Torque seated butterfly valve

Torque seated butterfly valve correctly specified and supplied

Torque seated butterfly valve: the working principle in practice

A torque seated butterfly valve achieves its seal by applying torque at the end of the closing stroke, rather than by compressing a soft seat. In practice torque seated butterfly valve is rarely a standard question once medium and temperature move away from average. We find that questions about torque seated butterfly valve almost always come back to the same three points: medium, temperature and required tightness. That offset removes the rubbing movement across the seat, which is the main cause of wear in concentric butterfly valves. In an offset butterfly valve the centre of the disc does not sit in the centre of the flow, so the disc lifts away from the seat immediately on opening. Since a controlled contact face is formed in the closed position, no run in period is required and the valve performs to specification from the first stroke. With torque seated butterfly valve it pays to include phase changes in the medium, because those sharply increase the load on the seal. Operating conditions govern the service life of torque seated butterfly valve far more strongly than the nominal figures on a datasheet. How torque seated butterfly valve behaves under varying load says more about the quality of the selection than behaviour under steady load. A triple offset design combines two geometric offsets with an inclined cone axis, so contact between disc and seat only occurs in the last few degrees of travel. The result of that fourth offset is that sealing performs equally well in both flow directions, which is not a given with triple offset valves. The subject of torque seated butterfly valve touches both the construction of the valve and the way the plant is operated.

Torque seated butterfly valve and the decisive technical choices

Because the seal comes from a defined torque, the tightness of the valve is repeatable and does not depend on material memory. That principle explains why torque seated butterfly valve behaves differently from a standard execution under heavier duty. On torque seated butterfly valve we always check the full operating envelope, including start up and shutdown. Torque seating requires an actuator sized on the seating torque, not just on the running torque of the valve. Both the seat and the sealing edge are metal, so temperature, steam, vapour and aggressive media cause no degradation of the seal. A quadruple offset construction adds a fourth offset, which distributes the load far more evenly around the full circumference of the seat. Because sealing is achieved by torque rather than by deformation of an elastomer, tightness is maintained over thousands of cycles. The absence of elastomer compression means the sealing performance does not drift as the valve ages. Installation orientation is less critical on bidirectional designs, which prevents mistakes during field assembly. In vacuum service a metal seated offset valve outperforms an elastomer seat, because there is no liner that can be drawn inwards. A correct execution of torque seated butterfly valve accounts for real operating conditions and not only for design values. For torque seated butterfly valve this means that construction and operating conditions cannot be judged separately.

Typical applications for torque seated butterfly valve

Torque seated designs are used on steam, high pressure gas, technical gases and other duties where repeatable tightness matters. In technical gases and hydrogen applications the metal seal is decisive, because small molecule size and emission limits reinforce each other. In chemical and petrochemical plants these valves are used where both tightness and emission requirements carry serious weight. On project supply we record per position which execution of torque seated butterfly valve was delivered, including materials and tests. Our customers use torque seated butterfly valve in positions where a failure has immediate consequences for production. Demand for torque seated butterfly valve reaches us mainly from projects where the standard range falls short. The application range of torque seated butterfly valve runs from simple utility duty to heavy process plant, with a corresponding difference in execution. Offshore, weight saving counts, and at larger diameters a butterfly valve saves considerably compared with a ball valve. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects. We work as a technical supplier rather than a catalogue reseller, which means we carry out the selection ourselves on the basis of medium, pressure, temperature and code requirements. In an existing plant torque seated butterfly valve is often part of a wider question about availability and maintenance. On replacement we always check the existing installation dimensions for torque seated butterfly valve, so the pipework can stay untouched.

How to select torque seated butterfly valve without mistakes

If a simpler type will do the job, we say so on torque seated butterfly valve, even when that means a smaller order. In selection we look first at medium and temperature, then at differential pressure, and only after that at body style and actuation. Operating torque is higher than on a concentric design, and that has to be reflected in the choice of actuator. When replacing an existing gate valve we check face to face length and flange connection, so the pipework does not have to be modified. Where there is doubt about torque seated butterfly valve we quote two executions side by side, with the trade offs stated explicitly. Standardising across several positions makes torque seated butterfly valve simpler in maintenance and in spare parts management. For torque seated butterfly valve total cost of ownership weighs more than purchase price, certainly when replacement has to happen during a shutdown. We never recommend a heavier execution of torque seated butterfly valve than needed, because over specification only raises price and lead time. Maintenance is limited to packing and bearings, and because the seat is metal there is no liner to replace. The disc can be reworked when worn, so the service life of the body is often many times that of the sealing components. If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. The right choice around torque seated butterfly valve starts with a full set of process data rather than with a request for a price. The cleaning and flushing procedure counts too on torque seated butterfly valve, because it can be more aggressive than the process itself.

