Typical high pressure applications where gaskets are used include pressure vessels, pumping equipment, as well as pipework and valve assemblies used in industrial and resource extraction/processing applications. In these applications, it is necessary to use gaskets which are capable of withstanding the high operating pressures typically encountered.
For high pressure applications, gaskets of the following types are generally used:
Non-metallic gaskets. These gaskets are generally made from composite sheet materials, including elastomers (graphite, PTFE, etc.), aramid or glass fiber, or other flexible materials. They are typically used to seal flat-face and raised-face flanges in applications where somewhat lower pressures prevail.
Semi-metallic gaskets (including spiral-wound). These gaskets are made from composites of metal and non-metallic materials. The metal gives the gasket additional strength and resiliency, while the non-metallic portion provides some flexibility, as well as conformability and sealability. Commonly used semi-metallic gaskets are the spiral wound and camprofile (grooved) types, as well as gaskets made from graphite sheet containing metal or foil inserts.
Spiral-wound gaskets are an example of a widely-used type of semi-metallic gasket. Camprofile gaskets are often used in industrial power plants, as well as the heat exchanger applications found in nuclear power installations where high pressures and bolt loads need to be controlled.
Semi-metallic gaskets are designed for the operating conditions found in most high-pressure applications. They are typically used on raised face, male-and-female, and tongue-and-groove flanges.
Metallic gaskets. These fall into two main types: metal jacketed gaskets and metallic gaskets for RTJ (Ring-Type Joints) flanges. Metal jacketed gaskets consist of a metal shell with a metal or non-metallic filler. The presence of the filler material gives the gasket resilience, while the metal jacket protects the filled core and resists pressures, temperatures and corrosion. These types of gaskets are often used in heat exchangers, as well as pumps and valves. A limitation of these types of gaskets is that they require smooth and flat flange surfaces, as well as high bolt loads, to seal effectively.
Metallic gaskets for RTJ applications were originally developed for use in oil field drilling and completion equipment. They are commonly used on valves and pipework, as well as pressure vessels.
CRG can supply non-metallic and semi-metallic gaskets for high pressure applications. These are described below:
CRG can manufacture non-metallic gaskets suitable for high pressure applications. These gaskets are precision-cut from high purity graphite sheet, oxidation-resistant graphite sheet, or graphite sheet with metal inserts. Our standard-grade graphite gaskets can support application pressures up to 2000 psi. For applications involving higher pressures, CRG can also supply gaskets made from Teadit GR1700 Sigraflex APX2 Hochdruck material. This high-strength, multilayer material, which is superior to standard grades of graphite foil, can support a working pressure resistance of 3600 psi and a maximum service temperature of 650°C (1202°F).
We can supply the following types of spiral wound gaskets:
911/911T. This is the simplest style of spiral wound gasket, consisting of a circular winding without centering or inner rings. Style 911 gaskets are mainly used in tongue and groove or male and female flange connections. They are also used in equipment with space and weight limitations.
911M. A spiral wound gasket consisting of a sealing winding with an inner ring. The purpose of the ring is to fill out the space between the flanges, avoiding turbulence in the flow of the fluid being sealed, or as a protection against corrosion or erosion. It is also used as a compression limit when the seating stress is greater than 30,000 psi (210 MPa). Since gaskets with PTFE filler have a tendency to buckle inwardly, the use of an inner ring is recommended if the gasket is to be installed with a non-confined inside diameter.
913. This gasket is constructed of a circular metal winding with an outer guide ring. The sealing element is made of the specified metal and soft sealing material. Standard pipe size gaskets are made to ASME B16.20 (see also style 913M). These gaskets are used in a very wide variety of applications.
913M. A spiral wound gasket consisting of a standard spiral wound gasket with an inner ring. The purpose of this ring is to fill out the space between the flanges, avoiding turbulence in the flow of the fluid being sealed, or as protection against corrosion or erosion. It is also used as a compression limit. As noted above, since gaskets with PTFE filler have a tendency to buckle, the use of an inner ring is required by ASME B16.20. Inner rings are also required with ASME standard spiral wound gaskets with flexible graphite fillers, unless the purchaser specifies otherwise, and some sizes and pressure classes require inner rings regardless of filler material.
914. These spiral wound gaskets have windings in non-circular forms, such as oval, rectangular and square (with rounded corners), diamonds, oblong or pear shaped. Style 914 gaskets are used in boiler handholes and manholes, equipment, engine head-gaskets and exhaust systems. Inner rings should also be used for many of these applications.
To find out more about the gaskets for high pressure applications which CRG can supply, please contact our sales team at firstname.lastname@example.org.
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