Type A

Pusher seal
Balanced
Cartridge design
With multiple springs
Rotating type
O-rings as secondary sealing

Type B & C

Non-pusher (metal bellows)
Balanced
Cartridge design
Rotating type for Type B
Stationary type for Type C

API 682 Standard
Arrangement 1 - Single Seal
Arrangement 2 - Unpressurized Dual (Tandem)
Arrangement 3 - Pressurized Dual (Double)

Our API 682 Test Equipments
Nippon Pillar has every API682 4th Edition Test Bench.

*LPG Test Bench
Nippon Pillar API682 4th Edition Certificate (example)