DE6753172U - THERMOGENERATOR - Google Patents

Description

P.A. 395 374-17.

SIEMENS AKTIENGESELLSCHAFT Erlangen, the

Wemer-von-Siemens-Str. 50

PLA 68/1463

Thermal generator

The fire concerns an animal generator with p- or n-conducting ^ iiermoeleaeiitsclienkel, which between part and cold about a thexaiscne insulation rigidly attached to one another heat exchangers are arranged.

- 1 - Soe / Bü

PLA 68 / H63

In general, many thermocouples are combined in thermogenerators in such a way that their hot or cold soldering points each • in a surface, namely the hot or cold side of the thermal

generator lie. Each thermocouple consists of a thermo • Element leg pair with one p- and η-conducting thermocouple leg each made of thermoelectrically effective material. With contact bridges made of electrically and thermally conductive material the thermocouple legs are connected so electrically on their hot and cold side that all thermocouple legs are electrically in series and thermally parallel. Both on the hot and on the cold side of the thermocouples is placed in: general * -'_ n heat exchanger, which is separated from the contact bridges by a layer of thermally conductive and electrically insulating material.

The thermal contact between the thermocouple legs and the heat exchangers must be extremely good because of the efficiency of the thermal generator depends on this, among other things.

There is a temperature gradient between the hot and cold sides of the thermal generator, the amount of which is in the direction of the leg axis is very large and also locally different. This results in thermal expansions in the direction of the leg axis, which are also locally different and can be very large. Because of these expansion forces, the local fixation of the thermocouple legs between the heat exchangers be mechanically very stable. Also must must be observed when installing the thermocouple legs,

- - 2 - Soe / Hü

ι ^{/ f}

PLA 68/1463

that manufacturing tolerances in the Schnkel length cannot be avoided.

To compensate for the thermal expansion and the F ^ rti = movement tolerances and for the stable, locally fixed installation of the thermocouple legs, it is known to use springs if necessary. exert an elastic force in the axial direction on the thermocouple legs via a pressure piece. The Heat exchanger as an abutment. The disadvantage here is that the heat conduction between the pressure contact Thermocouple legs and the heat exchangers is deteriorated. There is also the risk that the pressure contact fails and the thermocouple legs are destroyed by the thermal expansion forces. Based on this principle Thermal generators are therefore not operationally safe.

Since there is a temperature gradient along the thermocouple limb, it can be advantageous to use the thermocouple limb to build up the thermoelectric properties from segments of different, thermoelectrically effective material to take full advantage of the materials used. The material is to be selected in this way and the dimensions of the segments in this way to be determined in such a way that each segment is in the temperature range maximum thermoelectric effectiveness. You get thus a significant improvement in efficiency. To the already mentioned thermal expansion forces in the direction of the leg longitudinal axis, however, ntm in Contact points of the S egmen ^ p ^ er ^ Ihsrmo element leg

h 7 πι ^ i ι * y ν υ * ti ο i ζ ιέ

- 3 - Soe / Hü

PLA 68 / H63

thermal expansion forces perpendicular to the longitudinal axis of the leg, since different materials are connected there. When constructing a Theraaugtinerator with segmented thermocouple legs, compensation for these expansion forces must also be taken into account. In addition, the contacting of the ξ segments must have good electrical and thermal conductivity. It is known to solder the segments on opposite surfaces of fine tungsten discs. To compensate for the thermal expansion forces, several solder layers with different thermal expansion coefficients are provided between the tungsten disk and the segments, with the aid of which the thermal expansion coefficients of the segment | materials are converted into the expansion coefficient of the tungsten disk. The contact is technically very difficult to make and requires several operations. The contact is made even more difficult by the different melting points of the semiconductor materials used in the segments of the thermocouple leg, which result in different soldering temperatures on both sides of the tungsten disk.

