DE20207013U1 - Device for closing a pot-shaped digestion container - Google Patents

Description

MLS GmbH
P26051DE

Device for closing a pot-shaped digestion container

The invention relates to a device according to the preamble of claim 1 or 7.

In order to carry out an analysis of substances, it is known to heat one or more substances, e.g. a solid or liquid sample material, in a digestion vessel, which in most digestion cases creates an overpressure in the digestion vessel, which in turn promotes the digestion of the sample material or the like.

A device of the type specified in the preamble of claim 1 and for carrying out this measure is described in EP 0 830 891 A1. In this generic design, an elastic pressure medium acting between a screw part and a pressure stamp is formed by a stack of metal disc springs arranged one above the other, the pressure stamp being formed as a U-shaped component in which a dome-shaped cage part is arranged, which consists of metal and forms a Faraday cage for the disc springs. This device is multi-part and of a large, in particular high, construction.

A device for closing a pot-shaped digestion container according to the preamble of claim 7 is described in GB 2 184 040 A. In this known device, the pressure stamp, the screw part and the elastic pressure medium arranged between them are accommodated in a hat-shaped screw lid of a pot-shaped support container in which a receiving container is suitably inserted, against whose lid the pressure stamp acts. The screw part is guided vertically displaceably with a pressure piece in a vertical guide hole in the screw lid and is designed as a nut which is screwed onto a pressure piece extending coaxially upwards from the pressure stamp in a threaded shaft which passes through a guide hole. In the ring wall of the hat-shaped screw lid, when screwed on, an inner ring groove is arranged at the height of the upper edge of the support container, from which a vent channel extends radially outwards through the ring wall. The known design is multi-part, of large construction, complex to manufacture and time-consuming to handle. There is also a risk that the pressure piece and the nut will move apart due to contamination, for example, resulting in different pressure ranges when opening and closing the lid of the receiving container.

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The invention is based on the object of simplifying a device of the types specified at the outset and designing it in such a way that a small or low construction is achieved. In addition, the device is to be improved in terms of its function. In addition, the aim is to reduce the number of individual parts of the device and the material required for them.

This object is solved by the features of claim 1 or 7. Advantageous developments of the invention are described in the subclaims.

In the device according to the invention according to claim 1, the pressure stamp and the screw part overlap each other in a sleeve-like manner with at least one ring wall, which can be part of the pressure stamp, which preferably extends upwards in one piece from the latter and overlaps the screw part in a sleeve-like manner, or which can be part of the screw part, which preferably extends downwards in one piece from the latter and overlaps the pressure stamp in a sleeve-like manner. It is also possible for two peripheral walls to be provided, of which one ring wall extends upwards from the pressure stamp and the other ring wall extends downwards from the screw part and the ring walls overlap each other in a sleeve-like manner. This not only provides guidance and/or radial support for the pressure stamp, but the interior space between the pressure stamp and the screw part that accommodates the elastic pressure medium is closed by the at least one ring wall, so that neither contaminants from the receiving space of the receiving container in the event of an overpressure reaction that lifts the lid of the receiving container nor other contaminants from the environment of the device can get into the interior space for the elastic pressure medium. This also protects the interior from aggressive treatment or decomposition chemicals, which protects the movement function of the device and ensures a long service life. A thread guide is a forced guide in both axial directions of movement, which leads to a safe adjustment of the screw part even if there is a certain stiffness in the guide.

The seal between the pressure stamp and the screw part can be improved by arranging a seal between the sleeve-like cooperating guide surfaces, preferably a ring seal, which can be an O-ring, for example, which can be inserted in an outer ring groove of the overlapping part or in an inner ring groove of the overlapping part.

Within the scope of the invention, there are many possibilities for supporting the screw part on an abutment. Such an abutment can be formed, for example, by a supported disk that covers a stand for the digestion container in a space that can be exposed to microwaves. If such a disk is open on all sides, it can also be used to cover several stands for digestion containers that are distributed around the circumference with the device. In this case, the disk can be a turntable in a manner known per se, which is mounted so that it can rotate with the stands in the microwave space.

