The device of shut-off valves valves valves cranes. Pipeline accessories. Classification ─ species, types, varieties

Every person, regardless of where he lives, uses shutoff valves in his life. Any pipelines are always equipped with devices that make them safe.

Shut-off pipeline valves are designed so that a person can control the flow of the working medium moving through the pipeline. Moreover, it does not matter at all what exactly the working medium is - water, steam, gas, oil products, aggressive substances - without stop valves pipeline operation is not possible.

Types of valves

The materials most commonly used for production locking devices, are brass, bronze, steel and

The main characteristics of locking devices are:

diameter of the pipeline connected to it;
the value of excess pressure in the pipeline at a temperature of +20 degrees.

There are several types of devices related to valves:

flaps;
valves;
valves.

In order to determine the required type of reinforcement, you need to know in what conditions it will work. This is necessary because water pipelines, gas lines and systems designed for pumping aggressive substances are used completely different types equipment.

Types of stopcocks

Shut-off valves are widely used in the construction of any pipelines. They can be attached to pipes using one of two types of connections: flanged or coupling. It happens that branch pipes of cranes are welded to pipelines.

All cranes are divided into:

cork;
ball.

The cork faucet is shaped like a truncated cone. This is the oldest type of locking devices.
Currently, these devices are mainly used, the working environment of which is:

neutral and fuel gases;
phenol;
oil;
lubricating oils;
water.

The big disadvantages of these cranes are:

a large torque is required to control the crane, which requires the use of a gearbox;
in order to avoid sticking of the valve to the body, its constant maintenance is necessary;
the tightness of the tap depends on such a complex operation as rubbing it to the body;
there is a high probability of uneven wear of the device, which threatens the tightness of the system.

A ball valve is a device consisting of a body and a plug. The body is stationary, and the plug rotates, passing the working medium or blocking it.

Ball valves differ depending on the shape of the surface on:

conical;
spherical;
cylindrical.

In the manufacture of ball valves, a wide range of materials is used: titanium, cast iron, steel, zinc, ceramics, plastic.
Their main areas of application are:

for water supply and heating;
devices for connecting household appliances, where a periodic supply of water is necessary;
junctions and branches of pipelines;
industrial and food installations.

In addition, the reliability of the design of these locking devices, their resistance to temperature extremes and certain chemicals, allow these to be used where aggressive substances are the working medium.

Among the important characteristics of ball valves there is such an indicator as the method of installation. According to him, cranes can be:

coupling – used in pipelines of small diameter;
flanged - which are used in pipelines with a diameter of more than 50 mm, withstand rather large loads (can be used in industry);
choke - easily withstand repeated disassembly, therefore they are used mainly in industrial installations;
welded- fastened exclusively by welding, used in aggressive environments;
combined - combine several mounting options.

Gate valves

They are mainly used on pipelines of large diameter under the condition of low pressure of the working medium.

The shut-off body of the damper is a disk that is able to rotate around its own axis, located perpendicular or at an angle to the direction of movement of the working medium. The tightness requirements for dampers are much lower than those for taps.

The damper control can be:

with the help of an electric drive;
using a hydraulic drive.

As a rule, the damper body is made of cast iron, and the rotary disc is made of steel.

Impact resistance of cast iron chemical substances allows installation of dampers where alkalis, acids and corrosive effluents are pumped.

The dampers are cut into the pipeline using flange connection or welding. This type of shut-off valve requires virtually no maintenance.

The peculiarity of dampers is that they are able to pass the working medium containing solid particles.

gate valves

They are designed to block the flow of a non-aggressive working medium with high pressure and temperature. They are most often used in systems main pipelines related to housing and communal services, in water and gas supply, oil pipelines, energy facilities.

The locking element of the valve moves perpendicular to the direction of movement of the working medium.
W sliders, depending on the device of the working body, are divided into:

wedge - due to strong friction in the closed state, they can lose their tightness over time;
gate (parallel) - used for one-way flow of the working medium with not too high requirements for tightness (used on pipelines transporting wastewater, sludge and other media with mechanical impurities).

The most commonly used valves are equipped with an electric drive, which allows you to quickly shut off the flow.

The advantages of valves are:

small hydraulic resistance;
simplicity of design;
possibility of use in various conditions;
the ability to pass the flow in any direction;
high tightness;
high maintainability.

