Pipe centralizer: overview, characteristics, application. Centralizers for fixing and welding pipes Types and their differences

Perfect quality. To facilitate this process and improve the quality of execution, pipe centralizers have been developed and used. It is very difficult to connect the two elements by eye. This device is used by specialists who work on the laying of trunk and local pipelines. But the centralizer will also be useful for home craftsmen who are faced with the need for welding.

In addition to their immediate task, these devices can solve another equally important problem. So, the pipe centralizer is able to ensure the most accurate connection of the edges of the two elements, not only before welding, but also during the process itself. This greatly speeds up and simplifies the work.

Centralizers. Features and Applications

Work on laying a reliable pipeline does not begin with high-quality and professional welding, as many think. No matter how skilled the welder is, it is impossible to get good results without preparatory measures. It is necessary to adjust the alignment of the two pipes before welding.

It is especially important in the welding process to ensure the accuracy of the joining of two cylindrical trunk products used in gas transport systems, when pumping oil products, as well as for transporting chemical and other substances hazardous to humans. In this case, devices that allow you to get an impeccable connection quality are not a pleasant addition, but a necessity.

The range of sizes of these tools is quite extensive. Centralizers for pipe welding, depending on the type and overall dimensions, are designed to work with products with a diameter of 25 to 1600 millimeters. Individual tools can connect more impressive designs. The diameter of such products can be up to 2 m.

Any device for welding pipes avoids another important problem. Due to the rigid girth of the body, the device is able to prevent unnecessary movements of the element during welding. If this is neglected, then in the future, even with the application of minimal loads, the seam runs the risk of bursting.

Device, device design

A pipe centralizer is a mechanism consisting of thrust elements and components that hold the parts to be connected in a stationary state. The latter are clamped with a universal clamp. And with the help of fine tuning and level control, their connection is configured.

Main types of centralizers

All mechanisms that are on sale today can be divided into two categories. These are internal centralizers and external ones.

Outdoor equipment has the designation "CN". These systems are designed to be mounted on the outside of mating elements. Regardless of their overall dimensions, they are easy to operate, easily mounted on a pipe and allow for alignment as quickly and efficiently as possible. The external devices are the wide liver of the centralizers. There are eccentric, link, hydraulic and other configurations.

Internal pipe centralizer, designated "CV". It is a hydraulic unit. Equipment of this type expands the edges of the pipes to be connected from the inside, pushing the media towards each other. The advantage is the ability to use the tool for products of different diameters.

Outdoor

The external centralizer for pipes is a large-sized clamp. The latter, by gripping the cylinder, firmly holds the parts to be joined in a fixed, coaxial position. If we compare external devices with internal ones, then the first ones are easier to install and operate.

Another important feature of mechanisms of this type is the ability to straighten edges that have an irregular rounded shape (like an ellipse). If this defect is not eliminated before welding, then the quality of the future seam will be a big question. In this case, the strength of the product deteriorates significantly. Depending on the characteristics of the pipe (its wall thickness and outer diameter), centralizers are divided into several more types. We will consider each of them below.

Link

Such a centralizer is considered to be the simplest in design. The fixture is a multifaceted design with several links. Depending on the size of the pipes to be connected, the links can have the same or different lengths. The number of links depends on the outer diameter of the part.

This equipment is widely used for pipes from 50 to 1500 millimeters in diameter. The device is fixed to the surface using special clamps.

Hydraulic centralizer

This is a modification of the standard link equipment. The differences are that they are tightened after installation on the part not by hand, but with the use of a jack. Due to this, the pipe joining is improved. The mechanism compresses the cylinder with great effort, which in the best way affects the quality of the welded seam. The device is designed to work with diameters from 720 to 1620 millimeters.

Chain centralizers

This modification is used to eliminate pipe ellipse. It is supposed to use a jack of an electric or pneumatic mechanism. This group of chain devices combines several types of devices that work by tightening a chain around the pipes to be connected. Among the advantages is versatility. Working diameters - from 90 to 1000 millimeters.

