API 682 Plan 21 is a standard flushing plan for mechanical seal systems. Its primary function is to provide cooling to the seal chamber using an external heat exchanger.

Working Principle
High-temperature process fluid from the pump discharge enters the shell side of the heat exchanger, while cooling water flows through the tube side to remove heat. The cooled fluid is then returned to the seal chamber, continuously carrying away the heat generated by seal friction.

Three Key Engineering Points
Independent support: The Plan 21 heat exchanger must be mounted on its own support structure and must not be attached directly to the seal gland.
Water quality control: Cooling water scale significantly reduces heat transfer efficiency and is a common cause of seal failure.
Typical application: Suitable for single cartridge mechanical seals under high-temperature service conditions.

Value Proposition
With proper design, selection, and maintenance, a Plan 21 system can extend mechanical seal life by more than three times.

Need a Plan 21 selection checklist or technical datasheet? Please leave a comment or contact us via the official website.

Dandong Runhe Seal Co.,Ltd.
Add：No.70-43, Wenqing Road, Instrument and Apparatus Park, Dandong, Liaoning, China.
Tel.：86-415-5711666
Mob: 0086-18541507008
Email：export@rhseal.com
Wechat ID: RunheSeal
Web：www.rhseal.com  

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