The abutment can also be formed by the ceiling wall of a pressure-absorbing body that delimits a stand for a digestion vessel on both sides, from above and below. In this design, the digestion vessel can be placed on the stand with the device from one side and removed again.

It is also possible according to claim 7 to form the abutment on the outer surface of the digestion tank or to support it thereon. For this purpose, the screw part can be formed by the top wall of a cap, the ring wall of which can be connected to the digestion tank, e.g. in its free edge area, e.g. by screws. In this case, it is particularly advantageous if a screw ring with an external thread is placed on the outer surface of the digestion tank and is supported on it, preferably on the underside of a flange in the edge area of the digestion tank, so that the flange absorbs the support forces of the device and ensures that the screw ring is positioned by contact. This design is particularly characterized by a small design that takes up little installation space, is handy, uses little material and is also lightweight.

It is possible and advantageous in all designs to arrange a marking or a scale between the screw part or attachments thereof and the abutment so that the screw part can be pre-set in stages or continuously with respect to the elastic closing force of the pressure medium so that a certain opening pressure is reached, when this pressure is exceeded in the digestion chamber of the digestion vessel, the lid of the digestion vessel automatically lifts off and thus opens. This allows the operator to predetermine the desired maximum internal pressure in the receiving chamber of the receiving vessel, taking into account the substance or substances to be treated.

If, in a device of the present type, the lid of the digestion vessel forms a valve body of a valve which opens at a predetermined internal vessel pressure due to the flexibility of the elastic pressure medium, a

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A relatively large pressure surface is available on the inside of the lid, and therefore a relatively large pre-tensioning force is required to hold the lid in its closed position on the digestion vessel. Consequently, a relatively large amount of force is required to change the pre-tensioning force and thereby set the internal pressure value above which the lid should open automatically. Another disadvantage is that with such an overpressure opening of the lid, the actual opening and blow-off point is undefined and can extend over an undefined area of the circumference or over the entire circumference.

The invention is further based on the object of providing a device according to the preamble of claim 18, in which the decomposition vessel is to be opened and can be adjusted with little effort. It is also intended to design the device in such a way that when the decomposition vessel is vented when the internal pressure exceeds a certain value, the venting takes place in a targeted manner at a certain point.

This object is solved by the features of claim 18.

Advantageous developments of the invention are described in the associated subclaims.

In the device according to the invention according to claim 18, the lid has an outlet channel passing through it, which is closed by a valve which opens automatically when the internal pressure in the digestion container exceeds a certain value.

In this design, there is a special valve in the area of the lid that opens automatically when the pressure inside the container exceeds a certain pressure value, with the lid remaining in its closed position. In this design, the size of the opening of the digestion container is not relevant, but rather the size of the outlet channel, which is significantly smaller than the opening size of the digestion container or the size of the lid. Therefore, a significantly lower preload force is required to close the valve, and changes to this preload force can be carried out in a handling-friendly manner with a relatively low expenditure of force, so that the handling comfort of the device according to the invention is significantly improved.

Furthermore, in the embodiment according to the invention according to claim 18, the blow-off point is limited to the mouth opening of the outlet channel.

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Since sample material can also escape during the blow-off process and this can lead to contamination, measures to prevent or eliminate contamination can be arranged or carried out more easily and specifically with this design.
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Further developments of the invention lead to simple, small and functional designs, and they serve to prevent contamination of the valve mechanism and to enable targeted and easy-to-use adjustment of different pressure values at which the valve opens.
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Advantageous embodiments of the invention are explained in more detail below using several embodiments and drawings. It shows

Fig. 1 shows a container arrangement with a device according to the invention for

Closing a digestion vessel in vertical section;

Fig. 2 the detail marked X in Fig. 1 in an enlarged

Depiction;

Fig. 3 shows a modified container arrangement with a likewise modified

Device for closing a digestion container in vertical section;

Fig. 4 shows a container arrangement with a modified

Device for closing a digestion vessel in the vertical

Cut.

