Anti surge valve
Everything about anti surge valve for industry
The technology behind anti surge valve
An anti surge valve protects a compressor against surge by recirculating or venting gas the moment the operating point moves towards the surge line. There are assumptions circulating about anti surge valve that do not hold up under closer examination. We find that questions about anti surge valve almost always come back to the same three points: medium, temperature and required tightness. On gas and vapour service high pressure ratios produce noise and vibration, and a multistage trim is then used to divide the pressure drop. The Kv value states how many cubic metres of water per hour pass through the valve at one bar differential pressure, and that figure is the basis of every calculation. The difference with an isolation valve is that a control valve has to work accurately and stably in every intermediate position, while an isolation valve only has to be open or closed. The balance between required tightness and available operating force is a recurring tension on anti surge valve. In practice we find that most failures around anti surge valve come not from the material but from a wrong assumption during selection. With anti surge valve the seat is the component that determines performance, and the body is rarely the limiting factor. An equal percentage characteristic is used most often, because it largely compensates for the non linearity of the rest of the system. A control valve modulates the opening in the line so that a process variable such as pressure, flow, level or temperature stays at its setpoint. It pays to understand the working principle behind anti surge valve first, because the limits follow from that principle.
Anti surge valve and the decisive technical choices
Surge is a violent flow reversal inside the compressor, and it can wreck the machine in a handful of cycles. How anti surge valve behaves under varying load says more about the quality of the selection than behaviour under steady load. We regularly see that a small change in the execution of anti surge valve makes a large difference to maintenance frequency. Stroking speed is the defining requirement, because the valve has to open in a fraction of a second and then control smoothly. Cavitation occurs when local pressure drops below vapour pressure and the vapour bubbles then implode, which eats through trim in a short time. The valve characteristic, whether linear, equal percentage or quick opening, defines how flow area relates to travel and therefore how the loop behaves. Rangeability states between which extremes the valve still controls reliably, and outside that band control becomes unstable. The valve therefore has to be both fast and accurate, which is an unusual and demanding combination in one product. On commissioning we record the settings and calibration, so a later fault can be traced. PRUSS builds control valves for the heavier end of this spectrum, with steam, high temperature and safety functions as its core territory. For anti surge valve this means that construction and operating conditions cannot be judged separately. Operating conditions govern the service life of anti surge valve far more strongly than the nominal figures on a datasheet.
Applications of anti surge valve in industry
Anti surge valves are used on process compressors in refineries, gas processing, air separation and chemical plants. In steam plant and boiler houses control valves handle the pressure and temperature control that keeps the installation within its design limits. In power generation they sit around turbines, boilers and bypass circuits, where speed and reliability are decisive. In plants where anti surge valve is applied, the emphasis is on reliability rather than lowest purchase price. The application range of anti surge valve runs from simple utility duty to heavy process plant, with a corresponding difference in execution. On replacement we always check the existing installation dimensions for anti surge valve, so the pipework can stay untouched. Demand for anti surge valve reaches us mainly from projects where the standard range falls short. In chemicals and petrochemicals they control flows and levels in processes where medium properties weigh heavily. 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. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users. On project supply we record per position which execution of anti surge valve was delivered, including materials and tests. We see demand for anti surge valve rising in hydrogen and ammonia projects, where tightness requirements are high.
Choosing the right anti surge valve
We never recommend a heavier execution of anti surge valve than needed, because over specification only raises price and lead time. Oversizing is the most common mistake, because an oversized valve only controls in the first few degrees of travel and wears there rapidly. Correct sizing starts from the full operating envelope, so minimum, normal and maximum flow with their corresponding pressures. Actuator and positioner belong to the selection, because a well chosen valve with the wrong actuator still controls poorly. If a simpler type will do the job, we say so on anti surge valve, even when that means a smaller order. The right choice around anti surge valve starts with a full set of process data rather than with a request for a price. On anti surge valve we also state what an execution cannot do, because that prevents more problems than a list of advantages. A control valve that audibly whistles or vibrates is telling you something about the selection, and that signal should be solved rather than insulated away. During overhaul we measure trim and seat and advise whether reworking is sufficient or replacement works out cheaper. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. The required leakage class often drives the choice around anti surge valve more strongly than the budget does. The cleaning and flushing procedure counts too on anti surge valve, because it can be more aggressive than the process itself.
Anti surge valve supplied with technical advice
Dutch Valve Vision stays available after delivery of anti surge valve for technical questions and for parts. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users. We supply anti surge valve as a loose product or as a fully assembled unit with actuator and accessories. For anti surge valve you can come to Dutch Valve Vision for the selection, the delivery and the support afterwards. On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. 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 work on anti surge valve under a KIWA ISO 9001 certified quality system, which safeguards traceability. Documentation on anti surge valve has to be the kind a buyer or inspector accepts without discussion. Tests around anti surge valve are carried out by us or on our instruction according to the requirements in the specification. For repeat orders of anti surge valve we record the configuration, so a follow up delivery is identical to the first. Even when the specification for anti surge valve is not yet finalised, you can bring the question to us. You can reach us on +31 (0)70-2210560 and at sales@dutchvalvevision.com, and our office hours are Monday to Friday from 09:00 to 17:00.
