Standard O-Rings

O-Rings offer the designer an efficient and economical sealing element for a wide range of static or dynamic applications. Inexpensive production methods and its ease of use have made the O-Ring the most widely used seal. A wide choice of elastomer materials for both standard and special applications allow the O-Ring to be used to seal practically all liquid and gaseous media. O-Rings are vulcanized in moulds and are characterized by their circular form with annular cross section. The dimensions of the O-Ring are defined by the inside diameter d1 and the cross-section d2.

Compared with other sealing elements, the O-Ring has a wide range of advantages:

• inexpensive, allows low cost solutions;
• simple, one piece groove design reduces hardware and design costs;
• compact design allows smaller hardware;
• easy, foolproof installation reduces risk;
• applicable to a wide range of sealing problems, static, dynamic, single or double acting;
• wide compound choice for compatibility with most fluids;
• ex stock availability.

O-Rings are used as sealing elements, as energizing elements for hydraulic slipper seals and wipers and thus cover a large number of fields of application. There are no fields of industry where the O-Ring is not used. From an individual seal for repairs or maintenance to a quality assured application in aerospace, automotive or general engineering.

The O-Ring is used predominantly for the following static sealing applications:

• as a radial static seal, e.g. for bushings, covers, pipes, cylinders;
• as an axial static seal, e.g. for flanges, plates, caps.

O-Rings in dynamic applications are recommended only for moderate service conditions. They are limited by the speed and the pressure against which they are to seal:

• for low duty sealing of reciprocating pistons, rods, plungers, etc;
• for sealing of slowly pivoting, rotating or spiral movements on shafts, spindles, rotary transmission leadthroughs, etc.

Fluorezi® O-Rings

Fluorezi® is a member of the perfluoroelastomer family. Perfluoroelastomers are terpolymers of monomers in which all hydrogen atoms have been replaced by fluorine. The absence of hydrogen in the molecular chain dramatically increases both the chemical and thermal resistance of perfluoroelastomers. The cross-linked molecular chains enable perfluoroelastomers to combine the resilience and sealing force of an elastomer with the chemical inertness and thermal stability of PTFE. The range of Fluorezi® perfluoroelastomer compounds developed by our specialists offers exceptional chemical resistance over a wide range of temperatures from -25 °C up to +320 °C.

The Fluorezi® combination of high performance and quality with state-of-the-art sealing design provides a wide range of customer advantages:

• superior reliability, cutting planned and unplanned maintenance costs;
• longer service life, reducing costs and driving up productivity;
• greater safety and reliability, reducing waste and contamination;
• more opportunities for standardization and inventory reduction;
• optimized seal solutions cutting the risk of failure.

Fluorezi® perfluoroelastomer sealing products bring all these benefits to a wide range of applications for equipment manufacturers and end users in many industries like:

• chemical processing;
• pharmaceutical and food industries;
• oil & gas;
• hydrocarbon processing;
• semiconductor and nanotechnology;
• lacquer, print and coatings;
• aerospace;
• power generation.

FEP (Encapsulated) O-Rings

Encapsulated O-Rings consist of an elastomer inner ring and a seamless sheath which surrounds the elastomer ring. Similar to PTFE O-Rings encapsulated O-Rings are used wherever the chemical resistance of normal elastomer O-Rings are not sufficient. The required elasticity is provided by the elastomer ring, the chemical resistance by the seamless sheath.

Advantages of encapsulated O-Rings:

• chemically resistant;
• wide range of thermal stability;
• low permeability;
• low friction.

The encapsulated O-Rings are available in the following materials:

• encapsulated FEP/FKM;
• encapsulated FEP/VMQ;
• encapsulated PFA/FKM;
• encapsulated PFA/VMQ.

Hollow O-Rings

Hollow O-Rings offer a low closure force alternative to solid O-Rings. As required for many lids and doors, hollow O-Rings are used in applications that require the seal to stay in the groove while not overfilling the gland or warping the enclosure lid or door.

