Gasket materials. Auxiliary materials Gaskets and padding materials

Omental packings according to GOST 5152-77 used for sealing valve seals, pumps, machines and equipment. They are designed for a wide range of pressures and temperatures. Being impregnated with an anti-friction compound, the packings provide lubrication to the rotating shafts and rods passing through the stuffing box.
In table. 76 is a list of gland packings that can be used in sanitary systems. Braided and rolled packings are supplied in coils (coils) packed in bags. Stuffings are stored in a container in a closed dry room together with a document certifying compliance GOST 5152-77 and marking (on the tag).
Asbestos cords on GOST 1779-72(Table 77) impregnated with an anti-friction compound or graphite mixed on natural drying oil, used for stuffing glands of fittings, compensators, sealing sections of cast-iron boilers, threaded connections. They are also used as an insulating material.

Table 76. List of steel packings.

Table 77. CHARACTERISTICS OF ASBESTOS CORDS

Asbestos cardboard according to GOST 2850-75 grades KAON-1 and KAON-2 are used as a heat-insulating and fire-retardant material at a temperature of the insulated surface of not more than 500 ° C. It is also used as cushioning material for equipment, instruments and communications. KAP brand cardboard is used as a cushioning material. Cardboard sheets should not have cracks, dents, or foreign mechanical inclusions.
Cushioning cardboard GOST 9347-74 are produced in sheets and rolls with a thickness of 0.3; 0.5; 0.8; one; 1.5 mm - grade A (impregnated), 0.3; 0.5; 0.8; one; 1.25; 1.5; 1.75; 2; 2.25; 2.5 mm - grade B (non-impregnated). Cardboard density 0.7-0.75 g/cm³. The surface of the cardboard must be even, without warping, folds, wrinkles, bubbles, non-fibrous inclusions and pressure marks.
Gaskets are used to seal flange joints of pipelines transporting water with a temperature of up to 100 ° C from gasket cardboard.
Before installation, the gaskets must be soaked in water and boiled in natural drying oil.
Rubber plates and rubber fabric GOST 7338-77 used for the manufacture of gaskets, valve seals, shock absorbers and other parts, acid-alkali-resistant, heat-resistant, frost-resistant and oil and petrol resistant. The length of sheets or strips of plates is 0.5-10 m, width 200-1750 mm and thickness 0.5-50 mm. Heat-resistant rubber plates remain operable when operating in air at temperatures up to 90 ° C and in water vapor at temperatures up to 140 ° C. Frost-resistant rubber plates remain operable in operating conditions at temperatures up to -45 ° C. Rubber plates of all types remain heat-resistant during operation within temperatures from -30 to +50 ° С.
A sheet rubber plate is used for the manufacture of flange gaskets for pipelines. cold water. The rubber-fabric plate is used at water temperatures up to 100 ° C.
Paronite on GOST 481-71 made from a mixture of asbestos fibers, solvent, rubber and fillers. Produced in the form of sheets with a thickness of 0.4; 0.6; 0.8; 1.5; 2; 3; 4; 5 and 6 mm, sizes 300X400, 400X500, 500X500, 750XYOOO, 1000X1500, 1500X1500 and 3000X1500 mm. From paronite general purpose(PON) make gaskets for flange connections of pipelines hot water and steam with temperatures above 100°C.
Before installation, the gaskets are moistened in hot water and lubricated with graphite mixed with natural drying oil.
Paronite must not be stored together (in the same room) with organic solvents, lubricating oils, acids and other substances that destroy it
Fiber sheet according to GOST 14613-69 issued eight brands. Fiber brand FPC (oxygen-resistant gasket), manufactured with a thickness of 0.6 to 5 mm, is used as gaskets for neutral gaseous media (oxygen, carbon dioxide, etc.) when high pressures and normal temperatures. Fiber must be thoroughly degreased before use. Fiber brand FT (technical) is used as a sealant in valves and taps of hot water supply systems.
Flax ragged according to GOST 10330-76 in the form of a strand impregnated with minium or white lead diluted on natural drying oil, it is used as a sealant in threaded joints of pipelines transporting water with a temperature of up to 105 ° C.
FUM - fluoroplastic sealing materials in the form of a tape 10-25 mm wide and 0.08-0.12 mm thick and a cord (for flange gaskets). The tape is used to seal threaded connections of pipelines Dy - 65 mm, a cord for sealing locknuts, and also as a stuffing box for valves and taps. They should be light in color.
The FUM seal is water-resistant and withstands temperatures from -60 to +200°C.
Resin strand (cabole) is a bast fiber treated with wood resin, obtained as waste in the manufacture of hemp and flax fibers. A strand of two grades is produced: the first grade is made from hemp fiber, the second grade is made from a mixture of hemp and flax fibers. The strand is used to seal the sockets of cast-iron and ceramic pipes.
Hemp rope GOST 483-75, impregnated with resin or without impregnation, is used to seal the sockets of cast-iron and ceramic pipes. The strand is impregnated with resin to protect it from decay.

