Bray – Tri Lok Triple Offset Butterfly Valve

Code: Tri Lok

Bray proudly offers the Tri Lok triple offset butterfly valve, a premier isolation valve well-suited for operation in light vacuum to high-pressure applications and ideally suited for applications requiring absolute zero leakage. Compared to gate, globe or ball valves of the same size and pressure class, Tri Lok provides space and weight savings while minimizing installation and maintenance costs.

Tri Lok’s, non-rubbing, metal-to-metal seal delivers zero leakage with minimal torque and is certified fire-safe. The resiliency of the seal ring ensures uniform peripheral sealing with the seat, achieving full shutoff regardless of flow direction. Tri Lok offers a solid metal seal ring for high-temperature and severe service applications to ensure bi-directional shutoff throughout the full pressure/temperature range.

Bray Tri Lok is the only valve in its class with a splined disc/stem connection. The Tri Lok connection allows axial movement of the disc independent of the stem, keeping the seal ring and seat in position and unaffected by temperature fluctuations and pressure effects on the stem. This design prevents the typical misalignment problems of rigidly attached discs and stems to offer maximum strength. Close tolerance engagement between the disc and stem minimizes hysteresis.


Triple Offset Geometry

The Triple offset valve or triple eccentric valve features a stem that is offset on both the X (1) and Y (2) axis of the butterfly valves center-line. This produces a cam-like motion as the valve operates. The third offset (3) consists of an inclined conical profile machined into the valve sealing surface, allowing rotary engagement and disengagement of the seat and seal ring without interference. This triple offset eliminates all rubbing between the seat and seal ring during valve travel, reducing seat and seal wear and extending cycle life.

Once the seat and seal ring are fully engaged, torque is applied in order to create a bi-directional, zero leak, metal-to-metal seal. For this reason, triple offset valves are often defined as “torque-seated” rather than “position-seated” as in the case of resilient or high-performance products.

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Bray – Tri Lok Datasheet
Bray – Tri Lok Technical Datasheet
Bray – Tri Lok Manual

Technical specifications

Size Range

3" – 48” (DN80 – DN1200)
Larger sizes available upon request

Body Materials

Carbon Steel, Stainless Steel
Other Materials Upon Request

Maximum Allowable Operating Pressure

ASME Class 150, 300, 600, 900
PN10 - PN720

Stem Materials

17-4PH, 410 Stainless Steel, & XM-19 (Nitronic 50)

Seat Materials

316 Stainless Steel Hardened

Shutoff Rating

Zero Leakage

Disc Materials

Carbon Steel, Stainless Steel
Other Materials Upon Request

Body Style

Lug, Double Flanged, Wafer, and Gate

Design Standard

API 609, B16.34

Flange Drilling

ASME B16.5, B16.47, ISO 7005

Testing Standard

API 598 (Soft Seat), API 6D, ISO 5208


API 607, ISO 10497, ISO 15848-1, API 641, TA Luft, CRN, ABS, GOST, PED, SIL, TSG

Face to Face

API 609, ASME B16.10, ISO 5752, EN 558

Fugitive Emissions

ISO 15848-1, API 641, TA Luft


Bulk liquid storage, oil & gas, LNG storage & transportation, steam distribution systems, power generation, geothermal steam, sugar & ethanol, pulp & paper liquor, refining, chemical processing, water & wastewater, air separation, cryogenic services

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