RU2693564C1 - Device for internal insulation of pipeline welded joint - Google Patents

Abstract

FIELD: construction; transportation.

SUBSTANCE: invention relates to construction of pipelines and can be used for internal insulation of pipe joint with inner protective coating. Device for inner insulation of welded joint 10 of pipeline 9 comprises a power drive including cylindrical housing 1 and a coaxially arranged on it cylindrical elastic working element 2 made with the possibility of radial expansion at creation in its cavity of excess pressure. Cylindrical sealing shell 5 made from elastic anti-adhesion material is coaxially installed on the power drive on outer surface of working element 2. Device is equipped with bushings 3, 4 installed on ends of power drive and fixed on housing 1. Each bushing 3, 4 adjoins by its end to end face of shell 5 and its inner cylindrical surface – to outer surface of working element 2. In the device inoperative state, shell 5 is in a state which is compressed in the axial direction.

EFFECT: invention allows increasing working pressure in power drive up to 10 bar; improving operating reliability of power drive; to ensure guaranteed tightness at formation of annular gap cavity in zone of welded connection 10; simplifying the design and reducing the manufacturing cost of elastic actuator 2 of the power drive; reduced circuit feeding compound into cavity of annular gap in zone of weld connection 10.

8 cl, 15 dwg

Description

TECHNICAL FIELD

The invention relates to the construction of pipelines and can be used for internal insulation of a welded joint of pipes with an internal protective coating.

BACKGROUND

A device for hermetic mounting on at least one cylindrical element (FR 2736986 A1) is known. The device is intended for hermetic fastening on at least one cylindrical element and is used in the repair of pipelines. It contains the first clutch, the second clutch, which is coaxial with the first clutch and has a deformability greater than the deformability of the first clutch. The second coupling is rigidly and hermetically fastened with its two ends on the first coupling. Two cylindrical rings are coaxial with the second clutch, worn on this clutch and each of them is rigidly attached by one of its edges to one end of the second clutch. The device is equipped with means for introducing the current pressure medium between the first and second couplings. The device is introduced into the pipeline and serves under pressure the current environment between the first and second couplings. The second coupling is deformed and pressed against the inner surface of the pipeline. The loose edges of the rings are embedded in the wall of the pipeline and ensure the tightness of the connection and the mechanical strength of the mounting device in the pipeline. The device improves the reliability of the pipeline. This device has several disadvantages:

- high cost of the device;

- the device is disposable and is intended for its rigid attachment to the inner walls of the pipeline;

- after sealing, the device remains in the internal cavity of the pipeline, and the tubes supplying the current medium under ultrahigh pressure go beyond the end of the pipeline, which multiply reduces its flow area, contributes to quick clogging, eliminates the possibility of internal cleaning and complicates further installation works;

- for carrying out the sealing of the pipeline, it is necessary to use pumping equipment for 1200 ... 1600 bar and water, which makes it extremely difficult to work in the field.

A device for repairing underground pipelines (US 4861248 A) is known. The device consists of a cylindrical elastic shell, two end caps, a sleeve, a cable and tubes for supplying, mixing and feeding into the annular gap of a two-component compound. At both ends of the elastic sheath, cylindrical plugs are mounted and rigidly fixed. A tight connection is created between the inner surface of the elastic sheath and the cylindrical surfaces of the plugs. In the internal sealed cavity of the device, both plugs are connected by a cable, limiting their movement relative to each other. A compound delivery unit is mounted inside the device. In the middle part, a sleeve is mounted coaxially on the surface of the elastic sheath without the possibility of their separation. On the sleeve

One channel is mounted connecting the feed unit of the compound to the outer surface of the device. When working on the sealing of the emergency section of the pipeline, the device is positioned in the internal cavity of the pipe in the zone of its damage or joint. Then the device is supplied with compressed air. Pressure is generated in the expansion device. The elastic sheath at both edges outside the placement of the device sleeve expands and comes into contact with the inner surface of the damaged pipe / pipes with the formation of a closed annular gap. A two-component compound is fed into the formed closed annular gap through the existing channel.

This device has the following disadvantages.

1) The device has low reliability. Only the central portion of the elastic sheath has increased strength. Peripheral areas of the elastic sheath are not strengthened by anything, including the cord. When compressed air is injected into the internal cavity of the device, the peripheral sections of the elastic shell expand and abut against the internal walls of the pipeline. In this state, the pressing force of the elastic shell to the internal walls of the pipeline is close to zero. With further injection of air into the internal cavity of the device radial expansion of the elastic shell does not occur. Since there is a radial gap between the hard plugs of the device and the walls of the pipeline, as the pressure increases further, the peripheral sections of the elastic shell will be pushed through these gaps into the cavity of the pipeline. In the cavity of the pipeline, the shell will increase uncontrollably until its destruction.

