DE102011014194B4 - Food temperature control and storage insert, transportable temperature control and storage device as well as process for the production of a temperature control and storage insert - Google Patents

Abstract

Food temperature control and storage insert (40), which comprises a closed housing (41) and a latent heat accumulator (61) which can be repeatedly charged therein,
- The latent heat store (61) at least 80% of the interior (48) of the housing (41) at room temperature,
the latent heat store (61) comprises a material that is solid at a temperature of 60 degrees Celsius and that is liquid at a temperature of 95 degrees Celsius,
- wherein the housing (41) comprises at least one rigid housing flange (47),
- At least at room temperature, the internal pressure in the housing (41) is between 0.1 bar and 0.5 bar and
- The housing (41) comprises an elastically deformable, concavely curved cover (51).

Description

The invention relates to a food temperature control and storage insert, which comprises a closed housing and a latent heat storage device which can be repeatedly charged therein, a temperature control and storage device with such an insert, and a method for producing a temperature control and storage insert.

From the DE 101 07 922 A1 a latent heat storage is known, which is attached to the underside of a plate with a cover. The latent heat storage heats up to 50 - 55 degrees during operation and emits heat for about half an hour.

The DE 199 32 872 A1 teaches to heat a storage chamber with a latent heat storage to 130 degrees and then to place it in a heat-insulating outer container. Here, the storage chamber can deform or burst due to the already large volume of the solid latent heat storage. This affects the insertion in the outer container and the heat transfer to the food.

The present invention is therefore based on the problem of developing a food temperature control and storage insert, a temperature control and storage device with such an insert, and a method for producing a temperature control and storage insert, which heat and keep the food warm over a long time interval enables.

This problem is solved with the features of the main claim. For this purpose, the latent heat store fills the interior of the housing at least 80% at room temperature. The latent heat storage comprises a material that is solid at a temperature of 60 degrees Celsius and that is liquid at a temperature of 95 degrees Celsius. In addition, the housing comprises at least one rigid housing flange. At least at room temperature, the internal pressure in the housing is between 0.1 bar and 0.5 bar. The housing includes an elastically deformable, concavely curved lid.

• 1: Dimetrische Ansicht einer Temperier- und Lagervorrichtung;
• 2: Teilschnitt einer Vorrichtung nach 1.

Further details of the invention emerge from the subclaims and the following description of schematically illustrated embodiments.

• 1 : Dimetric view of a temperature control and storage device;
• 2nd : Partial section of a device 1 .

The 1 shows a dimetric view of a transportable temperature control and storage device ( 10 ). Such devices ( 10 ) are used, for example, to distribute food in hospitals. The transportable temperature control and storage device ( 10 ) includes, for example, a receiving part ( 20 ) and one in the receiving part ( 20 ) used temperature control and storage insert ( 40 ). If necessary, the temperature control and storage device ( 10 ) one on the receiving part ( 20 ) attachable protective and warming covers, not shown here. The recording part ( 20 ) and the protective and warming lid enclose this on the temperature control and storage insert ( 40 ) standing good, for example a warm menu to be served. The temperature control and storage device ( 10 ) circular with a center line normal to the base ( 15 ) educated. The outside diameter is, for example, 280 millimeters.

The 2nd shows a partial section of the temperature control and storage device ( 10 ). The double-walled receiving part ( 20 ) is bowl-shaped. Its outer wall ( 21st ) includes a tapered section surface that fits into a handle flange ( 22 ) transforms. The bottom ( 23 ) has, for example, a circumferential base ( 24th ). The height of the receiving part ( 20 ) is, for example, 60 millimeters.

The inner wall ( 25th ) is spaced from the outer wall ( 21st ) arranged. It overlaps the upper edge of the outer wall ( 21st ) and is with it for example in the handle flange ( 22 ) welded. The two parts ( 21st , 25th ) can also be glued, pressed, etc. together. The one with a thermally insulating material ( 27 ), e.g. a polyurethane foam, filled interior ( 26 ) is completely from the environment ( 1 ) Cut.

Above the handle flange ( 22 ) has the inner wall ( 25th ) a centering ring ( 28 ). The protective and warming lid is centered on this, for example.