Eccentric centralizer

Such centralizers for pipe welding are used with products of large diameters. The device is based on two steel arcs. Unlike the link mechanism, where the elements are fixed using special hooks, here, in the process of tuning for a specific pipe, they are pulled together. This is done using an adjusting jumper.

It should be noted that eccentric centralizers can be used to work with pipes of different diameters. You can connect products of different lengths. It is very comfortable. But these mechanisms are more expensive.

Features of internal centralizers

This type of fixture is more complex than outdoor systems. In this case, the inner centralizer acts on the pipe walls from the inside.

These systems function as follows: to special presses (and these are the working bodies of the centralizer), which are located in two rows along the outer diameter, the force is transmitted with the help of hydraulics. With this force, the pipe is bursting with presses from the inside.

Due to this, a more reliable and perfectly coaxial fixation of the product is achieved. This position is held until the end of pipe welding. Due to the powerful hydraulic force that is applied to the presses, this equipment perfectly copes with the tasks of correcting ellipse in the direction of the correct shape.

When installed in a pipeline, this centralizer is attached to the edge of one piece. Then the second section slides onto the mechanism. At the moment of fixation of two pipes, a gap remains between their ends, which is necessary for the welding process.

The device moves inside the line due to a special mechanical bar. To pull out the mechanism, which has a large mass, special tools are used. The centralizer is moved along the entire pipeline. Therefore, this auxiliary system is used for laying large highways. Welding work is carried out without interruption.

Other types

Along with the most popular and widely used equipment, there are less common and specific devices:

• arched;
• centralizer-clamp for pipes;
• spring, which are used with casing pipes in wells;
• mechanisms for polypropylene products.

The Clamping Centralizer is used to work with small pipes. This is the most popular variety and is suitable for domestic use. These devices are affordable and compact in size. The pipe pliers are easier to use. The clamp can be rectangular (trapezoidal) or round. The bottom element is usually flat.

The arch-type centralizer is the simplest. It consists of two terminals. They are pulled together manually or by hydraulic pumps. The scope of their use is small pipes up to 900 millimeters in size.

Features of choice

A suitable device is selected according to certain parameters. The first of these is diameter. Internal centralizers are more often used for working with large pipes. Outside - on the contrary, for small parts. Also, the choice depends on the material. If this product is with a polyurethane coating, then it can be cooked only with the use of internal equipment.

If you need to lay a small private pipeline, then a simple chain model is enough. In the case where the device will be used constantly, choose a suitable link or eccentric equipment.

An important parameter is the pressure of the contents of the pipe on the inner surface. At a pressure above 5 atmospheres, centralizers with a hydraulic clamp are needed to install it.

Finally

This is what these devices are. With their help, the process of laying pipelines will be significantly accelerated and simplified. And the accuracy and reliability of the weld will be at a high level.

For welding of fragments during the installation of the pipeline, specialized tools are used - pipe welding centralizers. This article describes their structure, classification and features.

Device

Different types of centralizers differ significantly in design. However, in any case, it is made up of thrust and fixing elements.

The main qualities of centralizers include:

• fixation reliability;
• the accuracy of their combination;
• ease of use;
• durability.

Application

Centralizers have a wide range of applications. This is due to the fact that they are designed to weld pipes of various types and diameters. In view of this, they are used in the assembly of pipelines in the utilities and oil and gas fields. Centralizers are used to fix adjacent pipeline fragments during welding.

The relevance of these tools is determined by the great complexity of combining the connection of fragments of main pipelines by welding, especially with a large diameter. This is due to sagging due to the low rigidity of the connected fragments. This must be avoided by ensuring alignment. Otherwise, the quality of the connection will be significantly reduced. Moreover, it should be borne in mind that alignment does not always mean parallelism.

Fragment fixation ensures stable dimensions of the weld zone. In addition, if a centralizer is used for welding, drops are not formed on the inner side of the joint, causing flow turbulence and increasing resistance during pipeline operation. That is, these defects worsen the hydraulic parameters, as a result of which more powerful pumping equipment is required.

Internal centralizer used for welding pipes with polyurethane foam coating used in main heating and water supply networks. This material acts as insulation and serves to place the cable that monitors the condition of the pipeline. A heat-resistant shell is applied over it. Therefore, welding is only possible from the inside.

Advantages and disadvantages

The main advantages of centralizers include:

• improving the quality of welding due to precise positioning and fixation, which ensures a long service life;
• reduction in labor costs;
• mobility;
• low cost;
• multifunctionality, consisting in applicability for pipes of different types and sizes.

The main disadvantage of centralizers is considered to be a slight increase in the cost of work. In addition, many industrial models are characterized by a large mass (up to hundreds of kg). Therefore, their use requires lifting devices. It also makes work more difficult and expensive.

You can also match the exterior and interior views.

Tools of the first type are characterized by the following advantages:

• small dimensions and weight for most models;
• ease of use;
• the ability to use under any conditions.

The main disadvantage is the sketchy work, due to the need for constant movement of the tool.

The main advantage of internal centralizers is to ensure continuous welding. However, these are large and heavy tools of complex construction, requiring the use of lifting equipment.

Models and prices

The choice of the centralizer is based on a number of criteria.

• Pipe diameter. First, each type of tool is designed for a specific diameter range. Secondly, for thick parts (more than 800 mm), rigid models (multi-star or arched) should be used, and for smaller diameters, eccentric options are suitable.
• Requirements for the quality of welding. In some cases, there are limits for connection defects (including ellipticity). Chain models provide the best welding quality.
• Ultimate pressure. To create the most durable weld seam, hydraulic clamping centralizers should be used.
• Pipe material. In this respect, the considered tools of all types are universal, but the exception is work with polypropylene pipes. In this case, internal variants are required.
• Versatility. Chain models are considered the best in this indicator.

The cost of centralizers varies widely. So, the simplest external multi-link models with a manual drive can be purchased for 1.5 thousand rubles, while the price of internal hydraulic ones is about 350 thousand. Thus, the cost is determined by the design, purpose, and also the brand.

Of the manufacturers of these tools, Vietz and Clamp stand out in terms of quality.

It should be noted that the simplest household centralizer is easy and inexpensive to create on your own.

The most important stage in the installation of the pipeline is the welding of individual pipe fragments into a single whole. This work is carried out using special devices that allow them to ideally position them precisely relative to each other - pipe centralizers.

What does the device consist of and how does it work

The device is a mechanism that consists of thrust elements and devices that keep the pipes stationary during welding. An approximate diagram of the device is shown in the figure.

The advantages of using are as follows:

• allow accurate welding of pipes, which reduces the risk of rupture and ensures a long service life of the pipeline;
• these are mobile mechanisms that can be easily carried for pipe welding in different places;
• they are mostly affordable;
• they are multifunctional, since they allow you to work with different types of pipes (steel, polyurethane foam, etc.);
• they connect pipes of almost any diameter. They are especially needed for work on the installation of trunk pipelines for transporting water, oil or gas. Even small deviations in these systems are fraught with serious consequences.

Models and prices

An overview of prices for some models is presented in the table below.

The run-up in prices is due to several reasons:

• Purpose of the device- professional is much more expensive than domestic.
• Design features(presence or absence of a hydraulic drive).
• Manufacturer brand.

IT IS INTERESTING. For domestic purposes, it is quite possible to make a pipe centralizer with your own hands. For him you will need improvised means and tools that are easy to get. In addition, this option will cost much less than the purchased one.

