RU2611549C1 - Butt joint of insulated pipes or shaped parts - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: compound contains an interconnected internal working pipe S and overlap mounted on the outer jacket pipe sleeve made of translucent plastic. Coupling is made of heat-shrinkable plastic translucent, and between the coupling and the outer pipe jackets embedded heating elements of the different colour from the colour of the wrapper tube are arranged.

EFFECT: insulation properties and preservation characteristics in joints areas over an extended period of time and increasing the life of the joint and pipeline systems.

7 cl, 6 dwg

Description

The invention relates to the field of construction and reconstruction of pipeline transport used in the power industry, utilities, oil and gas industry and is intended to provide hydraulic and mechanical insulation protection in one-piece butt joints of piping systems, for example, in heat, waterproofing.

A technical solution is known according to the patent RU 2513861 04/20/2012, designed to create an equal strength connection of tubular structures and pipelines from dissimilar materials, is a single piece of pipe corresponding to the configuration (profile) of the connected structures made of modified thermosets, where according to the invention the coupling is made of glass -, organo-or carbon fiber and a modified thermoset by winding along the entire length of the coupling with the same winding angle for connecting tubular structures, pipelines of the same material or with different winding angles for these compounds of dissimilar materials.

The known device is low-tech due to the fulfillment of the necessary conditions for connection, i.e. compliance with the same winding angles from the same material and / or different winding angles when making connections from dissimilar materials, as well as the presence of an annular adapter made with an increased winding angle.

A technical solution is known according to patent RU 2341717 of 05.16.2007, according to which the heat-shrinkable sleeve is a casing made of cross-linked polyethylene along the entire length, consisting of shrinkable ends with a thickness h and a middle part with a thickness H, while the casing is formed of a shrinkable sheet in a number of layers, and the layers of the casing are connected by glue.

The disadvantages of the known device are the complexity and low reliability of the structure made of sheet material, which in turn consists of a set of layers connected by means of glue. Due to the operation and contact of the coupling with the environment, for example, with the soil, the edges of the set of sheets are bent due to friction forces, which leads to the separation of the structure into individual sheet elements and depressurization of the entire assembly.

A technical solution is known according to the patent US 5869153 (A) - 1999-02-09 IPC B29K 105/02, B29C 61/06, B29K 105/16, B29K 105/32, according to which a hollow cylindrical product containing at least , one transparent part and one opaque part, while the transparent part is presented in the form of one or more strips and is made by molding or extrusion of a polymeric material having a shape memory.

The known device is low-tech, due to the presence of transparent and opaque parts in the design, the use of two materials (transparent and opaque), which necessitates the use of specialized, expensive equipment in the manufacture of the product. The presence of an opaque part in the structure does not allow visualizing the processes occurring under this part of the coupling, for example, how the activation of the adhesive material occurs and / or to see defects associated with the heat shrink technology (underheating / overheating), visualization of the internal placement of the connected products according to requirements and standards, is absent the ability to quickly identify errors for on-site repairs, etc.

The closest analogue of the claimed design is the solution described in the application EP 0114660 from 08/01/1984, IPC F16L 59/20, B29C 44/12 and representing a hollow transparent sleeve made of a transparent material, used when connecting two previously insulated pipes. The transparent coupling allows, without the use of special equipment, such as an ultrasonic device, to visually detect defects, for example, in the form of bubbles or voids that can form in the insulating material. Timely detection of defects allows you to eliminate them by drilling holes in the coupling, followed by filling the voids with insulating material through the drilled holes.

The disadvantages of the closest analogue are, firstly, the difference in the diameters of the connected pipes and the coupling, namely the larger diameter of the coupling and the smaller diameter or size of the products, which ensures the presence of a gap between the connected products, which requires additional sealing by heat-shrink rings. At the same time, the sleeve itself does not have heat shrink properties, i.e. shape memory effect.

