EP2577159B1 - Apparatus for producing inserts for steam generator tubes - Google Patents

Description

The invention relates to a device for producing installation bodies for steam generator tubes. Devices for the manufacture of installation bodies, which are also suitable for steam generator tubes, are for example in documents US2002 / 0011090 A1 . GB748092 A and GB1039490 A disclosed.

A steam generator is a closed, heated vessel or piping system designed to produce high pressure, high temperature steam for heating and service purposes (eg, for operation of a steam turbine). At particularly high steam outputs and pressures such as in power generation in power plants water tube boilers are used, in which the flow medium - usually water - is located in steam generator tubes. Also in the solid combustion water tube boilers are used, since the combustion chamber, in which the heat is generated by combustion of the respective raw material, can be arbitrarily designed by the arrangement of pipe walls.
Such a steam generator in the design of a water tube boiler thus comprises a combustion chamber, the surrounding wall is at least partially formed of tube walls, ie gas-tight welded steam generator tubes. On the flow medium side, these steam generator tubes form, as evaporator heating surfaces, first an evaporator, into which the unevaporated medium is introduced and evaporated. The evaporator is usually arranged in the hottest region of the combustion chamber. He is downstream of the flow medium side, where appropriate, a device for separating water and steam and a superheater, in which the steam is further heated above its evaporation temperature to in a subsequent heat engine such. B. a steam turbine to achieve high efficiency. The evaporator may be preceded by a pre-heater (a so-called economizer) upstream of the evaporator, which uses the feed water by utilizing exhaust gas. or residual heat preheats and so also increases the efficiency of the entire system.

For evaporator heating surfaces in steam generators, smooth tubes or internally ribbed tubes are used. Internally ribbed tubes are used when it is desired to impose a spin on the flow of the flow medium in the steam generator tubes, which causes a higher velocity of the fluid on the inner surface of the steam generator tubes. The use of innenberippten pipes can be required for various reasons, such. B. at a low mass flow density of the evaporator under full load. Even with high heat flow densities (eg in drum boilers), the use of internally ribbed pipes is required: here there is a risk of film boiling, i. h., It forms on the inside of the steam generator tubes, a vapor film, which in contrast to the well-mixed liquid at Blasensieden has a high heat insulating effect. This has the consequence that with constant heat flow density, the wall temperature can rise sharply, which can lead to the destruction of the heating surfaces. Last but not least, a flow stratification during normal load operation can be avoided by internally ribbed tubes (eg, at minimum load in spiral-fed steam generators).

The internal ribbing of the tubes is produced according to the prior art in a cold drawing process. According to current knowledge, internally ribbed pipes can only be produced with materials with a maximum chromium content of 5%. If the use of innenberippten pipes made of higher chromium alloyed steels required, such. B. by a further increase in steam parameters to increase the efficiency, so the innenberippten pipes can not be produced with the currently available processes. In this case, smooth tubes can be provided separately with corresponding spin-generating mounting bodies. These mounting bodies can be made independently of the smooth tubes and thus also of a different material.

The invention is now based on the object to provide a device for producing such mounting body for steam generator tubes, which allows a technically particularly simple manufacturing process and thus a particularly rapid production of mounting bodies.

This object is achieved by the device comprises a winding head with a wire guide pin, a guide opening for a provided with a number of spiral grooves template shaft and a pressure roller, wire guide pin, guide hole and pressure roller are arranged such that in each case a tangent of pressure roller and a Groove of the template shaft and the guide axis of the wire guide pin substantially coincide.

