EP0530933B1 - Heat insulated electric storage heater - Google Patents

Abstract

An electric storage heater having a heat storage core (10) with a protective housing (8), which essentially encloses the storage core (10), and having an insulator layer which provides heat insulation for the storage core (10), is arranged between the storage core (10) and the protective housing (8) and consists of a plurality of insulating panels (5, 6, 12, 13). The electric storage heater is characterised in that the surfaces of the insulating panels (5, 6, 12, 13) which make contact with the air flow of the air which is to be heated consist of non-fibrous material, and in that the insulating panels (5, 6, 12, 13) form a heat-proof surface contact on their abutting surfaces (17) in the final assembled state. <IMAGE>

Description

The invention relates to an electrical storage heater with a ceramic heat storage core. The storage core consists of a material with high specific heat, preferably magnesia stones. Due to the high specific heat, the storage core is able to absorb a relatively large amount of heat. The memory core is heated to a temperature level of around 800 ° C. Since the storage heaters are housed in living rooms, the storage cores must be heat-insulated and protected against accidental contact, because otherwise the stored heat would be released to the ambient air undesirably quickly and, on the other hand, every touch of the storage heater for the operator entails the risk of dangerous burns would.

The known electric storage heaters therefore all have an essentially closed protective housing, preferably composed of a plurality of metal sheets. The memory core is arranged so that it cannot be touched in this protective housing. An insulating layer, which preferably consists of insulating plates, is also attached between the housing inner walls and the storage core. The functionality of the electric storage heaters is as follows: The ceramic storage core is heated during the low-tariff night tariff period. The stored core slowly releases this stored heat into the ambient air to be heated up during the day. For this purpose, ambient air is sucked into the storage heater, passed over the storage core and expelled from the storage heater. The storage heater is therefore effective as a heat exchanger. To accelerate the heat exchange, a blower is also provided on the storage heater to accelerate the air flow to be heated.

Since the air flow must penetrate into the interior of the device and must also leave the inside of the device after the heat exchange, contact is made by the Air flow inevitable even with the insulating material. Such an electric storage heater is known for example from
DE-C-36 03 615.

From DE-C-36 03 615 it is also known that a mass transfer between the insulating material and the air flow is undesirable. In particular, it must be ensured that no fibrous materials get into the air flow and so pollute the ambient air. This applies all the more to carcinogenic fibers, which are usually inhaled particularly easily with the air we breathe. Such fibers generally have a diameter of up to 5 µm.

So far, two types of thermal insulation mats have been used in the known storage heaters. On the one hand, mineral fiber mats were used in places that allowed any wall thickness. These mineral fiber mats are inexpensive and, with the appropriate wall thickness, also have the required insulating properties. On the other hand, soft heat insulation mats were used in the known storage heaters in areas with limited installation space. These soft thermal insulation mats have an extremely high insulating ability and can be designed with thin walls. From DE-A-2 611 115 a boiler is known which is thermally insulated by means of elastic insulating mats. However, the soft thermal insulation mats are high quality and accordingly expensive to buy.

The mineral fiber mats mentioned have proven to be unsuitable with regard to the modern requirements, in particular the required suppression of material exchange between insulating mats and air flow.

DE-C-36 03 615 therefore proposes to manufacture at least the surfaces of an insulation block arranged below the storage core and facing the air flow from non-fibrous thermal insulation material. Microporous silicon oxide is known as a fiber-free material for soft material thermal insulation boards. For insulating hardboards, the vermiculite insulation is also made, for example
Römpp-Chemie-Lexikon, 9th edition, 1992, pp.4896f.
ISBN 3-13-735109-X, Thieme Verlag, Stuttgart known. Vermiculite is also characterized by its good formability and dimensional stability
DE-A-37 00 478
known.

Due to this high dimensional stability, these hard insulation panels are stiff and incompressible. A disadvantage of installation as insulating plates in a storage heater is that several hard insulating plates must be arranged horizontally and vertically to one another. Gaps often remain on the abutting surfaces of a vertically arranged and horizontally arranged hard insulating plate, that is to say in the region of the abutting edges of the insulating plates. These columns act as thermal bridges, so that heat escapes from the interior of the storage heater to the outside in an uncontrolled manner. So far, the sealing properties of such hard insulating plates have not been sufficient for electrical storage heating devices.

The invention is based on the problem of designing the hard insulating plates in such a way that their insulating effect also satisfies in the region of the abutting edges and such hard insulating plates are also suitable for use in storage heating devices. This object is achieved by the combination of features of claim 1.

