Spring Loaded Full-Lift Safety & Pressure Relief Valve
Heavy-duty direct spring-loaded overpressure protection engineered for thermal boilers, process vessels, oil & gas separators, and superheated steam lines. Fully compliant with ASME Section I & VIII, API 520, and API 526, featuring certified high-discharge coefficient (Kd = 0.975) and bubble-tight shutoff to API 527 up to 95% of set pressure across steam, gas, and hydrocarbon services.
Design, Manufacturing & Testing Specifications
Strict conformance to ASME Boiler and Pressure Vessel Code and API standards ensures reliable relief performance, verified flow discharge coefficients, and field serviceability.
Critical Overpressure Protection Engineering
Engineered for fail-safe instantaneous opening, stable discharge throttling, and chatter-free reseating.
Full-Lift High-Capacity Nozzle
Features an aerodynamically contoured full nozzle profile with certified discharge coefficient (Kd = 0.975). Discharges maximum rated mass flow during transient thermal expansions.
Dual Adjustable Blowdown Rings
Upper guide ring controls the pop action and lift height, while the lower nozzle ring adjusts the blowdown percentage (3% to 7%), preventing valve chatter and pressure overshoot.
Balanced Bellows Immunity
Multi-ply Inconel 625 bellows isolates the disc holder, guiding surfaces, and alloy spring from downstream corrosive flare header gases and variable backpressures.
High-Temperature Open Radiator
For superheated steam above 400°C, open radiator yoke construction dissipates radiant line heat away from the spring, maintaining exact spring modulus and set-point stability.
100% In-House Factory Popping & Leakage Testing
Every safety valve undergoes stringent popping test bench calibration, pneumatic shell testing, and seat leakage bubble counts prior to dispatch.
Tested on high-pressure computerized accumulator benches with 3 consecutive popping cycles demonstrating ±1% set point repeatability.
Air/Nitrogen pressure held at 90% to 95% of set pressure with zero bubbles recorded via underwater displacement device per API 527 standards.
Complete mill test certificates (MTR) covering chemical composition, Charpy V-notch impact toughness, and spring load rate calibration curves.
Frequently Asked Safety Valve Technical Questions
What is the operational difference between ASME Section I and Section VIII safety valves?
ASME Section I applies to fired power boilers and superheated steam generators with strict blowdown mandates (2% to 4% blowdown and 3% overpressure). ASME Section VIII applies to unfired pressure vessels and process plant equipment, allowing 10% overpressure (or 16% for multiple valves) and up to 7% blowdown.
When should a balanced bellows be selected over a conventional spring valve?
A balanced bellows is mandatory whenever superimposed backpressure fluctuates, or when built-up backpressure exceeds 10% of set pressure. The bellows isolates the disc area, ensuring set pressure remains constant regardless of backpressure surges.
How does TSV verify seat tightness per API 527 standards?
In our testing bay, test pressure is raised to 90% (or 95% for set pressures above 50 psig) of the set pressure. The leakage is measured using a 5/16" OD tube submerged 1/2" in water for a minimum of 1 minute to ensure zero or compliant bubble counts.
Safety & Relief Valve Standard & Engineered Models
TSV manufactures an engineered lineup of Safety & Relief Valve configurations for global oil & gas transmission pipelines, refinery manifolds, power plants, and severe industrial processes. Each unit undergoes 100% hydrostatic and pneumatic factory acceptance testing before dispatch.
High-Pressure Full-Lift Enclosed Spring Steam Safety Valve
Enclosed spring bonnet design with upper and lower blowdown adjusting rings, certified for rapid pop action on boiler steam drums and superheaters.
Open Bonnet Radiator Type Thermal Superheated Safety Relief Valve
Open spring architecture prevents heat transfer from high-temperature exhaust steam to the spring alloy, maintaining set point calibration stability.
Low-Lift Resilient Seated Air & Gas Relief Valve
O-ring soft seal disc provides 100% zero bubble leakage at operating pressures up to 95% of set pressure for compressed air and noble gas lines.
Bellows Balanced Backpressure Constant Discharge Safety Valve
Stainless steel bellows isolates the upper bonnet from downstream backpressure fluctuations, preventing set pressure shifts in shared refinery flare headers.
Stainless Steel Chemical Overpressure Safety Relief Valve
Full investment cast ASTM A351 CF8M body with precision Stellite 6 trim for aggressive petrochemical acids and corrosive fertilizer synthesis.
Explore All 4 Safety & Relief Valve Sub-Categories
1:1 aligned with TSV factory catalog. Navigate to spring full-lift steam safety, modulating pilot-operated, parallelled back-flow, or thermal relief valves.
Spring Safety Valve
ASME I & VIII full-lift enclosed spring safety valve with blowdown control rings for boilers and vessels.
Current Series View Page Top ↑Pilot-Operated Safety Valve
Modulating and snap-action pilot valves operating bubble-tight up to 98% of set pressure on gas pipelines.
API 526 Pilot Operated View Details →Parallelled Safety Valve
Specialized parallel dual-chamber safety back-flow valve for liquid discharge, LPG pump bypass, and vessel return.
AHN42F Parallel Back-Flow View Details →Thermal Relief Valve
Compact high-pressure thermal expansion relief valves protecting piping, heat exchangers, and liquid lines.
API 526 / ASME VIII View Details →Request Engineering Submittal & Commercial Quotation
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