Accumulator preferably for a motor vehicle

Abstract

An accumulator (A) for separating gaseous and liquid components of a refrigerant from one another and / or for collecting and storing the refrigerant, preferably for a motor vehicle, comprising: a tube (RZ) and at least one cap (D). According to the invention, the tube (RZ) has at least one reducer (R), wherein the tube (RZ) has at least one section (AB), the cap (D) having a cylindrical shape and being inserted into the at least one section (AB), the at least one reducer (R) and the cap (D) at least partially contacting each other, and the cap (D) and the tube (RZ) being metallurgically bonded. According to the invention, the accumulator (A) can be used in a refrigerant circuit of a motor vehicle. A method for manufacturing the accumulator is described.

Description

[0001] The invention relates to an accumulator and an assembly, preferably for a motor vehicle, for collecting and storing refrigerant and separating liquid and gaseous components of the refrigerant, as well as the use in a refrigerant circuit and a method for producing the accumulator.

[0002] The document EP 2 102 566 B1 discloses an accumulator for a refrigerant circuit for a motor vehicle (automotive cooling system), comprising a tube (tubular housing element) designed to receive a suction pipe (pipe arrangement) in which refrigerant (coolant) then flows, wherein a base is provided which is designed to close a first end of the tube, and wherein a pair of connections for refrigerant inlet pipes and outlet pipes are provided, and wherein it is provided that it can be sealed by a cover at an end of the tube opposite the first end, wherein said cover is a substantially cylindrically shaped accumulator equipped with the tube and said cover, which are made of aluminum, as well as said suction pipe made of plastic, wherein the suction pipe is made of two plastic half-shells welded together,wherein the cover is dome-shaped and is intended to be inserted at least partially into the tube by means of an insert portion having a smaller diameter than the inner diameter of the tube, and terminates with a circumferential stop on which an end portion of the tube is deformed and shaped by magnetic pulse welding (magnetic pulse explosion welding) until the crystalline planes of the surfaces in contact with each other penetrate,whereby essentially a single body is formed, thereby creating the seal. During operation, for example, in a motor vehicle, the refrigerant in the refrigerant circuit has varying pressures. The accumulator is subjected to these pressure changes and must have sufficient strength. Strength is understood to be the ability of the accumulator to withstand mechanical stress (in this case, alternating pressure stress) until failure occurs. Failure can be a fracture or an unacceptable deformation. The dome-shaped cover creates a disadvantageous cut in the tube. This cut is a notch. This notch adversely reduces the strength of the accumulator under pressure. It is under discussion,to replace the currently used refrigerants, such as R123a, with a refrigerant such as R744. R744 can result in three to four times higher pressure in the refrigerant circuit than R123a, and thus the requirements for the strength of the accumulator can increase.

[0003] The device according to the invention with the features of the independent patent claim has the advantage that the accumulator has a sufficiently high strength when the accumulator is flowed through by a coolant which has a significantly higher pressure than the coolants currently used in series.

