EP0585430B1 - Externally heated, regenerative heating and refrigerating machine - Google Patents

Abstract

An externally heated, regenerative heating and refrigerating machine working according to the Vuilleumier cyclic process has a pressure-tight housing (1) with two linearly and coaxially movable pistons (2, 3) arranged therein that delimit together a warm working volume (5). One of the pistons (2) delimits in the housing (1) a hot working volume (7) externally supplied with heat (6) by means of a burner (22) and the other piston (3) delimits a cold working volume (7). All three variable working volumes (5, 6, 7) communicate with each other through intermediate regenerators and heat exchangers. A control gear (S) for the pistons (2, 3) is arranged in the housing (1). The housing (1) is designed as a tubular pressure vessel (1') with forward and return flow connecting branches (10 to 13) for two heat transfer circuits. All regenerators (8, 9) and heat exchangers (14, 15) are arranged within the pressure vessel (1'). A piston bushing (16) with overflow openings (17, 18, 19) that lead to the working volumes (5, 6, 7) is also arranged in the pressure vessel (1'). The heat exchanger (15) for one of the heat transfer media delimits the cold working volume (7) on the one side and on the other side it delimits a space (70) in which is arranged the control gear (S) that cooperates with the piston (2, 3).

Description

The invention relates to an externally heated, regenerative heating and cooling machine operating according to the Vuilleumier cycle process. Such a heating and cooling machine is known, for example, from EP-A-0 238 707.

Such heating and cooling machines have already been developed based on the Vuilleumier cycle, which has been known since 1918, and have among other things. the advantage that they can be operated with helium or hydrogen gas instead of environmentally harmful CFCs.

Regarding the Vuilleumier cycle process and its constructive implementation options, reference is made to DE-Z: gwf-gas / erd-gas 127 (1986) No. 5, pages 205-210.

In the "control gear" mentioned in the preamble of claim 1, however, it is not a gear that can be used to control the piston movements, but only springs between the piston and the housing, which together with the piston in the housing form an oscillatory system. This does not apply directly to a constructive embodiment of such a "Vuilleumier machine" (see also the above-mentioned literature reference), in which the cylinders for the pistons are offset by 90 ° and the pistons are positively coupled to one another by a crank mechanism, which is the same as that The generic term corresponding to the basic principle with linearly and coaxially movable pistons is considered disadvantageous in that all regenerators and heat exchangers are peripherally assigned to the actual machine, which requires correspondingly complex connection, sealing and insulation measures.

A generic heating and cooling machine is known from EP-A-0283707. It is an externally heated heating and cooling machine, with two linear and coaxial moving pistons arranged in a pressure-tight housing with flow and return connections. A working volume formed can be supplied with heat from the outside by means of a burner. A power control that intervenes in the movement process of the pistons is not provided. In addition, the comparatively complex device is complex to manufacture and assemble and thus only requires a great deal of time.

The invention is therefore based on the object to improve a machine of the generic type in such a way that such a machine including the necessary heat exchangers and regenerators in a compact design for the implementation of the advantageous Vuilleumier cycle can be created, which is nevertheless easy and simple to assemble and should offer the possibility to intervene in the movement process of the pistons with respect to a power control.

This object is achieved with a machine of the type mentioned according to the invention by the features stated in the characterizing part of patent claim 1 and of patent claim 18. Advantageous further developments result from the subclaims.

This design according to the invention not only has the advantage that all the elements required for carrying out the cycle are combined in a single tubular container in a very small space, but these elements can also all be inserted from an open side during manufacture or assembly, which can then only be closed in a suitable manner in a pressure-tight manner. In this tubular container, a further space for accommodating a control gearbox is accommodated at the same time, namely below the "cold side" of the machine, which has the advantage that all movable elements can be exchanged from this side in the event of a possible damage tubular container ago to make. As a consequence of this design according to the invention, the entire system carrying the operating gas is enclosed in the pressure vessel without any external conduit guides, which only has to be provided with connections for the two heat transfer medium circuits.

