LESER Type 441/442 ANSI High Performance Safety Valve
Overview
The LESER Type 441/442 ANSI is the ASME-flanged member of LESER’s High Performance safety valve series, built to the same proven rolled-in-seat, full-lift architecture as the DIN version but dimensioned to ASME B16.5 flange standards for plants running on American and international ASME piping codes. Covering NPS 3/4 through NPS 16 with flow diameters from 23 mm to 295 mm, the Type 441/442 ANSI gives specifying engineers a single, broadly certified valve platform for steam, gas, and liquid overpressure protection across process units, utilities, and rotating equipment packages.
With engineering support in Muscat, Seven Star LLC supplies the Type 441/442 ANSI on request to EPC contractors, refineries, and gas plants across Oman and the wider GCC. Facilities in Muscat, Sohar, and Salalah that specify equipment to ASME/API codes rely on Seven Star LLC for genuine LESER hardware, ASME UV-stamped documentation, and local application engineering support for correct sizing on new-build and revamp projects.
Operating Principle
Like all LESER High Performance valves, the Type 441/442 ANSI is a direct spring-loaded, full-lift safety valve. System pressure acting on the disc through the rolled-in seat is balanced against a calibrated spring force; once the set pressure is reached, the disc lifts rapidly to full travel and the valve discharges at its rated capacity until pressure drops to the reseating point. This snap-action, full-lift behaviour keeps overpressure accumulation within about 5% of set pressure, well inside the margins required by ASME Section I and Section VIII pressure-relief rules.
The valve’s mechanical, spring-actuated operation means it requires no external power source, control signal, or instrument air supply to function, so it remains available exactly when a plant upset or utility failure creates the overpressure event it is meant to relieve. Trim materials and seat geometry are selected to resist wire-drawing across repeated cycles, and the spring housing is sized to keep the spring within its rated temperature envelope across the full -268°C to 538°C ASME temperature range, preserving long-term set-pressure stability.
Engineering Design of the LESER Type 441/442 ANSI
The LESER Type 441/442 ANSI body is cast in carbon steel (material 1.0619 / SA216 WCB) or stainless steel (1.4408 / SA351 CF8M), giving a straightforward choice between general process service and corrosion-resistant applications without changing the valve’s external footprint. ASME B16.5 flange connections in Class 150 through Class 300 mate directly with standard American piping, and orifice sizes F through X provide flow areas from 416 mm² up to 68,347 mm², covering everything from small relief lines to large vessel and compressor discharge protection within a single product family.
The LESER Type 441/442 ANSI mounts in standard vertical inline flanged configuration, with an open bonnet and accessible spring housing that allows technicians to verify set pressure and inspect the seat without a full teardown in most service scenarios. Optional lifting levers support code-mandated manual operability checks, and bellows or open bonnet variants extend the base casting into back-pressure-compensated or atmospheric discharge applications, letting one core design serve a wide span of plant configurations.
Key Features
Engineers standardizing on the LESER Type 441/442 ANSI for ASME-flanged safety valve service benefit from the Type 441/442 ANSI’s broad coverage and certification base. Highlights include:
- ASME B16.5 flanged connections from NPS 3/4 to NPS 16 in Class 150 through Class 300.
- Set pressure range of 0.1 to 49 bar (CE) or 1 to 49.3 bar (ASME), covering the majority of process and utility relief duties.
- Temperature capability from -270°C to 450°C (CE) and -268°C to 538°C (ASME), spanning cryogenic to high-temperature steam.
- Body material options of SA216 WCB carbon steel or SA351 CF8M stainless steel to match media and corrosion requirements.
- Orifice sizes F through X with flow diameters of 23–295 mm and flow areas of 416–68,347 mm².
- Full-lift, rolled-in-seat design that opens rapidly to rated capacity and reseats within a tight blow-down band.
- Broad third-party approvals including ASME, CE, VdTÜV, CRN, EAC, TS, UKCA, and marine classification societies.
- Standard delivery of roughly two weeks for common configurations, supporting fast-track turnaround and new-build schedules.