The task of thermal generators of the type mentioned at the outset is to reduce the thermal expansion forces that occur in Leg longitudinal axis and with segmented thermocouple legs in the contact points of the segments perpendicular to the Leg longitudinal axis occur to compensate with simple means.

67531? 2

- 4 - Soe / Hü

PLA 68 / U63

According to the innovation, the object is achieved in that the contact bridge !! are attached to the hot and cold heat exchanger and that one electrical for each thermocouple limb and thermally conductive connecting piece is provided which has a flexible section and which is between the contact bridge the cold side and the end face of the thermocouple leg or between two segments of the thermocouple leg is attached.

The material of the connecting piece preferably conducts better electrically and thermally than the thermoelectrically effective materials of the thermocouple legs.

The connector can be attached to the thermocouple leg via a metal plate be attached. This metal plate can be made from Be silver.

The flexible section can be elastic and can be made from spring steel sheet or spring wire. The elastic Part of the piece can also be a spring washer.

The flexible section can be a silver braid.

The connecting piece preferably consists of two sections which are mechanically connected to one another. The cuts can be staked, screwed or crimped together.

6703172

- 5 - Soe / Hü

PLA 68/1463

Among other things, at the aeaerungsgeaäSeB The regenerator the contact bridge !! The thermocouple legs are connected to the heat exchangers, is a good local fixation of the thermocouple legs ensured. The thermal expansion forces in The lengthways direction of the legs are compensated for by means of the flexible or elastic connecting piece. There is one good heat conduction and good electrical conductivity ensured - with segmented thermocouple legs In particular, the segments cannot be damaged because the segment ends hang freely in the space. aside from that • Has no effect on the connecting piece with segregated thermocouple legs in the contact point perpendicular to the longitudinal axis of the leg, only the expansion force of one of the Sege duck. This is compensated for by the elasticity of the connector. Further special precautions in Segment contact * for compensation of the thermal expansion forces, Above all, several people are no longer interested necessary.

Particularly noteworthy is the possibility of building the connecting piece from two parts that are mechanically connected are. This enables a simple manufacturing process in which the mechanical connection of the Sections of the connecting piece only takes place after the sections with the segments of the thermocouple leg or metallurgically connected with the end face of the thermocouple leg and with the contact bridge on the cold side.

- 6 - Soe / Hü

PLA 68/1465

are bound. This manufacturing process offers great advantages, especially when building segmented thermocouple legs. The mechanical connection of the sections of the connecting pieces can be done before or after the Contact bridges have been attached to the heat exchangers are.

In the following the innovation according to the thermal generator with reference to FIGS. 1 to 20, in which various embodiments are illustrated, explained in more detail by way of example. The embodiments shown in the figures differ primarily in the type of connecting pieces that are between the end faces of thermocouple legs and the contact bridges on the cold side or, in the case of segmented thermocouple legs, none between the segments are arranged. Analog parts are therefore provided with the same reference symbols in all figures.

Fig. ^Λ shows the front view of a thermogenerator according to the innovation, the hot heat exchanger 1 and the cold heat exchanger 2 being shown in section. The p- and n-conductive thermocouple legs _5_ are each made up of two segments 4 and 5. If the thermal generator is designed for a hot-side temperature of approximately 1OC Z , the segments 4, which are directly exposed to the hot-side temperature, are made of a GeSi alloy. GeSi alloys have a maximum thermoelectric effectiveness of around 750 to

ν oui c:

- 7 - Soe / Hü

PLA 68/1463

105O ⁰ C. The materials used for the segments 5 of the cold side of the thermal generator can be PbTe or Bi ₂ Ti, / Sb ₂ Te. These materials have a maximum thermoelectric effectiveness at around 200 to 600 ^° C. or around 50 to 300 ^° C.

