SPIRAL WOUND GASKETS
Spiral wound gaskets have the ability to recover under the action of fluctuating loads caused by process fluid pressure and temperature changes, flange face temperature variations, flange rotation, bolt stress relaxation and creep. The gasket sealing element consists of a pre-formed metallic winding strip with layers of a softer, more compressible sealing material which, during compression, is densified and flows to fill imperfections in the flange surfaces. The metal strip holds the filler giving the gasket mechanical resistance and resilience.
Maxiflex spiral wound gaskets combine the ease of sealing a graphite, PTFE or mica filler with the strength afforded by a specially profiled metallic, spring-like reinforcement. The sealing element is manufactured by interleaving plies of alternating metallic winding strip and filler to create a gasket that is robust and easy to install. Maxiflex spiral wound gaskets create a very tight and reliable seal suitable for high temperature and pressures and can be manufactured to suit standard flanges and also custom-designed vessels.
Maxiflex gaskets are capable of giving an excellent seal over a wide range of flange surface finishes, but as a general guide we suggest under general duties, a flange surface finish of 125-248 µin (3.2 – 6.4 µm)
Maxiflex Spiral Wound Gasket Construction
Several layers of specially formed continuous chevron-shaped metal strips are spirally wound with alternate plies of soft filler strip to make the gasket’s basic sealing element. The chevron profile allows the gasket to act as a spring and the depth is carefully controlled to give the sealing element the best compression and recovery characteristics. Maxiflex spiral wound gaskets are manufactured to specifications of ASME B16.20.
Computer controlled winding machines carefully monitor and adjust the tension of the winding strips. A uniform density throughout the product is produced. This provides the spring like action within the gasket that resists buckling and maintains a seal even when subject to fluctuating compressive loads.
Maxiflex Thickness After Installation
Spiral wound gaskets are manufactured in a number of standard thicknesses which are designed to compress to a specific thickness to attain the best sealing performance and adaptation to the flanges. The thickness is measured to the metallic windings not to the filler.