EP2496383A1

EP2496383A1 - Method and device for machining a sealing seat of a shut-off valve

Info

Publication number: EP2496383A1
Application number: EP10779273A
Authority: EP
Inventors: Siegfried GÜGEL; Karl-Heinz Herzing; Josef Sprehe; Volker Wurzer
Original assignee: Areva NP GmbH
Current assignee: WURZER, VOLKER
Priority date: 2009-11-04
Filing date: 2010-11-04
Publication date: 2012-09-12
Anticipated expiration: 2030-11-04
Also published as: US20120240403A1; EP2496383B9; WO2011054891A1; DE102009046401B4; CN102596502B; RU2521569C2; JP5499178B2; CA2778164C; PL2496383T3; CN102596502A; DE102009046401A1; BR112012010574B1; JP2013510008A; BR112012010574A2; EP2496383B1; RU2012122829A; CA2778164A1; US8539673B2

Abstract

The invention relates to a method for machining a sealing seat (24a, b), arranged at the end (26) of a connection pipe (8a, b), of a shut-off valve (6) fitted in a power generating or industrial plant (2), which method comprises the following steps: a) an upper valve part (16) and the internal housing fittings (32) are removed from the housing (10) of the shut-off valve (6), whereby a housing opening (14) is exposed, b) a clamping device (40), having a counter-bearing (56), is introduced through the housing opening (14) into the or a further connection pipe (8a, b) and fastened to the inner wall (50) thereof, c) a machine tool (58), having a bearing (64), is introduced into the housing (10) through the housing opening (14) and mounted with its bearing (64) on the counter-bearing (56), d) a machining step (B1-4) is carried out with the machine tool (58) on the sealing seat (24a, b), e) the machine tool (58) is detached from the counter-bearing (56) and removed through the housing opening (14), f) if need be, steps c) to e) are repeated with another or the same machine tool (58), g) the clamping device (40) is detached from the connection pipe (8a, b) and removed through the housing opening (14), and h) the upper valve part (16) and the internal fittings (32) are attached to the housing (10). A device for machining a sealing seat (24a, b), arranged at the end (26) of a connection pipe (8a, b), of a shut-off valve (6) fitted in a power-generating or industrial plant (2) comprises a clamping device (40), which can be introduced through a housing opening (14) of the shut-off valve (6) into the or a further connection pipe (8a, b) and includes a counter-bearing (56) and a fastening element (47) interacting with the inner wall (50) of the connection pipe (8a, b), and at least one machine tool (58), which can be introduced through the housing opening (14) into the housing, for carrying out a machining step (B1-4) on the sealing seat (24a, b), wherein the machine tool (58) has a bearing (64), which can be mounted in the counter-bearing (56).

Description

Method and device for processing a sealing seat of a shut-off valve

The invention relates to a method and a device for processing a sealing seat of a shut-off valve. To shut off pipelines in power plants or industrial plants a variety of shut-off valves are used. As industrial plants come e.g. all fluid equipment, e.g. the chemical industry, in question. For power plants here are all types of power plants such. Nuclear power plants, i. Boiling and pressurized water reactors addressed.

In question shut-off valves are e.g. Gate valves and check valves in low (ND), medium (MD) and high pressure (HD) areas, corresponding to approx. 40bar, 40-160bar and over 160bar. The nominal widths of corresponding shut-off valves are in the range of approx. 50 to 1200mm.

The shut-off valves in this case have at least two connection ^¬ pipes that lead inside a fitting housing. There have such connection pipes with sealing functionality on their front ends sealing seats. These run, for example, to the center plane of the shut-off valve parallel (LP check valve) or in this case to the upper part of the valve opening inclined ^¬ th plane (HD wedge slide).

To close the valves, eg by means of an axial movement of a spindle or a pivoting movement of a non-return valve, Flap sealing elements, such as sealing plates, into the area of the connecting pipes of the valve body, which bear against the sealing seat. For slide gate valves, for example, the pressure-loaded side (inlet connection pipe) of a shut-off valve presses the sealing plate against the sealing ring or sealing seat on the non-pressure side (drain connection pipe). This creates a sealing effect. In the case of shut-off valves, for example, the medium is thereby blocked independently of the direction of flow; in the case of check valves, the media flow is blocked only against a predetermined flow direction.

Gate valves are usually set path-dependent via remote drives or handwheels. The path-dependence of the travel path means that the sealing plates are moved in and out of the valve housing just enough so that they reliably block or release the sealing seat even taking into account all the temperature expansions and do not collide with the valve body. Since the sealing surfaces in corresponding shut-off valves must withstand a high load, these are e.g. Low-pressure valves up to nominal pressure (PN, Pressure Nominal) PN40 secured against wear with a 17% chrome steel armor. In other words, a few millimeters thick layer of chromium steel is welded onto the front end of the connecting pipe as a hard application.

After a certain number of opening and closing cycles of a shut-off valve under operating conditions, a wear ^¬ behavior is due to the partially high surface pressure on the sealing elements, in particular the sealing seats. The sealing behavior of the shut-off valve increases increasing wear of the sealing surfaces and the tightness of the fittings is no longer guaranteed. Depending on the load situation, corresponding wear can already be used after one or several thousand closing cycles. This depends heavily on the type of medium flowing through the valve, the temperatures that occur, etc.

