RU2772005C1 - Method for group extraction of studs of flange connections of nuclear power plants by means of a device for group extraction of studs of flange connections - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: group of inventions relates to a method for group extraction of studs of flange connections of nuclear power plants by means of a device for group extraction of studs of flange connections. The method involves installing a lid with mounting holes on the reactor or steam generator housing, screwing studs with mounting threads and technological threads through the mounting holes of the lid to a certain depth into the reactor housing, while spherical washers are installed on the mounting thread of the studs and crown nuts are screwed with a certain torque with the crown nut wrench, then on the technological thread of the studs the threaded rods are screwed all the way into the end of the studs, next, a support mechanism with a hydraulic power mechanism installed on it is installed on the lid through the threaded rods and crowned nut wrenches, and spherical washers are put on the outer thread of threaded rods and thrust nuts are screwed with a certain torque, absolute elongations of the size of the studs are monitored, after which the hydraulic power units are supplied with the pressure of the working fluid and produce group extraction of studs, fixing and bringing the values of the absolute elongations of the studs to the design value. After that, each hydraulic power unit is pressed with the necessary pressure, crown nuts with a certain torque are turned with crowned nut wrenches, pressure is relieved in the hydraulic power units, after which the device for group extraction of studs from the lid is dismantled. The control of the values of stud extraction is carried out by manually installing each reference pad with a control surface all the way to the base pad and the cylindrical surface of each threaded rod with horizontal alignment in the same plane with the end surfaces of the studs and fixed to the specified surfaces of the threaded rods by means of magnets, while measuring rods of pulse sensors are installed on the control surfaces of the reference pads with the necessary tension linear displacements of the measuring system for measuring the group extraction of studs, built on the basis of pulse counters from linear displacement sensors, a personal computer and a data output device, and the hydraulic power unit is performed containing a hydraulic cylinder with an immersion piston, through which the pistons of the hydraulic power unit are returned to their original position.

EFFECT: possibility of performing work in conditions of high crowding of flange connections, increasing the accuracy of measuring the elongation of studs, reducing the duration of the process of stud extraction by digitizing the control of stud elongation, reducing the number of maintenance personnel, reducing the absorbed dose of γ-radiation of the maintenance personnel during nuclear fuel recharge operations and repair of a nuclear reactor.

3 cl, 9 dwg

Description

Claimed group of inventions: a method of group drawing of studs of flange connections of nuclear power plants and a device for group drawing of studs (UGVSH) of flange connections relate to mechanical engineering, namely to the installation, maintenance and repair of flange connections on the vessels of reactors and steam generators (SG) of nuclear power plants ( NPP) nuclear shipbuilding facilities and floating nuclear power plants.

The invention relates to a method for tensioning a stud, and in particular, to a method for determining the absolute elongation of a stud when the load reaches the design value.

Reactor and SG vessels have large circumferential flanges, on which covers are fixed with nuts and studs. There can be more than 50 such studs and nuts (sets), with a stud diameter up to 140 mm. Each stud may have an internal measuring rod, the end of which may be the reference surface when measuring the elongation of the stud. Measuring the elongation of each pin up to 1 mm long and with a tolerance of ±10 microns is used to control the correct tightening of each pin and minimize possible operator error, while the working force in each hydraulic power unit of the hood can reach 325 tf.

The absolute elongation of each stud is determined by measuring the length of the stud with a measuring rod inserted into an axially extending hole in the stud before and then after the tensile load. The elongation of the stud is determined by the difference in the measured lengths.

Other methods of tightening the studs may be used, but may have small but unacceptable inaccuracies.