In gas supply systems at the installation sites of devices and instrumentation, threaded and flanged connections are used. Such connections are characterized by insufficient tightness. To seal the joints, gaskets and sealing materials should be used, to which the following requirements are imposed:

• the gasket material must retain its physical properties and not be subject to corrosion;
• there must be no deformation of the sealing surface;

• material must meet the requirements mechanical properties;
• as far as possible, it should be inexpensive and accessible.

For the manufacture of gaskets, a large number of

various materials.

Paronite (GOST 481-80). It is made from asbestos and rubber by vulcanization and rolling under high pressure; designed for sealing flat connectors with various media. Paronite is a universal gasket material and is used for cold and hot gases, air, oils, petroleum products, etc. (Table 10.1). Depending on the purpose, it is produced in seven grades. Of these, PMB grades (for liquefied and gaseous hydrocarbons) can be recommended for limiting pressures up to 1.6 MPa and a temperature range from -40 to +60 ° C. Paronite MPB is produced with a thickness of 0.4; 0.5; 0.6; 0.8; one; 1.5; 2; 2.5; Zmm, sheets 500,1000,1500 mm long and 500,750,1000 mm wide. Paronite gaskets are impregnated with cylinder oil and coated with graphite powder. They must comply with the requirements of GOST 15180-70.

Plastics. Plastics are used for flanged connections of gas pipelines various kinds, similar in elasticity to rubber: plastic compound and polyethylene high density. PVC compound is used, and high-density polyethylene (VD) according to GOST 16338-77 and low density (ND) according to GOST 16337-77E with a thickness of 1-4 mm, fluoroplast-4 (PTFE) with a thickness of 1-4 mm according to GOST 10007-80E and gasket tape made of fluoroplast-4 (PTFE) according to GOST 18999-73 is used for the manufacture of gaskets for flat and round section, as well as for complex gaskets, in which the core is made of asbestos, rubber or corrugated steel, and the lining is made of fluoroplast.

Technical sheet rubber(GOST 7338-90) is supplied in sheets and rolls. This material has a high elasticity, which makes it possible to achieve a density between metal surface and gasket at low clamping forces. Rubber is a chemically resistant material, impervious to gases and liquids. For gaskets, it is usually recommended to use sheet technical rubber according to GOST 7338-90 without fabric gaskets, since in the presence of interlayers, seepage can sometimes occur. By hardness, it is divided into soft (m), medium hard (s) and high hardness (n). By resistance to heat-resistant (T) and frost-resistant (M). It is recommended to use oil and petrol resistant rubber (MB) grades A and B, depending on the degree of resistance.

Annealed aluminum sheets(GOST 2 1 631-76), copper sheet soft(GOST 495-92). Metal gaskets are made from these materials, which provide sufficient density at high pressures and medium temperatures. The disadvantages include the need to create large efforts to ensure the tightness of the connection, insufficiently elastic properties and relatively high manufacturing costs. For gaskets, it is recommended to use annealed aluminum sheets in accordance with GOST 13722-78 and GOST 21631-76 or annealed aluminum and aluminum alloy tapes in accordance with GOST 13726-78, soft sheet copper grades Ml and M2 in accordance with GOST 495-92.

To give the gaskets fire-resistant properties, you can use:

• asbestos cardboard (GOST 2850-80) grades KAON-1, KAON-2. Cardboard sheets 900 x 900, 1000 x 800, 1000 x 900 and 1000 x 1000 mm are available in thickness 2; 2.5; 3; 3, 5; 4; 5 mm;
• asbestos reinforced fabric (GOST 2198-76). It is a rubberized and graphitized fabric of plain or twill weave based on brass wire, and on the weft - from asbestos yarn reinforced with brass wire. Sheets of cardboard with a width of 1000 and 750 mm and a length of at least 1500 mm are produced with a thickness of 0.6; 0.7 and 1.1 mm. Corrugated metal gaskets are also used with

soft packing used for nominal pressure from 1.6 to 4.0 M Pa and temperatures up to 450 °C. For the manufacture of shells of corrugated gaskets with packing, soft annealed aluminum sheet (GOST 21631-76 and 13726-97) 0.3 mm thick or a sheet of soft annealed low carbon steel 0.3 mm thick. The stuffing of metal corrugated gaskets is made from whole sheet asbestos according to GOST 2850-80.

