Double Jacketed Gaskets
Abbreviations
Acceptable abbreviations for identifying steel and filler material for double-jacketed gaskets.
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Steel Material AbbreviationsAbbr. Stainless steel 3-Digit AISI number Inconel 600 INC 600 Monel MON Titanium TI Nickel NI Hastelloy B HAST-B Hastelloy C HAST-C -
Fillers AbbreviationsAbbr. Natfite NF PolytetrafluoroethylenePolytetra-fluoroethylene PTFE Graphite GRAF Ceramic CER
Exchanger Gasket Style Chart
N 500 Series
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- Corrugated Solid Metal
- Style N 500
- Low pressure gasket for smooth flanges with low bolt pressure. The advantages of this gasket are its low cost and great resilience.
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- Single Jacketed with Corrugated Filler
- Style N 502
- Used in applications which require a narrow width. This is an economical gasket that answers many needs.
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- Single Jacketed Non-Asbestos Filled
- Style N 520
- Generally used on narrow width applications. The single jacket protects both edges of the filler material with its metal liner.
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- Double Jacketed Non-Asbestos Filled
- Style N 523
- This gasket has greater compressibility and resilience than a solid metal gasket. It provides even support by the use of the overlapped jacket on the inside and outside diameters. Also, the outside lap helps to prevent distortion of lightweight flanges.
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- Double Jacketed Corrugated Non-Asbestos Filled
- Style N 526
- The corrugations in this gasket act as a separate seal under moderate and even bolt loads if a leakage occurs across the inside edge.
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- Double Shell Non-Asbestos Filled
- Style N 527
- The double shell on this gasket allows greater strength and rigidity by the addition of a completely overlapping inner shell.
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- Double Jacketed Corrugated with Corrugated Metal Filler
- Style N 529
- The metal filler has greater resistance to problems resulting from temperature changes. The range of temperature is limited by the metal selected.
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- Two-Piece French Type
- Style N 531
- The soft filler is exposed on the O.D. and the size of diameter is practically unlimited.
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- Solid Metal
- Style N 540
- Use where a smooth flange face and high bolt load are needed. This gasket has great strength, good heat conductivity, resistance to temperature, corrosion and pressure.
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- Solid Metal (Profile)
- Style N 550
- Gasket with phonographic grooves machined into the gasket face. Available with soft gasket sealing material bonded to both faces.
Double Jacketed Gasket Design
Double-jacketed gaskets shall be made with a filler completely enclosed in a corrugated metal jacket. For gaskets NPS 8 and larger, the corrugation pitch shall be 0.13-inch (3.2 millimeters) minimum and 0.25-inch (6.4 millimeters) maximum. For gaskets NPS 6 and smaller, the pitch shall not exceed 0.16-inch (4.0 millimeters).
The jacket metal thickness shall be 0.015-inch (0.4 millimeter) minimum. The filler shall be 0.06-inch (1.6 millimeters thick) minimum. Other details of design, including the density of the filler shall be National Gasket standard.
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- Dimensions
- The inside and outside diameters, and the thickness of a double-jacketed gasket (including tolerances), shall conform to NPS, class,and flange standard specified in the purchase order.
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- Standard Materials
- The standard materials shall be a soft carbon steel jacket and a filler of Natfite having a suitable binder. A jacket and/or filler or other materials may be specified by the purchaser.
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- Marking
- Double-jacketed gaskets shall be tagged or, if the gasket size permits, marked with waterproof ink using symbols approximately 0.25 inch (6.4 millimeters) high, as follows:
- Flange size (NPS)
- Class
- Jacketed material identification (number, name, or abbreviation) if other than of soft carbon steel
- Filler material identification, if other than Asbestos
- Identification: API 601
- Manufacturer’s identification (trademark or name)
- API 605 for gaskets to be used with flanges conforming to API 605; M.S.S.- SP- 44 for gaskets designed for flanges conforming to M.S.S.-SP-44
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- 6” 600 304/Graph
API 601/605 (or M.S.S.-SP-44) - If the gasket is suitable for more than one class, the marking shall include all applicable classes. Typical Marking for Carbon Steel Jacketed Gasket.
- 3” 3-4-600
API 601/605 (or M.S.S.-SP-44) - The jacket material identification for nonstandard materials shall use the material abbreviations, or spell out the entire name.
- 6” 600 304/Graph
Heat Exchanger Gasket Typical Shapes
Shapes
Styles
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- Corrugated Solid Metal
- Style N 500
- Low pressure gasket for smooth flanges with low bolt pressure. The advantages of this gasket are its low cost and great resilience.
-
- Single Jacketed with Corrugated Filler
- Style N 502
- Used in applications which require a narrow width. This is an economical gasket that answers many needs.
-
- Single Jacketed Non-Asbestos Filled
- Style N 520
- Generally used on narrow width applications. The single jacket protects both edges of the filler material with its metal liner.
-
- Double Jacketed Non-Asbestos Filled
- Style N 523
- This gasket has greater compressibility and resilience than a solid metal gasket. It provides even support by the use of the overlapped jacket on the inside and outside diameters. Also, the outside lap helps to prevent distortion of lightweight flanges.
-
- Double Jacketed Corrugated Non-Asbestos Filled
- Style N 526
- The corrugations in this gasket act as a separate seal under moderate and even bolt loads if a leakage occurs across the inside edge.
-
- Double Shell Non-Asbestos Filled
- Style N 527
- The double shell on this gasket allows greater strength and rigidity by the addition of a completely overlapping inner shell.
-
- Double Jacketed Corrugated with Corrugated Metal Filler
- Style N 529
- The metal filler has greater resistance to problems resulting from temperature changes. The range of temperature is limited by the metal selected.
-
- Two-Piece French Type
- Style N 531
- The soft filler is exposed on the O.D. and the size of diameter is practically unlimited.
-
- Solid Metal
- Style N 540
- Use where a smooth flange face and high bolt load are needed. This gasket has great strength, good heat conductivity, resistance to temperature, corrosion and pressure.
-
- Solid Metal (Profile)
- Style N 550
- Gasket with phonographic grooves machined into the gasket face. Available with soft gasket sealing material bonded to both faces.