Offline Safety Valve Calibration Bench

Scope of Application:

This equipment is applicable to the testing of performance indicators such as set pressure, reseating pressure and tightness of all types of full-lift and low-lift safety valves.

Reference Standards:

TSG 92-2026 Safety Technical Specification for Safety Accessories of Pressure-bearing Special Equipment

TSG ZF001-2006 Supervision Regulation on Safety Technology for Safety Valve

GB/T 12241-2021 General Requirements for Safety Valves

GB/T 12242-2021 Pressure Relief Devices — Performance Test Methods

GB/T 12243-2021 Spring-loaded Directly-Loaded Safety Valves

GB/T 32291-2015 Off-line Calibration and Evaluation of High and Ultra-high Pressure Safety Valves

Main Technical Parameters:

(1) Maximum applicable nominal diameter: DN400 mm. Larger bore sizes are available upon custom request.

(2) Maximum test pressure: 160 MPa. Higher pressure versions can be customized on request.

(3) Pressure measurement accuracy: Equipped with Class 0.4 pressure gauge; higher accuracy grades are optional as required.

(4) Test media: Nitrogen, compressed air or clean water. Gas-liquid dual-purpose units are available for customization.

Main Functions and Features:

(1) The pressure calibration of the safety valve under test is performed manually. Test pressures are read and recorded visually via a high-precision Class 0.4 pressure gauge.

(2) Test procedure: The built-in pneumatic gas booster system of the control console delivers high-pressure gas to the gas storage vessel (high-pressure accumulator). High-pressure gas from the vessel is fed into the safety valve under test. Operators manually toggle the calibration switch to connect or cut off pressure in the test line. The safety valve is deemed qualified if it opens at the set calibration pressure; otherwise, it is unqualified.

(3) The clamping seats of the calibration bench adopt hydraulic clamping with electro-hydraulic clamping technology. The output pressure is adjustable, and pressure holding is easy to operate for fast clamping of test valves.

(4) Each clamping seat is of three-jaw design with evenly distributed jaws for stable clamping force. The jaws feature a new bidirectional high-low foot structure, suitable for clamping valves of various shapes and dimensions.

(5) The calibration bench is equipped with two clamping seats: one for DN15 ~ DN200 and the other for DN200 ~ DN400 tests.

calibration bench

1.Pressure Gauges: All calibration pressure gauges are high-precision Class 0.4 gauges. There are 3 (4) measuring ranges, with 2 gauges for each range, totaling 6 (8) high-precision pressure gauges. Pressure gauges of each range are individually controlled by a control valve.

high-precision pressure gauge

2. Gas booster pumps adopted in the built-in gas boosting system of the control console are independently designed, machined and manufactured by our company. All internal seals are originally imported, ensuring stable system pressure during clamping and continuous high-pressure gas output during testing.
3. Gas Test: Compressed air of 0.3–0.8 MPa is used as the drive power for the HA60 gas booster pump. Nitrogen from nitrogen cylinders serves as the test pressure source. Cylinder nitrogen is pressurized by the gas booster pump and then fed into the gas storage vessel for calibration.
4. In compliance with the new regulation TSG 92-2026, test vessels are installed inside the equipment: one 2 L high-pressure vessel with a pressure rating of 40 MPa for safety valves with a nominal diameter ≤ 65 mm; one 12 L high-pressure vessel with a pressure rating of 40 MPa for safety valves with a nominal diameter > 65 mm and ≤ 150 mm; an additional 6 L high-pressure vessel rated at 40 MPa is also fitted. When the three test vessels (2 L, 12 L and 6 L) are opened together, the total volume reaches 20 L, for calibration of safety valves with a nominal diameter > 150 mm.

5. In compliance with the new regulation TSG 92-2026, the inner diameter of the test piping and valves between the test vessels and the clamping port shall be ≥ 8 mm.
6. In compliance with the new regulation TSG 92-2026, the pressure tap of the precision pressure gauge measuring system is modified and connected between the high-pressure test outlet inside the clamping bench and the test vessels.
7. In compliance with the new regulation TSG 92-2026, the equipment is equipped with an automatic bubble counting leak detector. It automatically counts bubbles and records the data into the calibration record during the tightness test after three calibration cycles.

automatic bubble counting leak detector

8. All valves, pipe fittings and connectors are made of stainless steel.
9. Multiple test toolings including center gaskets and British reducing male adapters are supplied. Customization is available upon request to meet the test requirements for various series of safety valves.

Test Fixtures

FD1 Equipment Configuration：

FD2Equipment Configuration：