Pressure fitting for material flows, method for operating pressure fittings, and use

Abstract

The invention relates to a pressure fitting for material flows, having a main part with a pressure-reducing unit arranged in the interior of the main part and being characterized in that a.) there is a material discontinuity between the main part and the pressure-reducing unit, and / or b.) there is a material discontinuity between a wall part and the main part arranged within the wall part.

Description

[0001] Pressure valve for material flows, method for operating pressure valves and use

[0002] The invention relates to a pressure valve for material flows, a method for operating pressure valves and a use.

[0003] Piping systems are used in many industries, for example, in chemical plants, refineries, and power plants, where pumps, equipment, and pressure valves are used in large quantities. These systems are regulated or controlled, and very different material flows flow through them under very different operating conditions, for example, from -273 degrees Celsius to +640 degrees Celsius and operating pressures from 0 bar to 800 bar. The material flows can range from viscous to vaporous and from strongly basic to strongly acidic. Very different materials must be used for these very different material flows.

[0004] A wide variety of pressure valves for material flows are known from the state of the art. As discussed above, these are made of a variety of materials, and the pressure valves must be extensively tested for material safety before use. Cracks, cavities, and foreign inclusions, in particular, can significantly impact the respective material quality. Such pressure valves are tested using ultrasound, magnetic flux measurements, X-rays, dye UV fluorescence measurements, and dye penetrant tests. However, these tests are complex and therefore costly due to the often complex geometry of the components of such pressure valves.

[0005] The object of the present invention is therefore to provide a pressure fitting which avoids the above-mentioned disadvantages at least to a large extent, so that the time-consuming and thus cost-intensive material tests can be considerably reduced.

[0006] This problem is solved according to the invention by a pressure fitting according to claim 1, a method according to claim 20 and a use according to claim 21.

[0007] The pressure fitting according to the invention for material flows (in the sense of the invention, the terms "material flow" and "material flow" are identical) has a base body with a pressure-reducing unit, characterized in that a.) a material interruption is realized between the base body, for example and in particular a pipeline, and the pressure-reducing unit, for example and in particular a type of sleeve, and / or b.) a material interruption is realized between a wall body, for example and in particular a pipeline, and the base body arranged in the interior of the wall body, for example and in particular a pipeline.

[0008] The term "material interruption" in the sense of the invention refers to an interruption of the material flow between the above-mentioned parts, i.e., the pressure-reducing unit, the base body, and the wall body. In other words: in the context of the invention, these parts do touch each other, either purely mechanically or, for example, and in particular, via welds, but they are always separate parts and not a single part to which the above parts can be assigned in their respective sections and areas.Thus, these parts do not merge seamlessly - as sections and areas of a single part - but are separated from one another in this sense in a material-technical sense, so that corresponding material interruptions are realized, which can appear, for example and in particular when the parts only touch one another, as if they were cracks or gaps. These are of course not real cracks, which would obviously have a negative impact on the material of the respective part, but rather these material interruptions that look like cracks or gaps between the individual parts (i.e. pressure-reducing units, base body and wall body).These material interruptions generally make it easier to carry out the necessary material tests, as the individual parts can be examined separately prior to later assembly into a pressure fitting, thus avoiding complex structures that are generally relatively difficult to examine / test.

[0009] It is advantageous if a.) the base body is a molded part and / or b.) the wall body is a molded part, since this allows costs to be saved when constructing a pressure fitting according to the invention.

[0010] Furthermore, it is advantageous if a.) the base body is designed without any castings and / or forgings, for example as a pressed part, and / or b.) the wall body is designed without any castings and / or forgings, for example and in particular as a pressed part, since such parts can generally be better examined for material defects, for example and in particular by means of ultrasonic measurements.

[0011] When the base body is designed as a molded part, many material tests are eliminated, as such molded parts are usually pre-tested for certain material qualities. While the design as a non-cast and / or non-forged part does not eliminate the necessary material tests per se, they are relatively easy to perform, as castings and / or forgings are often only inadequately tested; this particularly applies to ultrasonic testing. Nevertheless, in individual cases, it may be advisable for the base body to be cast, forged, pressed, or drawn.