[0004] The starting point for the invention is an accumulator. The accumulator according to the invention for separating gaseous and liquid components of a refrigerant from one another and / or for collecting and storing the refrigerant can preferably be used for a motor vehicle. The accumulator according to the invention has a tube and at least one cover. According to the invention, the tube has at least one reducer. Wherein the tube has at least one section. Wherein the at least one cover has a cylindrical shape and is inserted into the at least one section. Wherein the at least one reducer and the at least one cover at least partially touch one another, wherein the at least one cover and the tube are integrally connected. The tube can be an elongated hollow body; the length can be significantly greater than the diameter of the tube (hollow body).The tube can have an axial axis and an axial length that runs along the length of the tube (the hollow body). It is possible for the tube and the at least one cover to comprise a metallic material, such as an aluminum alloy. It is conceivable for the tube to be extruded or drawn seamlessly. The at least one cover can be produced by an impact molding process. According to a European directive, the use of refrigerants with a high global warming potential, such as R123a, in a motor vehicle refrigerant circuit should be avoided. There is discussion about using carbon dioxide (R744) instead in a motor vehicle refrigerant circuit. The currently used R123a, for example, has a global warming potential that is approximately 1300 times greater than carbon dioxide (R744).The use of carbon dioxide advantageously enables greater efficiency of the refrigerant circuit in motor vehicles, as less fuel was required as an energy source to operate the refrigerant circuit in comparative measurements by the Federal Motor Transport Authority. Carbon dioxide (R744) can have three to four times the pressure of current series-produced refrigerants such as R123a. For this reason, the pressure change load on the accumulator in the refrigerant circuit can increase significantly. The at least one cover and the tube are each bonded to one another in the area of ​​the at least one section. This connection, which is long in the axial direction, can advantageously increase the strength of the bonded connection and thus of the accumulator.The integral connection ensures that the accumulator according to the invention is sealed fluid-tight and dust-tight by the at least one cover. A fluid-tight connection is understood to mean that no or only negligible amounts of fluid can pass through the connection. And a dust-tight connection is understood to mean that no or only negligible amounts of dirt particles can pass through the connection. The at least one cover can no longer shift in the axial direction due to the integral connection between the cover and the tube. An accumulator according to the invention can be tested before use at a significantly higher pressure than the pressure that occurs during operation.When testing an accumulator according to the invention, it may be possible that the at least one cover only moves in the axial direction at a significantly greater pressure and that the accumulator according to the invention is no longer fluid-tight and dust-tight at a greater pressure than an accumulator described in the prior art. The at least one reduction can advantageously prevent the at least one cover from slipping into the tube before the material connection between the two components is created. In addition, the at least one reduction increases the strength of the accumulator under compressive load and bending load of the tube. In a first embodiment according to the invention, the accumulator can have two covers and thus two reducers and two sections. With the two covers, the tube can be closed fluid-tight and dust-tight at the top and bottom.In a second embodiment of the invention, the accumulator can have a lid. The tube can be sealed at the top with a lid in a fluid-tight and dust-tight manner and at the bottom end, for example, with a fold. In a further embodiment, the accumulator can have a lid. The tube can be sealed at the top with a lid in a fluid-tight and dust-tight manner and at the bottom end, for example, with a base. The tube and the base can be formed as a single piece. This is possible, for example, using the primary forming process or reverse extrusion manufacturing methods.

[0005] According to the invention, the at least one cover and the tube are connected in the region of the at least one section by means of magnetic pulse welding. Magnetic pulse welding, also known as welding using electromagnetic pulse technology, is a pressure welding process. Magnetic pulse welding uses electromagnetic forces to weld two workpieces together. With magnetic pulse welding, high-quality welds can be produced between workpieces made of similar or dissimilar metals in microseconds. The use of shielding gases or welding consumables is not necessary. Magnetic pulse welding is based on a very short electromagnetic pulse. This pulse can be generated, for example, by quickly discharging capacitors into a coil via switches with low inductance. The pulsed current has a very high amplitude and frequency.In this way, a high-density magnetic field can be generated that creates an eddy current in one of the workpieces. This creates repulsive Lorentz forces and a high magnetic pressure. This pressure is much greater than the yield strength of the material of each of the two workpieces and causes one of the two workpieces to accelerate, causing it to collide with the other at an impact speed of up to 500 meters per second. Magnetic pulse welding results in high plastic deformation with high shear stress, a large impact, high temperatures, and oxide breakup in the contact zone. This results in solid-state welding without large-volume melting of the workpieces. At least one section is produced before the material-to-metal bond is created.The following conditions must be met in order to achieve a strong, material-tight connection between the pipe and the at least one cover: the impact of the pipe must be below the speed of sound of the local material, high pressure must occur, and no fusion must occur during the impact (pressure must therefore not be too high). It is possible for the at least one section to be represented by an expansion of the pipe, for example by inserting a mandrel into the pipe. The pipe has tolerances on the inside diameter that are determined by the manufacturing process of the pipe, for example by drawing the pipe. The at least one cover has tolerances on the outside diameter that are determined by the manufacturing process of the cover, for example by extrusion of the cover.As a rule, the tolerances that occur on the tube are larger than those that occur on the cover. These tolerances determine the initial distance between the tube (flyer) and at least one cover (target) before magnetic pulse welding. Experimental observations and numerical studies have shown that the initial distance between the tube (flyer) and at least one cover (target) plays a crucial role in the quality of the resulting weld. The initial distance has a significant influence on the progressive impact of the tube (flyer) on the cover (target), the collision behavior, the resulting pressure, and thus on the development of the weld.Since at least one section can be manufactured with more precise (smaller) tolerances on the inner diameter by means of the expansion process, it is possible to specify the initial distance more precisely and thus it is advantageously possible to better adjust the process parameters of the magnetic pulse welding, since the progressive impact of the tube (flyer) on the cover (target) as well as the occurring pressure can be more precisely predetermined or adjusted.

