RU66248U1 - BLAST PIPE CUTTER - Google Patents

Abstract

The proposed device relates to special explosive devices for cutting outside pipes of oil and gas pipelines, and can find application for repair and emergency recovery work on existing pipelines.

The disadvantages of explosive technologies using the above-mentioned cumulative annular pipe cutters are that the TRKKN data cannot be used during separation operations for dismantling, emergency recovery work, on trunk pipelines having a cross section deviating from the circumference, has an insufficiently reliable initiation system, due to the need to place the initiation system in places of thickening of the shell of the charge. In addition, it is difficult to fix the TRKKN at the focal length through the use of supports, especially at low temperatures.

The technology for manufacturing TrKKN charges, based on the drawing method, is not only low-productivity, but also leads to the appearance of a number of defects that reduce the quality characteristics of UKZ. which significantly reduces the effectiveness of the products.

The technical result of the proposed utility model is the creation of a technologically advanced and economical pipe cutter for emergency recovery work on trunk pipelines

The specified technical result is achieved by the fact that the profiled metal shell with a cumulative recess angle of 87 ... 90 ° is rolled, each half-ring has an inflection, the length of which is 2 ... 3 times the width of the UKZ cross section, and the ratio of the charge cross section to its width is in the range of 0.74 ... 0.8, and the ratio of the cladding thickness to the size of the explosive layer is 0.21 ... 0.25, and the detonator for initiation is placed on the bent ends of the UKZ, at the top of the cumulative cladding, strictly along the axis charge.

Description

The proposed device contains annular cumulative charges relates to special explosive devices for cutting outside the pipes of oil and gas pipelines, and may find application for repair and emergency recovery work on existing pipelines.

In domestic practice, such situations arise during repair, emergency restoration work or the dismantling of main oil pipelines, including in the presence of residues of oil products.

Flexible cord-shaped cumulative charges (ShKZ) based on an elastic explosive were used as an analogue [Cumulative cord-shaped charge. Instructions for cutting pipelines with oil residues on the walls using cumulative cord charges (ShKZ) 84-988-84 IE1. - Ufa: VNIIMT oil. - 1988. - 20 p.], Which are widely used at present.

ShKZ are a polymer shell obtained as a result of extrusion from a polymer material filled with explosive. ShchKZ charges have high elasticity, flexibility and the absence of fragments.

The disadvantages of the currently widely used ShKZ charges are:

- a 2-3-fold increase in the weight of explosives in comparison with UKZ in a metal shell;

- increased fire hazard due to the presence of polymer in the explosive charge;

- the effectiveness of the ShKZ is 2-3 times lower than the UKZ with the same mass of explosives.

- at low temperatures, you must first give the charge the desired shape, otherwise in the cold it loses its elasticity and becomes brittle, brittle.

In addition, ShKZ charges are 2 ... 3 times more expensive than the proposed charges

The practice of these activities usually involves shutting down the section of oil pipelines to be dismantled and draining the oil. At the same time, non-removable residues of oil or oil products remain on the walls of the oil pipeline, which imposes additional requirements for ensuring the fire safety of blasting. Explosive technology for cutting pipelines with oil residues on the walls in accordance with the instructions for the production of these works is carried out in two stages. At the first - preparatory stage - the disassembled section is cut off by linear valves, the foundation pit is prepared for opening the pipeline at the place of work. Next, the insulation of the ShKZ installation sites is cleaned and holes are cut with a diameter of at least 100 mm to introduce foam generators and control the filling of the internal cavity of the pipeline with foam. The location of the holes relative to the explosive cutting device is selected so that the length of the filling zone of the internal cavity of the pipeline with gas-liquid foam is at least 7 m in each direction from the cut plane.

