CZ20001784A3 - A method for producing a ceramic chimney inner tubular member and a ceramic member with molded shoulder at the tubular ends - Google Patents

Abstract

The method of manufacturing a ceramic chimney inner tube element with facing shoulders on the tube ends for connection with another chimney inner tube element consists in that the chimney inner tube element is always pressed at one end (11) from the inside outwards and at the other end (10) from the outside inwards, along the circumference by half the wall thickness into the shape of a formed shoulder. The chimney inner tube element consists of a material which is 50 percent of its volume formed by cavities (2) forming channels running in the longitudinal direction of the tube element

Description

Method of manufacturing a ceramic chimney inner tube element (with formed shoulders on the tube ends)

Technical field

The invention relates to a method of manufacturing a ceramic chimney inner tube element with formed shoulders on the tube ends for connection with another chimney inner tube element, and to a chimney inner tube element manufactured in this way.

State of the art

It is known to produce such chimney inner tube elements from ceramics by extrusion, whereby after cutting the chimney inner tube element to length, shoulderings are cut from the end sections of the tube ends. However, this is only possible with sufficiently thick tube walls. Thick wall thickness has the disadvantage of high weight and associated high material consumption.

The object of the invention is to provide a method in which a chimney inner tube element with formed shoulders for connection to another chimney inner tube element can be manufactured very cheaply, the chimney inner tube element thus manufactured having improved mechanical and thermal properties. The chimney inner tube element thus manufactured has a lower dead weight than a comparable chimney inner tube element extruded according to a known manufacturing method, with the same wall thickness.

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The essence of the invention

This task is solved by a method for producing a ceramic chimney inner tube element with formed shoulders on the tube ends for connection with another chimney inner tube element, according to the invention, the essence of which lies in the fact that the chimney inner tube element, consisting of a material with cavities, is pressed at one end section from the inside outwards, and at its other end section from the outside inwards, along the circumference to approximately half the wall thickness into the shape of a formed shoulder.

Preferably, the chimney inner tube element consists of a material with 50 volume percent voids.

Preferably, the molded inserts are provided with a groove around the circumference for holding the seal.

Preferably, the chimney inner tubular element is made by extrusion.

Preferably, the cavities are formed as channels lying side by side at a distance and extending in the longitudinal direction of the tube.

In another preferred embodiment, the cavities are located between at least two tubular layers arranged concentrically with respect to each other, spaced apart from each other.

Preferably, the tube layers have spacers spaced apart from each other, approximately in a radial direction to the adjacent layer.

Preferably, the chimney inner tube element is made of a ceramic material consisting of a plastic binder and aggregate with a granular structure, the maximum grain diameter of which is approximately 1/10 to 1/4 of the wall thickness of the walls between the cavities/channels.

Preferably, the binder is clay and the abrasive is fireclay.

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Overview of images in the drawing^

The invention is further described and explained in more detail by examples of its embodiment according to the attached drawing, which shows in Fig. 1 the wall of the chimney inner tube element in section, in a perspective view with a formed shoulder, in Figs. 2 to Fig. 5 the walls with different cross-sections, in Fig. 6 the wall in longitudinal section with a formed shoulder, and in Figs. 7 and Fig. 8 two mutually adjacent tube ends of two chimney inner tube elements.

Examples of embodiments of the invention

According to Fig. 1 to Fig. 7, the wall of the ceramic chimney inner tube element 12 has cavities 2, which make up approximately 50% of the total volume of the wall. As the individual figures, with the exception of Fig. 5 and Fig. 6, show, the cavities 2 are formed as channels running at a distance from each other and in the longitudinal direction of the tube. The cavities / channels 2 have a square, rectangular or parallelogram cross-section and are generally arranged offset from each other.

In the exemplary embodiment according to Fig. 4, the wall 1 of the chimney inner tube element consists of several concentrically spaced layers 3, 4, 6, 7, with the outer layers 3 and 4 having spacers 8 running spaced apart from each other in the radial direction to the adjacent layer. The two inner layers 6 and 7 have spacers 8 arranged on both sides.

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In the embodiment according to Fig. 5, the cavities 2 are formed irregularly and distributed over the entire cross-section of the wall i.

In the embodiment shown in Fig. 3, the wall 1 consists of two layers 3 and 4 arranged concentrically with respect to each other, spaced apart from each other.

