DAEJUNG’s high performance butterfly valve was introduced in 1987. The MAX-SEAL valves is the result of experience in the design and manufacture of control and butterfly valves are leak tested per MSS-SP61 & API 598 standards, and tagged per MSS-SP25 & API 609B specifications. 

DAEJUNGMAX-SEAL A-Series High Performance Butterfly Valves, serving Multi-National end users in a wide range of applications in many industries including:

1. Chemical & Petrochemical                    7. Oil refinery industries

2. Power generation plants                       8. Desalination industries

3. Ship building industries                         9. Steel & Iron industries

4. Fiber industries                                     10. Pulp & Paper industries

5. Food industries                                     11. Coal & Mining industries

6. LNG, HRSG industries                          12. High Presure HVAC applications

Eccentric Double Offset Design Seating

The double offset shaft/disc design ensures bi-directional sealing throughout the full pressure range of the valve. The cam-like action produced by the offset stem and disc, effectively lifts the disc off the seat during the initial opening of the valves, reducing seat wear and eliminating seat deformation at the top and bottom. When the disc is in the open position, there is no contact between the disc and seat. Operating torques are reduced and seat life is extended.

Soft Seat Material Maximum Working Temperature

PTFE-SEAT 190°C (375°F) TFM-SEAT 246°C (475°F)

RTFE-SEAT 230°C (446°F) PEEK-SEAT 270°C (529°F)

Metal Seat High Performance Butterfly Valve

Seat Material Maximum Working Temperature

METAL-SEAT 315°C (600°F)

Class V of ANSI / FCI 70-2 Class V leakage rate

Fire Safe Seat High Performance Butterfly Valve

Seat Material Maximum Working Temperature

SS316L*RTFE 230°C (446°F)

FIRE-SAFE to API 607 5^th Edition

SEAT LEAKAGE- Leakage of soft seated version is ZERO

Vacuum Service

The drop tight sealing capabilities of MAX-SEAL valve are excellent for vacuum service. Soft seated standard Valves are suitable for vacuum service to 20 microns. Denote vacuum service on the order.

Steam Service

MAX-SEAL standard valves are ideally suited for saturated stem applications to 180°C (135psig)(RTFE seat). Carbon filled TFM seats and high temperature graphite stem packing can handle pressure up to 195°C (200psig)

Product Identification

Every Max-Seal Valve has a special identification tag attached to the valve body. Information includes valve figure number, the size and pressure class, the materials of construction, and the operating pressures and temperatures.

The metal tag also includes a serial number: The serial number is recorded by the DaeJung Quality Control Department along with the test results and material certification data, for individual traceability and certification of every valve produced.

Dead End Service

MAX-SEAL, lug bodies for dead-end service are offered as standard in full ANSI Class 150 and 300.

Standard Specifications

Body Style: Wafer, Lug

Valve Size: 3/4” – 48” (20~1200mm)

Rating: ANSI Class150, ANSI Class 300

Applicable Flange Standard: ANSI B16.5

Face to Face Dimensions: API 609, MSS SP68, ISO5752

Actuator Mounting Flange: ISO 5211

Valve Design: MSS SP-68

Valve Design: API 609

Valve Design: ANSI B16.34

Valve Testing: API 598 Inspection and testing

Valve Testing: MSS SP-61 Testing of Steel Valves

Valve Marking: MSS SP-25

Valve Material: NACE MR-01-75

Valve to Official API Monogram

Valve to API Specification Q1

Valve to API ISO 9001:2000

Valve to ISO/TS 29001

Valve to API 609

A Wider selection of higher pressure & sizes reaching up to 120 inch, ANSI Class 600 is available on a special order basis.

Every Valve is Strength Tested

Shell tested to 150% of rated pressure with the disc open… hydro-static seat tested for bi-directional positive shutoff without leakage at 110% of rated pressure. We also test for absence of leakage into valve shaft bearing areas. Only valves meeting a positive shut-off standard are approved for shipment.