[0012] In the context of the invention, the term "molded parts" refers to components that often correspond to simple geometric configurations, such as, and in particular, pipes, T-pieces, cross-pieces, bends, and Y-pieces, and are often also material-tested, although the latter criterion is not mandatory. Such molded parts are manufactured in very large quantities and are usually - but not necessarily - free of castings and / or forgings. Castings and forgings are generally very difficult to test, and this particularly applies to ultrasonic measurements.

[0013] In this context, it is advantageous and proven if the base body fitting and / or the wall body fitting are / is a pipe, T-piece, Y-piece, crosspiece, elbow, or spherical piece. These shapes represent the most common and usual shapes of the fittings.

[0014] In many cases, the pressure-reducing unit and / or the base body and / or the wall body advantageously consists, as proven, of one of the following materials: pipeline materials, C 22, St. 52, heat-resistant ferritic materials, 16Mo3, 13CrMo44, 10CrMo910, 14MoV63, P91, P92, C22.8, austenitic materials, in particular 1.4571, 1.4580, 1.4404, 1.4301, 1.4550, 1.4581, 1.4401, 1.4521, 1.4552, 1.4541, 1.4520, steel casing pipes, PE, PE-X, PP, PVC, copper materials, copper metal alloys, bronzes, aluminum multi-component bronze, AB45, ESM, molten steels, CW024A, CW509L, CW610N, CW613N, CW614N, CW617N, CW702R, CW706R, CW717R, CW715R, CW352H, CW354H, CW307G, CW353H, P195TR1, P195TR2, P235TR1, P235TR2, P195GH, P235GH, P265GH, 8MoB5-4, 16Mo3, XllCrMo9-l+l, 13CrMo4-5, X20CrMoVll-l, P355NH, P195GH, P285GH, 16Mo3, P355NH, materials of EN 12952 / 12953, P215NL, P265NL, P355N, P480NL1, P620Q, P890QH, 8460NH, L290NB, L450QB, L245NB, L555MB, L360MB, L280MB, materials of EN 10208-2, materials of AD2000 - HP110R, AD2000 - HP120R, AD2000 -W2, AD2000 - W / 6, AD2000 - W6 / 1, AD2000 - W6 / 2, glass, ceramics, plastics, polyethylene, polyamide, polyvinyl chloride, polytetrafluoroethylene, Polyoxymethylene.

[0015] In this context, it is advantageous, and proven, for the pressure-reducing unit to be designed without any castings and / or forgings, in order to avoid major difficulties during material testing, especially during ultrasonic testing. However, in individual cases, it may be advisable for the pressure-reducing unit to be cast, forged, pressed, or drawn.

[0016] It is particularly advantageous, as proven, if a.) the pressure-reducing unit is designed as a sleeve-like individual part that can be inserted into the base body, and / or b.) the base body is designed as an individual part that can be inserted into the wall body, in order to provide a flexible system for pressure fittings in order to meet the specific requirements for material, safety and pressure reduction.

[0017] In order to ensure particularly reliable operation, it is advantageous if a.) the pressure-reducing unit is mechanically fixed in the base body, for example and in particular if the pressure-reducing unit is mechanically fixed by means of pin-shaped elements, spot welding, welding, gluing or by means of a thread, and / or b.) the base body is mechanically fixed in the wall body, for example and in particular by means of pin-shaped elements, spot welding, welding or gluing.

[0018] Furthermore, it is advantageous and proven if the pressure-reducing unit has at least one pressure-reducing material flow opening in order to create a pressure reduction appropriate to the respective application through dimensioning.

[0019] The pressure-reducing unit can advantageously be made of a tough material, such as Cr-Ni steel or martensitic chromium steel, which is more resistant to cavitation. If the pressure-reducing unit is welded to the base body, attention must be paid to weldability by selecting a suitable material. The pressure-reducing unit may need to be buffered with a material compatible with the weld seam and the base body.