A known method of tensioning the pin and determining the elongation of the stretched pin according to the patent dated January 2, 2001 US No. 6.167.764.B1. The hydraulic tensioner is attached to the studs located on the body. The tensioner hydraulic fluid pressure is increased from the first low pressure to a higher pressure to elongate the stud, the increase in hydraulic fluid pressure is either related to the volume of hydraulic fluid, at least in part of the tensioner, or to the displacement of the tensioning element, at least in part increase in pressure. The nut is tightened on the stud. The hydraulic fluid pressure decreases from a higher pressure to a second low pressure, wherein the reduction in hydraulic fluid pressure is correlated with either the volume of hydraulic fluid in the tensioner or the displacement of the tensioner. The stud elongation is then determined as a function of either the difference in relative hydraulic fluid volumes or the correlated difference in tensioner displacement at the first and second low pressures. Finally, the tensioner is removed from the studs.

Disadvantages:

- to implement the method, the device for group drawing of studs must pass metrological certification with the development of graphs of the correlation of the pressure of the hydraulic fluid with a change in its volume and displacement of the tensioning element;

- according to this method, the stud, rod and connecting nut are simultaneously stretched, which creates errors in determining the amount of the stud itself stretching, which is set by the designer of the reactor or SG;

- the need to include additional instrumentation in the hydraulic circuit of the UGVSH - a pressure indicator and a flow meter.

At Russian shipbuilding and ship repair plants, the method of group drawing of studs using UGVSH is widely used. A cover is installed on the reactor vessel or SG, through the mounting holes of which studs are screwed to a certain depth into the reactor vessel or SG, and spherical washers are installed on the fastening thread of these studs and castellated nuts are screwed with a certain torque. Then the threaded rods are screwed onto the technological thread until it stops at the end of the studs, and the keys for tightening the castle nuts are installed on the castle nuts of the flange connection through the threaded rods, then the support mechanism is installed on the reactor cover through the threaded rods and the keys for tightening the castle nuts. mechanism. A spherical washer is put on the external thread of the threaded rod and a thrust nut is screwed with a certain torque, while a composite rod is inserted into the inner channel of each threaded rod, resting on one side in the stud core, and the other, spring-loaded part of the rod, contacts with the measuring rod of the hour indicator type (IC) mounted on the upper ends of the threaded rods. After that, each ICH is manually reset, the pressure of the working fluid is applied to the hydraulic power units, and the studs are grouped out. The values of the absolute elongations of the studs are visually fixed and brought to the design value, after which, each hydraulic power unit is pressed with the necessary pressure, the castellated nuts are tightened with a certain torque, the pressure in the hydraulic power unit is released, and the UGVSH is dismantled from the surface of the reactor cover.

Disadvantages:

- using this method, the accuracy of measuring the elongation of the stud is reduced, since the measurement circuit includes a composite rod about 1.5 m long, resting on one side in the stud core, and the other spring-loaded part of the rod is in contact with the displacement sensor of the IC indicator;

- setting each sensor of the ICH indicator to "zero" and constant visual control over taking readings of the elongation of all the reactor or SG pins, as well as the necessary pressure adjustments in the hydraulic power units determine the composition of the crew of the UGVSH operators in the amount of 4-5 people.

A device for drawing studs of flanged joints according to utility model to patent No. RU 194920 is known, containing a support mechanism consisting of support and tension rings, while the support ring is made with grooves for installing drive elements of keys for rotating the studs, a hydraulic power mechanism having hydraulic cylinders for for supplying the working fluid from the pneumohydraulic unit, each of which is made with a piston having a hole for the traction threaded element for threading onto the ends of the studs of the flange connection, and a system for supplying the working fluid. Each hydraulic cylinder is made single-stage and contains a housing with a system of channels. A spring shock absorber is installed on the hydraulic cylinder piston, and the working fluid supply system includes a distributor connected by hoses to a system of channels in the hydraulic cylinder housing and a pneumatic unit, while each traction threaded element is equipped with a nut, and a displacement sensor is installed at the end of the threaded rod.