Shut-off valves

This is a widely used shut-off valve designed to completely shut off the flow of the working medium. Valve unable to regulate

A device such as a valve must always be in a fully open or fully closed state. It can be installed in any position.

The valve consists of a spool, which is located on a lowering spindle. When the valve is closed, the spool is lowered onto the seat and shuts off the flow. In this case, the shut-off element of the valve moves parallel to the flow, which prevents the occurrence of water hammer.
According to the type of sealing, valves are divided into:

stuffing box;
bellows;
diaphragm.

These devices are equipped with branch pipes, through which they are cut into the pipeline. If the valve is designed to operate under high pressure conditions, it has thick walls and is attached to the pipes by welding.

valves large sizes can flanges, and small ones - using coupling connections. The valves can be operated both manually and by means of an electric motor. There are options with remote control.

Cast iron socket valves are used when pumping air or water, the operating temperature of which does not exceed + 50 degrees. Brass socket valves are lightweight and have shown themselves well in high pressure systems. They are not afraid of pressure drops.

Cast iron valves with an electromagnetic drive are used on pipelines through which water or air moves with a temperature of not more than + 50 degrees.

Valves for aggressive environments

When working in aggressive environments, valves are most often used, due to the hermetic adjoining of the seat and spool and the almost complete absence of friction.

Brass performs very well in aggressive environments, so brass coupling valves are most often used in liquid media.
At high temperatures of the working environment, it is better to use bellows valves that can withstand temperatures up to +350 degrees. They are very reliable and guarantee high tightness in those connections where leakage of the working medium into the atmosphere is unacceptable.

In aggressive environments, the corrosion resistance of shut-off valves is very important, so porcelain flange valves are often used here.

Its body is completely made of porcelain, and the anti-corrosion coating is glaze applied to its surface.

They are found in complex and diaphragm valves with a protective coating of rubber.

Thus, knowing the features of valves, it is not so difficult to choose those products that are necessary for work in specific conditions.

In order to control the flow of various types of media (liquid, suspension, gas-liquid, gas and powder), their transportation and storage systems are equipped with special fittings - pipelines.

Classification, marking and standard requirements

Pipe fittings due to their ability to change the internal section of the pipeline allows you to effectively control flows various types avg. So, its use makes it possible to perform the following operations:

distribute the phases of the movement of working media;
reset the flow;
turn off the supply;
provide mixing of several streams;
adjust flow parameters;
carry out the distribution of the working environment.

The classification of reinforcement is based on its functionality. So, depending on this parameter, pipeline fittings can be of the following types.

Regulating type

With the help of such pipe fittings change the parameters of the flow of the working medium and, accordingly, its main characteristics. In this category, throttle and shut-off and control types are distinguished. With the help of fittings of the first type, which is often called reducing, it is possible to reduce the workload in the pipeline, which is done by increasing the hydraulic resistance in its flow zone. Shut-off and control pipeline valves are a set of devices with the help of which the regulation of the parameters of the working flow and its overlap are ensured.

locking type

Such pipeline fittings are used to hermetically shut off the flow of the working medium. If it is used to control the flow of the working medium into the control and measuring units, then it is called the control. There is also a drainage shut-off valve, due to which the working medium is discharged from pipelines or tanks.

Mixing and distribution type

Such pipeline fittings provide mixing of the working medium flows, as well as their distribution along the required directions of movement.

Protective

This pipe fitting is used to protect the elements of the system from the consequences caused by a change in the parameters of the flow of the working medium. Such changes can most often be the consequences of emergencies in the system. Valves of this type can also provide protection against reversal of the working flow.

phase separating

This is a pipeline fitting that separates the working medium into different phase states. For example, it can separate superheated steam from the working medium, retain condensate (steam trap), and also solve a number of other tasks.

Safety

This type of pipe fitting protects the system from a critical increase in pressure of the working medium.

Pipe fittings, according to the requirements of the State Standard R52720-2007, are characterized by two main parameters:

conditional pressure;
conditional pass.

The conditional pressure, denoted Ru or PN, characterizes the value of this parameter at which tanks or pipelines can be operated for a certain period of time, provided that the temperature of the working medium is +20 degrees Celsius. The classification of pipeline fittings and the nominal values of this parameter are stipulated by the State Standard 26349-84.

