DE2356841A1 - LOW TEMPERATURE COOLING MACHINE - Google Patents

Description

The invention relates to a low-temperature refrigeration machine with temperature gradation and, in particular, a low-temperature refrigeration machine in a stepped design with temperature gradation ^ the at

(Can emit cold temperatures more than one temperature level .. The basic principle the device is on cryogenic refrigeration machines j, that described in US Pat. No. 2,906,101 Circular process work and, in particular, according to the form of the circular process.fc described in US Pat. No. 2,966,035. The invention is also applicable to devices for generating cold according to the Stirling and Vuilleumier cycle work*

In the construction of a low-temperature air conditioning machine Temperature graduation, which has two or more cold chambers, it is. due to the mass flow notv / endigv j; ede cold chamber ' 'to be interpreted in such a way that it has a smaller volume than that of the • Colds at the next · higher. Gives temperature level; .. This The requirement for the decreasing volume of the cold chambers is different Overriding viewpoints; how. Achieving a simple Construction * maximum effectiveness of the regenerator and reduction

the heat losses to a minimum - especially those heat losses that occur due to heat leaks through heat conduction and ^: piston movement. The most favorable configuration that meets these requirements is a stepped design, that is to say a refrigeration machine with a housing _f that is in the form of hollow cylindrical sections with decreasing size. Diameters, constructed and sealed to form a fluid-tight space in an appropriate manner, and with ■ rigidly connected pistons of different diameters, which are 'movable back and forth in the housing sections. Due to their stroke movement, the pistons ■ form cold chambers with decreasing. Diameter, whereby the shrinking ^{Kältekammer-:} volume yield "Thus, in this conventional staged: construction of the chamber diameter, the only design parameter 'can be changed to control the volume ratio of two or more cooling chambers, since the pistons with each rigid' are connected to each other and all perform the same stroke.

However, Us is, impracticably, the diameter of the colder cold chambers regardless of various limiting factors

to change arbitrarily. For example, in a refrigeration machine in a stepped design in which the regenerators are arranged inside the pistons (and this is generally the case), the regenerator pressure drop and the thermal performance of the regenerator are at least partly determined by the regenerator diameter (and thus by the piston diameter) as well as by the length of the regenerator. This fact in turn results in relatively strict limitations with regard to the extent _r to which the diameter of the pistons, which form the cold chambers for lower temperatures, can be reduced the Hubweges- for those pistons ,, soft, the volume of the cold chambers with lower temperatures form Da., only a single drive means for this Kolbenab-; sections is of decreasing diameter Pre See, - is the previously customary rigid mechanical connection between the piston sections zur- Modification; of the piston stroke not usable.

The invention is based on the object of an improved
To create a low-temperature refrigeration machine in a stepped design with temperature gradation, in which the volume of the cold chambers,
that work at lower temperature ranges, in a simpler way
v. May be ^T else by changing the stroke of the reciprocable .Kolbenabschnitts optimally designed that forms the volume. Furthermore, a low-temperature refrigeration machine should be designed in such a way that lower temperatures can be reached! than with a refrigeration machine of the same size and configuration j with stepped piston, the sections of which are rigidly connected to one another j

'are connected. Furthermore, such a low-temperature cold i

, machine are designed so that the mass flow for each!

Stage optimally designed, the regenerator efficiency increases j

: and the p.V diagram of any stage for a desired one;

.Performance can be optimized ·. ~]

According to the invention, the adjustment of the piston stroke
by a connecting or coupling device for the Kolbene.b cuts made possible, which allows engagement between the piston sections in sequence and thereby causes the
Pistons with the largest diameter one or more pistons j with smaller diameters a reciprocating motion over one
^; Granted stroke, which is smaller than that, which the piston with
the largest diameter. It was found that it
: is possible by changing the ratio of the stroke paths that
Temperature 'and the cooling capacity for each level within
! to vary certain limits, the overall performance
'of the refrigeration machine by setting the relative piston! To bring shifts to an optimum and to reduce the losses associated with the regenerators for lower temperatures, while taking advantage of the above-mentioned optimum design features, such as minimal heat leakage losses through conduction and. i can maintain movement processes and the simplicity of the overall structure.

A cryogenic refrigerator that achieves the object of the invention ^; solves, is designed so that an expansible high pressure fluid from i

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a high-pressure fluid source can be introduced into two or more cold chambers with variable volumes, which work at a different temperature level, can let undyexpanded low-pressure fluid flow out of these into a low-pressure reservoir. The fluid is directed to the cold chambers via a flow path that includes regenerators and is returned from the chambers via the same flow path. The cold chambers have diameters which become smaller as the temperature level decreases, and their variable volumes are determined by pistons which can be moved back and forth and which are coupled to one another in such a way that the pistons engage . in turn results in such a way that the piston with the largest part j diameter gives the other or the other piston a reciprocating movement over predetermined and controlled stroke paths, wherein.; these stroke paths are smaller than that which the piston with the largest diameter executes.

i!

The refrigerating machine according to the invention can be used in devices whose operation is designed for cyclic processes according to US Pat . The invention can also be used in devices which are based on the Stirling cycle, as described in US Pat

2,657,553, and according to the Vuilleumier cycle work, which is described in US Pat. No. 1,275,507.

A variable connection between pistons has been used in in-line refrigerators, where each piston moves in its own separate concentric housing that extends up into the warm end of the refrigerator (U.S. Pat

3 673 809). This makes it possible to provide seals only on the warm end. The device according to US Pat. No. 3,673,809 is suitable for low-temperature refrigerating machines in which a considerable overall efficiency can be dispensed with in order to achieve a simple construction. This device is particularly suitable for the construction of larger refrigeration machines in which! ■ relatively large heat losses can be accepted. ^:

4098 2 270 33 8 " ⁵ "

! ■ 'ν

¹ In the device according to US Pat. No. 3,673,809, all pistons have essentially the same diameter, which is why the stroke path i is the only design parameter required to achieve the required; the desired proportions between the cold chamber volume can be set. Therefore, the construction and operation of a small series refrigeration machine, as described in US Pat. No. 3,673,809, involves almost insurmountable problems when very low temperatures and relatively high efficiencies are to be achieved. This is due to j

i: that, because the diameter of the cold chambers for lower temperatures must be essentially the same as that of the cold chamber at the highest temperature, the stroke of the pistons, ·; Many marriages form the chambers for lower temperatures, - extremely short: must be, which results in problems with regard to setting and control. In addition, the high thermal losses! Due to excessive conduction through the elongated chamber area and due to the large heat leaks caused by movement processes over the elongated piston surfaces, this is a major factor in avoiding the construction of a powerful low-temperature refrigeration machine, especially for small sizes, the cold at low temperatures, for example below 15 ⁰ K.