It is therefore necessary to rehabilitate the shut-off valve or their seals with appropriate wear. For the slide assemblies, e.g. the sealing plates, gate valves, check valves, etc., this is easily possible because they can be removed from the valve body and can be rehabilitated outside the valve. The transport of the removed parts is usually unproblematic. The remediation can therefore be e.g. done locally in the plant outside the valve, in a workshop of the plant or at a manufacturer of the valve.

The rehabilitation of the sealing seats of the connection tube is problematic. Access to the sealing seats within the fitting housing is limited. Known is a method for Nachschlei ^¬ fen the damaged sealing surfaces on site with the aid of so-called slider grinding machines, for example, from DD 217 171 AI, DD 278 542 AI, DE 24 00 077 AI and DD 109 822 AI. Here, the upper part of the valve and the internals are removed from the housing of the shut-off valve, creating a

Release housing opening. Through the housing opening, the grinder is manually inserted into the fitting housing ^¬ and the existing sealing seat reground. The material removal takes place here in the micrometer range, so that the plane parallelism of the machined sealing surfaces or housing-fixed sealing seats is restored, as far as this within the scope of the ablation area is possible. Despite the be ^¬ knew regrinding comment on the shut-off valves of operational wear and Ver ^¬ say of components and their internals with increasing service life. Repeated regrinding of damage or general wear is only conditionally possible, namely until a residual armor of a minimum thickness on the sealing seat remains. With increasing grinding, the mixing zone between the base material and the armor, ie the heat-affected zone of the weld, is achieved and the required nominal hardness of the armor is no longer guaranteed. The wear ^¬ behavior of the sealing seat therefore increases proportionally with the number of re-grinding or the time to further and the failure of the sealing elements or sealing surfaces or sealing seats of the shut-off valves adjusts itself.

Since the regrinding takes place only in the ym range and in this case no consideration is given to the absolute dimensions of the fittings, it is possible, for example. a one-sided wear of a diagonally seated sealing seat can not be corrected, which is why the sealing seat angle in the valve body despite reground plane-parallel surface is no longer correct.

Are the fixed in the housing of the shut-off valve

Sealing seats as far damaged that the above-grinding does not create any more remedy, removing the Be ^¬ damage done by cutting out the entire shut-off valve from the piping system. The segregated valve is then provided for refurbishment in a site workshop or a faucet manufacturer, which has the necessary refurbishment machines. The fitting is then clamped in its entirety on the outer surfaces in a jig and through conventional processing machines, such as lathes, welding machines, etc. rehabilitated.

Alternatively, the defective valve is not rehabilitated, but disposed of and introduced at the original location of the piping system in the power plant or industrial plant a new or Aus ^¬ exchange fitting. The cutting out and re-welding ^¬ KISSING a fitting involves considerable expense. In addition, extensive repair specifications are necessary especially for nuclear power plants. The separation of large and heavy valves from the existing pipe system requires special equipment, special lifting equipment and is often possible only with considerable effort due to the cramped environment space of the fitting, for example, first surrounding installation or building parts must be removed in order to remove the fitting at all ,

The transport of the valve within a power plant or industrial plant or to the valve manufacturer is complex and costly. Especially in the nuclear power plant area are the

Faucets contaminated, which leads to additional effort and costs. The handling when removing the fittings is associated with increased risk of injury to the people involved and the risk of damaging the shut-off itself or other components of the industrial plant. When re-welding the fittings balancing pipes are to be made, since the heat-affected zones completely eliminated and cut ^¬ losses have to be compensated. The installation position of the valve must be restored to its original state. If a new shut-off valve used, is expected to significantly increased planning effort since to loading for the new faucet aktu elle ^¬ regulations, such as the Pressure Equipment Directive take into account. Compared with the earlier directives, which are usually many years old, higher security is required. For example, with new shut-off valves, the wall thickness and thus the weight is increased compared to an old valve previously used. As a result, it may be necessary to perform a structure-dynamic calculation of the affected pipeline system or Lei ^¬ tion section, which takes into account the additional weight of the new valve. In the worst case, brackets must be added or reinforced. A lengthy and costly building permit process may be necessary. In addition, due to the performed welds in the pipe system, for example, all pipe sections containing the valve, must be subjected to a new pressure test.

From DE 10 2005 004 232 Al it is also known to carry out a hardfacing on site at a sealing surface. Thus, the surface of the sealing surface can first be brought to a level above the original design specification, which is then finally removed to the repair level.

The object of the invention is therefore to provide an improved method and an improved apparatus for processing a sealing seat one in a power plant or industrial plant Montie ^¬ ren shut-off valve.

The invention is based on the basic idea that

in the installed state in the piping system. The shut-off valve or its valve body remains so mounted in a power plant or industrial plant. With the corresponding On-site remediation procedures can circumvent most of the above-mentioned disadvantageous installation, removal and transport. According to the invention a complex apparatus for that method is used, which is used in the plant for Repa ^¬ temperature of the built-in fitting. The entspre ^¬ sponding sealing seats are only accessible from the housing opening ago when namely fittings Top, drives, sealing plates and other internals are removed. Since the sealing seats are usually approximately parallel, but the housing opening is perpendicular to the center plane of the valve, usually a force and movement deflection must take place by about 90 °. In wedge plate slides the processing apparatus must be adjusted in addition to the angle of inclination of the sealing seats with respect to the spindle longitudinal axis ^¬, that said mid-plane. The lack of space in the valve body requires a special construction ^{¬ way} the processing device, without restricting their functionality. The processing device is to be constructed in a flat construction, in order to be able to be used, for example, between two connecting tubes or sealing seats of a wedge slide. According to the invention, the processing of the sealing seats can thus take place from a direction perpendicular to its transverse plane. The corresponding forces for processing are then particularly easy to apply.

