THE characterised seat control valve from Worcestor Controls is a ball valve, but that is where the similarity ends. The throttling part of the valve is based on a patented seat technology consisting of a standard sintered stainless steel seat, impregnated throughout with TFE or graphite, that is laser cut to provide state of the art modulating control.
Worcester's advanced valve technology, available from Invensys Flow Control , gives a high pressure drop capability with straight through flow, precision control, shearing action, erosion control and bubbletight shut off.
The technology is a self lubricating, full contact seat of sintered stainless steel. The flow characteristic is laser cut to a "V" shape, slots or customised shapes to meet any control requirement.
The controlling element is a super round, hard nickel coated ball with a round resilient or sintered stainless steel seat on the opposite side. The lubricating action of the special coating of the ball and the impregnation of the characterised seat results in a smooth, stable and precise throttling action.
The characterised seat design allows the use of exotic materials such as Inconel 600, Hastelloy C22, Monel or the ceramic Zirconia. The seat design allows pressure drops to 35 bar for liquids and 20 bar for steam while the floating ball and second resilient seat provides a bidirectional control valve that will give bubbletight shutoff.
Variations in the characterised seat design provides an inherent equal percentage flow characteristic for the "V" shape seat, slotted seats provide an inherent linear characteristic while multiple port seats and seats with custom openings are available to meet customers individual requirements.
Standard seat Cv values range from .02 in a 25mm valve to 580 in 100mm valve. The valve configuration is available in 3-piece, wafer and flanged ANSI class 150# and 300# designs.