Butterfly valves are quarter-turn flow control devices that utilize a metal disc that rotates around a fixed stem axis. They are fast-acting flow control valves that allow 90 degrees of rotation to move from the fully open position to the closed position.
When the disc is perpendicular to the pipe centerline, the valve is in the closed position. When the disc is parallel to the centerline of the pipe, the valve will be fully open (allowing maximum fluid flow). The size of the flow control mechanism (disc) is approximately equal to the inside diameter of the adjacent pipeline.
These valves are available in different sizes and designs that determine their performance in industrial process applications; sanitary valve applications; fire protection services; heating, ventilation, and air conditioning (HVAC) systems; and slurries. In a broad sense, butterfly valves are critical for flow regulation and flow isolation.
Wafer Centerline Butterfly Valve
Butterfly valves are typically installed between flanges. Butterfly valves should be installed at least four to six times the diameter of the pipe from discharge nozzles, elbows or branches to minimize the effects of turbulence.
Prior to installation, clean the piping and check the flanges for smoothness/levelness. Make sure the piping is aligned. Install the valve with the valve flap in the partially open position. It may be necessary to unfold the flange to avoid damage to the valve seat surface. Use positioning holes or slings around the valve body when lifting or moving the valve. Avoid lifting the valve at the actuator or its operator.
Align the valve with the insertion bolts in the adjacent piping. Tighten the bolts by hand, then use a torque wrench to slowly and evenly tighten the bolts to estimate the clearance between them and the flange. Turn the valve to the fully open position and use a torque wrench to tighten the bolts to check that they are evenly tensioned.
Electric Wafer Butterfly Valve
Valve maintenance includes lubrication of mechanical parts, inspection and repair of actuators. Valves that require periodic lubrication contain greased fittings. A sufficient amount of lithium-based grease should be applied at recommended intervals to minimize rusting and corrosion.
It is also important to inspect the actuator periodically to identify any signs of wear or loose electrical, pneumatic or hydraulic connections that may affect valve operation.
In addition, the user should clean all parts of the butterfly valve with a silicone-based lubricant. The valve seat should be inspected for any signs of wear and replaced if necessary. Butterfly valve discs used in dry applications (such as compressed air service) require lubrication. Butterfly valves that are not cycled frequently should be operated at least once a month.
Flange Triple Eccentric Hard Seal Butterfly Valve
Valve selection may seem like a choose and plug activity, but there are several technical specifications to consider. The first involves understanding the type of fluid control required and the type of fluid to be served. Corrosive fluid service requires valves made of stainless steel, nichrome, or other corrosion-resistant materials.
Users need to consider the capacity of the piping system, pressure and temperature variations, and the level of automation required. While actuated butterfly valves provide precise flow control, they are more expensive than their manually operated counterparts. Butterfly valves are not controllable and do not provide a complete port.
Handle Flange Type Butterfly Valve
If the user is unsure of the chemical compatibility of the process or drive selection, a qualified valve company can assist in ensuring the correct selection.
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