With regard to the method, the object is achieved by a method according to claim 1 for processing a arranged at the end of a connecting pipe sealing seat of a mounted in a power plant or industrial plant shut-off valve, comprising the following steps: In a step a), the upper part of the valve and the installation ^¬ th is removed from the housing of the shut-off valve, whereby a housing opening is released. This housing opening is eg a flange for valves in the low and medium pressure range, for fittings in the high pressure area a housing neck or mandrel. In a step b) is a clamping device through the

Housing opening in the addressed connection pipe or another, for example, the opposite of the sealing seat to be machined connecting pipe introduced. The clamping device is attached to the inner wall of the connection pipe. The Spannvor ^¬ direction has an abutment, which in the assembled state, ie with a fixed clamping device on the

Housing interior facing side of the clamping device is located and thus continues to be accessible from the housing opening.

In a step c), a processing machine is introduced into the housing through the housing opening. The processing ^¬ machine carries a bearing with which it is mounted on the counter bearing. In a step d), a processing step is performed on the sealing seat with the processing machine.

Thereafter, in a step e), the processing machine is released from the abutment and removed through the housing opening. In a step f), if necessary, steps c) to e) are repeated with another or the same processing machine.

After completion of the actual work on the sealing seat in a step g), the tensioning device is released from the connecting pipe and removed through the housing opening again from the shut-off valve. In a step h) finally the Armatu ^¬ renoberteil and the internals are attached to the housing and the valve thereby completes ready for use again. According to the invention therefore, it becomes possible by the clamping device or its thrust bearings and is at the processing machine ^¬ brought stock, to spend the machine tool in a defined position within the fitting housing, and perform targeted from there highly accurate working on the sealing seat. The clamping device or the abutment thus form a geometrically exactly fixed and stationary reference location in the valve, which remains fixed in place for all processing steps or their accuracy. The counter-bearing thus forms a reference point or a reference dimension ^within the valve. This is then fixed relative to the zero dimension of a fitting, for example a flange of a low pressure slide and can be used again during the restoration itself as a zero gauge. In particular, work steps carried out one after the other, for example with different processing machines, can be carried out in positions that are exactly geometrically related to one another, since all processing machines are always stored in a defined geometric position on the fixed abutment which is not moved during the process. The clamping device is thus spent, for example, to any, but fixed position and then determines the position of the anvil in the coordinate system of the valve. The processing then takes place with the processing machines from dimensionally stable from the once fixed position.

It is known to date to exchange a processing head or a work ^¬ convincing a machine. The main body of the machine, eg its drive and housing remain. For example, various turning, drilling or milling heads have been used. According to the invention, however, the entire Bearbeitungsma ^¬ machine is changed. This brings the advantage of every machine for , even for example in respect of the drive motor, the housing, etc., to make individually and optimally for each of the machining ^¬ preparation steps. However, the geometric reference ^¬ position, which is determined by the anvil, then applies to all, however differently designed processing machines.

Since the anvil is fixed in the area of the sealing seat to be machined, the distances to the working area are small. The processing machines used can be stable and easy to carry out what high machining forces made ^¬ light.

The sealing plates or slide assemblies can in the usual way as before outside the fitting housing, e.g. in a workshop, to be repaired.

The method is e.g. qualified in advance to the corresponding dummies of the valves, so that the reproducibility of the fitting to be machined in the system is ensured. In other words, a simulation is done on a pattern, e.g. also to complete examination or admission procedures.

In a preferred embodiment of the method, the end of the connection pipe facing the interior of the housing is turned or ground off as a processing step. By such a step, it is possible, for example, turn off or grind a fit for a newly inserted slide seat ring in a precisely defined geometric plane, remove armor of a sealing seat down to the base material in a defined plane or a newly applied armor both plane-parallel and in one defined Just to grind precisely with respect to the valve geometry. By turning a mechanical finishing of the sealing surfaces can be realized by shaping grinding their fine machining. By the removal of the base material later good networking newly applied material with the base material of the valve or the connection pipe is ensured.

In a further preferred embodiment of the method, a pan ^¬ forming the sealing seat is welded onto the end face of the connecting pipe as a processing step. In particular, in combination of this processing step with the above step, the following procedure is mög ^¬ Lich: In a valve to be renovated after disassembly of the slide assemblies the first still existing or the current state of the seal seat optically or mechanically vermes ^¬ sen. For example, the thickness of the remaining remaining on the connecting pipe armor is measured. Subsequently, the clamping device is attached as described and fixed to a desired position with respect to the fitting geometry, so that, for example, the anvil forms a fixed point at a defined location in the fitting. Then is turned off with a Bear ^¬ beitungsmaschine the sealing seat of the opposite connection pipe down to the base material, then coated with a welding machine or apparatus, as a machine Bearbeitungsma ^¬ a new armor in the original manufacturing size of the sealing seat. The mixture is then again turned off by the rotating device of the sealing seat on the original production size, and finally coplanar finely ground with a GRINDER ^¬ machine. Thus, the exact original sealing surface geometry in the original state, too Regarding the exact geometric position in the fitting, restored.