The invention is based on the consideration that a particularly simple production of an installation body could be achieved by using particularly simple materials, in particular simple wire, for the production. To give this wire the correct shape of the mounting body and at the same time to make the manufacturing process particularly simple, the shaping of the wire should be done by means of a template. Due to the elongated, cylindrical shape of a steam generator tube, this template should also have a corresponding shape in the manner of a template shaft. In the template shaft, a negative shape of the mounting body is introduced in the form of grooves, so that the manufacture of the mounting body can be done by mere molding. In order to perform this molding in an integrated process, a winding head should be used, which comprises a wire guide pin for feeding a wire, a guide shaft for the template shaft and a pressure roller for bending the wire. In this case, these components should be arranged such that the wire is guided tangentially into a groove of the template shaft through the wire guide pin. At the same time, a likewise tangentially arranged pressure roller should cause the wire to be pressed into the groove. The device comprises a rotary drive associated with the template shaft and a guide nut arranged coaxially with the guide opening. The thread of the guide nut engages in the spiral grooves of the stencil shaft, so that an automatic feed of the stencil shaft is achieved by the winding head by the rotation of the stencil shaft by its associated rotary drive in connection with the supply of wires to the grooves. The winding head can therefore be fixed rigidly in the device when the wires are fed. This allows a particularly simple production of the mounting body.
Depending on the requirement, the desired grooves in the template shaft can be manufactured individually, for example by means of a cutting production (number, pitch, dimensions). Depending on the desired profile of the installation body to be produced, the grooves can be configured as a helix with virtually any desired number. In the case of a multiply wound helix, all grooves present in the template shaft should be able to be covered with a wire in one operation, so that particularly rapid production of the installation body is possible. For this purpose, the winding head advantageously comprises a plurality of wire guide pins and pressure rollers. In this way, several grooves can be occupied at the same time during the movement of the stencil wave through the winding head with wires.
For a particularly low susceptibility to repair of the device, the moving parts should always be easy to communicate in common. This concerns in particular the feeding of the wires as well as the guidance of the template shaft in the winding overhang. A particularly easy common leadership is possible by a permanent, adequate supply of a lubricant, such as oil is guaranteed. For this purpose, the winding overhang comprises in an advantageous embodiment a lubricant supply device associated with a wire guide pin and / or the guide opening.

For even better control of the manufacturing process, the winding head advantageously comprises a drive device associated with a wire guide pin. On the one hand, this allows a controlled feeding of the wires through the wire guide pins, on the other hand, the automatic forward movement of the template shaft is better supported.

In an advantageous embodiment, such a device for supplying the wires to the grooves in a method for producing a mounting body for a steam generator tube, in which a number of wires with the formation of the mounting body the grooves of a stencil shaft feeding and fixed there, is used.

In an advantageous embodiment, an installation body produced by the method described above is used in a steam generator tube or such a steam generator tube in a steam generator.

The advantages achieved by the invention are in particular that the preparation of an installation body in a steam generator tube by means of a device with a winding head is now a particularly simple, fast and inexpensive technical solution. When using an installation body, internally ribbed pipes can be produced from steels which are alloyed with higher chromium and which are suitable for particularly high steam parameters and thus for a particularly high efficiency of a steam generator. The production of the mounting body is inexpensive, since the stencil shaft can be used for the production of the next mounting body. The significant cost advantages over cold drawn, inner fin tubes also make the use of structural bodies attractive for materials with less than 5% chromium.

FIG 1

eine Schablonenwelle zur Ausführung des erfindungsgemäßen Verfahrens,

FIG 2

eine vergrößerte Darstellung der Schablonenwelle im Schnitt,

FIG 3

einen Wickelkopf mit eingeführter Schablonenwelle,

FIG 4

ein Schnittbild durch den Wickelkopf nach FIG 3, und

FIG 5

schematisch einen Durchlaufdampferzeuger in Zweizugbauweise.

The invention will be explained in more detail with reference to a drawing. Show:

FIG. 1

a template shaft for carrying out the method according to the invention,

FIG. 2

an enlarged view of the template shaft in section,

FIG. 3

a winding head with inserted template shaft,

FIG. 4

a sectional view through the winding head after FIG. 3 , and

FIG. 5

schematically a continuous steam generator in Zweizugbauweise.

Identical parts are provided with the same reference numerals in all figures.

FIG. 1 shows a stencil shaft 1, which is provided in a main region 2 with spiral circumferential grooves 4. The grooves 4 are in this case arranged in the manner of a triple helix around the cylindrical body of the template shaft 1. Depending on the desired profile of the installation body to be produced, the grooves 4 can also be configured as a double helix or a simple spiral. Depending on the requirements, the desired grooves 4 can be made individually, for example by means of a machining operation (number, pitch, dimensions). The length of the main area 2 of the template shaft 1 is slightly longer than the smooth tube into which the installation body is to be introduced. The main area 2 of the template shaft 1 is adjoined in the axial direction by a connection area 6, which is not provided with grooves 4 and serves to handle the template shaft 1 during the method according to the invention.

FIG. 2 shows the stencil shaft 1 in section in an enlarged view. At the interface 8, the profile of the introduced into the template shaft 1 grooves 4 can be seen. The Grooves 4 have a conical profile. Such a profile allows a simpler joining and reverse rotation of the template shaft 1 in the manufacturing process of the non-illustrated mounting body for a steam generator tube.