The floor area ( 29 ) the largely flat inner wall ( 25th ) has an embossed all-round bottom ring ( 31 ). For example, it has a constant depth of 1.5 millimeters.

The cone-shaped inner surface ( 32 ) has a paragraph ( 33 ) which has a circumferential ring surface ( 33 ) forms. This ring surface ( 33 ) is parallel to the floor surface, for example ( 29 ) and is at a distance of e.g. 30% of the height of the receiving part ( 20 ).

Both the outer wall ( 21st ) as well as the inner wall ( 25th ) are made in the exemplary embodiment from a thermosetting or thermoplastic material, for example by means of a casting process and optionally by means of a forming process. The material is, for example, an impact-resistant polypropylene, for example PPN.

The temperature control and storage use ( 40 ) includes a housing ( 41 ), in which an energy store ( 61 ) thermal energy is arranged. The housing ( 41 ) consists of a bottom part ( 42 ) and from a lid ( 51 ). Its diameter is in the embodiment 220 Millimeters, its height, for example, a tenth of this diameter. Both the bottom part ( 42 ) as well as the lid ( 51 ) are made, for example, by injection molding from a thermoplastic, eg polypropylene filled with 20% talc. The material is, for example, food safe.

The pot-shaped bottom part ( 42 ) has a constant wall thickness of 1.5 millimeters in the exemplary embodiment. The floor area ( 43 ) has, for example, four feet that are designed in the shape of a circle ( 44 ), which are arranged on a common pitch circle. The diameter of this pitch circle corresponds, for example, to the diameter of the middle circle of the base ring ( 31 ). Central on the inside of the floor ( 45 ) is the injection point of the base part ( 42 ).

The frustoconical wall surface ( 46 ) - their slope corresponds to the slope of the lower section of the inner surface ( 32 ) - ends at the bottom ( 45 ) opposite end in an annular support flange ( 47 ). In the assembled state, this support flange ( 47 ) on the ring surface ( 33 ) on.

The lid ( 51 ) has the same outer diameter as the base part when assembled ( 42 ). The concave top ( 52 ) has a radius of curvature of 5300 millimeters, for example. This outside ( 52 ) has an all-round stamped cover ring ( 53 ), the depth of which is, for example, one millimeter. With this cover ring ( 53 ) can e.g. plates on the tempering and storage insert ( 40 ) be centered. The injection point ( 54 ) of the lid ( 51 ) is located, for example, centrally on the inside ( 55 ) of the lid ( 51 ).

Inside ( 48 ) of the housing ( 41 ) is an energy store ( 61 ) stored thermal energy. This is a latent heat storage ( 61 ), which is solid at a temperature of 60 degrees Celsius and liquid at a temperature of 95 degrees Celsius. The material of the latent heat storage ( 61 ) includes, for example, a paraffin-based material, for example it has a paraffin core. The latent heat storage ( 61 ) is a pressed part in the exemplary embodiment, the molecular chains of the saturated hydrocarbons as the mean value, for example, between 35 and 45 Have carbon atoms. The molecular lengths can be distributed, for example, according to a Gaussian bell curve. But it is also conceivable that all molecular chains have the same length. Other distributions of chain lengths are also conceivable. If necessary, the wax compact can comprise nucleating agents to promote crystallization and / or graphite fractions to increase the thermal conductivity.

The volume of the truncated cone-shaped latent heat storage ( 61 ) is greater than 430000 cubic millimeters in the exemplary embodiment. Its height is less than 10% of its maximum length. In the exemplary embodiment, the height is 7% of the largest diameter of the latent heat store ( 61 ). At room temperature, for example 20 degrees Celsius, the material has, for example, a heat capacity between 2 and 2.9 kilojoules per kilogram and Kelvin. The melting range is between 65 degrees Celsius and 90 degrees Celsius. The phase change from the solid to the liquid state can take place at a melting point, for example at 80 degrees Celsius, or in an interval, for example between 75 degrees Celsius and 85 degrees Celsius. The interval can also include the melting range mentioned. The liquid material can solidify at a solidification temperature that is, for example, one degree Celsius cooler than the melting temperature. The solidification can also take place in the temperature intervals limited by the temperatures mentioned in connection with the melting.

