An O-ring is a sealing solution used for sealing between parts of industrial machinery such as valves, pumps, agitators and in a wide range of static sealing applications.
One of the most outstanding advantages of O-Rings is their excellent cost-performance ratio, since they are a very versatile product with a very low cost and a very simple design. We show you below what an O-ring is, how an O-ring is manufactured and what applications this sealing part can have.
O-rings are used in any type of machinery, so there is a wide variety of different types of O-rings. O-ring materialsDepending on the application, the O-ring can be made of metal or elastomer. Elastomer O-rings are manufactured in large quantities, which is why their availability is very high.
The sealing operation for which an O-ring can be used can be static or dynamic. At static sealing there is no relative movement between the O-ring and the part it seals against. For example, the O-ring mounted on the sealing cap of your watch that allows it to be water resistant.
In the use of O-rings to achieve static sealing, we distinguish two very frequent situations: static sealing of axial type and static tightness of radial type. And the fact is that, following the example of the watch, the O-ring installed in its cover suffers an axial deformation in its section and for that reason its sealing is of the axial type. However, in other cases, the O-ring that prevents the entry of fluid into the piston, works by radial deformation on its inside diameter. Even if the piston moves, the O-ring works statically because it does not move relative to the piston.
Although it is not recommended because there are better alternatives to an O-ring, it can also be used in the following applications dynamic sealing, We are well aware that their useful life will be short.
This is the case of a hydraulic cylinder that has an O-ring as a piston sealing gasket and the piston moves back and forth cyclically. At applications requiring dynamic sealing, When thinking of O-rings, only radial dynamic sealing makes practical sense. The O-ring works by radial deformation on its outer diameter and seals against the cylinder liner. As the piston moves, the O-ring moves relative to its sealing surface, i.e. the cylinder liner.
We hope this article has been of interest to you. If you need more information about our custom bellows manufacturing service or technical advice, consult our team of experts.
Index
What is an O-ring?
An O-ring is shaped like a donut, i.e. it is a ring whose cross-section is in the form of a circle. In geometry, this figure is called a ‘torus’ and hence the adjective 'O-ring'. O-rings are identified by their inner diameter (25.47) and cross-section (2.00).O-rings are used in any type of machinery, so there is a wide variety of different types of O-rings. O-ring materialsDepending on the application, the O-ring can be made of metal or elastomer. Elastomer O-rings are manufactured in large quantities, which is why their availability is very high.
How is an O-ring manufactured?
Elastomer O-rings are available in large quantities and are manufactured by molding, vulcanization of the O-ring thread and machining of a dolla:- When huge quantities (millions) of O-rings have to be manufactured, the molding manufacturing method is used.
- When an O-ring of a special inner diameter is required, the O-ring thread (which resembles a very long “spaghetti”) is extruded and cut to the desired length of what is to be the future O-ring. Its ends are joined by means of a process called “vulcanization”, which consists of presenting the ends in a heatable jaw. Between both ends, a very thin film of the same material as the O-ring but raw is added, so that when temperature is applied, it becomes elastic and softens between the faces of these ends and they are joined together.
- Finally, it is also possible to manufacture an O-ring by machining a dolla, which is very useful for emergencies. Literally, the manufacturing work consists of sculpting the seal from a cylinder of material that can be solid (bar) or hollow (dolla).
What are the uses of O-rings and what type of sealing do they solve?
Every machine or piece of equipment involved in the process industry has O-rings, including the watch you are holding in your hand right now. There are O-rings in cars, motorcycles, bicycles, yachts, airplanes, sewing machines, music equipment, etc. And you should know that an O-ring solves sealing problems cheaply and easily.The sealing operation for which an O-ring can be used can be static or dynamic. At static sealing there is no relative movement between the O-ring and the part it seals against. For example, the O-ring mounted on the sealing cap of your watch that allows it to be water resistant.
In the use of O-rings to achieve static sealing, we distinguish two very frequent situations: static sealing of axial type and static tightness of radial type. And the fact is that, following the example of the watch, the O-ring installed in its cover suffers an axial deformation in its section and for that reason its sealing is of the axial type. However, in other cases, the O-ring that prevents the entry of fluid into the piston, works by radial deformation on its inside diameter. Even if the piston moves, the O-ring works statically because it does not move relative to the piston.
Although it is not recommended because there are better alternatives to an O-ring, it can also be used in the following applications dynamic sealing, We are well aware that their useful life will be short.
This is the case of a hydraulic cylinder that has an O-ring as a piston sealing gasket and the piston moves back and forth cyclically. At applications requiring dynamic sealing, When thinking of O-rings, only radial dynamic sealing makes practical sense. The O-ring works by radial deformation on its outer diameter and seals against the cylinder liner. As the piston moves, the O-ring moves relative to its sealing surface, i.e. the cylinder liner.
We hope this article has been of interest to you. If you need more information about our custom bellows manufacturing service or technical advice, consult our team of experts.