Thus, with the method according to the invention, a newly incorporated and thus high-quality hardness profile in the form of a new armor or a new sealing seat can be introduced into the existing shut-off valve. For example, hardnesses of 340-400HV (Vickers hardness) are possible. With this method, the service life and the wear behavior are significantly improved due to the newly introduced hardening at the sealing surfaces. Neither the slider itself nor the pipe system in which the slide remains firmly installed, so changes are made. The specification of the valve is not changed since the original state is restored almost identically at the time of manufacture of the valve. The preparation of preliminary test documents is considerably simplified. For example, in a nuclear power plant only repair pre-test documents must be created. The entire effort of welding out and welding in the fitting is eliminated, the system is not changed, does not have to be re-pressed, does not require any new operational testing, static or dynamic calculations. The disposal problem is significantly minimized, since, for example, no old, irradiated Armatu ^¬ rengehäuse must be disposed of.

The machine tool should have degrees of freedom of five axes, namely a displacement in the longitudinal direction of the connection pipe, a tilt towards the sealing seat to follow different angles of wedge slides, a rotation about the longitudinal axis, and the displacement perpendicular to the longitudinal axis (movement in a plane: 2 degrees of freedom). Any desired sealing seats can be processed with this. In an alternative method variant, the machining ^¬ processing step, a sealing seat bearing housing seat ring or separated from the connection tube welded to this. By such a processing step can also restore high-pressure fittings, in which the sealing seat itself can not be rehabilitated on site. The sealing seat is namely applied as a multi-layer layer of particular hardness on a ent ^¬ speaking seat ring. For this purpose, a special workshop is necessary, which allows, for example, a horizontal mounting of the seat ^¬ ring. By the processing step, however, the seat ring is released from the valve. This alone can be spent with significantly less effort in a special workshop and rehabilitated there. After restoration, it is returned to the original fixture. Alternatively, a new seat ring is immediately integrated into the fitting. The remaining valve remains in the system and does not have to be replaced. Again approval process ^¬ usually or other overhead significantly reduced.

In such a processing step, the clamping device is usually introduced into the same connection pipe, which is also to be processed. The clamping device is therefore, for example, further introduced into the connecting pipe than when the low-pressure fitting of the connecting tube opposite sealing seat to be restored. Nevertheless, the clamping device is again as close as possible to the processing location. In a further variant of the method, the tensioning device is fastened in the connection pipe in such a way that a reference point of the tensioning device on the central longitudinal axis of the connection pipe lies. As a result, the above-mentioned geometrically exact or predefined position of the clamping device or the anvil is achieved in the coordinate system of the valve. In the assembled state of the processing machine, if this is held in the abutment, the machine is then always positioned at a known position in the fitting geometry.

With regard to the device, the object of the invention is achieved by a device according to claim 7 for processing a arranged at the end of a connecting pipe

Sealing seat of a shut-off valve mounted in a power plant or industrial plant.

The device comprises a tensioning device, which can be introduced through a housing opening of the shut-off valve into the restoration pipe or another connecting pipe. The clamping device has a counter-bearing and includes a cooperating with the inner wall of the connecting tube mounting ^¬ element to the clamping device safe and stable for the duration of the above method in the connecting pipe to Fixed To ^¬ gene. The apparatus also comprises at least one through the housing opening in the Housing einbringbare Bearbeitungsma ^¬ machine for performing a processing step on the sealing ^¬ seat. The processing machine has a bearing which can be stored in the abutment. The device according to the invention has already been described in connection with the method according to the invention together with its advantages.

In a specific embodiment of the invention has an on against the inner wall of the connecting tube ^¬ approachable hydraulic cylinder the fastener. By one or in particular a plurality of such hydraulic cylinders, the tensioning Device particularly simple and high strength in the connection pipe are attached. The clamping device is in this case usually disc or cylindrical and is fixed in the assembled state with its transverse plane parallel to a transverse plane of the connecting pipe. By one outside the

Shut-off valve leading hydraulic line, the hydraulic cylinders can be remotely controlled. By selectively controlling various hydraulic cylinders, the position of the tensioning device in a transverse plane to the connection pipe can be easily changed when the hydraulic cylinders extend in the mounting state in an approximately radial direction of the connection pipe.

In a further preferred refinement, the tensioning device comprises at least two measuring probes which can be placed on the inside of the connecting tube. By the sensor, the actual position of the clamping device in the connecting pipe can be determined and these are combined in particular together with controllable hydraulic cylinders to a selbstj ustierenden system, so that, for example, the clamping device in the connecting pipe automatically centered to its central longitudinal axis. In other words, self-adjusting probes result from a corresponding regulation.

In a further embodiment of the invention, the counter bearing is a fixable quick release receptacle. The bearing is then alternatively or additionally a roller or ball head. Due to the quick release holder, a processing machine with its bearings can be fastened particularly quickly and easily to the clamping device. A change to another processing machine is then quick and easy. Due to the fixability, the relative position between bearing and counter ^¬ bearing and thus between processing machine and Spannvor- direction are fixed. So then the Bearbeitungsma ^¬ machine is rigidly fixed in the reference frame of the valve to eg

to maintain during a machining step, a defined output ^¬ location for the machine tool or a nes of this gehalte- tool such as a turning tool. By a roll head, the machine only receives a single degree of freedom of mobility, namely to perform a rotational movement about the roll axis. This is particularly desirable, for example, when a processing machine is to be set to the wedge angle of a wedge slide sealing seat and different angles are to be assumed here. A ball head towards ^¬ allows corresponding Verkippungen the Bearbeitungsma ^¬ machine about two axes, but the fixation in a plane, eg in the axial direction of the connecting pipe, is given.