Advantageous configurations of such a machine consist in the following:
The two pistons are provided with piston rods, which together engage in the space additionally arranged on the cold side, in which currentable and elastic control elements for the piston movements are arranged, the piston rods engaging with their piston rod ends between two E-magnets which are spaced apart according to the maximum piston stroke and each piston rod end between two against the Walls of the room supported compression springs are arranged clamped, and furthermore the piston rod of the piston limiting the hot working volume passes through the piston rod designed as a tube of the other piston and the ends of the piston rod are provided with two-armed cross arms, each of which grips between e-magnets and compression springs. In addition to the fact that, due to this design, the movement of the pistons can be controlled in an elegant manner for the purpose of regulating the power of the machine, the compact design is also consistently adhered to and both piston rods are oriented towards the cold side of the machine, on which the common control gear is also located.

The heat exchanger delimiting the accommodation space for the control gear is concavely curved towards the piston, as seen from the outside, and the associated piston on the side of the cold working volume is curved accordingly. The heat exchanger, which is thus designed to be pressure-favorable due to the curvature, forms, as it were, a bell arching over the additional space, the shape of which also simultaneously forms a relatively large heat transfer surface, which is cheap in that there are no large temperature openings in this "cold" area. Also in the interest of the largest possible heat transfer surface and a pressure-stable design of the end face of the pressure vessel on the hot side, the end wall, seen from the outside, is also concavely curved and the piston is adapted to this curvature of the end wall. Since this end wall is subjected to high temperatures from the burner, this end wall on the burner side is advantageously provided on its peripheral edge with an annular cooling channel, which accordingly has coolant supply and return connections.

Apart from the fact that the "hot" regenerator can also be arranged elsewhere in the pressure vessel on its hot side, an embodiment is preferred in that the "hot" regenerator is integrated in the piston which essentially limits the hot working volume on the piston side. As a result, when the piston is in the highest position, the regenerator comes into direct contact with the end wall and longer feed paths of the hot operating gas to the regenerator are eliminated.

In the sense of short flow paths and a compact design, the task set out is alternatively solved by a machine characterized by the features of claim 18.

In this embodiment according to the invention, it is provided that the piston liner is designed as a heat exchanger wall, and according to this embodiment the space for the control gear limits the cold working volume by means of easily insertable heat insulation material.

The regenerative heating and cooling machine according to the invention, including further advantageous refinements, will be explained in more detail below with the aid of exemplary embodiments.

Fig. 1

einen Längsschnitt durch die Wärme- und Kältemaschine;

Fig. 2, 3

bauliche Einzelheiten bezüglich der Steuerelemente;

Fig. 4

im Schnitt einen der Maschine bzw. dem Brenner zuzuordnenden Luftvorwärmer;

Fig. 5

vergrößert einen Schnitt durch eine besondere Ausführungsform des warmen Arbeitsvolumens;

Fig. 6

einen Schnitt durch eine weitere und bevorzugte Ausführungsform der Maschine und

Fig. 7A-M

die Bewegungsschemata der Kolben, jeweils in Verbindung mit dem p-v-Diagramm.

It shows schematically

Fig. 1

a longitudinal section through the heating and cooling machine;

2, 3

structural details regarding the controls;

Fig. 4

on average one air preheater to be assigned to the machine or burner;

Fig. 5

enlarges a section through a special embodiment of the warm working volume;

Fig. 6

a section through a further and preferred embodiment of the machine and

7A-M

the movement patterns of the pistons, each in connection with the pv diagram.