2) The device cannot be used for internal insulation of the welded joint of the pipeline with the preliminary removal of air from the cavity of the annular gap. The device does not allow to achieve the required level of sealing of the annular gap of the welded joint of the pipeline, required for internal insulation with preliminary evacuation of the annular gap cavity. This is due to the lack of possibility of creating the required pressure in the internal cavity of the device due to its design flaws. To ensure the tight connection of the elastic shell with the inner surface of the pipeline in the internal cavity of the device, it is necessary to create a pressure that provides the required force of its pressing against the wall of the tube. In this case, the required force of the compression seal is determined by the roughness of the inner wall of the pipeline. For vacuum systems, there are special requirements for sealing joints. In the prior art it is known that in order to achieve vacuum tightness of a vacuum system, a compressive force on an elastic seal should be in the range of 30 to 145 N / cm ² (Plug-in Connections - Connections using sealing gaskets, http://www.pro-vacuum.ru/ sposobv-soedineniia-valdcumnvkh-sistem / razemnye-soedineniia / soedineniia-s-pomoshchiu-uplotniaiushchikh-prokladok.html). At the same time, the minimum pressure value corresponds to vacuum joints with polished sealing surfaces, and the maximum pressure corresponds to the surface with rough treatment. When sealing the ring

the gap of the welded joint of the pipeline, the compression force of the elastic seal must be chosen above the average recommended value.

3) The device does not allow filling the cavity of the annular gap of the welded joint with a compound under pressure. When the compound is injected, either the cavity of the annular gap will be filled only partially, or it will completely depressurize and the compound will begin to fill the cavity of the pipeline on both sides of the device. The device has a channel for supplying the compound to the cavity of the annular gap, but there is no channel for removing air from it. As the compound is pumped into the cavity of the annular gap, the pressure of the air there will increase. When an equilibrium state is reached between the pressure in the cavity of the annular gap and the discharge pressure of the compound, the filling of the cavity will cease. When an equilibrium state is reached between the pressure in the cavity of the annular gap and the pressure of the elastic sheath against the internal walls of the pipeline, the cavity of the annular gap completely depressurizes and the compound will begin to fill the pipeline cavity.

4) The device does not allow the pumping of air and the flow of the compound into the cavity of the annular gap through third-party channels that do not pass through the internal cavity of the device. This sharply limits the functionality of the device, its reliability and complicates the maintenance of equipment. For example, if the supply channels of a two-component compound are clogged, cleaning them requires complete disassembly of the device, including tight connections of the plugs with an elastic sheath. Frequent reassembly of the device may result in loss of tightness.

5) There is no possibility of flushing the supply hoses and tubes of the device after the end of the process of filling the annular gap with a compound.

6) The impossibility of forced withdrawal for disposal of poor-quality compound from the circuit of its supply to the cavity of the annular gap.

Closest to the proposed invention is a device that implements the method of internal insulation of the welded joint of the pipeline according to the patent RU 2667856. The method consists in the fact that a protective sleeve is arranged coaxially inside the pipes to be connected. After welding the joint of the pipes, they seal the end annular gaps between the protective sleeve and the pipes to be joined with the formation of an annular cavity between the outer surface of the sleeve and the inner surface of the welded joint and the adjacent surfaces of the connected pipes. The sealing of the end annular gaps is carried out by inserting a device inside the connected tubes for sealing the end annular gaps. The device contains a power actuator, including a cylindrical elastic working body, as well as a cylindrical shell made of elastic anti-adhesive material coaxially located on the surface of the working body. Alternatively, the device has a housing and a shell with a bed for a protective sleeve in the form of an annular recess open on one side with a lateral ring emphasis on the outer surface of the shell. In addition, channels are integrated into the casing for evacuating air and feeding the compound into the annular cavity of a sealable welded joint. The described version of the device works as follows. Before entering the device into the cavity

Pipeline on the bed sheath fit protective sleeve. Inside the working body create pressure. There is a radial expansion of the working body. The side annular abutment of the shell engages with the end of the protective sleeve, and the bed of the shell is pressed against the inner surface of the protective sleeve. After fixing the protective sleeve on the device suspend the creation of excess pressure inside the working body. A device with a sleeve mounted on it is inserted into the cavity of the pipeline, positioned relative to the weldable joint to be sealed, and then continue to create an overpressure. The protective sleeve prevents further radial expansion of the section of the working body inside its cavity. Under the influence of increasing pressure, the pressing force of the central portion of the working body to the protective sleeve increases. At the same time outside the protective sleeve, there is a radial expansion of the end sections of the working body of the device to their emphasis on the internal walls of the pipeline. On both sides of the protective sleeve, the working member presses the casing to the surfaces of the connected pipes on both sides of the protective sleeve, and thereby the end annular gaps of the annular cavity are sealed. After sealing the end annular gaps from the annular cavity the air is pumped out and its tightness is monitored. The hermetic annular cavity is filled with a compound. Polymerization of the compound is carried out. After the polymerization process is completed, the pressure inside the working member is reduced with the shell detached from the protective sleeve and the inner surfaces of the connected pipes and the sealing device is removed from the pipeline.

