Pressure control valve

Everything about pressure control valve for industry

The working principle of pressure control valve

A pressure control valve holds pressure at its setpoint by adjusting the flow area, either upstream as a back pressure regulator or downstream as a reducing valve. Once pressure control valve is correctly specified it disappears from the fault list, and that is exactly the intention. We approach pressure control valve from the question of what the plant has to do, not from the question of what happens to be in stock. An equal percentage characteristic is used most often, because it largely compensates for the non linearity of the rest of the system. Cavitation occurs when local pressure drops below vapour pressure and the vapour bubbles then implode, which eats through trim in a short time. On gas and vapour service high pressure ratios produce noise and vibration, and a multistage trim is then used to divide the pressure drop. In practice we find that most failures around pressure control valve come not from the material but from a wrong assumption during selection. How pressure control valve behaves under varying load says more about the quality of the selection than behaviour under steady load. What weighs heaviest on pressure control valve in practice is the combination of temperature and differential pressure, not either one alone. 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. With pressure control valve the difference between a good and a mediocre solution often sits in details that do not show on a drawing.

What to watch technically on pressure control valve

Reducing and back pressure control are two different duties, and confusing them is a common specification error. We regularly see that a small change in the execution of pressure control valve makes a large difference to maintenance frequency. On pressure control valve we always check the full operating envelope, including start up and shutdown. Large pressure ratios generate noise and vibration, which is why multistage trim is used above a certain drop. Rangeability states between which extremes the valve still controls reliably, and outside that band control becomes unstable. 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. 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. On liquid duty the risk is cavitation, and on gas duty the limiting factor becomes sound level and vibration. 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. On commissioning we record the settings and calibration, so a later fault can be traced. With pressure control valve the seat is the component that determines performance, and the body is rarely the limiting factor. That principle explains why pressure control valve behaves differently from a standard execution under heavier duty.

Applications of pressure control valve in industry

They are used in steam distribution, gas supply, process lines and utility systems at multiple pressure levels. In steam plant and boiler houses control valves handle the pressure and temperature control that keeps the installation within its design limits. In chemicals and petrochemicals they control flows and levels in processes where medium properties weigh heavily. Demand for pressure control valve reaches us mainly from projects where the standard range falls short. In plants where pressure control valve is applied, the emphasis is on reliability rather than lowest purchase price. In an existing plant pressure control valve is often part of a wider question about availability and maintenance. On project supply we record per position which execution of pressure control valve was delivered, including materials and tests. In power generation they sit around turbines, boilers and bypass circuits, where speed and reliability are decisive. Alongside QUADAX and PRUSS we represent Pibiviesse, Schroeder, Striko, Malbranque, Daume, FluoroSeal and Guichon, so we can select the right brand for each project. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects. On replacement we always check the existing installation dimensions for pressure control valve, so the pipework can stay untouched. Our customers use pressure control valve in positions where a failure has immediate consequences for production.

Selection criteria for pressure control valve

For pressure control valve total cost of ownership weighs more than purchase price, certainly when replacement has to happen during a shutdown. On every selection we check for cavitation, flashing and sound level, because those three determine trim life. Correct sizing starts from the full operating envelope, so minimum, normal and maximum flow with their corresponding pressures. Oversizing is the most common mistake, because an oversized valve only controls in the first few degrees of travel and wears there rapidly. On pressure control valve we check that the actuator is sized on torque at maximum differential pressure and not on an average value. We never recommend a heavier execution of pressure control valve than needed, because over specification only raises price and lead time. On pressure control valve we also state what an execution cannot do, because that prevents more problems than a list of advantages. Where there is doubt about pressure control valve we quote two executions side by side, with the trade offs stated explicitly. During overhaul we measure trim and seat and advise whether reworking is sufficient or replacement works out cheaper. PRUSS builds control valves for the heavier end of this spectrum, with steam, high temperature and safety functions as its core territory. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. The right choice around pressure control valve starts with a full set of process data rather than with a request for a price. Where pressure control valve forms part of a safety function we record the fail position and required stroking time explicitly.