Kinds

The division by type is based on different characteristics:

1. according to the peculiarities of the location of the centralizers relative to the pipes being welded - internal and external;
2. by the method of fastening to the pipe during its welding - chain, eccentric, arch type, clamping and link (multi-link);
3. Finally, according to the spheres of application, centralizers can be conditionally divided into household and professional ones. In the first case, they often work in manual mode, are small in size and are used in laying a domestic water supply system (for example, in a country house). In the second, we are talking about complex, expensive mechanisms that ensure the laying of trunk pipelines of any diameter and in almost any climatic conditions.

Outdoor and indoor

The devices can be used for welding pipes of almost any diameter. If the dimensions are small (usually from 20 to 2000 mm), then the device is attached around the pipe, and then we are talking about an external centralizer.

External centralizer

In essence, it is a pipe clamp that grabs their surfaces and ensures a stationary position during installation and welding.

An example of using this equipment in work can be found here.

External centralizers for pipe welding have their own undeniable advantages in comparison with internal ones:

1. they are lightweight and small in size, so they can be easily moved to any place;
2. allow you to work in any weather conditions (from -60 to +60 degrees Celsius);
3. provide high-quality welding of not only 2 pipes, but also entire water pipes;
4. mounted on pipes and dismantled from them quickly and easily.

The only significant drawback of such a device is that welding work has to be carried out with short interruptions - first the seam is made on a free surface, then the device is moved and a new shock is made, and so on.

Internal centralizer

If it is required to weld pipes of large diameters (as a rule, more than 2000 mm), then internal pipe centralizers are used in the work, which are not mounted on top of them, but are placed directly inside, resting tightly against the surface.

The location of the inner pipe centralizer is as follows.

Since such equipment is intended for the installation of wide pipelines, its dimensions are also very large. Accordingly, the internal devices can only be transported by transport.

However, they also have their own indisputable advantage in comparison with external ones - since they are installed inside the pipe, the welding work can be carried out continuously.

Installation work is always carried out using additional lifting equipment, as shown in the video.

The standard equipment of the equipment is represented by the following elements:

• barbell;
• pipe presses;
• cable;
• pressure gauge for pressure control;
• electric drive pump;
• headlights.

NOTE. For welding, an inflow of fresh air is required, which cools the inner surfaces, thereby preventing them from overheating. Special fans help to ensure this process. Usually they are not included in the basic delivery option, they are ordered additionally at the request of the buyer.

IT IS INTERESTING. Internal centralizers for welding work are not always used in the operation of large diameter pipes. They are also effective when installing small (up to 500 mm in diameter) pipes, since they ensure their precise installation with each other. The thrust in this case is not achieved by hydraulics, but by means of conventional springs, as shown in the figure below. In this case, the drive is operated manually by turning the handle.

The principle of operation of the mechanism is based on a hydraulic jack (shown in the figure in small and close-up), which is driven by electricity, therefore it is often called an electro-hydraulic pipe centralizer.

This device has two important functions:

• Provides maximum thrust to prevent pipe vibrations during welding.
• Eliminates the deflection of the installed pipe, which can occur as a result of lowering the soil or due to the weight of the pipe itself.

The most important technical characteristic of the device is the diameter of the centered pipes, on which the mass of the centralizer itself depends. These data are shown in the table below.

Device drawings

Centralizers by the method of attachment to the pipe

External pipe centralizers can be attached to the pipe in different ways. Accordingly, the following types are distinguished:

Video instruction for using the centralizer-clamp

Pipe mounting procedure

The principle of mounting the centralizer does not fundamentally depend on the specific type and model of the device. However, there are some peculiarities of indoor and outdoor. They are related to the preparation of the pipe for welding.

Installing the internal centralizer

In order to properly fasten the device of the internal type to the pipes that need to be welded, the following steps should be taken:

• First of all, you need to carry out preparatory work - the joints of the pipes to be welded must be well cleaned of paint, clogging, rust and other foreign inclusions. This is done using tools or special chemicals. In 1 case, the most popular grinder, on which a metal brush is planted.

You can also use a conventional sander.

Video example of pipe stripping before welding.

