VALVETECHNOLOGIES
ISOTECH® – PARALLEL SLIDE GATE SEAT-PROTECTED VALVES
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✔︎ Bonnet area: The pressure seal bonnet has been designed with a graphite composite seal. The bonnet has sufficient mechanical bolting to ensure the seal does not relax during periods when the system is not pressurized. In addition to the high reliability of the seal, the bonnet area has been designed to minimize the problems associated with maintenance on large gate valves. The valve has been designed so that the bonnet does not have to be forced in to the valve bonnet throat to allow for the segment rings to be removed. The large bolting used to ensure that the pressure seal is always loaded has also been utilized to enable simple disassembly of the bonnet once the easy to extract segment rings have been removed.
✔︎ Gland area: The gland is the same standard design employed throughout ValvTechnologies’ various valve product lines. The stem and gland are hardfaced and polished. The packing has 316 SS woven wire mesh anti-extrusion rings top and bottom and grafoil center ring. This is combined with our proven, superior, multiple Belleville® spring stacks, live loaded stuffing box. The gland design completes the superb proven pedigree of this valve range.
✔︎ Disc and seat area: The valve discs and seats have been overlaid with the same carbide overlay (68-70 RC) as its counterpart, the ValvTechnologies’ metal seated ball valve. These seats are several magnitudes harder than Stellite 6, typically (34-38 RC) and are lapped to achieve a bubble-tight seal under all pressure conditions, including vacuum. The large spring load ensures a high initial seal, and the line pressure increases the sealing. The web guide (which is also carbide overlayed) ensures the discs are kept parallel, whether the valve is in the open or closed position. This overcomes a common gate valve problem. As the valve is cycled under differential pressure, the extremely hard surfaces continually hone and polish each other instead of scratching and galling. The seal is improved rather than degraded with wear/use.
✔︎ Back seat area: The back seat is coated with chrome carbide (typical hardness 68-70 RC) and polished to achieve a bubble-tight seal.
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➤ Sizes → 4-36”
➤ Pressure Class → ASME / ANSI Class 600 – 4500
➤ Materials of Construction → Carbon steel (A216 WCB) – standard, Alloy steel (A217 WC9, A217 C12A) – standard, Stainless steel (A351 CF8M) – standard, Duplex steel, Exotic alloys, Other materials available upon request
➤ In Compliance → ASME B16.34, PED, Nuclear ASME III Class 1, 2 and 3, Nuclear Safety Related – 10CFR50 Appendix B, SIL
➤ End Connections → Buttweld – standard, Other end connections available upon request
➤ Shutoff → Bi-directional, zero-leakage shutoff