Dielectric coupling for a gas pipe. Dielectric insert, insulating insert. Purpose of a dielectric coupling for gas

Dielectric insert (insulating insert, dielectric insert for gas) -

This is a device that prevents the spread of so-called leakage currents (stray currents) through intra-apartment or intra-house gas pipelines. The dielectric insert not only eliminates possible heating and sparking of the liner in the event of accumulation of electrical potential, but also protects the electronics and internal electrical circuits of gas appliances and meters from failure due to the influence of harmful stray currents.
The main causes of leakage currents include the following:
- Damage to the general insulator at the entrance of the main pipe to apartment house or an insulator at the outlet of a gas distribution point (node). To protect against corrosion on main pipes specially served small electric potential. In the event of damage to the common insulator, this potential freely enters the intra-house and intra-apartment gas pipelines.
- Faulty or missing grounding electrical wiring in the house. Modern gas-consuming equipment has its own electrical circuits ( electronic components controls, electric ignition systems, lighting, etc.), and, in the absence electrical grounding, as well as in the event of a malfunction of the internal electrical circuits of gas-consuming equipment, these devices themselves become sources of stray currents.
- Unqualified connection electrical appliances and their illegal grounding by your neighbors (or the “craftsmen” they hired) on rigid gas pipes and risers.

Dielectric insert It is a permanent connection and is installed between the gas tap and the gas supply. The metal parts of the insert, fused into the dielectric, do not touch each other, which makes it impossible for leakage currents to pass through it (the insert). Insulating insert It has inner surface, completely covered with a dielectric, which eliminates contact of each of the metal parts of the insert with the gas passing inside the insulator.

Materials used:
- Metal parts: Sanitary brass LS59-1 according to GOST 15527;
- Electrical insulator: Polyamide according to GOST 14202-69 with fire resistance category PV-O according to GOST 28157-89.

Specifications:
- Nominal pressure PN 0.6 MPa, which is 200 times more than normal gas pressure in household gas networks (according to SNIP 2.04.08-87 and 3.05.02-88, gas pressure up to 0.03 atm is considered normal);
- Operating temperature: -60 to +100 degrees Celsius, which makes possible installation inserts and in unheated rooms;
- Pipe thread, 1/2" or 3/4";
- Inner diameter passage: 10.0 mm (for 1/2") and 14.5 mm (for 3/4")
- Electrical resistance at a voltage of 1000V is more than 5 MOhm;
- The insert does not require maintenance during operation.

Employees gas services In some regions, it is already mandatory to use a dielectric insert in intra-apartment and intra-house gas pipelines. In particular, its use is regulated by the order of MOSGAZ dated December 26, 2008. No. 01-21/425: "When replacing gas stoves and connecting them to flexible liner provide a dielectric insert."
“The spool is small, but expensive” - this expression is perfectly suited for the dielectric insert. The cost of this product is negligible even compared to the cost possible repairs electronic and electrical components modern gas equipment, not to mention the consequences of emergency situations such as fire or explosion.

The dielectric coupling for gas ensures safety in residential areas and saves people's lives.

Equipment running on natural gas is connected to electricity sources. To prevent an accident from occurring when electric current enters the gas pipeline network, a protective insert should be installed on gas appliances.

Purpose of a dielectric coupling for gas

For heating water heating system boilers and boilers are used. For cooking, the kitchen is equipped with stoves, ovens and hobs. The listed devices have a system of control sensors, electric ignition, and oven lighting. That's why gas type The device requires connection to an electrical network.

To prevent current from flowing through the gas pipe indoors, polyamide insulators - couplings - are used. For dielectric couplings for gas, yellow polyamide is used due to the low content of conductive impurities.

Dielectric insulating inserts will remain operational when current enters the gas network gas devices and gas meters.

How does a breakdown occur in the gas network?

Natural gas is supplied to homes and other premises via metal pipes, laid underground in urban environments or above its surface in the private sector. Metal corrodes when exposed to moisture. The application of a positive electrical potential helps reduce corrosion.

According to safety regulations, a dielectric coupling is installed on the pipe at the entrance to the house. This protects the gas riser indoors, provided that the coupling is installed correctly and is in good working order. But the solid grounding of a pipe in the basement of a house can break due to corrosion.