Secondly, the disadvantage of the closest analogue is that when it is used, it is possible to control only the process of formation of a heat insulating layer, but there is no possibility to control the process of heat shrinkage of the coupling, which ensures the tightness of the connection.

This point is very important, since if defects occur at the junction of the coupling and pipes, moisture can penetrate precisely through the junction of the coupling with the previously insulated pipe. The service life and durability of the connection are significantly reduced, which affects the operational properties of the entire pipeline as a whole.

The claimed invention relates to the step of sealing joints of piping systems mounted from pre-insulated pipes. A pre-insulated pipe consists of a steel (or polymer) inner working pipe (hereinafter referred to as the working pipe) with centering supports, an external sheath pipe (hereinafter referred to as the sheathing pipe), an operational remote control system (hereinafter referred to as SODK) and an insulation layer, for example, from a layer polyurethane foam obtained from expandable components. Both ends of the working pipe extend beyond the shell pipe and the insulation layer, i.e. they are not insulated, which is necessary for future welding (technological indentation), and above this section after welding the working pipes, a sleeve is installed, the free space under which is also filled with a foaming composition to form an insulation layer.

The problem solved by the invention is to ensure the reliability of the hydraulic and mechanical protection of the joints of the joints of pre-insulated pipes, to provide the possibility of visual non-destructive testing of the one-piece coupling-pipe-shell connection at various stages of the formation of the connection (heat shrinkage, sealing, formation and polymerization of the insulation layer).

Improving the reliability of pipelines, within weaknesses such as butt joints, positively affects the technical characteristics of pipelines, thereby increasing the life of the pipelines, thereby reducing operating costs for maintenance, repair, maintenance and other maintenance costs. Despite the variety of couplings currently offered by various manufacturers and designed to insulate joints, a common feature remains that the joints of previously insulated pipes are sealed with adhesive materials of a dark color, which does not allow visualization of the processes. Even when using a translucent sleeve that allows you to monitor the formation of the insulation layer, there is no way to control the formation of the coupling-pipe-shell joint when using a welded joint, since in the closest analogue the sleeve is not heat-shrinkable, therefore, the weld between the sleeve and the pipe shell can be formed only after its compression by heat-shrinkable rings, overlapping the overview of the place of formation of the weld. In another analogue, the coupling has transparent longitudinal stripes alternating with opaque, which also does not allow it to be used to visualize the formation of an annular seam. The inability to control significantly affects the reliability of the joint sealing of pre-insulated pipes and the operational properties of the entire pipeline.

The problem is solved by using a heat-shrinkable sleeve, made entirely of translucent material (transparent, translucent) with a shape memory that allows visual and non-destructive testing of the welded joint between the sleeve and the pipe shell due to the light transmission of the sleeve material, through which you can see the formation of the permanent connection of the sleeve and shell pipes of previously insulated pipes, while a welded joint is formed at the expense of means (embedded elements) having a color of personal color of jacket pipe. To obtain a high-quality weld, the material of the heat-shrinkable sleeve and the material from which the shell pipes are made should preferably be the same, for example, polyethylene can be used.

In the claimed invention, it is proposed to use a coupling, which is a hollow cylinder made of translucent plastic, for example polyolefins, with a shape memory effect (heat-shrinkable sleeve), long enough to cover the insulated area (junction) with inlets for girth of the connected elements - pipe shells of two adjacent pre-insulated pipes.

The use of a heat-shrinkable sleeve, made entirely of translucent plastic with shape memory, for hydraulic and mechanical protection of joints of joints of previously insulated pipes, unlike existing analogues, allows visual non-destructive testing, for example, using a magnifying glass, which is possible due to the combination in one product ( sleeve) heat-shrink properties and light transmission, as well as the selection of the color of the embedded element, for example, contrasting, bright in relation to the color of the pipes -shells or just another color, well different from the background of pipe shells. In this case, in case of detection by the contractor of defects associated with the formation of a weld, it is possible to immediately fix the defect, i.e. carry out operational repairs.

