_{Henk Hinssen, iHandle Engineering bvba}

_{Henk Hinssen, iHandle Engineering bvba}

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. 

_{David Sear, Editor-in-Chief, Valve World Magazine}

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.

Part two starts by explaining the trends and definitions of inherent valve characteristics before focusing on "quick and dirty" sizing. The paper then addresses cavitation before concluding with the expert software available to help select the optimum valve characteristic form.

_{Dipl. Ing. Holger Siemers, SAMSON AG}

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.

The author then introduces better valve sizing practices and uses this theory to resolve the problems introduced in the case history. Part two (scheduled for the June issue) starts by explaining the trends and definitions of inherent valve characteristics before focusing on „quick and dirty" sizing.

The paper then addresses cavitation before concluding with the expert software CONVAL to help select the optimum valve characteristic form.

_{Dipl. Ing. Holger Siemers, SAMSON AG}

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.

_{Dipl. Ing. Holger Siemers, SAMSON AG}

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.

_{Dipl. Ing. Holger Siemers, SAMSON AG}

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. Some case studies are also discussed. The second section, scheduled for a future issue, includes information on to design, size and use severe service control valves with good performance for long maintenance intervals. Different philosophies of valve design (plug design), pressure balance systems, stem sealing, actuator sizing, cost philosophies for "high end" applications are discussed.

_{Dipl. Ing. Holger Siemers, SAMSON AG}

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.

Im kommenden Release 6.0 wird das Paket unter anderem auch durch Optionen zum Auslegen von Dampfumformventilen und dem dazugehörigen Einspritzventil erweitert.

_{Andreas Vogt, F.I.R.S.T. GmbH}

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.

_{Andreas Vogt, F.I.R.S.T. GmbH}

_{Andreas Vogt, F.I.R.S.T. GmbH}

_{Dipl. Ing. Holger Siemers, SAMSON AG}