- Gate valve
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- DN1000 Extension stem double flange soft seal gate valveDIN F4 resilient seated gate valveDN450-1200 Resilient Seated Gate ValveDIN F5 resilient seated gate valveSocket connection soft seal gate valveUnderground cap soft seal gate valveBS5163 rising stem soft seal gate valveHard seal gate valveAPI slab Gate ValveStainless steel flange gate valveWafer knife gate valvePneumatic gate valveSoft seal gate valveExtension stem gate valveUL/FM fire protection groove ends gate valveRising stem forged steel gate valvecarbon steel gate valveStainless steel threaded gate valveDIN soft seal gate valveANSI soft sealing gate valve 200PSICast iron gate valveBS resilient seated gate valve
- Butterfly valve
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- DN900 pneumatic triple eccentric hard seal butterfly valveD643H Triple Eccentric Butterfly ValveD343H Hard seal butterfly valveMulti standard EPDM seated butterfly valveSingle flange butterfly valveDN2000 Double eccentric butterfly valveFlange butterfly valveLug butterfly valveWafer butterfly valve with handleWorm gear operated butterfly valveWafer lined fluorine butterfly valveStainless steel wafer butterfly valveStainless steel flanged butterfly valveThree eccentric flange butterfly valvePneumatic flanged butterfly valvePneumatic wafer butterfly valveTriple eccentric butterfly valve wafer typeWafer butterfly valve ULC approvedInflatable seat butterfly valveHigh performance butterfly valveGrooved end butterfly valveElectric soft seal butterfly valveFlange fluorine lined butterfly valveHandle aluminum butterfly valveWorm Gear Aluminum Butterfly ValveFull PTFE lined butterfly valve wafer typeOne stem no-pin wafer butterfly valveMulti standard aluminum stem butterfly valveStainless Steel wafer Butterfly ValveAluminium handle operated lug butterfly valveLever Operated Flange Butterfly ValveButterfly valve stemButterfly valve discButterfly valve seat
- Ball valve
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- DN1400 top-mounted eccentric semi-ball valveFlanged three-way ball valveFully welded ball valveNatural gas ball valveHigh platform flange ball valve1 PC ball valveFixed ball valvePTFE seat flanged ball valveMetal seat ball valveAPI 6D ball valve3 Piece ball valveFull Bore 3 way ball valve L-Port3 Way T-Port ball valve2PC Ball valve female thread stainless steel
- Globe Valve
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- API Carbon Steel Globe ValveBellows Globe ValveStainless steel flange globe valveStainless steel thread S type globe valveStainless steel thread B type globe valveCast Steel Globe ValvePiston Globe ValveWCB Carbon Steel Globe Check Valveelectric motorized control stainless steel SS316 globe valveBrass Globe ValveCryogenic Globe valveHT200 Globe ValveThreaded Stainless Steel Globe ValveGG25 Globe ValveANSI API Cast Steel And Stainless Steel Globe valve
- Check valve
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- Rubber seal check valveDN800 Slow closing check valveDN800 Rubber Disc Check ValveButterfly Buffering Check Valvecheck valve with counter weightSilent Check ValveWCB Swing check valveSwing Check ValveSingle Chip Check Valve H74WStainless Steel Wafer Check ValveSwing Start Check ValveFoot check valveAPI Swing Check ValveDIN Flange check valveSingle plate check valveLifting Check ValveBottom ValveHammer Diminish Noises Check ValveWafer Check ValveWafer dual plate check valve
- Water Meter
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- Vertical Type Water MetersStainless steel threaded water meterPiston water meterPlastic water meterMore flow rotor dry water meterspiral vane flange water meterCI wotlman water meter with pulse outputLXCLG(R) Vertical removable element woltman cold (hot) water meterSingle flow rotor dry water meterPrepaid Token Water MeterElectromagnetic flowmeterRotary Piston Liquid Sealed Water MeterRotary Piston Liquid Sealed Water Meter
- Air valve
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- Double ball exhaust valveDoubleair Air Valve SaudiDoubleair Air Valve Southeast AsiaDoubleair Air Valve South AmericaDouble Air ValveThreaded Air ValveSingle Air ValveTriple Functions Air ValveAutomatic Air Release ValveAutomatic release valveAutomatic exhaust valveComposite Exhaust Air ValveBrass exhaust valveDouble Ball Air Valve
- Pipe Repair & Coupling
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- Flexible Multi-Function Pipe Coupling ZFJ-SSS Semi-Circle Pipe Repair Clamp SJW-HDuctile Iron Band Repair ClampStainless Steel Band Repair ClampDouble-Section Pipe Repair CouplingFolding Type Pipe RepairSingle-Section Multi-Function Pipe Coupling MF-SGear-Ring Type Multi-Function Pipe Coupling GR-SZBW Damping Corrugated Hose
- Dismantling Joint
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- VSSJAFC(CC2F) Detachable Flange Transmission JointVSSJA-2(B2F) Double Flange Limited Expansion JointVSSJA-1(BF) Single Flange Limited Expansion JointVSSJA(AF) Flange Loose Expansion JointJGD-B Threaded Rubber JointZBW Damping Corrugated HoseKXT-S Flexible Dual-Spherical Rubber JointKXT Rubber Soft JointFlange Adaptor
How It Works: Butterfly Valves
2017-11-30
A butterfly valve is a flow regulating disc valve. According to the BVAA, a butterfly valve is “a valve in which the obturator rotates about an axis at right angles to the direction of flow and, in the open position flow passes around the obturator.”
