Electrically insulating flange connections on gas pipelines. Insulating flange connections for gas pipelines. Packing Certificate

Insulating flange connection IFS of two flanges "economy" series (without down conductors, without painting)

Diameter
	10 atm	16 atm	25 atm
IFS-20	800	1100	1400
IFS-25	850	1200	1550
IFS-32	1000	1400	1800
IFS-40	1100	1500	1900
IFS-50	1200	1700	2000
IFS-65	1300	1800	2300
IFS-80	1600	2200	2800
IFS-100	2200	2600	3000
IFS-150	3800	3900	4500
IFS-200	5900	6100	6500
IFS-250	8500	8800	9400
IFS-300	10300	10500	11200
IFS-350	15000	17200	20000
IFS-400	22000	22100	on request
IFS-500	29000	39500	on request
IFS-600	41000	54800	on request
IFS-700	on request	on request	on request

Insulating flange connection IFS of three flanges "standard" series (without down conductors, without painting)

Diameter	Pressure / Cost (rub. with VAT) price from February 1, 2016
	10 atm	16 atm	25 atm
IFS-20	1320	1320	1380
IFS-25	1320	1320	1380
IFS-32	1380	1380	1500
IFS-40	1680	1680	1740
IFS-50	2040	2040	2100
IFS-65	2160	2160	2200
IFS-80	2700	2700	2820
IFS-100	3360	3360	3720
IFS-150	5280	5280	5640
IFS-200	7500	7500	8100
IFS-250	9600	10200	10680
IFS-300	13200	13440	13920
IFS-350	on request	20780	on request
IFS-400	on request	33000	on request
IFS-500	on request	55800	on request
IFS-600	on request	67200	on request
IFS-700	on request	85800	on request

Insulating flange connection IFS of three flanges "premium" series (with down conductors, with painting)

Diameter	Pressure / Cost (rub. with VAT) price from October 20, 2015
	10 atm	16 atm	25 atm
IFS-20, IFS-25	1600	1600	1700
IFS-32	1650	1650	1800
IFS-40	2100	2100	2250
IFS-50	2500	2500	2600
IFS-65	2600	2600	2750
IFS-80	3250	3250	3450
IFS-100	4100	4100	4500
IFS-150	6400	6400	6800
IFS-200	9000	9000	9800
IFS-250	11550	12300	12900
IFS-300	16000	16500	16900
IFS-350	on request	25000	on request
IFS-400	on request	40000	on request
IFS-500	on request	67000	on request
IFS-600	on request	67500	on request
IFS-700	on request	103000	on request

insulating flanged compound (IFS) is an integral component of pipelines of oil and gas transportation systems, oil products and other flammable substances with a high flammability and explosion hazard.

Installation of the IFS, which are not subject to corrosion when in contact with transported liquids and gases, provides surface pipelines with a multiple reduction in the likelihood of current discharges (stray currents, currents caused by electrochemical corrosion of the pipeline material and other causes) and their protection against electrochemical corrosion.

Application flange connections IFS relevant in the following cases:

• On various branches of gas and oil pipelines from the main highway;
• When laying a pipeline in close proximity to objects that are a potential source of stray currents;
• To disconnect the pipeline from any uninsulated earthed structure or underground structure;
• When to perform pipe flange connection made of various alloys;
• At gas distribution stations and points.

Design of flange connections IFS

The design of IFS flange connections is a tight hermetic joint of two or three collar flanges with a protective sleeve made of a material with dielectric properties installed between them. Vinyl plastic, fluoroplastic, or paronite PON-B. For the invariance of electrical insulating properties under the influence of factors external environment(moisture and temperature effects), a detachable sleeve IFS compounds covered with a layer of bakelite varnish. This coating has dielectric properties and at the same time prevents the sleeve material from absorbing moisture.

