Axial on-off Valve

• Type designation: Safety shutdown valve or isolating valve
• Model: RZD - X
• Scope:
• Sizes: 2" - 72"
• Ratings: ASME 150 - 2500 or API 3000 - 10 000
• Higher pressure ratings upon request
• In preference to:
• Ball valve
• Plug valve
• Gate valve
• Typical applications:
• Severe-duty on-off (upstream)
• Quick-acting on-off (HIPPS)
• Flow line and header on-off
• Critical isolation, start-up and blow-down

Axial flow 
Streamlined flow path through the full-port expanded body avoids turbulence and prevents erosion and vibration. Process downtime and maintenance costs are reduced.

Low pressure loss 
The capacity of the axial on-off valve is extremely high, as a result of which the pressure loss is negligible. Operating costs of pumps and compressors are reduced.

Pressure balanced 
Operating forces are independent of pressure. Valve can be opened against full differential pressure without damage to sealing. Equalisation with a bypass valve is not required.

Easy actuation 
Actuation force is low and constant because of pressure-balanced trim. Small, spring-opposed actuators can be selected and gearboxes are not required.

Excellent sealing 
In the open position the main seal is protected against erosive flow. The self-energising sealing system offers reliable bi-directional and bubble-tight shut-off (class VI).

Compact 
The one-piece valve body provides 15-60% weight reduction compared with ball or gate valves. This benefit is even more attractive combined with spring-opposed actuators.

Fire-safe 
The seals that prevent internal and external leakage are secured inside the valve body and therefore less susceptible to external heat sources. All axial on-off valves are certified fire-safe.

Special features

• Custom-designed
• Safety: secured process isolation by means of reliable on-off technology (HIPPS)
• Very fast stroke times : 20” Class 1500 in less than 2 seconds.
• Suitable for infrequent use: operating forces do not increase over time. No-sticking.
• Full range of matching Mokveld pneumatic and hydraulic actuators with tailored control arrangements is available. Electric and electro-hydraulic actuation is also available.