Special valves examined up close
Special valves fall outside the standard catalogue range and are built for media, temperatures, pressures or certification requirements that ordinary industrial valves do not cover. Anyone looking into special valves quickly runs into a choice that goes beyond picking a catalogue number. It pays to understand the working principle behind special valves first, because the limits follow from that principle. When an original type is no longer available we look for a technically equivalent replacement with the same installation dimensions. During overhaul we first assess whether reworking the seat and disc is sufficient, because that is almost always faster and cheaper than replacement. For spare parts we work from the original configuration, for which a tag plate or serial number is usually enough. For special valves this means that construction and operating conditions cannot be judged separately. The balance between required tightness and available operating force is a recurring tension on special valves. A correct execution of special valves accounts for real operating conditions and not only for design values. Tests such as a pressure test, a tightness test, a low temperature test or an emission test are carried out by us or on our instruction to the project requirement. We assemble valve and actuator together, set them and test them, so the delivery arrives as one working unit. We find that questions about special valves almost always come back to the same three points: medium, temperature and required tightness.
What to watch technically on special valves
The specials market exists because standard products are optimised for the average case, and industry is full of cases that are not average. We regularly see that a small change in the execution of special valves makes a large difference to maintenance frequency. What weighs heaviest on special valves in practice is the combination of temperature and differential pressure, not either one alone. A special valve normally starts from a proven construction, which keeps risk and lead time under control. A special valve is often a standard construction with an adapted material, an adapted seat or a different connection. We supply maintenance and overhaul kits composed for the specific valve, rather than loose parts that turn out not to fit. For us bespoke work does not start with a drawing but with the question of what exactly is going wrong or missing in the plant. The real value sits in the selection work, because choosing wrongly in this segment is expensive in both money and downtime. A tag plate with project data is supplied as standard where the project requires it. Dutch Valve Vision works under a KIWA ISO 9001 certified system, which safeguards traceability on bespoke work. Operating conditions govern the service life of special valves far more strongly than the nominal figures on a datasheet. With special valves it pays to include phase changes in the medium, because those sharply increase the load on the seal.
Applications of special valves in industry
We see specials mainly in chemicals, technical gases, offshore, power generation and hydrogen projects. Our bespoke enquiries come mainly from chemicals, power generation, offshore and from hydrogen and ammonia projects. In existing plants the question is often replacement within existing dimensions, and that is exactly where bespoke work pays for itself. We supply special valves both for new build and for replacement within existing installations. Our customers use special valves in positions where a failure has immediate consequences for production. The application range of special valves runs from simple utility duty to heavy process plant, with a corresponding difference in execution. In plants where special valves is applied, the emphasis is on reliability rather than lowest purchase price. During turnarounds we work to tight schedules, and then predictability matters more than the lowest price. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users. Demand for special valves reaches us mainly from projects where the standard range falls short. During turnarounds special valves is regularly on the critical path, and then predictability matters more than the lowest price.
How to select special valves without mistakes
The right choice around special valves starts with a full set of process data rather than with a request for a price. A non standard face to face length or flange standard is usually solvable without modifying the pipework, and that saves considerably. We say honestly when a modification is not technically or economically sensible, even when that costs us the order. For projects with many positions we build a configuration overview, so it stays clear later which execution sits in which position. The cleaning and flushing procedure counts too on special valves, because it can be more aggressive than the process itself. For special valves total cost of ownership weighs more than purchase price, certainly when replacement has to happen during a shutdown. Standardising across several positions makes special valves simpler in maintenance and in spare parts management. On special valves we check that the actuator is sized on torque at maximum differential pressure and not on an average value. We are happy to think along on a spare parts strategy, so critical positions are covered without carrying redundant stock. We document exactly what has been supplied, including material certificates and test reports, because that saves time on a later fault. If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. We never recommend a heavier execution of special valves than needed, because over specification only raises price and lead time.