As a prototype of the proposed technical solution was selected ring cumulative pipe cutter [Gushchin V.I., Evstigneev N.P. Explosive method of cutting pipes // Construction of pipelines. - 1986. - No. 11 - P.27-28.], Which was used for cutting trunk pipelines

An explosive pipe cutter of this design consists of two half rings of profiled copper shells, the so-called elongated cumulative charges (UKZ), UKZ are produced by the method of multiple drawing of pipes through a die. This method is characterized by high laboriousness, and the resulting products have low ductility, due to the hardening obtained by the metal in the manufacture.

Technical characteristics of the annular pipe cutters are shown in table 1.

The nomenclature includes nine sizes with a length of 1 to 3 m, differing in geometric dimensions, explosive mass per linear meter.

Table. one Size Charge width (diameter of tubular workpiece), mm Wall thickness mm Depth of cut (not less), mm Explosive mass, g / l.m TrKKN 16.5 × 1420-35 20 (18) one 17 210 TrKKN 16.5 × 1220-35 20 (18) one 17 210 TrKKN 16.5 × 1020-35 20 (18) one 17 210 TrKKN 16.5 × 720-35 20 (18) one 17 210 TrKKN 19.5 × 1420-35 22.5 (20) one twenty 230 TrKKN 19.5 × 1220-35 22.5 (20) 1,5 twenty 230 TrKKN 21.5 × 1420-35 22.5 (20) 1,5 22 410 TrKKN 21.5 × 1220-35 22.5 (25) 1,5 22 410

The detonation velocity of the explosive filler is not less than 7000 m / s, the initiation of detonation from ED-8.

Pipe cutting using ring shaped charges is as follows. In the explosion of a cumulative charge, a gas-metal jet is formed, which instantly cuts the pipe wall. The strongest cutting action of the jet occurs at a certain distance from the charge, i.e. in focus, where it has the highest speed and density. The magnitude of the focal length depends on the parameters of the cumulative charge extraction and the type of explosives used. To create a given focal length around the perimeter of the pipe, a retainer is mounted on the UKZ. The installation diagram of the annular pipe cutter is shown in Fig. 1.

The device contains 1 - wall of the pipeline, 2 - ring charge, in the form of two half rings, 3 - lock retainer half rings, 4 - lock with a slot for an electric detonator, 5 - electric detonator. 6 - copper shell of the UKZ charge, 7 - explosive, D - diameter of the pipeline.

A lock and a holder are put on one half-ring of a charge, and a lock and a lock on the other. Half rings are hung on the pipeline and connected using a lock, while the installation site of the pipe cutters is first cleaned of insulation to a width of at least 500 mm. The blasting method can be used for cutting pipes with a diameter of 210 to 1420 mm with a wall thickness of up to 20 mm. The radius of the expansion of fragments up to 300 m.

Disadvantages of explosive technologies using the above annular cumulative pipe cutters:

Data TRKKN can not be used when conducting separation operations dismantling, emergency recovery work, on trunk pipelines having a cross section in deviation from the circle. This device does not have a sufficiently reliable initiation system, due to the need to place the initiation system in places of thickening of the charge shell (see Figure 1).

In addition, it is difficult to fix the TRKKN at the focal length through the use of supports, especially at low temperatures.

The technology for manufacturing TrKKN charges, based on the drawing method, is not only low-productivity, but also leads to the appearance of a number of defects that reduce the quality characteristics of UKZ. In particular, due to the formation of hardening, which causes residual stresses in the metal, a reversal of the longitudinal cumulative groove relative to the end section of the UKZ occurs, which significantly reduces the effectiveness of the products. In addition, when drawing, the length of the initial billet increases several times, which can cause a rupture of the explosive charge continuity. Which ultimately leads to a decrease in the reliability of separation of pipelines.

The technical result of the proposed utility model is the creation of a technologically advanced and economical pipe cutter for emergency recovery work on trunk pipelines, including those having a deviation in external geometric dimensions.

