ENERGISED SEALS

Thanks to the use of durable materials and state-of-the-art technology, our seals can be produced to design according to different technical requirements. The wide range of solutions in our catalogue features a structure consisting of a polymer sleeve and a corrosion-resistant metal spring.

The energised seal concept

The way the seal functions is quite simple. There is an external component called sleeve, usually in fluorinated polymer, which corresponds to the seal, and an internal spring that makes the system elastic.

Once the seal is mounted in its seat, the spring is compressed due to the interaction of the seal with the groove, thus exerting a force which, along with that generated by the system under pressure, ensures that the seal holds.

ANALYSIS OF FINITE ELEMENTS

The analysis and study of the Finite Elements helps us better understand what the basic concepts of the seal hold are and what parts of the seal are more likely than others to yield under pressure. Below is an example of a seal fi tted in a groove where the dynamics of the compression (in this case, minimal) of the spring can be clearly seen, and the virtual absence of sleeve deformation.

1-energised-seals-for-axial-and-radial-systems

Fig.2 – Initial deflection of the seal

Fig. 3 – Modification of the contact areas under internal pressure

At this point the system subject to pressure exerts a force that deforms the seal, modifying the contact surface with the seat.

Fig. 4 – Evolution of contact pressures with the increase of internal pressure

The relationship between internal pressure and the pressure exerted by the seal for the hold is shown in the diagram below.

CLASSIFICATION

Energised seals are divided into two main types, Radial and Axial, and into Static and Dynamic. During the design phase, checking the operating conditions, the appropriate spring for that application is used from among the ‘Toroidal’ ‘Comb’ or ‘V’ springs commonly known as Raco®.

All springs differ in material and load, which is why careful design is fundamental for the correct functioning of the energised seal; neglecting this important operation leads to products that are not suitable for use with serious repercussions for the end customer.

For easy identification we have divided the seals into ‘Series’ each representing different combinations of type, materials, springs and use and summarising a large part of our production; outside of the combinations presented below we produce other profiles and seals identified according to our specific drawings.