RU2159689C2 - Method for securing tubes to tube latticed plates - Google Patents

Method for securing tubes to tube latticed plates Download PDF

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Publication number
RU2159689C2
RU2159689C2 RU98122097/02A RU98122097A RU2159689C2 RU 2159689 C2 RU2159689 C2 RU 2159689C2 RU 98122097/02 A RU98122097/02 A RU 98122097/02A RU 98122097 A RU98122097 A RU 98122097A RU 2159689 C2 RU2159689 C2 RU 2159689C2
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RU
Russia
Prior art keywords
pipe
tube
annular
protrusions
cross section
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RU98122097/02A
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Russian (ru)
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RU98122097A (en
Inventor
С.С. Козий
С.И. Козий
Г.А. Батраев
Original Assignee
Самарский государственный аэрокосмический университет им. акад. С.П. Королева
ООО "Ремонтно-механический завод"
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Application filed by Самарский государственный аэрокосмический университет им. акад. С.П. Королева, ООО "Ремонтно-механический завод" filed Critical Самарский государственный аэрокосмический университет им. акад. С.П. Королева
Priority to RU98122097/02A priority Critical patent/RU2159689C2/en
Publication of RU98122097A publication Critical patent/RU98122097A/en
Application granted granted Critical
Publication of RU2159689C2 publication Critical patent/RU2159689C2/en

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28FDETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02Header boxes; End plates
    • F28F9/04Arrangements for sealing elements into header boxes or end plates
    • F28F9/16Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling

Abstract

FIELD: plastic metal working, namely processes for securing tubes to tube plates of heat exchanging apparatuses. SUBSTANCE: method comprises steps of making on outer end portions of tubes annular protrusions with trapezoidal cross section; placing tube in tube opening having annular grooves with rectangular cross section; matching annular protrusions of tubes with annular grooves of tube opening; fixing tube against its possible motion for subsequently securing it to tube plate by applying compression effort to inner surface of tube. Trapezoidal protrusion has large base equal to width of annular groove. Tube is fixed at local expansion of it by inner pressure applied in position of inner annular protrusion for filling with its material volume of annular groove. Tube is simultaneously secured to two tube plates due to placing at both ends of tube cone punches with calibrating portions and moving punches one towards another. EFFECT: enhanced quality of tube joints, namely improved tightness characteristics of joints. 7 dwg

Description

 The invention relates to the field of metal forming, and, in particular, to the processes of fixing pipes in the tube sheets of heat exchangers using the effect of localized directed plastic deformation of the pipe material.

 There is a method of fixing pipes in tube sheets, in which a heat exchange tube is installed in the tube hole, it is fixed from possible axial movement, followed by fixing in the tube sheet by applying normal pressure to the pipe inner surface, for example, by mechanical rolling (see P. Doroshenko. Production Technology for Ship Steam Generators and Heat Exchangers, Leningrad, Shipbuilding, 1972, 143 pp.).

 The main disadvantage of the known method of securing pipes in tube sheets is the uneven residual pressure along the length of the rolling girdle and, as a result, the relatively low service characteristics of the rolling joints. To eliminate this drawback, resort to increased pressure deforming the pipe. The latter causes warping of the tube sheet, extrusion of the tube material in the axial direction due to the angle of inclination of the generatrix of the lateral surface of the roller to the generatrix of the inner surface of the pipe, and therefore a short (increased corrosion) overhaul run of the tube bundle of the heat exchanger.

 There is also known a method of securing pipes in tube sheets, in which the annular protrusions of the trapezoidal cross section are made at the outer ends of the pipe, the pipe is installed in the pipe hole having ring grooves of rectangular cross section, combining the ring protrusions on the pipe with the ring grooves of the pipe hole, fix the pipe from possible movement with its subsequent fixation by applying compressive forces to the inner surface of the pipe - RF patent N 2109589; IPC B 21 D 39/06, Bull. N 12 from 04/27/98 - prototype.

 The disadvantage of this method is the need for multiple rolling, eliminating warpage of the tube sheet, provided that the free volumes of both grooves are filled with volumes of pipe material in the protrusions.

 The objective of the invention is to develop such a method of fixing pipes in tube sheets that would provide increased characteristics of the density of the rolling joints, would not cause warping of the tube sheet, thereby increasing the overhaul distance of the tube bundle of the heat exchanger, and would not require the need for multiple rolling.

 The technical result is achieved by the fact that in the method of fixing pipes in the tube sheets, in which the annular protrusions of the trapezoidal cross section are made at the outer ends of the pipe, the pipe is installed in the pipe hole having ring grooves of rectangular cross section, combining the ring protrusions on the pipe with the ring grooves of the pipe hole , fix the pipe from possible movement with its subsequent fixing in the tube sheet, by applying a compressive force to the inner surface of the pipes , according to the invention, the trapezoidal protrusions are performed with a large base equal to the width of the annular groove, and the pipe is fixed by distributing it locally with internal pressure at the location of the inner annular protrusion, filling the volume of the annular groove with it, and fixing the pipe is carried out simultaneously in two tube sheets by installing both ends of the tube conical punches with gauge sections and messages to the punches oncoming traffic.