According to claim 1, the electric storage heater according to the invention also has the known heat storage core and the protective housing surrounding the storage core. Between the storage core and protective housing, the thermal insulation layer consisting of several fiber-free insulating plates is also attached. The abutting edges of the insulating plates are designed as abutting surfaces according to the invention. As a result of this planar formation of the abutting edges, surface contact of the individual abutting surfaces occurs between two adjacent insulating plates in the final assembly state. This surface contact, which is to be dimensioned as large as possible, is effective in the manner of a surface seal. In this way, an absolutely heat-tight connection between the insulating plates is made.

According to claim 2, the abutting surfaces of the insulating plates are developed in such a way that they are formed in the manner of a matrix and a patrix and, to a certain extent, interlock in the assembled state. The abutting surfaces of the insulating plates according to claim 2 are consequently complementary to each other and interlock positively in the final assembly state. This form fit is effective in the manner of a labyrinth seal, so that the sealing effect in the joint areas is further improved.

An additional increase in the sealing effect can be achieved by the measures proposed in claims 3 to 6. According to claim 3, a deformable sealing body is between the abutting surfaces of two adjacent insulating plates. Due to the surface pressure exerted by the abutting surfaces, this sealing body clings to the abutting surfaces and thus seals fine pores and uneven surfaces. Suitable sealants are, for example, plastically deformable soft material plates (claim 4). The soft material adapts to the shape of the respective abutting surface when the neighboring insulating plates are braced against each other and thus provides a particularly good gap seal. Also suitable as a sealant is elastically deformable, inorganic fiber fabric, quartz silk fabric or high-melting glass silk fabric is preferably used. This fiber fabric is an elastic sealant and expediently has a fiber thickness of more than 5 μm. This inorganic fiber fabric according to claim 5 is further developed according to claim 6 in that it is in the form of a fabric tube. These fabric hoses are placed in the butt joints of two adjacent insulating plates and laid flat, so that a slightly resilient insulating layer is created, which additionally increases the sealing effect, in particular the gap seal.

Claims 7 to 10 relate to particularly suitable materials for the insulating plates. Vermiculite and microporous silicon oxide are particularly suitable for this. Most of the side thermal insulation boards are hard insulating boards made of inorganically bound vermiculite and the vertical, upper and lower thermal insulation boards are high-density soft-body boards made of microporous silicon oxide. However, other arrangements, combinations and materials are also conceivable both for the hard insulating boards and for the high-insulation soft-body boards and expressly form part of this invention. For the inorganic setting of vermiculite, for example, water glass, i.e. alkali silicate, can be used. The plates made of microporous silicon oxide can be produced by pressing and then sintering suitable starting materials. Claim 10 relates to an advantageous pair of seals between a hard insulating plate and a high-insulation soft body plate. The abutting surface of the hard insulating plate slightly compresses the abutting surface of the high-insulation soft-body panel, as a result of which the abutting surface of the hard insulating plate acts as a sealing edge.

Claims 11 to 13 relate to thermal insulation boards with cavities. These thermal insulation boards make it possible to accommodate fibrous, well-insulating materials in the cavities. Furthermore, the cavities are also suitable for holding any highly insulating insulating materials. In particular, the design according to claims 12 and 13 allows easy filling of the cavities with the insulating material. The insulating plates are designed in two parts, one insulating plate part forming a bowl-shaped hollow shell, while the other insulating plate part forms a cover-like covering shell. The cover shell can be placed on the hollow shell like a pot lid on a pot. When the cover shell is attached, the cavity is completely hermetically sealed off from the surroundings. Since, in extreme cases, excessively large cavities could lead to the insulating plate becoming unstable, claim 13 proposes to incorporate several separate cavities into the insulating plate. In addition, such separate cavities can also be filled with different insulating materials. This is useful if parts of the insulating plate have to be particularly well insulated, while other parts have less insulation. The insulation can thus be variably adapted to the respective requirements.

Claims 14 and 15 relate to through openings for lines. Such lines can, for example, for the introduction of radiator rods, temperature sensors or the like. serve. Here, the inner surfaces of the passage openings are made of fiber-free material analogous to the bowl edges forming the outer walls of the cavities. The insulating plates are therefore completely fiber-free not only with respect to their outer sides but also with respect to the inner sides of the passage openings and are therefore reliable. In the final assembly state, the cross-sections of the through openings which are not filled by the lines are sealed with flange-like sealing plates. For this purpose, the sealing plates are expediently welded to the insulating plates in the final assembly state. It is also possible to provide the sealing plates with counter brackets in such a way that the flange-like sealing plates lie flat on all sides on the insulating material walls, so that no undesired thermal bridges occur at these points.