Additionally, the translucent coupler may have at least one process opening for supplying components of the insulating material, air and reaction gases. Mostly the coupling has a circular cross section, and its length lies in the range from 0.1 m to 1 m.

The technical result achieved by the invention is to preserve the properties and characteristics of insulation at the joints of butt joints for a long period of time and increase the life of the joint and, accordingly, piping systems due to the formation of a reliable tight joint "heat-shrinkable sleeve-pipe-sheath", which is due to as follows:

1) while maintaining the ability to visually control the formation of the insulation layer, it is additionally possible to create and visual non-destructive testing of the integral welded joint "heat-shrinkable sleeve-pipe-sheath";

2) the level of quality of the coupling-pipe-shell joint increases, due to visualization of the processes of the coupling location, placement and functioning of the embedded heating element (joint defects are detected and eliminated at the stage of the weld formation), i.e. if necessary, repair of defective places is carried out immediately;

3) the technological process of sealing is reduced by eliminating the technological operation of crimping the joint;

4) due to the heat shrinkage of the coupling, the non-uniform gap between the coupling and the pipe-shell is compensated, which occurs under the action of gravity on an unfastened coupling, which freely rests on the connected pre-insulated pipes, which leads to the absence of a gap at the top of the coupling and its increase in the lower part of the coupling.

In addition, the technical effect of the use of the invention, unattainable by known analogues, is that the manufacture of the entire heat-shrinkable sleeve from a translucent material (transparent, translucent - matte) allows using simple optical means, such as a magnifier, to carry out continuous visual non-destructive testing of the main technological operation " Joint sealing ”, namely, to observe the process of heat shrinkage and the quality of compression of the heat-shrinkable sleeve of the pipe-shell, ensuring m sealing compound, identify and evaluate the presence of defects in one piece, welded connection. This effect is unattainable when using a technical solution - the closest analogue, despite the transparent coupling described in it. The lack of heat-shrink properties of the coupling does not allow for an inextricable connection directly to the sleeve of the sleeve pipe, and to control the quality of the weld. In the closest analogue, direct coupling of the coupling with the pipe-shell is generally not provided using means other than external compression of the coupling.

An additional advantage of using plastic translucent couplings is the elimination of overheating or underheating of the embedded heating element.

The optimal length of the proposed coupling for different types of insulated pipelines ranges from 0.1 m to 1 m.

The materials for the coupling are mainly translucent plastics with a shape memory effect, including mesh (crosslinked) polymers, for example polyethylene, which is associated with the widespread occurrence of heat-insulated pipelines with waterproofing in a polyethylene sheath pipe. Other translucent (transparent or translucent) plastics can also be used, allowing the manufacture of a product with a shape memory effect.

To increase the physicomechanical or operational properties, the materials from which the coupling is made can be filled, i.e. contain known excipients, for example, an antistatic agent, a nucleator, a stabilizer to protect against ultraviolet radiation, etc., in their recipe, or in their recipe.

Clutch blanks are made by various known methods, for example, by extrusion, injection molding, molding, and others.

In US Pat. No. 5,869,153 A known from the prior art, a heat-shrink sleeve for sealing has transparent and opaque portions. However, this technical solution allows you to control (visualize) only the longitudinal location of the joined elements, which is important for connecting electrical cables. This device is not intended for sealing and quality control of a permanent connection of a heat-shrinkable sleeve with a connecting element along the entire length of the annular weld. In the claimed invention, the heat-shrinkable sleeve is made entirely of translucent material, which, in combination with the selected color of the embedded heating element, different from the color of the shell pipe and the sleeve, allows to obtain a new property - visualize (control) the sealing process in dynamics with the formation of a weld, thereby ensuring stable quality at one of the initial stages of the coupling-pipe-shell connection and, if necessary, correct possible defects.

