DE1501506A1 - Heat pipes - Google Patents

Description

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Berlin, May 20th EUROPEAN ATOMIC COMMUNITY (EURATOM) Patent «and Gm auxiliary registration

"Heat pipe"

When operating heat pipes, the sufficient supply of the evaporation space with condensate is a decisive factor Importance to. If the supply tears off for any reason, the tube will be inoperable, if not even destroyed.

_{αο The main source of} danger in this regard lies in the bis

C £> The usual type of condensate return to the evaporator

ω fungsrauBi. The condensate always comes from the edge »

^ zone of the evaporation space into the evaporation space,

{.. and it then essentially depends on the pressure in this room,

whether the (from the outside) heated surface of the evaporation room

fully moistened with condensate or not. Above

a certain heating output or, what is synonymous with it, beyond a certain length of the evaporation space, a condensate supply extending to the bottom of the tube can be used cannot be guaranteed. The remote evaporator walls therefore dry out.

The limitation of the heating power or * the evaporation space length at first glance, it seems to exclude small values, that heat pipes can be used as heat extraction elements for nuclear fuel elements. Because as a result The circumstances described cannot allow the released heat of fission over the entire length of the fuel element be removed.

The invention is based on the idea of solving the problem at hand by separating the evaporation zone from the condensation zone to solve «In practice this means that the condensate flowing into the pre-steaming chamber is removed from the heated Evaporator area kept away, but then the entire evaporator area is fed evenly «

The solution consists of the invention - in a first embodiment «- in the fact that the steaming drama from within is heated, and the backflowing condensate initially behind a separating the evaporation chamber and the heater, for the condensate permeable wall is passed. In the above mentioned. Combination of a heat tube with a nuclear fuel element so is the stoker al »? acheialsynunetric in nuclear fuel rod built into the evaporation chamber, and the permeable wall designed as a concentric, porous tube »This embodiment already has a core

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1 t> ΓΊ "1 CZ ft £ fuel rod simulating electric heater successfully Tried and tested “In this way, rod lengths of up to several meters can be cooled by heat pipes, especially in weightless conditions Space · According to a second embodiment of the invention becomes the separation of the evaporation and the condensate inflow zone achieved according to the invention in that the evaporation space Heated inside and partly also in the condensation room is cooled on all sides or on one side and the refluxing condensate in the evaporation chamber from the unheated is passed to the heated wall through a corresponding wetting structure. The wetting structure leaves a steam room inside; However, it covers the outside all wall parts of the pre-steam room - the heated Surfaces as well as the unheated ones.

Details of the specified solutions as well as the mode of action the corresponding heat pipe. wcrdsn now on the basis of Drawing described in more detail; os shows

Fig, l a centrally through a nuclear fuel rod in the Evaporation raura heated heat pipe in the vertical cut,

2 a heat pipe heated on one side by nuts, schematically in longitudinal section, and

Fig.3 one centrally through a nuclear fuel rod

heated heat pipe unit with several evaporation chambers, cut perpendicular to the longitudinal axis.

In Fig-1, 1 denotes the heat pipes, 2 the heater, 3 one kondonsatdurc nleasigon pipe mesh, ^ t a gas-tight pipe

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attachment, 5 a condensate reflux structure (capillary structure), 6 a water cooler, 7, 8 its inlet and outlet lines, 9 a sealing sleeve, 10 the associated screw plug and 11 the corresponding sealing ring. The unit is designed for use in a vertical position. A multitude such elements can be combined to form a reactor rod grid will. The heater 2 would then, as indicated, be a nuclear fuel Rod.

The part of the heat pipe surrounded by the water cooler 6 forms the condensation zone of the same that receives the heater 2 Part forms the evaporation zone of the tube. The heat carrier, in the case of a nuclear fuel element as a heater, a melting and vaporizable metal, is not shown in Fig. 1! When the heat pipe is switched off, the heat transfer medium is in the collecting space 12, from which it is when it is started up the tube is evaporated by an auxiliary heater in the heater tube. During operation, the heat transfer medium circulates in a two-phase manner Circulating flow - ascending in vapor form in the tube axis, liquid flowing down the tube wall - back and forth between the evaporator and condensation zone * The actual one The evaporation space of the pipe is the annular space 13 between the heater 2 and the condensate-permeable pipe ineatz 3

The outer annular space Ik is designed to form a condensate reservoir, because according to the invention the separation of the evaporation zone from the condensate inflow zone is to be achieved by heating the evaporation space, here annular space 13, from the inside, namely by the heater 2 , and that the back-flowing condensate is initially behind a wall that separates the steam space and the heater and is permeable to the condensate, namely the pipe insert 3 - that is

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into the reservoir Ik - is passed. In this way it is prevented that the back-flowing condensate is not already heated so strongly when it enters the evaporator zone that it evaporates before it reaches the bottom of the pine tree. Another advantage of a reservoir is that the evaporator surface from it - it is the inner surface of the permeable pipe insert 3 - is always uniformly exposed to condensate at all points. This and the central arrangement of the heater now allow the conversion of all the heat given off by the heater into pre-steaming work without being restricted by the heater length »

The purpose of the pipe attachment k on the insert 3 is to pressurize the condensate reservoir into the condensation zone in order to utilize the vapor pressure drop between the evaporation zone and the condensation zone as fully as possible for supplying the evaporator surface with condensate. At grb'sseron Transportlängen it must be designed to insulate against flukes. »The condensate return structure 5, which is still present - it consists of a large number of axially parallel filaments, acts as a capillary structure. Sis favors the condensate backflow.