In the case of old, difficult to remove paint stains, you can also use a building hairdryer - under the influence of hot air currents, the paint begins to soften, after which it can be easily removed with ordinary emery.

At home, you can use sandpaper for cleaning or resort to using household chemicals - for example, you can dissolve the paint with acetone, and then wipe the pipe dry with a clean rag.

IMPORTANT. Work with acetone should be done only outdoors in moderately warm weather and away from sources of open fire, since the substance is toxic and flammable (+40 C is sufficient).

• After carrying out a complete cleaning of the joints, you need to fix the inner centralizer on the edge of one of them.
• Another pipe is tightly pushed up to the first, after which the limit stop is created using a spring mechanism (manual feed) or hydraulic drives.
• Make sure the connection is correct and start welding.

Installing an external centralizer

The installation of this device is fundamentally different in that it is fixed on the outer surface of the pipe. Accordingly, the sequence of actions will be somewhat different:

• At the beginning, the joints are also cleaned, as described above.
• Then 2 segments are brought to each other, and the centralizer is put on over them at the junction.
• The connecting bolts are inserted into special holes and tightened firmly.
• Finally, the reliability of the installation is checked. and welding work begins.

Installation video

Specifications

When choosing a specific model of centralizer for pipe welding, you need to proceed from several parameters:

• The diameter of the pipe is usually internal for large, external - for small (up to 900 mm).
• Pipe material - for example, if they are covered with polyurethane foam (so-called PPU pipes), then they can only be welded using an internal device.
• Scope of work - if we are talking about laying a small private water supply system (for example, in a country house), then a chain model is sufficient, which is the most affordable. If we are talking about professional work, then it is better to choose among link and eccentric models. The latter are the most expensive, but at the same time they are more reliable and serve longer.
• The pressure of the contents of the pipes on the inner surfaces - if it is more than 5 atmospheres, then for the installation of such pipelines a device with a hydraulic clamp is required.

NOTE. The main factor influencing the choice is the pipe parameters (material, diameter, strength). This is what you should proceed from when buying a centralizer.

Video example of assembling a centralizer with your own hands

Other devices for fastening pipes when welding them

Along with centralizers, which are often used in a professional environment, there are several other devices that allow you to reliably fix joints during welding. The main purpose of these devices is to maintain the pipe in the desired position by creating an abutment against a solid surface. They are divided into several varieties:

Chain vise is a separate class of pipe fixing devices. The mechanism is based on a chain, which is made of extremely durable types of alloy steel. A characteristic feature of the device is the ability to work with pipes of any diameter due to a simple adjustment mechanism - lengthening or shortening the chain.

They are classified into several groups depending on the work performed:

Finally, a whole class of multi-row vices is distinguished, which are used in special cases, for example, when drilling wells. They can replace several conventional vices. The chain is designed in such a way that the vise does not get stuck even under maximum load. So that the surface of the pipe does not receive severe damage from the pressure of the chain, it is equipped with steel liners, which can be replaced as they wear out.

Chain vise is a fairly popular pipe centralizer because it has obvious advantages:

• They are simple and easy to use, even among hobbyists.
• They serve for a long time and practically do not require maintenance, except for periodic lubrication of the working surface of the chains.
• Fairly affordable (below is a comparative table with an overview of some models).

A short video overview of different types of vice from one of the renowned manufacturers RIDGID can be seen here.

Vise at home: do it yourself

Of course, in extreme cases, you can do with home-made devices for fixing pipes. Here are some of them:

However, using artisanal production methods, you need to consider safety precautions:

• First of all, you need to understand that welding is a source of elevated temperature, which means that all structural elements should not be made of flammable materials - for example, wood.
• The main requirement for a pipe centralizer is fastening rigidity and structural reliability. It is worth remembering that during the welding work, the pipe will inevitably sway, therefore, the homemade system must initially be very strong.
• All handicraft tools are suitable only for small pipes, mainly for making straight joints between them. If you have to work with large, heavy pipes or perform complex joints, then such tools will definitely not work.