[0006] The tube may tend to plastically deform inward or outward due to the forces generated upon impact with at least one cover (bending along the axial axis). By reducing the at least one section, the stiffness of the tube can be advantageously increased, thus supporting the forces generated upon impact. Unintentional deformation of the tube can at least be reduced.

[0007] In a further embodiment of the accumulator according to the invention, the at least one section can each have a hollow cylindrical shape. The hollow cylindrical shape of the at least one section can be produced, for example, by widening the tube with a mandrel. In this way, it is possible to produce the at least one section with a small radial tolerance on the inner diameter. The at least one cover can have a cylindrical shape or a disc-like shape. The at least one cover can have a small radial tolerance on the outer diameter. The at least one section can have a hollow cylindrical shape and the at least one cover can have a cylindrical shape on the outside. In this way, the at least one cover and the at least one section, together with the small tolerances, form a matching pair.The initial distance between the at least one cover and the pipe can advantageously be adjusted even better to the welded joint before the material connection is created using magnetic pulse welding. This allows for an even higher-quality welded joint with sufficiently high strength at the high pressure that occurs in the refrigerant circuit when using carbon dioxide (R744).

[0008] In a further embodiment of the accumulator according to the invention, the tube can have an inner region. Wherein the at least one reducer can be arranged between the inner region and the at least one section. The at least one reducer can be arranged adjacent to the at least one section. The inner region can have a hollow cylindrical shape with a constant inner diameter. The at least one reducer can be arranged adjacent to the inner region. Through this arrangement of the at least one reducer, the forces occurring during magnetic pulse welding can be supported and unwanted deformation of the tube can at least be reduced or can be prevented. For example, a cylinder can be arranged in the inner region and a suction pipe can be arranged in the cylinder.

[0009] In a further embodiment of the accumulator according to the invention, the at least one reduction can be designed as an at least partially circumferential bead. The at least partially circumferential bead can be designed as a groove-shaped depression in the radial direction. It is possible for the at least one reduction to be produced in the form of a bead by means of a radial pressing process. Advantageously, the shape of the at least one reduction as a bead can provide even better support for the forces occurring during magnetic pulse welding, and any potentially occurring unwanted deformation of the tube is at least reduced or completely prevented. In a further embodiment of the invention, the at least one reduction can be designed as a circumferential bead.

[0010] In a further embodiment of the accumulator according to the invention, the tube can have a connection plate. In a further embodiment of the accumulator, the tube and the at least one cover can each have a connection plate and in a further embodiment of the accumulator, the at least one cover can have a connection plate. The accumulator according to the invention can, for example, be used in a refrigerant circuit together with other components. Using the connection plate, the accumulator according to the invention can advantageously be connected to other components of the refrigerant circuit. It is conceivable to connect the accumulator to one of the components using a force-fitting method such as clamping. Alternatively, it is possible for the accumulator to be connected to one of the components using a form-fitting method such as pressing or with a screw connection.It is conceivable that the connection plate has passages for a medium such as a refrigerant. The other components of the refrigerant circuit can be, for example, a condenser, an expansion valve, a compressor, and / or an evaporator. The components can be used in a refrigerant circuit, for example, in the following ways: a condenser for condensing a refrigerant, a collector according to the invention for collecting and storing the refrigerant, an expansion valve for expanding the refrigerant, an evaporator for evaporating the refrigerant, and a compressor for compressing the refrigerant.

[0011] In a further embodiment of the accumulator according to the invention, the at least one cover can have at least one passage opening for a medium. The at least one passage opening can be designed as a bore. In one exemplary embodiment, the at least one cover can have two passage openings for a medium, such as a refrigerant. In this way, the accumulator according to the invention can be connected to the high-pressure part and / or the low-pressure part of a refrigerant circuit.

[0012] In a further embodiment of the accumulator according to the invention, the tube can have at least one passage opening for a medium. The medium can be, for example, a refrigerant. The at least one passage opening can be designed as a bore. In this way, the accumulator according to the invention can be connected to the high-pressure part and / or the low-pressure part of a refrigerant circuit.

