VALVES MEET THE UNIQUE CHALLENGES OF HYDROCARBON PROCESSING

John Middleton 15/01/2008

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Process Control Valves

Hydrocarbon processing applications place unique and challenging demands on in-line components, such as valves and other associated control devices. Valve specialists SAMSON CONTROLS have used their extensive engineering experience to develop a range of modular control valves which can be tailored to the individual requirements of an application and therefore meet the challenges faced in most hydrocarbon processing applications.

Samson control valves are available in globe, angle and three-way body styles, in all common pressure ratings and in all common materials to enable optimum application flexibility. Their 240 and 250 series of valves are designed to conform with ANSI, DIN and JIS standards and can be combined with various flange styles and butt-weld ends. Pneumatic actuators with a rolling diaphragm and springs evenly arranged in the actuator case are made to precisely fit on valves over robust yokes to ensure a compact and integral control valve package.

In certain pressure reducing applications, such as those involving gases and vapours, the demands placed upon valves can reach optimum levels. For example, the medium expands as it passes through the control valve, its velocity increases rapidly, even at small pressure drops and this creates turbulence with high pressure fluctuations at the valve exit. As the pressure difference rises, the flow velocity increases, exceeding the speed of sound, while the turbulence is overlapped by shock waves.

This phenomenon exposes valve components to extreme stress and leads to vibration and noise emissions which can exceed 100 dB(A). As a result of extensive testing to investigate how noise develops in control valves and to find ways of optimizing noise behaviour patterns, Samson have developed valves which ensure a low-noise pressure letdown by restricting the velocity at the valve outlet to 0.3 Mach. The valve design means secondary noise levels are avoided, while the Samson flow divider keeps the turbulent zone directly downstream of the valve restriction under control, resulting in a reduction of noise level by as much as 30 dB(A).

With a wide ranging product line, well suited to handling corrosive and erosive media, high pressure drops and extreme operating temperatures are safely controlled. Long lasting, highly efficient sealing techniques allow installation of Samson equipment in extreme applications and therefore prevent environmentally damaging emissions.

Foe more information contact Samson Controls (London) Ltd, Redhill, Surrey,

Tel: 01737 766391 Fax: 01737 765472

E-mail: Sales@samsoncontrols.co.uk Web: www.samsoncontrols.co.uk