A pot-shaped digestion vessel 1 with a hollow cylindrical and, for example, relatively thin peripheral wall la and a flat bottom wall 1b is surrounded by a hollow cylindrical support shell 2 and supported radially outwards, which can extend up to a flange 1c at the upper edge of the peripheral wall la, so that the flange 1c rests on the upper end face of the support shell 2.

The top opening of the digestion container 1 is to be closed and opened by a flat and stepped cylindrical lid 3 (seat lid), which in the embodiment with a lower cylindrical lid attachment 3a with little play in the digestion container 1 and is preferably sealed by a ring seal 4. This can be formed by an O-ring 4a, the

in an annular groove in the outer surface of the cover attachment 3a. The cover 3 therefore rests with its shoulder surface 3b on the flange 1c.

The device designated as a whole with 5 for closing the digestion container 1 even when there is excess pressure in its digestion interior Id consists mainly of 3 parts, namely a pressure stamp 6, a screw part 7 arranged at least partially above it and an elastic pressure medium 8 which is arranged between an upwardly directed support surface 6a on the pressure stamp 6 and a downwardly directed support surface 7a on the screw part 7 and is prestressed with a certain compression force during functional operation. In the exemplary embodiment, the pressure medium 8 consists of several disc springs stacked on top of one another in opposite directions. The screw part 7 has an external thread 7b at least in its upper region, with which it is screwed into a threaded hole 9a of an abutment 9 as a screw part. In order to rotate the screw part 7, a rotary engagement element 11 for a rotary tool that can be brought into a positively locking rotary connection therewith is arranged on its upper side. In the embodiment, the rotary engagement element 11 is formed by a non-circular plug-in recess.

In order to cover the space 12 occupied by the pressure medium and thus protect it from contamination, an annular wall 7c is provided which surrounds the space 12 and by means of which the pressure stamp 6 and/or the screw part 7 are at least partially overlapped in a sleeve-like manner. In the exemplary embodiment, the preferably hollow-cylindrical annular wall 7c extends in one piece from the screw part 7 downwards, at least partially overlapping the preferably cylindrical peripheral surface of the pressure stamp 6 with play for movement, whereby the space 12 is inaccessible from the side.

The vertical overlap dimension a can be dimensioned so large that a guiding function between the pressure stamp 6 and the screw part 7 and/or a ring seal 13 is ensured during the telescoping of the device 5, which will be described later.

Preferably, a sealing ring 13a is arranged in the overlap gap, e.g. an O-ring, which sits in an annular groove in the outer surface of the pressure stamp 6 and is covered by the inner surface of the ring wall 7c in every telescoping position. In the present embodiment, the vertically extending maximum telescoping dimension b is determined by the distance of the ring wall 7c from the cover 3. In a design of the pressure stamp 6 with a flange 6b, as shown in outline, the maximum telescoping dimension b is determined by the distance from the flange 6a. The flange 6b allows the pressure surface of the pressure stamp 6 acting against the cover 3 to be increased and the surface pressure effective during functional operation to be reduced.

The pressure medium 8 or the spring disks can be centered by the inner surface of the ring wall 7c. However, in order to avoid the frictional wear that occurs between them during telescoping, the preferably ring-shaped pressure medium 8 is centered internally by a centering bolt 6c with little play, which in the embodiment extends in one piece from the pressure stamp 6 upwards and can dip into a guide hole 7d between the support surface 7a and the rotary engagement element 11 or end shortly before it, thereby creating an additional, but not absolutely necessary, guide for the pressure stamp 6.

A through hole 14 is preferably arranged coaxially in the pressure stamp 6, which can be lined, for example, by an annular wall 15, which can have a flange at its lower end with which it is arranged countersunk in a recess in the pressure surface. The annular wall 15 can be pressed into the pressure stamp 6 with a press fit for its axial fastening.

The hole 14 can be used to accommodate functional elements, such as sensor elements, which pass through the screw part 7 and are functionally connected to the associated control or regulating devices. For example, a temperature sensor can be provided which is inserted into the hole 14. A pressure measuring element can also be inserted into the hole 14, the vertical position or change in position of which when the cover 3 is lifted off serves as an indicator for the level of the internal pressure prevailing in the digestion chamber Id during functional operation.

