly associated alternately with the primary and secondary circuit. The previously discussed development requires that the top Gefach a compartment of the primary circuit is provided and at the bottom of a compartment of the secondary circuit.

According to another preferred embodiment of the present invention, the housing of the plate heat exchanger is inclined. The inclination of the plate heat exchanger housing usually corresponds to the inclination of the individual plates of the housing. Accordingly, the plates of the housing are aligned parallel to the longitudinal extent of the heat exchanger housing. The housing has a primary circuit bleed valve and a secondary circuit bleed valve. It goes without saying that these vent valves are provided at the upper edge of the housing in the vertical direction.

A simplified connection of pipelines of the primary and secondary circuit according to the present invention is improved in that the housing of the plate heat exchanger at the bottom has corresponding connections for the primary circuit and / or the secondary circuit.

According to a further preferred embodiment of the present invention, all connections for the primary and the secondary circuit are provided on the underside of the plate heat exchanger housing. All installation work to connect the piping systems must therefore be done only from the bottom. The heat exchanger with its housing can be mounted at a suitable location to further simplify this connection work.

As is apparent from the foregoing description, the present invention provides the ability to improve the cooling time within the heat exchanger, i. to shorten the time that is necessary to provide him to the two circuits within the heat exchanger housing in each case substantially constant temperature conditions over the entire volume extension to the respective circuits. This counteracts the problem of increased calcification of the compartments in the heat exchanger and thus of the heat exchanger as a whole. The inclination of the at least one plate ultimately leads to a kind of circular convection flow within the compartment to one of the circuits, which causes the best possible Vergleichmäßigung the temperature in that Gefach. Thus, in the respective Gefach quite quickly a uniform mixing temperature is achieved, which represents the temperature of the fluid in the Gefach respectively in the entire heat exchanger, which adjusts after mixing the different temperature fluid fractions in one of the circuits within the heat exchanger.

Fig. 1

eine perspektivische Seitenansicht eines Ausführungsbeispiels eines Plattenwärmetauschers und

Fig. 2

eine schematisierte Systemdarstellung eines Ausführungsbeispiels eines Plattenwärmetauschersystems.

Further advantages and features of the present invention will become apparent from the following description of an embodiment in conjunction with the drawings. In this show:

Fig. 1

a side perspective view of an embodiment of a plate heat exchanger and

Fig. 2

a schematic system representation of an embodiment of a plate heat exchanger system.

Fig. 1 illustrates a perspective side view of an embodiment of a plate heat exchanger 10 having an inlet 11 and an outlet 12 of a primary circuit 13, an inlet 14 and an outlet 15 of a secondary circuit 16 and a direction indicated by a dashed line plate 17, which separates the two circuits 13, 16 from each other ,

The plate 17 separates the interior of a marked with reference numeral 18 housing the plate heat exchanger 10 in two compartments 19, 20. The Gefach 19 is the flow area for the flowing fluid in the primary circuit. In the compartment 20, the fluid of the secondary circuit 16 flows through the housing 18. As can be seen, the inlet 11 of the primary circuit and the outlet 15 of the secondary circuit located at the bottom of the housing 18 near an edge which is defined by a front end of the housing 18. The outlet 12 of the primary circuit and the inlet 14 of the secondary circuit are located at the opposite end of a bottom of the housing 18. This bottom is defined by a side wall 21 of the housing 18. The Gefach 19 for the primary circuit 13 is the upper side bounded by an upper side wall 22 of the housing. This upper side wall 22 of the housing is provided at its upper end near the end face by two vent valves 23, 24. It is understood that a plurality of compartments of the type described above in the plate heat exchanger one above the other and alternately arranged. Only one Gefach was shown enlarged, in order to express the essence of the invention more clearly. The respective compartments communicate at the end with the inlets 11, 14 and outlets 12, 15.

In FIG. 1 the horizontal is marked by a line H. The inclination of the housing, that is, the parallel walls 21, 22 relative to this horizontal H is marked with the angle α. In the present case α = 35 °. With a corresponding angle and the plate 17 is inclined relative to the horizontal H. At right angles to this, G indicates the gravitational field of the earth. The partition plate 17 has a surface normal N which is at the same angle α to the vector G of the earth's gravity field.

