RU2359789C2 - Device for cutting and changing of pipes sections in pipelines - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metal deformation process and can be used for cutting and changing of pipes sections pipelines. Device contains case, fixation unit of tension bar or rope and accessory for destruction of old pipeline. Case is implemented with front stage, adapter and back stage for location on its butt end of leading end of new pipeline. Accessory for destruction of old pipeline is implemented in the form of cutter with nibbed blade, inclined into the side of device working range and installed at front stage and case adapter.

EFFECT: reliability of works increasing at trenchless replacement of destroyed sections of metallic pipelines.

5 cl, 11 dwg

Description

The present invention relates to the processing of metals by pressure and can be used for cutting and replacing sections of pipes in pipelines.

A device for cutting pipes [1], adopted for the analogue. It contains two knives kinematically connected with a reciprocating drive, having cutouts with cutting edges located at an angle to one another. The vertices of the cut-out angles of each of the knives are mutually offset relative to the axis of the device, and the cutting edges of each wedge are located at right angles to one another; while one of them is flat, and the other is inclined to the axis of the device at an angle α. During operation, the blades from the drive move towards each other, center the pipe and cut it. Then the knives return to their original position.

The advantage of the analogue is the uniform loading of the knives, an even cut line perpendicular to the axis of the pipe. The disadvantage is the impossibility of longitudinal cutting of the pipe. Also known is a device for cutting damaged sections of pipes of existing pipelines [2], also taken as an analogue. The device comprises a drive, a trolley with wheels, on which a milling cutter is connected, connected with the drive and wheels of the trolley through a mechanical transmission and a chain with rollers covering the pipe. The drive transmits torque to the cutting mechanism - the milling cutter through the central wheel of the internal gearing, the satellite and the internal gear. The device is mounted on the pipe to be cut with running wheels and secured with a chain through a shock absorber and a tension mechanism. After turning on the drive, the running wheels move the cutting mechanism. The milling cutter is brought manually using a screw mechanism and deepened until the pipe is completely cut. The drive stops and the device is moved to a new location.

The advantage of this analogue is small dimensions, rigidity of the cutter feed, an even cut layer, high cutting performance. The disadvantage is the need to dig a trench along the entire length of the replaced section of the pipeline, especially if the route passes under busy streets, buildings, railways and highways.

There is another device for replacing an underground pipeline [3], also taken as an analogue. Unlike previous analogues, the device is used for trenchless replacement of pipeline sections from brittle materials (ceramics, cast iron, asbestos cement, etc.) during the repair and reconstruction of underground utilities. This device contains a cylinder head with a socket for accommodating the front end of the new pipeline, a device for destroying the old pipeline, made in the form of a milling head and a screw mechanism, placed in the old pipeline. The front part covers the old pipeline. During rotation, the milling head destroys the old pipeline and its fragments, together with the adjacent soil, are transported by a screw into the receiving pit. As the old pipeline collapses, the tip moves forward, pulling the new pipeline into the ground.

The advantage of this device is that when trenchless replacement of the pipeline does not occur, the soil mass and groundwater are not contaminated.

Disadvantages - cumbersome, high energy intensity of crushing the old pipeline, the unreliability of transporting its fragments by a screw mechanism.

There is also known a device for replacing an underground pipeline [4], adopted as a prototype. It contains a percussion mechanism in the head with a socket for accommodating the front end of the new pipeline and a device for destroying the old pipeline, in which there is a container connected to the percussion mechanism and placed between it and the conical tip.

The advantage of this device is to increase the reliability of operation compared to peers, as well as the ability to replace the underground pipeline without digging a trench from the surface. The disadvantage is that, like analogs, the prototype must destroy a completely old pipeline of brittle materials with high resistance to destruction and movement of debris. The prototype is not capable of destroying the old steel pipeline with a viscous structure.

The objective of the present invention is to eliminate the disadvantages of analogues when using their advantages.