The connection of two flanges of pipelines and a bushing between them is carried out using polyethylene or fluoroplastic tightening studs. In addition, the design insulating flange connection (IFS) provides threaded sockets for screws, with the help of which special equipment is attached to the flanges, which makes it possible to measure the electrical resistance between structural elements.

Insulating flange connections: prices and types

The insulating materials presented in the price list of our company flange connections of pipelines have different designs and are designed for different operating conditions.

We can choose flange connections of gas pipelines based on the following criteria, which directly determine the price of the product:

• dimensions of flange connections (diameters of pipelines) - from 25 to 700 mm;
• the value of the working pressure in the pipeline (from 10 to 25 atmospheres);
• number of flanges (two or three);
• the presence of a current collector (with or without it);
• climatic version according to GOST 15150-69.

If you need insulating compounds (IFS), buy them with a guarantee by itself favorable price You are offered by PKF Spetskomplektpribor LLC. The entire list of products supplied by us (including insulating flange joints of steel structures) is certified, their high quality is confirmed by state certificates and permits from the FTIAN.

We produce insulating flange connections such as: IFS-32, IFS-25, IFS-40, IFS-65, IFS-50, IFS 100, IFS-150, IFS-80, IFS 200, IFS 300, IFS 250, IFS 350 , IFS 400, IFS 500, IFS 600, IFS 700. On request, we manufacture a flange insulating connection from steel 09G2S and from steel 12X18H10T. If you want to make the best choice of this and other gas equipment, we strongly recommend that you take advantage of the advice and qualified assistance of our specialists through the online consultation form.

The topic of insulating flange connections is relevant today for many enterprises.

The insulating flange connection is one of the elements of the pipeline system and is designed to protect against the effects of electrochemical corrosion.

Because a large number of pipelines are laid underground, then the problem of electrochemical impact on the pipeline is acute for those who operate these systems.
Electrochemical corrosion of pipelines is a consequence of the influence of electric currents of the earth, or, as they are also called, stray currents. Electric currents penetrate pipes that have insulation defects. Entering the pipeline electricity forms a cathodic zone at the point of penetration, which is not dangerous for the system, but at the point of current exit a dangerous anode zone is formed, which leads to the destruction of the metal as a result of the current. The consequences of such an impact may be: destruction of the metal, formation of cracks, which in turn leads to leakage of gas, water, oil, etc. Such changes in the system can lead to emergency situations.
Ensuring electrochemical protection is provided for by official documents, namely: Departmental building codes “Construction of main and field pipelines. Means and installations of electrochemical protection” (VSN - 009-88), GOST R 51164-98 “Steel main pipelines. General requirements for corrosion protection”, etc.
Insulating joints are used on pipelines to provide electrochemical protection.

Insulating connection (IC). IP classification
Formally, insulating compounds can be classified as follows (Fig. 1):

Currently, the most common IC design is the insulating detachable flange connection.

Insulating flange connection
An insulating flange connection is a structure consisting of flanges, insulating rings (gaskets) between them, insulating bushings that are installed in the mounting holes, as well as studs, nuts, washers.

Purpose and conditions of use
IFS is used as one of the means of protection against electrochemical corrosion of underwater and underground (ground) pipelines.
An insulating flange connection is installed in the following cases:
on pipelines near objects that can be sources of stray currents (tram depots, power substations, repair bases, etc.);
on branch pipelines from the main line;
for electrical disconnection of an insulated pipeline from uninsulated grounded structures (gas pumping, oil pumping, water pumping stations, field communications, pipelines, art wells, tanks, etc.);
when connecting pipelines made of various metals;
for electrical separation of pipelines from explosive underground structures of enterprises;
at the outlet of the pipeline from the territory of the supplier and the entrance to the territory of the consumer;
at the input of the heating network to objects that can be sources of stray currents;
on the above-ground vertical sections of inputs and outputs of hydraulic distribution stations (gas distribution points) and GDS (gas distribution stations);
for electrical disconnection of pipelines from underground structures of enterprises where protection is not provided or prohibited due to explosion hazard.

