The LESER Type 431/433 Modulate Action Safety Relief Valves are engineered for reliable pressure protection across a wide range of industrial applications. Designed to handle steam, gases, and liquids, these valves feature a proportional opening characteristic, minimizing medium loss and ensuring stable operation, particularly for medium mass flows.
Parameter | Type 431/433 | Type 431/433 PN 160 |
---|---|---|
Set Pressure | 0.2–40 bar (2.9–580 psig) | 0.3–160 bar (4.35–2321 psig) |
Temperature Range | -270°C to 450°C (-454°F to 842°F) | -270°C to 450°C (-454°F to 842°F) |
Nominal Diameter at Inlet | DN 15–DN 150 (NPS 1/2–NPS 6) | DN 15 (NPS 1/2) |
Actual Orifice Diameter (d₀) | 12–92 mm (0.47–3.62 in) | 12 mm (0.47 in) |
Actual Orifice Area (A₀) | 113–6648 mm² (0.175–10.3 in²) | 113 mm² (0.175 in²) |
Flange Rating Inlet | PN 16–PN 40, ASME Class 150–300 | PN 63–PN 160, ASME Class 300–600 |
Body Material | 0.6025, 0.7043, 1.0619, 1.4408 (Gr. 60-40-18, SA 216 WCB, SA 351 CF8M) | 1.0619, 1.4408 (SA 216 WCB, SA 351 CF8M) |
Bellows Material (Optional) | Stainless steel, elastomer | Stainless steel |
Seat Gasket | Metallic, sealing plate, O-ring | Metallic, sealing plate, O-ring |
Load Type | Spring-loaded | Spring-loaded |
The LESER Type 431/433 valves are designed for reliable pressure relief in various industries:
These valves are suitable for steam, gases, and liquids, per AD 2000-Merkblatt A2 standards.
Yes, the PN 160 variant supports pressures up to 160 bar (2321 psig).
They are certified to PED, AD 2000-Merkblatt A2, AQSIQ, EAC, and classification societies like LR, RINA, and DNV GL.
Yes, options include O-ring soft seals, bellows, and metallic sealing plates for specific applications.
The self-draining angle-type body and single-part spindle design reduce residue and corrosion.
For more information about the LESER Type 431/433 Safety Relief Valves, pricing, or to request a demo, contact our team: