Customized Rings For Him – Metal O-rings will be the metallic variations of commonly used elastomeric O-rings. They are typically used in stationary sealing applications that are incompatible with the physical and chemical features of elastomeric O-rings. These O-rings have high tolerance to radiation as well as high vacuum, and are usually used for flanged programs. Ideally, metal O-rings are placed in both open and closed grooves and axial pressure is used between two parallel surfaces. What’s more, grooves that hold the O-rings are made to be perpendicular to the direction of the fluid stream. When placed between compressed and surfaces to a predetermined elevation, deforms and generates contact between the jointing and sealing faces. Inherently, O-rings’ metallic elasticity exhibits a affordable deflection and generates maximum sealing contacts through operation to ensure the sealing action. Besides elastic deflection of the metal, structural builds of the O-rings also play an important role in creating the sealing force. Even though most metals can be used for fabricating metal O-rings, the option of metals must be such that the linear growth co-efficient of the O-ring metal fluctuates slightly from the linear growth co-efficient of the metal(s) of jointing surfaces. Metal O-rings are vulnerable to rust unlike elastomeric O-rings, and as such, are coated with the right material to prevent rusting. This material is softer than the base metal and serves an additional purpose of preventing the impact of surface abnormalities. The coating materials that are ordinarily used are soft metals, such as silver, and non-metals such as PTFE.
Metal O-rings are primarily classified based on their basic structural attribute, they are classified as follows:
- Solid Metallic O-Rings
- Hollow Metal O-Rings
Solid Metallic O-Rings
Solid metallic rings are wires of circular profile attached like a ring. These types of O-rings require special grooves for their efficient functionality. This requirement of special grooves restricts the use of solid metallic O-rings to certain programs, such as engine cylinder heads. Solid metallic rings are usually manufactured in copper and appropriate for application in atomic reactors, for assessing radiation flows. These O-rings can manage pressures of up to 4MPa and temperatures reaching 500°C and are acceptable for moderate pressure and medium sized vacuum applications.
Hollow metallic O-rings are structurally more sophisticated in comparison with good metallic O-rings and formed by circular tubes bent into the shape of a ring. These O-rings are sub-classified dependent on the characteristics of the hollow sector of the ring.
- Plain Hollow O-Rings
- Self Energized Hollow O-Rings
- Stress Filled Hollow O-Rings
Plain Hollow O-Rings:
These are hollow metallic O-rings with nitrogen at atmospheric pressure or vacuum inside them. Plain hollow O-rings are used in low pressure or low vacuum applications. Though plain hollow O-rings show similarity in temperature and pressure handling capabilities with good metallic O-rings, they offer substantially superior spring-back and sealing capabilities. Generally, plain hollow metallic O-rings are manufactured from Inconel 750 and garnished with silver.
Self-energized hollow O-rings have vents or holes in their surfaces to use the system pressure or atmospheric pressure for sealing action. Depending upon the orientation of these grooves, the O-rings are further classified into internally vented O-rings and externally vented O-rings. Internally vented O-rings made from mild steel and garnished with PTFE can withstand pressures of up to 3500 kg/sq cm and temperatures of 600°C. Externally vented O-rings are used in applications where the external pressure is greater than the pressure inside the seal.
Stress stuffed hollow O-rings are modified plain hollow rings with pressurized inert gasses inside them. These O-rings can be used in tongue and groove flanges and will handle temperatures from cryogenic temperatures up to 850°C. Stress filled O-rings are used in vacuum sealing applications.
- Metal O-rings can’t be used in highly dynamic sealing applications
- These O-rings are rendered useless when they’re used once because they can’t keep their shape after single use
- Broad tolerances of the groove can’t be adapted by the metallic O-rings, particularly in bigger sizes
- Careful fitting ought to be done in order to prevent their deformation until their seal is tightened.