The philosophy of FAI design is not only limited to complying with the code but it also focuses on the fatigue life of the closure assembly and its components, including the gasket. It is a well-known fact that to reduce the stress in the closure components, it is common practice to minimize the elastic deformation. FAI has evaluated the distribution and localization of the stresses in each component.
Based on FAI’s knowledge and regardless the specified steel grade, the stress parameters assumed in the calculation are significantly below the allowable limit and, as a result, each component is effectively redundant. This approach enables FAI design to have a sturdy construction, suitable to properly withstand any unforeseen peaks of stress.
As standard feature, the FAI “Bayonet” End Closure is spark proof and vacuum duty.
In addition, through an implementation of minor modification, the FAI end closures suit different services such as:
- Fire safe
- Gas Sealing (cyclic gas service)
- Cryogenic service
- Fatigue life (FAI quick closure is granted for 30,000 cycles from zero to design pressure)
To demonstrate the suitability to withstand these services, dedicated tests have been developed in house under Third Party supervision for certification purposes, while capability tests are always available for:
- Pneumatic cyclic gas leaking test by nitrogen or helium up to 430 barg
- Hydrotest in cooled box under cryogenic condition
- Cyclic pressure test (continuous recorded) to simulate fatigue test over 30,000 cycles (from 0 to 250 barg) for quick closure working in dyeing sector.
Additional instrumentation can be designed and supplied in support of the closure:
- key interlock
- proximity switch
- control system
When required or due to heavy sizes, operation may be assisted and supported by:
- hydraulic or electrical opening/closing
- mobile pneumatic tool
Additional Safety Features
The FAI “Clamp” End Closure is also designed to ensure that, after the system depressurization and the safety device open, the possible presence of liquid static head cannot cause any undesirable door slam.
The seal in the FAI “Clamp” End Closure is face-to-face type (door & hub not diametral), therefore the pre-asset of the Gasket is completely nullified after the first turn of the tie rod, as the door hub teeth is conical.
As a consequence the minimal opening loosens the seal and the liquid, if any, is free to drop through the drain hole located in the bottom segment of the clamp, giving a warning signal to the operator.
At this stage the door is still engaged in the clamp and cannot slam. Any additional monitoring device can be provided upon request.
FAI’s care in the design of the end closure looks at the ENVIRONMENT where the closure is generally working.
FAI’s engineers are skilled and have direct field experiences in Onshore, Offshore, Deserts environments at every latitude. This experience is transferred to the FAI “Clamp” End Closure, designed with the aim of minimizing maintenance and make all operations easy under any condition/circumstance.
This is also evident looking at the choice of the materials extensively used (stainless, duplex, aluminum bronze, alloy 625, etc…) to reduce the atmospheric corrosion. This, in a few words, is the reason why the lifetime of the FAI “Clamp” End Closure is more than thirty-five years.