[0013] In a first use according to the invention, the accumulator according to the invention can be used in a refrigerant circuit for a motor vehicle. A refrigerant can flow through the refrigerant circuit. It is conceivable that carbon dioxide (R744), for example, flows through the refrigerant circuit. The refrigerant circuit for a motor vehicle can have the following components: a condenser for condensing a refrigerant, an accumulator according to the invention for separating gaseous and liquid portions of a refrigerant from one another and / or for collecting and storing the refrigerant, an expansion valve for expanding the refrigerant, an evaporator for evaporating the refrigerant, a compressor for compressing the refrigerant and the connecting lines. With the help of the evaporator, for example, heat can be extracted from the interior of a motor vehicle and this heat can be released to the environment via the condenser.The accumulator according to the invention can advantageously serve to increase the efficiency of the refrigerant circuit under different ambient conditions by storing refrigerant in the accumulator according to the invention and releasing it again when needed. The accumulator according to the invention can be designed in such a way that, among other things, a phase separation of a refrigerant having gaseous and liquid components can take place therein through gravity. The different ambient conditions can be understood, for example, to be the different seasons. Since the refrigeration circuit is closed and has only a maximum of one accumulator according to the invention, the refrigeration circuit can function in a self-regulating manner with the help of the accumulator according to the invention. Oil is required to lubricate the compressor of the refrigerant circuit. This oil can be mixed with the refrigerant.Due to gravity, liquid oil can collect at the bottom of the accumulator according to the invention, as the liquid oil can be heavier than the liquid refrigerant. This allows the oil to be separated from the refrigerant. The compressor can draw in the liquid oil, for example, via a suction pipe with an oil bore inside the accumulator according to the invention, and thus be lubricated.

[0014] In a first embodiment of the invention, the structural unit comprises a heat exchanger and an accumulator according to the invention. The accumulator can, for example, be illustrated in the first embodiment of the invention and comprise a cylinder. The heat exchanger winds around the cylinder at a constant pitch in the axial direction. The heat exchanger is an internal heat exchanger. The cold low-pressure part and the warm high-pressure part of a refrigerant circuit can advantageously exchange heat via the internal heat exchanger. In this way, the cold low-pressure part can be superheated. The structural unit can be arranged in a warm engine compartment of a motor vehicle. Advantageously, the introduction of heat into the accumulator can at least be reduced because the heat exchanger is arranged between the accumulator and the engine compartment. An undesired introduction of heat into the accumulator can reduce the performance of the accumulator.

[0015] The method according to the invention for producing an accumulator according to the invention comprises at least the following method steps: The production of the tube. It is possible for the tube to consist of an aluminum alloy. The tube can be seamless and, for example, drawn from a block while hot. Subsequently, a reduction is produced at the upper end and a lower end of the tube. The two reductions can be represented as a circumferential bead and can be produced, for example, by means of a radial pressing process. Subsequently, a section is produced at the upper end and a lower end of the tube. The two sections can be produced simultaneously or one after the other. The two sections are designed as an expansion of the tube and can be produced, for example, by means of a cone that is axially inserted or pressed into the tube.This advantageously makes it possible to create two areas on the pipe with a significantly smaller radial tolerance than the radial tolerances that arise during pipe manufacture. A first cover is then inserted into the section at the lower end of the pipe so that the first cover and the lower reducer partially touch each other. This advantageously prevents the first cover from slipping into the pipe. Since both the lower section has a small radial tolerance on the inside and the first cover has a small radial tolerance on the outside, a very precisely defined initial distance can be created between the first cover and pipe. This initial distance between the pipe (flyer) and cover (traget) has a major influence on the collision behavior of the pipe and the cover and therefore on the quality of the welded joint.A material-to-material connection is then created between the tube and the first cover using magnetic pulse welding, so that the tube is sealed fluid-tight and dust-tight at the lower end by the first cover. At least one further component is then inserted into the tube. For example, a cylinder with a suction pipe and a tubular heat exchanger wound around the cylinder can be inserted into the tube. A second cover is then inserted into the section at the upper end of the tube so that the cover and the upper reducer partially touch each other. This advantageously prevents the second cover from slipping into the tube. Since both the upper section has a small radial tolerance on the inside and the second cover has a small radial tolerance on the outside, a very precisely defined initial distance can be created between the first cover and the tube.A material-tight connection is then created between the tube and the second cover by means of magnetic pulse welding, so that the tube is sealed fluid-tight and dust-tight at the upper end by the second cover. Fig. 1a Sectional view of the accumulator according to the invention without components inside Fig. 1b Sectional view of the accumulator according to the invention with components inside