Fig. 1

eine Explosionsdarstellung des Schutzgehäuses und der Wärmeisolierschicht,

Fig. 2

eine schematische, geschnittene Seitenansicht des Elektro-Speicherheizgeräts,

Fig. 3

die schematische Darstellung wärmedicht aneinanderstoßender Isolierplatten.

Fig. 4

die Detaildarstellung des Stoßbereichs der Isolierplatten gemäß dem Kreis IV aus Fig. 3,

Fig. 5

den Stoßbereich zweier benachbarter Isolierplatten mit einliegendem Dichtstreifen,

Fig. 6

eine weitere Ausführungsform wärmedicht aneinanderstoßender Isolierplatten, teilweise mit Hohlräumen,

Fig. 7

die Detaildarstellung des Stoßbereichs gemäß Kreis VII aus Fig. 6,

Fig. 8

den Stoßbereich zweier Isolierplatten mit einliegenden Dichtstreifen.

The invention is explained in more detail with the aid of the drawings. Show it:

Fig. 1

an exploded view of the protective housing and the heat insulation layer,

Fig. 2

1 shows a schematic, sectional side view of the electrical storage heater,

Fig. 3

the schematic representation of heat-tight abutting insulating plates.

Fig. 4

the detailed representation of the joint area of the insulating plates according to the circle IV of Fig. 3,

Fig. 5

the joint area of two adjacent insulating plates with an inserted sealing strip,

Fig. 6

another embodiment of heat-tight abutting insulating plates, some with cavities,

Fig. 7

the detailed representation of the impact area according to circle VII of FIG. 6,

Fig. 8

the joint area of two insulating plates with inserted sealing strips.

The electric storage heater essentially consists of the protective housing, the heat storage core and the thermal insulation layer arranged between them. The protective housing is formed from the side parts 1, 1 ', the housing rear wall 2, the housing base 3, the housing cover 4 and the housing front wall, not shown in FIG. 1. The hard insulating plates 5 are firmly connected to the side parts 1, 1 '. The insulation in the area of the housing cover 4 is realized by the hard insulating plate 5, while the high-insulation soft-body plate 6 is arranged in the area of the housing base 3. The spacer 7 is also arranged between the high-insulation soft-body panel 6 and the housing base 3, the spacer 7 being designed as an air outlet grill in the region of the front wall, which is not shown in FIG.

The protective housing 8 assembled in FIG. 2 again has, according to FIG. 2, the housing rear wall 2, the housing cover 4, the housing base 3 and the housing front wall 9, not shown in FIG. 1. FIG. 2 further shows the hard insulating plate 5 that insulates the housing front wall 9 from the heat storage core 10. Like the housing front wall 9, the housing rear wall 2 and FIG Housing cover 4 each isolated from the environment by means of a hard insulating plate 5. The housing base 3 is insulated from the heat storage core 10 by means of the high-insulation soft-body plate 6. Additional high-insulation soft-body panels 6 are also provided in the area of the housing cover 4 and the rear wall 2 of the housing.

Both between the rear wall 2 and the associated high-insulation soft-body panel 6 and between the housing base 3 and the associated high-insulation soft-body panel 6, an installation space 11 is kept free for additional components. In the area of the rear wall 2, the installation space 11 serves as a switch room.

FIG. 3 shows an embodiment with a vermiculite insulating plate 12 and three silicon oxide insulating plates 13. The drawing plane of FIG. 3 is spanned by the vertical direction 14 and the horizontal direction 15. Two of the silicon oxide insulating plates 13 run according to their cross section in FIG. 3 in the vertical direction 14 and thus correspond to the insulating plates in the area of the housing side parts 1, 1 '. The vermiculite insulating plate 12 is arranged in the horizontal direction 15. The third silicon oxide insulating plate 13 resting on the vermiculite insulating plate 12 likewise runs in the horizontal direction 15. The vermiculite insulating plate 12 and the silicon oxide insulating plate 13 resting thereon correspond to the housing cover 4 according to the illustration in FIG. 3. The seal between the insulating plates 12 , 13 is shown on the basis of the butt joint area in the upper left corner according to the circle IV in FIG. 4. The silicon oxide insulating plates 13, which are made of microporous silicon oxide, are encased with a quartz or glass fiber fabric for protection. The silicon oxide insulating plate 13 running in the vertical direction 14 in FIG. 4 has the bulge 16 in its abutting surface area. The bulge 16 is complementary to the cranked abutting surface 17 of the vermiculite insulating plate 12 extending in the horizontal direction 15. The bulge 16 in the abutting area of the silicon oxide insulating plate 13 in FIG. 4 forms over the plane of the drawing spanned by the vertical direction 14 and the horizontal direction 15 standing cross section of the joint area of the silicon oxide insulating plate 13, a receiving groove for the vermiculite insulating plate 12 arranged in the horizontal direction 15. The vermiculite insulating plate 12 fits exactly in the manner of a cover into the space between the two silicon oxide insulating plates 13 running in the vertical direction 14 In terms of its weight, the vermiculite insulating plate 12 lies with its two cranked abutting surfaces 17 in the bulges 16 of the silicon oxide insulating plates 13 arranged in the vertical direction 14. The third silicon oxide insulation plate 13, which rests on the vermiculite insulation plate 12 in the horizontal direction 15, serves to weigh down the vermiculite insulation plate 12 and as additional insulation.

