Frenstar Valves

Triple Offset Butterfly Valves

The triple offset high performance butterfly valve, has three offsets from the centre. The third offset is the elliptical seat geometry. This along with the two eccentric shaft offsets, allows the disc to seal against the seat with no friction.

This seat design allows for uniform sealing, and thus bi-directional tightness at maximum differential pressure.

This triple eccentric design is a lower cost, lower torque option than alternative style metal seated valves. It is low maintenance and offers an extended valve life.

The triple offset butterfly valve is used in critical demanding applications in:

  1. Oil & Gas (Offshore FPSO, fixed platforms and LNG carriers)
  2. Oil & Gas (Onshore Refinery, storage and distribution)
  3. Petrochemical
  4. Power Generation
  5. Process & Chemicals
  6. Water & Wastewater Treatment
  7. Marine
frenstar triple offset butterfly valve DF-TML
frenstar triple off set butterfly valve Solid type metal seat
Solid type metal seat
frenstar triple off set butterfly valve Graphite laminated seat
Graphite laminated seat
Specifications
Description
BUTTERFLY VALVE High Performance Triple Offset Metal Seated Fire Safe Cryogenic also available
Design Code
API 609 / EN593
Size Range
NPS 3” – 96” / DN 80-2400
Maximum Pressure /Rating
150# to 1500#
Design Temperature
-196°C to +600°C (MOC Dependant)
End Connections
Wafer / Lug / Double Flanged / Butt-Weld
Body Seat
Metal + GRAPHITE
Solid Metal
Seat Leakage
Bi-Directional Bubble Tight Shutoff (CL.150 ~ 600)
Uni-Directional Bubble Tight Shutoff (CL.900 ~1500)
Materials of Construction
Body
Carbon Steels inc. Low Temp
Austenitic/ Super Austenitic Stainless steels
Aluminium bronze
Duplex/ Super Duplex alloys (1A-6A)
Titanium
Hastelloy® B, C, Inconel
Monel®, Alloy 20
Others upon request
Shaft
AISI 410, AISI316, 17-4Ph, Monel® K500, UNS32760, Titanium
Seat
SS304 / SS316 / SS316L / Inconel / Titanium
Hard-facing
Stellite Gr. 6 / Gr.21 / 13% Cr. Weld Overlay

Frequently Asked Questions

A Butterfly valve is a quarter-turn rotary motion valve with advantage of low pressure drop and high-pressure recovery.

Butterfly valves are used to stop, start, and regulate fluid flow.

Concentric butterfly valves also known as ‘resilient seated’ butterfly valves are suitable for a wide range of applications such as cooling water, chemicals, brine,oil mud, hydrocarbons, wastewater, firewater, seawater, natural gas and flare gas amongst many others. The stem is centred in the middle of the disc and the disc centred in the valve body. The disc is constantly in contact with valve seat. Seats can include EPDM, NBR, Viton, Silicon, Teflon, Hypalon and neoprene.

A high performance butterfly valve. This valve has three offsets from the centre. The third offset is the elliptical seat geometry. This along with the two eccentric shaft offsets, allows the disc to seal against the seat with no friction. This seat design allows for uniform sealing, and thus bi-directional tightness at maximum differential pressure.

The triple offset design is used where bubble tight shut-off, zero leakage is required in common applications such as steam, chemical, refining, and offshore oil and gas. They offer a lower cost, lower torque option, than alternative style metal seated valves. It is low maintenance and offers an extended valve life.

double offset butterfly valve is a high performance butterfly valve. This valve has two stems offset from the centre. It is capable of providing accurate, stable, throttle flow control.

Butterfly valves can be bi-directional but often have a preferred flow direction. It’s strongly recommended to install the valves in the preferred flow direction, as it will extend the valve’s life span and will also lower the operating torque. High-performance butterfly valves for hydrocarbon service generally do not have a preferred flow direction and are bi-directional.

Yes, Triple Offset Butterfly valves can be used for isolation. Triple Offset is a great alternative to the block valve incumbents like gate. If gate was not applicable to process conditions ball valves were utilized.

Triple Offset Butterfly valves have the following but not limited to advantages in this application;

  • Cost effective
  • Ease of operation
  • More readily available than other valve offering 

Motor Operated Valve (MOV) are often called On-Off valves as the motors act to fully open or fully close valves in pipelines. With regards Butterfly valves they fully open or fully close the disc with tight shut off as per plant requirement.

The lugged wafer design, butterfly valve is held in place between two pipe flanges by bolts that join the two flanges and pass through threaded holes (or lugs) in the valve’s body.  This design type can be used for dead-end service.

The wafer type butterfly valve, also known as non-lugged is sandwiched between two pipeline flanges.  It may sometimes have unthreaded guiding holes for ease of installation.

Flange type or Double Flanged Butterfly valves have two flanges – one either end as opposed to lug type which has one flange in the centre. Flange type have a larger face to face than wafer or lugged. These can be used for dead end service.

This can depend on butterfly valve type installing – contact Frenstar for assistance with installation or to request Installation, Operation and maintenance manuals.

Butterfly valves can be used in throttling / flow control, or on-off control. High performance butterfly valves are widely used for throttling control.