[0016] In Fig. 1 shows a section through a first embodiment of the accumulator A according to the invention. The accumulator A has the tube RZ and is sealed at the top and bottom by a cover D in a fluid-tight and dust-tight manner. The two covers D are each connected to the tube RZ by a weld. The weld is produced by magnetic pulse welding. The tube RZ essentially has a hollow cylindrical shape. It is conceivable that the tube RZ and the two covers D each comprise an aluminum alloy. The tube RZ can be produced, for example, by extrusion or drawn as a seamless tube. The inner diameter ZDI is different at different points. The two covers D each have a cylindrical shape and can be produced, for example, by impact molding. One cover D has the outer diameter AD. The axial direction AR can run counter to the direction of gravity.Here, the axial direction AR runs along the vertical direction of the accumulator A. The accumulator A has a reduction R at the top and bottom of the tube RZ. At the very top and bottom ends, the accumulator A has two sections AB. A cover D is inserted into each section AB. The two sections AB are shown as an expansion of the tube RZ. The upper reduction R is arranged below the upper section AB, opposite to the axial direction AR. The lower reduction R is arranged above the lower section AB in the axial direction AR. Due to the great length of the two sections AB, in or opposite to the axial direction AR, a weld seam of an advantageous length can be produced. The two reductions R are designed as a circumferential bead and can be produced, for example, by a radial pressing process. The outside of a cover D partially touches the inside of the reduction R.Since the reducer R has a smaller inner diameter ZDI than the outer diameter DA of the cover D, slipping of the cover D into the pipe RZ is advantageously prevented before the material connection between the cover D and the pipe RZ is established. In addition, the two reducers R increase the rigidity of the pipe RZ against undesired deformation when a force in or against the axial direction AR acts on the accumulator A. A force in the axial direction AR can occur, for example, when producing the welded connection between the pipe RZ and a cover D using magnetic pulse welding.

[0017] In Fig. Figure 1a shows a cross-sectional view of the accumulator A without any additional internal components in the first embodiment of the invention. The accumulator A has the interior region IB. Components not shown, such as an intake manifold or a swirl disk, can be arranged in the interior region IB. The two reducers R are each arranged between the interior region IB and the upper and lower sections Ab, respectively.

[0018] Shown in Fig.1b shows a cross-sectional view of the assembly 100 with the accumulator A and the heat exchanger WH in the first embodiment according to the invention. The accumulator A has the cylinder Z. The upper cover D has the high-pressure inlet HDZ and the low-pressure inlet NDZ. The lower cover D has the high-pressure outlet HDA and the low-pressure outlet NDA. The high-pressure outlet HDA and the low-pressure outlet NDA in the cover D are each represented by a bore. A refrigerant such as carbon dioxide (R744), for example, can flow through the bore. The accumulator A is connected to the high-pressure part of a refrigerant circuit (not shown) via the high-pressure inlet HDZ and the high-pressure outlet HDA. The accumulator or assembly 100 is connected to the low-pressure part of a refrigerant circuit (not shown) via the low-pressure inlet NDZ and the low-pressure outlet NDA. The cylinder Z is arranged in the accumulator A.A desiccant (not shown) and a suction pipe can be arranged inside the cylinder Z. Refrigerant with liquid and gaseous components can flow into the accumulator A. Carbon dioxide (R744), for example, could be used as the refrigerant. The accumulator A is designed in such a way that, among other things, phase separation of a refrigerant containing gaseous and liquid components takes place through gravity. The accumulator A has the swirl disk DS. With the help of the swirl disk DS, a flow of refrigerant can be deflected so that the flow has a component along the inner surface of the cylinder Z. In this way, the phase separation of the liquid and gaseous components of the refrigerant can be improved. The refrigerant can be mixed with an oil. The oil can be used to lubricate the moving parts of the refrigerant circuit (not shown).The heavier liquid portion of the refrigerant sinks together with the oil, while the lighter gaseous portion of the refrigerant can be sucked in by a compressor (not shown) via the suction pipe SG. The liquid oil separated from the refrigerant collects in the lower area of ​​the cylinder Z, also called the oil sump. Since the liquid oil is heavier than the liquid refrigerant, the compressor (not shown), for example, can suck in the oil through an oil bore (not shown). The assembly 100 has the accumulator A and the heat exchanger WH. The heat exchanger WT is an internal heat exchanger. The heat exchanger WT consists of a tube that winds around the cylinder Z with a constant pitch in the axial direction AR. The heat exchanger WH can be connected to the cylinder Z, for example, by means of a force-fitting connection.The cold low-pressure part and the warm high-pressure part of a refrigerant circuit (not shown) can exchange heat via the heat exchanger WH. List of reference symbols A rechargeable battery according to the invention 100 inventive assembly with heat exchanger and accumulator D Cover of the accumulator according to the invention RZ tube of the accumulator according to the invention R Reduction of the pipe AB section of the pipe AR axial direction IB Inside the pipe DA outer diameter of the lid RZDI inner diameter of the pipe WH Internal heat exchanger of the unit according to the invention SG intake manifold DA swirl disc Z cylinder NDZ low-pressure supply line NDA low-pressure drain line HDZ high-pressure supply line HDA high-pressure drain line QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2 102 566 B1