Fig. 2 shows the second embodiment of the invention as shown by the arrows f or f on the evaporator or on the condensation zone the heat pipe 15 is indicated, the separation of the evaporation and condensation flow zone is thereby achieved achieves that the evaporation space is heated on one side, the condensation space on one side on the opposite side is cooled, and that further condonsate flowing back, see the arrows f_, in the evaporation chamber from the unheated to the

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heated wall through a corresponding wetting structure is routed · The appointment structure consists of a stack Ringegraento layered at right angles to the tube axis with spacing in between 16 with spacer lugs on the side and below

In the present case, the ring segments are on those of the heating zone (dashed box) the opposite zone is kept narrower, so that it covers the entire segment package seen, again the condensate collection space with the one above mentioned function arises. In the drawing, the condensate level is illustrated by dashed lines 17. The distance between the ring segments is dimensioned so that the spaces between them have a capillary effect. The entirety of the ring openings form the vapor space of the tube; see the arrows fj ,.

In the middle and upper part of the heat pipe there is again the gas-tight pipe already discussed in connection with Fig. 1 * attachment 18 and the condensate reflux structure I9. Furthermore FIG. 2 shows the solution principle of the second embodiment of the invention only schematically. A practical execution FIG. 3 shows the case where several evaporation spaces are heated by a nuclear fuel rod.

In Fig, 3, the nuclear fuel rod 20 is in a sheath 21 with four radial ribs 22 introduced. The ribs share what is created by the outer jacket tube 23 - the actual heat pipe Annular space into four subspaces. Each sub-space forms

det an independent evaporation room.

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The construction combines in a peculiar way the two solution principles proposed according to the invention · For all of the pre-steam rooms are centrally heated

geraHss Pig 1 is available for the individual evaporation room one-sided heating according to Fig. 2 before. The combination of both principles results in an optimization in the question of warmth the use of space and space. It can also be the volume ratio of fissile to non-fissile material be dimensioned so that even for the application of the element in fast reactors criticality is sufficient Reactivity reserve is reached.

In the Dampfräumo 24, similar to the case of FIG. 2, stacks of ringsegmeii + pn 25 with spacer lugs are inserted laterally and below. Again, the distances Bd are dimensioned so that the Sogmente in the horizontal capillary u * · *> « uii ^^ n. At the vertical, they leave a wider gap on the cladding tube 23 than on the fuel rod, so that the condensate space mentioned repeatedly is created again.

The totality of the segment openings is central to the respective one Steam room. Typical of this type of denotation structure is therefore that they rush to the outside wall parts of the evaporation room ~ the heated tone as well as the unbehoizton covered and forms the vapor space inside.

Instead of the segment stack, a single condensate-permeable Body can be used, e.g. a double-walled

ger porous tubular body with radial partitions (in section co

° like the profile picture of the covers 21 and 23 taken together), co

- ^ In order to have as dense a packing as possible with elements according to FIG

in a roaktor bar grid, the participating

** "ton components of the Elßmentes, but at least the shell 23, expediently prismatic, τ ,, Β, hexagonal, formed.

Furthermore, for the purpose of temperature equalization along the Fuel rod, the heat tube must be provided in layers (i.e. cut-off) with radial partition walls * each section then works as a separate WärmerÖhrθ, whereby zone by zone the effect of temperature constancy during evaporation and condensation is harnessed.

The invention includes everything that contained in the description or is or illustrated in the drawings, one finally of what deviation is close on the concrete from management s at play en for the expert "

Claims t

HB / Hi - 16 965/66

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Claims (1)

PATENT CLAIMS 1 »J Wärmeröhrο, characterized in that the evaporation chamber (13) is heated from the inside and the backflow Condensate first behind a, the evaporation sr aunt (13) and the heater (2) separating, permeable to the condensate Wall (3) is directed. (Fig.l) 2 · heat pipe, characterized in that the pre-steaming space heated on one side and expediently also the condens actions r is now cooled on one side or on all sides, and that backflowing condensate in the evaporation chamber from the unheated to the heated wall through a corresponding Wetting structure (16) is passed, (Fig. 2) 3. Heat pipe according to claim 1, characterized in that a nuclear fuel rod is axially symmetrical as a heater the evaporation space is built in, and a concentric porous tube serves as a permeable wall » k * Heat pipe according to claim 2, characterized in that the wetting structure on the outside covers all wall parts of the evaporation space - the heated as well as the unheated -, but leaves a vapor space free on the inside. 5 · WHrmer tube according to claim (i, characterized in that the wetting structure is designed as a double-walled porous tubular body with radial partitions. 909836/0544 6 · Heat pipe according to claim 4, characterized in that the wetting structure from a stack at right angles to the pipe axis with spaced-apart stratified segments with openings that in their entirety form the vapor space. 7. li & rmeröhre according to claims 2 and k, characterized in that several evaporation rooms with Donetzee structures are arranged around a central heater 8, heat pipe unit according to claim 7j characterized from a ring of heat pipes around a central core burner * fabric rod. 9 * fiirm tube according to claims 1 or 2, characterized in that that the permeable wall or the wetting structure up to the condensation space by a gas-tight Wall, 3.B «a pipe socket, is extended. BAD ORIGINAL 909836/0544 Blank page