RZD-X, axial shutoff valve, 2″–72″, ASME 150–2500 / API 3000–10 000

Description

The RZD-X axial shutoff valve with a balanced piston is designed for special and critical duties in the gas and oil industry. The manufacturer offers it in place of ball valves, plug valves and gate valves where fast action, tightness and operation in severe conditions are required. Typical installation points are fast shutoff valves of high integrity pressure protection systems (HIPPS) and emergency shutdown systems (ESD), severe-service isolation in the field, flowlines and manifolds, critical equipment isolation, and start-up and blow-down at compressor stations and gas distribution stations.

All of the manufacturer's valves work on the Axial Flow principle, in use since 1955. Between the inner and outer body lies a streamlined symmetrical annular channel without sharp turns of the flow. The Total Velocity Management® concept controls the velocity of the medium in all zones of the valve and eliminates local high velocities, the main cause of noise, erosion and vibration. The full-bore enlarged body creates practically no pressure loss, so the operating costs of pumps and compressors are reduced. The one-piece cast body is 15–60 % lighter than a ball valve or gate valve, especially in combination with compact spring-return actuators.

The valve is pressure-balanced: the medium acts on both sides of the piston and stem, so the stroking force is small, constant and independent of pressure. It opens at full differential pressure without damage to the seals and without a bypass for equalisation, and it does not stick when used rarely. The low mass of the moving parts gives very fast travel; for example, a 20″ Class 1500 valve closes in less than 2 seconds. The self-sealing system of two high-pressure rings and a spring in the piston gives bidirectional bubble-tight Class VI shutoff at any differential pressure. In the open position the main seal is hidden in the piston head and is not exposed to erosive flow. The seals are located inside the body, so external heating has little effect on them, and all shutoff valves are certified as fire-safe.

Sizes are 2″–72″, pressure classes ASME 150–2500 or API 3000–10 000, higher classes are made on request. Low emission Class B per ISO 15848-1 is available as an option. The valve is designed for the specific duty and equipped with the manufacturer's pneumatic or hydraulic actuators with an individual control scheme, as well as electric or electro-hydraulic actuators. Axial shutoff valves are also used on hydrogen and syngas.

Technical specifications

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