In a further preferred embodiment, the anvil is fixedly arranged on the clamping device and also placed on it such that it can be centered by an adjustment of the clamping device in the connecting pipe on the central longitudinal axis of the connecting pipe. In other words, therefore, the clamping device can always be adjusted in the connecting pipe, that the counter-bearing is centered on the central longitudinal axis of the An ^¬ closing pipe. The counter bearing thus forms a standardized starting point for the respective bearing of a processing machine. In developing the Bearbeitungsma ^¬ machines for example can always be assumed that the warehouse is located to the processing time on the center ^¬ longitudinal axis of the connecting tube. The machining geometry can be set very easily. In a further preferred embodiment, the processing machine in the assembled state of the

Housing protruding, rigid base support, which includes the bearing. A machining head is in turn firmly on

Base support attached so that its angle of inclination to

Basic support does not vary. It follows from such a device that a change of the inclination angle of the machining head ^¬ processing is effected to the sealing seat solely by a tilting of the base support in counter-bearing. This in turn can be easily adjusted from outside the fitting housing, eg manually by means of a jig or a link. In other words, the base support forms a kind of lever which is accessible and operable outside the housing opening and with which the inclination of the machining head can be varied to the sealing seat. This is also suitable to einzustel ^¬ len in a particularly simple manner, the target inclination of the machine and thus the sealing seat with respect to the shut-off valve. In a variant of this embodiment, the processing ^¬ machine is a turning or grinding machine with a state in the assembly ^¬ outside the housing lying drive. The base ^¬ carrier forms a wave arm, which connects the drive with the machining head. The machining head carries a rotating or grinding element rotatable about a rotation axis, the rotation axis having a fixed relative position to the wave arm. So this results in a grinding or. Lathe whose working plane can be adjusted in the assembled state by movement of the shaft arm from outside the valve body. The grinding step in the above-mentioned method can also be carried out, for example, with a conventional slider grinding machine. By turning and grinding of the inventive device, however, a separate grinding machine is generally no longer required in a system, which in turn reduces Gesamtkos ^¬ th maintenance machines. All work can be carried out with the device according to the invention.

In a further embodiment of this variant of the invention the turning or grinding element, for example a turning tool, deliverable as a work ^¬ generating only in radial and longitudinal direction with respect to the rotation axis. The axial and radial engagement position of the tool in the longitudinal direction of the central longitudinal axis of the An ^¬ closing pipe is thus effected by the delivery. The position of the plane of the attack position, however, is achieved by adjusting the wave arm.

In a further preferred embodiment, the processing machine is a welding machine or -anläge, wherein in the assembled state whose supply unit, eg the voltage ^¬ supply and the controller, outside the housing. Within the housing there is a bearing carrier ^having basic ^¬ . On the base support a weldment and a rotatable about a rotation axis welding head are arranged. The axis of rotation is for example perpendicular to the nominal plane of the sealing surface or the central longitudinal axis of the connecting pipe.

In a particularly preferred embodiment, the

Welding machine a TIG orbital welding machine. This offers the advantage that here the distance between

Welding head and workpiece is controlled by the plant itself. The welding system must therefore be exactly centered only with respect to the transverse plane of the sealing seat.

In a further preferred embodiment, the processing machine comprises a holder which can be fastened to the housing opening. For example, a support plate is attached to the flange of a low-pressure fitting or the dome of a high-pressure fitting, in turn, in the support plate, a part of the processing ^¬ machine, for example, the base support or shaft arm, can be fixed. Thus, in the assembled state, the entire processing machine is fixed at least against unintentional release, but usually also in a defined spatial position in the shut-off valve. In particular with overhead mounted shut-off valves, the processing machine is thus securely held in its mounting or working position.

In a preferred embodiment of this variant, the holder allows a change and fixation of the position of the processing machine in the warehouse in the assembled state of the processing machine. This example is in connection with the above-mentioned variation of the angle of attack of a sealing seat of a wedge slider ^¬ useful if, for example, the fixation in a conventional 3 ° or 7 ° tilt position of the working machine or its tool is possible.

For a further description of the invention reference is made to the embodiments of the drawings. 1 shows a low-pressure wedge slide as a shut-off valve, FIG. 2 shows the fitting from FIG. 1 in the disassembled state, FIG. Fig. 3 shows a valve according to FIG. 2 with inserted

Tensioning device and turning and grinding machine,

Fig. 4, the valve of Fig. 3 with a welding machine

5 shows a high-pressure fitting with inserted clamping device and lathe,

6 shows the detail VI from FIG. 5.