Frequently asked questions about anti surge valve
What exactly does anti surge valve mean?
An anti surge valve protects a compressor against surge by recirculating or venting gas the moment the operating point moves towards the surge line. The Kv value states how many cubic metres of water per hour pass through the valve at one bar differential pressure, and that figure is the basis of every calculation. The difference with an isolation valve is that a control valve has to work accurately and stably in every intermediate position, while an isolation valve only has to be open or closed. The valve characteristic, whether linear, equal percentage or quick opening, defines how flow area relates to travel and therefore how the loop behaves. The answer to this question on anti surge valve changes as soon as the medium or the temperature changes. On anti surge valve we prefer a well founded answer to a fast one that turns out to be wrong later. The term anti surge valve is used broadly in the market, which is why it helps to define precisely what it means in your case. Alongside QUADAX and PRUSS we represent Pibiviesse, Schroeder, Striko, Malbranque, Daume, FluoroSeal and Guichon, so we can select the right brand for each project.
Which executions of anti surge valve are available?
An equal percentage characteristic is used most often, because it largely compensates for the non linearity of the rest of the system. On gas and vapour service high pressure ratios produce noise and vibration, and a multistage trim is then used to divide the pressure drop. Cavitation occurs when local pressure drops below vapour pressure and the vapour bubbles then implode, which eats through trim in a short time. Surge is a violent flow reversal inside the compressor, and it can wreck the machine in a handful of cycles. The answer on anti surge valve depends strongly on operating conditions, which is why we always ask for those first. That makes anti surge valve a subject where discussion up front pays for itself in operation. That principle explains why anti surge valve behaves differently from a standard execution under heavier duty. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects.
Which materials are used for anti surge valve?
Rangeability states between which extremes the valve still controls reliably, and outside that band control becomes unstable. The valve therefore has to be both fast and accurate, which is an unusual and demanding combination in one product. A control valve modulates the opening in the line so that a process variable such as pressure, flow, level or temperature stays at its setpoint. A control valve that audibly whistles or vibrates is telling you something about the selection, and that signal should be solved rather than insulated away. For anti surge valve a good specification up front is cheaper than a correction afterwards. We always explain why we arrive at a particular recommendation on anti surge valve, so you can follow the reasoning yourself. What weighs heaviest on anti surge valve in practice is the combination of temperature and differential pressure, not either one alone. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion.
What should I watch technically on anti surge valve?
What should I watch technically on anti surge valve?
Which applications call for anti surge valve?
In chemicals and petrochemicals they control flows and levels in processes where medium properties weigh heavily. In power generation they sit around turbines, boilers and bypass circuits, where speed and reliability are decisive. Anti surge valves are used on process compressors in refineries, gas processing, air separation and chemical plants. In steam plant and boiler houses control valves handle the pressure and temperature control that keeps the installation within its design limits. If you are unsure about this on anti surge valve, we are glad to put the question alongside the actual process data. In most projects anti surge valve turns out to be less standard than it first appears. During turnarounds anti surge valve is regularly on the critical path, and then predictability matters more than the lowest price. 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.
What determines the price and lead time of anti surge valve?
We come back with a proposal that explains why we recommend a particular execution, including the alternatives we considered. A P&ID, a datasheet or even a photograph of the existing installation often helps us faster than a long description. 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. We see this come back regularly in enquiries about anti surge valve, and the answer is rarely a single sentence. On anti surge valve we include start up and shutdown, because that is where the heaviest loading occurs. Our specialists are happy to discuss anti surge valve on the basis of your P&ID, your datasheet or simply a photograph of the situation. Requests can be submitted by phone on +31 (0)70-2210560, by e-mail at sales@dutchvalvevision.com or through the contact form on our website.
What about maintenance and spare parts on anti surge valve?
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. 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. On commissioning we record the settings and calibration, so a later fault can be traced. That makes anti surge valve a subject where discussion up front pays for itself in operation. We see this come back regularly in enquiries about anti surge valve, and the answer is rarely a single sentence. We record which execution of anti surge valve was delivered, so a follow up delivery or spare part matches exactly later on. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users.
How do I request a quotation for anti surge valve?
For an accurate quotation we need the nominal diameter, the pressure class, the medium, the operating temperature and the required actuation. If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. 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. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. If you are unsure about this on anti surge valve, we are glad to put the question alongside the actual process data. We always explain why we arrive at a particular recommendation on anti surge valve, so you can follow the reasoning yourself. On anti surge valve we come back with a proposal that explains why we recommend a particular execution. Bring us your question at sales@dutchvalvevision.com or +31 (0)70-2210560, even when the specification is not finalised yet.