Consequences of improper welding

In the case of the wrong choice of the centralizer or non-observance of the rules for working with it, a whole complex of consequences can arise, which are called welding defects. These include:

• cracks;
• pores, small cavities;
• lack of penetration as a result of incomplete coverage of the metal surface by welding machines;
• various deviations of the seam structure - excessive bulge, displacement, undercuts and others.

All these defects will inevitably lead to the fact that the pipe will not last long. The consequences are aggravated by the nature of the operation and external factors:

• pressure drop of internal contents (water, oil, gas, etc.);
• temperature difference (internal and external);
• the effect of corrosion.

Penetrating into microcracks, water and air significantly accelerate the processes of metal decomposition (corrosion). This will lead to the fact that the pipe will soon leak, the pressure in the system will drop, and accordingly, a breakthrough may occur. Therefore, a competent choice of a pipe centralizer and its correct operation at all stages of welding is an essential condition for the installation of pipelines of all types.

When welding pipelines, it is necessary to maintain a straight line or a certain angle of direction of the pipes. To ensure that the edges of the pipes are evenly connected along the entire circumference, devices called centralizers are used. Centralizers for pipe welding are used both when laying main pipelines and when working in industrial and residential premises.

Centralizers purpose:

• acceleration of the welding process;
• the ability to connect pipes and pipeline fittings (bends, transitions, tees, expansion joints), while maintaining the required connection angles;
• prevention of deviations of pipes by the angle of inclination or divergence along the plane of the section;
• the ability to connect pipes by weight, using lifting devices and construction equipment;
• fixation of pipes to maintain the required gap, which ensures the proper quality of the weld;
• the ability to connect not only steel, but also copper, polypropylene and other pipes.

If at home the deviations of the pipe connection angle by 0.5-20 will not be critical, then during the construction of many kilometers of pipelines it is required to ensure the most direct direction of the pipeline. Often the pipes are laid on pre-prepared supports.

Kinds

Regardless of size, there are two main types of centralizers - internal and external. The abbreviation for centralizers allows you to determine its type (letter code) and the maximum pipe size (digital code) that they can connect.

Internal

Internal centralizers (CV) provide access to the entire outer surface of the pipes being welded and allow you to apply a continuous seam without preliminary spot joints (tacks). They allow you to correct small dents and deviations from the cylindrical shape, alignment of the edges in the center of the pipe.

By design features, several types of such devices can be distinguished:

• Scissor (CVN) - designed to connect pipes of different diameters.
• Manual with expanding wings (CVR) - for connecting small diameters, the spacer is carried out by means of a manual pressure screw.
• Hydraulic (CVG) - allow you to connect several pipes by moving the device inside the pipeline using a special rod.
• Self-propelled hydraulic - they move inside the welded pipelines due to remote control.

The spacers of such centralizers are carried out by means of devices called presses. The clamps are installed in the pipe and, using a hydraulic (or manual) drive, fix the pipe joints. The hydraulics of the apparatus corrects for deviations of the pipe from the shape of the correct circle.

The centralizer is installed on the edge of one pipe, and the other pipe is pushed onto it until the required clearance is obtained. Then the equipment fixes the working position of the pipes and the seam welding process begins.

Since welding requires an air flow that cools the metal surface, some internal centralizers are equipped with fans. Or, if necessary, a technical fan is used.

Outdoor

External centralizers (TsN), which are not inserted into the pipe, are grips with brackets, which are connected by hinges. Such devices allow joining pipes of different diameters, elbows, bends and other fittings. Unlike the mechanisms used inside the pipe, such centralizers allow you to neatly join the outer edge of the pipes, but are poorly suited for situations where precise alignment of the inner edges is required.