With reference to FIG. 1, the machine consists in a known manner of a pressure-tight housing 1 with two pistons 2, 3 which are linearly and coaxially movable therein, which together limit a warm working volume 5, and of which one piston 2 in the housing 1 is a hot, externally by means of a burner 22 subjected to heat (6) and the other piston 3 limits a cold working volume 7, the three variable working volumes 5, 6, 7 being interconnected with the interposition of regenerators and heat exchangers, and wherein in the housing 1 a control gear S is arranged for the pistons 2, 3. For such a machine it is now essential to solve the problem that the housing 1 is designed as a tubular pressure vessel 1 'with flow and return connections 10 to 13 for two heat transfer circuits, and all the regenerators 8, 9 and heat exchangers 14, 15 in the pressure vessel 1 are arranged that further a piston liner 16 with overflow openings 17, 18, 19 leading to the working volumes 5, 6, 7 is arranged in the pressure vessel 1 ', and that in the pressure vessel 1' the heat exchanger 15 for the one heat transfer medium on the one hand the cold working volume 7 and on the other hand delimits a space 70 in which the control gear S which is operatively connected to the pistons 2, 3 is arranged. In the piston positions shown, the hot and cold working volumes 6, 7 cannot be seen in FIG. 1, but can be seen in FIGS. 7A-J, in which the individual movement processes of the two pistons 2, 3 are shown, each with an adjacent pv diagram , in which the pressure orientations in the working volumes are indicated with corresponding arrows. For reasons of clarity, the regenerators 8, 9 and the heat exchangers 14, 15 including the heat exchanger, to which heat is supplied from the outside, are in contrast to the exemplary embodiment in FIG. 1 in addition to the actual one and illustrated only schematically in FIG. 7.

The flows of both the operating gas and the heat transfer media in the heating and cooling circuits to be connected, which are not shown, during operation of the machine require no further explanation, since nothing else arises in this regard than in the known Vuilleumier process.

In the illustrated and preferred embodiment, the "hot" regenerator 8 is integrated in the manner shown in the piston 2, which limits the hot working volume 6. Behind or below the regenerator 8, a channel 8 ′ ensures an outflow of the hot operating gas to the overflow openings 17 to the heat exchanger 14 and into the warm working volume 5.

For the reasons mentioned, the end wall 23 opposite the burner 22, viewed from the outside, is concavely curved, and the piston 2, with its integrated regenerator 8, is correspondingly adapted to this shape of the end wall 23.

Since the connecting wall 23 assumes a high temperature, this is, as shown, provided with an annular cooling channel 24, the flow and return connections 24 'of which are suitably integrated into a heating circuit, but which can also be connected to a separate circuit.

The heat exchanger 15 delimiting the space 70 on the cold side KS is also concave towards the piston 3, as seen from the outside, and likewise the piston 3 on the side of the cold working volume 7. The curvature of the heat exchanger 15 is somewhat less, at least in the peripheral edge regions held as that of the surface of the piston 2 facing this, whereby the operating gas is quasi squeezed out discharged to the cold working volume 7 and fed to the regenerator 9.

With reference to FIG. 5, a partition wall 32 provided with through-flow openings, which also divides the inflow space 26 to the heat exchanger 14, and advantageously in the through-flow openings, may be arranged advantageously, but not necessarily, centrally and stationary in the warm working volume 5 between the pistons 2, 3 additional regenerators 33 are arranged. The prerequisite for this is that the heat exchanger 14 which can be connected to a heating circuit is arranged on both sides of the overflow opening 18 between the piston liner 16 and the pressure vessel wall 1 "and this heat exchanger 14 on the cold side KS of the" cold "regenerator 9 also in the intermediate space 25 of the piston liner 16 and the pressure vessel wall 1 "is connected upstream.

The remaining free spaces in the intermediate space 25 are filled with heat insulation material 27 while keeping the inflow spaces 26 assigned to the overflow openings 17, 18, 19 free, which, correspondingly preformed and dimensionally stable, is simply inserted into the pressure vessel 1 'when the machine is assembled.

Without affecting the compact design of the machine, the two pistons 2, 3 are provided with piston rods 20, 21, which together engage in the space 70 in which current-controllable and elastic control elements for the piston movements are arranged. As can be seen from FIG. 3, the piston rods 20, 21 engage with their piston rod ends 20 ', 21' between two E-magnets 28, 29 which are spaced apart from the maximum piston stroke H. Each piston rod end 20 ', 21' is arranged clamped between two compression springs 30, 31 supported against the walls of the space 70, the piston rod 20 of the piston 2 delimiting the hot working volume 6 passing through the piston rod 21 of the other piston 3, which is designed as a tube, and the piston rod ends 20 ', 21' are provided with two-arm cross arms 20 ", 21", ie, only these cross arms 20 ", 21" engage in each of the exemplary embodiment between the E-magnets 28, 29 and the compression springs 30, 31.