The density of the solid material of the latent heat storage ( 61 ) is, for example, 15% higher than the density of the liquid material. Thus, the liquid material with the same mass has a volume that is higher than the solid material. The material is chemically inert and non-toxic. Instead of the organic materials described, inorganic latent heat stores, for example salt hydrates or mixtures, can also be used.

In the manufacture of the temperature control and storage insert ( 40 ) the latent heat storage that is solid at room temperature ( 61 ) in the bottom part ( 42 ) inserted. After putting on the lid ( 51 ) is in the interior ( 48 ) of the housing ( 41 ) by suction a negative pressure in relation to the environment ( 1 ) manufactured. After vacuuming, the pressure in the interior is ( 48 ) between 0.1 bar and 0.5 bar. In the exemplary embodiment, the internal pressure of the housing ( 41 ) reduced to 0.2 bar. The elastically deformable lid ( 51 ) and possibly the floor area ( 43 ) are directed towards the interior of the housing ( 48 ) drawn.

Along the seam ( 49 ) between the top of the support flange ( 47 ) and the lid ( 51 ) the housing ( 41 ) sealed gas-tight by welding with or without additional material, gluing or pressing, etc. The latent heat storage ( 61 ) now fills the interior of the housing ( 48 ) more than 80%. In the exemplary embodiment, the degree of filling is 90%. After joining the housing parts ( 42 , 51 ) the edge is outside the joint ( 49 ) turned and smoothed. If necessary, vacuuming and joining can be carried out in one operation. Another order of manufacture is also conceivable.

In series production, due to the machine-made latent heat storage ( 61 ) and the automatable housing production, temperature control and bearing inserts ( 40 ) are manufactured with a narrow spread of their geometric and thermal properties.

In order to operate the temperature control and storage device ( 10 ), at least the temperature control and storage use ( 40 ) warmed. For example, heating takes place in a water bath from room temperature to a temperature of 98 degrees Celsius. Heating in a forced air oven or other heating devices is also conceivable. The heating temperature is, for example, below 110 degrees Celsius. When heated, the latent heat accumulator ( 61 ) thermal energy. This thermal energy causes, among other things, an expansion of the latent heat storage ( 61 ). When the melting temperature or the melting temperature interval is reached, the energy supplied causes a phase change. There is no or only a slight increase in temperature of the latent heat storage ( 61 ). The energy absorbed by the latent heat storage for melting ( 61 ) is, for example, between 180 kilojoules per kilogram and 240 kilojoules per kilogram.

The latent heat storage ( 61 ) becomes fluid. Only after complete conversion does the temperature of the now liquid latent heat storage ( 61 ), whereby the volume of the latent heat storage ( 61 ) enlarged. The latent heat storage ( 61 ) now takes the entire interior, for example ( 48 ) of the housing ( 41 ), the gas in the interior ( 48 ) is compressed to atmospheric pressure, for example. If necessary, the lid ( 51 ) are elastically deformed in the direction of a plane. The floor area ( 43 ) can be on one level again. At least the housing flange ( 47 ) is rigid and is not deformed.

After inserting the temperature control and storage insert ( 40 ) into the receiving part, which is also heated, for example ( 20 ) the support flange ( 47 ) on the ring surface ( 33 ) on. Below the support flange ( 47 ) limit the temperature and storage use ( 40 ) and the receiving part ( 20 ) an air gap ( 35 ). The width of the air gap ( 35 ) is between one and three millimeters in the exemplary embodiment. If necessary, the feet ( 44 ) in the centering ring ( 28 ) immerse or touch it.

Now a plate with e.g. preheated food or food to be heated can be placed on the lid ( 51 ) and the protective and warming lid are put on.

During transport and until the food is removed, the temperature control and storage insert ( 40 ) thermal energy. The air gap ( 35 ) forms an additional insulation layer so that the one from the latent heat storage ( 61 ) thermal energy given off by the cover ( 51 ) is passed through to the plate and the food stored on it. The heat emission surface corresponds to the surface of the cover ( 51 ), due to the greater thickness of the latent heat storage ( 61 ) There is a higher heat emission in the central area than in the peripheral area.