 Implementation of the proposed method of securing pipes in tube sheets allows one to obtain milling pipe joints with tube sheets having improved strength and density characteristics, with the possibility of technological control of irreversible deformations of the tube sheet, and not requiring repeated application of the pipe internal pressure deforming pipe.

 This is due to the fact that stage-by-stage deformation of the pipe is carried out, initially causing the introduction of the inner annular protrusion (or the second from the front surface of the tube sheet) into the corresponding annular groove. The final fastening of the pipe in the pipe hole is made by distributing it simultaneously along the entire perimeter of the hole under conditions when the axial load from the tool (in this case, the mandrel) is absorbed by the surface layers of the pipe hole, and therefore is not transmitted to the tube bundle. The latter allows to increase labor productivity by fixing the pipe simultaneously in two gratings. Taking into account the possibility of calibrating the inner diameter of the pipe with gauge belts (for its two ends), uniformity of the application of a deforming force to the inner surface of the pipe at the final stage of its fastening is achieved. The different nature of the application of the deforming force (which leads to a difference in the stress-strain state in individual sections of the milling belt) does not cause increased corrosion of the inner surface of the pipe. On the other hand, the introduction of the outer annular protrusion into the groove of the pipe hole is accompanied by the formation of residual pressure on the lateral surfaces of the annular grooves. Thus, the fastening of the pipe by the combined application of a deforming force to the inner surface of the pipe, in combination with additional O-rings and high-quality filling of the volumes of the annular grooves, predetermines the increased service characteristics of milling joints.

 The invention is illustrated by drawings, where in FIG. 1 shows the assembly of a pipe with a pipe hole before it is fixed at the location of the inner annular protrusion; in FIG. 2 - end of the stage of fixing the pipe with its inner annular protrusion; in FIG. 3 - the initial position of the tool - the mandrel before fixing the pipe at the location of the outer annular protrusion; in FIG. 4 - the initial stage of joint deformation of the pipe and pipe hole with a calibrating tool belt - mandrel; in FIG. 5 - the stage of calibration of the inner diameter of the pipe with a calibrating tool belt - mandrel (with oncoming movement of tools - mandrels); in FIG. 6 - stage of smoothing the inner surface of the pipe when removing the tool - mandrel (when moving the tools - mandrels in opposite directions); in FIG. 7 - milling connection of the pipe with the tube sheet.

 An embodiment of the invention is as follows.

 Heat exchange tube 1 is prepared for assembly with a tube sheet 2, forming annular protrusions of a trapezoidal cross section on the outer surface of its ends (the technology for performing annular protrusions is in accordance with RF patent N 2078636, BI N 13 of 05/10/97). Moreover, the large base of the protrusion is equal to the width of the annular groove. In the hole of the tube sheet 2, annular grooves of rectangular cross section are made. The main condition for choosing geometric dimensions, for example, annular protrusions according to the known geometric dimensions of annular grooves, is the condition that their volumes are equal. The control of the correct installation of the pipe in the pipe hole (coincidence of the protrusions with the annular grooves) is carried out by combining the pipe end with the front surface of the tube sheet (Fig. 1). A tool is introduced into the pipe hole, for example, rolling (one of its three rollers is conventionally shown), and the pipe is fixed (Fig. 2) in the pipe hole by rolling it mainly at the location of the inner annular protrusion. The peculiarity of this stage is that the effect of the rolling roller on the inner surface of the pipe causes plastic deformation of the processed material with the introduction of an internal annular protrusion into the corresponding annular groove and the transformation of the cylindrical generatrix of the pipe opening into a conical one.

 Then, removing the rolling from the hole in the pipe, tools are installed at both ends - mandrels (only one of them is shown for understanding), which are equipped with gauge belts. Axial force is applied to the ends of the mandrels. Distribution of the end of the pipe is performed under conditions when, along with radial pressure on its inner surface, axial loading takes place (Fig. 3). The geometrical dimensions of the mandrel, selected from the condition of compatibility of deformations of the pipe and the pipe hole, provide, in the process of its axial movement, the pipe to be distributed successively to the walls of the pipe hole and then the joint deformation of the connected elements (Fig. 4). As the mandrel passes the pipe in the axial direction, an elastic unloading of the pipe opening is observed behind the gauge belt, leading to a decrease in its inner diameter (Fig. 5). Removing the mandrel from the hole of the pipe (Fig. 6) causes smoothing of its inner surface, leading to stabilization in the structure of the surface layer, because its alternating deformation takes place.