With a correspondingly program-controlled energization of the E-magnets 28, 29, it is possible in this way to intervene in the movement process of the two pistons 2, 3, and the unavoidable friction losses in the machine can also be compensated for at the same time. In order to keep the control energy to be supplied as low as possible, the necessary and controllable e-magnets 28, 29 are advantageously combined with permanent magnets (not shown), so that the controlled energization of the e-magnets 28, 29 only affects the piston positions or Movement phases limited in which the pistons 2, 3 are held. With this design, the machine can be operated as follows, assuming a middle position (warm volume 5 = 0) (see FIGS. 7A-J):
Both pistons 2, 3 go up. When the maximum position is reached, the upper piston 2 is held in place and the lower piston 3 goes down. When this has reached its lowest position in which it is held, the upper piston 2 is released and moves to the lower piston 3, after which both pistons 2, 3 go up together again, etc. Intervene in a way that regulates the piston movements and thus regulate the output, because without having to change the external heat input through the burner 22, the holding period of the pistons 2, 3 can be changed by appropriately controlled energization of the e-magnets 28, 29.

In order to create favorable pressure ratios in the warm volume 5 between the two pistons 2, 3 in relation to the dimensioning of the piston area delimiting the hot volume, ie to increase the "residual Stirling effect", training is provided for this purpose (see FIGS. 1 and 5) that the piston 2 delimiting the hot working volume 6 is provided with a central piston extension 40 on its piston surface 2 'delimiting the warm working volume 5, which plunges into a Form-fitting recess 41 of the other piston 3 engages, the piston rod 20 being arranged on the bottom 42 of the piston extension 40 and the piston rod 21 being arranged on the bottom 43 of the recess 41. The in Fi. 1, 5 indicated seals 45 are not absolutely necessary, since the space 44 is accommodated in the closed housing 1 and there is nothing to the extent that the equipment (for example helium) is also in this space 44 or can get into it. The space 44 in the recess 41, which also changes during the piston movements, is expediently connected to the gas-carrying spaces via a bypass line (not shown).

The burner 22, the piston liner 16 and the pressure vessel 1 'and the latter, in particular in connection with the heat exchanger 15 or the space 70, are now briefly mentioned.

In adaptation to the concavely curved end face 23, the gas burner 22 is designed in the form of a mushroom-head burner, to which a heat exchanger 22 (see FIG. 4) provided with spiral chambers is assigned, through which the hot exhaust gases flow on the one hand and a cooling medium (heating water) and the fuel-air mixture for the burner, as is illustrated in FIG. 4 with corresponding arrows.

As far as the pressure vessel 1 'is concerned, the base 46 carrying the heat exchanger 15 is welded into the pressure vessel 1' in the exemplary embodiment shown. However, it is also possible, as is readily conceivable, to flange-mount this base 46 in a pressure-tight manner, which has the advantage of being able to pull out the two pistons 2, 3 together with the control elements and to be able to replace them if necessary. The same applies to the piston liner 16, which is preferably made of ceramic, between the lower edge 16 'and the bottom 46 of which a resilient ring 47 is arranged.

The embodiment shown in FIG. 6, which is preferred and which has a much cheaper and simpler structure, works on the same principle as explained for FIG. 7. For this embodiment, the corresponding reference symbols are used essentially and for the essential parts.

This embodiment is characterized in that the piston running surface 16 according to FIG. 1 is designed here as a heat exchange wall 16 'between the heat transfer media and the gas side and with this wall 16' in the region of the piston 3 on the cold side on the gas side includes the regenerator 9 and the other separates the spaces 50, 50 'carrying heat transfer media from one another. Here, in the exemplary embodiment, the wall 16 'is provided with helical gears 51 which are pronounced with respect to the pressure container wall 1 ".

The entire relatively complex arrangement of the heat exchanger 15 according to FIG. 1 below the piston 3 is omitted here, since this now comprises the lower half of the piston 3 working on the cold side KS. Only the heat insulation 27 is to be arranged downward toward the space 70 shown in cross section in FIG. 6. The working volumes for the gas side are also denoted here by 6, 7, between which and the working space 5 the gas flows back and forth along the gaps between the pistons 2, 3 and the heat exchange wall 16 'in accordance with the piston movements.