The device described in patent RU 2667856 has the following disadvantages:

1) The maximum allowable working pressure in the power drive of the device with a reinforced elastic working body has a limit of 2.5 bar, which is caused by its design. When using unreinforced working body, the allowable working pressure in the power drive of the device is reduced to 0.2 ... 0.8 bar. To ensure the tightness of the annular gap of the welded joint using this device, it is necessary to use a highly elastic cylindrical shell of great length. If there are defects on the inner surface of the pipe in the form of scratches, craters, ulcers, pores, inclusions, etc., at a pressure of 2.5 bar, the required tightness of the annular gap is not achieved. The ingress of foreign bodies into the contact zone of the shell with the inner surface of the pipe, such as: villi, dust particles, debris, etc., significantly increases the leakage in the cavity of the annular gap. It is possible to eliminate the effect of pipe surface defects and the presence of small foreign particles in the isolation zone to acceptable limits only by increasing the pressure. However, even a slight increase in pressure above 2.5 bar leads to an uncontrolled expansion of the elastic working body along the internal cavity of the pipeline and, consequently, to a sharp decrease in the life of the device.

2) The significant influence of multiple factors on the tightness of the annular cavity of the welded joint when sealing with pressure in the actuator within 2.5 bar necessitates the implementation of mandatory high-quality tightness control. To conduct an appropriate leak test, it is necessary to pump air out of the annular gap cavity.

to an absolute pressure of 1.0 ... 0.5 Pa and below. To create a specified vacuum in the cavity of the annular gap, special vacuum equipment is required, suitable for operation in field conditions, including at negative temperatures. The duration of the process of pumping out air and the subsequent monitoring of the tightness of the cavity of the annular gap can be from 20 to 40 minutes. Under pipeline construction conditions, this significantly hinders the conduct of all installation work.

3) Due to the danger of depressurization, there is no possibility of supplying the annular gap of the welded joint of the compound under pressure into the cavity. This significantly limits the technological capabilities of the device, does not allow to accelerate the process of filling the annular gap with the compound and slows down the degassing process, which causes the appearance of pores in the polymerized compound, which reduces the insulation quality of the welded joint.

4) To create a pressure above 1 bar in the power drive, the device should use an elastic body reinforced with cord. Reinforcement pads complicates the process of manufacturing a working body and increases its cost. Reinforced working body in length has a different ability of radial expansion. The middle part of the elastic working body has the greatest ability of radial expansion. With increasing distance from the center of the working body to its end sections, the ability for radial expansion is significantly reduced. During the injection of compressed air, the reinforced working body of a power drive, radially expanding, takes the form of an ellipsoid. When mounting the sleeve on the device during the injection of compressed air, the working body initially presses the central portion of the shell to the central portion of the protective sleeve. When the pressure rises, the area of pressing the shell to the protective sleeve increases. Upon reaching full pressure of the shell to the inner surface of the sleeve, the side stop on the bed engages with the end surface of the sleeve. The elasticity of the working body substantially depends on the ambient temperature. Therefore, the pressure in the actuator, in which the engagement of the anvil of the shell with the end surface of the protective sleeve occurs, can also fluctuate significantly, which limits the possibilities for automating the process. In this case, the installation of a protective sleeve on the device should be made with high-precision manual pressure control.

5) Since the middle part of the reinforced working body has the greatest ability of radial expansion, then the force of pressing the shell against the inner walls of the pipeline in the central section will be maximum. In this case, the smaller the length of the reinforced working body, the greater the gradient of the force pressing the shell to the walls of the pipeline along the axis of the device. To ensure an acceptable gradient of force pressing the shell along the axis, the length of the reinforced working device of the device should exceed the length of the cylindrical shell 3 ... 5 times.

6) The large length of the reinforced working body causes a significant increase in the length of the device and the length of disposable tubes through which air is pumped out and the compound is fed into the annular cavity

weld gap. This arrangement of the device is extremely negative for its performance. The use of long tubes for pumping air and supplying the compound with a large length of the working body significantly increases the likelihood of clamping these tubes between the inner surface of the pipeline and the working body under pressure.

DISCLOSURE OF INVENTION

The technical problem solved by the invention is as follows:

1) the creation of a device that allows to increase the working pressure in the power drive to at least 10 bar;

2) improve the reliability of the power drive;

3) to ensure guaranteed tightness when forming the cavity of the annular gap in the zone of the welded joint.

4) to simplify the design and reduce the cost of manufacturing an elastic working body of the power drive device.

5) to cut the contour that feeds the compound into the cavity of the annular gap in the zone of the welded joint.

The technical problem is solved by a device for internal insulation of a welded joint of a pipeline, containing a power actuator, including a cylindrical body and a cylindrical elastic working body coaxially located on it, capable of radial expansion when an overpressure is created in its cavity, and also coaxially mounted on the external actuator the surface of the working body of a cylindrical shell of elastic anti-adhesive material, which, according to the invention, is provided bushings mounted on the ends of the power drive and fixed on the housing, each sleeve adjacent its end to the end of the shell and its inner cylindrical surface - the outer surface of the working member, wherein in the inoperative state of the device sheath is in a compressed state in the axial direction.

In a preferred embodiment, the housing is made with annular recesses on the outer surface in the zones of the ends of the actuator, and the working body is made with annular projections located in these recesses, each annular protrusion made in the section of the working body located between the housing and the corresponding sleeve.

In addition, it is preferable that the housing is made open from the ends and has a channel for supplying the medium under pressure, while the channel entrance is located at the end of the housing wall, and the channel exit is located on the outer surface of the housing.

