JPS6367076B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention consists of an inner tube and a gas-tight and pressure-resistant outer tube that is thermally insulated on the inside, and the inner tube is connected to the outer tube in a cage. This invention relates to thermally insulated piping for high-temperature gases, such as those mounted on multiple bulbs.

[Conventional technology]

These thermally insulating pipes are used in particular as horizontal straight connecting pipes between gas-cooled nuclear reactors and heat consumers, but they can also be used in a similar manner for non-horizontal pipes. Helium used as a heat transfer medium has a temperature of about 1000°C, a pressure of 40 atmospheres, and a flow rate of 60 m/sec. This type of piping preferably has a heat-resistant inner tube that does not need to be completely airtight, and a gas-tight tube that does not need to withstand the high temperatures of the gas because it is thermally insulated on the inside and cooled from the outside. and a pressure-resistant outer tube.
In the case of high-temperature piping, the individual structural components have to meet very different requirements and therefore have to be made from different materials.
The inner tube must withstand not only high temperatures but also the velocity of the flow medium. It must also be prevented from being damaged by thermal stress.
Materials suitable for these requirements, such as ceramics or graphite, can only be processed as parts of certain dimensions, which cannot be connected to each other in a gas-tight manner at the intended temperature. This inner tube is therefore constructed by combining several cylindrical bodies of a given length with unavoidable radial gaps between them. The outer tube must not only be gas-tight but also pressure-tight and must accept external forces that are the resultant of the weight of the tube and its clamping force. Therefore, for the outer tube, a metal material that has good weldability but only a certain degree of heat resistance is used. For large diameters, the outer tube has to be rolled from sheet steel and welded, which has large tolerances. Thermal insulation placed between the outer tube and the inner tube must on the one hand withstand the high temperatures in the inner tube and on the other hand must direct the locally confined hot gas flow away from the outer tube. A laminated solid body made of elastic fiber material or ceramic material is used here. This elastic material is not suitable for static challenges, and solid thermal insulators interfere with the inevitable relative movement between the inner and outer tubes, so for this type of piping the outer Further elements are required between the tube and the inner tube to support and center the inner tube, but to allow for thermal expansion in the axial and circumferential directions. The main problem with this type of piping is therefore the support and attachment of the inner tube to the outer tube. Elastic metal elements have the disadvantage that they cannot withstand high temperatures and locally transfer large amounts of heat to the outer tube. Ceramic or rigid elements are damaged not by high temperatures but by large temperature differences and cannot accommodate the relative displacements between the inner and outer tubes caused by the different temperatures. This has not hitherto been applied, since elements with rolling bearings cannot bridge the unavoidable large tolerances between the inner and outer tubes and the different radial expansions of both the inner and outer tubes. In this case, for example, if the outer tube with a diameter of 1 m is to be produced economically, it can be rolled from a steel plate.
It is necessary to weld them against each other, so it is necessary to be careful that the shape will not be exactly circular. Machining the inner wall of the outer tube, for example on a lathe, at the desired diameter and length is very difficult and expensive.

[Problem that the invention seeks to solve]

The object of the invention is to provide a thermally insulated pipe of the type mentioned at the outset, free from the above-mentioned disadvantages.

[Means for solving problems]

According to the invention, this object is achieved in the thermally insulated piping for hot gases mentioned at the outset, consisting of a plurality of thin-walled cylindrical bodies, the inner tubes of which are inserted into one another in the axial direction, the cylindrical bodies being A plurality of hand-held heat-resistant balls with a radially adjustable lower range and radially flexible upper ranges are attached to the outer tube and can be slid longitudinally and circumferentially on the inner tube. This is achieved by being supported by a support device.

[Action and effect]

By supporting the inner tube on a plurality of spheres whose position during assembly can be adjusted in the radial direction, each barrel of the inner tube is aligned with the preceding barrel as well as the outer tube during assembly. The small contact surface between the sphere and the inner tube or the outer tube results in very low heat transfer through the support device. Furthermore, the sphere can be made of a high temperature resistant material, for example alumina.

This retaining device preferably has a small cross-sectional area in the vicinity of the inner tube, ie a cross-sectional area that is not favorable for transfer, in order to prevent large amounts of heat from being transferred from the inner tube to the outer tube.

The weight of this inner tube is light, so that the static and dynamic loads on its holding device are reduced. The support device, which is arranged between the inner tube and the outer tube and which slides over the inner tube, is preferably arranged on the upper side, and in particular opposite the aforementioned sphere. This support device flexes radially, on the one hand to allow an unavoidable enlargement of the diameter of the inner tube in the event of high temperatures, and on the other hand to prevent unacceptable movements of the inner tube in the event of shocks or vibrations. must be able to do so.

〔Example〕

Embodiments of the present invention shown in the drawings will be described in detail below.

In FIGS. 1 and 2, one end of the inner tube 1, made of graphite for example, rests on two balls 2 held by a retainer 4 attached to the outer tube 3. ing. The other end of the inner tube 1 is placed in a counterbore of the adjacent inner tube 1 or in a correspondingly formed connection (not shown) at the end of the pipe of the inner tube 1. It's dark. The upper region of the inner tube 1, in particular the part diametrically opposite to the ball 2, is provided with two support devices which can be slid longitudinally and circumferentially on the inner tube 1 and can be deflected in the radial direction. Supported by 5. This support device 5 is guided in a holder 6 attached to the outer tube 3. Furthermore, each inner tube 1 of 2
There is one pin 7 in the cross section that divides the sphere 2 into pieces.
is located. This pin 7, as shown in detail in FIGS. 7 and 8, is attached to the outer tube 3 and fixes the inner tube 1 in the axial direction. In order to protect the material of the inner tube 1 from high local stresses, a pressure ring 8, for example made of alumina, can be arranged between the pin 7 and the hole in the inner tube 1 in which this pin 7 is inserted. .
In order to avoid the need for machining the entire circumference of the inner tube 1, a contact surface 9 is arranged in each case between the support device 5 arranged between the ball 2 and the inner tube 1 and the inner tube 1. . This contact surface 9 is arranged in a corresponding flat hole in the inner tube 1.