Designs of insulating flange connections
At the moment, we are aware of one nationwide regulatory and technical document regulating the design and dimensions of IFS - GOST 25660-83 "Insulating flanges for underwater pipelines at Ru 10 MPa", but each manufacturer in the manufacture of IFS is guided by the requirements of the customer and according to these requirements designs connection.
Considering design features insulating flange connection, the following types can be formally distinguished:
IFS according to GOST25660-83;
IFS, consisting of three flanges;
IFS manufactured by Gazavtomat LLC (with the use of butt-welded flanges of 2 and 3 versions).
Recommendations for the manufacture of IFS, which are worth paying attention to, are spelled out in the "Rules for the Design and Safe Operation of Process Pipelines" (PB No. 003.585-03 dated 10.06.2003).
Consider various designs of IFS (Fig. 2,3,4).

IFS according to GOST 25660-83
The assembled IFS according to GOST 25660-83 is used for electrochemical protection against corrosion of underwater, underground and surface pipelines at a pressure of 10.0 MPa (100 kgf/cm2) and an ambient temperature not higher than 80 0C.
Technical requirements to flanges are set out in GOST 12816-80 "Flanges of fittings, fittings and pipelines for Ru from 0.1 to 20.0 MPa".
The ring for this connection can be made of textolite (according to GOST 5-78), fluoroplast (according to GOST 10007-80) or paronite (GOST 481-80). This is due to the fact that these types of materials are quite moisture resistant and do not allow the external environment to adversely affect the connection elements.
According to GOST 25660-83, gasket and bushing materials must have the following properties:
breaking load - not less than 260 MPa;
electrical resistance - not less than 10 kOhm;
water absorption - no more than 0.01%.
Also, to ensure electrochemical insulation, it is necessary to cover the surfaces of the flanges that come into contact with the gasket with a special electrically protective material, polytetrafluoroethylene or a composition based on fluoroplast grade F 30 LN-E. Coating thickness 0.2 (±0.05) mm. The coating must be of equal thickness and glossy, and also must not have delaminations or swellings, porosity, cracks and chips.

IFS consisting of three flanges
FIS data are widely used in gas industry.
In their design (Fig. 3), in addition to two main flanges welded to the ends of the gas pipeline, there is a third flange, the thickness of which depends on the diameter of the gas pipeline and is in the range of 16-20 mm. To electrically isolate the flanges from each other, paronite gaskets are installed between them. Gaskets are coated with electrically insulating bakelite varnish in order to protect them from moisture saturation. Electrically insulating gaskets can also be made of vinyl plastic or fluoroplastic.
Tightening studs are enclosed in split sleeves made of fluoroplastic, insulating gaskets made of paronite coated with bakelite varnish are also provided between the washers and flanges. Along the perimeter of the flanges there are threaded sockets into which screws are screwed, used to check the electrical resistance between each main flange and the intermediate one.
These IFS are installed on Du from 20 mm. The design mainly uses flanges according to GOST 12820-80.
The disadvantage of such a connection can be considered that it can withstand pressure only up to 2.5 MPa.
IFS, as a rule, are mounted on the above-ground vertical sections of inputs and outputs of hydraulic fracturing and gas distributing stations. To control the serviceability and repair of the IFS, they must be installed after the shut-off valves along the gas flow at a height of no more than 2.2 m.
For these IFSs, the resistance (assembly) in the wet state must be at least 1000 ohms.

