Valv Technologies - Model IsoTech -Parallel Slide Gate Seat-Protected Valve

IsoTech®, ValvTechnologies’ PSG valve addresses the need for true in line valve repairability in large diameter, high energy piping systems. Specifically designed for steam and feedwater applications, IsoTech® provides bi-directional, zero-leakage using our exclusive HVOF RiTech® process.

1. 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 dissassembly of the bonnet once the easy to extract segment rings have been removed.
2. 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.
3. 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.
4. Back seat area. The back seat is coated with chrome carbide (typical hardness 68-70 RC) and polished to achieve a bubble tight seal.

• Fully bi-directional isolation. Benefit: outstanding operating flexibility
• Long service life – sealing surfaces are overlaid with tungsten or chromium carbide cermets using our exclusive HVOF RiTech® process. Benefit: allows for exceptional resistance to attack by abrasives and fluids
• Stem, discs and guides overlaid with tungsten or chromium carbide cermets using our exclusive HVOF RiTech® process. Benefit: extra protection delivered
• The sealing surfaces are coated with chrome-carbide hardcoating to RC 72 hardness, then diamond lapped for a precision fit. Benefit: The exceptional hardness and temperature ratings to 1800°F make our valves extremely resistant to attach of abrasives and fluids, particularly steam and flashing water
• Designed for ease of maintenance. Benefit: The only requirement is for the disc to be flat against the seat. This is easily accomplished as there are no precise angles to maintain. Pressure seal bonnet has been designed to facilitate easy removal when necessary.
• Protected seats. Benefit: In the full open position, the flow through “conduit” is positioned precisely between the seats, eliminating turbulence and flow impingements on the seats. There is no gap between our conduit and the valve seat. Small gaps in our competitors’ valves cause extreme turbulence and in come cases cavitation.
• Self-cleaning. Benefit: Frequent valve usage polishes the surface for less torque and improved sealing. The high spring load insures contact throughout the stroke of the valve and prevents particulates migrating between the disc and seat also helps assist in the honing action.
• Various flow control options, including a v-port orifice. Benefit: This is ideal for warm-up and some bypass requirements
• Stem extensions. Benefit: Because of the low break-away and running torque, various stem extensions are available so that handwheels and actuators can be located remote from the valve
• Tight shutoff. Benefit: As a standard, ValvTechnologies meets zero-leakage requirements on low-pressure air and high-pressure water
• High spring load. Benefit: ValvTechnologies’ very high spring load not only assures contact between the gate and seat, but at all positions from open to close. This allows zero-leakage on hydrogen on vacuum.
• Parallel discs. Benefit: Unlike conventional designs where the discs are only parallel in the closed position, IsoTech® valves are designed to maintain its parallel discs from both the fully-open to the fully-closed position.
• Oversized stem diameter in comparison to other PSG designs along with or in combination with the tee-slot as opposed to a threaded and pinned hanger. Benefit: Increased reliability with this durable, robust design

• Various bypass configurations

• Main steam isolation
• Cold reheat isolation
• LP heater isolation
• HP heater isolation
• Feedwater isolation