Quench stream is brought from an external source to the atmospheric side of the seal.
![API Plan 62](/wp-content/uploads/API_Plan-62.png)
Description
This plan can be used to enhance the environment on the exposed side of single seals by quenching using steam.
Application Notes
- Quench is used to prevent unwanted material buildup on the atmospheric side of the seal faces.
- Must be used with a close clearance bushing or containment device in the seal gland to concentrate the quench to the desired target area.
- Quench pressure should be maintained between 2 to 7 psi [0.14 to 0.48 bar] to ensure purging of atmospheric gases.
- Often used with steam to avoid coking or crystallization in hot hydrocarbon services. Often used with nitrogen to avoid icing in cryogenic applications.
- Low-cost alternative to double seals to improve conditions on low-pressure side of process seal.
- Bushing contains the quench in the seal gland and also provides protection for personnel if a high temperature quench is being used.
- Proper controls must be in place to ensure steam does not condense and then boil, which could cause seal damage on hot processes.
Pros:
- Provides a low-cost substitute for tandem seals
- Quenching prevents coking and offers some degree of cooling
- Effective in both vertical and horizontal pumps
Cons:
- Leakage will lead to loss of pumped fluid to the exterior