IFS manufactured by Gazavtomat LLC
This type of IFS was developed by Gazavtomat LLC and complies with the requirements of all necessary regulatory and technical documents.
The main difference of this insulating flange connection is that its design uses two flanges according to GOST 12821-80 "Butt-welded steel flanges for Ru from 0.1 to 20.0 MPa": 2nd version (with a ledge) and 3 -th version (with a cavity) - with minor design modifications (the size of the protrusion is reduced and the size of the cavity is increased). This is due to the need to provide greater electrical insulation and tightness of the system. These IFS can be used for pipelines operating at nominal pressure up to 6.3 MPa and at temperatures up to 300 °C. I would like to note that the use of flanges of the 2nd and 3rd versions according to GOST 12821-80 is not accidental. In accordance with building codes and regulations (SNiP 2.05.06.85), as well as safety rules (PB) dated 10.06.2003 No. 03-585-03, it is recommended to use flanges of these designs for IFS, which ensures a high level of technological safety. pipelines.
The whole structure reliably isolates two sections of the pipeline from each other, interconnected by an insulating flange connection.
An insulating gasket is installed between the flanges, insulating bushings are installed in the fastener holes, insulating gaskets are provided between the nut washers and flanges. The material of the gasket, insulating bushings and washers must satisfy the tightness conditions of the flange connection at the operating parameters of the pipeline (pressure, temperature).
As the insulating material to be laid, paronite is used, which is pre-dried, which makes it possible to increase the electrical resistance. To protect the gaskets from moisture saturation after manufacturing, they are carefully covered with electrically insulating bakelite varnish (BT-99).

IFS assembly
The manufacture and assembly of the IFS is carried out in the factory.
When assembling insulating flange joints, a clear sequence must be observed:
1) before assembly, the sealing surfaces of the flanges are coated with insulating varnish or special spraying (IFS according to GOST 25660-83);
2) IFS fasteners are isolated from the flanges with bushings (GOST 25660-83) or insulating gaskets;
3) in order to avoid distortion, the flanges are connected by sequential tightening of diametrically opposite studs;
4) before and after assembly, the ends of the insulating gaskets and washers, as well as the inner surface of pipes and flanges, are coated with insulating varnish, and the flanges are dried at temperatures up to 200 °C.

IFS tests
In addition to the fact that IFS are subjected to tests, which are provided for by the documentation developed by the manufacturer of IFS, there are general test requirements for them, which are set out in the "Rules for the Design and Safe Operation of Process Pipelines". According to this document, the assembled FSI must pass electrical and hydraulic tests.
The assembled insulating flange connection is tested in a dry room with a megger at a voltage of 1000 V.
During electrical tests, insulating flanges are checked both in a wet and dry state with a special device - a megohmmeter. These tests must be carried out in the following sequence:
between flanges;
between each flange and each stud.
In order to carry out the so-called wet tests, it is necessary to douse the IFS with water and hold it for one hour.
Dry insulation resistance requirements:
between flanges - not less than 0.2 MΩ;
between each flange and each stud - at least 1 MΩ.
Wet insulation resistance requirements:
between flanges - not less than 1000 Ohm;
between the flange and the stud - at least 5000 Ohm.
For hydraulic tests for the strength and tightness of the connection, the method of pressure testing with water on a special stand is used. Crimping is done with a hydraulic hand pump.
Unfortunately, hydraulic testing leads to a rise in the cost of products several times, which, most often, does not suit the client. In this case, it is possible, in agreement with the customer, not to carry out these tests, since they will still be carried out at the installation site during the verification of the entire system.
An act must be drawn up for electrical and hydraulic tests.

Connections are designed for operation in the range from residual pressure (vacuum) of 0.001 MPa to overpressure of media not higher than 25.0 MPa, minimum working medium temperature not lower than -60 ºС and maximum working medium temperature not higher than + 260 ºС.

The scope of the IFS is pipelines in the chemical, petrochemical, oil, oil refining, gas and other related industries that transport gaseous, vaporous and liquid media.

In terms of resistance to the influence of climatic factors of the external environment, the devices must comply with UHL versions, placement category 1 in accordance with GOST 15150.

Connections must be designed for installation in geographic areas with seismic activity up to 8 points inclusive according to the 12-point scale adopted in the Russian Federation in accordance with SNiP II-7.

Connections should refer to products for a specific purpose (IKN), type 1, recoverable, in accordance with GOST 27.003.