X-Rings are four lipped seals with a specially developed sealing profile. A wide range of elastomer materials for both standard and special applications allows practically all liquid and gaseous media to be sealed. X-Rings are vulcanized as a continuous ring. They are characterized by their annular form with a four lipped profile. X-Rings are supplied in dependence on the AS 568 B and BS 1806 standard.

In contrast to the O-Ring, an X-Ring has the following advantages:

• avoids twisting in the groove. Due to its special profile, the seal does not tend to roll in the groove during reciprocating movement;
• low friction;
• very good sealing efficiency. Due to an improved pressure profile over the X-Ring cross-section, a high sealing effect is achieved;
• a lubricant reservoir formed between the sealing lips improves start up;
• unlike an O-Ring, the mould line flash lies in the trough, between and away from the critical sealing lips.

X-Rings can be used for a wide range of different applications. X-Rings are used predominantly for dynamic sealing functions. It's use is always limited by the pressure to be sealed and the velocity.

Dynamic applications:

• for sealing of reciprocating pistons, rods, plungers, etc;
• for sealing oscillating, rotating or spiral movements on shafts, spindles, rotary transmission leadthroughs, etc.

Static applications:

• as a radial-static seal, e.g. for bushings, covers, pipes, etc;
• as an axial-static seal, e.g. for flanges, plates, caps, etc;
• as an energizer element for elastomer energized hydraulic seals where there is a risk of the O-Ring twisting.

The Square Ring is a good alternative to the O-Ring as an axial static seal in cases where particular demands are made. The application and handling of Square Rings is comparable with those of O-Rings. The Square Ring is used as a static seal so that the square form remains practically constant even under high pressures.

Advantages of Square Rings:

• high resistance to extrusion, not sensitive to gap extrusion;
• minimum mechanical deformation of the cross-section;
• outstanding sealing behaviour over long periods;
• good compression set;
• no twisting in the groove;
• no relative movements during pressure cycles;
• dimensionally stable under pressure;
• no additional Back-Up Ring required;
• no parting line or flash on the seal;
• long service life;
• high leak tightness.

Many applications are:

• flanges;
• valves;
• plates;
• locks.

Back-Up Rings are used for static and dynamic applications in connection with O-Rings, to prevent extrusion of the O-Ring into the diametrical clearance.

We recommend to specify Back-Up Rings when at least one of the following working conditions is present in cases where the intention is to seal with O-Rings only:

• pressure above 50 bar;
• diametrical clearance exceeding 0,25 mm at p > 10 bar;
• high stroke frequency;
• high temperatures;
• contaminated medium;
• strong pressure pulsing or pressure changes.

Wiper rings are used to protect seals, preventing contamination from dirt particles (dust, mud, water, etc.). The lip of the wiper removes even the first dirt from the piston rod. Such dirt particles can cause damage to hydraulic or pneumatic systems during stroke movement. Even if they appear in good condition, wipers should always be replaced when changing seals.

Many applications are:

• earth moving equipments;
• lift trucks;
• hydraulic presses.

The V-Ring is an elastomer axial seal for shafts and bearings. It seals axially against a counterface. This type of seal has been used widely for several applications and has proved to be reliable and effective against dust, dirt, water and oil splash and other media.

The ring consists of three parts:

• the seal body, installed with interference to the shaft;
• the hinge, acting as a sprung connection between the body and the lip;
• the conical self adjusting hp which provides the actual dynamic sealing against the counterface.

The counterface can be the outside of the bearing cap, a washer or any suitable metal pressing.

Oil Seals or Rotary shaft lip seals are components designed in a ring form, fitted between machine parts in relative rotation, with the function of separating oil or grease from the inside and dirt, dust, water etc. from the outside. The rotary shaft seals are generally composed by an elastomeric diaphragm, shaped in a "lip form" and reinforced with a co-vulcanized metal insert. The sealing lip is usually energized with a "Garter Spring".

Many applications are:

• transmission systems (e.g. gearboxes);
• pumps;
• electrical motors;
• machinery industry (e.g. tool machines);
• heavy engineering applications.