The values of the nominal diameter of the reinforcement, which is designated Du or DN, characterize the parameters of the elements that make up the pipelines. Permissible values of this parameter are stipulated by the State Standard 28338-89.

Other parameters of pipeline fittings

Pipeline fittings can also differ in their field of application. So, depending on this parameter, it is divided into the following categories:

general purpose (produced in series and can be used in most industries);
special purpose (its parameters are negotiated individually);
sanitary-technical (used to equip household equipment and produced on production lines; increased requirements are imposed on the aesthetics and ease of operation of fittings of this type);
for special operating conditions (designed to equip systems that are subject to increased requirements; as a rule, aggressive toxic media are transported through such systems);
for equipping shipbuilding and transport enterprises.

There are several ways of fastening pipeline fittings to tanks or pipeline systems. So, it can be attached using:

nipple (nipple);
flanges (flange);
couplings with internal thread(coupling);
fitting (fitting);
external thread(tsapkovaya);
threaded studs and nuts (coupling).

Pipe fittings, in addition, can be attached by welding. It is this method that ensures maximum tightness of the connection and does not require preliminary surface preparation. The big disadvantage of this method is that when using it, it is quite difficult to perform maintenance or repair of the elements of such a connection.

Pipe fittings are divided into several main types.

Rotary valve or faucet

The locking and regulating element in such valves performs reciprocating movements, moving parallel to the direction of movement of the working flow.

Disc (rotary) shutter (hermetic valve)

Such a valve, as its name implies, is made in the form of a disk, the axis of which is located at an angle or perpendicular to the direction of the working flow.

gate valve

The working element of such a device moves perpendicular to the direction of movement of the working flow.

Tap

The working element of such control or shut-off valves rotates around its axis, which can have a different position in relation to the direction of movement of the working flow.

Methods for the production, maintenance and repair of pipeline valves

Cases of pipeline fittings, which perform shut-off, protective and any other functions, can be made of the following materials:

various types of cast iron: grey, malleable and high-strength;
alloys based on titanium;
aluminum and its alloys;
steel, including alloyed and stainless;
glass;
polymeric materials, vinyl plastic;
copper-based alloys: bronze and brass;
ceramic materials, predominantly porcelain;
monel metal.

In order for pipeline fittings to successfully resist negative impact working environment, the inner surface of its elements is covered with various protective materials, the main of which are:

nairite or polymeric materials;
enamel coatings;
rubber;
lead.

Protective functions, in addition, are performed by sealing elements, for the manufacture of which the following materials can be used:

fluoroplastic compounds;
babbitt;
rubber;
copper-based alloys - brass and bronze;
sormite;
nitrated steel;
polymers;
ebonite;
stellite;
steel, mostly stainless;
Genuine Leather.

Pipe fittings for various purposes can be performed with a mechanical, remote or autonomous control drive.

In the event of failure of the elements of pipeline fittings, they are almost never repaired, but simply replaced with new ones. This approach is explained by the fact that the repair of such elements is not economically feasible, especially in situations where the entire pipeline is idle due to a breakdown. To significantly extend the service life of pipe fittings and minimize the risk of their sudden failure, it is enough to regularly carry out preventive measures and perform diagnostics.

The world of pipe fittings is huge and diverse, and at first glance it may seem chaotic and obscure.

But if you understand the principles of its classification proposed in the regulatory documents, it will become well structured and ordered. Classification is a very convenient and useful tool that gives each product its place and positioning it relative to other products, the tasks that it must solve, the fundamental device, the design features, the materials used in it, etc.

With regard to pipeline fittings, we can talk about two basic principles of classification ─ types and types of pipeline fittings.

Types of pipeline fittings

A kind of watershed between various types fittings is its functional purpose, depending on which it breaks up into several large segments: shut-off, reverse, safety, distributive-mixing, regulating, disconnecting.

It is one of the most common and sought after species. Thanks to its use, it is possible to completely block the flow of the working medium with one degree or another of tightness. Therefore, the tightness and tightness life are the basic indicators of the functionality and quality of shut-off pipeline valves.

With regard to shutoff valves, they speak of two states - “open” and “closed”. The intermediate position of the working body may not be provided.

The scope of its application is extremely wide and covers maritime transport, deep-sea vehicles, aviation and space technology, nuclear power and, of course, the blood vessels of the Russian economy - the main oil and gas pipelines.