Pressure control valve supplied with technical advice

Dutch Valve Vision stays available after delivery of pressure control valve for technical questions and for parts. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion. We handle an enquiry for pressure control valve on its technical merits rather than as a price request that only produces a number. We think along on the spare parts strategy for pressure control valve, so critical positions stay covered. 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 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 record which execution of pressure control valve was delivered, so a follow up delivery or spare part matches exactly later on. Tests around pressure control valve are carried out by us or on our instruction according to the requirements in the specification. We keep the configuration data for pressure control valve on file, which saves a great deal of searching if a fault occurs later. For repeat orders of pressure control valve we record the configuration, so a follow up delivery is identical to the first. On pressure control valve we come back with a proposal that explains why we recommend a particular execution. 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 pressure control valve

What exactly does pressure control valve mean?

On gas and vapour service high pressure ratios produce noise and vibration, and a multistage trim is then used to divide the pressure drop. 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. 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. If you are unsure about this on pressure control valve, we are glad to put the question alongside the actual process data. On pressure control valve we prefer a well founded answer to a fast one that turns out to be wrong later. The subject of pressure control valve touches both the construction of the valve and the way the plant is operated. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion.

Which executions of pressure control valve are available?

Reducing and back pressure control are two different duties, and confusing them is a common specification error. During overhaul we measure trim and seat and advise whether reworking is sufficient or replacement works out cheaper. An equal percentage characteristic is used most often, because it largely compensates for the non linearity of the rest of the system. 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. On pressure control valve we include start up and shutdown, because that is where the heaviest loading occurs. We always explain why we arrive at a particular recommendation on pressure control valve, so you can follow the reasoning yourself. Operating conditions govern the service life of pressure control valve far more strongly than the nominal figures on a datasheet. 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.

Which materials are used for pressure control valve?

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. On liquid duty the risk is cavitation, and on gas duty the limiting factor becomes sound level and vibration. Rangeability states between which extremes the valve still controls reliably, and outside that band control becomes unstable. PRUSS builds control valves for the heavier end of this spectrum, with steam, high temperature and safety functions as its core territory. For pressure control valve a good specification up front is cheaper than a correction afterwards. Our experience with pressure control valve comes from projects in chemicals, power generation, technical gases and offshore. With pressure control valve it pays to include phase changes in the medium, because those sharply increase the load on the seal. 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 should I watch technically on pressure control valve?

Which applications call for pressure control valve?

What determines the price and lead time of pressure control valve?

A P&ID, a datasheet or even a photograph of the existing installation often helps us faster than a long description. For an accurate quotation we need the nominal diameter, the pressure class, the medium, the operating temperature and the required actuation. 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. The answer on pressure control valve depends strongly on operating conditions, which is why we always ask for those first. This is one of the points on pressure control valve where suppliers differ most clearly from one another. Our specialists are happy to discuss pressure control valve 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.

What about maintenance and spare parts on pressure control valve?

On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. On commissioning we record the settings and calibration, so a later fault can be traced. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. Documentation such as material certificates, test reports and declarations is supplied as standard, matched to what the project requires. The answer on pressure control valve depends strongly on operating conditions, which is why we always ask for those first. Our experience with pressure control valve comes from projects in chemicals, power generation, technical gases and offshore. Documentation on pressure control valve has to be the kind a buyer or inspector accepts without discussion. Alongside QUADAX and PRUSS we represent Pibiviesse, Schroeder, Striko, Malbranque, Daume, FluoroSeal and Guichon, so we can select the right brand for each project.

How do I request a quotation for pressure control valve?

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. We come back with a proposal that explains why we recommend a particular execution, including the alternatives we considered. 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. In most projects pressure control valve turns out to be less standard than it first appears. The answer to this question on pressure control valve changes as soon as the medium or the temperature changes. For pressure control valve you can come to Dutch Valve Vision for the selection, the delivery and the support afterwards. 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.