In the simplest embodiment, the shell has cylindrical outer and inner surfaces.

In another embodiment, the shell has an axisymmetric recess in the middle part of the inner side, while the middle cylindrical surface area

the recesses are connected by means of conical sections of the surface of the recesses with end cylindrical sections of the inner surface of the shell.

An embodiment is also possible, when the shell has two diametrically opposite deaf holes and two channels communicating with them, the axes of which are parallel to the axis of the housing on the outer side, the sleeve from the side of the said end section of the shell is made with a hole or groove , while in each channel a tube is installed tightly through the hole or groove of the sleeve.

In this case, the sleeve on the side of the specified end section of the shell is made with two flats, and the hole or groove is made in the wall separating each tip from the end of the shell adjacent to the sleeve.

It is also possible that the outer surface of the shell has two sections of different diameters, while these areas are conjugated by means of a section with a conical surface and a cylindrical section adjacent to it, forming a centering girdle under a protective sleeve adjacent to a section of larger diameter with the formation of a lateral ring stop ledge.

LIST OF DRAWINGS

FIG. 1 shows the proposed device in the first embodiment of the invention in the initial state inside the pipeline.

FIG. 2 - the device according to the first embodiment of the invention in working condition inside the pipeline.

FIG. 3 - the device according to the second embodiment of the invention in the initial state outside the pipeline.

FIG. 4 is an axonometric view of a fragment of the device according to the second embodiment from the side of the hermetic input.

FIG. 5 shows a device according to the second embodiment of the invention with a protective sleeve mounted thereon outside the pipeline.

FIG. 6 — location A in FIG. 5 with centering girdle on an enlarged scale.

FIG. 7 is a fragment with a centering collar on an enlarged scale in axial section perpendicular to the section in FIG. 6

FIG. 8 shows a device according to the second embodiment of the invention with a protective sleeve fixed thereon outside the pipeline.

FIG. 9 - the device according to the second embodiment of the invention inside the pipeline in a position ready for the formation of an annular gap in the zone of the welded joint.

FIG. 10 - the device according to the second embodiment of the invention inside the pipeline in a position ready to fill the annular gap with a compound.

FIG. 11 is a cross-section along BB in FIG. 9

FIG. 12 is a section along BB in FIG. ten

FIG. 13 - place G in FIG. 12 on an enlarged scale.

FIG. 14 is an axonometric view of a fragment of the device according to the second embodiment of the invention in a position ready to fill the annular gap with a compound (pipeline not shown).

FIG. 15 shows a device according to the second embodiment of the invention, after isolating the welded joint in a position ready for its removal from the pipeline.

EXAMPLES OF THE PREFERRED IMPLEMENTATION OF THE INVENTION

FIG. 1 shows a diagram of the first embodiment of the proposed device for internal insulation of a welded joint of a pipeline. The device contains a power drive, which includes a housing 1 and a cylindrical elastic working body 2 mounted coaxially mounted on it.

At the ends of the actuator mounted bushings 3 and 4, which are fixed on the housing 1 from axial displacement. Each sleeve 3, 4 is adjacent with its end to the end of the shell 5 and its inner cylindrical surface to the outer surface of the working body 2.

At the same time on the outer surface of the housing 1 of the power actuator on both its end sections made annular recesses - grooves 6, and on the inner surface of the elastic working body 2 with both its ends formed annular projections - sealing belts 7, corresponding to the grooves 6 on the housing 1 in shape, size and location. Sealing belt 7 of the working body 2 is placed in the annular grooves 6 of the housing 1 and crimped sliding sleeves 3, 4, mounted on the outer surface of the working body 2. The sleeves 3 and 4 are rigidly fixed on the housing 1 from axial displacement. In the housing 1, a channel 8 is formed. On the one hand, the channel 8 extends to the end of the housing 1, and on the other hand, to its outer surface in the abutment zone its outer surface is mounted a cylindrical shell 5 of elastic, vacuum-tight, anti-adhesive material, for example, from silicone. The length of the shell 5 to its installation exceeds the distance between the ends of the sleeves 3, 4 2 ... 10%. The shell 5 is mounted in a pre-compressed state, and its ends are pressed tightly to the ends of both sleeves 3 and 4. In this case, the working body 2 is enclosed in a closed cavity formed between the outer surface of the housing 1, the inner ends of two sleeves 3, 4 and the inner surface of the cylindrical shell 5.

In its simplest form, the sealing sheath 5 is an elastic vacuum tight sleeve with cylindrical outer and inner surfaces. The device in the initial state is located inside the pipeline 9 in the center of the welded joint 10. The device has centering wheels on a special

controlled suspension (not shown). In the pipeline 9, in the immediate vicinity of the welded joint 10, two technological openings I and 12 are made. A steel protective sleeve 13 is located between the device and the walls of the pipeline 9. There is a radial annular gap 14 between the outer cylindrical surfaces of the sleeves 3, 4 and the inner walls of the pipeline 9 .

FIG. 2 shows the proposed device in working condition inside the pipeline according to the first embodiment of the invention.