A modern pipeline is a complex complex engineering structures, any failures in the operation of which, fraught with disruption of the normal course of the technological process, can lead to severe economic and environmental consequences.

The ubiquity of shut-off valves clearly illustrates the fact that by default the words “shut-off”, “shut-off” in combination with the type (more on types will be discussed below) valves are not used. For example, they don't say "gate valve", although gate valves are the most common type of valves.

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Reverse valves (it is not recommended to call them reverse-acting valves) are used to automatically prevent the reverse flow of the working medium.
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The task of safety fittings is to protect equipment from emergency overpressure or other parameters of the working medium by automatically dumping its excess. Perhaps one of the most striking examples of safety valves is safety valve installed on the steam boiler.

Safety valves make a significant contribution to ensuring the trouble-free operation and overall reliability of pipeline transport systems, industrial and power plants. It negates the consequences of the working environment parameters going beyond the permissible limits, for whatever reason they occur: equipment breakdown, maintenance personnel error, internal physical processes or external factors.
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With the help, the flow of the working medium is distributed in certain directions and mixed. However, a complete "division of labor" is possible. In this case, pipeline fittings intended only for distributing the flow are called distribution, and only for mixing it - mixing.
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A very important place in the general range of pipeline valves is occupied by control valves, which provide accurate and reliable regulation of the parameters of the working environment, without which it is impossible to organize economical and safe technological processes and form complex multicomponent production chains.
Control valves in their "pure" form and in combination with shut-off valves ensure the conditions for the normal functioning of the equipment and its good controllability at the most critical facilities, including nuclear power plants. Against the background of the complication of working conditions in the electric power industry (increase in the initial parameters of heat carriers, growth in the unit capacity of power plants), its relevance is only increasing.
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Shut-off valves (sometimes called protective valves) are designed to shut off the flow of the working medium when the specified, unforeseen by the technological process, value of its flow rate is exceeded due to a change in the pressure drop across the sensing element. The difference from safety pipeline valves is that the flow is not vented, but only a specific element is turned off.
Combined fittings include fittings that combine the functions of the above types. They have "speaking" names, from which it follows, the functions of which types of fittings they combine. For example, shut-off and regulating armature (it is not recommended to call lock-throttle) or lock-reverse fittings.
Non-return-shut-off And irrevocably controlled fittings perform the function of reverse fittings, in which forced closing or limitation of the stroke of the locking element can be carried out, and in irrevocably managing─ also limiting its course.

Types of pipeline fittings

There are even fewer main types of fittings than types - only four: valve, valve, butterfly valve. Belonging to each of them is determined by design features, expressed in the direction of movement of the locking or regulating element relative to the flow of the working medium.

The type of valve, in which the locking or regulating element moves perpendicular to the axis of the flow of the working medium, is called a gate valve.

A valve (it is better not to call it a valve due to the ambiguity and vagueness of this term) is a type of valve in which the locking or regulating element moves parallel to the axis of the flow of the working medium.
In the valve, the locking (regulating) element, made in the form of a body of rotation or part thereof, rotates around its own axis (this may be preceded by a reciprocating motion) arbitrarily located in relation to the direction of the flow of the working medium.
In a butterfly valve, a disc-shaped locking (regulating) element rotates around an axis located perpendicular or at an angle to the direction of the flow of the working medium.
Each of these types lends itself to more detailed structuring. So, valves, depending on the design of the seat and gate, are wedge and parallel, with a retractable or non-retractable stem (spindle).
Valves with a poppet-shaped shutter are called poppet valves, and those with a conical needle are called needle valves. In addition, valves can be single seat and double seat.
Cranes are divided into cone, cylindrical, ball.
Each of the listed types of pipeline fittings has its own advantages and disadvantages, and in accordance with them - more or less preferred areas of application.
So, a feature of gate valves is a significant construction height (the size from the horizontal axis of the flow section of the valve body to the upper end of the spindle, stem or actuator when the valve is fully opened), small construction length (the linear size of the valve between the outer end planes of its connecting parts to the pipeline or equipment) , low hydraulic resistance, high force on the valve drive, rather slow operation, and with contaminated liquids - wear of the seat surface. Gate valves do a much better job of shut-off valves than control valves.
Unlike gate valves, the most common type of pipeline fittings ─ valves ─ have a low structural height, large structural length, fast response, significant hydraulic resistance, and high tightness. Valves are included in the design of most regulators.
Cranes, like valves, have a low headroom and fast response. And as gate valves ─ small building length.
A butterfly valve (it is more correct to refrain from the name “flap”) has a small building height, building length, force on the shutter drive, hydraulic resistance and quick response.