3 and 4 show that the ball 2 between the inner tube 1 and the outer tube 3 is held in a holder 4. FIG. A contact face piece 9 made of, for example, alumina is arranged between the ball 2 and the inner tube 1, and a contact face piece 10 made of metal is arranged between the ball 2 and the outer tube 3. During assembly, the radial spacing between the inner tube 1 and the outer tube 3 is adjusted using these contact surfaces 9, 10, and thereby the inner tube 1 is connected to the outer tube 3 and the adjacent inner tube 1. A large number of contact surfaces 9, 10 of different thicknesses must be provided in order to be able to match the contact surfaces 9, 10 of different thicknesses. But ball 2
The spacing between the outer tube 3 and the outer tube 3 can of course also be adjusted by means of a disk (not shown), which is also held by the retainer 4. The three bolts 11 of the retainer 4 are prevented from rotating by bent washers 12 in a well-known manner. outer tube 3
Of course, it is also possible to adopt a welded structure at this location in order to avoid providing a hole.

5 and 6 show the arrangement of the support device 5. FIG. This support device 5 is guided in a holder 6 attached to the outer tube 3 and can be slid radially and circumferentially on a contact surface 9 arranged on the inner tube 1 . The retainer 6 is attached to the outer tube 3 by bolts 11 which, like the retainer 4, are prevented from rotating by bent washers 12. Of course, a welded structure can also be used here. The rotationally symmetric support device 5 has a spherical surface with a large curvature at its end on the contact surface body 9 side, and is supported by the outer tube 3 via a laminated disk spring body 13 . The temperature of this spring body 13 is mainly determined by the temperature of the outer tube 3 to be cooled. Especially when assembling the spring 13
In order to prevent the support device 5 from being compressed to unacceptable dimensions, the support device 5 has a step at its upper end;
The support device 5 is supported by the holder 6 at this step.

7 and 8 show the eccentric pin 7. FIG. The end of this pin 7, which projects into the inner tube 1, and in particular the part which comes into contact with the pressure ring 8 placed in the inner tube 1, has the shape of a ball. The other end of this pin 7 has the shape of a truncated cone whose center is offset eccentrically. This truncated cone part is the outer tube 3
The holding plate 1 is centered by a holding body 14 and correspondingly hollowed out in the form of a cone.
It is fixed by 5. The holding body 14 and the holding plate 15 are fastened together with three short bolts 16 and attached to the outer tube 3 with three long bolts 17. All bolts are prevented from turning by folded washers 12 in a known manner. If the bolts 16 and 17 are not tightly tightened, the eccentric pin 7 will be rotated. The center of the spherical end then traces a circle and in this way an axial adjustment of the inner tube 1 takes place. In this case, the inner tube 1 also undergoes displacement in the circumferential direction, but this does not pose a problem since the inner tube 1 is formed almost rotationally symmetrically. Since the inner tube 1 must be able to expand freely radially with respect to the piping, the pin 7
has a sufficient distance from the inner tube 1 in this direction. The pin 7 is made of a high temperature resistant material, for example alumina, and has a rounded transition between a truncated conical end and a bulbous end, so that no stress concentration occurs there. do not have. The pressure ring 8 shown in FIG. 7 is particularly valuable when the permissible surface pressure of the material of the inner tube 1 is low, such as graphite, for example. This pressure ring 8 can also be omitted if the inner tube 1 is made of a ceramic material with high mechanical strength.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the piping according to the present invention (a cross-sectional view taken along line - in Fig. 2), Fig. 2 is a cross-sectional view taken along - line in Fig. 1, and Fig. 3 is a cross-sectional view taken along line - in Fig. 1 and Fig. 2. 4 is a plan view of the spherical support device shown in FIG. 3 as seen from the inside; FIG. 5 is an enlarged sectional view of the support device shown in FIG. 2; 6 is a plan view of the support device in FIG. 5 as seen from the inside, FIG. 7 is an enlarged sectional view of the pin shown in FIGS. 1 and 2, and FIG. 8 is an inside view of the pin in FIG. 7. FIG. DESCRIPTION OF SYMBOLS 1...Inner tube, 2...Ball, 3...Outer tube, 4...Cage, 5...Support device, 6...Cage, 7...Pin, 8...
Pressure ring, 9, 10... Contact surface body, 14... Holding body, 15... Holding plate.

Claims (1)

[Claims] 1. Consisting of an inner tube and a gas-tight, pressure-resistant outer tube that is thermally insulated on the inside, the inner tube is mounted on a plurality of balls mounted in a retainer of the outer tube. In thermally insulated piping for hot gases, such as those installed in A plurality of supporting devices 5 are supported by adjustable heat-resistant balls 2 and are attached to the outer tube 3 with radial deflection in their upper regions and can be slid longitudinally and circumferentially on the inner tube. 1. A thermally insulated piping characterized in that it is supported in a twisted manner.