Disadvantages:

- the dimensions of single-stage hydraulic cylinders in the horizontal plane limit the possibility of working on flanged connections with high shading at high stud pulling forces;

- dimensions of spring shock absorbers in the horizontal plane limit the possibility of working on flanged connections with high shading;

- decrease in the accuracy of measuring the elongation of the stud, since the scheme for measuring elongations on this device includes the elongation of the stud and the threaded rod;

- setting each sensor of the ICH indicator to "zero" and constant visual monitoring of taking readings of the elongation of all pulled-out studs, as well as the necessary pressure adjustments in the device, determine a significant number of maintenance personnel.

UGVSH is known according to patent No. 2458782 RU, containing a support mechanism with a hydraulic power mechanism installed on it, interacting with threaded rods mounted on studs, and a mechanism for tightening nuts. The support mechanism is made in the form of tension and support rings, and the power mechanism is in the form of multi-stage hydraulic cylinders with at least two steps in each, located along the perimeter of the support ring. The pistons of hydraulic cylinders have holes for threaded rods and their ends rest against each other. The support ring is made with grooves at the ends for installing the keys of the nut tightening mechanism. The control of the amount of drawing of the studs is carried out using displacement sensors installed on the upper ends of the threaded rods. In the support ring, shock absorbers are installed, evenly spaced along the circumference, consisting of blocks of disk springs and designed to return the pistons of the hydraulic cylinders to their original position after the process of drawing the studs is completed.

Disadvantages:

- the dimensions of shock absorbers, consisting of blocks of disk springs, limit the possibility of working on flanged connections with high shading;

- decrease in the accuracy of measuring the elongation of the stud, since the scheme for measuring elongations on this device includes the elongation of the stud and the threaded rod;

- setting each displacement sensor to "zero" and constant visual control of taking readings of elongation values of all pulled-out studs, as well as the necessary pressure adjustments in multi-stage hydraulic cylinders during the working process determine a significant number of maintenance personnel.

The closest in technical essence to the claimed method and device for group drawing of studs of flange connections is a device for drawing studs according to RF patent No. 2458782 and a method for group drawing of studs using UGVSH at Russian shipbuilding and ship repair plants.

The objective of the present invention is to create a method for group drawing of studs of flange joints under conditions of heavy crowding, including a measuring system for measuring the group drawing of studs, built on the basis of pulse counters from linear displacement sensors, a personal computer and a data output device, as well as devices for its implementation.

The implementation of the present invention will allow to obtain a technical result in the form of the possibility of performing work in conditions of large tightness of flange joints, increasing the accuracy of measuring the elongation of the studs, reducing the duration of the process of drawing the studs by digitizing the control of the elongation of the studs, reducing the number of maintenance personnel, and reducing the absorbed dose of gamma radiation of the maintenance personnel during operations of nuclear fuel recharging and repair of a nuclear reactor.

EFFECT: method of group drawing of studs of flange connections of nuclear power plants by means of UGVSH flange connections, containing a support mechanism with a hydraulic power mechanism installed on it with hydraulic power units, each of which is made in the form of multistage hydraulic cylinders with pistons, threaded rods for screwing studs, wrenches for tightening castellated nuts, including installation of a cover with fixing holes on the reactor or steam generator vessel, screwing through the fixing holes of the cover to a certain depth into the reactor vessel, studs having a fixing thread and process thread, while spherical washers are installed on the fixing thread of the studs and screwed with a certain castle nuts with torque, then threaded rods are screwed onto the technological thread of the studs until they stop at the end of the studs, then a support mechanism with with a hydraulic power mechanism installed on it, and spherical washers are put on the external thread of the threaded rods and thrust nuts are screwed with a certain torque, absolute elongations of the stud drawing value are controlled, after which the pressure of the working fluid is applied to the hydraulic power units and the studs are grouped, fixed and bring the values of the absolute elongations of the studs to the design value, after which each hydraulic power unit is pressed with the required pressure, the crown nuts are tightened with a certain torque with wrenches for tightening the nuts, the pressure in the hydraulic power unit is relieved, after which the UGVSH is dismantled from the cover, and control the values of the drawing of the studs are carried out by manually installing each reference platform with a control surface until it stops on the base platform and the cylindrical surface of each threaded rod with alignment horizontally in the same plane with the end surfaces and studs and fixed to the specified surfaces of the threaded rods by means of magnets, while on the control surfaces of the reference platforms, the measuring rods of pulse sensors of linear displacements of the measuring system for measuring the group drawing of studs, built on the basis of pulse counters from linear displacement sensors, a personal computer and a device data output, and the hydraulic power unit is made containing a hydraulic cylinder with a upsetting piston, by means of which the pistons of the hydraulic power unit are returned to their original position.