This task is achieved by the fact that in the device for cutting and replacing pipe sections in pipelines containing a housing, a tie rod or cable fixing unit and a device for destroying an old pipeline, it is provided that the housing is equipped with a front stage, an adapter and a rear stage for placement on its front end of the front end a new pipeline, and the device for the destruction of the old pipeline is made in the form of a cutter with a pointed blade, tilted towards the working movement of the device and mounted on the front with Upenu and the housing adapter. The outer diameter D of the old pipeline, the outer diameter D _{1 of the} rear stage, the diameter of the front end of the new pipeline D ₂ and the outer diameter D _{3 of the} front stage of the casing are related by the relation: D ₁ ≥D = D ₂ > D ₃ . The outer diameter D _{3 of the} front stage, the height H from the top of the torch to the front stage and the outer diameter D of the old pipe are connected by the ratio D ₃ + H> D. The angle of inclination α of the cutter blade is selected within the range of α = 12 ÷ 43 °, and the angle of suspension β of the cutter blade is selected within the range of β = 25 ÷ 48 °.

Thus, the proposed device is equipped with a stepped case, the back of which has an outer diameter equal to the diameter of the replaced pipe, and the front part forms a step - a ledge for the fixed mounting of the torch with a pointed blade, the top of which is located in a plane passing through the axis of the back part with an inclination of direction of movement. The rear edge of the device is connected to a new pipeline, and at the front end there is a fastening of a traction device, such as a rod or cable, drawn through the old pipeline.

The list of figures drawings.

Figure 1 shows the proposed device for cutting and replacing sections of pipes in pipelines. In Fig.2 - the same, in a longitudinal section passing through its axis. Figure 3, 4 and 5 shows the cross-section aa, bb and bb, revealing the stage of entry of the proposed device into the cavity of the old pipeline. 6, 7 and 8 show a diagram of the occurrence of a tearing force depending on the angle of inclination of the cutter blade to the axis of the device. Figure 9, 10 and 11 shows a diagram of the decomposition of the tearing force on the lateral faces of the sharp wedge of the blade 10 of the cutter 9 in section G-D (figure 2).

The device (figures 1, 2) consists of a front stage 1, an adapter 2 and a rear stage 3. At the front stage 1 there is a mounting unit for the traction device 4, for example, in the form of an earring 5 and a roller 6 inserted through a pair of side holes 7 at the beginning front stage 1.

At the end end of the rear stage 3, made in the form of a pipe with an outer diameter D ₁ equal to or slightly larger than the outer diameter of the old pipeline D (D ₁ ≥D), is fixed by any known method, for example by welding, the front end of the new pipeline 8, the outer diameter D ₂ which is equal to the diameter of the rear stage (D ₂ = D ₁ ).

The front stage 1 has an outer diameter diameter D ₃ smaller than the diameter of the rear stage (D ₃ <D ₁ ) and is connected to the latter by means of a rigid adapter 2 corresponding in size to the end of stage 1 and the beginning of stage 3.

The axis of the front stage 1 is eccentric to the axis of the stage 3 by Δ (Fig. 2). External contact lines of the surface of the front stage 1 of the adapter 2 of the rear stage 3 and the new pipeline 8 are located on the inner surface of the old pipeline. On the step ledge, formed by the difference in diameters D ₁ and D ₂ , as well as on the transition between them, on the surface of the adapter 2 is installed, for example, by welding, a cutter 9 with a pointed blade 10, inclined towards the working displacement and protruding above the surface of the step, with the condition D ₃ + H> B. Such a cutter in a shape resembling a shark fin, when moving the device inside the old pipeline, provides local ripping action along the generatrix of the old pipeline, first lifting its upper part to a certain height h (Fig. 4), then tearing it from the inside like a knife for opening metal canned goods cans (figure 5).

Changing the angle of inclination α of the blade 10 allows a wide range to change the tearing force F arising at the top of the blade along its axis of symmetry. For example, with the same force N arising on the top of the wedge-shaped blade of the torch in the direction of tension of the traction device or cable and its introduction into the wall of the old pipeline, breaking the force F (figure 2) at an angle of inclination α = 10 ° (figure 6) more than 5 times greater than the force N according to the well-known rule of the parallelogram of the balancing forces on the wedge Fα ₁ = 5.88 N (Fig.6). With an increase in the angle α, the tensile force decreases significantly. At α ₂ = 30 ° Fα ₂ = 2N (Fig. 7), and at α ₃ = 50 ° Fα ₃ = 1,3N (Fig. 8).