[0002]

Claims

[1] Accumulator (A) for separating gaseous and liquid components of a refrigerant from each other and / or for collecting and storing the refrigerant, preferably for a motor vehicle, comprising: - one pipe (RZ) - at least one lid (D) characterized by in that the pipe (RZ) has at least one reduction (R), wherein the pipe (RZ) has at least one section (AB), wherein the at least one cover (D) has a cylindrical shape and is inserted into the at least one section (AB), wherein the at least one reduction (R) and the at least one cover (D) at least partially touch each other, wherein the at least one cover (D) and the pipe (RZ) are connected by a material fit. [2] Accumulator (A) according to claim 1, characterized by that the at least one cover (D) and the pipe (RZ) are connected in the region of the at least one section (AB) by means of magnetic pulse welding. [3] Accumulator (A) according to claim 1 or 2, characterized by that the at least one section (AB) has a hollow cylindrical shape. [4] Accumulator (A) according to one of the preceding claims, characterized by that the pipe (RZ) has an inner region (IB), wherein the at least one reduction (R) is arranged between the inner region (IB) and the at least one section (AB). [5] Accumulator (A) according to one of the preceding claims, characterized by that the at least one reduction (R) is designed as an at least partially circumferential bead. [6] Accumulator (A) according to one of the preceding claims, characterized by that the tube (RZ) and / or the at least one cover (D) has a connecting plate (P). [7] Accumulator (A) according to one of the preceding claims, characterized by that the at least one cover (D) has at least one passage opening for a medium. [8] Accumulator (A) according to one of the preceding claims, characterized by that the pipe (RZ) has at least one passage opening for a medium. [9] Refrigerant circuit for a motor vehicle comprising an accumulator (A) according to at least one of claims 1 to 8. [10] Structural unit (100), preferably for a motor vehicle, comprising a heat exchanger (WH) and an accumulator (A) according to at least one of claims 1-8. [11] Method for producing an accumulator (A) according to claims 1 to 8, comprising the following method steps: - Manufacturing the pipe (RZ). - Create one reducer (R) at the top and one at the bottom of the pipe (RZ) - Manufacture one section (AB) at the top and one at the bottom of the pipe (RZ) - Insert a first cover (D) into the section (AB) at the lower end of the pipe (RZ) so that the first cover (D) and the lower reduction (R) partially touch each other - Creating a material-tight connection between the pipe (RZ) and the first cover (D) by means of magnetic pulse welding, so that the pipe (RZ) is sealed fluid-tight and dust-tight at the lower end by the first cover (D). - Insertion of at least one additional component into the pipe (RZ) - Insert a second cover (D) into the section (AB) at the upper end of the pipe (RZ) so that the second cover (D) and the upper reduction (R) partially touch each other - Creating a material-tight connection between the pipe (RZ) and the second cover (D) by means of magnetic pulse welding, so that the pipe (RZ) is sealed fluid-tight and dust-tight at the upper end by the second cover (D).

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