The segments 4 of the hot side are 6 £ via a contact bridge from electr. ch and thermally good conductive material connected jj

1 den. The material for the contact bridge 6 are metal |

Silicon alloys, such as ^{molybdenum-silicon; i} alloys are particularly suitable. The contact bridge 6 sits in a recess of the heat exchanger 1 and is rigidly attached there by means of a hardenable ceramic compound 7. For this purpose, hardenable ceramic materials can be used which are commercially available, for example, under the name "Thermostix 2000" or "Thermostix 3000". These materials are electrically insulating and thermally conductive. Instead of the type of attachment of a curable ceramic compound, Xeramikformstüeke can be provided with which the contact bridge 6 is held or the Xontaktbrücke 6 can be screwed to the hot heat exchanger 1. It is also possible to fasten the Kentakt bridge 6 in a sliding manner in a breakthrough in the hot heat exchanger 1. The breakthrough is lined with a ceramic compound into which the contact bridge is fitted. In this Pail, the hot contact bridge β is directly exposed to the action of the heat source.

_{aos / m}

68/1463

Side attachment for the contact bridge 6 are shown in the figures not shown.

On the cold side of the thermal generator is on the Segaente A silver plate 8, which is provided with terminal lugs 9, is placed as a contact piece. The silver plate 8 can be bent towards the edges of the thermocouple leg 3. This prevents the material of the thermocouple leg j> comes into contact with doping solder layers. Silver braids 10 are attached to the connection lugs 9, Via the one connection to neighboring Thermoeleaentschenkeln J. or a decrease in the generated electrical energy is possible. Between the silver plates 8 and the cold heat exchanger 2, which is provided with heat exchange flags is, a ceramic plate 11 metallized on both sides is arranged, which is connected to the cold heat exchanger 2 and with is soldered to the silver plates. The material of this ceramic plate 11 can be aluminum oxide or beryllium oxide be. Both materials are electrically insulating and thermally conductive. In addition to the dockside fastening shown here the thermocouple leg _3 is also an adhesive connection or a screw connection with the cold heat exchanger 2 is possible. The possibilities too are not shown in the figures.

The segments 4 and 5 of the thermocouple legs 3 are means of a connector J ^ electrically and thermally conductive |

PLA 68/1463

connected with each other. E3 is soldered to the end face of each segment 4 and 5, a silver plate 13 or welded on. Between the silver plates 13 is as flexible and elastic part of a resilient ear 14 attached, which is formed from spring steel sheet. Bs is on it to point out that due to the elasticity of the silver sheet, no compressive forces have to be applied to compensate for thermal expansion forces. The shape of the resilient Tube 14 can be seen from FIG. 2, in which a section along the line II-II of FIG. 1 is shown.

Since the L gaente 4 and 5 .Each The rmo element give Is 2 rigidly attached to a heat exchanger via the contact bridges 6 and 8, they can freely expand in the space between the segments 4 and 5 in and risk of breakage due to the thermal expansion in There is no longitudinal direction of the leg. The thermal expansion perpendicular to the longitudinal direction of the leg is absorbed for each segment 4 and 5 by the elasticity of the silver plates 13, so that the contact between the segments is also safe from interference. The cross-section of the spring plate can be chosen so that the electrical and thermal resistance of the connector 13 in the electrical and thermal current path is practically insignificant and the efficiency of the thermal generator is not influenced by the Segaentkontakt.

In i? Ig. 3 is a Ausfuhxxmgsfora shown ₅ in the

- 10 -

Soe / Hü

PLA 68 / U63

the ρ- and η- leading thermocouple legs J5 not segmented are. The thermocouple legs 3 are made, for example, from a GeSi alloy. The connector JK2 is between the contact pieces 8 of the cold side u.id the

speaking end faces of the thermocouple legs JS are used. With the end faces of the thermocouple legs J5 and silver plates 13 are soldered to the contact pieces 8. On the silver plates 13 is iron spring washer as an elastic section 15 soldered. The spring washer 15 is shown in FIG. 4 in shown in the top view. In a departure from FIG. 3, the spring washer 15 can also be applied directly to the filter plate 8 be soldered- Also in this embodiment with unsegmented thermocouple legs 3. the thermal Expansion in the longitudinal axis of the leg due to the flexible connection piece J_2 fully compensated. Sine damage of thermocouple legs 3, does not occur during operation and for the manufacturing tolerance in the outer leg length relatively wide limits can be allowed. The thermal contact between the cold heat exchanger 2 and the thermocouple legs ^ is also good, since with a corresponding cross section of the spring washer 15 for a low electrical and thermal resistance can be ensured.