A significant influence on the force breaking an old pipeline is also exerted by the angle of suspension β of the wedge-shaped blade 10, on the faces of which, according to the same well-known rule of the parallelogram of balancing forces on the wedge, when the tensile force F is applied, the forces F ′ and F ″ develop on the faces of the acute-angled wedge with angle β , multiple exceeding the breaking force F (Fig.9, 10, 11).

For example, the tearing force F applied along the wedge axis is decomposed into a pair of equal balancing forces F ′ and F ″ tearing the body perpendicular to the faces of the wedge, each of which, depending on the angle of suspension β, can be significantly greater or less than F.

So, at β = 20 ° each of the breaking forces F ′ and F ″ is almost three times greater than the axial force F. F ′ _β1 = F ″ _β1 = 2.88 F (Fig. 9). At β ₂ = 40 °, these lateral tensile forces F ′ _β1 = F ″ _β2 = 1.46F (FIG. 10); and at β ₃ = 60 °, the forces F ′ _β3 = F ″ _β3 = F (Fig. 11).

With an increase in the angle of inclination α of the blade 10 above 43 °, the rupture deformations of the walls of the old pipeline begin to be replaced by collapse deformations, the implementation of which requires much greater efforts.

With an increase in the angle of suspension β of the blade 10, the lateral tensile forces F ′ and F ″ on the faces of the wedge decrease by several times, however, the strength properties and resistance of the wedge itself increase significantly.

Depending on the thickness and diameter of the pipe of the old pipeline, the angle of inclination α of the pointed blade of the torch 9 relative to the axis of the front stage, as well as the angle of suspension β of the blade 10 (Fig. 2, 6, 7, 8) of the torch 9 (Fig. 9, 10, 11) in a cross section in each case, the applications are selected experimentally.

The experiments showed that the optimal option for the angle of inclination α of the blade 10 is the interval α = 12 ÷ 43 °, and for the angle of suspension β of the blade 10 - the interval β = 25 ÷ 48 °. If necessary, the surface of the wedge-shaped blade can be reinforced with any wear-resistant coatings applied by any known method.

The device operates as follows.

Through a replaceable section of the pipeline, a traction or cable is laid and fixed on the device. When creating traction from a power drive, for example, from a tractor or a winch, the cutting device comes into contact with the end face of the old pipeline, rips up its upper wall like a can opener (Fig. 1) and simultaneously drags a new pipeline along without changing the diameter, since the resulting after the cut, the increased perimeter size of the old pipeline allows this to be done. Work continues until the entire replacement section is drilled.

Information sources

1. Copyright certificate No. 912404, cl. B23D 21/00 dated 03/15/1982

2. Copyright certificate No. 902991, cl. B23D 21/00 of 02/07/1982

3. German patent No. 362,026, class ЕВВ 7/26.

4. RF patent No. 2062941, cl. F16L 55/18 dated 06/27/1996.

Claims (5)

1. A device for cutting and replacing pipe sections in pipelines, comprising a housing, a tie rod or cable fixing unit and an apparatus for destroying an old pipeline, characterized in that the housing is made with a front stage, an adapter and a rear stage for placement of a new front end on its end end pipeline, and the device for the destruction of the old pipeline is made in the form of a cutter with a pointed blade, tilted towards the working movement of the device and installed on the front stage and the adapter mustache. 2. The device according to claim 1, characterized in that the outer diameter D of the old pipeline, the outer diameter D _{1 of the} rear stage, the diameter of the front end of the new pipeline D ₂ and the outer diameter D _{3 of the} front stage of the housing are related by the ratio:
D ₁ ≥D = D ₂ > D ₃ . 3. The device according to claim 1 or 2, characterized in that the outer diameter D _{3 of the} front stage, the height H from the top of the torch to the front stage and the outer diameter D of the old pipe are connected by the ratio:
D ₃ + H> D. 4. The device according to claim 3, characterized in that the inclination angle α of the cutter blade is selected within the range of α = 12 ÷ 43 °. 5. The device according to claim 4, characterized in that the suspension angle β of the cutter blade is selected within β = 25 ÷ 48 °.

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