Next, in a house or apartment, suppose the stove is connected to the riser through a rubber hose with a metal braid. If suddenly the insulation of the electrical wire in the stove is broken, the current will flow through the braid of the hose. Depending on the current strength, the time for heating and breakdown of the hose will be short or long, but breakdown will definitely happen.

Sometimes the residents of the house arrange grounding on gas pipe.

A fire may occur if there is a gas leak in the apartment. Everything can be done without casualties, but with material losses. After such an event, the question of why a dielectric coupling for gas is needed will no longer be hypothetical for residents.

How the coupling works

Gas network parts are produced in several types depending on the type of fastening: “fitting - fitting”, “nut - fitting”. The product is one-piece, non-separable, and therefore safe to use. Any excess connection is a source of gas leakage.

High-quality couplings are made of brass, the thickness of the tube is at least 4.5 millimeters. The insulating part is made of yellow polyamide, which contains a “flame retardant”.

Selection of liner and coupling

It is better to choose a bellows liner coated with a yellow insulator. It is easier for housewives to wash such eyeliner from dust and kitchen soot. At the same time, the insulator will protect against the flow of current when touching the exposed terminals of live devices or the conductive body of the device.

Of course, you could supply an inexpensive rubber hose. But rubber tends to age, lose elasticity, and microcracks appear on the rubber hose - places of gas leakage.

Dielectric couplings for gas will protect against current flow through any hose. These parts are tested for breakdown with a current frequency of 50 Hertz and a voltage of 3.75 kV for 6 seconds or more. When applying voltage one kilovolt electrical resistance is 5 megaohms. The inserts can withstand temperature differences from -60 to +100 degrees. Insulator manufacturers guarantee a service life of at least 20 years.

By installing a dielectric coupling for gas, leaving home on business or taking a bath, the reader will be confident in the safety of his home, loved ones and neighbors. Dielectric insulator - protection against burning through the liner, subsequent gas leakage and inevitable explosion.

Dielectric insert(or - permanent connection that prevents the spread of leakage currents. The dielectric insert also protects electronic components(for example, control units) and electrical circuits (for example, electric ignition system, lighting) of gas-consuming equipment from the harmful effects of stray currents. The insert is installed between the gas tap and the gas supply. Of course, stray currents can also damage gas meter. And, importantly, the insulating insert eliminates possible heating and even sparking of the metal gas line as a result of the accumulation of electrical potential on it.
There are several reasons for the occurrence of stray currents, or leakage currents. The main ones are:
-Damage to the insulator on the gas main. On steel pipes main gas pipelines, to prevent corrosion, a small electric potential is specially supplied, which must be extinguished at the entrance to the apartment building or at the exit from the gas distribution unit in the immediate vicinity of the outlet to individual home. For these purposes, a special main dielectric insert is used. In case of its destruction or absence, the electrical potential freely penetrates into the intra-house and intra-apartment gas pipelines.
-Lack of electrical grounding, faulty wiring and local electrical circuits. Modern gas consuming appliances ( gas boilers and water heaters, stoves, ovens etc.) are often crammed with electronics and local electrical circuits. These include electronic control modules, electric ignition, timers, lighting systems, etc. In the absence of the necessary electrical grounding, as well as in the event of contact with electricity metal case equipment due to a malfunction of local electrical circuits (the so-called ground fault), such equipment itself becomes a source of harmful currents.
-Illegal grounding electrical appliances on gas steel pipes. Often your neighbors, who have entrusted the work of connecting certain electrical appliances to “craftsmen,” are blissfully unaware of the fact that their (neighboring) electrical appliances are grounded to a gas pipe.

SPECIFICATIONS:

Connection dimensions insulating inserts: 1/2", 3/4";
Execution option: fitting-fitting;
Material metal parts: brass CW614N according to EN12165, analogue of sanitary brass LS59-1 according to GOST 15527;
Dielectric: Polyamide according to GOST 14202-69 with fire resistance category PV-0 according to GOST 28157-89;
Nominal pressure PN=6 Bar (or about 6 atm). For reference: according to SNIP 2.04.08-87, in intra-house and intra-apartment gas pipelines, gas pressure up to 0.03 atm is considered normal;
A conversion table for pressure units is available on our website.
Electrical resistance: more than 5 MOhm at U=1000V;
Operating temperature range: from -60 to +100 degrees. Celsius.