5 shows the joint area of a hard insulating plate 5 running in the vertical direction 14 with a vermiculite insulating plate 12 running in the horizontal direction 15, the vermiculite insulating plate 12 in turn being weighted down by a silicon oxide insulating plate 13 likewise running in the horizontal direction 15. Both the abutting surface 17 of the vermiculite insulating plate 12 and the hard insulating plate abutting surface 18 are made flat according to the exemplary embodiment in FIG. 5. 5, the sealing strip 19 is inserted between the abutting surface 17 of the vermiculite insulating plate 12 and the hard insulating plate abutting surface 18. The sealing strip 19 is made either of quartz silk fabric or high-melting glass silk fabric. 5 shows the embodiment of a flattened fabric hose as a sealing strip 19.

The left part of FIG. 6 shows a vermiculite insulating plate 12 running in the vertical direction 14. The vermiculite insulating plate 12 has bulges 16 which are double angled at their abutting regions 20. These bulges 16 in turn form a receiving channel for the silicon oxide insulating plates 13 arranged in the horizontal direction 15. The silicon oxide insulating plates 13 arranged in the horizontal direction 15 likewise have double-angled abutting surfaces 17 in the abutting regions 20. The vermiculite insulating plates 12 and the silicon oxide insulating plates 13 are thus designed in the joint areas in the manner of a matrix and a matrix. In the final assembly state, a bulge 16 and an abutting surface 17 each form a wide-sealing, form-fitting surface seal.

The right half of Fig. 6 shows another embodiment according to the invention. The vermiculite insulating plate 12 arranged in the vertical direction 14 is made in two parts according to the right half of FIG. 6 and consists of the bowl-shaped hollow shell 21 and the cover shell 22 placed on the bowl-shaped hollow shell. The cavities 23 are introduced into the hollow shell 21. The cavities 23 serve for recording Highly insulating materials, for example pebble, perlite, expanded clay or expanded slate etc. For this purpose, the cavities 23 are filled with the insulating material before assembly and then the cover shell 22 is placed on the hollow shell 21 and firmly connected to it. In this way, the cavities 23 are hermetically cut off from the ambient air.

Furthermore, the passage opening 24 for the line part 25 is shown in FIG. 6. The passage opening 24 breaks through both the cover shell 22 and the hollow shell 21. The outer walls 26 forming the bowl edges of the bowl-shaped hollow shell 21 form the inner surfaces 27 of the passage opening 24. The cavities 23 are thus also completely insulated from the passage opening 24.

The line part 25 can be introduced into the passage opening 24. The line part 25 carries the flange-shaped sealing body 28 on its side facing the storage core 10 in the final assembly state. In the final assembly state, the flange-shaped sealing body 28 is located in the flange groove 29 introduced on the storage core side on the through opening 24.

The right-hand half of the vertically arranged, two-part vermiculite insulating plate 12 according to FIG. 6 and the silicon oxide insulating plate 13 arranged in the horizontal direction 15 is shown in FIG. 7. The abutting surface 17 of the silicon oxide insulating plate 13 arranged in the horizontal direction 15 is flattened according to FIG. 7. Corresponding to this flattening 17, the insulating lug 30 projects from the covering shell 22 into the gusset 31 formed by the abutting surface 17 of the silicon oxide insulating plate 13 and the outer wall 26 of the hollow shell 21. The insulating nose 30 snaps into the gusset 31, so to speak, according to the lock-key principle.

FIG. 8 shows an embodiment that differs from FIG. 7. The insulating nose 30 according to FIG. 8 is a projection which only projects beyond the outer wall 26. The insulating effect is achieved in this embodiment by the sealing strip 19. The sealing strip 19 is positioned between the outside of the outer wall 26 of the hollow shell 21 and the side surface of the silicon oxide insulating plate 13 arranged in the horizontal direction 15 facing the hollow shell 21. The sealing strip 19 from FIG. 8 otherwise corresponds to the sealing strip 19 from FIG. 5.