To seal threaded joints, a linen strand should be used in accordance with GOST 10330-76, which, during the connection, is coated with red lead in accordance with GOST 19151-73 or white lead in accordance with GOST 12287-77, mixed with drying oil in accordance with GOST 7931-76, fluoroplastic material (FUM) in the form tape according to TU 6-05-1388-70 grade 1 and cord according to MRTU 6-05-870-66 grades B and K, as well as other sealing material that ensures the tightness of the connection.

For sealing detachable connections between flanges

place pads of elastic material. When tightening

the gasket bolts are deformed and a strong-tight joint is created

unity.

Gaskets must be sufficiently strong and elastic

nym to seal the connection well and perceive

internal pressure and temperature elongation of pipelines.

In addition, they must retain their physical characteristics

sticks under the action of an aggressive environment. Material for laying

the dock is chosen taking into account the working pressure, concentration and temperature

peratury aggressive environment, cost and scarcity.

For detachable flange connections of equipment and pipe

wires use cardboard, asbestos, polypropylene, textolite,

lead, copper, aluminum and other materials.

Cardboard in the form of sheets with a thickness of 0.2 to 2.5 mm is used

for sealing flange connections oil and brine

wires. To protect against soaking pads made of cardboard

not pre-soaked in hot engine oil or

drying oil. Asbestos sheet gaskets are used in gas pipelines.

waters of dry corrosive gases with temperatures up to 600 °C. Pro-

how easily they break under pressure.

Paronite, which is a compressed mixture of

asbestos (60–70%), rubber (12–15%) and mineral fillers

agents (including 1.5–2.0% sulfur), is the main pro-

base material for steam pipelines. It is widely used

also for sealing pipelines transporting mines

ral acids and alkaline solutions at temperatures up to

150–170 ÉС and pressure not more than 0.3 MPa. For sealing gas

wires, paronite gaskets are used for smooth flanges

tsakh up to a pressure of 2.5 MPa, and with flanges with a ledge and a cavity -

For cold and hot water, weak solutions of mineral

acids and alkalis at temperatures up to 50–100 °C as

gasket material, you can use the appropriate

rubber grades, in particular based on polysiloxane rubber,

which is capable of operating in the temperature range from -65 to 250

EU. Polyisobutylene PSG, produced in the form of sheets with a thickness of

2.5 and 4 mm, used to seal pipelines of weak acid

slot and alkalis. Due to cold flow, polyisobutylene is used

they are operated at pressures not higher than 0.05 MPa and temperatures Ò40 ÉC.

Polyisobutylene composition has improved strength

with polyethylene. This material is used as a gasket

dock for glass pipelines at temperatures from -30 to

"Pure" polyethylene can also serve as a gasket.

(without additives). It is used, for example, in the production of reagents

hydrochloric acid.

Fluoroplast as a gasket is usually used in

tanks to obtain products of reactive qualification and

highly pure substances. Compressed gaskets

compositions of fluoroplast-4D and fillers (asbestos, glass-

lock, barium sulfate, etc.), are able to work in the range

temperatures from –195 to 250 °C and at pressures up to 5 MPa. Fluoro-

the formation is very stable, it is used in the form of a thin tape for

wrapping paronite gaskets in the production of diluted

nitric acid.

Plastic gaskets made of lead, copper and aluminum serve

for sealing high pressure pipelines. Wherein

their corrosive behavior in the given environment should be taken into account.

To ensure the tightness of stuffing box seals

machines and apparatuses use packings and stuffing materials

ly: cotton, hemp and linen yarn for non-aggressive

environments; asbestos yarn, fiberglass, plastics, soft

thalls and pressed graphite at high pressures.

Stuffings are round, square cords woven from yarn.

military and rectangular section. If they are used in sal-

shafts and rods, then they are impregnated with antifriction compounds

use fluoroplast F-4DP. To increase the strength of the cord

their ditch is reinforced with copper or brass wire. At present

time, the industry has mastered an elastic sealing

material FUM from oiled powder of fluoroplast-4D. His

used as chemically resistant and heat resistant (150

EC) self-lubricating packing material.

To seal flange joints, flat elastic gaskets made of paronite, rubber, cardboard, fluoroplast-4 and composite materials based on them. According to GOST 15180-86, the design of gaskets, depending on the design of the sealing surfaces of the flanges, must correspond to the data indicated in Table. 1 and 2.