The device according to the invention makes it possible to compensate for the piston and cylinder diameter factors with the piston stroke path, so that optimum operating properties are obtained for any size of cryogenic refrigeration machine and in particular for such
deliver.

receives that up to about 20 watts of cold at 10 ⁰ K or below

The invention includes the features of construction, the combination of Elements and the arrangement of parts as explained below.

For example, embodiments according to the invention are explained in more detail below with reference to the drawings, in which

Fig. 1 is a simplified longitudinal section of a two-stage j

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i - β -

j shows the low-temperature refrigeration machine based on the invention and according to that described in US Pat. No. 2,966,035 " ; Circular process works. The associated components are also indicated.

FIG. 2 shows a modification of the refrigeration machines according to FIG. 1, with the regenerators outside the housing the refrigeration machine are arranged. ■.

: Fig. 3 -is a longitudinal section through a ^{schematiseher:} three-stage refrigerating machine formed according to the invention

is and according to the circle described in US Pat. No. 2,966,035 process works, with the elements of a Joule-Thomson circle are shown, with which the cold generated can be used to liquefy helium v / ground.

4 to 7 are cross-sectional representations of four embodiments of a variable coupling device between the pistons which can be provided in the refrigerating machines according to FIGS. 1 to 3.
i. ■ ■

ι FIGS. 8 to 11 explain the stages in the mode of operation; the variable coupling device according to FIGS. 4 and 5.

Fig. 12 illustrates a variation of the last stage of the j operation when the embodiment of the variable coupling in-I direction of Fig. 7 is used.

FIG. 13 is a p, V diagram for a typical cryogenic refrigerator that operates according to the procedure given in U.S. Patent No. 2,966,035 \ cycle, the supply of high pressure fluid into the refrigerating machine is stopped early.

^! 14 is a p, v diagram for the colder cold chamber; i a two-stage refrigeration machine, which forms according to the invention and with the coupling device according to FIG. 4 or 5 ver j

see is. '. . ; .-:. - -. ._ 7 _

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■ - 7 - ■ -; ■■.

15 is a p, v diagram for the colder cold chamber a two-stage refrigeration machine according to the invention is designed and provided with the coupling device according to FIG. _. * --..- '

Fig. 16 shows a cross section of an embodiment, in which the variable coupling device between the pistons a combination of a surface system and a holding device

.ist, which is attached to the housing of the chiller.

¹ Fig. 17 to 19 explain the working stages of the refrigeration machine according to Fig. 16. · -

Figure 20 is a p, V diagram for the colder cold chamber a two-stage refrigeration machine, which is designed according to the invention and provided with the coupling device according to FIG is. . .

Fig. 21 is a simplified longitudinal section of a two- : stage refrigeration machine according to the invention, which after in the j US Pat. No. 2,906,101.

I "

Fig. 22 is a schematic longitudinal section of a two-stage Refrigeration machine according to the invention, which after the Stirlingl Circular process works.

ί Fig. 23 is a simplified longitudinal section of a Zweij stage refrigeration machine according to the invention, which operates according to the Vuilleumier cycle specified in US Pat. No. 1,275,507.

It should be noted that in the following description of the deep. temperature chiller according to the invention ⁵ expressions such as'"warm" I and "cold" are to be regarded as relative and "above" and "below"! For _v simplify the explanation, and to adapt the 'Description of refrigerating machine with two, three or more stages

.. 409822/0338

the expressions "largest diameter", "smallest diameter" f

¹ knife "etc. in connection with pistons, displacers and refrigeration- i ¹ ■ ■ I

; chambers are generally used even if there are only two stages. It also appears expedient to designate a movable body in the general explanations as a "piston" and to use this expression in its broadest sense, so that a displacer is also to be understood by it. The term "piston" is intended to encompass all sliding bodies that are contained in a cylindrical! Vessels are movable regardless of whether their surfaces are exposed to different pressures or not, while the term "displacer" is used for those sliding bodies which have essentially no pressure on their surfaces ¹ difference are exposed. ι

¹ The device according to FIG. 1 is a two-stage low-temperature refrigeration machine which, according to the so-called non-working circuit ■ ^; process according to US Pat. No. 2,966,035 works. This cold ^! . machine has a stepped, fluid-tight housing 10; ¹ which consists of a section 11 with a larger diameter and an I. The smaller diameter portion 12 is formed with this

the two sections are connected to one another via an annular shoulder 13. In the housing section 11 forms a ver ,

i j

^! Dränger 14 with a larger diameter due to its displacement movement, a warm chamber 15 with a variable volume and a first - cold chamber 16 with a variable volume. A second cold chamber 18 for a lower temperature is formed in the housing section 12 i by means of a displacer 17 with a smaller diameter. ! The displacer 14 is mechanically connected to a drive device 19 via a rod 20 and to the displacer 17 of smaller 'diameter via a variable coupling device 25! den, which is shown in simplified form and has a collar 26 at the upper or warmer end of the displacer 17 and a lip 27 which can come to rest against the collar and is within an open cavity 28 at the lower or colder end of the displacer 14 extends inward, this lip is designed so that the upper, with the

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--9 - 235684 Λ.

The end of the displacer 17 provided with a collar with a low | Play in the cavity 28 up and down can be moved. Example 4-wise embodiments of such variable coupling means are shown in detail in FIGS. 4 to 7 and are described later. A suitable seal 21 or 22 (either an active or automatic or a passive seal) is provided for the two displacers 14 and 17 and, if necessary, a certain type of shock absorber device, such as a leather washer 23 at the colder end of the displacer 17 or on the inner end wall of the housing section 12.

The displacer 14 is provided with a regenerator 30 and the displacer 17 is provided with a regenerator 31. The basic one! The flow path in the refrigeration machine comprises the warm chamber 15 * 'one or more fluid channels 32 which are provided for connection between the chamber 15 and the regenerator 30, the annular space formed by the play around the collar 26 and the lip 27,! dsn over the regenerator 30 with the first cold chamber 16 in conjunction Binding _r is the regenerator 31 to the regenerator 30 | ^: is directly connected by the cavity 28, one or more fluid channels 33, which are provided for connection between the regenerator 31 [and the second colder cold chamber 18, and! finally the cold chamber 18 itself.