The principle of operation of the device is based on creating pressure in it with radial expansion of the working body 2 and elastic shell 5 located on its surface, hermetically sealing off the end annular gaps between the ends of the protective sleeve 13 and the inner walls of the pipeline 9, as well as subsequent removal of air from the sealed annular gap 15 formed between the protective sleeve 13 and the inner surface of the pipe 9, filling the annular gap 15 with a compound and polymerizing it. The quality of the insulation of the cavity of the annular gap 15 in the zone of the welded joint 10 mainly depends on the quality of sealing of the end gaps between the ends of the protective sleeve 13 and the inner walls of the pipeline 9. To achieve guaranteed sealing of the end ring gaps between the ends of the protective sleeve 13 and the walls of the pipeline 9, it is necessary to create increased pressure on the inner surface of the shell 5 and thereby ensure a more dense its pressure against the walls of the pipeline 9.

Rubber is incompressible. Therefore, the volume of the elastic shell 5 with its radial expansion remains unchanged. The radial expansion of the shell 5 is accompanied by a decrease in its thickness and a reduction in length. Nothing prevents a decrease in the thickness of the shell 5; therefore, as the radial expansion progresses, the thinning of the shell 5 occurs more intensively. The friction force between its inner surface and the outer surface of the working body 2 also reduces the length of the shell 5. Moreover, with increasing radial expansion, the friction force increases and thus has a greater opposition to reducing the length of the shell 5. Moreover, due to the preliminary longitudinal compression of the elastic shell 5 in the initial state with its radial expansion of the actual reduction in length does not occur. The reduction in the length of the shell 5 is fully compensated by its elastic longitudinal expansion. This prevents gaps between the ends of the shell 5 and the ends of the sleeves 3, 4. To guarantee the prevention of uncontrolled expansion of the elastic working body 2, it is necessary that with maximum radial expansion inside the pipeline, the ends of the shell 5 completely overlap the annular radial gap 14. This is achieved provided that the end area shell 5 in its initial state exceeds or is at least equal to the cross-sectional area of the annular radial gap 14. If this condition is met, the floor st formed between the outer surface of the housing 1, the ends of the bushings 3 and 4 and the inner surface of the shell 5 will remain permanently closed in any working pressure in the working chamber of the actuator of the device. Accordingly, the working body 2 will always be inside a closed volume, and thus its uncontrolled expansion will be excluded.

The proposed device works as follows. After positioning the device in the cavity of the pipeline 9, compressed air is supplied to the channel 8. Under the pressure of compressed air, the elastic working body 2 begins to expand radially. Between the inner surface of the working body 2 and the outer surface of the housing 1 forms the working cavity of the power actuator. Under the influence of pressure transmitted from the working body 2, the shell 5 is radially expanding along its entire length. With further increase in pressure in the working cavity of the actuator, the shell 5, expanding, rests with its outer surface on the inner surface of the protective sleeve 13. Further radial expansion of the working body 2 and the shell 5 in the zone of its contact with the protective sleeve 13 stops. The working body 2 and the shell 5 continue to expand beyond the limits of finding the protective sleeve 13 on both its sides. The shell 5 reaches the inner wall of the pipeline 9, abuts against it and stops. The working body 2, resting against the fixed shell 5, also stops. Since the working body 2 is enclosed in a closed cavity, and the pressure forces are directed exclusively perpendicular to the surface on which this pressure acts, only forces directed perpendicularly to the inner surface of the pipeline 9 act on the shell 5 at its end sections . A further increase in pressure in the working cavity of the actuator increases the pressing force of the casing 5 to the walls of the pipeline 9 and increases the tightness of the annular gap 15. When the pressure in the working cavity of the force actuator reaches 10.0 bar, the injection of compressed air was stopped. While the working body 2 remains in a closed cavity. Through the technological hole 11 from the cavity of the annular gap 15 is pumped out the air to an absolute pressure of 1 mbar. Pump down time 15 sec. In the technological hole 12 serves the compound under pressure of 6 bar. The time of filling the annular gap with compound was 4 seconds. Seal the technological holes 11 and 12. On the isolated section of the pipeline put on a tape heater with a thermostat, and at a temperature of 23 degrees Celsius stand for 20 minutes. The device is removed from the cavity of the pipeline 9. Remove the tape heater. Welded joint 10 insulated.

FIG. W is a diagram of the second embodiment of the proposed device for internal insulation of a welded joint of a pipeline. The device contains a power drive, which includes a housing 1 and a cylindrical elastic working body 2 mounted coaxially on it. At the same time, on the outer surface of the housing 1 on both its end sections there are made annular recesses - grooves 6, and on both of them the ends are formed annular protrusions - sealing belt 7, corresponding to the grooves 6 on the housing 1 in shape, size and location. Sealing belt 7 of the working body 2 is placed in the annular grooves 6 of the housing 1 and crimped sliding sleeves 3 and 4, mounted on the outer surface of the working body 2. The sleeves 3 and 4 are rigidly fixed on the housing 1 from axial displacement. The design of the proposed device is illustrated by the image shown in FIG. 4. On the sleeve 4 (figure 3 and 4) made two flats 16, located diametrically opposite, and two slotted holes or groove 17, made in the wall that separates each tip 16 from adjacent to the sleeve 4 the end of the shell 5.