Varieties of pipeline fittings

Just as in mathematics sets are divided into subsets, types of reinforcement can be structured into varieties.

● varieties by purpose and scope

The largest of these "subsets" are varieties by purpose and application.
Features of operation can be used as classification features - vacuum fittings, cryogenic fittings; or features of functioning, for example, shut-off valves (shut-off valves with a minimum response time). The basis for separation are also: installation site (receiving fittings ─ reverse reinforcement installed at the end of the pipeline in front of the pump) and the availability of additional options (heated fittings).
But the most compelling reason to separate the pipeline fittings on varieties ─ its purpose: control valves, anti-surge valves, pressure reducing valves, drain valves, test and bleed fittings, etc.
The areas of application of pipeline fittings cannot but impose special requirements on it. The fittings used in gas facilities must be airtight due to the high fire- and the explosiveness of the working medium in this case ─ gas.
Due to the rather high chemical aggressiveness of oil, pipeline fittings for the oil-producing and oil-refining industries must have increased corrosion resistance. Even more aggressive environment, including concentrated acids and alkalis, affects pipeline fittings used in the chemical industry.

● varieties of connection to the pipeline

On this basis, the fittings are divided into flanged, wafer, wafer (i.e. wafer installed between pipeline flanges). Coupling fittings are equipped with connecting pipes with internal thread. Fittings for welding - nozzles for welding to the pipeline. Connection fittings are also available for choke fittings.

● variations in design and shaping of the body

Based on the position of the nozzles, we can talk about straight fittings (connecting pipes are coaxial or mutually parallel) or corner fittings (the axes of the inlet and outlet pipes are located perpendicular or not parallel to each other). Fittings with offset axes of branch pipes are also produced.

If the cross-sectional area of the flow path less area openings of the inlet pipe ─ thisincomplete borefittings. If approximately equal to or greater than full bore fittings.
According to the method of manufacturing body parts, cast reinforcement is distinguished, cast-welded, litho-welded, stamping .

● varieties by type of seals

Valves in which the sealing of the stem, spindle or other movable element is relatively environment provided by a stuffing box seal, is called stuffing box fittings.

Valves in which a stuffing box seal is not used for sealing are called glandless valves. Bellows and membrane fittings fall into this category.

The alphabets of most languages of the world contain several dozen letters. But this did not stop them from accumulating hundreds of thousands of words, with the use of which millions of books were written. So it is with pipe fittings ─ its incredible variety consists of a relatively small number of classification units, measured in units, sometimes tens. And it did not appear by chance, but because of the need to answer a huge number of questions, to find an algorithm for solving a large number tasks.
Pipe fittings are subject to such a wide range of requirements that often the technical solutions that can be used to achieve them come into conflict with each other, and the emergence of a large number of different designs is one of the ways to overcome it. And the classification is The best way don't get lost in this variety.

Valves for pipelines - a range of structures installed on pipelines in order to control the transported medium by changing the actual area of the pipe flow section. Technical requirements and nomenclature of pipe fittings for industrial and household types are given in the regulatory document GOST No. 52720 "Pipe fittings".

This article presents the classification of pipeline fittings. We will consider its varieties, functional purpose, design features and study the marking of reinforcing products.

Article content

Classification of pipe fittings

According to the provisions of GOST, pipe fittings divided into groups based on the following factors:

functional purpose;
scope;
device control method;
method of connection with the pipeline;
sealing principle.