The high pressure fluid is supplied by a high pressure fluid source, for example the outlet side of a compressor 34, via a line 35 and a slide 36, while the low pressure fluid is supplied to a lower pressure reservoir, for example the inlet side of the compressor 34, via a line 37 and a Slide 38 is pulled off. This flow path of a typical closed circuit comprises: too, a suitable cleaning system for the fluid to _r as indicated at 39 ^. On the other hand, it is not necessary in an open circuit that the high-pressure supply system 40 (for example a compressed gas source) is connected to the low-pressure reservoir 41 (for example the atmosphere).

- '- - - 10

4ftS & 22 / '& 33 &

indicates. But it is also possible to use a pneumatic drive device as described, for example, in U.S. Patents 3,045,436 and 3,188,819. .

■ Cold is emitted in two temperature ranges, with one; Higher temperature level (typically 30 to 120 ⁰ K) of '. the fluid in the cold chamber 16 via a heating station 42 and; at a lower temperature level (typically 8 to 25 ⁰ K)! ! of the fluid in the cold chamber 18 via a heating station 43. I

The device of Fig. 2, in which the same components

the same reference numerals as used in Fig. 1 are used I thereby a modification of the device of FIG. 1 is that the regenerators 48 and 49 are arranged outside the housing 10!

are and the flow path of the fluid in addition to the Regenera- | j tor en 48 and 49 fluid lines 50 to 53 comprises. The one ^!

fanned out due to hatched displacers 54 and 55 ί

■ can be hollow or compact.

The three-stage refrigeration machine according to FIG. 3 has a housing 60 j j with three housing sections 61, 62 and 63, which have different ¹ borrowed diameter and in which three displacers 64, 65 and 66 are displaceable, with seals 67, 68 for sealing and 69 are provided. The regenerators 70, 71 and 72 are arranged within the displacers assigned to them. A variable: coupling device 73 forms the drive device for the displacer 65 and a corresponding coupling device 74 that for the displacer 66. The displacers determine cold chambers 75, 76 and 77 with variable volumes, each of which is assigned a heating station 78, 79 and 80 during their displacement movement is. The flow path in the refrigeration machine is identical to that according to FIG. of the three-stage refrigeration machine according to FIG. 3, the middle displacer i65 with both the displacer 64 and the displacer 66 | j with the smallest diameter via a variable coupling device [is connected, it is also within the scope of the invention, ■

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- ■ ΐΐ -

ι only a variable coupling device in a refrigeration * ! to use a machine with three or more stages, with the. Variable coupling between any two displacers provided can be. The refrigeration machine according to FIG. 3 also has a Joüle-Thomson circle with which, if necessary, a gas' ! can be liquefied. As is known, this JouleiThomson circle three heat exchangers 81, 82 and 83 through which the high pressure fluid in the circuit via non-contact heat exchange ! between the high pressure fluid in line 84 and the returning fluid Low pressure fluid in line 85 is cooled. ! The high pressure fluid is also in corresponding temperature ranges by contactless heat exchange with the fluid in the Cold chambers via the heat stations 78, 79 and 80 in heat exchangers 86, 87 and 88 chilled. There is also a last one • Joule-Thomson heat exchanger 89 and an expansion valve 90 j intended. The liquefied gas is collected in a vessel 91 from which the low-pressure gas via line 85 through again the circle is directed.

Figures 4 through 7 illustrate three exemplary embodiments of variable coupling devices, for example the coupling device 25 according to FIGS. 1 and 2 and the coupling devices 73 and 74 according to FIG. 3. As an example, the refrigerating machine used according to FIG. 1 and in FIGS. 4 to 7 The same reference numerals are used for the same components.

In the embodiment according to FIG. 4, a direct flow path between the two regenerators 30 and 31 is provided. Of the Collar 26 at the upper end of the displacer 17 with a smaller diameter is designed as a threaded cap 100, which are screwed into the thread on the inner wall 101 of the displacer 17 is. The cap 100 has a central opening 102 which forms a passage into the regenerator 31 through one above the other layered disks 103 is shown. The intended for the system lip 27 is expediently as part of a Threaded cap 104 formed into the thread on the inner wall 105 of the displacer 14 is screwed in. When the cap is 10 '»·

409822/0338

I is screwed in, its outer flange 106 lies in a plane J with the lower edge of the outer wall 107 »so that a smooth; Boundary surface results. The regenerator 30 terminates in a. perforated disc 108, which rests on the upper edge of the cap 104 and serves to hold the lead balls, discs or other filler pieces which form the regenerative material in the regenerator The upper side of the collar 26 comes to rest in order to move the displacer downwards. During the shifting movement upwards, the collar 26 rests against the lip 27.

ι It may be desirable to be able to vary the amount by the , the stroke paths of the two displacers differ, that is '' a control of the length of the displacement path of the

'Drängers 14 should be desired before he rests on the displacer 17 comes. This can expediently be achieved by inserting an appropriately sized washer 99 into the cap 104, by which the edge height of the lip 27 is increased accordingly. It is also possible to use the covenant. 26 through a

; Row of two or more, equally spaced J replace pins extending radially outwardly from the top of cap 100, or any other suitable Provide engagement means which connect the piston with the smallest and largest diameter results when the latter moves in a direction that leads to an enlargement j of the volume of the cold chamber assigned to it.

In the embodiment of Figure 5, the variable coupling device is modified somewhat to provide a flow path of the basic type described in U.S. Patent 3,218,815. At the upper end of the displacer 17, the collar 110 is formed as part of this, and passages 111 for the fluid into the regenerator 31 are provided in the wall of the displacer! ■ The displacer 14 has a lower portion 112 having a diameter slightly smaller than I on the other part, so that \ is an annular space 113 is obtained for the passage of the fluid, in ί

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. which open a number of radially extending channels, of two of which are shown at 114. These channels lead into the Regenerator 30, which is limited at the bottom by a closed wall 115 is. The surface 116 of the cavity 28 serves as a contact surface for the displacer during the downward movement. the The direction of flow of the high-pressure fluid is indicated by arrows. It runs for the low-pressure fluid flowing back in the opposite direction.-The flow path at the Embodiment according to FIG. 5 gives thermal advantages, however these are partly due to a slightly higher pressure drop of the indirect flow path weakened.

