Why Valtech?

The body and bonnet are cast with uniform section and generous radius fillets to prevent stress concentration. The castings are precision-machined for high performance. The gate valve body has a straight through port without recesses except at the seat area. This ensures minimum turbulence, erosion and resistance to flow. Long integral guide ribs in the body match with guide slots in the wedge for accurate alignment and guidance. Bonnet castings are of one-piece design, where the yoke is integral with the bonnet for gate valves of sizes up to 12″ (300mm). This ensures accurate alignment of stem and a smooth operation.

In globe valves of larger sizes and for higher pressure classes of ASME Class 900 and above, the internal part of the body is machined to provide continuous guiding of the disc from the open to the closed position. The check valve body provides a full port without pockets from inlet to the valve seat. On the downstream side, the body has generous proportions to facilitate full swing of the disc to reduce disc erosion and flow resistance.

VALTECH gate valves feature a one-piece cast flexible wedge that minimises stress concentration. Wedge flexibility ensures tight seating over a wide range of differential pressures and temperatures. It also adjusts to slight misalignments caused by pipeline deflections and thermal deformation. The stem-to-wedge thrust is applied close to the wedge centre. This reduces lateral stem loading and provides for more accurate wedge movement.

VALTECH globe valves feature a ball-type disc that provides a fine grain surface on the taper seat. For severe services that demand hard-faced seats, a plug-type disc is provided.

The one-piece construction is securely fastened to the hinge by means of a lock nut and pin. The disc is free to rotate to avoid localized wear. The hinge pin offers excellent wear resistance properties.

VALTECH gate valves and check valves feature a seal-welded seat ring that offers a leakproof design as it eliminates the leakage path betwen the seat ring and the body. This design is superior to screwed seats which can loosen up due to temperature fluctuations, corrosion or vibration and result in leakage. For 50mm gate valves, the seat ring is flared into the body, while seal welding is optional.

VALTECH globe valves feature a shoulder type, threaded body seat ring which has a wide taper area that provides for ample seating. Slots on the seat ring allow easy in-situ removal for servicing. Threaded seat rings are secured by a tab-weld. Welded seat rings are also availble in VALTECH Globe Valves.

VALTECH gate and globe valves feature a stem of one-piece construction, ACME threaded and precision-machined with polished surfaces to reduce friction, minimise leakage and extend stem life.

In gate valves, the heavy forged T-head engages with the T-slot in the wedge. The stem also has an integral self-adjusting radial back-seat shoulder that matches with the back-seat bush in the bonnet.

In globe valves, the stem is held to the disc by a stem nut that permits the disc to swivel. This free-floating design ensures uniform seating.

The standard range of VALTECH flanged valves in sizes of up to 24″ (600mm) is finished with end-flanges faced, drilled and spot-faced (or backfaced) to ASME B16.5 Raised Face (RF). Flanges in valves of sizes larger than 24″ (600mm) are drilled as per ASME B16.47 Series A (MSS SP 44) or Series B (API 605). Valves in ASME Class 600 and above are offered with RTJ end flanges on request. The standard finish offered on the raised faces is 125-250 microns in Ra (AARH) Spiral Serration. Other finishes can be offered on request.