The specified technical result is also implemented in the form of UGVSH flange connections, containing a support mechanism with a hydraulic power mechanism installed on it, threaded rods for screwing onto studs, wrenches for tightening castellated nuts, while the hydraulic power mechanism contains hydraulic power units, each of which is made in the form multi-stage hydraulic cylinders with pistons, wherein said pistons are made with internal holes for interaction with threaded rods, and the ends of the hydraulic cylinders are made sequentially leaning one into the other, and the device is equipped with hydraulic cylinders with a upsetting piston, made with the possibility of returning the pistons of the hydraulic power unit to its original position, when in this case, each hydraulic cylinder with a upsetting piston is mounted jointly and coaxially with the upper hydraulic cylinder of the hydraulic power unit, while the hydraulic power mechanism containing hydraulic power units, each of which is made in the form of a multi-stage scalloped hydraulic cylinders with pistons and a hydraulic cylinder with a upsetting piston are mounted together in one unit.

In a particular case, the wrench for turning the castle nuts is made with a technological opening in the side wall with a width that ensures the installation of a reference platform, an impulse sensor and the turning of the castle nut.

The control of the absolute elongation of the amount of drawing of the studs is carried out from the control surfaces of the reference platforms, while the threaded rods are twisted all the way into the ends of the studs, and the control surfaces of each reference platform are manually aligned with an emphasis on the outer cylindrical and base surfaces of each threaded rod, horizontally in the same plane with the end ones. surfaces of the studs and fix the reference pads on the magnets.

The horizontal alignment in one plane of the end surfaces of the studs and the control surfaces of the reference platforms does not contradict the hypothesis of flat sections during tension of the rods, since the application of an external force (from the hydraulic power unit) to a distance greater than the diameter of the rod (the diameter of the threaded rod), the stresses are distributed almost evenly over the section, and the sections themselves remain flat even after deformation (I.A. Birger et al. “Strength calculation machine parts”, Mashinostroenie, Moscow, 1966, p.7).

The alignment of the plane of the end surface of the stud with the control surface of the reference platform is carried out due to the base height of the reference platform, which is calculated as follows: (Figure 4)

N _b.r.g. = N _b.r.p. + N _b.c.t. , where

N _b.r.g. – basic height of the threaded socket of the threaded rod;

N _b.r.p - base height of the reference platform;

N _b.c.t. is the base height of the surface of the cylindrical end.

The specified alignment of the plane of the end surface of the stud with the control surface of the reference platform makes it possible to increase the accuracy of measuring the absolute elongations of the stud elongation value, since in the proposed measuring scheme, there is no composite rod longer than 1.5 m, based on one side in the core of the pin and the other - the spring part of the rod, which is in contact with the displacement sensor IC.

In the proposed invention, the digital measuring system consists of pulse linear displacement sensors (installed with an interference fit on the reference platform at each threaded rod), pulse counters from linear displacement sensors, a personal computer and a data output device. This system has the following advantages compared to known similar measuring systems:

- setting the zero point of the sensors is carried out from the control post removed from the working area;

- simultaneous display of readings of all sensors on one monitor, which is outside the working area;

- a fully digital system that eliminates the introduction of additional errors in signal transmission and digitization, because readings are transmitted in digital form all the way from the sensors to the indication and registration device (computer);

- registration of sensor readings with the possibility of further processing with the help of external programs, thus, it is possible to build graphs and tables, create reports;

- automated control of the output of the measured values beyond the limits of the permissible range.

