Pump rings are elements that ensure the correct operation of a mechanical seal exposed to high temperatures.

Temperature is a key factor to consider in the operation of sealing solutions.

Depending on the temperature range in which our system operates, we must choose different designs of mechanical seals and different types of materials for their components.

If you want to know more about how do high temperatures affect mechanical seals and how can pumping rings be helpful, watch out for this article.

High temperature effects on mechanical seals

Applications that require working with substances at high temperatures are very common in the industrial sector.

High temperatures have a direct effect on the elements that make up a mechanical seal. Among the elements affected by a high temperature, we find secondary joints such as O-rings, these being the most sensitive to temperature.

When choosing the right O-ring for mechanical seals operating at high temperatures, we must choose resistant materials.

For example, EPDM, EPDM Peroxide or Aflas®‍ are the most suitable materials for hot water or water-based solutions up to temperatures that can reach 170 ºC.

For temperatures with fluids such as mineral oils, joints made of FKM or FFKM can withstand temperatures up to 200 ºC.

But high process temperatures not only affect the joints of a mechanical seal, another of the affected elements are the seal faces.

If the process fluids are at a temperature close to evaporation, it is very likely that when they come into contact with the mechanical seal they acquire the necessary temperature, to evaporate prematurely between the faces of the seal.

This phenomenon would cause the mechanical seal to work dry and, consequently, if it is not prepared for it, it would end up damaging it.

Finally, we must not forget that metal components are also affected by high temperatures. Metal elements such as springs, when exposed to high temperatures, may deform and end up not exerting the proper force for the proper functioning of the mechanical seal.

Pumping rings as auxiliary systems in mechanical seals

Very often the process temperature of a mechanical seal is high. For this reason, solutions have been designed to solve the problems associated with higher temperatures than usual in mechanical seals.

These solutions involve the integration of an element that increases the thermal dissipation capacity ensuring the proper operation of the mechanical seal. An example would be a pressurized secondary cooling circuit.

We have to consider that not only the heat of the process is the responsible of the temperature, but also the following effects influence:

• The normal operation of the mechanical seal generates an increase of the temperature, due to the friction between the faces.
• The rotational speed of the system can generate more temperature than normal.

At the same time, if the general temperature (the process one and the temperature generated by the seal itself) is very high, the secondary cooling system may not have enough heat dissipation capacity.

In this case, to solve this problem, the secondary fluid flow through the seal must be increased to increase the dissipation power.

To do this, auxiliary pumping systems are ensambled but these systems are complex and, if the secondary fluid needs to be pressurized, expensive.

This is where the pumping rings come into play. The pumping rings are integrated into the mechanical seal housing or into the cartridge sleeve.

Lidering has mechanical seals with pumping rings

In Lidering we have different types of mechanical seals with mechanized pumping rings integrated in the metal housing.

Thus they help to pump the barrier fluid through the pump chamber where they are installed.

As an example, the LDC40 cartridge model has a volumetric pumping system that allows an increase in flow even at low revolutions, thus increasing the thermal capacity of the seal.

But we don’t just have standard solutions. Thanks to our Production Center, we can design, manufacture, upgrade, repair and integrate special custom designed pumping rings to meet application requirements.

If you want to increase the performance and shelf life of your mechanical seal, consider adding a pumping ring.

We hope you have found useful this article on how high temperatures affect mechanical seals and how pumping rings are a simple and economical solution.

If you still have any questions, please contact our sealing solutions engineers team.

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