Spiral Wound Gaskets
Spiral wound gaskets have become extremely popular due to the wide variety of available styles and sizes. Spiral wound gaskets can be fabricated of any metal which is available in thin strip and which can be welded;
therefore, they can be used against virtually any corrosive medium dependent upon the choice of the metal and filler. They can be used over the complete temperature range from cryogenic to approximately 1093°C (2000°F). This type of gasket can be used in all pressures from vacuum to the standard 2500 pressure class flange ratings. Spiral wound gaskets can also be manufactured with variable densities, i.e. relatively low density gaskets for vacuum service up to extremely high density gaskets having a seating stress of approximately 30,000 psi (207 MPa). The softer gaskets would require a seating stress in the range of 5,000 psi (34 MPa).
Variable Density
Spiral wound gaskets are manufactured by alternately winding strips of metal and soft fillers on the outer edge of winding mandrels that determine the inside dimensions of the wound component. In the winding process, the alternating plies are maintained under pressure. Varying the pressure during the winding operation and/or the thickness of the soft filler, the density of the gasket can be controlled over a wide range. As a general rule, low winding pressure and thick soft fillers are used for low pressure applications. Thin fillers and high pressure loads are used for high pressure applications. This, of course, would account for the higher bolt loads that have to be applied to the gasket in high pressure applications. In addition to all these advantages of the spiral wound gasket, they are relatively low cost.
Available sizes and Thicknesses
Spiral wound gaskets are available in thicknesses of 0.0625” (1.5 mm), 0.100” (2.5 mm), 0.125” (3 mm), 0.175” (4 mm), 0.250” (6.4 mm), and 0.285” (7 mm). The chart on page 47 indicates the size range that can normally be fabricated in the various thicknesses along with the recommended compressed thickness of each and the maximum flange width.
Flange Surface Finish
Use of spiral wound gaskets gives the designer and the user a wider tolerance for flange surface finishes than other metallic gaskets. While they can be used against most commercially available flange surface finishes, experience has indicated that the appropriate flange surface finishes used with spiral wound gaskets are as follows:
- 125 to 250 AARH optimum
- 500 AARH maximum
| PTFE | -325° F to 500° F |
| O2i-Oxidation Inhibited Graphite | -325° F to 850° F |
| Oxidation Resistant Grade APX2-FG | -325° F to 975° F |
| HTG (High Temperature Gasket) | -325° F to 1500° F |
| Mica | -325° F to 1832° F |
| Ceramic | -325° F to 2000° F |
| 304SS | 1400° F |
| 316SS | 1400° F |
| 321SS | 1500° F |
| 347SS | 1700° F |
| Titanium | 2000° F |
| Nickle | 1400° F |
| Monel | 1500° F |
| Inconel 600 | 2000° F |
| Hastelloy | 2000° F |
| Gasket Type | Minimum [PSI] | Optimum [PSI] | Maximum [PSI] |
| Spiral Wound W – WR – WRI – WRI-P – WRI-RJ – WRI-LE |
10,000 | 25,000 | 40,000 |
| Spiral Wound WR-LC – WRI-LC |
5,000 | 10,000 | 40,000 |
| CMG CMG – CMG-EX – CMGT – CMG-PTFE |
3,700 | 15,000 | 30,000 |
| Kammprofile LP1 – LP2 – LP3 |
3,700 | 15,000 | 60,000 |
| Double Jacket (Carbon Steel) STYLE 300 |
7,600 | 20,000 | 35,000 |
| Double Jacket (Stainless Steel) STYLE 300 |
9,000 | 22,000 | 35,000 |
| Corrukamm CK1 – CK2 |
3,700 | 20,000 | 60,000 |