6 shows a modification of the variable coupling device according to FIG. 4, with a pin 117 with a collar on the perforated disk 108 of the displacer 14 for engagement 118 is attached, which is designed so that it is attached to a

^: inwardly extending collar 11.9 ". around the opening of a hollow

; space 28a in the engagement end of the displacer 17 to rest comes. As a cover for the regenerator 31 is a perforated!

! Plate 108a is provided. The operation of the device according to Fig. 6 is identical to that of Fig. 4,

The variable coupling device according to FIGS. 4 to 6 is based on the frictional force of the seal against the pressure gradient, thus the displacer with the smaller diameter held in place until they come to concern at the other displacer. However, in some cases it may be desirable? An institution to provide that ensures that the displacer 17 did not carry out any undesired displacement movement. Such a device is shown in Fig. 7 in the form of a compression spring 116 ' notes ,, The action of such a spring is related with FIGS. 8 to 15 explained below

The use of the variable coupling means in the stepwise operating refrigerating machine according to the invention can be illustrated a considerable thermodynamic significance, the "best understood from the Figure 8 to 15 _0. Figs. 8 to 11 illustrate

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The operation of the coupling device at a j-fiction, modern apparatus, as shown in Fig. 1, the \ use of the embodiment illustrated in FIGS. 4 to 6. Coupling device. In FIGS. 8 to 11, the device components are not shown in detail, but only shown schematically, and the displacers with larger and smaller diameters are indicated by hatching for the sake of clarity.

In describing the operation of this device can; it can be assumed that a working cycle with the full \

j constant expulsion of essentially all of the cold i! Never the pressure fluid (except in the dead volume) from all refrigeration; ; chambers, i.e. chambers 16 and 18, begins. This makes it necessary to close the Mederdruckschieber 38! and to open the high pressure valve 36. By introducing the | High-pressure fluids into the device, the upper displacer is shifted upwards with a larger diameter (Fig. 9), so that! a first cold chamber 16 is formed with an increasing volume, while the displacer 17 due to the friction; the seal 22 (Fig.1) remains in its lowest position. After the displacer 14 has been displaced over a predetermined section j of its entire stroke, the variable coupling device causes the displacer 14 to engage the displacer 17 via the collar 26 and the lip 27 and raise it. In a preferred embodiment of this operating cycle, the high-pressure fluid is shut off before the cold chambers 16 and 18 reach their full volume (early shut-off). While the larger diameter displacer 14 moves upward, the volume of the cold chamber 18 increases. At the end of this upward movement, the stroke of the displacer 14 is I ₁ ^, while the stroke of the displacer 17 _{corresponds to the distance I 1} ~. Thus, the ratio of the final volumes of the cold chambers 16 and 18 is a function of I ₁₄ Zl ₁₇ and the diameter, the displacers 14 and 17.

When the maximum volume is reached (Fig. 10), the outlet slide opened. The friction of the seal is sufficient

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. Displacer 17 in the embodiment shown in Fig TO position to hold even if the off from the chamber 18 via the regenerator 31: causes flowing high pressure gas, that at the .Verdränger 17 ^wherein: a force acts upward direction. The displacer 14 is moved downward ^ to. the contact surface 109 of which comes to rest on the collar 26 of the displacer with the smaller diameter (Fig.11) _o The subsequent downward movement of both • displacers causes the final discharge of the fluid from the refrigeration machine _5, which then returns to the starting state for Another working cycle is brought (Fig. 8).

The effect of the variable coupling device for the refrigeration machine in the p-V diagram can be seen from FIGS. 13 and 14. Figure 15 illustrates a p _o, V-diagram for the first cold chamber of larger diameter is, and it shows a typical p, V curve for the cyclical process with early barrier. The volumes in these ppV diagrams are in arbitrarily selected units of the stroke path of the; As a result of the restriction of the displacement movement and the stroke of the Yerdrängers 17, the "p, V diagram shown in FIG. 14, which is essentially the right part of the p, V 13 is a result of the formation of these two different ρ, ν diagrams for the two cold chambers is a fuller p _? V diagram for the cold chamber with the larger volume, which in turn means that the fluid in this chamber _v is colder by a few degrees K. This in turn, combined with the formation of a larger displacement ratio (for example the ratio of the volume of the chamber with the larger diameter to the volume of the chamber with the smaller diameter), results in reduced regenerator losses, because the colder the fluid in the first The larger the cold chamber, the smaller the ^ T over the regenerator, which means that the fluid in the cold chamber is at the lowest temperature level u can reach a lower temperature or deliver more cold at a specified temperature. In addition, the regenerator that is assigned to the colder Kältekammei (for example the regenerator 31 in Fig. 1), normally.aus. formed by a number of lead balls, so that lead.

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has a high heat capacity at these low temperatures.

However, lead "is relatively low at these temperatures j specific heat C. By reducing the mass flow through 'the lead (which is achieved by reducing the temperature in the cold chamber

j is reached with the larger diameter and reduction of the volume of the ¹ cold chamber with the smaller diameter); the lead of a smaller temperature change ^ iT and it is thereby; by means of a more effective heat transfer device.

The use of the spring 116 in the embodiment according to FIG. 7 (changes the end of the stroke, as shown in Fig. 12, j which corresponds to the same operating point of the duty cycle, the i in Fig. 11 for a variable coupling device without the positive Holding effect of the spring is reproduced. The spring force j acts so that the displacer 17 is at a distance from the displacer 14 is held so that the displacer 17 is then displaced downward when the displacer 14 is moving starts down. This leads to a slightly modified p, V diagram for the chamber 18, as can be seen from FIG. However, the overall results of lower temperatures are

reduced mass flow into the cold chamber 18 and reduced Regenerator losses are essentially the same.

