RU2380640C1 - Heat exchanger manufacturing method - Google Patents

Abstract

FIELD: heating systems.

SUBSTANCE: manufacturing method of heat exchanger containing bank of zigzag-shaped heat exchange tubes with external helical finning, which is installed in housing, consists in arrangement of internal tube inside external one and their combined bending; intensifier is arranged on internal tube; intensifier-retarder with thickness which is not less than thickness of internal tube wall is placed in cavity of internal tube throughout its length with proper bearing; at that, intensifier is removed from internal and external tubes at bending point, and bends are made consequently throughout the length of heat exchange tube.

EFFECT: excluding microcracks when making bends.

3 dwg

Description

The invention relates to a heat exchange technique and is intended to be used as a technological method for manufacturing a highly heat-charged heat exchanger (TO) of a modular type of a nuclear power plant (NPP) operating on a liquid metal coolant under variable load conditions.

A known method of manufacturing a heat exchanger of the type "pipe in pipe" by pre-forming turbulizing elements and installing them in the form of a package in the inner pipe and in the annular space with the formation of transverse fins, and the turbulizing elements form two sizes corresponding to the cross section of the inner pipe and annular space, rigidly fixed them on the inner pipe on both sides with the formation of the package, which is then introduced into the outer pipe, and in the manufacture of turbulizing elements and sintered metal package fastened to the inner tube by sintering under reducing conditions [1].

The disadvantage of this technical solution is the increased vibration of the package of turbulizing elements together with the inner pipe in the outer pipe, as this will be facilitated by the movement of liquids due to the turbulators. Due to the fact that mixing chambers for moving liquids are not provided, a temperature scan will take place along the cross section of the pipe walls. These aforementioned disadvantages lead to damage to the heat exchanger tubes with subsequent destruction, leading to inter-circuit leaks, confirmed by operating experience.

A known method of manufacturing a heat exchanger of the type "pipe in pipe" by installing in the pipe a Central rod with a screw rib, and the screw rib is made with an outer diameter equal to the inner diameter of the outer pipe, and a symmetrical stepped profile with a wide section adjacent to the rod, then on the protrusions between in areas winding a tape having a width equal to the distance between the narrow sections of the ribs and sealing the joints with the formation of a cylindrical pipe, after which the resulting assembly is placed in the outer pipe, tape made of copper foil provided on both sides of the projections [2].

The disadvantage of this technical solution is the relatively narrow scope with the insufficiently required operational reliability of the TO design as a whole, since the use of copper in the channels of heat transfer pipes should be excluded due to the fact that the presence of copper leads, even in the absence of oxygen, to corrosion damage to the walls of the heat transfer pipes , and insufficiently intense heat transfer will entail an increase in weight and size parameters.

The technical result of the invention is the simplification and reliability of the technological process of manufacturing TO modular type to obtain the small dimensions of the latter by increasing the uniformity of the temperature field in the cross section of the tube bundle and reducing the relative deformation of the pipes at temperature elongations.

The specified technical result is achieved by the fact that in the method of manufacturing a heat exchanger containing a bundle of heat-exchanging tubes of a zigzag shape with an external screw finning, which consists in placing the inner pipe inside the outer one and bending them together, an intensifier is wound around the inner pipe along the entire length an inner pipe with a snug fit, an intensifier retarder with a thickness of at least the thickness of the wall of the inner pipe is placed, moreover, at the bend, first from the inside and onto gun pipes, the intensifier is removed, and bends are performed sequentially along the length of the heat transfer pipe.

The essence of the invention is illustrated by drawings, where: in figure 1 - THEN when carrying out the first two bends with the display of the intensifier-retarder, the inner and outer pipes, as well as bending rollers;

figure 2 is a transverse section aa of figure 1;

figure 3 is a sequence of participation of bending rollers in bends TO.

For the method of manufacturing a heat exchanger, the following elements are required: inner tube 0 with an intensifier in the form of a rib 1 on the outer surface, inside which an intensifier-retarder 2 is installed, an outer tube 3 with an intensifier in the form of a rib 4 on the outer surface and bending rollers 5, 6, 7, 8, 9, 10.

A method of manufacturing THAT is as follows.

An intensifier-retarder 2 with a thickness of at least the thickness of the wall of the inner tube 0 is placed in the cavity along the entire length of the inner pipe 0, and the increase in the thickness of the intensifier-retarder 2 is limited by the passage section of the cavity of the inner tube 0. Further, the inner tube 0 is placed in the cavity of the outer pipe 3, but previously from the inner pipe 0 at appropriate intervals in the places of the supposed bend remove the rib 1. In addition, from the outer pipe 3 also in the places of the supposed bend through the same intervals They add a rib 4. All elements of the heat exchanger are fixed at one end so that during bending, the movement of elements relative to each other occurs in the same direction. Section L removal of ribs 1 and 4 is determined from the conditions for bending for one pipe, and bends are carried out sequentially along the length of TO.

The application of the technological method of manufacturing the design of the heat exchanger of the proposed type eliminates the appearance of microcracks during bending, vibration of the heat exchanger elements during operation, will increase the heat transfer intensity, as well as the operational reliability of the structure as a whole.

Information sources

1. Cherednikov N.S. and others. A method of manufacturing a pipe-in-pipe heat exchanger. SU. A.S. N 1011994. F28D 7/10. Priority - 04.16.63. Publ. Bulletin of inventions N 14, 04/15/1983 - analogue.

2. Asakavichus J.P. and others. A method of manufacturing a pipe-in-pipe heat exchanger. SU. A.S. N 1636679. F28D 7/10. Priority - 05.23.88. Publ. Bulletin of inventions N 11, 03.23.91 - prototype.

Claims (1)

A method of manufacturing a heat exchanger containing a bundle of zigzag-shaped heat exchanger tubes with an external screw finning installed in the casing, comprising placing the inner pipe inside the outer one and bending them together, characterized in that an intensifier is wound onto the inner pipe along the entire length of the inner pipe with a snug fit place the intensifier-retarder with a thickness of not less than the wall thickness of the inner pipe, and in the place of bending, first from the inner and outer pipes, I remove the intensifier and the bends are performed sequentially along the length of the heat exchange tube.

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