O-Ring Types and O-Ring Material Makeup - A Guide
Rubber O rings are a form of gasket or seal that features a round cross-section. They are commonly used to prevent leaks of either fluids or gases from occurring in products, systems, or machinery and find use across a variety of industries. Because of their low cost, simple production process, ease of installation, and pressure resistance, they have found application in a lot of common products, such as automobiles and engines. The aerospace industry useso-ringsin many types of rockets and aircraft applications.
This article will review information on the types of o-rings and material options available, along with their suitability for different applications.
The fact that o-rings can function in so many applications is largely attributable to the fact that there is a wide range of materials available from which they may be fabricated.This range of selection allows the designer to consider the properties of the material and select a suitable option based on how well that material performs against the expected operating conditions of the application. The factors that are usually considered when selecting a material for an o-ring include:
The material’s compressibility or hardness (durometer)
The performance against environmental and operational conditions, including:
The abrasion performance of the material
The permeability of the material (permeation)
The cost of the material
O-rings are usually produced from some form of elastic polymer or elastomer. These polymers are cured, often through vulcanization, resulting in improved strength, durability, and elasticity. Different materials have different properties, though, with some exhibiting greater elasticity and others possessing more tear-resistance.
Temperature range:Between -100 degrees Fahrenheit and 500 degrees Fahrenheit.
Suited for:PurePTFE O ringsare very rigid and hard to apply, butPTFEencapsulated o-rings handle surface wear well, in addition to exhibiting corrosion and abrasion resistance, non-permeability, chemical inertness, and low absorption.
Avoid:Like silicone,PTFEis rigid and is better suited to static applications.
Applications:Examples of PTFE o-ring uses include automotive steering devices and paint guns.
Solid O-ring is solid-rubber seals that are shaped like a doughnut. When pressed between two mating surfaces, O-rings block the passage of liquids or gases.
Types of Seals
O-rings can form a static or dynamic seals. A static seal is where the O-ring does not move and is used simply for containing pressure or maintaining a vacuum.Dynamic sealscan be reciprocating (like a piston and cylinder), or rotating (shaft rotating in a housing). Straight threads used with O-rings provide a better seal than tapered threads used alone.
A boss seal is also an O-ring, however it does not fit the standard sizes for an O-ring. A boss is a cylindrical projection on a casting or forging. The end of that projection is machined to provide a flat, smooth surface for sealing.
Axial squeeze and radial squeeze are two methods for applying an O-ring. An axial squeeze is when the ring is compressed parallel to a line drawn through the center or axis of the ring. In a radial squeeze the ring is compressed between the internal diameter (ID) and overall diameter (OD).
Imporant specifications for hollow O-ring include size, material, hardness rating and features.
Rubber X-ring is a torus (donut) shaped seal with a clover shaped cross section. Because of the clover design, the X-ring has a lower coefficient of friction and has multiple sealing surfaces on each side increasing its sealing ability and reduces the amount of force needed to seal and so extends the life of the seal. X-Rings are interchangeable with O-rings especially where lower coefficient of friction values are required.
Rubber V-ring is used for rotating shafts in an extremely wide range of applications. The V-ring can be used alone to protect a wide assortment of bearing types from contaminants while reliably retaining the lubricant. They are also often used as secondary seals to protect primary seals in highly contaminated environments.
V-rings are installed on shafts and their thin, tapered lip seals against a counterface perpendicular to the shaft. V-rings have an interference fit on the shaft, rotate with it and act as flingers. Angular misalignment of the shaft relative to the counterface can be tolerated. V-rings provide reliable sealing even if the shaft is out-of-round or rotates eccentrically. The amount by which the shaft can be displaced axially is governed by the permissible displacement of the V-ring relative to its counterface.
V-rings are made entirely of elastomers without fabric or metal reinforcement and are therefore easy to install. They can be stretched and, depending on size, pushed over other components like flanges, pulleys or even housings. This is a very valuable feature, especially when replacing a seal.
Four Reasons to Use Air Hoses Instead of Hydraulics
In the manufacturing world you might ask when or why should I use air hose instead of hydraulic hose?Pneumatics follow the same power movement principle as hydraulics except it involves the movement of gases instead of fluids.While pneumatics and hydraulics each have their ideal places in a wide range of industrial operations, there are times when it’s beneficial to use air hoses to meet your needs.
High Quality Of PTFE Rod From Tenglong Sealing
PTFE Rodhas excellent resistance to most chemicals and solvents and is capable of operating at high and low temperatures. It also has a very low coefficient of friction and is commonly used in food contact applications. It provides good thermal stability and has good electrical properties, but is not suitable for wear application and is difficult to bond.