The main classification parameter is the functional purpose, according to which the following types of pipeline fittings are distinguished:

Shut-off valves are structures designed to completely shut off the flow of the medium circulating through the pipeline. Shut-off products, in turn, are divided into - drain valves (used to remove the transported medium from the pipeline) and control valves (shut off the flow and supply the working medium to instrumentation).
Control valves - used to adjust the throughput of the pipeline. It is divided into throttle - due to an increase in hydraulic flow resistance, and shut-off and control - combines the functions of two types of fittings, the most commonly used pipe fittings today.
Protective (cut-off) fittings - installation of cut-off fittings is carried out to protect the equipment connected to the pipeline and the main line itself in emergency situations. The valve closes and disconnects the failed part of the pipeline from the circulation ring, which makes it possible to carry out the required repair work. A type of protective fitting is, which prevents the possibility of a reverse flow of the circulating medium.
Safety fittings are structures that automatically relieve excess pressure in the system, which protects equipment and the pipeline from overloads.
Distribution fittings - installation is carried out in two adjacent pipelines if it is necessary to combine and mix their flows.
- structures used for either distributing the main into several channels. This group includes all kinds, bends, crosses, etc. The material for the manufacture of connecting fittings corresponds to the material of the pipeline (the production of both steel and polypropylene and polymer products has been established).

Depending on the scope of application, all pipeline fittings are divided into industrial and domestic. Household fittings are used for gas pipelines, water pipes and heating pipes. The class of industrial fittings, in turn, is divided into the following groups:

steam;
water;
oil;
chemical;
gas;
food.

A separate subgroup includes ship fittings used on military and civilian ships, which have an increased reliability class.

According to the method of control, pipeline valves are divided into two types - automatic and controlled. Controlled valves can have several types of actuators:

manual drive;
mechanical drive (electric, pneumatic, hydraulic or electromagnetic type);
remote drive - a control structure that is remote from the valve and is connected to it by means of a transmission (shaft, cable, gears or bearings)

Depending on the method of connection to the pipeline, pipe fittings can be:

flanged;
coupling;
tsapkovoy;
choke;
welding.

The last classification factor is valve sealing principle, according to which the structures are divided into:

stuffing box - at the junction of the fittings and the end part of the pipeline, glands made of asbestos, graphite, fluoroplastic or are placed;
bellows - instead of elastic materials, metal are used for sealing;
membrane - structures in which the membrane simultaneously performs a sealing and locking function;
hose - a pinched rubber hose is used as a sealing material.

Marking of pipeline fittings

Marking of pipeline fittings is carried out in accordance with the provisions of GOST No. 4666-75 "Pipeline fittings". The marking consists of alternating letters and numbers, example - 30s941nzh2, where:

30 - type of fittings (valve);
c - material of manufacture (carbon steel);
9 - drive type (electric);
41 - model number;
nzh - type of sealing material (stainless steel bellows seal);
2 - version.

You can find the decoding of each nomenclature component of the marking in the tables of TsKBA (Central Design Bureau of Valve Building).

The principle of operation of pipeline valves (video)

Types of pipeline fittings

Shut-off pipeline valves, the most common type of valve products, have several design options. Pipe fittings are divided into the following types:

shutter (disk shutter);
valve (valve);
tap.

In the construction of modern housing it is impossible to do without a device pipeline systems. Through the pipeline, water, gas, heat are supplied to the houses, and sewage flows are removed from the house. For quality work pipeline, control of the flow of water or gas flowing through it, branching or branch devices, pipe fittings are necessary. In order for your pipeline to function without problems, you need to understand the characteristics and purpose of these devices.

When installing pipelines, it is necessary to equip bends, bends, connections, regulate pressure, mix liquids or gases in a pipe, for this they use pipeline fittings - a special type of connecting and adjusting products for a pipeline.

The scope of reinforcement is different, therefore, there are such types:

shut-off pipeline valves - used when it is necessary to shut off the flow of liquid or gas in a pipe, for example, a valve or damper;
control valves - a subspecies of shut-off valves used to regulate (reduce or increase) the volume of liquid or gas flows in a pipe, for example, a valve or a tap;
safety valve - used to release excess steam or water in case the pressure in the pipe exceeds the allowable value. Serves to protect pipes, such devices include safety valves;
distribution and mixing fittings are branches, adapters, tees used to distribute flows through pipes and mixers for mixing flows, for example, plumbing mixers for a bathroom or kitchen;
condensate trap - designed to remove the resulting condensate and superheated steam.

Characteristics of pipeline fittings

On the modern market of products for pipelines, a huge number of domestic and foreign manufacturing companies are represented, as well as a range of products for pipelines that differ in functionality and characteristics. So if pipe fittings were needed during the construction of the pipeline, it will not be difficult to buy it.

In order for pipeline fittings to serve for a long time and reliably, it is necessary to take a responsible approach to its choice, to clarify the load with which your pipeline and its parts will work. The choice of fittings depends on the parameters that determine the technical characteristics of the devices.

