In industrial agitator applications, one of the biggest sealing challenges is to ensure lubrication when the product does not come into contact with the mechanical seal.
As we told you in the post on Manufacturing high performance mechanical seals for reactors, this often occurs in reactors or vessels where the process fluid is in the lower part of the system.
In this dry working condition, it is essential to have a double mechanical seal to ensure reliable and durable operation.
At Lidering, we have developed the LDC40 double cartridge mechanical seal, a technical solution specifically designed for the demands of the MRO industry, capable of adapting to the most demanding speed, temperature and sealing conditions.
Why choosing a double mechanical seal for agitators?
In industrial agitators, simple sealing is often insufficient. The absence of lubricating fluid between the friction faces can lead to premature wear, seal failure and overheating. This is where the LDC40 cartridge, with its double mechanical seal design, makes the difference.
This cartridge works with a secondary fluid (barrier fluid), i.e. a liquid that is introduced between the two seal faces and acts as a lubricating and cooling element.
This technical solution allows:
- Work with corrosive, abrasive products or products with risk of crystallisation.
- To increase the service life of the sealing system.
- Dissipate heat generated by internal friction.
- To ensure sealing even in processes with variable pressure or high rotations.
Double mechanical seal performance: reliability under extreme conditions
The LDC40 has the ability to operate at elevated temperatures. It is enhanced by an integrated pumping system, which drives the barrier fluid through the internal chamber of the cartridge. This continuous flow ensures proper heat dissipation, keeping the seal environment stable even over extended production cycles.
Barrier fluid supply for MRO agitators: open or closed
The barrier fluid in the LDC40 cartridge can be supplied in two configurations:
- By open circuit, using mains water or other external source.
- By closed circuit, using a pressurised tank such as the Lidering LST9, designed to maintain the barrier fluid at optimum pressure and temperature.
To ensure lubrication between faces, it is advisable that the barrier fluid has a pressure slightly higher than that inside the agitator, ideally between 1 and 2 bar above. This principle is in line with the API Plan 53A concept, which establishes a controlled barrier flow to prevent product from entering the seal chamber.
Technical aspects of the double mechanical seal: purging and filling of the cartridge
One of the critical points in double seal systems is to ensure that no air pockets are left in the barrier fluid chamber. The LDC40 cartridge incorporates an integrated venting system that facilitates this operation easily and safely.
A small hole in the flange of the cartridge gives access to a metal part which, when moved slightly downwards (approx. 1 mm), allows the air to escape and the chamber to be completely filled with barrier fluid. This operation is quick and effective, and guarantees the correct functioning of the cartridge from the moment it is put into operation.
Main features and benefits of the LDC40 cartridge
- Double mechanical seal with integrated barrier fluid.
- Safe operation in dry working conditions.
- High resistance to variable temperatures and pressures.
- Linear operating speeds up to 16 m/s.
- Internal pumping system for improved cooling.
- Compatible with open and closed circuits (LST9).
- Easy purging and start-up with filling system.
Who is the LDC40 dual cartridge seal intended for?
This cartridge has been designed with industrial maintenance departments (MRO), process engineering and machine builders in mind who need a reliable sealing solution for their agitation equipment.
So, if you work with industrial agitators and you are looking for a durable and efficient sealing solution, at Lidering we design and manufacture cartridges such as the LDC40, adapted to the requirements of your production process. Contact our technical team and find out how to improve the sealing and performance of your installation.