For large-diameter pipes, massive centralizers are used, which require special equipment (cranes, manipulators). The main types of such devices are:

Link (CZN) - polyhedrons, which, by installing or removing additional ring-links, can be adjusted to fix pipes of different diameters, the tie for fixing the centralizer is made by means of a pressure screw. Thus, one centralizer can be used both for pipes with a diameter of 50 mm and for pipes with a diameter of up to 2 meters. Modifications equipped with a hydraulic jack (TsZN-G) allow to increase the tie force, improving the quality of the connection and leveling the contours of the pipes being connected;

Chain (CNTs) - the most tightened around the pipes to be connected, consist of two components - a chain and a tensioning mechanism,

Eccentric (TsNE) - due to the design, representing arcs of different diameters and an adjusting bridge, they allow to connect pipes of different diameters, pipes with bends and adapters. The working diameters range of such centralizers is from 89 to 426 mm,

Arched (TsAN, TsAN-G) - are made in the form of arched sections, connected by hinges, pulled together using a hydraulic drive. Can be equipped with a straightening device for aligning mismatched ends by moving the stops. Such centralizers allow connecting pipes with a diameter of 320 to 820 mm.

Example of parameters of external hydraulic centralizers

Small diameter pipes are connected with special devices that can be installed on welding tables, or used for welding directly on site:

• Chain vices and stops.
• Simple clamps in the form of pliers with a lock.
• Clamping centralizers (TsS) for welding pipes and fittings.

Typically, these centralizers are designed for pipes of the same diameter. However, if you need to regularly weld pipes of different diameters, you can make a homemade clamp or purchase a special device with independent clamps for each pipe. Manual clamps require preliminary joining of pipes for tacks, and the seam is welded.

A type of external centralizer is a device for connecting pipes made of polyurethane foam. This device allows you to connect plastic pipes by diffusion welding: the pipes are inserted into the device, heated up, and then connected by light hand pressure. At the same time, their even direction is preserved.

Spring loaded

A separate type of centering devices is a spring centralizer for a casing (string). These mechanisms are used when drilling oil and water wells, and other structures for underground or subsea use.

With the help of such centralizers, a uniform gap is provided between the pipe and the walls of the well so that the concrete solution is poured without the formation of voids and ruptures.

Spring centralizers consist of two shells and several steel strips, which rest on the borehole walls and prevent the pipe from swinging. Such mechanisms have only two welds, and the metal plates that perform the crimping function are made of solid steel plates.

Centering mechanisms cost

The cost of centralizers depends on their design type, purpose, overall dimensions and manufacturer, and ranges from several hundred to several hundred thousand rubles.

For work in a workshop, or periodic welding of household pipelines "on site", it is enough to buy an external device. The main thing is that these mechanisms can be adjusted within a certain range of sizes.

Chain mechanisms start at a price of 2800 rubles, link mechanisms - from 5000 rubles. Eccentric models will cost more - from 7,000 rubles.

The advantage of chain mechanisms is low price, simplicity of design, maintainability, the ability to align the ellipticity of the pipes being connected.

The installation of a hydraulic mechanism increases the cost of the equipment, but increases the quality of work and functionality. Below is the estimated cost of some types of pipe centralizers.

For professional work, the preferred centralizers of the German company Vietz and the company Clamp (USA).

In this article, we will talk about how and for what pipe centralizers are used. In addition, we will consider the design highlights of the most popular models from what is currently on the market. So what is a centralizer and what is it for?

An efficient method to make the weld even and tight

It is no secret that there are special devices adapted for the execution of a perfectly even cut of the cross-section of pipes. But, in addition, if the cut is made as evenly as possible, it will be virtually impossible to combine both pipes with cuts for high-quality welding.

As a result, the welded seam will be uneven and, as a result, the connection will not be tight enough. The solution to this problem can be an internal or external pipe centralizer.

Features of functioning

Both iron pipes and their PPU counterparts, before welding, must be leaned against each other as evenly as possible, so that there is no gap at the joint.