Table 1

Gasket designs	Versions of sealing surfaces according to GOST 12815-80	Drawing
BUT	1
B	2; 3
AT	4; 5
G	8; 9
D	1; 5

table 2

Gasket materials must have: elasticity, resistance to the environment in which they work, retain their physical properties when operating temperature environment and not corrode. When using metal gaskets, the metal should not plastically deform the sealing surfaces of the flange, so the metal of the gaskets should have a hardness and yield point lower than the metal of the sealing surfaces of the flanges, should not form with the metal gas equipment galvanic couple.

paronite(GOST 481-80). They are made from asbestos and rubber by vulcanization and rolling under high pressure. It is a universal gasket material for sealing flat connectors with various media (cold and hot gases, air, steam, oils and petroleum products, etc.). Depending on the purpose, paronite is produced in seven grades. For sealing joints on gas pipelines natural gas and in liquefied gas installations, it is recommended to use paronite of the PMB brand (in the temperature range from -40 to +60 ° C and maximum pressure up to 1.6 MPa). Paronite PMB is produced in sheets 500, 1000, 1500 mm long and 500, 750, 1000 mm wide, 0.4 thick; 0.5; 0.6; 0.8; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0 mm. The dimensions of paronite gaskets must comply with the requirements of GOST 15180-86. Before installation, the paronite gasket should be coated on both sides with dry graphite powder to prevent it from “sticking” to the flange plane.

plastics. For gaskets of flange joints of gas pipelines, various plastics can be used: high-density polyethylene (HD) according to GOST 16338-77 and low density (ND) according to GOST 16337-77E, 1-4 mm thick, fluoroplast-4 (PTFE) 1-4 mm thick according to GOST 10007-80E.

Rubber. High elasticity makes it easy to achieve tightness between the metal surface of the flange and the gasket with low tightening forces. Rubber is practically impervious to gases and liquids, has sufficient chemical resistance. Since excessive compression worsens the properties of rubber, its deformation must be limited to 30-50% of the allowable. Industrially produced technical sheet rubber without fabric or other gaskets according to GOST 7338-77 is intended for the manufacture of gaskets, valves and other parts and is produced in five types: acid-alkali-resistant, heat-resistant, frost-resistant, oil and petrol resistant and food grade.

Depending on the hardness, technical rubber is divided into soft (m), medium hard (s) and high hardness (n).

Depending on the resistance to oil and gasoline, oil and petrol resistant rubber is divided into grades A and B.

For flange connections of gas distribution systems with a working pressure of up to 0.6 MPa, it is recommended to use gaskets made of sheet oil and petrol resistant rubber (MB) of grades A and B (without a fabric base) in accordance with GOST 17133-83 and GOST 7338-77 with a thickness of 3-5 mm.

Cardboard. If, according to the working conditions, the gaskets require fire-resistant properties, then for their manufacture it is recommended to use:

• asbestos cardboard (GOST 2850-80) grades KAON-1, KAON-2. Produced in sheets with dimensions 900×900, 1000×800, 1000×900 and 1000×1000, thickness 2; 2.5; 3; 3.5; 4; 5 mm;
• asbestos reinforced fabric (GOST 2198-76) is a rubberized and graphitized fabric of plain or twill weave based on brass wire, and for weft * - from asbestos yarn reinforced with brass wire. Sheets of canvas are produced in sizes 750 × 1500, 1000 × 1500 and a thickness of 0.6; 0.7; 1.1 mm.

Metal spacers for flange and other types of connections are made from sheet metal in the form of flat rings. Metal gaskets provide sufficient density at high pressures and temperatures of the medium, have a linear expansion coefficient close to that of the flange material. The disadvantages of using metal gaskets include the need to create large efforts to ensure the connection plane, the relatively low elastic properties of the gasket material, and the high cost compared to elastic gaskets. For sealing the connection of parts, equipment of liquefied gas installations and on gas pipelines of all pressures, the recommended materials for the manufacture of metal gaskets are:

• annealed aluminum sheet in accordance with GOST 13722-78, strips of aluminum or aluminum alloys (annealed) in accordance with GOST 13726-78, GOST 21361-76, 1-4 mm thick;
• sheet copper soft marks M1, M2 according to GOST 495-77.

• linen combed strand (according to GOST 10330-76), which, in the process of joining, is impregnated with red lead (according to GOST 19151-73) or white lead (according to GOST 12287-77), diluted with drying oil (according to GOST 7931-76);
• tapes made of fluoroplastic-4 (FUM-V), 0.1-1.5 mm thick according to TU 6-05-1388-70;
• other sealing material that ensures the tightness of the connection.

Fluoroplastic sealing material of the FUM-V brand is the most effective as a stuffing material for glands of stop valves. Available in round section with a diameter of 2.0-16.0 mm and square section from 5x5 mm to 16x16 mm for use as a chemically resistant self-lubricating packing material (in movable gland type joints) and gasket material (in fixed joints). The joints operate in the temperature range from -60 to +150 °C and at pressures up to 6.0 MPa (manufacturer JSC "Plastopolymer", St. Petersburg).

Characteristics of domestic sealing materials are presented in tables 3 and 4.

* Weft - the transverse direction of the thread in the fabric.

Table 3