[0020] A.) For secure sealing of the pressure-reducing unit in the base body, this is advantageously designed in the form of a sleeve, which in the assembled state is introduced into the interior of the base body and interacts in a force-locking and / or form-locking manner with an inner contact surface of the base body, and / or b.) For secure sealing of the base body in the wall body, the base body in the assembled state is introduced into the interior of the wall body and interacts in a force-locking and / or form-locking manner with the wall body.

[0021] In this context, it is advantageous and proven effective if a pre-compressed sealing element, for example and in particular made of graphite, PTFE, or a rubber-like material, is arranged inside the base body between the pressure-reducing unit and another sealing part following the pressure-reducing unit. The pre-compressed sealing element exerts additional sealing pressure on the inner contact surface of the base body, or on the pressure-reducing unit and the sealing part.

[0022] In this context, it is advantageous and proven if the wall body fitting is a pipe, T-piece, Y-piece, cross piece, bend piece or a spherical piece.

[0023] As an alternative to the sealing part and sealing element in the pressure fitting according to the invention, it is provided and also advantageous, due to a high degree of tightness between the pressure-reducing unit and the base body, that the pressure-reducing unit is held in the base body by means of a press fit, in particular, as proven when the pressure-reducing unit and / or the base body are designed as conical or cylindrical surfaces with regard to their interacting surfaces.

[0024] In this context, it is advantageous that the conical and / or cylindrical surfaces have circumferential grooves and / or annular comb profiles when viewed in radial cross-section, as particularly reliable seals between the base body and the pressure-reducing unit are achieved.

[0025] Furthermore, it is advantageous, as proven, if the press fit is realized by joining the pressure reducing unit, which has been cooled with respect to the assembly temperature range, which is generally + 10 °C to + 40 °C, of ​​the pressure fitting, with the base body, which has advantageously been heated with respect to the assembly temperature range, for example and in particular, as proven, if the pressure reducing unit is cooled by means of liquid nitrogen and / or the base body is heated to a temperature in the temperature range of + 200 °C to + 400 °C, in order to then be joined together and thus realize a particularly strong joining of the base body and the pressure reducing unit.

[0026] Furthermore, the following are claimed:

[0027] A method for operating pressure fittings, in which a pressure fitting according to the invention is used.

[0028] A use of pressure-reducing units, base bodies and wall bodies, shown in one of the claims 1 to 19, in a pressure fitting according to one of the claims 1 to 19. The invention is explained in more detail in the following embodiments merely by way of example and not by way of limitation, wherein:

[0029] Figure 1 is a sketchy cross-sectional view of various molded parts; Figure 2 is a sketchy cross-sectional view of an embodiment of a pressure-reducing unit including a sealing part and a pre-compressed sealing element;

[0030] Figure 3 is a sketchy cross-sectional view of an embodiment of a base body;

[0031] Figure 4 is a sketchy cross-sectional view of the parts shown in Figures 2 and 3 in the assembled state;

[0032] Figure 5 is a cross-sectional diagram of the parts shown in Figure 4 in the assembled state, arranged in a wall body; Figure 6 is a cross-sectional diagram of a further embodiment for cryogenics (double-walled) compared to the one shown in Figure 5;

[0033] Figure 7 - a sketchy cross-sectional view of a seal-free press fit of the base body and pressure-reducing unit;

[0034] Figure 8 - a sketchy cross-sectional view of the interference fit shown in Figure 7 and its interacting surfaces.

[0035] Figure 1 shows various molded parts 3 which can function both as base body 1 and as wall body 8 in multi-walled pressure fittings.

[0036] The pressure valve for material flows has a base body 1 with a pressure-reducing unit 2, wherein the base body 1 a.) is a molded part 3 and b.) is designed to be free of castings and forgings.

[0037] The base body fitting is a T-piece.