The use of an insulating insert is regulated by MOSGAZ Letter No. 01-21/425 dated December 26, 2008: “...When connecting gas stoves to a flexible connection, provide a dielectric insert.”

Dielectric insert:

To wander electricity, formed in the gas pipeline, did not damage the gas appliances installed in our houses and apartments; special dielectric inserts or couplings for gas are used, which are installed between the gas pipe. What is “stray current”, why does it occur, why is it dangerous and how to protect gas appliances from it?

Stray current appears in the ground when power lines malfunction; it can occur due to an electrical accident. railway or tram tracks, in case of emergency condition of power lines.

Difference between resistivity land and steel structures gas mains is so large that the current does not go into the ground, but into these very metal constructions. Due to the fact that both household and main pipelines made of metal, the stray current goes straight into our gas system.

Stray current suddenly appears when incorrect installation, boiler or column connected to electricity. It turns out that stray current is a real serious problem for the safety of not only one individual apartment, but also an entire multi-story building.

Insulating barrel and squeegee

1. As a result of exposure to stray current, your gas appliances may lose their functionality or become sources of stray current themselves.

2. If a stray current occurs in the pipeline, then during a thunderstorm or emergency situation On a power line, a person can be seriously injured with the most severe consequences.

3. A spark may appear in the gas pipeline as a result of stray current, causing real threat fire, and in case of explosion gas mixture Not only one apartment, but an entire multi-storey building can be blown up.

A dielectric insert is far from being someone’s whim; it is an obligation to install for those who have in their house or apartment gas equipment connected to electricity.

That is why, when laying a gas distribution pipe, the contractor must be guided by a set of rules (SP 42-101-2003, paragraph 6.4), which talks about the mandatory installation of dielectrics, even if the pipeline is not made of metal, but, say, polyethylene.

Types of dielectric inserts for gas

Dielectric inserts for gas are manufactured by our industry in several versions. They are usually divided into two main types:

1) insulating couplings, barrels, pipes, taps;
2) dielectric bushings.

Dielectric coupling for gas

Dielectric couplings are conventionally divided into 3 main types, differing from each other only by the thread diameter:

— ⌀ 15 mm or 1/2′;
— ⌀ 20 mm or 3/4′;
— ⌀ 25 mm or 1′.

This division by thread size allows you to install couplings on any pipeline system with absolute accuracy, since thread diameters less than 1/2′ and more than 1 1/4′ are not used in our gas pipeline system. Dielectric couplings are not just desirable, but mandatory when installing hoses for gas appliances.

Tap with isolating coupling

1. Barrel (“nozzle-nozzle”): both ends have external threads.
2. Barrel (“nut-fitting”): one end has an internal thread, the other - an external thread.
3. Coupling (“nut-nut”): both sides with internal thread.

Unlike a coupling, a bushing is a liner that does not allow electrical current to pass through. Installed between the gas pipe and the supply line. The bushings differ from each other only in their size, that is, the diameter of the liner. It is customary to use bushings with a diameter of 8 to 27 mm.

Dielectric sleeve for gas

- are made from non-flammable material, a polyamide with very high level resistance up to 5 million ohms;

— have approximately the same strength indicator: the working pressure of both couplings and bushings is 6 atmospheres, and the maximum withstand pressure is about 493 atmospheres.

How to properly install the dielectric insert

Both the coupling and the bushing are installed between the gas pipe and the hose. If you install the dielectric yourself, pay attention to the order and sequence of your manipulations.

1. Shut off the gas in the pipe through which it is supplied to the gas appliance.
2. In order for the gas in the supply to burn out to “zero”, you need to leave the burners on gas appliances open.
3. Prepare two adjustable wrenches.
4. Use the first wrench to hold the tap on the pipe, and with the second, unscrew the nut of the flexible hose (it is necessary to have two adjustable wrenches to prevent gas from gushing out).
5. Screw the hose nut, through which gas flows from the pipe to the gas appliance, to the end of the coupling.
6. Check your work for leaks by applying soapy water to the joint with a shaving brush.

Open the valve, make sure there are no bubbles at the joints, if there are none, then your job is done correctly.

