The reliability of a temperature and pressure relief valve (T&P valve) comes down to two actions: opening decisively when danger appears, and closing tightly once it has passed. Is the set pressure accurate? Does it reseat promptly? Does the thermal element actuate exactly at its calibrated temperature? These dynamic characteristics cannot be judged by eye — they must be assessed by an automated, high-precision, traceable inspection system.
Ouxun Intelligent Technology (Taizhou) Co., Ltd. is a technology company dedicated to developing and manufacturing test equipment for temperature and pressure safety valves. We supply valve producers worldwide with complete solutions from single-station benches to fully automatic inspection lines, with particular depth in two-dimensional pressure and temperature lift-and-reseat testing, so that no deviation in any actuation parameter goes unnoticed.
What We Deliver Is Not Just a Machine — It Is a Complete Actuation Test System
For Ouxun, the core of safety valve testing is precise capture of the dynamic process. Around the actuation characteristics of T&P valves we have developed a modular, combinable range of test equipment:
1. Combined Set-Pressure / Actuation-Temperature Bench — Accurate Two-Dimensional Open/Close Measurement
This is the core station for safety valve verification. One machine integrates a high-precision pressure sensor (class 0.05) with a fast-response temperature sensing system, and programmes the full pressure/temperature rise and fall sequence, recording and judging automatically:
(a) Pressure actuation: set pressure and reseat pressure
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Set pressure test: pressure rises slowly at a controlled rate; the system samples at high frequency to capture the pressure peak at the instant the disc lifts, and judges automatically whether it falls within the tolerance band (for example ±3%). Any point outside the limit triggers an alarm and flags the data.
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Reseat pressure test: after lifting, the valve switches to a pressure decay programme while the system monitors continuously until the disc returns to its seat and sealing is restored. Reseat pressure is calculated automatically and checked against the required lower limit (for example no less than 80% of set pressure), eliminating the risk of delayed or failed reseating.
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Blowdown analysis: the difference between set pressure and reseat pressure is calculated automatically and a pressure-time actuation curve is output, giving intuitive data for dynamic performance optimisation.
(b) Temperature actuation: opening and reseat temperature
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Opening temperature test: in a precision-controlled oil bath or hot-air chamber, temperature rises slowly with control accuracy of ≤0.5 °C. At the instant the thermal element actuates, the system latches the opening temperature. Whether 93 °C, 99 °C or a customer-specified point, it is captured precisely.
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Reseat temperature test: immediately after actuation a controlled cooling programme starts and monitoring continues until the disc closes again, recording the reseat temperature. This verifies that the thermal bulb resets reliably and that the valve shuts off promptly as temperature falls, avoiding continuous leakage.
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Automatic hysteresis calculation: the report outputs opening temperature, reseat temperature and the hysteresis value, fully satisfying the stringent requirements of EN 1490, ASME and other standards for thermal element actuation.
2. High-Sensitivity Tightness Test Equipment
Leak testing verifies seat tightness in the closed position, including after reseating. We offer differential-pressure air-tightness benches and underwater vision inspection stations, with detection capability down to 0.1 Pa differential resolution or micron-scale bubbles. Test pressure and dwell time are programmable, and results are bound automatically to the product barcode.
3. Durability / Life Cycling System
This reproduces the repeated lift-and-reseat cycles a safety valve sees during its service life. The system runs the set number of cycles automatically, monitoring drift in set pressure, reseat pressure, opening temperature and reseat temperature at every actuation. Any parameter degradation or abnormal reseating triggers an immediate alarm and stop, with a trend report that supports service life prediction.
4. Body Strength Test Bench
High-pressure hydrostatic testing of the valve body to verify structural strength, with automatic pressure holding and make-up, real-time pressure curve display, and automatic judgement of leakage and deformation.
5. Environmental Test Equipment
High/low-temperature cycling chambers, salt spray corrosion testers and similar equipment verify the actuation stability of thermal elements and seals under different environments.
Intelligent Data System: Every Open and Close on Record
Every machine we deliver comes standard with Oxi-DAS, our own intelligent inspection data acquisition and analysis system:
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One-code traceability: each valve body carries a unique code; set pressure, reseat pressure, opening temperature, reseat temperature and all other parameters are archived automatically, creating an electronic birth record.
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Automatic judgement, no human intervention: the system outputs Pass/Fail against preset criteria, removing favouritism and operator error.
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SPC statistical process control: Cpk of set pressure, pass rate of reseat temperature and other metrics are calculated in real time, with quality drift warnings sent straight to management.
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Actuation curve playback: the historical curve of any valve can be retrieved to review the lift-and-reseat process in detail.
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Automatic reporting: factory inspection reports export in one click, with customisable templates.
Modular Design to Match Your Line
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Single-station bench: manual loading, suited to start-ups and small-batch laboratory validation — a cost-effective entry point.
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Multi-station cell: interfaces with the production line for a tight test cycle in high-volume manufacturing.
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Fully automatic line: robotic loading and unmanned operation, completing lift/reseat testing and tightness testing in one pass.
Why Choose Ouxun Intelligent Technology
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Focus: deep experience in valve inspection, particularly two-dimensional pressure and temperature actuation testing of T&P valves.
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Precision: core sensing components from leading international brands, assembled and commissioned at our Taizhou facility to guarantee lift and reseat capture accuracy.
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Intelligence: our own data system delivers paperless recording, automatic judgement and full life-cycle traceability of lift/reseat parameters.
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Service: end-to-end support from equipment selection and commissioning to operator training and maintenance.
Real safety means every lift happens exactly when it should, and every reseat closes completely. Ouxun Intelligent Technology (Taizhou) Co., Ltd. provides T&P valve manufacturers worldwide with quality assurance that stands up to the data.