Torque seated butterfly valve supplied with technical advice

Our specialists are happy to discuss torque seated butterfly valve on the basis of your P&ID, your datasheet or simply a photograph of the situation. Dutch Valve Vision operates under a KIWA ISO 9001 certified quality system, which in the RFQ stage of chemical and offshore projects is usually a hard requirement. Even when the specification for torque seated butterfly valve is not yet finalised, you can bring the question to us. We handle an enquiry for torque seated butterfly valve on its technical merits rather than as a price request that only produces a number. For torque seated butterfly valve you can come to Dutch Valve Vision for the selection, the delivery and the support afterwards. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. Material certificates and test reports are supplied with torque seated butterfly valve, matched to what the project requires. We work on torque seated butterfly valve under a KIWA ISO 9001 certified quality system, which safeguards traceability. Documentation on torque seated butterfly valve has to be the kind a buyer or inspector accepts without discussion. Dutch Valve Vision stays available after delivery of torque seated butterfly valve for technical questions and for parts. For repeat orders of torque seated butterfly valve we record the configuration, so a follow up delivery is identical to the first. Send us your DN, pressure class, medium and temperature at sales@dutchvalvevision.com, or call +31 (0)70-2210560 to speak to a specialist.

Frequently asked questions about torque seated butterfly valve

What exactly does torque seated butterfly valve mean?

Because sealing is achieved by torque rather than by deformation of an elastomer, tightness is maintained over thousands of cycles. The result of that fourth offset is that sealing performs equally well in both flow directions, which is not a given with triple offset valves. A quadruple offset construction adds a fourth offset, which distributes the load far more evenly around the full circumference of the seat. In an offset butterfly valve the centre of the disc does not sit in the centre of the flow, so the disc lifts away from the seat immediately on opening. We always explain why we arrive at a particular recommendation on torque seated butterfly valve, so you can follow the reasoning yourself. In most projects torque seated butterfly valve turns out to be less standard than it first appears. We approach torque seated butterfly valve from the question of what the plant has to do, not from the question of what happens to be in stock. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects.

Which executions of torque seated butterfly valve are available?

That offset removes the rubbing movement across the seat, which is the main cause of wear in concentric butterfly valves. Installation orientation is less critical on bidirectional designs, which prevents mistakes during field assembly. Maintenance is limited to packing and bearings, and because the seat is metal there is no liner to replace. Since a controlled contact face is formed in the closed position, no run in period is required and the valve performs to specification from the first stroke. That makes torque seated butterfly valve a subject where discussion up front pays for itself in operation. This is one of the points on torque seated butterfly valve where suppliers differ most clearly from one another. In practice we find that most failures around torque seated butterfly valve come not from the material but from a wrong assumption during selection. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion.

Which materials are used for torque seated butterfly valve?

In vacuum service a metal seated offset valve outperforms an elastomer seat, because there is no liner that can be drawn inwards. Torque seating requires an actuator sized on the seating torque, not just on the running torque of the valve. Both the seat and the sealing edge are metal, so temperature, steam, vapour and aggressive media cause no degradation of the seal. A triple offset design combines two geometric offsets with an inclined cone axis, so contact between disc and seat only occurs in the last few degrees of travel. If you are unsure about this on torque seated butterfly valve, we are glad to put the question alongside the actual process data. The answer on torque seated butterfly valve depends strongly on operating conditions, which is why we always ask for those first. We regularly see that a small change in the execution of torque seated butterfly valve makes a large difference to maintenance frequency. What defines us is that we would rather spend an extra half hour on the specification than ship the wrong valve that comes back two months later.

What should I watch technically on torque seated butterfly valve?

Which applications call for torque seated butterfly valve?

What determines the price and lead time of torque seated butterfly valve?

We quote a realistic lead time rather than an optimistic one, because a missed delivery date costs more than an extra week in the planning. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. A P&ID, a datasheet or even a photograph of the existing installation often helps us faster than a long description. On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. We see this come back regularly in enquiries about torque seated butterfly valve, and the answer is rarely a single sentence. The answer to this question on torque seated butterfly valve changes as soon as the medium or the temperature changes. We supply torque seated butterfly valve as a loose product or as a fully assembled unit with actuator and accessories. We are based at Vlotlaan 641, 2681 TZ Monster in the Netherlands and can be reached on +31 (0)70-2210560 and at sales@dutchvalvevision.com.

What about maintenance and spare parts on torque seated butterfly valve?

Documentation such as material certificates, test reports and declarations is supplied as standard, matched to what the project requires. For shutdowns and turnarounds we look at accelerated routes, and in those cases we are honest up front about what is and is not achievable. Lead times depend on the execution, because a standard size from a running series behaves very differently from a valve in an exotic alloy with NACE certification. We quote a realistic lead time rather than an optimistic one, because a missed delivery date costs more than an extra week in the planning. If you are unsure about this on torque seated butterfly valve, we are glad to put the question alongside the actual process data. In most projects torque seated butterfly valve turns out to be less standard than it first appears. On torque seated butterfly valve we make sure the chosen execution demonstrably meets the stated standards rather than merely looking plausible on paper. Dutch Valve Vision operates under a KIWA ISO 9001 certified quality system, which in the RFQ stage of chemical and offshore projects is usually a hard requirement.

How do I request a quotation for torque seated butterfly valve?

If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. We come back with a proposal that explains why we recommend a particular execution, including the alternatives we considered. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. For an accurate quotation we need the nominal diameter, the pressure class, the medium, the operating temperature and the required actuation. On torque seated butterfly valve we include start up and shutdown, because that is where the heaviest loading occurs. This is one of the points on torque seated butterfly valve where suppliers differ most clearly from one another. Our specialists are happy to discuss torque seated butterfly valve on the basis of your P&ID, your datasheet or simply a photograph of the situation. Call +31 (0)70-2210560 or send your specification to sales@dutchvalvevision.com and we will pick it up.