In Fig. 5, spring plates 16 are provided as elastic sections of the connecting piece 1_2, which the silver plates 13 two segmented thermocouple legs J5 crossed

- 11 - * Soe / Hü

PLA 68/1463

associate. The Pederbleche 16 are in Pig. 6 in plan view shown.

In Pig. 7 is the elastic part of the connector _ ^ 2 also made from spring steel sheet which is bent to form an S-shaped part 17. In the designated embodiment is da-i connector 12. between unsegmented-n thermocouple give a _2, and the contact pieces 8 of the cold side arranged.

Pig. 8 shows a section along the line VIII-TIII of Pig. 7th

In Fig. 9 i "the flexible connector JJ2 between segments 4 and 5 of thermocouple legs 2 t placed. The elastic portion of the connecting member 1_2 is formed of spring wire. The spring wire is wound into a tubular part 18, the axis of this tubular part 18 perpendicular to the longitudinal axis of the thermocouple leg 2 lies.

FIG. 10 is a section along the line X-X of FIG. 9 with a top view of the »tubular part 18 of the Connector ^ 2 shown.

Fig. 11 shows a connector J_2 with a spiral spring

Soe / Hü

.J753172

PLA 68/1463

19 as an elastic section. The connecting pieces _1_2 s: again between de_t end faces of the thermocouple nand the contact pieces 8 of the cold side arranged.

In FIGS. 12 to 18, the dunnage pieces .12. Silver braids 21 provided. In this context, it is particularly important to point out the mechanically produced connection between SiIb braids 21 with one another or between the silver braids 2 and the silver plate 13 contacted on the thermocouple leg 2. This gives the possibility of separately soldering the cover plates 13 onto the end face of thermocouple legs 2 or on segments 4 and and then mechanically connecting the thermocouple leg to the contact bridge 8 or the Segaentkontaktierung. If necessary, this mechanical connection can only be established after the contact bridges have been attached to the heat exchangers 1 and 2.

In Figure 12 are those on segments 4 and 5 of Thermoelea schenkein 2 silver plates 13 soldered, the with conn flags 20 are provided in which silver braids 21 are soldered or squeezed.

In FIG. 13, pinch legs 22 are placed on the silver plates 13 of the connection piece V2 , in which the syllable braids 21 are soldered or notched to connect the segments 4 and 5. ^ »^,

317

- 15 - Sun «

PLA 68/1463

Fig. 14 shows a modification of the embodiment of Fig. 13, "The connector ± 2 is rebuilt from Quetschfüßen 22, in which a ^D ilberzopf mechanises 21 is fixed. In this embodiment, however, the cold heat exchanger is designed at the same time as a contact bridge for the electrically conductive connection of adjacent thermocouple legs 3 . The cold heat exchanger is made up of two parts 2a and 2b, with each of which a pinch foot 22 is connected in an electrically conductive manner. The two parts 2a and 2b of the heat exchanger are electrically insulated from one another by an electrically insulating layer 23. The particular advantage of this embodiment lies in the avoidance of the thermal resistance which is otherwise provided by the thermally conductive layer 11 and which prevents the degree of efficiency.

In Pig. 15 the silver braids 21 are soldered directly to the silver plates. In addition, in this execution form of the connector J_2, the silver plates 13 have an annular flange 24, with which excessive kinking of the segmented thermocouple leg j5 is prevented.