Reference list

1.1 '

Side panel

2nd

Rear panel

3rd

Case back

4th

Housing cover

5

Hard insulating plate

6

High-insulation soft body panel

7

Spacers

8th

Protective housing

9

Front wall of the housing

10th

Heat storage core

11

Installation space

12th

Vermiculite insulating plate

13

Silicon oxide insulating plate

14

Vertical direction

15

Horizontal direction

16

bulge

17th

Butt surface

18th

Hard insulating plate joint surface

19th

Sealing strips

20th

Joint area

21

Hollow shell

22

Cover

23

cavity

24th

Passage opening

25th

Line part

26

Outer wall

27

Inner surface

28

Sealing body

29

Flange groove

30th

Insulating nose

31

gore

Claims (15)

1. An electric storage heater

   a) with a heat storage core (10),

   b) with a protective casing (8) substantially surrounding the storage core (10) and

   c) with a heat insulating layer

   c1) thermally insulating the storage core (10),

   c2) arranged between the storage core (10) and the protective casing (8),

      characterized in that

   d) the heat insulating layer consists of several insulating slabs (5,6,12,13),

   e) the surfaces of the insulating slabs which are in contact with the air flow of the air to be heated, consist of a nonfibrous material and

   f) in the final assembled state, the insulating slabs form with their abutting faces (17) a thermally leakproof areal contact.
2. A storage according to claim 1,
      characterized in that
   the abutting faces (17) of the insulating slabs (5,6,12,13) are in their cross-sectional shape adapted to each other in the manner of a bottom die and top die in such a way that in their final assembled state, they engage in each other with a form-fit for the heat-tight connection of insulating slabs (5,6,12,13) adjoining each other in the zone of the abutting faces (17).
3. A storage heater according to claim 2,
      characterized in that
   between the abutting faces (17) of two adjoining insulating slabs (5,6,12,13), there is inserted a deformable sealing means for improving the seal of the gap.
4. A storage heater according to claim 3,
      characterized in that
   the sealing means is a plastically deformable slab of a soft material
5. A storage heater according to claim 3,
      characterized in that
   the sealing means is an elastically deformable inorganic fibre fabric with a fibre thickness of more than 5µm.
6. A storage heater according to claim 3,
      characterized in that
   the fibre fabric is a tubular fabric.
7. A storage heater according to one or more of the preceding claims,
      characterized in that
   the insulating slabs (5, 6, 12, 13) are designed as hard insulating slabs (5) and preferably consist of inorganically bound vermiculite.
8. A storage heater according to one or more of the preceding claims,
      characterized in that
   the insulating slabs (5, 6, 12, 13) are designed as highly insulating slabs (6) of a soft substance and preferably consist of microporous silicon oxide.
9. A storage heater according to one or more of the preceding claims,
      characterized in that
   the insulating layer consists partly of hard insulating slabs (5) and partly of highly insulating soft substance slabs (6).
10. A storage heater according to claim 9,
       characterized in that
    in the final assembled state, the abutting faces (17) of the hard insulating slabs (5) closely fit against the abutting faces of the highly insulating soft substance slabs (6) in such a way that for sealing the gap, the abutting faces (17) of the highly insulating soft substance slabs (6) are compressed by the areal pressure of the abutting faces (17) of the hard insulating slabs (5).
11. A storage heater according to one or more of the preceding claims,
       characterized in that

    - hollow spaces (23) are introduced into the insulating slabs (5, 6, 12, 13) and

    - that the hollow spaces (23) can be filled in with a highly nonconductive insulating material.
12. A storage heater according to claim 11,
       characterized in that
    the insulating slabs (5, 6, 12, 13) can be assembled from a dish-shaped hollow shell (21) for taking up the insulating material and a lid-type cover shell (22) that can be placed on the hollow shell (21).
13. A storage heater according to claim 11 and/or claim 12,
       characterized in that
    the insulating slab (5, 6, 12, 13) has several hollow spaces (23).
14. A storage heater according to claim 13,
       characterized in that
    several passage openings (24) for lines (25) are introduced into the cover shell (22) and that the outer walls (26) of the hollow spaces (23) forming the dish edges form the inner surface (27) of the passage openings (24) in the hollow shells (21).
15. A storage heater according to claim 14,
       characterized in that
    the lines (25) are provided with flange-type sealing bodies (28) for an insulating seal of the passage openings (24) in the final assembled state.

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