16 shows an embodiment of the device in which the variable coupling device between the displacers is a combination of a simple system between the displacers and an actuating and holding device which is only provided for the displacer with a smaller diameter. The lower portion of the refrigerating machine shown is of the same two-stage type as shown in Fig. 1 and the same reference numerals are used for the same components. In the embodiment of Fig. 16, the displacer 120 with a larger diameter (with the regenerator 121 and fluid \ channels 122) not connected to the displacer 123 of smaller diameter (with regenerator 124) by any mechanical coupling device, however, causes the displacer

- 17 -

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120 one. Downward movement of the displacer 12 3 when the lower Contact surface 125 of the displacer 120 on the upper surface of the perforated disc 127 comes to bear, which as permeable Cover for the regenerator 124 is used.

j ■ ■ ■

- There is no special mechanical connection between the

Displacement 120 and 123 must be used to control the ■ Upward movement of the displacer 123 and for setting: its stroke a certain device can be provided. j This has the shape shown in detail in Fig. 16. At the bottom 133 of the housing 12 is a pin 130 with a for the

. [Intervention provided collar 133, for example by means of a. j screw 132 attached and the colder / end of the displacer 123 is modified so that one engages the collar Paragraph 134 is present, extending from the mouth of the Cavity 135 extends inward. This cavity 135 is designed in such a way that a predetermined stroke path of the displacer 123 is possible before the approach 134 on the federal government 131 comes to rest. A compression spring 136 holds the displacer 123 while the periods of the work cycle in its uppermost position, irt those of the displacer 120 no downward force exerts on the displacer 123. The flow path of the fluid between the regenerator 124 and the cold chamber 18 is in essentially that described in US Pat. No. 3,218,815 and he includes radial passages 137 and an annulus 138.

The operation of the embodiment of FIG. 16 is shown in FIGS Figs. 17-20 are shown. As is apparent from Fig. 17, lie at the start of the operating cycle, the same conditions exist as for the device according to FIG. 1 in conjunction with FIG were specified. However, when the high pressure fluid in the chiller begins to flow in, a part of this occurs directly in the chamber 18, the volume of which immediately increases i will until it finally passes through the longitudinal dimension of the tenon 130th is limited. After the maximum volume has been reached in the chamber 18, the volume of the chamber 16 grows further. this J is different from the embodiment of Fig. 1, as a ver ! 18 and 19 with FIGS. 9 and 10 clearly shows.

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On the other hand, the downward shifting movements are at the | ! both devices, identical in terms of their results.
! 20j shows a p, V diagram for the colder cold chamber

18 of the refrigerating machine according to FIG. 16 shows that it;

is essentially equivalent to the left side of the p, V-slide.

gramms for the cold chamber with the larger diameter, like!

13 is apparent. ''

According to the invention, the device can be designed so that it operates according to the cycle process described in US Pat. No. 2,906,101, as shown in FIG. The device
according to FIG. 21 differs from that according to FIG. 1 in that j

; that the warm chamber 15 is not available. According to that!

; The difference between the two circular processes is provided by the work cycle "

a specific external mechanical energy instead j \ thermal energy j of the refrigerator of FIG. 1 is given corresponding to the non-working cycle according to Fig. 21. '

In FIG. 21, the same reference numerals as in FIG. 1 are used for the same components. As indicated above, the fluid-tight, stepped housing 10 is open on the top and the top
\ Section 140 is preferably configured to have a
has thicker wall than the remainder of the section of the housing
10. Some modification is to section 140 of the housing
required as the high pressure fluid directly into the
Initiated regenerator 30 and the low pressure fluid directly aui
the regenerator 30 must be expelled. This modification is shown in FIG. 21 in the form of a plurality of grooves 141 in the wall 140. The high pressure fluid is introduced into the device through line 142 and the low pressure fluid becomes
ejected over the same line. This line 142 corresponds to the line 35 and 37 according to FIG. 1. This external line
stands with the regenerator via the grooves 141, an outer one
Annular space 143, an annular groove 144 which is formed on the circumference of the displacer wall, and a number of radial channels 145 {in connection which lead into the regenerator 30. The flow path of the fluid between the chambers 16 and 1,8 via the Re.gene- '

: _ratpren_ 3_Q_und 31 Jcann identical to that in connection with the

. - ig -

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Fig. 4 xind 5 described. Sealing rings 146 and 147 are arranged in such a way that the displacer 14 rests in a fluid-tight manner on the inner wall of the housing section 140.

The advantages that can be achieved with the device according to FIG. 21 are essentially the same as those given for the device of FIG. In the device according to FIG. 21 can Changes to the flow path of the fluid can be made, as well as a spring as shown in Fig. 7 and the Aus, Guide form of the variable coupling device according to FIG. 16

can be used. ·

Figs. 22 illustrates the application of the invention, one embodiment of a Stirling engine, which briefly as a: may be described apparatus comprises an additional \ compressor piston which is displaceable in the housing to form a compressor chamber of variable volume which alternately serves as a high-pressure fluid source and as a low-pressure fluid reservoir. In the embodiment of the Stirling engine shown in FIG. 22, the expansion or cold-generating section of the housing 150 is of a stepped construction; formed separately from the compressor housing 151. However, the compressor chamber can be arranged in the same housing as the expansion chamber and the housings can be viewed as a single housing device. According to FIG. 22, the two housing parts are connected by a suitable fluid line 152 in which an aftercooler 153 is arranged. The line 154 serves for the passage of a cooling fluid through the aftercooler. The compression of the fluid in the machine takes place in the chamber 156 and it is brought about by a piston 157 which is driven by a suitable drive device 159 via a rod 158. In accordance with the invention, the expansion in the two expansion chambers 160 and M61 takes place through the sliding movement of a piston 162 of larger diameter, which is mechanically connected to the drive device 159 via a rod 163, and of a piston 164 of smaller diameter, the is slidable in the stepped housing .150, which consists of a section__165 with a larger diameter

409822/0338 " ² °"

j -

I and a section 166 with a smaller diameter. The pistons 162 and 164 are connected to one another in a variable manner, as is shown in detail with reference to FIG. 4 ι to 6 was described. Regenerators 167 and 168 are located within pistons 162 and 164, respectively.

A cold chamber 160 and a pure intermediate temperature chamber 170 are formed in the housing 150 by the displacement movement of the piston 162 with a large diameter. The flow-I off in the expansion section of the apparatus comprises a guided through idas headpiece 174 channel 173 which Zwischentemperatur- \ chamber 170, a passage 175, the regenerator 166, the first ■ expansion chamber 160 with a larger volume, the regenerator _(and the second Cold chamber 161 with a smaller volume. As far as the Stirling cycle is known, it will not be further described here. according to / after the device works according to FIG. 1, it follows that by setting the cold chamber volume by combining the design of diameter and piston travel essentially the same advantages of lower temperatures and / or greater cold capacity are achieved.