When the heat is given off, the temperature of the latent heat storage 61 ) to the temperature of the solidification point or to the upper temperature limit of the solidification interval. When the latent heat storage device releases further energy ( 61 ) it largely maintains its temperature, but changes its phase state. The latent heat storage ( 61 ) stiffens. The solidification energy released during solidification corresponds to the melting enthalpy absorbed during heating. For example, due to the low height of the latent heat storage ( 61 ) there is a largely uniform solidification of the material.

As soon as the latent heat storage ( 61 ) is completely solidified, it cools down, for example, to a temperature of, for example, 60 degrees Celsius. This reduces its volume. For example, the housing ( 41 ) its original shape again. This may take 90 minutes.

The heat storage capacity of the energy storage ( 61 ) depends on its material and volume. The greater the heat storage capacity and the enthalpy of solidification, the longer the energy store ( 61 ) Give off heat.

The tempering and positioning device ( 10 ) for example on the handle flange ( 22 ) are touched.

After the food has been removed, the temperature control and positioning device ( 10 ) cleaned again. Here, for example, water with high temperature and possibly high pressure is used. The joint connections ( 34 , 49 ) are designed in such a way that no moisture gets into the receiving part ( 20 ) or in tempering and storage applications ( 40 ) entry.

At least the temperature control and storage use ( 40 ) is heated up again for the next use.

The temperature control and storage use ( 40 ) can be used repeatedly. For example, more than 10 ⁴ charges and discharges of the energy storage ( 61 ) conceivable.

Reference list

1

Surroundings

10th

Temperature control and storage device

15

Center line

20

Recording part

21

Outer wall

22

Handle flange

23

bottom

24th

Pedestal

25th

Inner wall

26

inner space

27

thermal insulating material

28

Centering ring

29

Floor area

31

Bottom ring

32

Inner surface

33

Heel, ring surface

34

Joint connection

35

gap

40

Temperature control and storage use

41

casing

42

Bottom part

43

Floor area

44

Feet

45

ground

46

Wall surface

47

Support flange, housing flange

48

inner space

49

Seam, joint

51

cover

52

Top, outside

53

Lid ring

54

Injection point

55

inside

61

Energy storage, latent heat storage

Claims (8)

Food temperature control and storage insert (40), which comprises a closed housing (41) and a latent heat accumulator (61) which can be repeatedly charged therein, - The latent heat store (61) at least 80% of the interior (48) of the housing (41) at room temperature, the latent heat store (61) comprises a material that is solid at a temperature of 60 degrees Celsius and that is liquid at a temperature of 95 degrees Celsius, - wherein the housing (41) comprises at least one rigid housing flange (47), - At least at room temperature, the internal pressure in the housing (41) is between 0.1 bar and 0.5 bar and - The housing (41) comprises an elastically deformable, concavely curved cover (51). Food temperature control and storage insert (40) after Claim 1 , characterized in that the housing (41) is closed gas-tight. Food temperature control and storage insert (40) after Claim 1 , characterized in that the housing (41) comprises a bottom part (42). Food temperature control and storage insert (40) after Claim 1 , characterized in that the latent heat accumulator (61) comprises a paraffin-based material. Transportable temperature control and storage device (10), which has a receiving part (20) and a temperature control and storage insert (40) Claim 1 comprises, characterized in that the receiving part (20) has an annular surface (33) on which a housing flange (47) of the temperature control and bearing insert (40) rests. Transportable temperature control and storage device (10) Claim 5 , characterized in that the maximum gap (35) between the receiving part (20) and the temperature control and bearing insert (40) is less than three millimeters. Transportable temperature control and storage device (10) Claim 5 , characterized in that the receiving part (20) is thermally insulated. Process for the production of a temperature control and storage insert (40) Claim 1 , characterized in that - a latent heat store (61) is inserted as a pressed part in a base part (42), - that a cover (51) is placed to form a housing (41), - that in the interior (48) of the housing (41 ) by suction a negative pressure in relation to the environment (1) is generated, which after vacuuming is between 0.1 bar and 0.5 bar, - that in this case at least the elastically deformable cover (51) is pulled in the direction of the housing interior (48) and - that the housing (41) along a seam (49) between the top of the support flange (47) and the cover (51) is closed gas-tight.

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