Industrial Applications
The LESER Type 441/442 ANSI is specified wherever plant design follows ASME B16.5 piping and flange standards, including refineries, gas processing trains, petrochemical units, and power generation facilities running on steam, air, non-corrosive gas, or liquid media. Typical duties include compressor and pump discharge protection, pressure vessel and heat exchanger relief, utility steam and condensate systems, and general process piping across oil and gas, LNG support facilities, desalination plants, and district cooling networks that specify equipment to American engineering standards.
Backed by genuine manufacturer documentation, Seven Star LLC supplies the Type 441/442 ANSI throughout Oman and the GCC, supporting ASME-code projects in the Sohar and Salalah industrial and free zones as well as EPC-managed developments across Muscat and the wider Sultanate of Oman. Project teams sourcing safety valves for ASME-stamped packages work directly with Seven Star LLC’s instrumentation division for sizing, documentation, and supply.
Technical Specifications
Key parameters for the LESER Type 441/442 ANSI High Performance safety valve, the LESER Type 441/442 ANSI, are summarized below for specifying engineers.
| Parameter | Specification |
|---|---|
| Model | LESER Type 441/442 ANSI |
| Connection Standard | ASME B16.5 flanged |
| Size Range | NPS 3/4 to NPS 16 |
| Flange Class | Class 150 to Class 300 |
| Set Pressure (CE) | 0.1 – 49 bar |
| Set Pressure (ASME) | 1 – 49.3 bar |
| Temperature (CE) | -270°C to 450°C |
| Temperature (ASME) | -268°C to 538°C |
| Orifice Range | F through X |
| Flow Diameter | 23 – 295 mm |
| Body Materials | 1.0619 / SA216 WCB carbon steel, 1.4408 / SA351 CF8M stainless steel |
| Media | Steam, gas, liquid |
| Approvals | ASME, CE, VdTÜV, CRN, EAC, TS, UKCA, DNV, ABS, Lloyd’s Register |
Request a Quote for LESER Type 441/442 ANSI
Seven Star LLC’s instrumentation division is ready to prepare a formal RFQ for the LESER Type 441/442 ANSI, with lead time confirmed at quotation for demanding ASME-code project schedules. Technical datasheets, ASME UV documentation, and ValveStar sizing assistance are available on request, and as an experienced supply partner for LESER in Oman and the GCC, Seven Star LLC guarantees genuine product, full traceability, and manufacturer-backed warranty on every valve supplied. Contact our team today to specify the correct LESER Type 441/442 ANSI configuration for your project.
Browse the full LESER range or see more Safety Relief Valves products supplied by Seven Star LLC in Oman and the GCC.
- Datasheet LESER Type 441/442 Datasheet Download
LESER safety valve product groups
LESER sorts its valves into named groups, and the type number identifies the design:- API: Type 526 flanged safety relief valves to API 526 dimensions
- High Performance: Type 441/442 flanged valves, and Type 455/456 and 457/458 for high pressure
- Compact Performance: threaded Types 437, 459 and 462
- High Efficiency: pilot-operated safety valves such as the pop action Type 811
- Critical Service: Types 447 and 449 for corrosive media, the 447 with PTFE-lined wetted parts
- Clean Service: hygienic valves for food and pharmaceutical plants
Where LESER safety valves are used
LESER safety valves protect pressure vessels, heat exchangers, boilers, compressors, pumps and piping against overpressure in oil and gas, refining, petrochemical, power, industrial gas, food and pharmaceutical plants throughout the GCC. Spring-loaded valves are the standard choice. Pilot-operated valves are selected where operating pressure runs close to set pressure or back pressure is high.Ordering LESER valves: what we need
A safety valve is always built to a set pressure, so a type number alone cannot be quoted. Please send the nameplate data of the existing valve (type, article or job number, serial number, set pressure, orifice) or a full data sheet: medium and its state, set pressure, operating and relieving temperature, back pressure, required capacity, inlet and outlet size and rating, body and trim material, design code (ASME Section VIII or PED) and options such as bellows, lifting lever or sour service materials. We verify the selection against LESER documentation and supply the manufacturer's certificates on request.Browse LESER products by category: Safety Relief Valves.
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