In the embodiment according to Fig. 1, the abutment 9 is formed by the top wall 16a of a support housing 16, which can be box-shaped with a bottom wall 16b and two side walls 16c and forms a front-open or horizontally continuous storage space 17 for the digestion container 1, into which the latter can be inserted and removed again from the relevant side. In the adjusted state, the digestion container 1 rests with its bottom wall 1b, which is flat in the embodiment, on the bottom wall 16b of the support housing 16, whereby the former bottom wall 1b is supported against the internal pressure. An intermediate disk 18 can be arranged between the bottom walls 1b and 16b, which is preferably made of heat-insulating material, e.g. plastic, in order to reduce the heat dissipation from the digestion container 1.

The ring wall 7c extending downwards from the screw part 7 enables, due to the resulting relatively large length, a large vertical adjustment range for the screw part 7 and thus its adaptation to different heights of digestion vessels 1, if the external thread 7b extends at least as far as the

lower end region of the ring wall 7c or, for example, over its entire vertical length.

In order to prevent the pressure stamp 6 from falling out of its overlapping position with the screw part 7 when there is no digestion container 1 under the device 5, a limiting device 21 is provided between the pressure stamp 6 and the screw part 7 or the ring wall 7c, which limits the maximum extension movement of the pressure stamp 6 and in the embodiment is formed by a stop device with a stop element 22a in the lower end region of the ring wall 7c. The counter stop element 22b is preferably formed by the sealing ring 13a, which projects radially slightly beyond the outer surface of the pressure stamp 6 and can thus form the counter stop element 22b without the need for a special counter stop element. The sealing ring 13a thus fulfills a sealing and a stop function. The stop element 21 is formed by an inner annular bead on the inner outer surface of the ring wall 7c. The diameter of the annular bead is larger than the diameter of the pressure stamp 6, taking into account a small amount of movement or sliding play, which ensures that it can be moved in the annular bead. The inner diameter dl of the annular bead is slightly smaller than the remaining inner diameter d2 of the ring wall 7c, which allows the inner bead to be formed. The inner diameter d2 is only large enough for the sealing ring 13a to form an elastic seal against the inner surface 7e of the ring wall 7c. In the exemplary embodiment, the outer flank of the stop element 22 or annular bead is formed by an inclined or rounded introduction surface 23. The inner flank 24 is a stepped surface that preferably extends approximately at right angles to the central axis of the pressure stamp 6. In the exemplary embodiment, the inner annular bead is pointed in cross-section, resulting in a pointed ring edge. As a result, the sealing ring 13a is sheared off when the pressure stamp 6 is forcibly pulled out of its socket connection and, taking into account the damage to the sealing ring 13a, dismantling protection is created.

In the embodiment according to Fig. 3, in which identical or comparable parts are provided with identical reference numerals, the screw part 7 with its ring wall 7c is designed to be so large that it covers the digestion container 1 in the form of a cap at least in its upper edge region and is screwed to it, so that the peripheral wall 1a or the flange 1c or a possibly present support casing 2, to which the ring wall 7c can be screwed, forms the abutment 9. In the embodiment, a support ring 25 is placed on the digestion container 1, preferably in the upper region of the digestion container 1, in particular arranged in contact with the flange 1c and with the outer casing surface of the

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Decomposition vessel 1, ζ. B. by pressing or gluing. Such a connection ensures that the abutment forces are introduced into the decomposition vessel 1. If the support ring 25 rests on the flange Ic, a connection to the outer shell surface can be dispensed with, since the flange Ic absorbs the abutment forces. But even in this case it is advantageous to hold the support ring 25 captive on the decomposition vessel 1, e.g. by gluing or pressing.

The screw connection between the screw part 7 and the support ring 25 preferably has an internal thread 7f in the end region of the ring wall 7c and a matching external thread on the support ring 25.

In both of the above-described embodiments, the pressure stamp 6 can form the lid 3, as shown in Fig. 3. In the embodiment according to Fig. 1, the cross sections of the pressure stamp 6 and the screw part 7 would have to be enlarged accordingly so that the pressure stamp 6 can form the lid 3. In addition, the hole 14 would have to end at a distance from the end of the pressure stamp 6 facing the digestion container 1.