In the exemplary embodiment shown in FIG. 6, the regenerator 8 is also integrated in the piston 2. However, it is also possible to arrange the regenerator 8 stationary there instead of the upper heat insulation 27.

Instead of using control elements for the piston control, as explained in relation to FIGS. 1-3, the rest of the spring (in FIG. 1 on the right side) for the “cold” piston 3 should have a so-called negative spring characteristic, as indicated in Fig. 6 below, in the room 70 mechanical Control elements, for example in the form of a cam drive, are also in question, which also applies to the embodiment according to FIG. 1 of the machine.

Claims (23)

1. Externally heated regenerative heat and cold generating machine working according to the Vuilleumier cyclic process, consisting of a pressure-tight housing (1) with forward-flow and return-flow connections (10 to 13) for two heat exchange circuits and with two pistons (2, 3) which are movable linearly and coaxially therein and jointly delimit a hot working volume (5) and of which one piston (2) delimits, in the housing (1), a hot working volume (6) subjected to heat externally by means of a burner (22) and the other piston (3) delimits a cold working volume (7), the three variable working volumes (5, 6, 7) being connected to one another, with regenerators and heat exchangers interposed, and there being arranged in the housing (1) a control gear (S) for the pistons (2, 3), all the regenerators (8, 9) and heat exchangers (14, 15) and a piston sleeve (16) with overflow orifices (17, 18, 19) leading to the working volumes (5, 6, 7), characterized in that the housing (1) is designed as a tubular pressure vessel (1') accessible only from the piston gear side and closable in a pressure-tight manner there, and in that, in the pressure vessel (1'), the heat exchanger (15) for one heat exchange medium delimits, on the one hand, the cold working volume (7) and, on the other hand, a space (70), in which the control gear (S) operatively connected to the pistons (2, 3) is arranged.
2. Machine according to Claim 1, characterized in that the two pistons (2, 3) are provided with piston rods (20, 21) which jointly engage into the space (70), in which current-connectable and elastic control elements for the piston movements are arranged.
3. Machine according to Claim 1 or 2, characterized in that the "hot" regenerator (8) is arranged so as to be integrated into the first piston (2), and the latter delimits the hot working volume (6) essentially on the piston side.
4. Machine according to one of Claims 1 to 3, characterized in that a burner-side closing wall (23) of the pressure vessel (1') is provided at its circumferential edge with an annular cooling duct (24).
5. Machine according to Claim 4, characterized in that the closing wall (23) is curved concavely, as seen from outside, and the first piston (2) having the integrated regenerator (8) is designed to be adapted correspondingly to this curved shape of the closing wall (23).
6. Machine according to one of Claims 1 to 5, characterized in that the heat exchanger (15) delimiting the space (70) is likewise curved concavely towards the other piston (3), as seen from outside, and the other piston (3) is designed to be curved correspondingly on the side of the cold working volume (7).
7. Machine according to one of Claims 1 to 6, characterized in that the heat exchanger (14) connectable to a heating circuit is arranged on both sides of the overflow orifice (18) between the piston sleeve (16) and the pressure vessel wall (1"), and this heat exchanger (14) is preceded, on the cold side (KS), by the "cold" regenerator (9) likewise in the interspace (25) of the piston sleeve (16) and the pressure vessel wall (1").
8. Machine according to Claim 7, characterized in that the remaining interspace (25) is filled with heat-insulating material (27), with inflow spaces (26) assigned to the overflow orifices (17, 18, 19) being kept free.
9. Machine according to one of Claims 5 to 8, characterized in that the burner (22) is designed as a mushroom burner adapted essentially to the concave curvature of the closing wall (23).
10. Machine according to Claim 1 or 9, characterized in that the burner (22) is assigned a heat exchanger (22') for preheating the burner air.
11. Machine according to Claim 2, characterized in that the piston rods (20, 21) engage with their piston-rod ends (20', 21') between two electromagnets (28, 29) spaced according to the maximum piston stroke (H), and each piston-rod end (20', 21') is arranged so as to be clamped between two compression springs (30, 31) supported against the walls of the space (70), the piston rod (20) of the piston (2) which delimits the hot working volume (6) passing through the tubular piston rod (21) of the other piston (3), and the piston-rod ends (20', 21') being provided with two-armed transverse jibs (20", 21") which in each case engage between electromagnets (28, 29) and compression springs (30, 31).
