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No.1 Shengli East Road, Huangqiao Economic Development Zone, Taixing City, Jiangsu Province
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Jiangsu Hengfeng New Materials Co., Ltd
Graphite wrapped gasket
NegotiableUpdate on 08/17
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Overview
The most widely used graphite wound gasket currently is the one with better resilience among semi metal sealing gaskets. It is made by alternately winding V-shaped or W-shaped thin steel strips with various fillers
Product Details
The most widely used type of graphite wound gasket is currently the one with better resilience among semi metal sealing gaskets. It is made by alternately winding V-shaped or W-shaped thin steel strips with various fillers. By changing the material combination of the gasket, the chemical corrosion problem of various media on the gasket can be solved. To strengthen the main body and accurately locate it, metal inner reinforcement rings and outer positioning rings are used to control its greater compression and avoid the scattering of the basic body. The presence of the outer ring makes it easier to install the gasket, which is generally used in flat and convex flanges of medium and low pressure
Performance characteristics of graphite wrapped gasket: It can withstand high temperature, high pressure, and adapt to use under ultra-low temperature or vacuum conditions. The surface accuracy requirement for the flange sealing surface in contact with the gasket is not high, and it is easy to disassemble and assemble
Equipment used for wrapping gaskets: Sealing flange connections in pipelines, valves, pressure vessels, condensers, heat exchangers, towers, manholes, handholes, and other industries such as petroleum, chemical, metallurgical, power, shipbuilding, and machinery.
Structural form, code, and flange category for wrapped gaskets:
| fundamental type | code | Applicable flange sealing surface | Thickness (mm) | |
| V-shaped basic body/ring | W-shaped basic body/ring | |||
| Basic type | Type A or R | Mortise and tenon surfaces, concave convex surfaces, flat surfaces, and groove surfaces | 3.2; four point five | 4.8; 5.5; seven point five |
| Inner ring type | B or RIR type | Mortise and tenon surfaces, concave convex surfaces, flat surfaces, and groove surfaces | 3.2/24.5/3 | 4.8/3.05.5/4.07.5/5.0 |
| With positioning ring | C or CG type | Flat or convex surface | ||
| Equipped with inner ring and positioning ring | D or CGI type | Flat or convex surface | ||
Material:
1. Wrapped with inner and outer rings, metal tape
A. Cold rolled steel strips such as SUS304, SUS316L, SUS321 with a thickness of 0.15mm~0.25mm shall be used, or determined through negotiation between the supply and demand parties.
B. The metal strip should be a pre formed V-shaped or W-shaped narrow strip with a smooth surface Clean, there should be no roughness or unevenness crackle. Scratches Defects such as dents and rust spots
C. The hardness value of stainless steel HV ≤ 200
2. Non metallic tape with inner and outer loop wrapping pads
A. Non metallic fillers include specially made asbestos tape, flexible graphite tape, polytetrafluoroethylene tape, non asbestos fiber tape, and mica tape. The thickness of the tape is 0.3-1.0mm.
B. The burning loss of special asbestos must be ≤ 25%
C. The chloride ion content of non-metallic strips is ≤ 100PPM
D. Recommended operating temperatures and pressures for various media and non-metallic tapes
Main technical parameters of various non-metallic materials for wrapped gaskets:
| material | Identification code | Temperature ℃ | Greater work pressure | Applicable Medium | Compression rate% | Rebound rate% | Stress relaxation rate% |
| EXPANDED GRAPHITE | F.G. | -220--550 | 250 BAR | corrosive media | 18--30 | ≥17 | ≤18 |
| Specially made asbestos tape | ASB | -150--450 | 100 BAR | General airtightness | 18--30 | ≥19 | ≤28 |
| PTFE | PTFE | -200-- 250 | 100 BAR | corrosive media | 18--30 | ≥15 | ≤13 |
| Asbestos free material | NAF | -100--350 | 100 BAR | General airtightness | 18--30 | ≥19 | ≤28 |
| Mica | MICA | -150--800 | 100 BAR | Ultra high temperature | 18--30 | ≥19 | |
| Ceramics | CER | -200--1090 | 100 BAR | Ultra high temperature | 18--40 | ≥19 |
The following table is used for material selection of graphite wound gaskets:
| Material name | Abbreviation marking | Hardness (HB) | Temperature (° C) |
| SUS 304 | 304 | 130~180 | -195~+550 |
| SUS 316L | 316L | 130~180 | -100~+550 |
| SUS 321 | 321 | 130~190 | -195~+760 |
| HASTELLOR-B2 | HASTB | 215 | -185~+1090 |
| INCONEL-600 | INC600 | 150 | -100~+1090 |
| MONEL-400 | MON | 150 | -130~+820 |
| Titanium | T2 | 215 | -195~+1090 |
Thickness tolerance of graphite wrapped gasket basic body:
| project | Thickness (mm) | Tolerance (mm) |
| Gasket thickness | 4.5, 3.2 | +0.2-0.1 |
| Ring thickness | 3.0 | ±0.25 |
The following table shows the diameter tolerance of graphite wrapped gaskets (i.e. nominal pipe diameter for flanges):
| DIN (mm) | ANSI B16.5 BS1560 (mm)Mss sp-44 | API 605 | public errand | |
| Inner ring inner diameter gasket inner diameter | <=600 | <=24" | >=26" and <=34" | ±0.5 |
| >600 and <=800 | >24" and <=34" | >=36" and <=60" | ±0.9 | |
| >800 and <=1600 | >34" and <=60" | ±1.3 | ||
| >1600 | >60" | ±1.6 | ||
| Outer diameter of gasket | <=600 | <=24" | <=24" | ±0.9 |
| >600 and <=16000 | >24" and <=60" | >24" and <=60" | ±1.8 | |
| 1600 | >60" | ±2.2 | ||
| Outer diameter of outer ring | >=1/2" and <=60" | ±0.9 | ||
| <=600 | <=24" | 0-1.0 | ||
| >600 and <=1000 | >24" and <=34" | 0-1.8 | ||
| >1000 and <=1600" | >34" and <=60 | 0-2.2 |
Main performance parameters of graphite wrapped gasket:
| Spiral gasket coefficient | m=2.5-4 |
| Spiral gasket usage pressure | ≤25MPa |
| Temperature for using wrapped gaskets | -196 ℃ -700 ℃ (not higher than 600 ℃ in oxidizing media) |
| Minimum pre tightening pressure ratio for wrapped gaskets | y=68MPa |
Technical standards:
1. The foreign manufacturing standards for graphite wound gaskets include ASME B 16.20, ASME B 16.5, ASME B 16.47 A (B), BS EN1092, JIS, and NF, etc
2 . Domestic standards include
HG20610-2009 Spiral Gasket for Steel Pipe Flanges, Ministry of Chemical Industry, European System
HG20631-2009 Spiral Gasket for Steel Pipe Flanges, Ministry of Chemical Industry, American System
GB/T4622.2-97 Gasket size standard for wrapped gasket pipe flanges
JB/T4719-92 Mechanical standard for wrapped gaskets for shell and tube heat exchangers
JB/T90-94 Mechanical Department Standard for Spiral Gaskets for Pipeline Flanges
JB/T4705-2000 Mechanical Department Standard for Spiral Gaskets for Pressure Vessel Flanges, etc. For more standards or requirements, please call us for consultation
