Butterfly valves
Butterfly valves correctly specified and supplied
Butterfly valves examined up close
Butterfly valves are quarter turn valves in which a disc rotates within the line to open or close the flow path. The subject of butterfly valves touches both the construction of the valve and the way the plant is operated. There are assumptions circulating about butterfly valves that do not hold up under closer examination. Quarter turn operation allows fast switching and is easy to automate with a pneumatic or electric actuator. In a partly open position a butterfly valve can throttle, although a genuine control duty is better placed with a control valve. A butterfly valve is a quarter turn valve in which a circular disc rotates in the line to open or close the flow path. For butterfly valves this means that construction and operating conditions cannot be judged separately. That principle explains why butterfly valves behaves differently from a standard execution under heavier duty. We regularly see that a small change in the execution of butterfly valves makes a large difference to maintenance frequency. A concentric butterfly valve has the disc axis in the centre of the bore and seals on an elastomer or PTFE liner. An offset butterfly valve moves the axis, so the disc clears the seat immediately on opening and no rubbing wear occurs. It pays to understand the working principle behind butterfly valves first, because the limits follow from that principle.
Butterfly valves and the decisive technical choices
The disc remains in the flow at all times, which keeps the valve compact but adds a small permanent resistance. With butterfly valves the seat is the component that determines performance, and the body is rarely the limiting factor. The balance between required tightness and available operating force is a recurring tension on butterfly valves. The market splits between concentric valves with a soft liner and offset valves with a metal seat. Metal seated executions suit temperatures, pressures and media where a liner no longer functions. At larger diameters the difference in weight and price against a ball or gate valve is considerable. The main strength of the butterfly valve is its compact construction, because it takes up almost no space in the direction of the pipe. At larger diameters the saving in weight and installed length against a ball or gate valve becomes substantial. On standard executions the liner is the weak point, and that is exactly why metal seated designs exist. We supply butterfly valves as a loose product and as an assembled unit with actuator and accessories. With butterfly valves it pays to include phase changes in the medium, because those sharply increase the load on the seal. What weighs heaviest on butterfly valves in practice is the combination of temperature and differential pressure, not either one alone.
Typical applications for butterfly valves
They are used across industry, from water treatment and utilities to chemicals, food production and power generation. Butterfly valves appear in almost every industry, from water treatment to chemicals and from food to power generation. In hydrogen, technical gases and steam those are the executions that make the difference between working and leaking. During turnarounds butterfly valves is regularly on the critical path, and then predictability matters more than the lowest price. On project supply we record per position which execution of butterfly valves was delivered, including materials and tests. For butterfly valves the sector determines which documentation and tests belong with the delivery. Demand for butterfly valves reaches us mainly from projects where the standard range falls short. Dutch Valve Vision focuses on the heavier segment, with metal seated and offset executions for demanding media. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion. On replacement we always check the existing installation dimensions for butterfly valves, so the pipework can stay untouched. Our customers use butterfly valves in positions where a failure has immediate consequences for production.
Choosing the right butterfly valves
Standardising across several positions makes butterfly valves simpler in maintenance and in spare parts management. When replacing an existing valve we check face to face length, flange standard and actuator mounting. Installation orientation and free space for the disc are points that are often overlooked in practice. We also look at operating torque, because it rises quickly at larger sizes and higher differential pressures. We never recommend a heavier execution of butterfly valves than needed, because over specification only raises price and lead time. The cleaning and flushing procedure counts too on butterfly valves, because it can be more aggressive than the process itself. Where there is doubt about butterfly valves we quote two executions side by side, with the trade offs stated explicitly. A butterfly valve stops being a simple product as soon as medium, pressure or temperature moves away from average. Where there is doubt about the right type we prepare a comparison based on your process data. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. On butterfly valves we also state what an execution cannot do, because that prevents more problems than a list of advantages. For butterfly valves total cost of ownership weighs more than purchase price, certainly when replacement has to happen during a shutdown.
Dutch Valve Vision as your supplier of butterfly valves
Even when the specification for butterfly valves is not yet finalised, you can bring the question to us. 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. We supply butterfly valves as a loose product or as a fully assembled unit with actuator and accessories. We think along on the spare parts strategy for butterfly valves, so critical positions stay covered. Dutch Valve Vision stays available after delivery of butterfly valves for technical questions and for parts. Documentation such as material certificates, test reports and declarations is supplied as standard, matched to what the project requires. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. Documentation on butterfly valves has to be the kind a buyer or inspector accepts without discussion. We work on butterfly valves under a KIWA ISO 9001 certified quality system, which safeguards traceability. We record which execution of butterfly valves was delivered, so a follow up delivery or spare part matches exactly later on. On butterfly valves we come back with a proposal that explains why we recommend a particular execution. For repeat orders of butterfly valves we record the configuration, so a follow up delivery is identical to the first. Bring us your question at sales@dutchvalvevision.com or +31 (0)70-2210560, even when the specification is not finalised yet.