In the proposed invention, the return of the pistons of the hydraulic power mechanism is carried out in each power unit using a hydraulic cylinder with a draft piston. For well-known UGVSH in power units, taking into account the tightness on the flange connection, up to 6 hydraulic cylinders can be arranged in one power unit, so the force of returning their pistons to their original position can reach 1.2 tf. With such an effort, the spring shock absorber turns out to be overall and does not meet the requirements of tightness, and the layout of the hydraulic cylinder with the upset piston in one power unit becomes expedient.

In the proposed invention, the control of the absolute elongations of the amount of drawing of the studs is carried out using reference platforms, which are installed in the area of the threaded connection of the stud with a threaded rod. On the control surface of each reference platform, measuring rods of pulse linear displacement sensors connected to the measuring system are installed with the necessary tightness.

Each reference platform is installed manually with an emphasis on the outer cylindrical and base surfaces of each threaded rod, fixed on magnets, and the housings of pulse linear displacement sensors are mounted on brackets that are fixed on a fixed support mechanism. This design of the stud elongation measuring device simplifies the circuit and improves the accuracy of measuring the absolute elongations of the studs due to the absence of a composite spring-loaded rod. The manufacture of threaded rods becomes more technologically advanced, since there is no need for a central hole for deep drilling (up to 1.5 m). Setting the zero point of the sensors is carried out from the control panel removed from the radiation-hazardous zone. Simultaneous display of readings of all sensors on one monitor is carried out on the control panel in the radiation-safe zone.

The design of the wrench for tightening castle nuts has a technological opening in the side wall, which ensures quick and accurate installation of the reference platform, an impulse sensor and tightening the castle nut in cramped conditions.

The implementation of the present invention will allow to obtain a technical result in the form of increasing the accuracy of simultaneous measurements of the absolute elongations of the group drawing of the studs of flange joints at high crowding, improving the manufacturability of the UGVSH design, reducing the number of maintenance personnel and the absorbed dose of gamma and beta radiation during repair work and recharging the reactor, as well as replacement of PG.

The essence of the invention is illustrated by the following graphic figures:

Fig. 1 - Fragment of the general view of the UGVSH.

Fig. 2 - Section A-A. The location of the hydraulic power unit mounted on the stud.

Fig. 3 - View B. The location of the cylinder with the piston of the draft return of the pistons of the hydraulic power mechanism in one unit.

Fig. 4 - View B. Location of the pulse linear displacement sensor and the reference platform on the outer cylindrical surface of the threaded rod in the area of the threaded connection of the stud and rod with an emphasis on the cylindrical and base surfaces.

Fig. 5 - View D. Mounting the bracket on a fixed support mechanism.

Fig. 6 - View D. Fastening of an impulse sensor of linear displacements on a bracket.

Fig. 7 - Section E-E. Installation of the reference platform on the outer cylindrical surface of the threaded rod and the location of the wrench for tightening the castellated nuts.

Fig. 8 - Wrench for tightening nuts.

Fig. 9 - Scheme of the electrical structural measuring system.

The proposed method of group drawing of studs of flanged connections of reactors or steam generators is carried out as follows.

