Pressurized external barrier liquid system supplying clean fluid to the inboard and outboard seal faces.
![API Plan 54](/wp-content/uploads/API_Plan-54.png)
Description
Plan 54 involves the circulation of clean pressurized barrier fluid sourced from an external system. It is used in Arrangement 3 seals where barrier liquid pressures should remain at 20 psi or higher.
Application Notes
- Used with Arrangement 3 seals.
- Cool, clean product from an external source is supplied to the seal as a barrier liquid.
- Barrier liquid is maintained at a pressure greater than the seal chamber pressure.
- Barrier liquid pressure should always exceed the maximum seal chamber pressure by at least 20 psi [1.4 bar].
- Barrier liquid is circulated by an external pump.
- Process fluid never leaks to the atmosphere unless system pressure is lost.
- Superior management of seal generated heat due to higher flow rates than that of Plans 53A, 53B, and 53C.
- Provides barrier liquid cooling and circulation even if the process pump is not active.
- Sensors and flowmeters may be added within the external system to readily identify seal failure based on support system conditions.
- Barrier liquid must be compatible with the process liquid because it will leak into the product.
- If used on multiple seal installations, failure of one installation can affect all of the other installations unless proper precautions are taken to isolate the failed seal.
Pros:
- Provision of pressurized flow to multiple seals within one system
- No risk of process fluid leakage at proper system pressures
- Barrier fluids provide superior cooling
Cons:
- Barrier fluid and process fluids must be compatible due to the possibility of mixing
- Complex system with higher maintenance