FIG. 23 explains the application of the invention to a low-temperature refrigerating machine which is based on the Vuilleumier cycle is working. The operation according to this cycle requires that a hot chamber and a chamber with an intermediate temperature and one or more cold expansion chambers are available these terms are to be understood as relative to any system. The basic device thus includes for the implementation of the Vuilleumier cycle in addition to one or more displacers for the formation of cold chambers with variable volume an additional displacement device for the formation of a high temperature chamber with varfebilem Volume and an intermediate temperature chamber with variable! Volume, which in combination as a high pressure fluid source and as a

. _ 21 -

409822/0338

Reservoir for the low pressure fluid is used. The Vuilleumier cycle is a completely closed loop and the flow path connecting these chambers includes heat storage devices such as regenerators. In the apparatus of Figure 2, the expansion chambers are housed together with a part of the intermediate \ temperature chamber in the stepped housing 180 ', / is formed from a portion 181 of larger diameter and a portion 182 of smaller diameter. The hot chamber together with the remaining part of the intermediate temperature chamber is accommodated in a housing 183. A warm (or hot) chamber 184 is arranged in this housing 183. The intermediate temperature chamber is formed from a combination of the chamber 185 arranged in the housing 183 and the chamber 186 arranged in the housing 180. These are connected to one another via a line 187 which is provided with a heat exchanger 188. The conduit 187 runs down through the head piece 189, which serves as an end of the housing 180. A piston 190, which contains a regenerator 191, can be displaced in the housing 183. If necessary, the regenerator can also be arranged outside the housing. The piston 190 is driven by a suitable drive device, such as a crank 192, to which the piston rod 193 is mechanically connected. Insofar as the operation according to this cycle requires heat (thermal energy for compression) to enter the system or into the Fluid is introduced into the hot chamber 184, a coil 194 is provided which is in thermal contact with the outer wall of the housing 183 and through which a heating fluid can be passed, · On the other hand, when the temperature of the refrigerating machine is at a level that the in the fluid 'in the chamber 184 heat to be introduced is at room temperature', "the coil can be replaced by heat transfer fins. ■ .-

In the stepped housing 180, two expansion chambers are made up of ' formed, the first chamber 195 being at an intermediate depth temperature and the second chamber 196 -on the; coldest ' Temperature of the refrigeration machine. These chambers are

.by .. oils verse, chiebebe_wegung_eInes Kolkens. _1.9Ζ_ with.,. Larger

- 22 "<-

409822/0338

Diameter and a piston 198 with a smaller diameter formed, which via a variable coupling device 199 are related to each other as they are in detail | is shown in Figs. For isolating the cold chambers Corresponding seals are provided, which are shown as O-rings at 200 and 201.

The displacer 197 is displaced by a piston rod 202, which is also attached to the crank 192. In general

the rods 193 and 202 will have a phase shift of about j 90 °, however this can vary and for any set can be determined by conditions in a simple manner.

The flow path of the fluid in this device comprises ^: (from chamber 184 to chamber 196) channels 203, regenerator 191, channels 204, chamber 185, line 187, chamber: 186, channel 215, regenerator 205 in the piston 197, j is the chamber 195, a regenerator 206 in the displacer 198 and j is the chamber 196. If the cycle itself is not part of the invention, it need not be described further. "'■ a complete description of the cycle, after the the device operates, the US-PS contains 1275 507..Es is apparent that the device according to Fig. 23, the same operational advantages as those provides according to FIGS. 1 _f 20 and 21.

The devices according to FIGS. 21 to 23 can also be formed in such a way that they have more than two cold stages and the pistons assigned to one or more stages can be connected to one another by variably coupling devices Ts.ÖTaien _t as it is with the device according to FIG. 3 is specified. In addition, such modifications as the flow path according to FIG. 5, the spring according to FIG. 7, the coupling device according to FIG. 16 and a pneumatic drive device can also be provided in the devices according to FIGS. 21 to 23.

The invention thus creates a device by which the volume of those cold chambers in a multistage cryogenic refrigeration machine, which are kept on the deeper n areas,

409822/0330

i can be adjusted by means of an optimal combination of chamber diameter and _t stroke of the piston, which forms the chambers in a housing.

409822/0338

Claims (1)