A cover 1 is installed on the reactor vessel or steam generator (Fig. 2), and through the mounting holes 2, the studs 3 are screwed to a certain depth into the reactor vessel, and spherical washers 5 are installed on the mounting thread 4 of the stud 3 and castellated nuts 6 are screwed on with a certain torque. Then the threaded rods 7 are screwed onto the technological thread 8 (Fig. 4) until they stop at the end 9 of the stud 3, and keys 10 are installed on the slotted nuts 6 through the threaded rods 7. The support mechanism 11 ( Figure 1) with a hydraulic power mechanism 12 installed on it. A spherical washer 14 is put on the thread 13 of the threaded rod 7 (Figure 3) and the thrust nut 15 is screwed on with a certain torque. Each reference platform 16 (Figure 2.4) is installed manually until it stops on the base platform 17 and the cylindrical surface 18 of the threaded rod 7 attached to the surfaces with magnets 19. On the control surfaces 20 of the reference platforms 16, measuring rods 21 of pulse sensors are installed with the necessary tightness linear displacements 22, which are part of the measuring system of the group drawing of the studs (Fig.9), built on the basis of pulse counters 23 from the sensors 22, a personal computer 24 and a data output device 25, located in the monitoring and control station 26. All readings of the sensors 22 are set to the zero reference point for measuring the absolute elongation of all studs simultaneously at the control and management station 26.

From the hydraulic station (not shown in Fig. 1) through the pipelines, in accordance with the technological process and the design documentation, the working fluid is supplied to each hydraulic power mechanism and the group drawing of the studs 3 is performed.

Personal computer 24, using special software, reads data from the RS-232 port and simultaneously displays the readings of all linear displacement sensors from studs 3 on the monitor screen 27. Input devices 25 and a printer 28 are connected to computer 24, which allows printing measurement results the absolute value of the drawing of the studs 3.

The values of the absolute elongations of the group drawing of the studs 3, which have reached the design value, are fixed, the pressure of each hydraulic power unit 29 is pressed, the castellated nuts 6 are tightened with a certain torque, the pressure is released, and the return of the pistons of the hydraulic power unit 29 is carried out in each power unit using the upset piston 30 (Fig.2,3). UGVSH is dismantled from the surface of cover 1.

A device for implementing the method of group drawing of flanged studs (UGVSH) contains a support mechanism 11 with a hydraulic power mechanism 12 installed on it, interacting with threaded rods 7 screwed on studs 3, a hydraulic power unit 29 made in the form of multi-stage cylinders 31 assembled in one unit, with keys for tightening castle nuts 10. Threaded rods 7 are installed through the internal holes of the pistons of hydraulic cylinders 30 and 31, and the ends of hydraulic cylinders 30 and 31 sequentially abut against one another. The return of the pistons of the hydraulic cylinder 31 (Figure 3) of the hydraulic power unit 29 to its original state is carried out by the upset piston 30 before the group drawing of the pins 3 (Figure 3). The piston upset of the hydraulic cylinder 30 is mounted together and coaxially with the upper hydraulic cylinder 31 of the hydraulic power unit 29 in one unit.

The control of the absolute value of the drawing of the pins 3 is carried out using reference platforms 16 (Figure 4), which are installed on the outer cylindrical planes in the area of the threaded connection of the pin 3 and the threaded rod 7 with emphasis on the base platform 17 and the cylindrical surface 18 (Figure 7).

On the control surface 20 of each reference platform 16 is installed with the necessary tightness measuring rods of pulse linear displacement sensors 22 (Figure 4). The housings of these pulse sensors 22 are fixed on brackets 32, which are mounted on a fixed support mechanism 11 (Fig.4, 5, 6). The design of the bracket 32 allows you to adjust the pulse linear displacement sensors 22 with measuring rods in height and angle of rotation relative to the control surface 20 of the reference platform 16 (Fig.5, 6).

The design of the wrench 10 for tightening the castle nuts 6 (Fig.7, 8) allows you to tighten the nuts 6 and provides the installation of the reference platform 16 with a linear pulse sensor 22 on the outer surface of the threaded rod 7.

Figure 9, as an example, shows the electrical block diagram of the measuring system, which provides, with the required accuracy, simultaneous measurements of the values of the absolute elongations of the studs in the amount of 36 pieces during the installation of the reactor flange connection using modern digital element base of components.