To produce the formed shoulder, the pipe ends are simply deformed as shown in Fig. 1 and Fig. 6, whereby the compression to half the wall thickness is carried out taking into account half the width of the gap between the parts of the formed shoulder, so that the chimney inner pipe element can be easily assembled. This deformation is possible in a simple way, since only the cavities/channels 2 are compressed, so that only a small amount of force is required. Furthermore, no material has to be removed from the pipe.

In chimney inner tube elements made by extrusion from ceramic materials, a pronounced wall shaping is created parallel to the cavities/channels 2. Therefore, the overmolded end sections have a layered structure due to the pressed, nested channels 2, as shown in particular in Fig. 1 and Fig. 8. This layered structure causes a very high stability of the chimney inner tube element according to the invention.

As shown in particular in Fig. 7 and Fig. 8, the formed shoulder on the pipe ends of the chimney inner pipe element 12 is formed by forming one end section from the inside outwards into a formed shoulder 11, and the other inner section from the outside inwards into a formed shoulder 10. The formed shoulders thus formed may have circumferential grooves 13 for securing the seal, as shown in Fig. 7.

The cavity volume formed axially to the pressing direction or to the longitudinal direction of the tube can be created with any profile. Depending on the desired use

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Φ, the pipe column made of chimney inner tube elements can be subjected to high temperatures. Stationary temperature profiles are generally unproblematic even at temperatures of up to 600 °C. In practice, however, heating rates of up to 50 °C per minute can occur. In the case of previously known chimney inner tube elements, the tensile stresses can therefore overcome the strength of the material due to the relatively poor thermal conductivity and lead to the formation of cracks.

The inventive embodiment with cavities Z channels 2 in the chimney inner tube element according to the invention prevents the propagation of cracks by widening the bottom of the notch. The volume of the cavities / channels can be fully considered as a substitute for coarse fireclay. This has the advantage that a significantly finer grain can be used.

During extrusion, a significant wall shaping is created that runs parallel to the cavities/channels. This leads to an anisotropic lengthening of the vapor diffusion path. This increases the resistance of the element to vapor diffusion compared to a solid element made of the same material.

This shaping also results in a high mechanical stability of the chimney inner tube element according to the invention, especially in the area of the shaped shoulders 10, U, due to the formation of layers of channels pressed into each other, running in the longitudinal direction. The chimney inner tube element according to the invention also has the advantage that only 50% of the material has to be used, which, among other things, leads to a weight reduction of 50%.

If desired fracture points are formed in the radially extending wall regions of the wall 1 of the chimney inner tube element, cracks will occur at these desired fracture points under thermal stress, so that a chimney inner tube element consisting of several layers is formed, similar to the chimney inner tube element consisting of two layers 3, 4 shown in Fig. 3. Such tubes are particularly susceptible to very high thermal stress.

The designed design of the formed shoulders can also result in a smooth pipe both inside and outside, creating favorable conditions for flow.

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Claims (9)

PATENT CLAIMS Method for producing a ceramic chimney inner tubular element with molded shoulder at the pipe ends for connection with another chimney inner tubular element, characterized in that the chimney inner tubular element consisting of a cavity material is internally disposed at its one end section (11) outwardly and at its second end section (10) from the outside inwardly, it compresses about half the wall thickness in the shape of a molded shoulder circumferentially. Method according to claim 1, characterized in that the chimney inner tubular element consists of a material in which 50 percent of the volume is formed by cavities. Method according to claim 1 or 2, characterized in that the molded shoulder (10, 11) is provided circumferentially with a groove (13) for receiving the seal. Chimney inner tubular element according to one of the method claims 1 to 3, characterized in that the chimney inner tubular element (12) is made by extrusion. Chimney inner tubular element according to claim 4, characterized in that the cavities (2) are formed as spaced-apart channels extending in the longitudinal direction of the pipe. Chimney inner tubular element according to claim 5, characterized in that the cavities (2) lie between at least two spaced-apart, concentrically arranged tubular layers (3, 4). · ♦ ·· ♦ · Chimney inner tubular element according to claim 6, characterized in that the tubular layers (3, 4, 6, 7) have spacers (8) extending relative to each other, in approximately radial direction to the adjacent layer. Chimney inner tubular element according to any one of claims 1 to 7, characterized in that the chimney inner tubular element is made of a ceramic material consisting of a plastic binder and a grit having a grain structure whose maximum grain diameter is about 1/10 to 1/4 wall thickness between cavities / channels. The chimney inner tubular element according to claim 8, characterized in that the binder is clay and chamotte grind.