In other words, a butterfly valve consists of a circular disc or plate built with a stem through the middle or attached offset. When opened, the disc pivots 90 degrees in the valve bore, aligning with the flow, creating a nearly unrestricted flow path. Butterfly valves operate similar to ball valves in their 90 degree rotation and allow for quick shutoff.
Butterfly valves have gained popularity over the years due to their thin profile between flanges, making them lighter in weight and creating a smaller install footprint. This compact design also usually makes the initial cost for these valves lower when compared to other valve designs.
There are different types of butterfly valves and each type has unique design features and applications. Each type is defined by the orientation of the stem to the disc and the seating angle that the disc closes on.
The most basic butterfly valve design is commonly called a concentric or resilient-seated butterfly valve. In this type of valve, the stem is centered in the middle of the valve disc, which is centered in the pipe bore. This valve typically has a rubber (or resilient) seat and relies on the disc having a high level of contact with the seat to effect a seal. The disc will contact the seat the earliest (85+/- degrees) during the 90 degree rotation.
In a single-offset butterfly valve, the stem is located behind the disc. There are few, if any, valves of this type left on the market today due to the development of the double-offset, or high-performance, valve. The single-offset of the stem causes the disc to contact the seat with three to four degrees left to travel with the idea that less seat contact will enable the valve to last longer.
The double-offset or high-performance butterfly valve has a disc with two offsets and can be rated up to 1480 psi. Similar to a single-offset design, the stem is located behind the disc. With the high-performance butterfly valve, the second offset’s stem is moved once more off the center of the disc to one side. This geometry of offsets enables the 90 degree disc rotation to “rub” over the seat for only one to three degrees of the 90 degree rotation.
The double-offset butterfly valve is used in systems requiring higher pressure resistance. The disc is positioned in the center of the pipe bore and arranged to increase sealing ability and decrease wear to the valve. WKM high-performance butterfly valve is ideal for handling water, oil, steam, and gas in a cost effective, light weight design. The WKM butterfly valve’s corrosion-resistant, single-component thrust bearing/disc spacer reduces body wear and helps ensure positive centering of disc in the valve bore.
Both resilient and high-performance butterfly valves can be operated by handles, gears, or actuators. These devices move the valve disc to the optimal position for complete shutoff or fully open the valve. Resilient and high-performance butterfly valves are used mainly in the water, chemical and petrochemical industries, but can also be used in fuel handling systems, power, and many other applications.
The last type of butterfly valve is the triple-offset butterfly valve (a.k.a. TOV or TOBV). This type of butterfly valve is applied in difficult services where reliable performance under harsh conditions is needed. Exactly like a double-offset valve, the stem is located behind the disc and offset to one side (double-offset). The third offset is the geometry of the seating surface. This seating surface creates a sort of cone-shape of the disc and seat, which wedges into the seat with very minimal contact between the sealing surfaces until fully closed. By reducing the amount of contact that the seat has with the disc, sealing becomes more efficient and the life of the valve is extended.
TOVs are typically metal–seated, unlike single and double-offset butterfly valves. The Cameron WKM TOV has a metal seat design, which allows it to achieve zero leakage* in either direction for extreme services. The true triple-offset geometry of the WKM TOV allows for bubble-tight* sealing to create a fully bi-directional zero-leakage* shut-off valve.
Triple offset butterfly valves are commonly used in steam, chemical, refining, and offshore oil and gas applications up to 1400° F (760° C). The rugged metal seats can also withstand a high degree of abrasion and shock and, with appropriate material selection, can also be utilized in cryogenic services such as LNG and NPG facilities.