In the housing 1, a channel 8 is made. On the one hand, the channel 8 faces the end of the body 1, and on the other hand, on its outer surface in the abutment zone of the inner surface of the working body 2 to the outer surface of the housing 1. Between the sleeves 3 and 4 a) coaxial to the working body on its outer surface is mounted a shell 5, which has, on its one end portion from the outer side, two blind holes 18 located diametrically opposite to each other and two channels connected with them with tubes located in them 19, whose axes are located ozheny parallel to the axis of the housing 1. The hermetically installed in each channel tube 19 forming a sealed entry, introduced during assembly into the hole or slot 17 of the sleeve 4 (fig.Z, 4).

The sealing shell 5 is made of elastic, vacuum-tight, anti-adhesive material, for example, of silicone. The length of the shell 5 should be at least equal to the distance between the inner ends of the sleeves 3 and 4, but not exceed it by more than 10%.

The outer surface of the shell 5 has two sections of different diameter. These areas are connected by means of a section 20 with a conical surface and a cylindrical section adjacent to it, forming a centering collar 21 under a protective sleeve 13 (Figures 3, 4, 5, 6, 7). The centering belt 21 is adjacent to the area of the outer surface of the shell 5 of larger diameter with the formation of a lateral ring stop 23 in the form of a ledge (Fig.7). The width of the centering girdle 21, as a rule, is selected in the range from 1 to 25 mm. With a very small width of the belt 21 (less than 1 ... 2 mm), the process of centering the protective sleeve 13 on the outer surface of the shell 5 when it is mounted on the device before entering the pipe 9 becomes difficult. However, as the width of the centering belt 21 increases, the area increases contact of the shell 5 with the inner surface of the protective sleeve 13, and, accordingly, increases the friction force between them. With increasing width of the centering belt over 20 ... 25 mm significantly increases the complexity of mounting the protective sleeve 13 on the shell 5 and significantly complicates the process of removing the device from the cavity of the pipeline 9 at the final stage of the internal insulation of the welded joint 10. The diameter of the centering belt 21 is equal to the internal diameter protective sleeve 13. The area of the outer surface of the shell 5, located between the centering strap 21 and the adjacent section 22 of this surface with a smaller diameter, has a transition in de section 20 with a conical surface. Centering belt 21 closely adjacent to the blind holes 18. The ring stop 23 on the outer surface of the shell 5 is located in a plane perpendicular to the axis of the shell 5 and passing through the borders of the centering belt 21 adjacent to the blind holes 18. The height of the ring stop 23 on the shell 5 is equal to the wall thickness the protective sleeve 13, and the diameter of the adjacent section 24 of the shell 5, located between the centering belt 21 and the sleeve 4, is equal to the outer diameter of the protective sleeve 13. The diameter of the section 22 of the shell 5 located between the section 20 with a conical surface and a sleeve 3, less than the internal diameter of the protective sleeve 13.

An axially symmetric recess 25 is formed on the inner side of the cylindrical shell 5 in its middle part by means of conical sections 26 of the surface of the recess 25 with end cylindrical sections of the inner surface of the shell 5. The total length of the recess 25 is commensurate with the length of the protective sleeve 13. Depth The recesses 25 are selected such that the thinned part of the wall of the shell 5 has a compliance that is at least 30% higher than the compliance of its end sections.

The preparation of the device for its introduction into the cavity of the pipeline 9 is illustrated by the images shown in FIG. 5-8. Over the shell 5 (FIG. 5), a protective sleeve 13 is inserted into the coaxial device on the side of the sleeve 3 and slides over the centering band 21 (FIGS. 6 and 7) to the ring stop 23. Between the cylindrical section 22, the outer surface of the shell 5 (FIG. 5 ) and the inner surface of the protective sleeve 13 is retained technological gap 27. Then through the channel 8 (Fig.8) into the gap between the outer surface of the housing 1 and the inner surface of the working body 2 is supplied compressed air. The working body 2 under the influence of pressure of compressed air initially expands in its middle part, and tightly pressed against the inner surface of the shell 5 (Fig.8), repeating the inner contour of the recess 25. At the same time, the air from the cavity of the recess 25 comes out through the micro-gaps between the shell 5, the working body 2 and the sleeves 3, 4. Since the pressure forces are always directed perpendicular to the surface, when the compressed air is injected into the working cavity of the device, inside the recess 25, radial and axial components of the pressure force appear. With increasing pressure in the working cavity of the device up to 0.5 bar, the working body 2 expands radially and presses the middle, thinned area of the shell 5 to the inner surface of the protective sleeve 13. At the same time, the end sections of the shell 5, which are outside the protective sleeve 13 and have a much lower compliance do not radially expand. The radial expansion of the middle section of the shell 5 ensures the fixing of the protective sleeve 13 (Fig. 8) on the surface of the shell 5. When the pressure rises above 0.5 bar, the radial expansion of the shell 5 begins at the edges of the recess 25. When the pressure reaches 1.0 bar, the injection of compressed air stops. At the same time, sections of the shell 5 with conical sections 26 of the surface of the recess 25 are partially pressed against the inner surface of the protective sleeve 13. Due to axial components of the pressure forces from pressure on the conical sections 26 inside the recess 25, the ends of the shell 5 are pressed against the ends of the sleeves 3 and 4 With increasing pressure inside the working cavity of the device, the pressing forces of the ends of the casing 5 to the ends of the sleeves 3 and 4 also increase. At the same time, outside the protective sleeve 13, the dimensions of the casing 5 and, accordingly, the device remained zmennymi.