In all embodiments, it is also possible to form the pressure stamp in a U-shaped cross section according to Fig. 3 and thus to provide it with a peripheral wall 6d which, due to its axial length, ensures that the pressure stamp 6 is guided in a way that prevents it from tipping over and can also ensure adequate sealing. It is also advantageous to arrange one or more grooves 6e in the outer surface of the peripheral wall 6d which are axially spaced from one another, which both improve the sealing and, taking into account different thermal expansions, avoid harmful stresses in the fit, especially when the material of the pressure stamp is relatively soft or flexible, especially at higher decomposition temperatures.

In the embodiment according to Fig. 3, the elastic pressure medium 8 is formed by a helical spring which is supported on the top wall of the screw part 7 and acts on the pressure stamp 6, here in the recess base.

In the embodiment according to Fig. 3, a centering bolt 6c can also be provided, which is preferably also circular in cross section and can be guided lengthwise or vertically with play in the guide hole 7d in the top wall of the cap-shaped screw part 7. The centering bolt 6c preferably has a flange at its lower end to reduce the surface pressure, on which the pressure medium 8 can rest.

In all embodiments, it is advantageous to apply a marking between the screw part 7 and a part positioned on the digestion container 1 or on the lid 3 or on the pressure stamp 6, which allows the axial position of the screw part 7 to be recognized with respect to the positioned part and preferably enables a defined pre-setting of the screw part 7. The marking can be formed, for example, by a scale and an index, each of which is located on one of the two comparative parts. In the embodiment according to Fig. 1, the marking 27 can be arranged, for example, on the upper sides of the screw part 7 and the abutment 9, preferably near or on the thread groove of the screw lock, e.g. as a ring scale on the top wall 16a and as an index on the screw part 7.

In the embodiment according to Fig. 3, the marking 27 can be formed, for example, by the front end of the centering bolt 6c and the lower or upper edge of the guide hole 7d. It is also possible to apply the markings or scale lines to the inner wall surface of the guide hole at axial distances from one another, which, with the free end of the centering bolt 6c, enable the position of the centering bolt 6c and thus also the opening or closing position of the pressure stamp 6 and, if applicable, also the cover to be recognized or read.

1, the digestion container 1 is made of a corrosion-resistant material, in particular plastic and preferably polytetrafluoroethylene (PTFE). The other parts of the digestion container 1, including the support housing 16, are preferably made of microwave-permeable material, preferably plastic. This can also apply to the device 5. In the exemplary embodiment, the spring or spring elements forming the elastic pressure medium 8 are made of metal, in particular spring steel or stainless steel. The screw part 7 can also be made of metal, e.g. stainless steel, where it acts as a Faraday cage with regard to the spring. The function is improved if the cage has a polished surface and its edges are rounded. In addition, it is advantageous to dimension the dimensions of the cage, i.e. its diameter and its axial length, preferably between a quarter and a whole wavelength of the microwave radiation used. In addition, the surface of the metal cage can be coated with a material such as e.g. B. PTFE, which is resistant to aggressive chemicals, to prevent the metal surface from being attacked by the chemicals.

For a digestion process, a sample material is placed in the digestion container 1 and the digestion container 1 is closed with the device 5. The screw part 7 is screwed in (Fig. 1) or unscrewed (Fig. 3) so far that the

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elastic pressure medium 8 applies a closing force that corresponds to a certain internal pressure. If the internal pressure rises above a certain value or the set value during functional operation, the cover 3 or the pressure stamp 6 opens automatically, whereby the pressure medium 8 gives way and the internal pressure can escape. In this case, the device 5 functions like a pressure relief valve, whereby the opening pressure can be adjusted by screwing in the screw part 7.

The embodiment according to Fig. 3, in which identical or comparable parts are provided with identical reference numerals, differs from the previously described embodiment with regard to several configurations.

