The Arca Multi stage angle style control valve type 350 and 380 are proven under critical process conditions for a long time. If used in steam or process gas applications at high pressure and temperature, in cavitation-free relaxation of liquids at high pressure differential or in handling of forces fluids with high solid contents; the modular system of valve housings, bonnet and trim styles, in combination with a large range of materials, always offer an ideal solution.
The combination of high pressure ratio and solid-containing fluids is one of the most critical challenges for sizing, selection and design of a control valve.
Due to the high pressure ration multi-stage valves indispensable to avoid severe cavitation damages; however as soon as the fluid contains solid particles besides the normal fluid-dynamic sizing (determination of the number of throttling stages and their individual flow coefficient), the grain size of the particles has to be taken into account. The cross-section area of each flow channel in the valve must be that size and shape, which allow all particles in the fluid (assumed to be of spherical shape) to pass.
Since the cross section area if each throttling stage is explicit defined by the flow coefficient calculated form the fluid-dynamic valve sizing, only the shape of the flow channel remains to optimize.
It is obvious, that a circular shape is the optimum with regard to the permeability of spherical particles. The new-developed multistage trim MS4, which has only one flow channel each stage, milled as a spherical calotte into a rigid, multiple guided control rod, approximates this ideal shape in ideally way and is superior to any multistage parabolic plug in this point of view.
Another special feature of this trim style is the protection of the seating surface (which is the most sensible area in terms of erosion) by overstroke of the valve. With this, the control stages of the valve will open only as soon as a low pressure differential and with this a low small flow velocity at the seating surface is maintained.
The rigid multiple guidance of the control rod is an effective prevention of the valve against mechanical vibrations and the resulting wear, even at extremely high pressure differentials.
The multi stage angle style control valve Series 350 and 380 are available in sizes up to 10” (DN 250) and ratings up to Class 2500 (PN 400). Depending on the process conditions, MS4 trims can be delivered in valve sizes up to 4” (DN 100).