Mubea Disc Springs and the Subsea Industry

Outstanding performance and reliability

Mubea Disc Springs is the world number one in the development and manufacture of disc spring stacks as well as a multitude of other highly engineered components used in many industry sectors including the subsea industry.

The energy sector uses Mubea spring stacks everywhere from drilling tools to the tip of the flare stacks but one significant success story is their use in subsea valve actuators.

The advantages that Mubea disc spring stacks offer have been utilized successfully in the oil industry for three decades and at the beginning of the 21st century the subsea sector embraced the concept for the first time. By using disc springs in their subsea actuators a leading subsea contractor was able to offer benefits that none of its’ competitors were able to do. The primary benefit was the amount of space the disc spring stack required in comparison to the coil spring that would be required to do the same job.

This compact design offers many advantages to operating companies in the subsea industry in terms of weight and the space requirements for a complete subsea tree as each tree may have as many as seven actuators.

The transition from traditional coil springs to disc spring stacks was not an overnight event. The engineering teams from Mubea and the subsea firm spent several years in perfecting a series of large disc spring stacks that use an innovative wire-centering method to allow for use in the horizontal plane without any form of guidance. This meant that the actuator could be built with varying internal diameters and very little contact with the Mubea springs.

The prototype springs were tested by Mubea in purpose built horizontal fixtures that exactly replicated subsea conditions. Mubea constructed “cans” that were identical to the customer design and then created a system that used the same control fluid as in the field. The industry standard for faultless valve operation was met and surpassed before prototypes were supplied to the customer for their own in-house testing as well as third party verification. Fatigue life testing on some of these spring stacks were terminated simply because the springs had been cycled far more times than required by the industry standard and yet were still performing to the requirements of the customer.

This longevity of performance can be attributed to the robust design of the disc springs and the level of quality management that Mubea exercises throughout the manufacturing processes. From raw material supply to assembly and testing of the completed disc spring stack Mubea has complete control. The base material for Mubea springs is chrome vanadium spring steel. This is the same material that many other spring manufactures use to produce all types of springs. It is the same material used for the coil springs that the disc springs replaced however the degree of expertise employed by Mubea ensures that physical defects are non-existent. The superior manufacturing processes also ensure that problems such as hydrogen embrittlement cannot be an issue with these highly-sophisticated spring stacks when they are delivered to the Mubea customer.

In conclusion, the advantages of using Mubea are:

• – Unsurpassed quality
• – Superior manufacturing process
• – Highly engineered products
• – Unmatched record of accomplishments

And the advantages of using Mubea disc springs for subsea application are:

• – Robust design
• – Accuracy in meeting requirements of force and travel
• – Reduced equipment footprint possible
• – Custom built springs to exactly meet the most stringent requirements.