[0038] The base body 1 consists of one of the following materials: pipeline materials, C 22, St. 52, heat-resistant ferritic materials, 16Mo3, 13CrMo44, 10CrMo910, 14MoV63, P91, P92, C22.8, austenitic materials, in particular 1.4571, 1.4580, 1.4404, 1.4301, 1.4550, 1.4581, 1.4401, 1.4521, 1.4552, 1.4541, 1.4520, steel casing pipes, PE, PE-X, PP, PVC, copper materials, copper metal alloys, bronzes, aluminum multi-component bronze, AB45, ESM, molten steels, CW024A, CW509L, CW610N, CW613N, CW614N, CW617N, CW702R, CW706R, CW717R, CW715R, CW352H, CW354H, CW307G, CW353H, P195TR1, P195TR2, P235TR1, P235TR2, P195GH, P235GH, P265GH, 8MoB5-4, 16Mo3, XllCrMo9-l+l, 13CrMo4-5, X20CrMoVll-l, P355NH, P195GH, P285GH, 16Mo3, P355NH, materials of EN 12952 / 12953, P215NL, P265NL, P355N, P480NL1, P620Q, P890QH, 8460NH, L290NB, L450QB, L245NB, L555MB, L360MB, L280MB, materials of EN 10208-2, materials of AD2000 - HP110R, AD2000 - HP120R, AD2000 -W2, AD2000 - W / 6, AD2000 - W6 / 1, AD2000 - W6 / 2. In this case, the pressure-reducing unit 2 is a cast part, but can also be designed without a cast part.

[0039] The pressure-reducing unit 2 is sleeve-like and designed as a single part that can be inserted into the base body.

[0040] The pressure-reducing unit 2 is mechanically fixed in the base body 1, namely by means of pin-shaped elements 9.

[0041] The pressure-reducing unit 2 consists of one of the following materials: piping materials, C 22, St. 52, heat-resistant ferritic materials, 16Mo3, 13CrMo44, 10CrMo910, 14MoV63, P91, P92, C22.8, austenitic materials, in particular 1.4571, 1.4580, 1.4404, 1.4301, 1.4550, 1.4581, 1.4401, 1.4521, 1.4552, 1.4541, 1.4520, steel casing pipes, PE, PE-X, PP, PVC, copper materials, copper metal alloys, bronzes, aluminum multi-component bronze, AB45, ESM, molten steels, CW024A, CW509L, CW610N, CW613N, CW614N, CW617N, CW702R, CW706R, CW717R, CW715R, CW352H, CW354H, CW307G, CW353H, P195TR1, P195TR2, P235TR1, P235TR2, P195GH, P235GH, P265GH, 8MoB5-4, 16Mo3, XllCrMo9-l+l, 13CrMo4-5, X20CrMoVll-l, P355NH, P195GH, P285GH, 16Mo3, P355NH, materials of EN 12952 / 12953, P215NL, P265NL, P355N, P480NL1, P620Q, P890QH, 8460NH, L290NB, L450QB, L245NB, L555MB, L360MB, L280MB, materials of EN 10208-2, materials of AD2000 - HP110R, AD2000 - HP120R, AD2000 -W2, AD2000 - W / 6, AD2000 - W6 / 1, AD2000 - W6 / 2.

[0042] The pressure-reducing unit 2 has at least one pressure-reducing material flow opening 4.

[0043] The pressure-reducing unit 2 is designed in the form of a sleeve which, when inserted into the interior of the base body 1 in the assembled state, interacts in a force-locking and / or form-locking manner with an inner contact surface 5 of the base body 1.

[0044] Inside the base body 1, a pre-compressed sealing element 7 made of graphite is arranged between the pressure-reducing unit 2 and a further sealing part 6 following the pressure-reducing unit 2.

[0045] In a multi-walled pressure fitting, the base body 1 is surrounded by at least one wall body 8, which is a.) a shaped body 3 and b.) is designed to be free of castings and forgings.

[0046] The wall body fitting is a T-piece.

[0047] The shape of the wall body 8 corresponds to the shape of the base body 1.