In the connection piece _1_2 of FIG. 16, by which the segments 4 and 5 of a segmented thermocouple leg 2 are connected, the silver braids 21 are also soldered to the silver plates 13 of the connection piece. The silver braids 21 of each connecting piece T2 are, however, notched together by means of a crimp sleeve 25.

-H- "Soe / Hü

PLA 68/1463

The connector J_2 of FIG. 17 differs from see Connector J_2 of Fig. 16 in that at each Silver plate 13 two silver braids 21 are attached. To the Contacting the segments 4 and 5, the silver braids are mechanically connected again by means of crimp sleeves 25. These Aijsführungform can be advantageous when silver braids small diameter should be used.

In Fig. "38 a Thennogenerator with a modified connecting piece ± 2. According to Fig." 5 is shown. In this case, the silver braid 21 is not soldered in one of the metal plates 13, but is screwed by means of a screw 26. The screw connection is shown in the sectional view of the connecting piece 22, which is shown in the case of the p-conducting thermocouple limb 3 .

? ig. 19 shows the view of a thermal generator according to the invention, in which the connecting piece J ^ is made from sheet silver. Silver sheet metal strips 27 are soldered onto the end faces of the thermocouple legs J5 ^{and the contact pieces 8.} The sheet silver strips 27 protrude beyond the lateral delimitation of the thermocouple legs 2 and are bent away from the contact pieces S and the thermocouple legs 3. The laterally protruding sheet silver strips 27 are connected to one another by two flanged seams 28. The shape of the silver sheet strips 27 and the position of the flanged seams 28

Soe / Hü

PLA 68/1463

can be seen from FIG. 20, in which a representation along the lines XX-XX of FIG. 19 is shown. The silver sheet 27 can be elastic.

20 figures

15 claims for protection

Soe / flü

Claims (15)

. 3S5 374-S. 7.63 ή PLA 68 / Η63 protection claims 1. Thermogenerator with ρ- or »η-conductive Tharmocouple legs, the heat exchangers between hot and cold, rigidly attached to one another via thermal insulation are arranged, characterized in that the contact bridges (6, 8) on the hot and cold Heat exchangers (2, 1) are attached and that for each thermocouple leg (.3) an electrical and thermally conductive connector (J_2) provided is, which has a flexible section and which between the contact bridge (8) of the cold side and the End face of the thermocouple leg or between two segments (4, 5) of the thermocouple leg attached is. 2. Thermogenera, gate according to claim 1, characterized in that that the material of the connector (J_2) is electrical and thermally better than the material of the thermocouple schenkeis 3. Thermal generator according to claim 1 or 2, characterized in that the connecting piece (JJ2) is attached to the thermocouple leg (3) via a metal plate (13). - 17 - Soe / Hü PLA 68 / U63 4. Thermogenerator according to claim 3 »characterized in that that the metal plate (13) is made of silver. 5. thermal generator according to any one of claims 1 to 4s characterized da2 the flexible section is elastic. 6 = Theraogenerator according to claim 5 »characterized in that the elastic part is made of spring steel sheet (16, 27) . 7. thermal generator according to claim 6, characterized in that that the elastic part consists of a resilient ear (14) is shaped. 8. 'Tfaermogenerator according to claim 5, characterized in that that the elastic section is made of spring wire (IS). 9. Thermogenerator according to claim 6, characterized in that that the elastic part is a spiral spring (19) .. 1Ö »thermal generator according to claim 5, characterized in that that the elastic section is a spring washer (15). 11. Thermal generator according to one of claims 1 to 4, characterized in that the flexible section is a silver braid (21). - 18 - Soe / Hü PLA 68/1463 12. Thermal generator according to one of claims 1 to 4 »6 and 11, characterized in that the connecting piece (22) from consists of two parts that are mechanically connected to each other. 13. Thermal generator according to claim 12, characterized in that .lie sections are notched together. 14. Thermogenerator according to claim 12, characterized in that that * ie sections are screwed together. 15. Thermal generator according to claim 12, characterized in that that the sections are crimped together. - 19 - Soe / Hü