To make such a combination of slices with your own hands is practically unrealistic. Moreover, the alignment of the cuts becomes an order of magnitude more difficult with an increase in the diameter of the pipes. Based on this, during the assembly of sewer systems and other pipelines without the use of sewer fittings, special centralizers are used.

The device grasps two matching pipes and allows them to be connected to each other as accurately as possible, fixing them in this position. At the end, welding is performed with a guaranteed high seam quality. After that, the device is dismantled, and the pipeline can be used for its intended purpose.

Main varieties

After we have decided on what the centering equipment is used for, we will consider what specific types of devices are on sale.

All centralizers that are now possible to buy in the respective stores are divided into two main categories - indoor and outdoor.

• Outdoor devices are designated by the abbreviation ЦН and are intended for installation and use on the outside of pipes. Devices for that type, regardless of size, are simple to use, easy to install and create rapid and effective alignment. Outdoor devices are represented by a wide range of equipment (eccentric, link, hydraulic and other configurations).
• Internal centralizers are abbreviated to CV and are hydraulic installations... Devices of this type expand the edges of the pipes from the inside, moving their sections towards each other. The advantage of the equipment is the possibility of using it on pipes of different diameters.

Characteristics of individual modifications

At the end of how we examined the highlight of a non-specialized classification, we will consider the characteristics of individual modifications of centering devices.

• TsZN - external link centralizer is recommended for aligning the ends of pipes with a joint diameter of 50 mm to 2 meters.

It is fundamentally important: Operation of devices is allowed in a wide range of ambient temperatures from - 40 ° C to + 40 ° C. The device is structurally a polyhedron with lamellar links on articulated joints.

Tightening of the combined elements is carried out using a screw mechanism.

• TsZN-G - external hydroficated link centralizer is a modified version of the previous device. A significant difference of this modification from the previous one is the ease of operation and the absence of the need for significant physical effort. As a result, the process of aligning the elements to be welded is significantly accelerated without compromising the quality of the finished result. The device consists of articulated plate links, but hydraulics, not a screw mechanism, is used to set the links in motion. The permissible pipe diameter ranges from 720 to 2020 mm
• TSAN-G - hydraulic external arched centralizer is recommended for work with a cross-section diameter of 325-820 mm.

The device is a split structure consisting of hinged sections. The use of a device with such a design guarantees additional convenience when installed on the joint.

The device uses arcuate sections, which are compressed, adjusting the joint sections. The number of arcuate sections is determined by the pipe diameter.

Any of the sections used is equipped with special stops, which reliably fix the combined elements, providing at the same time an optimal level of quality and tightness of the joint. Specifically, the sections are equipped with hydraulic drives designed for a maximum developed force of up to 5 tf.

• TsNTs - external chain push-type centralizer is a hand-operated device designed to work with a cross-section diameter from 426 to 1420 mm.

Unlike link counterparts, chain installations are capable of providing greater effort when carrying out alignment. Devices of this type can be used both in the construction and in the repair of pipelines.

Fundamentally important: The chain structure is built using quick-release mechanisms, which has a positive effect on operating performance.

• TsNE - external eccentric centralizer is used to work with joints with a diameter of 89 to 426 mm.

The device has several gripping arcs driven by an eccentric clamp. The device can be used to work with pipes of different diameters by repositioning the eccentric axis or by using special spacers.

• TsV - an internal hydraulic centralizer is recommended for aligning the ends of swivel and non-swivel pipes.

The device, if necessary, not only aligns the joints, but also gives their cut the most correct round shape. The use of such devices makes it possible to build pipelines using continuous automatic welding.

• TsS - centralizer-clamp is used for working with pipes of small diameter.

This property and affordable price make the device the most popular among inexperienced and novice piping assemblers. (See also the article Butt Welding: Features.)

Conclusion

So, we examined what centralizers are like, what are their most popular varieties, and what are their instructions for use. Based on this information, it is possible to select the device that will match the zest of the work being carried out.

You can find more information you need by watching the video in this article.