The Linuo butterfly is a quarter-turn valve suitable for both on/off and throttling service. The
triple offset design offers torque seating for tight shut off and minimal friction. Where
traditional butterfly valve discs are in contact with the seat throughout the first 10 degrees of
opening, the triple offset means that as soon as the valve begins to open, the disc surface
moves away from the seat. Less friction means not only less wear, but also less torque, and
longer life. Linuo valves are used extensively in industries such as pulp and paper, chemical
processing, petroleum, chemical fiber, powder processing, pharmaceutical, and environmental
Butterfly valves by their nature have a small face-to-face dimension and are much lighter in
weight than equivalent service ball valves. Less metal means butterfly valves are a much more
economical option than ball valves.
SEAL DESIGN OPTIONS
Various seat seal designs are available: resilient metal seal, laminated metal seal, and PTFE
seal. The type of seal to be selected is dependent on the specific process and shut off
The upper and lower shafts are held by double bearings that provide excellent stability and low
torque. Bearings are made of a composite plastic material that is sintered on the loading
surfaces to make them abrasion resistant and improve the self-lubricating aspect.
The disc of the triple-offset design butterfly valve is torqued into the seat. This is a significant
advantage over standard butterfly valves where the disc can spin 360º, and seating only takes
place when the disc is perfectly aligned with the body seat centerline. The torque in seat of the
Linuo means tight shutoff is easily achieved, even at low differential pressures or with reverse
FIRST OFFSET: Shaft centerline is offset from that of
the valve and the pipe.
SECOND OFFSET: Shaft is offset behind the disc face.
THIRD OFFSET: Disc sealing surface of the disc is
offset in the shape of an oblique cone.
The first and second offsets, ensure that at the moment of the
valve opening, the disc is instantly removed from contact with
the body seating surface. Without contact at that point,
abrasion and torque are low. The third offset means that the
disc sealing surface is similar to an oblique slice taken out of
a metal cone. This produces a separation angle between the
tangent of the disc motion curve and the body sealing
surface. It enables uniform pressure sealing around the
entire sealing surface, for the best shutoff.
Sizes: 2" through 48"
Pressure Class: ANSI 150 and ANSI 300
End Connections: Lug, Wafer, or Flanged
Temperature Range: For soft seat: -4ºF to 320ºF,
For metal seat: -4ºF to as high as 800ºF
Face-to-face Dimensions: Per GB/T12221
Leakage: For soft seat: zero leakage,
For metal seat: Class V
Pressure Testing: Each Linuo valve undergoes
Hydraulic testing with 1/5 X pressure rating for the
shell test, and 1.1 X pressure rating for the seat
tightness test. Testing medium is water.
Flow Characteristic: Approximately equal percentage.
NOTE: ZSQ and ZDQ series actuators are developed and manufactured by Linuo. For actuator particulars, please refer to the
Z Series Piston Actuator Catalog or consult Linuo. The actuators above are recommended for Class 150 valves with process
pressure of 232 psi and normal temperature, with a minimum air supply pressure of 72 psi. For actuator selection for
operation at different process conditions, consult Linuo.