Claims in .iLow-temperature refrigeration machine with temperature gradation, in which at least two pistons of different diameters can be moved back and forth in a fluid-tight housing of graduated design to form at least two cold chambers of different diameters, which emit cold at different temperature levels and are connected to one another by a flow path for the fluid, wherein the piston with the largest diameter is connected to an externally arranged drive device, characterized in that a variable coupling device (25) is arranged between the pistons (14, 17) and is designed so that the piston (14) with the largest diameter is at least one the other piston moves over a stroke which is smaller than the stroke of the piston with the largest diameter. 2. Cryogenic refrigeration machine according to claim 1, characterized characterized in that the variable coupling device (25) has a collar attached to the engaging end of one of the pistons (26) and a lip (27) attached to the engagement end of the other piston, which lip (27) on the collar (26) for Plant can be brought. 3. Cryogenic refrigeration machine according to claim 2, characterized characterized in that the collar (118) on the piston (14) with the largest diameter and the lip (119) is formed on the other piston (17). 4. Cryogenic refrigeration machine according to claim 2, characterized characterized in that the lip (27) on the piston (14) with the largest diameter and the collar (26) on the other piston (17) is formed. 4098 22/0 33 5. Cryogenic refrigeration machine according to claim 2, characterized characterized in that a spring (116) is provided which holds the collar (26) in contact with the lip (27), when the volume of the cold chamber (16) with the largest diameter increases and while it is the maximum value maintains (Fig. 12) ·. 6. Cryogenic refrigeration machine according to claim t, characterized characterized in that the variable coupling device .. at the engagement end of the other piston (17) a contact surface in the form of a collar (26) and in the piston (14) with the largest diameter comprises a cavity (28), which forms a contact surface (.10.9) and one in the Cold chamber (16) with the largest diameter opening opening, which with an inwardly . extending lip (27) is provided for the abutment on the collar (26), this cavity (28) so designed is that a shifting movement of the other, in these Cavity engaging piston (17) is possible (Fig..4 »5,7) -. 7ο low-temperature refrigerator according to claim 1 j, characterized in that the variable coupling device has a contact surface delimiting the engagement end of the other piston (17) in the form of a lip (119), furthermore a cavity (28) formed in the piston (14) with the largest diameter _s which forms a contact surface (109) and has an opening opening into the cold chamber (16) with the largest diameter, this cavity being designed like this _? that • _g these other a displacement movement engaging therein the piston (17) IGT _{possible? s} is provided for the abutment against the lip (119) and mounted on the Kontaktfläch © _s (109) and provided with a, waistband (118) Zapf.en. (117), whereby, it is in this cavity ( 28) extends (Figο 6) ο 8. Low-temperature refrigeration machine according to claim "j, characterized in that that the variable coupling device a! • has pin {130) which is attached to the tooth section of the housing (10) is attached to the end of the cold chamber! (18) with the smallest diameter, this j The pin ends in a collar (131), and also a cavity j (135) in the other piston (123) which, through its sliding movement, forms the cold chamber (18) with the smallest diameter, this cavity forming a contact surface and has an opening which opens into the cold chamber with the smallest j diameter, which with an after! inwardly directed lip (134) is provided to rest on the collar (131) ι, and finally a spring (136), which holds the collar (131) against the lip (134), vena the ■■ volume of the cold chamber (18 ) becomes larger with the smallest diameter and while it maintains the maximum value .. (Fig. 16) ♦ 9. Cryogenic refrigeration machine according to claim 1, at the at least two pistons of different diameters in a fluid-tight housing of stepped configuration; can be moved back and forth to form at least two cold chambers of different diameters, which emit cold j at different temperature levels and are connected to one another by a flow path for the fluid which has a heat storage device arranged within these pistons, the piston with the largest diameter , is connected to an externally arranged driving means characterized in that a variable coupling means (25) is arranged between the pistons (14,17) and adapted _e that the piston (14) with ■ largest diameter of at least one of the other piston by a stroke moves «, which is smaller * than the stroke of the piston with the largest diameter. , ι. Cryogenic refrigerator according to claim 9 _t characterized in that the variable coupling means (25) 409822/0338 ^{has a collar 1} (26) attached to the engagement end of one of the pistons and a lip (27) attached to the engagement end of the other piston, which lip can be brought into contact with the collar (26). ο cryogenic refrigerator according to claim 10, characterized characterized in that the collar (118) on the piston (14) with the largest diameter and the lip (119) on the other Piston (17) is formed. 12. Cryogenic refrigeration machine according to claim 10, characterized characterized in that the lip (27) on the piston (14) with largest diameter and the collar (26) on the other piston (17) is formed. 13. Cryogenic refrigeration machine according to claim 9, characterized characterized in that the variable coupling means comprises a first cap (100) attached to the engaging end of the other piston (17) is attached and in one Bund (26) ends, being designed so that it provides fluid communication with the heat storage device (103) in that other piston (17), and a second cap (104) which is attached to the piston (14) with the largest diameter and a contact surface and one in the cold chamber. (16) with the . having the largest diameter opening opening, the is provided with an inwardly directed lip (27) for contact with the collar (26), the cavity (28) is designed so that a sliding movement of the piston (17) engaging therein is possible, and a fluid connection is provided between this cavity and the heat storage device, the inside ! of the piston (14) arranged with the largest diameter is. .. ι - "■ - I14. Cryogenic refrigerator according to claim 13, characterized in that characterized in that a spring (116) is provided, 409822/0338 which holds the collar (26) against the lip (27), j when the volume of the cold chamber (26) is the largest ! Diameter increases and while it is the maximum value maintains. j according to claim 9, '15. Low-temperature refrigeration machine for releasing cold, on ^! at least two temperature levels, characterized by: a housing (10 ') which is formed from at least two cylindrical j sections of different diameters and forms a fluid-tight, stepped space; j different by at least two pistons (14,17) Diameter, which are displaceable in the associated housing section j, whereby they by their displacement movement at least two cold chambers (16, 18) which are variable in terms of volume and have different diameters ! and varying maximum volume form, and remove the \ in these chambers achievable temperatures with decreasing chamber diameter; through a flow path for the fluid between the cold chambers (16, 18) with a heat storage device (31); by an externally arranged drive device (19) assigned to the piston (14) with the largest diameter for controlling its displacement movement in the housing and by a variable coupling device (25) which engages these pistons (14, 17) provides in such a way that the piston (64) with the largest diameter gives the other piston (65,66) such a displacement movement that at least one of these pistons executes a stroke which is smaller than the stroke of the piston with the largest diameter . 16. Cryogenic refrigeration machine according to claim 15, characterized characterized in that the variable coupling device (25) has a collar attached to the engaging end of one of the pistons (26) and one attached to the engaging end of the other piston Has lip (27) which can be brought into contact with the collar (26). 409822/0338 ^ 'S) IP F * Ρ% IA - 29 =,. 