On the one hand, the abutment 9 is not part of a support housing 16 that accommodates the entire digestion container 1, but rather a small cap-shaped support housing 22, which also directs the support forces into the digestion container 1, but only extends over the upper region of the digestion container 1, is supported directly or indirectly on this upper region and thus directs the support forces into this region of the digestion container 1. The connection directly or indirectly to the upper region of the digestion container 1 is made by a screw connection. A radial blow-off opening 7g is provided in the ring wall 7c above the flange 1c or the support ring 25. The bottom wall 1b of the preferably cylindrical receiving container 1 is preferably hemispherical, which ensures that the wall is evenly stressed.

In the embodiment according to Fig. 4, in which identical or comparable parts are provided with the same reference numerals, the digestion container 1 (apart from the lid 3) and the support housing 16 can be essentially identical or basically identical. The essential differences are as follows.

On the one hand, the screw part 7 forming a closure part is designed to be so long that it reaches up to the lid 3 and can thus be tensioned against the lid 3, whereby the digestion container 1 can be tightly closed and the lid 3 is rigidly closed.

On the other hand, an outlet channel 31 is arranged in the cover 3, which is closed by a valve 32, the valve 32 opening automatically when the internal pressure in the digestion vessel 1 exceeds a predetermined value. The outlet channel 31 can run at an angle, the first outlet channel section 31a extending from the interior Id preferably extending coaxially in the cover 3 and merging into a laterally extending outlet channel section 31b in the upper region of the cover 3. A valve body 33 in a

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Pressure stamp 6 of the previous embodiment. The valve body 33, which is cylindrical for example, closes the outlet channel 31 on the underside, whereby in the embodiment it is enclosed in a channel enlargement 31c on the top of the cover 3 with a rectangular step surface 31d for example, which forms a stop for a downward movement of the valve body 33. The lateral outlet channel section 31b branches off from the channel extension 31c above the step surface 31d. A pin 33a adapted to the outlet channel section 31a with play can protrude from the underside of the valve body 33, which closes the outlet channel section 31a with little play. The length c of the pin 33a is smaller than the length e of the channel enlargement 31c.

The valve body 33 extends downwards from a valve body base 33b with an enlarged cross-section, which is adapted with play to the inner cross-sectional shape and size of the screw part 7, which is hollow and cylindrical in this area, and is thus guided vertically displaceably therein. A bolt 33c can extend concentrically upwards from the valve body base 33b, which can, for example, be formed as one piece onto the valve body base 33b and penetrates an upper end wall 7f of the screw part 7 in a hole 34 and can close off or protrude at the top. Between the end wall 7f and the valve body base 33b there is a spring 35 surrounding the bolt 33c, e.g. a helical spring, which is supported on the end wall 7f and preloads the closure part, designated as a whole by 36, downwards. The upper end of the bolt 33c can form with the upper end face of the screw part 7 an indicator for the pressure occurring in the movement range of the length c or for the opening pressure.

The closure part 36 is preferably formed in two parts with the valve body 33 and is detachably connected to the latter by a screw connection. In the embodiment, a threaded pin 33d projects downwards from the valve body base 33b, onto which the valve body 33 is screwed with a threaded hole 33e and is thus held detachably and replaceably. For the purpose of adaptation to different covers 3, several different valve bodies 33 adapted to the respective associated cover 3 can be provided, which can be connected to the valve body base 33b by exchanging them.

A stop 37 can be arranged at the lower end of the screw part 7 to limit the downward movement of the closure part 36. In the embodiment, a flange disk 38 is preferably detachably attached to the lower end of the screw part 7, which has a coaxial hole 39 in which the valve body 33 passes through the flange disk 38, e.g. can also be guided in it, and projects downwards beyond the flange disk 38.

For a digestion process, the filled digestion container 1 is placed under the valve body 33, and the screw part 7 is manually screwed against the lid 3 using a turning tool 41, which can be positively connected to the upper end of the screw part 7 using a non-circular tenon connection or two tenon connections 41a, 41b, as a result of which the digestion container 1 is rigidly closed with axial tension. The screw part 7 rests on the lid 3 with the flange disk 38, as a result of which the surface pressure is low due to the relatively large surface area of the flange disk 38. When the screw part 7 moves against the lid 3, the valve body 33 strikes the valve seat 33a and the valve body base 33b or the closure part 36 is preloaded against the spring 35 by the preload path V, the spring 35 having a specific preload, e.g. B. 200 N/mm, against the valve seat. In the embodiment, the first outlet channel section 33a has a diameter of approximately 8 mm.