Design and manufacture of IFS

The composition of the insulating flange connection includes two or three flanges, between which seals-insulators are embedded. The flanges are connected to each other with studs and bolts. The studs are separated from the flanges by PTFE bushings or, alternatively, by heat shrink tubing of the same material. Nuts and washers are isolated from the flanges with fiberglass in accordance with GOST 12652-74. For the possibility of connecting to the system of electrical measuring devices, there are screw connections in the connections. Through it, you can even connect a spark charger.

IFS design with two flanges

• 1 - flange;
• 2 - insulating gasket (PTFE);
• 3 - pipe;
• 4 - nut;
• 5 - hairpin;
• 6 - metal washer;
• 7 - insulating washer (glass fiber);
• 8 - insulating sleeve (PTFE). IFS design with an intermediate flange

• 1, 2 - flanges;
• 3 - pipe,
• 4 - insulating gaskets (PTFE);
• 5 - hairpin;
• 6 - nut;
• 7 - metal washer,
• 8 - insulating washer (glass fiber);
• 9 - insulating sleeve (PTFE).

  The IFS corresponds to the UHL climatic version with placement category 1 according to GOST 15150.

  IFS must comply with the requirements of GOST 25660, GOST 12.2.003, GOST 12.2.049, the requirements of these specifications and set design documentation approved in the prescribed manner, as well as the requirements of the regulatory and technical documentation of Rostekhnadzor.

Insulating flange connections can carry out their functions from any position. Their connection parameters comply with the requirements established by GOST 12815, 12820 and 12821. The connections are parallel to the sealing surface, deviating from it by only 0.2 millimeters for every 100 millimeters of length. The design of the IFS allows you to avoid accidental loosening of the fastening as assembly units, and nodes. You will not find sharp edges or burrs on the parts. There may be only small dents, sludge inclusions or other small defects on surfaces that have not yet been treated. However, the work environment is not allowed to pass through the junction points. All used pressures, both test and working, comply with the requirements of GOST 356.

Flanged connections are able to withstand vibrations of 2 mm/s generated by external sources near the installation site. They are not afraid of the details and the impact of the external environment.

If even more stringent requirements are not indicated in the drawings, then the maximum dimensional deviations should be calculated using the following formulas:

For mechanical surfaces Machinable: holes H14, shafts H14 ( plate)

For non-machined surfaces, as well as at the joints between processed and untreated is calculated based on the table below.

The mass of the flange connection has a minimum error. From the figure indicated in the drawings in terms of dimensions, the final value differs by 10% up or down. Threaded connections are made in accordance with GOST 24705, GOST 9150, GOST 16093. As for the thread accuracy class, according to GOST 16093 it will be no lower than coarse. The other carving will be exceptionally complete and clean. Here you will not find burrs, cut combs and unpleasant dents. Flanges are manufactured in compliance with the requirements of GOST 12820, GOST 12821, GOST 12815.

The insulating flange connections are assembled so well that the ends of the bolts and studs protrude only one thread pitch, or even less. The flanges also have holes for bolts and studs. They are located symmetrically on both flanges. On the details that need mechanical restoration, all burrs are removed in advance, and sharp edges, with a radius of 0.2-0.4 mm, are blunted, unless there are other additional instructions.

It is a combination of two or three flanges, between which are installed gaskets made of insulating material. Apart from gaskets, in the holes for fasteners, additional insulating sleeves. can act as an insulating material paronite, graphite and fluoroplast. Insulating flange connections (abbreviated IFS) are used to protect the pipeline or any section of the pipeline from electrochemical corrosion. Electrochemical corrosion appears on the pipeline as a result of the influence on the pipeline of electrical, or so-called "stray" earth currents. As a result of the impact of such corrosion on the pipeline, cracks are formed on the pipeline, and leakage of the transported medium may occur. Wandering earth currents appear on those parts of the earth where the earth is used as a conductive medium. These are areas located near tram or railway depots and tracks, as well as near any power plants. (IFS) isolate a section of the pipeline from stray currents by interrupting the metal structure of the pipeline with an insulating material, thereby preventing the occurrence of electrochemical corrosion. In the figure below, you can see how schematically they look :