The FIG. 2 shows the installation situation of the in Fig. 1 illustrated embodiment with the connecting lines connected to corresponding hot water (DHW) lines, for cold drinking water, which is provided via the house connection (TWK HA), for heating water (Hzg.), where VL indicates the flow and RL the return are. The heating pipes with the further index Whg. Are connected to the apartment and are flow and return for the residential unit. The corresponding line strands are numbered by the reference numerals 1 to 7. A wiring harness 8 connects the inlet 14 of the secondary circuit for drinking water of the plate heat exchanger 10 with a branch to which the lines 2 and 3 are connected. The outlet of the secondary circuit 15 is connected to the line 1. The inlet of the primary circuit 11 is connected via a tee with the line 4 for the heating flow. The outlet 12 of the primary circuit communicates via the line 9 and a three-way valve with the line 5 for the heating return, which can also be connected via the three-way valve with the coming out of the apartment return line 7 of the heater. The lines 5 and 4 lead the heating water via a boiler, not shown, in which the heating water is heated.

Thus, the conceivable installation situation of the plate heat exchanger in the in FIG. 2 illustrated plate heat exchanger system exemplified.

In the FIG. 1 Plotted flow arrows show the circulation due to free convection after switching off any flow due to forced convection, which leads to a rapid temperature compensation within the heat exchanger, due to the inclined orientation of the individual compartments 19, 20 bounding walls. The relatively high upright very cold fluid of the primary circuit 13 has a higher density than the underlying, slightly warmer fluid of the same circuit 13. The same applies to the area located in the inlet 14 relatively cold fluid of the secondary circuit 16 in relation to the near Outlet 15 arranged fluid of the same circuit. Due to the higher density, the colder fluid has a greater tendency to sink. When descending it presses the relatively warm fluid of the same Gefaches 19 and 20 upwards. The result is a microcirculation due to the different densities, which comes to a standstill only when the temperature within the compartments is substantially unified. Thus results in the solution according to the invention a faster temperature compensation and thus a lower calcification.

In FIG. 2 is entered at the height of the plate 17 whose length is L and whose width is B in the form of direction vectors. In this case, the direction vector L indicates the direction of the greatest extension, that is to say the longitudinal extent of the plate 17, and the vector B the direction of the extent of the plate in the second largest direction, that is to say the width direction. In the present case, the vectors L and B span a plane E to which the surface normal N is oriented orthogonally. In this case, the present flat plate 17 is completely within this plane E and defines this plane E itself.

LIST OF REFERENCE NUMBERS

10

Plate heat exchanger

11

Inlet of the primary circuit

12

Outlet of the primary circuit

13

Primary circuit

14

Inlet of the secondary circuit

15

Outlet of the secondary circuit

16

Secondary circuit

17

plate

18

casing

19

Compartment for primary circuit 13

20

Compartment for secondary circuit 16

21

Lower side wall

22

Upper side wall

23

vent valve

24

vent valve

G

The direction of gravity

H

horizontal

N

surface normal

α

Angle of inclination

L

Direction of the largest extent

B

Direction of the second largest expansion

e

level

Claims (9)

Plate heat exchanger system comprising a plate heat exchanger (10) having an inlet (11) and an outlet (12) of a primary circuit (13), an inlet (14) and an outlet (15) of a secondary circuit (16), at least one plate (17), which separates the two circuits in a housing of the plate heat exchanger, and preferably a pipeline which connects the primary circuit with a heating device,
characterized,
that the plate heat exchanger (10) in the direction of gravity (G) is arranged so that the plane (E) in which the plate (17) is located, relative to the gravity vector (G) and the horizontal (H) is inclined. Plate heat exchanger system (10) according to claim 1, characterized in that a surface normal (N) on the plane (E), in which the plate (17) is located, relative to the gravity vector (G) by an angle (α) of between 9 ° tilted to 50 °. Plate heat exchanger system (10) according to claim 2, characterized in that the angle (α) is in a range between 10 ° to 60 °. Plate heat exchanger system (10) according to one of the preceding claims, characterized in that the secondary circuit (16) has a leading to a removal point for drinking or service water lines. Plate heat exchanger system (10) according to one of the preceding claims, characterized in that the fluid of the primary heating circuit opposite to gravity and the fluid of the secondary circuit (16) flows in opposite directions. Plate heat exchanger system (10) according to one of the preceding claims, characterized in that in the housing at least one Gefach the primary circuit (13) is arranged above the secondary circuit (16). Plate heat exchanger system (10) according to one of the preceding claims, characterized in that the housing of the plate heat exchanger (10) aligned inclined is and to the primary circuit (13) and the secondary circuit (16) each have a vent valve (23, 24). Plate heat exchanger system (10) according to any one of the preceding claims, characterized in that the housing (18) of the plate heat exchanger (10) on the underside connections for the primary circuit (13) and the secondary circuit (16). Plate heat exchanger system (10) according to any one of the preceding claims, characterized in that all connections for the primary circuit (13) and the secondary circuit (16) on the underside (21) of the housing (18) are provided.

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