Fig. 1 shows a section of a pipe 4 a system 2, in the example of a power plant, representative of any power plant or industrial plant. In the pipe 4 a shut-off valve 6 is integrated, in the example, a low-pressure gate valve. The shut-off valve 6 has as a fixed component two connection pipes 8a, b, via which it is firmly welded to the pipe 4. The connecting pipes 8a, b are part of a housing 10 of the ARMA ^¬ structure 6, which has a flange 12 at a housing opening fourteenth Fig. 1 shows the shut-off valve 6 in the final assembled state, namely, if on the flange 12, a housing cover 16 is mounted, which carries a spindle 18. The spindle 18 terminates at its one end in a hand wheel 20. At the other end of the spindle 18 is a sealing element 22 in the form of two sealing plates. The sealing element 22 cooperates with two sealing seats 24a, b, which are arranged in the interior of the housing 10 at the front ends of the connecting pipes 8a, b. The sealing seats 24a, b are formed such that on the base ^¬ material 34 of the connecting pipes 8a, b an armor 36, in the example of 17% chromium steel at the respective ends 26 is welded frontally. Housing cover 16, spindle 18, hand ^¬ wheel 20 and sealing member 22 together form the so-called housing internals 32 of the shut-off valve 6, which are all removable from the housing 10. In Fig. 1, the shut-off valve 6 is shown in the closed state, that is, the sealing element 22 abuts the sealing seats 24a, b. To open the valve 6, the handwheel 20 is rotated in the direction of arrow 28, whereupon the spindle 18 lifts the sealing element 22 in the direction of the arrow 30 from the sealing seats 24a, b. The ends 26 of the connecting pipes 8a, b are then completely opened and medium, not shown, can flow freely through the pipe 4 in both directions. Through the operation of the shut-off valve 6, the sealing seats 24a, b use heavily. The shut-off valve 6 must be rehabilitated in this regard. According to the invention, the Absperrarma ^¬ tur 6 remains this purpose in the pipe 4. In a first process step a), all housing internals 32 are first removed. Fig. 2 shows the shut-off valve 6 of FIG. 1 with disassembled housing internals 32nd Die

Housing opening 14 is now open, that is, the interior of the housing 10 is accessible from the outside space 44. In addition, the sealing seats 24a, b are visible through the housing opening 14 and can be measured optically or with sliding calipers, not shown, or other measuring devices. Thus, the current state of the sealing seats 24a, b can be determined. In particular ^¬ sondere example, can be determined which thickness d of the sealing seats 24a, b have yet. By operating the Ab ^¬ shutoff fitting 6, the armor 36 has reduced from an original thickness indicated by broken lines do at the time of manufacture of the fitting 6 to the thickness d. For refurbishment of the sealing seats 24a, b will continue to proceed as follows. Through the housing opening 14 is shown in FIG. 3 in a step b) in the direction of arrow 38 a Clamping device 40 mounted in the connecting pipe 8a. The clamping device 40 is approximately disc-shaped and has a stop 42, with which it is placed on the sealing seat 24 a ^¬ . Via a hydraulic line 46 leading into the outer space 44, hydraulic cylinders 48 attached to the clamping device 40 are pressed against the inner wall 50 of the connecting pipe 8a. The hydraulic cylinder 48 is thus part of a fastening element, with which the clamping device 40 in the on ^¬ is secured connection pipe 8a. These are essentially radially movable. As a result, the clamping device 40 is securely fixed in the connecting pipe 8a. In order to center the radial position of the clamping device 40 in the connecting tube 8a exactly on its central longitudinal axis 52, the clamping device 40 also radially outwardly facing sensor 54, by which the distance of the clamping device 40 to the inner wall 50 at the respective position of the sensor 54 are measured can. The hydraulic cylinders 48 are driven accordingly to finally center the tensioning device 40. 3 shows the tensioning device 40 in the end-adjusted mounting state M.

The tensioning device 40 has an abutment 56 which lies in the assembled state M in the interior of the housing 10 or points there and is accessible from the housing opening 14 forth. In addition, a reference point 57, namely the center of the anvil 56 on the central longitudinal axis 52. This serves as a fixed geometric starting position for the bearing 64 to be attached as described below. In a step c) is now in the direction of arrow 38 a

Processing machine 58 also inserted through the housing opening 14 in the housing 10. The processing machine 58 is in Fig. 3, a lathe, which has a shaft arm 62 as the base support 60. On the base support 60 to the abutment 56 matching bearing 64 is firmly attached. Fig. 3 shows the processing machine 58 also in the assembled state M, namely, when the bearing 64 is inserted into the abutment 56 and stored in this. At the, in the assembled state M from the Ge ^¬ housing 10 projecting end of the shaft arm 62, a drive 66 is attached, at the opposite end of the shaft arm 62, a machining head 68. The machining head 68 is rotatable about a rotation axis 74, which to the longitudinal axis 76 of Waves ^¬ arm 62 has a fixed, in the example, a 90 ° angle. A turning tool 78 is held on the machining head 68 as a machining tool or tool, which is deliverable relative to the shaft arm 62 only in the radial direction 80 and in the axial direction 82 relative to the axis of rotation 74. This is achieved by a set screw 84 and a slide valve 86th

On the one hand, the processing machine 58 is fixed or mounted on the housing 10 by the bearing 64 via the abutment 56 and the tensioning device 40 and is pivotable only in accordance with the degree of freedom permitted by the bearing 64 and abutment 56. On the other hand, it is stored at another point. On the flange 12, namely, a holder 70 is screwed, on which in turn adjustably a carriage 72 is mounted, which guides the shaft arm 62.

The sealing seat 24b is to be machined so that its plane plane 88 assumes a predetermined angle to the center plane 90 of the fitting 6, since the shut-off fitting 6 is a wedge slide. In other words, the Bearbeitungsma ^¬ machine 58 is to hire according to the connecting pipe 8b. Since the rotation axis 74 is fixed to the longitudinal axis 76, is the angle is adjusted by moving the carriage 72 in the direction of the arrow 92, and so the shaft arm 62 is tilted in the counter bearing 56. The correct angle is controlled by an inclinometer 94 mounted on the shaft arm 62.