Dutch Valve Vision as your supplier of special valves
We think along on the spare parts strategy for special valves, so critical positions stay covered. 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. On special valves we come back with a proposal that explains why we recommend a particular execution. We supply special valves as a loose product or as a fully assembled unit with actuator and accessories. 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. Documentation on special valves has to be the kind a buyer or inspector accepts without discussion. A tag plate with project data belongs with special valves as standard where the project requires it. On special valves we make sure the chosen execution demonstrably meets the stated standards rather than merely looking plausible on paper. We handle an enquiry for special valves on its technical merits rather than as a price request that only produces a number. Dutch Valve Vision stays available after delivery of special valves for technical questions and for parts. 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 special valves
What exactly does special valves mean?
A special valve is often a standard construction with an adapted material, an adapted seat or a different connection. For spare parts we work from the original configuration, for which a tag plate or serial number is usually enough. For us bespoke work does not start with a drawing but with the question of what exactly is going wrong or missing in the plant. Special valves fall outside the standard catalogue range and are built for media, temperatures, pressures or certification requirements that ordinary industrial valves do not cover. We always explain why we arrive at a particular recommendation on special valves, so you can follow the reasoning yourself. We see this come back regularly in enquiries about special valves, and the answer is rarely a single sentence. The subject of special valves touches both the construction of the valve and the way the plant is operated. 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 executions of special valves are available?
We supply maintenance and overhaul kits composed for the specific valve, rather than loose parts that turn out not to fit. Dutch Valve Vision works under a KIWA ISO 9001 certified system, which safeguards traceability on bespoke work. We document exactly what has been supplied, including material certificates and test reports, because that saves time on a later fault. A tag plate with project data is supplied as standard where the project requires it. On special valves we prefer a well founded answer to a fast one that turns out to be wrong later. Our experience with special valves comes from projects in chemicals, power generation, technical gases and offshore. On special valves we always check the full operating envelope, including start up and shutdown. 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 materials are used for special valves?
When an original type is no longer available we look for a technically equivalent replacement with the same installation dimensions. A special valve normally starts from a proven construction, which keeps risk and lead time under control. We are happy to think along on a spare parts strategy, so critical positions are covered without carrying redundant stock. Tests such as a pressure test, a tightness test, a low temperature test or an emission test are carried out by us or on our instruction to the project requirement. In most projects special valves turns out to be less standard than it first appears. The answer on special valves depends strongly on operating conditions, which is why we always ask for those first. How special valves behaves under varying load says more about the quality of the selection than behaviour under steady load. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects.
What should I watch technically on special valves?
What should I watch technically on special valves?
Which applications call for special valves?
Our bespoke enquiries come mainly from chemicals, power generation, offshore and from hydrogen and ammonia projects. During turnarounds we work to tight schedules, and then predictability matters more than the lowest price. We see specials mainly in chemicals, technical gases, offshore, power generation and hydrogen projects. In existing plants the question is often replacement within existing dimensions, and that is exactly where bespoke work pays for itself. That makes special valves a subject where discussion up front pays for itself in operation. The answer to this question on special valves changes as soon as the medium or the temperature changes. On replacement we always check the existing installation dimensions for special valves, so the pipework can stay untouched. 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 determines the price and lead time of special valves?
On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. 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. 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 special valves we include start up and shutdown, because that is where the heaviest loading occurs. This is one of the points on special valves where suppliers differ most clearly from one another. Even when the specification for special valves is not yet finalised, you can bring the question to us. 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 special 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. 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. A tag plate with project data is supplied as standard where the project requires it. We are happy to think along on a spare parts strategy, so critical positions are covered without carrying redundant stock. That makes special valves a subject where discussion up front pays for itself in operation. If you are unsure about this on special valves, we are glad to put the question alongside the actual process data. We work on special valves under a KIWA ISO 9001 certified quality system, which safeguards traceability. 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.
How do I request a quotation for special valves?
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. 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. We always explain why we arrive at a particular recommendation on special valves, so you can follow the reasoning yourself. If you are unsure about this on special valves, we are glad to put the question alongside the actual process data. Our specialists are happy to discuss special valves 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.