1356841 17ο Low-temperature refrigeration machine according to claim IS _9, characterized in that the collar (118) on the piston (14) with the largest diameter and the lip (119) on the other piston (17) is formed " 18 “Low-temperature cooling machine according to claim 16 _? characterized in that the lip (27) on the piston (14) is formed with the largest diameter and the collar (26) is formed on the other piston (17), 19ο cryogenic refrigerator according to claim 16 _9, characterized _in that a spring (116) is provided which keeps the collar (26) resting against the lip (27) when the volume of the cold chamber (16) with the largest diameter increases and while it maintains the maximum value = 20. Low temp he aturkältema-s chine according to claim 15? characterized in that the variable coupling means at the mating end of the other piston (17) with the largest diameter has a cavity (28) comprises a bearing surface in the form of a collar (26) and in the piston (14) _s forms a contact surface (1o9) and a in the cold chamber (16) with the largest-diameter opening which is provided with an inwardly extending lip (27) for the abutment on the collar (26) _s whereby this cavity (28) is designed _f that a Vers chi ebebew.bewegung the other _P engaging in this cavity piston (17) is possible « 21. Low temperature chiller according to claim 15 _9, characterized in that the variable coupling device has a pin (130) which is attached to the wall portion of the housing (10), which forms the end of the cold chamber ■ '(1S) with the smallest diameter ₉ whereby this pin ends in a collar (131), furthermore a cavity (135) in the other piston (123). who by his yer » 4098 2-2 / 0 Sliding movement forms the cold chamber (18) with the smallest diameter, this cavity having a contact surface and an opening which opens into the cold chamber with the smallest diameter and which opens with a direction \. inwardly directed lip (134) to bear against the collar (131); is provided, and finally a spring (136) which keeps the collar (131) against the lip (134) when the volume of the cold chamber (18) with the smallest diameter increases, and while it maintains the maximum value. . 22. Low-temperature refrigeration machine according to claim 15 »characterized in that j characterized »that the heat storage devices within- J half of the piston are arranged and the variable coupling device i has a first cap (100) which is attached to the engaging end of the other piston (17) and in! a collar (26) 'ends, being formed so that; You have a flui & connection with the heat storage device. \ (103) in this other piston (1?) Results, and a second J cap (104), which on the piston (14) with the largest diameter. ! is attached and has a contact surface and an opening which opens into the cold chamber (16) with the largest diameter and is provided with an inwardly directed lip (27) for contact with the collar (26), v / whether the | Cavity (28) is designed so that a displacement movement of the piston (17) engaging therein is possible, and a fluid connection is provided between this cavity and the heat storage device, which is arranged within the piston (14) with its largest diameter. 23. Cryogenic refrigerator according to claim 8, characterized characterized in that the piston with the largest diameter during its verse chi ebebewigung forms an additional chamber with variable volume, which via this flow path is in fluid connection with the cold chambers » Characterized in 124. cryogenic refrigerator of Claim 15 »j that a Hochdruckfluiäquelle (40) and a low pressure reservoir (41) provided sina _o 409822 / 033® ο Low-temperature refrigeration machine according to claim 24, characterized in that the high-pressure fluid source. and the low-pressure fluid reservoir is arranged outside the housing and provided with slide-controlled lines (35 * 37) for connection between these and the cold chambers. 26. Cryogenic refrigeration machine. according to claim 25, characterized characterized in that the high pressure fluid source and the low pressure fluid reservoir are provided by a compressor (156) ' are educated » j ■. ^l 27. Cryogenic refrigeration machine according to claim. 24, characterized in S that in the housing a piston is slidably .zusätzlicher j to form a compression chamber with variable volume j ₅ which serves as a high pressure fluid source and a low-pressure fluid reservoir. 28. Cryogenic refrigeration machine according to claim 24, characterized : 'characterized in that displacer is arranged in the housing j, which form high-temperature and intermediate-temperature chambers of variable volume, which over heat storage devices are in "fluid connection, this High temperature and intermediate temperature chambers (184, 185) together as a high pressure fluid source and as a low pressure fluid reservoir to serve. 29. Cryogenic refrigeration machine according to claim 15, characterized characterized in that the housing is formed from three cylindrical sections in which three pistons are displaceable are, wherein at least one of the other pistons executes a stroke which is smaller than the stroke of the piston with the largest diameter. 30. Cryogenic refrigerator according to claim 15, characterized characterized in that the housing consists of three cylindrical Sections is formed and the in the section with 409822/033 8 the mean diameter of the displaceable piston over the variable coupling device is connected to the piston with the largest diameter, while in the Housing section with the smallest diameter displaceable piston via the variable coupling device with the piston. with the mean diameter "in connection ^: stands so that the stroke of the piston with the mean diameter is smaller than that of the piston with the largest ■ Diameter and stroke of the piston with the smallest Diameter is smaller than that of the piston, with the middle one Diameter. 31. Cryogenic refrigerator according to claim 29, characterized characterized in that an external high pressure fluid source, j an external low pressure fluid reservoir and for connection slide-controlled lines are provided between these and the chambers. 32. Cryogenic refrigeration machine according to claim 15, characterized j characterized in that the variable coupling device a stroke adjustment device (99) is assigned to control the stroke path of the other piston or pistons. 33. Cryogenic refrigeration machine with temperature graduation for the liquefaction of gas, characterized by a housing made of three cylindrical sections of different diameters to form a fluid-tight envelope in a stepped construction by three pistons of different diameters, which are displaceable in the associated housing sections and due to their displacement movement, three cold chambers with different diameters and variable in terms of volume J form different maximum volumes, with those in these • Decrease chambers of attainable temperatures with decreasing chamber diameter; through a flow path for the fluid between the cold chambers with heat storage devices; 409822/033 8 through a first source of high pressure fluid; through a first low pressure fluid reservoir through one of the piston with the largest diameter j associated, external drive device for controlling its displacement movement in the housing; by a variable coupling device for the engagement between these pistons, which is designed so that the piston with the largest diameter is the other two pistons moves, with at least "one of these a stroke which is smaller than that of the piston with the largest diameter) ■ by a respective heat station assigned to each cold chamber for the discharge of cold via contact-free heat exchange with the fluid in these cold chambers at three decreasing temperature levels;
! through a second high pressure fluid source outside the housing through a second low pressure fluid reservoir outside the Housing; - - • by a liquefaction device for expanding and j j for at least partially liquefying the high-pressure fluid j from this second source of high pressure fluid; .. '", .. through a container to hold the liquefied fluid, which forms a source of cold low pressure fluid and through heat exchangers with these heat stations the three temperature levels for contact-free heat exchange between that from this second source of high pressure fluid fluid supplied to the liquefaction device and that from the container to the second low pressure fluid reservoir flowing cold low pressure fluid. 34oTieftemperaturkältemaschine _r characterized-in according to claim 33, that the first and second Hqchdruckfluidquelle and the first and second low-pressure fluid reservoir are each combined into a slide and controlled. Lines for connection between the. combined high pressure fluid source and the combined • low pressure fluid reservoir and the flow path are provided. 409822/0338 -.-. / " 35. Cryogenic refrigerator according to claim characterized in that the low pressure fluid reservoir and the high pressure fluid source are combined in a compressor. 36. Cryogenic refrigeration machine according to claim 33 » characterized in that an additional piston for forming a compression chamber in the housing is displaceable with a variable volume, the first high pressure fluid source and the first low pressure fluid reservoir serves. 37. Cryogenic refrigeration machine according to claim 33, characterized in that a displacer is arranged in the housing, the one high temperature and one Forms intermediate temperature chamber with variable volume, which are in fluid communication via heat storage devices, these high-temperature and intermediate-temperature chambers together serve as a first high pressure fluid source and a first low pressure fluid reservoir. 40S822 / 0338 Empty se 11 e