In a method step d), a processing step Bl is now carried out on the sealing seat 24b. By delivery of the turning tool 78 in the radial direction 80 and axial direction 82 namely the remaining armor 36 of the thickness d is turned off from the connecting pipe 8b. Thus, the base material 34 is accessible again for a stable subsequent welding.

In a step e), the processing machine 58 is now released from the abutment 56 and removed through the housing opening 14 against the direction of the arrow 38 from the shut-off valve 6. Since the refurbishment of the sealing seat 24b has not yet been completed, the steps c) to e) are repeated in a step f) correspondingly often with changing processing machines 58.

4, another processing machine 58 in the form of a TIG is now shown in the direction of the arrow 38.

Orbitalschweißmaschine introduced through the housing opening 14 in the housing 10. The processing machine 58 has as ^¬ on its base support 60, a bearing 64, with which it is fixed in the abutment 56. Again, the Grundträ ^¬ ger 60 is again fixed to the bracket 70 to fix the machine ^tool 58 in its mounting position M. This is done by a fixing arm 95. Via a Versorgungslei ^¬ tung 96 of the base support 60 is connected to a space 44 arranged in the outer supply module 98th This contains eg the power source and the controller for the welder. On the base support 60, a weldment 100 in the form of a wire roll, a wire feed 102 and a TIG welding torch 104 is arranged. Via a rotary drive 106 as well as a radial discharge 108 and an axial slide 110, the TIG welding torch 104 is always automatically held at the correct distance from the object to be welded, namely the end 26 of the connecting tube 8b. While shown in Fig. 4 machining step B2 a new armor 36 (indicated by dashed lines) to the on-circuit ^¬ pipe 8b welded. The processing step B2 en ^¬ det when the armor 36 has reached the original thickness do with a certain, serving for a post-processing supernatant. The processing machine 58 is then removed from the housing 10 against the direction of the arrow 38.

It follows a further process step f). According to FIG. 3, the lathe is again used as the processing machine 58. The newly applied armor 36 is turned off with this in a processing step B3 to the original size of the thickness do. The Drehmeisel 78 is then replaced in the processing ^¬ machine 58 by a polishing tool 112 as a tool. With this, the sealing seat 24b tet as a surface of the armor 36 endbearbei ^¬ or polished in a final processing step B4.

Finally, first the machine 58 is ent ^¬ removed. Now, since the machining of the sealing seat 24b has been completed successfully, the clamping device 40 is then released from the housing 10 and ent ^¬ removed in a process step g). If necessary, the clamping device 40 is now inserted into the already processed connecting pipe 8b and in the manner described above, the sealing seat 24a restored to its original dimension of the thickness do.

Fig. 5 shows as an alternative shut-off valve 6 a high-pressure slide, which also has a housing 10 and connecting pipes 8a, b, a sealing element 22, a spindle 18, a hand wheel 20 and a housing cover 16. In contrast to a low-pressure slide, however, a seat ring 114a, b is welded to the end 26 of the connecting pipes 8a, b respectively facing the interior of the housing 10. This carries in each case the sealing ^¬ seat 24 a, b.

The restoration is again the same

Steps as above. In contrast to the above, however, the sealing seats 24a, b are not themselves restored on site, but removed together with their seat rings 114a, b from the fitting 6 and restored or replaced outside. The restau ^¬ or new seat rings 114a, b are then re-welded.

To restore the shut-off valve 6, the entire housing internals 32 (sealing elements 22, spindle 18,

Housing cover 16, etc.) removed, so that a housing opening 14 remains, through which the interior of the housing 10 is accessible ^¬ Lich. According to the procedure of FIG. 3 is a tensioning device is in turn 40 is fully introduced into the interior of the connection pipe 8a which is equipped in accordance with hydraulic ^¬ cylinders 48 and sensors 58 to 52 centered on with ^¬ tellängsachse and to be fixed. In the opposite ger 56 can then again a processing machine 58 is ^¬ sets. The processing machine 58 is also introduced as the ^¬ in the direction of arrow 38 into the interior of the housing 10 and res in the present case in the interior of the Anschlussroh- 8a. In contrast to the above Spannvor ^¬ direction, however, kept in the same connection tube, the sealing seat is to be restored.

Fig. 6 shows the detail VI of Fig. 5. To see is the

Seat ring 114a, which is connected via a weld 116 with the housing 10 and the connecting pipe 8a. The clamping device 40 is supported by the hydraulic cylinders 48 on the inner wall 50 of the connecting pipe 8a. In the counter bearing 56, the processing machine 58 is held with its bearing 64. The processing machine 58 is again a lathe with a turning tool 78 as a tool, which now separates the weld 116. The seat ring 114a may then be released and removed through the housing opening 14. The processing machine 58 is subsequently replaced by a welding unit or machine, not shown, in the form of an alternative processing machine 58, which re-welds a new seat ring 114a or a restored seat ring 114a into the original state shown in FIG. Again, the holder 40 remains permanently clamped during all processing steps and thus forms with their abutment 56 a reference position for docking machine tools 58 to match the corresponding processing steps geometrically exactly to each other. In an alternative embodiment, a degassing slot 118 (shown in FIG. 6) is provided on the seat ring 114a to be newly introduced. Chelt indicated) present, in order to dissipate emerging welding gas during processing.

Fig. 6 also shows, as in a high-pressure sealing seat in the form of a multilayer armor 36 on the seat ring

114a and is not applied directly to the base material 34 of the housing 10 or connecting tube 8a.