[0048] The wall body 8 consists of one of the following materials: pipeline materials, C 22, St. 52, heat-resistant ferritic materials, 16Mo3, 13CrMo44, 10CrMo910, 14MoV63, P91, P92, C22.8, austenitic materials, in particular 1.4571, 1.4580, 1.4404, 1.4301, 1.4550, 1.4581, 1.4401, 1.4521, 1.4552, 1.4541, 1.4520, steel casing pipes, PE, PE-X, PP, PVC, copper materials, copper metal alloys, bronzes, aluminum multi-component bronze, AB45, ESM, molten steels, CW024A, CW509L, CW610N, CW613N, CW614N, CW617N, CW702R, CW706R, CW717R, CW715R, CW352H, CW354H, CW307G, CW353H, P195TR1, P195TR2, P235TR1, P235TR2, P195GH, P235GH, P265GH, 8MoB5-4, 16Mo3, XllCrMo9-l+l, 13CrMo4-5, X20CrMoVll-l, P355NH, P195GH, P285GH, 16Mo3, P355NH, materials of EN 12952 / 12953, P215NL, P265NL, P355N, P480NL1, P620Q, P890QH, 8460NH, L290NB, L450QB, L245NB, L555MB, L360MB, L280MB, materials of EN 10208-2, materials of AD2000 - HP110R, AD2000 - HP120R, AD2000 -W2, AD2000 - W / 6, AD2000 - W6 / 1, AD2000 - W6 / 2, glass, ceramics, plastics, polyethylene, polyamide, polyvinyl chloride, polytetrafluoroethylene, Polyoxymethylene.

[0049] The arrows shown in the figures indicate the flow direction of the respective medium, in this case, water. It can be seen how the water flows into the base body 1 and the pressure-reducing unit 2, and then redirects and leaves the latter again with reduced pressure, before exiting the base body 1.

[0050] In a multi-walled design, the intermediate space 14 can, for example, and in particular, be designed either as a vacuum, a low-pressure space, a high-pressure space, or flooded with a medium; the medium in the intermediate space 14 can be the same medium that originates from the interior of the base body 1 or is supplied to it. Figure 5:

[0051] The T-piece has recesses A for areas 11, 5, and 7. The pressure-reducing part 2 with opening 4 is inserted into the recess A in the base body 1; then the seal 7 is inserted. The ring 4 / 6 is then inserted. There is a small gap between 4 and 2. Parts 4 / 6 are pressed against 2 by a lifting movement until the gap pre-compresses the seal 7. The seal 7, made of graphite, for example, is pre-tensioned to such an extent that 7 seals off the pressure to be sealed. In the tensioned state (gap approximately zero), 6 / 4 is fixed, for example, using pins or welding / tack welding. The seal 7 is pre-compressed to a density of approximately 1.2 g / cm3 in the non-installed state. During installation, the ring 7 is further compressed to a density of approximately 1.3 to 1.9 g / cm3, depending on the operating pressure. The hole SB should be central / centric.Part 2, for example, can be fixed centrally at three points around the circumference. The installed parts 2, 5, 7, and 4 are tested for leaks. The outer T-piece 8 is split lengthwise (two half-shells). Part 1 is inserted into the half-shell; spacers are previously fixed by welding; the second half-shell is placed on the first shell and welded all around. Part 1 is fitted with a connecting sleeve RE before assembly.