As a pulse linear displacement sensors 22, a thin linear displacement sensor of the LGB 542-204 series was used, and as a counter 23, which counts pulses from the sensor 22 for further conversion into a numerical form, a counter for EV-16P linear displacement sensors from Mitutoyo was used. The remaining components in this measuring system can be used from the market range of modern digital element base for wide application.

The implementation of the proposed invention will improve the accuracy of measurements of absolute elongations of the group drawing of studs with high crowding of flange joints, reduce the labor intensity of the work performed, the number of maintenance personnel and the absorbed dose of gamma and beta radiation during repair work, recharging reactors and replacing SGs.

Claims (3)

1. The method of group drawing of studs of flange connections of nuclear power plants by means of a device for group drawing of studs of flange connections, containing a support mechanism with a hydraulic power mechanism installed on it with hydraulic power units, each of which is made in the form of multistage hydraulic cylinders with pistons, threaded rods for screwing on studs, wrenches for tightening castellated nuts, which includes installing a cover with mounting holes on the reactor or steam generator vessel, screwing through the mounting holes of the cover to a certain depth into the reactor vessel the studs having a fastening thread and a technological thread, while spherical washers are installed on the fastening thread of the studs and the castle nuts are screwed with a certain torque with the keys for tightening the castle nuts, then the threaded rods are screwed onto the technological thread of the studs until it stops at the end of the studs, then onto the cover through the threaded rods and keys to tighten nuts, a support mechanism is installed with a hydraulic power mechanism installed on it, and spherical washers are put on the external thread of the threaded rods and thrust nuts are screwed with a certain torque, the absolute elongations of the stud drawing value are controlled, after which the pressure of the working fluid is applied to the hydraulic power units and group drawing of the studs is carried out, the absolute elongations of the studs are fixed and brought to the design value, after which each hydraulic power unit is pressed with the necessary pressure, the castellated nuts are tightened with a certain torque with wrenches for tightening the nuts, pressure is relieved in the hydraulic power units, after which they are dismantled device for group drawing of studs from the cover, characterized in that the control of the amount of drawing of studs is carried out by manually setting each reference platform with a control surface until it stops on the base platform and cylindrical the surface of each threaded rod with alignment horizontally in the same plane with the end surfaces of the studs and is fixed to the indicated surfaces of the threaded rods by means of magnets, while on the control surfaces of the reference platforms, the measuring rods of pulse sensors of linear displacements of the measuring system for measuring the group drawing of the studs, built on based on pulse counters from linear displacement sensors, a personal computer and a data output device, and the hydraulic power unit is made containing a hydraulic cylinder with a draft piston, through which the pistons of the hydraulic power unit are returned to their original position. 2. A device for group drawing of studs of flange connections for implementing the method according to claim 1, containing a support mechanism with a hydraulic power mechanism installed on it, threaded rods for screwing onto studs, wrenches for tightening castellated nuts, while the hydraulic power mechanism contains hydraulic power blocks, each of which is made in the form of multi-stage hydraulic cylinders with pistons, while these pistons are made with internal holes for interaction with threaded rods, and the ends of the hydraulic cylinders are made sequentially leaning one into the other, characterized in that the device is equipped with hydraulic cylinders with a upsetting piston made with the possibility of return pistons of the hydraulic power unit to the initial position, while each hydraulic cylinder with the upset piston is mounted jointly and coaxially with the upper hydraulic cylinder of the hydraulic power unit, while the hydraulic power mechanism containing the hydraulic power units, each and which is made in the form of multi-stage hydraulic cylinders with pistons, and the hydraulic cylinder with the upsetting piston are mounted together in one unit. 3. A device for group drawing of studs according to claim 2, characterized in that the wrench for turning the castle nuts is made with a technological opening in the side wall with a width that ensures the installation of a reference platform, an impulse sensor and the turning of the castle nut.

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