The ability of the proposed device to fix the protective sleeve 13 without changing its dimensions in a wide range of pressure values generated in its working cavity makes the process of fixing the protective sleeve 13 insensitive to changes in the properties of rubber, for example, with large fluctuations in ambient temperature. This greatly simplifies the process of preparing the device for its introduction into the cavity of the pipeline 9 and allows you to easily automate the process of fixing the protective sleeve 13 on the shell 5.

The device is inserted into the cavity of the pipeline 9 (FIG. 9) and is positioned so that the center of the protective sleeve 13 is located opposite the welded joint 10. At the same time, an annular gap 14 is formed on the side of the sleeve 3. The end section of the shell 5, adjacent to the sleeve 3, radial expansion must ensure the overlap of the gap 14. On the side of the sealed bushings - tubes 19 between the outer cylindrical surface of the shell 5 and the inner wall of the pipeline 9, an annular gap 28 is formed equal to the gap between the protective sleeve 13 and ducts of pipe 9. Channel 8 in the working cavity of the device resumes the supply of compressed air. With increasing pressure begins the radial expansion of the end sections of the working body 2, which causes radial expansion of the corresponding sections of the shell 5 and the radial displacement of its ends towards the inner surface of the pipeline 9. The end surfaces of the sleeves 3 and 4 partially come out of contact with the end surfaces of the shell 5. , the working body 2 of the power drive is stretched along the length, and both its end sections are displaced from the center towards the sealing belts 7 fixed in the grooves 6 on the body 1 and are pressed I to the opening ends of the sleeves 3 and 4. With axial displacement, the edge areas of the working body 2 carry along the end sections of the sheath 5 pressed against them, which causes a noticeable increase in the degree of pressing of the ends of the sheath to the ends of the sleeves 3 and 4. In the process of increasing pressure in the working cavity the devices increase the axial components of the pressure force and, accordingly, the pressure of the ends of the casing 5 is increased to the ends of the sleeves 3 and 4. When the pressure reaches 1.5 bar in the working cavity of the device, the end sections of the casing 5 (figure 10) are pressed against the inner pipeline walls 9. A further increase in pressure in the working cavity of the device occurs without radial expansion of the working body 2 and the shell 5. The shell 5 completely covers the end gaps 14 and 28. At the same time, the working body 2 is stationary inside the closed cavity until the pressure drops in the actuator of the device at the final stage of the process of internal insulation of the welded joint of the pipeline 9.

It should be noted that the minimum allowable thickness 29 of the end portion of the shell 5, adjacent to the sleeve 3, is determined from the condition of equality of the cross-sectional areas of the annular gap 14 and the cross-section of the end portion of the shell 5 in the initial position. If this condition is met, the guaranteed complete overlap of the annular gap 14 by the shell 5 and the pushing of the working body 2 through it becomes impossible.

On the side of the location of the sealed inlets in the sleeve 4 (Figures 9, 10, And, 12, 13 and 14) there are split openings 17. When pressurizing and releasing pressure in the power drive of the device, the split openings 17 provide the possibility of free radial expansion and contraction of the end section of the shell 5 on the placement side of the hermetic inlets - tubes 19 integrated therein. In this case, the split openings 17 (FIGS. 11, 12, 13) exclude the possibility of the shell 5 with hermetic inlets rotating - the tubes 19 relative to the axis of the device and thereby provide ontroliruemoe sealed position inputs - the tubes 19 relative to the horizon, which is extremely important for the vacuum impregnation of the annular gap 15 the weld joint 10 (Figure 10). In the initial state (Fig.9 and 11) the shell 5 with its end

surface is pressed to the inner side surface of the sleeve 4 and completely covers the split hole 17. At the same time, the hermetic inlets — tubes 19 (FIG. 11) occupy their extreme initial position at the minimum distance from the device axis. When pressure is pumped up in the power drive of the device, radial expansion of the end sections of the casing 5 occurs. When the casing 5 expands in the area adjacent to the bushing 4, the integrated hermetic inlets — tubes 19 — are radially displaced to their working position, corresponding to pressing the outer cylindrical surface of the end section of the casing 5 to the inner surface of the pipeline 9 (figure 10, 12, 13). One of the most important design parameters of the device is the minimum thickness of the layer 30 (FIG. 9) of the shell 5, separating its inner cylindrical surface with the outer cylindrical surface of the integrated sealed lead-in tube 19. The thickness of the layer 30 determines the maximum allowable radial displacement of the tubes 19 relative to their original position. To exclude the likelihood of pushing the working body 2 through the cutting holes 17 in the sleeve 4, it is necessary that the end of the shell 5 with integrated hermetic inlets — the tubes 19 in all their extreme and intermediate positions completely block the cutting holes 17 (FIGS. 9, 10). To ensure guaranteed overlapping of the split holes 17, it is necessary that the annular gap 28 (FIG. 9) does not exceed the thickness of the layer 30, taking into account the decrease in the thickness of the shell 5 during its radial expansion.