12. Machine according to Claim 1, characterized in that the piston (2) delimiting the hot working volume (6) is provided, on its piston face (2') delimiting the hot working volume (5), with a central piston extension (40) which engages into a correspondingly shaped recess (41) of the other piston (3), one piston rod (20) being arranged on the bottom (42) of the piston extension (40) and one piston rod (21) being arranged on the bottom (43) of the recess (41).
13. Machine according to Claim 12, characterized in that the space (44) delimited by the piston extension (40) and the recess (41) is connected via a bypass conduit to the machine interior carrying fuel gas.
14. Machine according to one of Claims 1 to 13, characterized in that there is arranged centrally and stationarily in the hot working volume (5), between the pistons (2, 3), a partition (32) which is provided with throughflow orifices and also divides the inflow space (25) between the two parts of the heat exchanger (14) and in the throughflow orifices of which additional regenerators (33) are arranged.
15. Machine according to Claim 6, characterized in that the curvature of the heat exchanger (15) is smaller, at least in the circumferential edge regions, than that of that face of the piston (3) which faces the said heat exchanger.
16. Machine according to one of Claims 1 to 15, characterized in that the piston sleeve (16), preferably formed from ceramic, is mounted elastically in the axial direction on the cold side (KS) of the pressure vessel (I').
17. Machine according to one of Claims 1 to 16, characterized in that the heat exchanger (15) is arranged on the pressure vessel (I') in a pressure-tight manner, not releasably.
18. Externally heated regenerative heat and cold generating machine working according to the Vuilleumier cyclic process, consisting of a pressure-tight housing (1) with forward-flow and return-flow connections (10 to 13) for two heat exchange circuits and with two pistons (2, 3) which are movable linearly and coaxially therein and jointly delimit a hot working volume (5) and of which one piston (2) delimits, in the housing (1), a hot working volume (6) subjected to heat externally by means of a burner (22) and the other piston (3) delimits a cold working volume (7), the three variable working volumes (5, 6, 7) being connected to one another, with regenerators and heat exchangers interposed, and there being arranged in the housing (1) a control gear (S) for the pistons (2, 3), all the regenerators (8, 9) and heat exchangers and a piston sleeve (16) with overflow orifices (17, 18, 19) leading to the working volumes (5, 6, 7), characterized in that the housing (1) is designed as a tubular pressure vessel (1') accessible only from the piston gear side and closable in a pressure-tight manner there, and in that the piston sleeve (16) is designed as a heat exchange wall (16') between the heat exchange media and the gas side, and both the hot side (WS) and the cold side (KS) of the machine are covered by this wall (16'), the wall (16'), in the region of the piston (3) of the cold side, on the one hand enclosing the regenerator (9) on the gas side and, on the other hand, separating from one another the spaces (50, 50) carrying the heat exchange media, and gaps for the throughflow of the working gas and of the heat exchange media being formed in the piston sleeve (16) designed as a heat exchange wall (16'), and in that a space (70), in which the control gear (S) operatively connected to the pistons (2, 3) is arranged, delimits the cold working volume (7).
19. Machine according to Claim 18, characterized in that the wall (16') is provided with helically extending passageways (51) embossed relative to the pressure vessel wall (1").
20. Machine according to Claim 18 or 19, characterized in that the regenerator (8) is arranged in the first piston (2) or stationarily, on the gas side, within the upwardly extended heat exchange wall (16').
21. Machine according to Claim 18, characterized in that the two pistons (2, 3) are provided with piston rods (20, 21) which jointly engage into the space (70), in which current-connectable and elastic control elements for the piston movement are arranged.
22. Machine according to Claim 21, characterized in that a burner-side closing wall (23) of the pressure vessel (1') is provided at its circumferential edge with an annular cooling duct (24).
23. Machine according to Claims 20 and 22, characterized in that the closing wall (23) is curved concavely, as seen from outside, and the piston (2) having the integrated regenerator (8) is designed to be adapted correspondingly to this curved shape of the closing wall (23).

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