Frequently asked questions about butterfly valves
What exactly does butterfly valves mean?
A concentric butterfly valve has the disc axis in the centre of the bore and seals on an elastomer or PTFE liner. Metal seated executions suit temperatures, pressures and media where a liner no longer functions. Butterfly valves are quarter turn valves in which a disc rotates within the line to open or close the flow path. In a partly open position a butterfly valve can throttle, although a genuine control duty is better placed with a control valve. For butterfly valves a good specification up front is cheaper than a correction afterwards. The answer on butterfly valves depends strongly on operating conditions, which is why we always ask for those first. We find that questions about butterfly valves almost always come back to the same three points: medium, temperature and required tightness. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users.
Which executions of butterfly valves are available?
An offset butterfly valve moves the axis, so the disc clears the seat immediately on opening and no rubbing wear occurs. On standard executions the liner is the weak point, and that is exactly why metal seated designs exist. A butterfly valve stops being a simple product as soon as medium, pressure or temperature moves away from average. Quarter turn operation allows fast switching and is easy to automate with a pneumatic or electric actuator. We see this come back regularly in enquiries about butterfly valves, and the answer is rarely a single sentence. This is one of the points on butterfly valves where suppliers differ most clearly from one another. How butterfly valves behaves under varying load says more about the quality of the selection than behaviour under steady load. 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.
Which materials are used for butterfly valves?
At larger diameters the difference in weight and price against a ball or gate valve is considerable. The disc remains in the flow at all times, which keeps the valve compact but adds a small permanent resistance. The main strength of the butterfly valve is its compact construction, because it takes up almost no space in the direction of the pipe. We supply butterfly valves as a loose product and as an assembled unit with actuator and accessories. In most projects butterfly valves turns out to be less standard than it first appears. The answer to this question on butterfly valves changes as soon as the medium or the temperature changes. In practice we find that most failures around butterfly valves come not from the material but from a wrong assumption during selection. Alongside QUADAX and PRUSS we represent Pibiviesse, Schroeder, Striko, Malbranque, Daume, FluoroSeal and Guichon, so we can select the right brand for each project.
What should I watch technically on butterfly valves?
What should I watch technically on butterfly valves?
Which applications call for butterfly valves?
They are used across industry, from water treatment and utilities to chemicals, food production and power generation. Dutch Valve Vision focuses on the heavier segment, with metal seated and offset executions for demanding media. Butterfly valves appear in almost every industry, from water treatment to chemicals and from food to power generation. In hydrogen, technical gases and steam those are the executions that make the difference between working and leaking. Our experience with butterfly valves comes from projects in chemicals, power generation, technical gases and offshore. If you are unsure about this on butterfly valves, we are glad to put the question alongside the actual process data. We supply butterfly valves both for new build and for replacement within existing installations. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion.
What determines the price and lead time of butterfly valves?
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 come back with a proposal that explains why we recommend a particular execution, including the alternatives we considered. For an accurate quotation we need the nominal diameter, the pressure class, the medium, the operating temperature and the required actuation. 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. On butterfly valves we include start up and shutdown, because that is where the heaviest loading occurs. On butterfly valves we prefer a well founded answer to a fast one that turns out to be wrong later. Even when the specification for butterfly valves is not yet finalised, you can bring the question to us. Bring us your question at sales@dutchvalvevision.com or +31 (0)70-2210560, even when the specification is not finalised yet.
What about maintenance and spare parts on butterfly valves?
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. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. Where there is doubt about the right type we prepare a comparison based on your process data. Documentation such as material certificates, test reports and declarations is supplied as standard, matched to what the project requires. We always explain why we arrive at a particular recommendation on butterfly valves, so you can follow the reasoning yourself. For butterfly valves a good specification up front is cheaper than a correction afterwards. A tag plate with project data belongs with butterfly valves as standard where the project requires it. Dutch Valve Vision supplies special valves for special applications from its base in Monster, the Netherlands, with QUADAX and PRUSS as the core brands in the programme.
How do I request a quotation for butterfly valves?
On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. A P&ID, a datasheet or even a photograph of the existing installation often helps us faster than a long description. Our experience with butterfly valves comes from projects in chemicals, power generation, technical gases and offshore. On butterfly valves we include start up and shutdown, because that is where the heaviest loading occurs. Our specialists are happy to discuss butterfly valves on the basis of your P&ID, your datasheet or simply a photograph of the situation. Send us your DN, pressure class, medium and temperature at sales@dutchvalvevision.com, or call +31 (0)70-2210560 to speak to a specialist.