How do you catch those unfit control valves during your project before it is too late? I mean too late before it really hurts! Before it eats your energy! Before it gives you sleepless nights! During my 42 years in the petrochemical industry, working 35 years for an American oil and gas major, I was often involved in large and mega projects as the automation engineer responsible for the engineering, commissioning and startup of instrumentation and control including those control valves.

Large capital projects in plant engineering come along with special challenges. It’s not unusual that starting up a plant for the first time and get it operating reliable causes reengineering and replacement of critical control valves and may lead to startup delays and significant operation loss in the early beginning of its live cycle. Applying new principles of operation for “Non Process Quality Control” (NPQC) show the way to a signi- ficant increase of quality in valve selection and reduction of cost for the plant operators at a very attractive cost benefit ratio.

I am ready to introduce a new CAT on the NPQC scene, with focus on control valves! If you don’t know what I am talking about? Then please read on and let me explain.

Prediction of regulation quality has recently repeatedly been the subject of discussion and debates, and it can be assumed that a practical and objective application guideline for regulation quality, orientated around the end-user's needs, will be presented during the further course of this year. With a view to efficient determination of the optimum valve configuration during the initial phase of design and valve selection, a static regulation quality index has been unveiled and implemented in CONVAL^® 8.0.

Prediction of regulation quality has recently repeatedly been the subject of discussion and debates, and it can be assumed that a practical and objective application guideline for regulation quality, orientated around the end-user's needs, will be presented during the further course of this year. With a view to efficient determination of the optimum valve configuration during the initial phase of design and valve selection, a static regulation quality index has been unveiled and implemented in CONVAL^® 8.0.

Interview with lead engineer for instrumentation and control Mr. Teun Hooftman.

The April 2005 issue of Valve World included an article looking at the 4000 control valves being specified for the massive Nanhai project in China. This follow-up article takes control a step further, looking at the 60-odd severe service control valves that have been specified.

The solutions were found with the help of CONVAL. 

This is the second and final section of Mr Siemers´ technical paper addressing plant design and control valve selection when working under increased time and cost pressure. The first section (April issue) focused on control valve operating points and provided a case history involving a mismatch before introducing better valve sizing practices.

Following a career spanning three decades, Mr Siemers is well aware of the pitfalls to be avoided when specifying control valves for a range of demanding applications.

In his latest paper for Valve World, he looks further into plant design and control valve selection when working under increased time and cost pressure. This article is split into two parts: broadly speaking, part one looks at control valve operating points and provides a case history involving a mismatch.

This final section of Mr Holger Siemers article on control valve design and sizing continues on from part I+II, which can be found in the June and August 2004 issue of Valve World.

This second section of Mr Holger Siemers article on control valve design and sizing continues on from part I, which can be found in the June 2004 issue of Valve World. This section presents information on design, size and use of severe service control valves, the kind of troubles that can be predicted with control valve sizing as well as suggestions for troubleshooting control valve failures. The final section, part III, will be ready and waiting in the upcoming October issue.

With three decades of experience in demanding applications, Mr Siemers has a deep appreciation of developments and trends in sizing control valves. In this paper, he reviews the past, present and future of valve design and sizing, taking all-important issues such as increasing cost pressure and time pressure into account. This paper is presented in two parts: firstly, how to use manufacturer independent software to analyze given or calculated plant parameters in more detail from an overall point of view with a complete power check and optimizing possibilities.

Seit langem schon gibt es herstellerspezifische wie auch unabhängige Softwarelösungen, um verschiedenste Arten von Stellventilen auszulegen und zu optimieren.

CONVAL^® hat bisher das Spektrum vom Hubventil über Klappen und Kugelhähne bis hin zum Membranventil mit allen nötigen Zusatzberechnungen abgedeckt.

The fact that fluid properties are unknown and typical values for ideal gases are assumed by way of approximation frequently results in the over dimensioning of actuation systems for high differential pressure systems.

The isentropic exponent (kappa) and the valve factor xT can, in particular, have an enormous influence on the coefficient of flow K_v needed. The use of CONVAL^® 5.0 software for design with integrated thermodynamic physical data computation and a valve database virtually eliminates such errors.

This article describes CONVAL^® 5 for Windows, which was recently launched in the marketplace following a development phase lasting several years. It begins by demonstrating typical problems relating to time-critical plant design, focusing particularly on the plant and control valve parameter "dynamic pressure ratio" (dp100/dp0) and continuous valve characteristics between linear and equal-percentage.

Plant structures often contain a large number of components that have to be designed and calculated precisely. CONVAL^® is a software package which is intended to simplify the work of plant operators and planners. Its potential range of applications is examined here with reference to a practical example.