Claims

Claims 1. Method for processing a sealing seat (24a, b) arranged at the end (26) of a connecting pipe (8a, b) of a shut-off valve (6) mounted in a power plant or industrial plant 2, comprising the following steps:

a) the upper part of the valve (16) and the housing internals (32) are removed from the housing (10) of the shut-off valve (6), where ^{¬ is released} through a housing opening (14),

b) a clamping device (40) having an abutment (56) is introduced into the or another connecting tube (8a, b) through the housing opening (14) and fastened to its inner wall (50),

c) through the housing opening (14), a, a bearing (64) having processing machine (58) is introduced into the housing (10) and gela ^¬ siege with their bearing (64) on the abutment (56),

d) with the processing machine (58) a processing ^¬ step (Bl-4) on the sealing seat (24 a, b) performed,

e) the processing machine (58) is released from the abutment (56) and removed through the housing opening (14),

f) if necessary, steps c) to e) are repeated with another or the same processing machine (58), g) the tensioning device (40) is detached from the connection pipe (8a, b) and removed through the housing opening (14),

h) the upper part of the valve (16) and the internals (32) are mounted on the housing (10).

2. The method of claim 1, wherein as the processing step (Bl-4) to the interior of the housing (10) facing end side of the connecting pipe (8a, b) is turned off or ground.

3. The method according to any one of the preceding claims, wherein as the processing step (Bl-4) a sealing seat (24a, b) forming armor (36) on the end face of the connection pipe (8a, b) is welded.

4. The method according to any one of the preceding claims, wherein the processing step (Bl-4) is a sealing seat (24a, b) tra ^¬ gender housing seat ring (114a, b) separated from the connection pipe (8a, b) or welded thereto.

5. The method according to any one of the preceding claims, wherein the tensioning device (40) as far into the connecting pipe (8a, b) is inserted until it with a stop (42) on the inside of the housing (10) facing end side of the terminal ^¬ tube (8a, b) is applied.

6. The method according to any one of the preceding claims, wherein the clamping device (40) in the connecting pipe (8a, b) is fixed, that a reference point (57) of the clamping device (40) on the central longitudinal axis (52) of the connecting pipe (8a, b ) lies.

7. A device for processing a sealing seat (24a, b), which is arranged at the end (26) of a connection pipe (8a, b), of a shut-off fitting (6) mounted in a power plant or industrial plant (2).

with a through a housing opening (14) of the shut-off valve (6) in the or another connection pipe (8 a, b) insertable tensioning device (40), which contains an abutment (56) and a fastening element (47) cooperating with the inner wall (50) of the connecting tube (8a, b),

- with at least one through the housing opening (14) insertable into the housing machine tool (58) for imple ^¬ tion a processing step (Bl-4) at the sealing seat (24a, b), wherein the processing machine (58) comprises a bearing (64), which can be stored in the abutment (56).

8. Apparatus according to claim 7, wherein the fastening element (47) includes a against the inner wall (50) of the connecting pipe (8 a, b) approachable hydraulic cylinder (48).

9. Device according to one of claims 7 to 8, wherein the clamping device (40) at least two on the inside (50) of the connecting tube (8a, b) can be applied to the measuring sensor (54).

10. Device according to one of claims 7 to 9, wherein the abutment (56) is a fixable quick release receptacle and / or the bearing (64) is a roller or ball head.

11. Device according to one of claims 7 to 10, wherein the anvil (56) is fixedly arranged on the clamping device (40) such that it by adjusting the clamping device (40) in the connecting pipe (8 a, b) on its central longitudinal axis ( 52) is centered.

12. Device according to one of claims 7 to 11, wherein the processing machine (58) in the assembled state (M) from the housing opening (14) projecting rigid, the bearing (64) carrying the base support (60) and with respect to its inclination to the sealing seat (24a, b) on this fixed machining head (68) so that a change in the inclination angle () of the machining head (68) to a center plane (90) of the shut-off ^¬ fitting (6) by tilting the base support (60) in the abutment (56) is effected.

13. The apparatus of claim 12, wherein the processing machine (58) is a turning or grinding machine, with a in the assembled state (M) outside the housing (10) lying on ^¬ drive (66), and one from the drive (66) a working head (68) reaching, the base support (60) forming the wave arm

(62), wherein the machining head (68) comprises about a rotation ^¬ axis (74) rotatable rotary (78) or sliding element (112) and the axis of rotation (74) has a fixed position relative to the arm shaft (62).

14. The apparatus of claim 13, wherein the rotary (78) or grinding element (112) in the radial (80) and axial direction (82) with respect to the rotation axis (74) is deliverable.

15. Device according to one of claims 7 to 14, wherein the processing machine (58) is a welding machine, with a in the assembled state (M) outside the housing (10) lying supply unit (98), and within the housing (10) lying , the bearing (64) having base support (60) on which a weld stock container (100) and about a rotation axis (74) rotatable welding head (104) are arranged.

16. The apparatus of claim 15, wherein the welding machine is a TIG orbital welding machine.

17. Device according to one of claims 7 to 16, wherein the processing machine (58) comprises a housing (14) attachable mount (70,95).

18. The apparatus of claim 17, wherein the holder

(70,95) in the assembled state (M) of the processing machine (58) allows a change and fixation of the position of the Bearbeitungsma ^¬ machine (58) in the abutment (56).