A new combination of features characterizing the invention, namely the use of a translucent heat-shrinkable sleeve and the color of the embedded heating element selected in this way, can ensure the achievement of the above technical result. The heat-shrinkable sleeve allows not only to form a connection to the sheath pipe by heat-shrinkage due to shrinkage of the sheath-pipe, but also, due to heat-shrinkage, to create conditions for making a weld without additional external devices that compress the sleeve. Due to the color of the embedded heating element selected in this way, in combination with the property of the coupling material, such as transparency or translucency (for thin-walled couplings), and the absence of interfering visual crimping means, the entire process of formation of the welded joint of the coupling with the pipe-sheath is effectively controlled, which collectively ensures the achievement of the above technical result. In addition, as in the closest analogue, in the process of implementing the method, it is possible to monitor the formation of a heat-insulating layer under the coupling.

The essence of the claimed invention is illustrated by drawings and explanation to them.

FIG. 1 - joint pipe prior to placement of heat-shrinkable sleeve; overlaid heating pipes are installed.

FIG. 2 is an isometric view of the joint of pre-insulated pipes after heat shrinkage of the coupling.

FIG. 3 - connections heat-shrinkable "sleeve-pipe-shell" with a defect in the weld "shell", a local cutout, in place A.

FIG. 4 - connection “coupling-pipe-shell” with a defect in the weld - uneven seam, local cutout, in place A.

FIG. 5 - connection "sleeve-pipe-shell" with defects in the weld in the form of accumulation of pores and foreign inclusions, local cutout, position A.

FIG. 6 - connection "coupling-pipe-shell" with a built-in heating element with leads for connection, in place A.

In the drawings, the positions indicated:

1 - inner working tube;

2 - outer pipe-shell;

3 - place of installation of embedded heating elements;

4 - heat-shrinkable sleeve made of translucent plastic with a shape memory effect;

5 - a layer of thermal insulation;

6 - weld;

7 - embedded heating element;

8 - points of connection to an autonomous energy source;

9 - defect of the connection "heat-shrinkable sleeve-pipe-shell" in the form of a "shell";

10 - defect of the connection "heat-shrinkable sleeve-pipe-sheath" in the form of an uneven seam;

11 - defect connection "heat-shrinkable sleeve-pipe-shell" in the form of an accumulation of pores and foreign inclusions.

In order to simplify the images of the construction of the butt joint of previously insulated pipes or fittings, auxiliary elements in the form of centering supports, conductors of the insulation layer monitoring system (SODK), etc., are not conventionally shown.

Pre-insulated pipes include an inner working pipe 1, an outer sheath pipe 2, and a thermal insulation layer 5.

During the installation of the pipeline, pre-insulated pipes are connected in series. Before joining the working pipes, a heat-shrinkable sleeve 4 in a protective case, made completely or partially from translucent plastic with a shape memory effect, is put on one of the joined pre-insulated pipes, placing the sleeve 4 with a gap over the pipe shell 2 at some distance from the junction. The diameter of the heat-shrinkable sleeve 4 before its heat shrinkage may exceed the diameter of the outer tube-shell 2, for example, by 1-50%, preferably by 1-30%. The heat-shrinkable sleeve 4 can be made with a wall thickness from 1 mm to 23.5 mm (usually no more than 20 mm), and a transparent material must be selected to enable visualization of the processes occurring under the sleeve. If the wall thickness of the heat-shrinkable sleeve 4 is small, not more than 1 ÷ 10 mm, the sleeve can be made of white (or other color) opaque material.

Technological indentation of the working pipe 1 extends beyond the pipe-shell 2 and the insulation layer 5, mainly from 100 mm to 350 mm. The working pipes 1 are installed end-to-end and welded together to form an airtight integral connection.

The pipe shell 2 and the ends of the insulation layer are located at a distance from each other, equal to the sum of the lengths of the technological indents of the joined working pipes 1.

After welding the working pipes 1 and confirming the tightness of the weld, additional work is carried out (cleaning the connected surfaces from dirt, degreasing, connecting the conductors of SODK, etc.).