 Regulated power loads, combined with the local nature of the joint deformation of the pipe and the tube sheet, determine both the increased characteristics of the rolling joints (Fig. 7) and the high productivity of the process of fixing the pipe in the pipe hole. The latter significantly affects the cost of production of one dozen compounds.

 A pilot test of the developed method took place when fixing steel (steel 20) pipes with profiled external endings in the tube sheets of steel 16 GS. The initial geometric dimensions of the pipe were: outer diameter - 25 mm, wall thickness - 2.5 mm. The pipe was preliminarily crimped at the ends to a diameter of 23.94 mm. Ring protrusions were obtained by cold extrusion in a floating matrix. With an outer diameter of the annular protrusions equal to 25 mm, the height of the annular protrusions was 0.51 mm (with a depth of the annular grooves of the pipe hole of 0.5 mm), and their base was equal to the width of the annular groove of 3.0 mm. The distance between the protrusions is 10.5 mm. The diameter of the pipe holes was 25.15 mm. The diameter of the pipe hole after the formation of the annular protrusions was 18.4 mm.

 The tooling for the production of pipes with external annular endings and its fastening in the pipe holes was made of U8A tool steel with a hardness of HRC after hardening of at least 56 units and accuracy of executive dimensions according to the 7th grade.

 The formation of annular protrusions on the pipe was carried out on a special hydraulic machine with forces not exceeding 5 mN, which ensured full reproduction of the required geometric dimensions of the annular protrusions of a trapezoidal cross section.

 Fixation of pipes in tube sheets was carried out by rolling of domestic production.

 The pipe was fixed in the pipe hole with the help of mandrels having a diameter of calibrating girdles equal to 19.98 ... 20.0 mm, and driven by hydraulic cylinders.

 It has been established that the formation of ring seals around the entire circumference of the annular grooves with the formation of residual pressure on the contact surface of the annular protrusions with the annular grooves during the quality filling of the volumes of the annular grooves provides guaranteed enhanced service characteristics of the rolling joints; significantly increases the overhaul mileage of the tube bundle, subject to the possibility of repeated use of tube sheets. Tests for pulling the pipe out of the tube sheet revealed that the deforming force of the pipe is limited by the tensile strength of its original section.

 The density of the compounds provided 100% of their suitability for production requirements.

 The corrosion rate on the inner surface of the rolling compound is relatively lower than that of compounds obtained by the known technology-analogue.

 The productivity of fixing 10 pipes in tube sheets is on average 15 ... 20% higher than by the technology reflected in the prototype.

 The invention is applicable in the manufacture of tube bundles of heat exchangers for oil refining, petrochemical, gas and other industries.

Claims (1)

  1.  A method of fixing pipes in pipe holes, in which annular protrusions of a trapezoidal cross section are performed at the outer ends of the pipe, the pipe is installed in a pipe hole having annular grooves of rectangular cross section, combining the annular protrusions on the pipe with ring grooves of the pipe hole, fix the pipe from possible movement with its subsequent fixing in the tube sheet, by applying a compressive force to the inner surface of the pipe, characterized in that the trapezoidal protrusions Pys are made with a large base equal to the width of the annular groove, and the pipe is fixed by distributing it locally with internal pressure at the location of the inner annular protrusion with filling the volume of the annular groove, and the pipe is fixed in two tube sheets simultaneously by installing conical pipes at both ends punches with calibrating sections and messages to punches of oncoming traffic.
RU98122097/02A 1998-12-04 1998-12-04 Method for securing tubes to tube latticed plates RU2159689C2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
RU98122097/02A RU2159689C2 (en) 1998-12-04 1998-12-04 Method for securing tubes to tube latticed plates

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
RU98122097/02A RU2159689C2 (en) 1998-12-04 1998-12-04 Method for securing tubes to tube latticed plates

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RU98122097A RU98122097A (en) 2000-09-20
RU2159689C2 true RU2159689C2 (en) 2000-11-27

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005089975A1 (en) * 2004-03-24 2005-09-29 Quickflange As Method and apparatus for cold joining flanges and couplings elements to pipes

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005089975A1 (en) * 2004-03-24 2005-09-29 Quickflange As Method and apparatus for cold joining flanges and couplings elements to pipes
EA009419B1 (en) * 2004-03-24 2007-12-28 Квикфландж Ас Method and apparatus for cold joining flanges and couplings elements to pipes
US8056208B2 (en) 2004-03-24 2011-11-15 Quickflange As Method for cold joining a coupling element to a pipe
US8474131B2 (en) 2004-03-24 2013-07-02 Quickflange As Apparatus for cold joining a coupling element to a pipe

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MM4A The patent is invalid due to non-payment of fees

Effective date: 20051205