The main parameters by which pipeline fittings are selected are:

nominal diameter of the pipe (marked DN), or, in other words, the inner diameter. This value determines the throughput of the pipe or fittings;
conditional pressure (marked PN) - an indicator of the maximum possible pressure at which the valve is operated in normal mode for a long time, is calculated at a temperature of 20⁰С;
working pressure - calculated at normal temperature conductive medium and denotes the highest excess pressure value at which the valve operates in a given mode for a long time;
design pressure - the predicted pressure expected when exposed to the minimum or maximum temperature;
temperature regime - the accepted operating temperature under which the fittings and the pipeline itself will be operated;
throughput of the pipeline - a characteristic that determines the cross section of the reinforcement;
shutter tightness level - affects the choice of material from which the fittings are made;
environmental parameters.

All of the above characteristics are important for the successful selection of pipeline fittings and the functioning of the pipeline. If known specifications pipeline, its purpose, expected loads, mode of use, then it will not be difficult to select the necessary pipeline fittings for it.

Types of pipeline fittings

Pipelines are built for transportation various substances– steam, water, oil, sewer, ventilation. Naturally, pipeline fittings for each type have their own.

The material from which the body parts are made can also be different. Accordingly, the fittings are:

steel pipeline fittings - the material is carbon and alloy steel;
fittings made of corrosion-resistant steel;
fittings made of gray, malleable or high-strength cast iron;
non-metallic fittings - based on polyvinyl chloride, vinyl plastic or other polymeric materials;
ceramic fittings;
glass armature.

The choice of material for pipeline fittings depends on the purpose and parameters of the use of the pipeline. So, for example, fittings made of gray and malleable cast iron cannot be used if they are subjected to sudden temperature changes or vibration effects.

Pipeline fittings also differ according to the field of application.

In industrial production, when installing water pipelines, heating systems, steam pipelines, pipe fittings for general construction purposes are used. Usually these are series-produced fittings (gate valves, shut-off valves, pressure valves, control valves, steam traps) of well-known companies, well-established. A variety of pipeline fittings are presented on the market, the price of which depends on the quality and fame of the manufacturer. For example, from foreign brands producing fittings, Zetkama, Polix, ARI-Armaturen are known.

Industrial fittings for use in special working conditions, used in pipelines that will be operated at low or high temperatures, with high pressure, using corrosive substances, toxic and radioactive liquids.

Plumbing fittings are used in the construction of household pipelines - supplying gas to household gas stove, plumbing and bathroom equipment with faucets, shower units. For these works, Ball Valves, valves, pressure regulators, check valves, filters.

There are also pipeline valves for special purposes, which are used in special conditions. technical requirements operation, for example, experimental facilities and is usually made to order.

If you have figured out the purpose of the pipeline, and, accordingly, the valves being purchased, think about the issue of connecting to the pipeline. Depending on the connection option, the following types are distinguished:

flanged pipeline fittings, for the connection of which flanges are used to the pipeline;
coupling fittings - connecting fittings with an internal thread, usually used with a nominal diameter of not more than 40 mm and when using a pipeline for neutral and non-combustible substances;
pin fittings - used under the same conditions as coupling fittings;
fitting fittings - fittings and fittings that are used to make turns, branches, transitions to a different diameter in pipelines;
welded fittings - used in the construction of steel pipelines and pipelines made of plastic materials and ceramics. Often the need to use this type of connection is caused by the danger of the conductive medium through the pipeline, and welded joints eliminate the possibility of leakage.

The choice of pipeline fittings is also influenced by the need to use regulation, it can be manual or automatic. Depending on this parameter, controlled and autonomous fittings are distinguished. Controlled valves are equipped with a manual drive, or, depending on the design, the drive can be mechanical, electric, hydraulic, electromagnetic.

In order for pipeline fittings to function for a long time and safely, when choosing, it is necessary to be guided by its functional purpose. Naturally, the buyer, when choosing fittings, looks not only at technical characteristics, but also at its cost, durability, ease and availability of use and maintenance. Among the pipe fittings on the market today, you can choose devices that meet all requirements.

Products for pipelines and pipeline fittings have now become the most demanded metal products, and with the growth of construction, there is every chance to increase their production and sales.