[0052] Figure 6 shows an example of a special double-walled embodiment for cryogenics or toxic material flows. A material flow (arrow) flows in the base body 1. This base body 1 is a pipe RL, connected (e.g. by welding) on ​​both sides. The material flow flows through a throttle body. The stroke of one of the throttle bodies changes an annular gap and thus changes the flow. The three-dimensional unit forms a wall which forces the flow to flow through the throttle body (seat S / cone K). The flow rate is regulated according to the stroke position. The wall body 8 encloses the base body 1. The wall body 8 is generally connected to an external line. There is a hollow space between the base body 1 and the wall body 8, for example the inner pipe RLi and the outer pipe RLä.This cavity can fulfill several functions: Insulation - vacuum, for example cryogenic liquids, toxic substances - warning system. The material flow must be prevented from escaping. Therefore, the tried and tested use of metallic bellows that follow the stroke movement, for example 13.1 Separation between material flow and vacuum space and 13.2 Separation between vacuum space and atmosphere. Figure 6 shows a double-walled valve installed in a double-wall system. Firstly, the double line must be routed over the valve and must also encompass (insulate or monitor) the valve space. Figure 6 shows the outer pipe RLä and the inner pipe RLi. In a valve, the throttling point is changed from the outside using the seat S / plug K and stroke (by positioning the plug K in the seat S; the so-called throttling). The main position is achieved by moving the valve position.In a double-wall system, a valve must seal the stroke adjustment (spindle movement) very well (e.g., tested using a helium leak test). Such high tightness values ​​can only be achieved with Meta II bellows, such as 13.1 and 15.1. For example, 15.1 seals the atmosphere against vacuum, and 13.1 seals the material flow against vacuum. The T-steels used (e.g., parts 8 and 1) are preferably compression-molded materials—for example, the austenitic CrNi material 1.4580 can be used. This achieves high temperature, pressure, and chemical resistance to hydrogen embrittlement. Figures 7 and 8:

[0053] As an alternative to the sealing part and sealing element in the pressure fitting according to the invention, it is provided and also advantageous, due to a high level of tightness between the pressure-reducing unit 2 and the base body 1, that the pressure-reducing unit 2 is held in the base body 1 by means of a press fit, in particular, as proven when the pressure-reducing unit 2 and / or the base body 1 are designed as conical or cylindrical surfaces with regard to their interacting surfaces FW1 and FW2. In this context, it is advantageous, since particularly reliable tightness is achieved between the base body 1 and the pressure-reducing unit 2, that the conical and / or cylindrical surfaces have circumferential grooves (thus annular material recesses) FWR and / or annular comb profiles (thus annular material elevations) when viewed in radial cross-section.

[0054] Furthermore, it is advantageous, as proven, if the press fit is realized by joining the pressure-reducing unit 2 cooled with respect to the working temperature range of the pressure fitting with the base body 1 heated with respect to the assembly temperature range, for example and in particular, as proven, if the pressure-reducing unit 2 is cooled by means of liquid nitrogen and / or the base body 1 is heated to a temperature in the temperature range from + 200 ° C to + 400 ° C in order to then be joined together and thus to realize a particularly strong joining of the base body 1 and the pressure-reducing unit 2.

[0055] With regard to all figures, it can be seen that, according to the invention, corresponding material interruptions in the sense described above are realized between the base body 1 and the pressure-reducing unit 2 as well as between the wall body 8 and the base body 1.