In the embodiment, the valve body 33 is made of a corrosion-resistant material, e.g. ceramic or plastic, preferably PTFE. The valve body base 33b can be made of corrosion-resistant steel or ceramic, for example. The screw part 7 and the flange disk 38 are preferably made of corrosion-resistant metal, in particular stainless steel. This also applies to the spring 35, which can be made of spring steel, for example.

In order to protect the interior of the screw part 7 from contamination, an annular seal 42 is arranged between the valve body base 33b and the wall of the screw part 7, preferably with a sealing ring 42a, which sits in an annular groove of one component, in particular in the valve body base 33b, and cooperates tightly with the opposite wall of the other component. Such an annular seal 42 can also be provided between the flange disk 38 and the valve body 33.

For a digestion operation, the container arrangement is placed in a microwave oven and exposed to microwaves. If the internal pressure in the digestion container 1 exceeds a predetermined value due to internal heating and possibly also a reaction of the substance in the digestion container, the valve body 33 automatically lifts off the valve seat, whereby the outlet channel 31 is opened and the internal pressure is limited by blowing off through the outlet channel 31.

In all embodiments it is advantageous to design the device 5 or the valve 32 so that it is adjustable that the cover 3 or the valve 32 opens at different thicknesses in the opening area. This allows the opening pressure and

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thus the pressure effective when treating or breaking down the material can be changed and adapted to a given requirement. This can be achieved, for example, by assigning several elastic pressure means 8 or several springs 35 with different pressure forces, which can be used optionally by interchanging. This allows the device 5 or the valve 32 to be adapted to different opening pressures.

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Claims (28)