As can be seen from the schematic diagram above, represents a With insulating gasket between flanges, as well as with bushings in mounting holes. This type is used in most cases of pipeline laying, but in the gas industry, where the transported medium is gases with an overpressure of not more than 7.0 MPa, another type is used insulating flange connections are compounds made up of three flanges. In the figure below, you can see how schematically they look insulating flange connections (IFS) consisting of three flanges:

As can be seen from the diagram above, this insulating flange connection (IFS) represents a connection of two collar flanges welded to the pipeline, through the third flange, which is between them. Between flanges also available insulating gaskets, and in the holes for fasteners are installed insulating sleeves. As a third flange, usually acts flat flange, the thickness of which does not exceed 20mm. All gaskets for IFS are covered with a special electrically insulating bakelite varnish, this is done to protect the gaskets from moisture saturation.

Insulating flange connections are of the following types

• - insulating flange connections
• - insulating wafer connections
• - detachable insulating flange connections
• - insulating flange connections one-piece

Usually, insulating flange connections (IFS) are used in pipelines in the following cases:

• near objects that are sources of stray currents;
• on branches of the pipeline from the main line;
• in order to disconnect an electrically insulated conduit from any non-insulated earthed structure;
• at the junction of pipelines that are made of different metals;
• in order to disconnect an electrically insulated pipeline from any explosive underground structure;
• when entering a heating network to objects that are sources of stray currents;
• at gas distribution points and gas distribution stations, etc.

Insulating flange connections produced according to two main regulatory documents: GOST 25660-83 and TU 3799. IFS according to GOST 25660-83 can be made in one version. In the figure below, you can see how this implementation looks schematically:

Insulating flange connections according to GOST 25660-83 are used to protect underwater, underground and surface pipelines from electrochemical corrosion at a pressure of 10.0 MPa and an ambient temperature not exceeding 80°C.

IFS according to GOST 25660-83 manufactured and assembled exclusively in the factory, because when assembling, you must follow a certain clear sequence, namely:

1. Before assembly IFS, flange sealing surface covered with a special insulating varnish.
2. Hardware with which insulating flange connection connected, isolated with bushings or insulating gaskets from flanges.
3. flanges are connected by sequential tightening of diametrically opposite studs in order to avoid their distortion.
4. After insulating flange connection assembled, ends insulating gaskets and washers, as well as the inner surface of pipes and flanges covered with insulating varnish, and flanges dried at temperatures up to 200 °C.

After assembly, insulating flange connections according to GOST 25660-83 pass certain electrical and hydraulic tests provided by the documentation developed by the manufacturer IFS, as well as checking for compliance general requirements, which are set out in the "Rules for the Design and Safe Operation of Process Pipelines". IFS according to GOST 25660-83 tested in a dry room, using a megohmmeter, at a voltage of 1000V, and insulating flanges tested both wet and dry.

Insulating flange connections according to GOST 25660-83 can withstand pressure up to 10.0 MPa, and their diameter varies from 200mm to 500mm. The table below shows all types IFS according to GOST 25660-83 supplied by our company, as well as the characteristics of the data IFS:

Insulating flange connections according to GOST 25660-83:

Conditional passage Dy	d1	D	D1	dsh	l1, sq at least	H	Weight, kg, no more
200	190	430	360	M36	2,0	293	129,6
250	236	505	430			333	195,2
300	284	585	500	M42		375	303,8
350	332	655	560	M48	2,5	405	411,3
400	376	715	620			414	502,2
(450)	456	770	675		3,0	459	615,2
500	506	870	760	M56		499	843,4

Below is an example of a conditional insulating flange connections according to