For the connection “coupling-pipe-shell” on the prepared surface along the edges of the pipe-shells 2, the embedded heating elements are installed and fixed in the places indicated by pos. 3, which differ in color, or brightness, or shade from the color of the pipe-shell 2. Mortgages heating elements 7 are equipped with leads 8 for connecting an autonomous energy source.

The preferred color of the pipe shell 2 is black.

Next, remove the protective cover from the coupling 4 and push it into the working position on the joint, while the light transmission of the coupling contributes to its exact location relative to the previously fixed embedded heating elements 7. The heat-shrinkable coupling 4 is positioned so that it is mounted above the mating pipes-shells 2 above the embedded heating elements 7.

An electric embedded heating element 7 is used, as a rule (but not necessarily), in the case of installation of pipes of medium and large diameter, for example, with a diameter of more than 300 mm. To form a coupling-pipe-shell joint, the embedded element is heated by a weld seam 7, connecting an autonomous energy source to it through terminals 8, and the sleeve 4 is shrunk. Using the sleeve 4 allows the use of a translucent material for the manufacture of the sleeve, visually, non-destructive way to control the process of sealing, and in case of detection of defects identified for example by simple means, for example using a magnifying glass, repair the integral connection between the couplings toy 4 and shell pipes 2.

The joints of the coupling 4 with the outer surface of the pipe shell 2 are closed by a heat-shrinkable tape that overlaps the joint of the coupling 4 with the outer surface of the pipe shell 2 near the end of the coupling 4. As a result, the connection of the coupling 4 with the pipe shell 2 is sealed twice. The first seam is formed by a welded joint, and the second due to the shrinkage of the heat-shrinkable tape, which prevents the bending of the coupling along the edges and, as a result, protects the weld that connects the sleeve to the pipe-sheath from mechanical action of external forces.

In FIG. 3, 4, 5 show possible defects of the permanent connection heat-shrinkable sleeve 4 - pipe-shell 2, which are easily detected by visual inspection if the invention is used to seal the joint of pre-insulated pipes using a transparent (translucent) sleeve of the embedded heating element 7, different in color compared to the shell pipe 2.

In FIG. 3 shows a joint defect heat-shrinkable sleeve 4 - pipe-shell 2 in the form of a "shell" 9.

In FIG. 4 shows the coupling-pipe-sheath joint with a defect in the form of an uneven seam 10.

In FIG. 5 shows the connection heat-shrinkable sleeve 4 - pipe-shell 2 with defects in the form of an accumulation of pores 11 and foreign inclusions.

Claims (7)

1. The butt joint of pre-insulated pipes or fittings, including interconnected internal working pipes and a lap fastened on an outer pipe-shell, a sleeve made of translucent plastic, characterized in that the sleeve is heat-shrinkable from translucent plastic, between the sleeve and the outer pipe-shells of connected pre-insulated pipes are embedded heating elements that are different in color from the color of the pipe-shell. 2. The butt joint according to claim 1, characterized in that the joints of the heat-shrinkable sleeve with the outer surface of the pipe shells are closed with a heat-shrinkable tape overlapping the joint of the heat-shrinkable sleeve with the outer surface of the outer pipe-shell near the end of the heat-shrinkable sleeve. 3. The butt joint according to claim 1, characterized in that the heat-shrinkable sleeve made of translucent plastic with a wall thickness of 1-23.5 mm is made transparent. 4. The butt joint according to claim 1, characterized in that the heat-shrinkable sleeve made of translucent plastic with a wall thickness of 1-10 mm is made matte white. 5. The butt joint according to claim 1, characterized in that the diameter of the heat-shrinkable sleeve before its heat shrinkage exceeds the diameter of the outer pipe-shell by no more than 1-50%. 6. The butt joint according to claim 1, characterized in that the diameter of the heat-shrinkable sleeve before its heat shrinkage exceeds the diameter of the outer pipe-shell by no more than 1-30%. 7. The butt joint according to claim 1, characterized in that the wall thickness of the heat-shrinkable sleeve does not exceed 20 mm.

Images