In the working cavity of the power drive of the device, the pressure is raised to 10 bar and fixed. From the cavity of the annular gap 15 (FIG. 10) of the welded joint through the upper hermetic inlet - the tube 19, air is pumped out to 1 mbar of absolute pressure. Then, through the bottom sealed lead-in tube 19, the compound was fed into the cavity of the annular gap 15 in the zone of the welded joint 10 under an excess pressure of 6 bar. After filling the cavity of the annular gap 15 with the compound in the zone of the welded joint 10, the channels of both tubes 19 are closed. The compound is polymerized at 23 ° C for 15 minutes. Around the welded joint 7 with adjacent sections in the internal cavity of the pipeline 9, a protective sheath 31 (FIG. 15) of the compound is formed and polymerized. Welded joint 10 insulated. Pressure is released from the working cavity of the device. The working body 2 and the shell 5 take their original position. The shell 5, due to the increased thickness of its end sections and high elasticity, is easily separated from the ends of the polymerized protective sheath 31. The technological gaps 14, 27 and 28 (Fig. 15) take their original values. The device is removed from the cavity of the pipeline 9. The welded joint 10 is insulated.

The invention allows to obtain the following technical results.

Due to the repeated increase in pressure in the working cavity of the power drive, a guaranteed vacuum tightness of the annular gap in the welded joint zone has been achieved, which eliminates the likelihood of air leaks and rejection during its internal insulation.

Increasing the pressure in the working cavity of the device eliminated the high-quality control of the tightness of the cavity of the annular gap in the welded zone.

pipeline connections in favor of express control, produced in the process of pumping air. The requirements for the vacuum depth in the cavity of the annular gap are reduced by three orders of magnitude to 500 ... 1000 Pa absolute pressure. This ensured a reduction in the duration of the process of pumping out air from the cavity of the annular gap to 30 ... 45 seconds. Significantly reduced requirements for vacuum equipment.

Increasing the pressure in the working cavity of the device made it possible to supply the annular gap to the cavity under pressure, which significantly improved the quality of the insulation of the welded joint and reduced the filling time of the annular gap cavity in the welded joint zone 5 ... 6 times.

The process of mounting and fixing the protective sleeve on the device has been greatly simplified and accelerated. It is possible to easily automate the process of fixing the protective sleeve on the device.

2.0 ... 4.0 times reduced the length of the power drive device for sealing the annular gap in the zone of the welded joint.

The probability of pressing the tubes connected to the hermetic inlets of the device for pumping out air and supplying the compound to the cavity of the annular gap in the welded joint zone is excluded.

The length of the tubes connected to the hermetic inlets of the device is shortened for evacuating air and feeding the compound into the cavity of the annular gap.

Due to the refusal of reinforcement with cords, the design and cost of manufacturing the elastic actuator of the actuator are significantly simplified.

Claims (8)

1. Device for internal insulation of a welded joint of a pipeline, containing a power actuator, including a cylindrical body and a cylindrical elastic working body coaxially located on it, made with the possibility of radial expansion when creating an overpressure in its cavity, as well as coaxially mounted on the power actuator on the outer surface the working body of the cylindrical shell of the elastic anti-adhesive material, characterized in that it is provided with bushings mounted on the ends power drive and fixed on the body, each sleeve adjacent its end to the end of the shell and its internal cylindrical surface to the outer surface of the working body, while in the idle state of the device, the shell is compressed in the axial direction. 2. The device according to p. 1, characterized in that the casing is made with annular recesses on the outer surface in the zones of the ends of the actuator, and the working body is made with annular projections located in these recesses, each annular protrusion made in the area of the working body located between the housing and the corresponding sleeve. 3. The device according to claim 1, characterized in that the housing is made open from the ends and has a channel for supplying the medium under pressure, with the channel inlet located at the end of the housing wall and the channel outlet located on the outer surface of the housing. 4. The device according to p. 1, characterized in that the shell has a cylindrical outer and inner surface. 5. The device according to p. 1, characterized in that the shell has an axisymmetric recess in the middle part of the inner side, while the middle cylindrical section of the surface of the recess is connected by means of conical sections of the surface of the recess with end cylindrical sections of the inner surface of the shell. 6. The device according to p. 1, characterized in that the shell has on its one end portion from the outside two deaf openings diametrically opposed to each other and two channels connected with them, the axes of which are parallel to the axis of the housing, the sleeve from the specified end portion the shell is made with a hole or a groove, while in each channel a tube is inserted tightly through the hole or groove of the sleeve. 7. The device according to p. 6, characterized in that the sleeve on the side of the specified end section of the shell is made with two faces and said hole or groove is made in the wall separating each face from the end of the shell adjacent to the sleeve. 8. The device according to claim 1, characterized in that the outer surface of the shell has two sections of different diameters, and these sections are connected by means of a section with a conical surface and a cylindrical section adjacent to it, forming a centering band under a protective sleeve adjacent to a section of larger diameter with the formation of a side ring stop in the form of a ledge.

Images