The indicated technical result is achieved by the fact that the profiled metal shell with a cumulative recess angle of 87 ... 90 ° is rolled, each half-ring has an inflection, the length of which is 2 ... 3 times the width of the UKZ section, and the ratio of the height of the charge section (N) to its width (B) is in the range 0.74 ... 0.8, and the ratio of the cladding thickness (δ) to the size of the explosive layer (d) is 0.21 ... 0.25, and two detonators for initiation are placed at the bent ends of the UKZ, at the top of the cumulative lining, strictly along the axis of the charge.

Fig. 2 shows a pipe cutter with a cross-section along A-A in the form of a figure with a cumulative recess with an opening angle of 87 ... 90 ° with a width B and a height N., a shell thickness of 8, and an explosive layer thickness d.

Known methods for calculating the parameters of elongated-cumulative charges (UKZ), for example: Methods for calculating the formation of a cumulative “knife” are elongated charges with a wedge-shaped recess. Explosion physics. Edited by L.P. Orlenko // Moscow. - 2002. - P.273 ... 279. But in the UKZ calculated with its use the interval of the ratio of the height (H) of the charge to its width (B) is from 0.8 to 1.29, and the interval of the ratio of the shell thickness (δ) to the thickness of the explosive layer (d) is from 0.07 up to 0.28.

The proposed intervals of the ratio of the height (H) of the charge to its width (B) 0.74 ... 0.8, as well as the shell thickness (δ) to the thickness of the explosive layer (d) 0.21 ... 0.25 were obtained as a result experimental testing from the condition of obtaining the maximum depth of cut with minimum masses of explosive charge and shell metal using powdered RDX and HMX for equipment. When the parameters of the UKZ charge exceed the above intervals, the cumulative effect is significantly reduced or the mass of the explosive or metal shell increases.

The main stages of the manufacture of pipe cutters are as follows. Thin-walled pipes of the required diameter are filled with powdered explosives; when equipped with explosives, vibrocompression is simultaneously carried out. Fully equipped pipes are corked on both sides. The lining and the outer surface of the UKZ are formed with the help of rotating rollers of a specific, necessary configuration on a special rolling mill. The rolling speed is determined by the safety requirements of the BB seal. This method allows you to make UKZ in one step rolling instead of eight to twelve when drawing

The effectiveness and stability of the action of UKZ is largely determined by the quality of the process of collapse of the linings, where the symmetry of the process of initiation of the explosive charge is of particular importance, the detonator should be located strictly in the plane of symmetry of the UKZ. The smallest acceleration section length upon initiation from one of the open ends of the charge when the detonator is located in the middle of the explosive layer. In our case, the most stable and best results are obtained when the detonator is installed at the top of the cumulative lining strictly along the charge axis, in our case, at the bent end of the half ring. The length of the bent part corresponds to the size of the section where the charge detonation reaches the maximum mode for the given conditions and ensures the formation of the optimal “cumulative knife” from the shell.

As a result of the influence of the “cumulative knife" formed during the explosion of the charge, a cut is formed on the structure, the depth of which depends on the design characteristics of the UKZ and the conditions of its interaction with the obstacle.

The proposed design is simple to install, does not require installation of UKZ on the pipe with clamps that provide a focal length around the perimeter of the pipe, especially in difficult conditions. The pipe may have a complex profile, this design allows the dismantling of pipes of any section. This device is reliable and safe. Pilot production of pipe cutters has been established.

Claims (1)

An explosive pipe cutter, consisting of two elongated cumulative charges (UKZ) in the form of half rings, forming a ring when mounted on a pipeline, made of a profiled metal shell with a cumulative recess filled with a highly blasting explosive, and an initiation system, characterized in that the shaped metal shell with the angle of the cumulative recess equal to 87-90 °, made by rolling, each half-ring has an inflection with a length of the inflection section equal to 2 ... 3 dimensions of the width of the cross section UKZ, and the ratio The charge of the pipe cutter to its width is within 0.74 ... 0.8, and the ratio of the cladding thickness to the size of the explosive layer is 0.21 ... 0.25, and the detonators for initiation are located at the bent ends of the UKZ, at the apex cumulative lining, strictly along the axis of the charge.