Butterfly Valves - API 609, BS 5155, ASME B 16.34, ISO 5752

Flowtorq Engineering is best manufacturer of butterfly valves. Butterfly valves are mainly used to shutt off, distribute and change the direction of fluid medium flow in pipeline. Sometimes butterfly valves are used for flow regulation and control. Similar to Ball valves, butterfly valves are generally quarter turn operated valves, i.e. needs to be operated with a rotation of 90 degrees and a small turning torque to close tightly. These valves are operated by lever, Gear operated handwheel or pneumatic / electric actuators. The body is usually very short in running lenght as compared to other types of valves and is usually through in cross sectional area. This body cavity provides a direct flow path with little resistance for flow and very little pressure drop. Butterfly Valves are designed as per BS 5155, API 609, ASME B 16.34 and ISO 5752 standards.

Function

Butterfly valves are widely used for ON-OFF duty and sometimes for flow regulation as well. Due to its compact design, these valves provide little or no flow resistance and is helpful in minimising pressure drops and losses. The size of the flow path generally constant in a linear manner throughout body and disc. This means that the flow rate does not change at any given point, provided the valve is full open. This results into low pressure drop and flow reduction. Butterfly valves have a variety of configurations and type typically centerline / centric design, double eccentric (doube offset) and triple eccentric (triple offset) types. In addition, several customisations can be done as per process requirements, applications, etc.

Operation

Similar to ball valves, Butterly valves (BS 5155, API 609, ASME B 16.34 and ISO 5752) are operated by a rotating a lever or gearbox connected handwheel coupled with stem that is fixed to the disc inside body of valve. They are characterised as quarter turn valves. The stem is rotated 90 degree and the valve is thus operated, providing a visual indication of valve position as well. Sometimes actuators is attached to the stem on top so that it rotates the stem to operate the valve. The actuator are often are coupled into the stem from top. They may have a pointer over the actuator indicate valve position. Butterfly valves may have flanged ends drilled according to pipeline-compatible flange dimensional standards, wafer type without flanges or lugged type to suit appropriate flanges. Butterfly valves are typically constructed from dusctile iron, cast iron, cast carbon steel, stainless steel, alloy steels, etc. For flow regulation, actuators are usually used with positioners to control flow accurately. Flow control is usually calculated and termed as 'Valve CV' also known as 'Co-efficient of Flow Value".

triple offset

Construction of API 609 Butterfly Valves

Centerline Type

Butterfly Valves of centerline type or concentric types are having stem axis perpendicular to body axis with no offset distance. This is the most commonly used type as API 609.

Double Eccentric (Double Offset)

Unlike concentric or centerline butterfly valve, The stem and disc are having offset distance on 2 axes. This ensures higher performance than centerline type.

Triple Eccentric (Triple Offset)

Formore high pressure, temperature and critical applications, triple offset type butterfly valves are used. The disc, Stem are having offset in 2 axes and the third axis offset comes in the form of cone originating parallel to body plane. This ensures tight sealing on the seat surfaces.

Seats

As per the application, butterfly valves seats are carefully selected either in completely soft seat, completely metal seat and fire safe seats which are soft seating surface as primary and metal sealing surface as a secondary. These seats are selected based on applications by process engineers and engineering consultants. In centerline type, Soft Seats are fully lined and moulded inside butterfly valves body. Whereas in double offset and triple offset types, seats are usually fixed with retainer rings fastened to body.

Applications

Industrial applications such as oil and gas, petrochemicals, chemical, power generation, mining and industries use this valves. What makes this useful is that its simple operation and its ability of flow control in addition to on-off duty. There is also a pre calculated pressure drop and flow CV calculation which is as per the flow requirements of process.

Why Select and Use Flowtorq API 609 Butterfly Valves ?

Easy Availibility
Less Weight and compact construction
Wide range of application range with respect to temperature and pressure
Zero leakage ability
Fire Safe design availability
Economic Cost
Wide Range of Size from 1/2" (half inch) to large sizes till 40" inches or above
Easy Operation
Easy Maintenance and handling
Light but strong Construction
Wide Variety of internal trim parts variants
Long Service Life
Can be used for flow control and ON-OFF as well.

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Butterfly Valves General Specification

Size Range – 1/2″ to 40″ and above
Centerline Type, Double Eccentric (Double Offset), Triple Eccentric (Triple Offset) Types
Pressure Rating – 150#, 300#, 600#, PN 10, PN 16, PN 20, etc.
Certifications – CE, ISO, etc.
Inspected & Witnessed By third party agencies
API Valves, ATex Valves, CE Valves, Process Valves, Gas Valves, Water Valves, Cryogenic Service, Fire Safe