Claims

Patent claims Pressure fitting for material flows, comprising a base body (1) with a pressure-reducing unit (2) arranged inside the base body (1), characterized in that a.) a material interruption is realized between the base body (1) and the pressure-reducing unit (2), and / or b.) a material interruption is realized between a wall body (8) and the base body (1) arranged inside the wall body (8). Pressure fitting according to claim 1, characterized in that a.) the base body (1) is a shaped part (3), and / or b.) the wall body (8) is a shaped part (3). Pressure fitting according to one of claims 1 to 2, characterized in that a.) the base body (1) is designed to be free of castings and / or forgings, and / or b.) the wall body (8) is designed to be free of castings and / or forgings.Pressure fitting according to one of claims 1 to 3, characterized in that the base body shaped part and / or the wall body shaped part is / is a pipe, T-piece, Y-piece, cross piece, bend piece or a spherical piece. Pressure fitting according to one of claims 1 to 4, characterized in that the pressure-reducing unit (2) and / or the base body (1) and / or the wall body (8) consist / consists of one of the following materials: pipeline materials, C 22, St. 52, heat-resistant ferritic materials, 16Mo3, 13CrMo44, 10CrMo910, 14MoV63, P91, P92, C22.8, austenitic materials, in particular 1.4571, 1.4580, 1.4404, 1.4301, 1.4550, 1.4581, 1.4401, 1.4521, 1.4552, 1.4541, 1.4520, steel casing pipes, PE, PE-X, PP, PVC, copper materials, copper metal alloys, bronzes, aluminum multi-component bronze, AB45, ESM, molten steels, CW024A, CW509L, CW610N, CW613N, CW614N, CW617N, CW702R, CW706R, CW717R, CW715R, CW352H, CW354H, CW307G, CW353H, P195TR1, P195TR2, P235TR1, P235TR2, P195GH, P235GH, P265GH, 8MoB5-4, 16Mo3, XllCrMo9-l+l, 13CrMo4-5, X20CrMoVll-l, P355NH, P195GH, P285GH, 16Mo3, P355NH, materials of EN 12952 / 12953, P215NL, P265NL, P355N, P480NL1, P620Q, P890QH, 8460NH, L290NB, L450QB, L245NB, L555MB, L360MB, L280MB, materials of EN 10208-2, materials of AD2000 - HP110R, AD2000 - HP120R, AD2000 -W2, AD2000 - W / 6, AD2000 - W6 / 1, AD2000 - W6 / 2, glass, ceramics, plastics, polyethylene, polyamide, polyvinyl chloride, polytetrafluoroethylene, Polyoxymethylene. Pressure fitting according to one of claims 1 to 5, characterized in that the pressure-reducing unit (2) is designed without any castings and / or forgings. Pressure fitting according to one of claims 1 to 6, characterized in that a.) the pressure-reducing unit (2) is sleeve-like and designed as an individual part that can be inserted into the base body, and / or b.) the base body (1) is designed as an individual part that can be inserted into the wall body (8). Pressure fitting according to one of claims 1 to 7, characterized in that a.) the pressure-reducing unit (2) is mechanically fixed in the base body (1), and / or b.) the base body (1) is mechanically fixed in the wall body (8). Pressure fitting according to one of claims 1 to 8, characterized in that the pressure-reducing unit (2) and / or the base body (1) are / is mechanically fixed by means of pin-shaped elements (9), spot welding, welding, or by means of a thread.Pressure fitting according to one of claims 1 to 9, characterized in that the pressure-reducing unit (2) has at least one pressure-reducing material flow opening (4). Pressure fitting according to one of claims 1 to 10, characterized in that a.) the pressure-reducing unit (2) is designed like a sleeve, which, in the assembled state, is introduced into the interior of the base body (1) and interacts in a force-fitting and / or form-fitting manner with an inner run-on surface (5) of the base body (1), and / or b.) the base body (1), in the assembled state, is introduced into the interior of the wall body (8) and interacts in a force-fitting and / or form-fitting manner with the wall body (8). Pressure fitting according to claim 11, characterized in that a pre-compressed sealing element (7) is arranged in the interior of the base body (1) between the pressure-reducing unit (2) and a further sealing part (6) following the pressure-reducing unit (2).Or pressure fitting according to claim 12, characterized in that the pre-compressed sealing element (7) consists of graphite, PTFE, or a rubber-like material. Pressure fitting according to claim 11, characterized in that the pressure-reducing unit (2) is held in the base body (1) by means of a press fit. Pressure fitting according to claim 14, characterized in that the pressure-reducing unit (2) and / or the base body (1) are designed as conical or cylindrical surfaces with respect to their interacting surfaces. Pressure fitting according to claim 15, characterized in that the. conical and / or cylindrical surfaces have circumferential grooves and / or annular comb profiles when viewed in radial cross-section. Pressure fitting according to one of claims 14 to 16, characterized in that the press fit is realized by joining the pressure-reducing unit (2) cooled with respect to the assembly temperature range of the pressure fitting to the base body (1). Pressure fitting according to claim 17, characterized in that the base body is heated with respect to the assembly temperature range before joining. Pressure fitting according to one of claims 17 to 18, characterized in that the pressure-reducing unit (2) is cooled by means of liquid nitrogen and / or the base body (1) is heated to a temperature in the temperature range from +200°C to +400°C in order to be subsequently joined together. Method for operating pressure fittings, characterized in that a pressure fitting according to one of claims 1 to 19 is used.Use of pressure-reducing units (2), base bodies (1) and wall bodies (8) as shown in one of claims 1 to 19 in a pressure fitting according to one of claims 1 to 19.

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