FVMQ-GASKETSO-Ring is the most common type of gasket in the world. These articles are circular cross-section rings, identified by two main dimensions: inner diameter and thickness. They are regulated by ISO Norm 3601; it establishes standard sizes and the related tolerances; it also sets a formula, by which it is possible to calculate tolerances of non-standard O-Rings. They have a high quality of the finish and can be used both for axial and radial seal. This model was born in 1882, more than 100 years ago, when Thomas Alva Edison registered an O-Ring as sealing for gas in a water-cock patent. In 1930, other licenses for the use of O-Rings were issued in North America. With the discovery of synthetic rubber, over the 30’s, they started to have their success. Rubbers have the same behaviour of a highly viscous fluid: according to Law of Hydrostatics of Blaise Pascal, basically, pressure exerted wherever in a confined fluid is transmitted equally and in all directions throughout the fluid; in this way, every squared millimeter of the part generates sealing force; furthermore, the higher is the pressure exerted by the housing, the higher is this force. In addition to their outstanding sealing qualities, O-Rings are also easy to mould, mount and maintain and do not require large housings. Hardness is another important point: in fact, it depends both on the type of housing and the fluid pressure: the more you need O-Rings that adapt better and easily to the surface structure of contact surfaces and the fluid pressure is shallow, the lower the hardness must be and vice versa. Standard hardnesses are 70, as regards static applications, and 75, for what concerns dynamic applications; normally, colour black has the highest performances, due to the presence of dark fillers, and for this, it is considered as standard.

Fluorosilicone (FVMQ) sealings can be used for the most different applications, among which we can cite the contact, at low temperatures, mainly with ozone, but they also have good resistance against oils and permanent deformation caused by mechanical forces.