Correct installation of the dielectric insert for gas

Manufacturers and prices

To feel the difference in price, let’s compare just a few dielectrics of domestic and imported production. The trademark “Tuboflex” (a Turkish brand that was transferred to the Russian campaign) is now in good demand:

— bushing, connection for gas (thread-thread) “TuboFlex”, price 159 rubles;
— bushing, nut-fitting connection, “TuboFlex” ⌀ 20 mm, price 146 rubles;
— coupling “Lavita” HP 20mm, thread ⌀ 3/4′, price 250 rubles;
— detachable coupling “Viega Sanpres 2267-22X1”, price 3075 rubles;
— detachable coupling “Viega G3 Sanpres 2267-20X1”, price 4033 rubles.

Today we looked at dielectric inserts (couplings, bushings), application, why they are needed, their characteristics and prices. We looked at the types of dielectrics and the differences between insulating threaded connections. Let's watch the video.

1 area of ​​use

1.1. Insulating inserts (hereinafter referred to as inserts) for intra-apartment gas pipelines are designed to prevent leakage currents from flowing through the gas pipeline when a neutralized electrified gas occurs on the housing gas appliance electric potential.

1.2. The inserts are designed for installation on gas pipelines transporting natural gas according to GOST 5542-87 and liquefied gas according to GOST 20448-90 and GOST R 52087-2003.

1.3. Application of the insulating insert provided for by SP 42-101-2003 ( General provisions on the design and construction of gas distribution systems made of metal and polyethylene pipes).

2.Specifications

2.1. Inserts are manufactured in accordance with TU 4859-008-96428154-2009.

2.2. The production of inserts is carried out in a mold on a thermoplastic machine using the screw extrusion method. polymer material as an electrical insulator and metal threaded pipes.

2.3. Operating pressure inserts: 0.6 MPa.

2.4. Breaking insertion pressure. 1.2 MPa, no less.

2.5. Operating temperature: from -20"C to +80"C.

2.7. Electrical strength. Inserts withstand test voltage 37508 alternating current frequency 50Hz, applied to metal pipes. Electrical breakdown is not allowed. Electrical strength is ensured for 1 minute, no less. The leakage current does not exceed 5.0 mA.

2.8. Electrical resistivity Inserts DC voltage 10008 is 5.0 MOhm, no less.

2.9. Resistance category of polymer electrical insulating material is PV-0 (according to GOST 28157-89). Electrical insulating material has a distinctive color yellow color(according to GOST 14202-69, group 4, flammable gases (including liquefied gases)) At the request of the consumer, the use of black material is allowed.

2.10. Marking. Markings are applied to the surface of the electrical insulating material, including the indication trademark, 1/DI-GAS, and nominal diameter, for example, DN20.

2.11. Nominal diameters of inserts (threaded pipes): DN15 (1/2"), DN20 (3/4").

2.12. Inner diameter of the passage. DN15 10.0 mm, DN20: 15.0 mm.

2.13. Connection type: cylindrical pipe thread, external/external thread.

3. Transportation and storage

3.1. Inserts can be transported various types transport subject to protection from mechanical damage, exposure to precipitation in accordance with the rules of transportation on this type of transport.

3.2. Inserts are stored in closed and other premises with natural ventilation without artificially regulated climatic conditions, where fluctuations in air temperature and humidity are significantly less than at outdoors(for example, stone, concrete, metal storage facilities with thermal insulation and other storage facilities) located in any macroscopic areas, including temperate and cold climates.

4. Installation and operating instructions

4.1. Installation of the Insert must be carried out by specialists who have been trained and have a license to connect gas equipment.

4.2. It is prohibited to dismantle/install the Insert without first closing the gas supply valve.

4.3. The inserts do not require verification or maintenance during operation.

4.4 The insert is used in conjunction with a flexible metal connection to electrified gas appliances and is installed on the intra-apartment gas pipeline on the outlet after the tap.

5. Manufacturer's warranty

5.1. The manufacturer guarantees that the inserts comply with the requirements of TU 4859-008-96428154-2009 provided that the consumer complies with the conditions of transportation, storage, installation and operation.

5.2. Guarantee period operation - 36 months from the date of commissioning of the Insertion, but not more than 60 months from the date of manufacture, subject to compliance with the rules of storage, installation and operation.

5.3. The service life of the insert is 20 years. Does not require maintenance during operation.

5.4. The manufacturer reserves the right to make changes to the design of the Insert without notifying the consumer.