1. Device ( 5 ) for closing a pot-shaped digestion container ( 1 ), the opening of which is covered by a lid ( 3 ), with - a printing stamp ( 6 ), - a screw part ( 7 ) arranged coaxially to the pressure stamp ( 6 ), - and an elastic pressure means ( 8 ) arranged between the pressure stamp ( 6 ) and the screw part ( 7 ), characterized in that the screw part ( 7 ) and the pressure stamp ( 6 ) overlap each other in the form of a sleeve. 2. Device according to claim 1, characterized in that an annular wall ( 7 c) extending from the screw part ( 7 ) overlaps the pressure stamp ( 6 ) and is preferably connected in one piece to the screw part ( 7 ). 3. Device according to claim 1 or 2, characterized in that an annular seal ( 13 ) is arranged between the annular wall ( 7 c) and the pressure stamp ( 6 ). 4. Device according to claim 3, characterized in that the ring seal ( 13 ) is formed by a sealing ring ( 13a ) made of elastic material, which sits in an annular groove in the inner surface of the ring wall ( 7c ) or in the outer surface of the pressure stamp ( 6 ). 5. Device according to one of the preceding claims, characterized in that the screw part ( 7 ) has an external thread ( 7b ). 6. Device according to claim 5, characterized in that the screw part ( 7 ) is screwed or can be screwed into a stationary supported abutment ( 9 ), wherein a stand for the digestion container ( 1 ) is located under the screw part ( 7 ) and the pressure stamp ( 6 ), and wherein preferably the abutment ( 9 ) is formed by the top wall ( 16a ) of a box-shaped housing ( 16 ) having the stand. 7. Device ( 5 ) for closing a pot-shaped digestion container ( 1 ), the opening of which is covered by a lid ( 3 ), with - a printing stamp ( 6 ), - a screw part ( 7 ) which overlaps the pressure stamp ( 6 ) in the form of a cap and which has a screw thread in its lower edge region with which it can be screwed to an abutment ( 9 ) which surrounds the decomposition container ( 1 ), characterized in that the abutment ( 9 ) is formed by a support ring ( 25 ) which is fixed to the circumference of the digestion container ( 1 ). 8. Device according to claim 7, characterized in that the digestion container ( 1 ) has a flange ( 1c ) on its edge and the support ring ( 25 ) is fastened to the outer surface of the digestion container ( 1 ) and/or engages under the flange ( 1c ) and/or is formed on the flange ( 1c ). 9. Device according to one of the preceding claims, characterized in that the pressure stamp ( 6 ) is guided in an axially sliding manner with a cylindrical sliding surface on a hollow cylindrical sliding surface of the screw part ( 7 ). 10. Device according to claim 9, characterized in that one or more annular grooves ( 6e) having an axial distance from one another are arranged in the cylindrical sliding surface of the pressure stamp (6 ) . 11. Device according to one of the preceding claims, characterized in that the pressure stamp ( 6 ) has a U-shaped cross-sectional shape and the elastic pressure means ( 8 ) is arranged in the recess formed by the U-shaped cross-sectional shape. 12. Device according to one of the preceding claims, characterized in that the elastic pressure means ( 8 ) is formed by one or more disc springs stacked on top of one another or a coil spring. 13. Device according to one of the preceding claims, characterized in that a preferably coaxial hole ( 14 ) is arranged in the pressure stamp ( 6 ). 14. Device according to one of the preceding claims, characterized in that the screw part ( 7 ) has in its upper region a guide section ( 7d ) for an extension ( 6c ) extending in one piece from the pressure stamp ( 6 ) or arranged thereon. 15. Device according to one of the preceding claims, characterized in that the screw part ( 7 ) has a rotary engagement element at its upper end, e.g. a non-circular recess ( 11 ) open on the upper side for a rotary tool. 16. Device according to one of the preceding claims, characterized in that the pressure stamp ( 6 ) forms the cover ( 3 ). 17. Device according to one of the preceding claims, characterized in that a position marking, e.g. a scale and an index, is arranged between the screw part ( 7 ) and the abutment ( 9 ). 18. Device ( 5 ) for closing a pot-shaped digestion container ( 1 ), the opening of which can be closed by a lid ( 3 ) which can preferably be clamped against the lid ( 3 ) by means of a closure part ( 7 ), characterized in that the lid ( 3 ) has an outlet channel ( 31 ) passing through it, which is closed by a valve ( 32 ) which automatically opens the outlet channel ( 31 ) when the internal pressure in the digestion container ( 1 ) exceeds a certain value. 19. Device according to claim 18, characterized in that the outlet channel ( 31 ) runs axially, in particular coaxially, from the inside to the outside and the valve ( 32 ) has a valve body ( 33 ) which is larger than the outlet channel ( 31 ) and is prestressed by a spring ( 35 ) against an edge of the outlet channel ( 31 ). 20. Device according to claim 19, characterized in that the edge is formed by the step surface ( 31 d) of a channel extension ( 31 c) of the outlet channel ( 31 a). 21. Device according to claim 20, characterized in that an outlet channel section ( 31b ) branches off in the cover ( 3 ) above the step surface ( 31d ). 22. Device according to one of claims 18 to 21, characterized in that the closure part is a screw part ( 7 ) which is screwed into an abutment ( 9 ) arranged above the digestion container ( 1 ) and can be screwed against the lid ( 3 ). 23. Device according to claim 22, characterized in that the screw part ( 7 ) forms a guide for the valve body ( 33 ). 24. Device according to claim 23, characterized in that the screw part ( 7 ) is a sleeve into which the valve body ( 33 ) extends. 25. Device according to claim 24, characterized in that the spring ( 35 ) is arranged in the sleeve. 26. Device according to claim 24 or 25, characterized in that a stop ( 37 ) limiting the extension movement of the valve body ( 33 ) is arranged on the lower edge of the sleeve, which stop is preferably formed by a flange ( 39 ) preferably detachably fastened to the lower edge of the sleeve. 27. Device according to one of claims 19 to 26, characterized in that the valve body ( 33 ) is detachably connected to a valve body base ( 33b ), preferably by a screw connection. 28. Device according to one of the preceding claims 19 to 27, characterized in that a valve body pin ( 33a ) projects downwards from the valve body ( 33 ) and fits into the outlet channel ( 31a ) with little play.