FIG. 3 shows a device 10 for producing a mounting body for a steam generator tube. The device 10 comprises a substantially cubically shaped winding head 12 in that wires 14 are formed in the grooves 4 of the template shaft 1 and thus form an installation body. The stencil shaft 1 is guided in a guide opening 16, wherein a coaxial with the guide opening 16 arranged guide nut 18 engages in the grooves 4 of the template shaft 1, so that by the rotation by a rotary drive, not shown, which acts on the stencil shaft 1, this through the winding head 12 is moved forward.

The winding head 12 comprises four cylindrical wire guide pins 20, so that four wires 14 can be introduced simultaneously into the grooves 4 of the template shaft 1 in one operation. For an optimum operation of the winding head 12 is optimized to the geometry of the template shaft 1: The central axes in the wire guide pins 20 are arranged tangentially to the grooves 4 of the template shaft 1.

FIG. 4 shows a section through the winding head 12 along a central axis of a wire guide pin 20. The bending of the wires 14 around the stencil shaft 1 is effected by pressure rollers 22, which are also arranged tangentially to the central axis of their respective associated wire guide pin 20 and a groove 4. The strength of the pressure exertion of the pressure rollers 22 is adjusted in each case via an adjusting screw 24 in a Einstellgewinde 26, wherein the adjusting screw 24 is fixed in the axial direction by an adjusting plate 28. Good guidance of the template shaft 1 and the wires 14 is ensured by lubricant supply means, not shown.

The continuous steam generator 110 according to FIG. 5 is in standing construction and designed as a two-pass steam generator. It has a surrounding wall 112, which merges into a funnel-shaped bottom 114 at the lower end of the first throttle cable formed by it. Surrounding wall 112 is constructed of evaporator tubes 116 in a lower region or evaporator region and superheater tubes 116 'in an upper region or superheater region. The evaporator tubes 116 and the superheater tubes 116 'are gas-tightly connected to each other at their longitudinal sides, for example, welded. The bottom 114 comprises a not shown discharge opening 118 for ash.

The evaporator tubes 116 of the surrounding wall 112, which can be flowed through from below through a flow medium, in particular water or a water-steam mixture, are connected with their inlet ends to an inlet header 120. On the outlet side, the evaporator tubes 116 are connected via a Wasserabscheidesystem not shown in detail on the flow medium side subsequent superheater tubes 116 '.

The evaporator tubes 116 of the surrounding wall 112 form an evaporator heating surface 122 in the section of the gas flue located between the inlet header 120 and the water separation system. Connected thereto is a afterheater or superheater heating surface 124 formed by the superheater tubes 116 '. In addition, in the second, of the hot gases downstream flowed through the throttle cable 126 and the heating cable connected to the first throttle cable 128 further, only schematically illustrated heating surfaces 130, such as an economizer and convective Überhitzerheizflächen arranged.

At the bottom of the perimeter wall 112, a number of fossil fuel burners are mounted in each opening 132 of the perimeter wall 112. In FIG. 5 four openings 132 are visible. At such an opening 132, the evaporator tubes 116 of the surrounding wall 112 are curved to bypass the respective opening 132 and run on the outside of the vertical throttle cable. These openings can also be provided, for example, for air nozzles.

Through the use of internally ribbed steam generator tubes with built-in bodies produced in the steam generator 110 by means of the device 10, it is also possible to use steels with a chromium content of more than 5% for the production. Such steam generator tubes are suitable for particularly high steam parameters and thus enable a particularly high efficiency of a steam generator.

Claims (4)

1. Apparatus for producing inserts for steam generator tubes, having a winding head (12) with a wire guiding pin (20), a guiding opening (16) for a former shaft (1) provided with a number of spiral slots (4), and a pressure roller (22), wherein the wire guiding pin (20), guiding opening (16) and pressure roller (22) are disposed such that a tangent of pressure roller (22) and a slot (4) in the former shaft (1) as well as the guiding axis of the wire guiding pin (20) essentially coincide,
   characterised in that
   the apparatus also comprises a rotary drive assigned to the former shaft (1) and a guide nut (18) disposed coaxially with respect to the guiding opening (16).
2. Apparatus according to claim 1, wherein the winding head (12) comprises a plurality of wire guiding pins (20) and pressure rollers (22).
3. Apparatus according to one of the preceding claims, wherein the winding head (12) comprises a lubricant supplying device assigned to a wire guiding pin (20) and/or the guiding opening (16).
4. Apparatus according to one of the preceding claims, wherein the winding head (12) comprises a drive device assigned to a wire guiding pin (20).

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