The Combustible Gas Burning Velocity Tester is developed in accordance with the requirements of UL 9540A and based on ISO 817 Annex C. It records the burning velocity and related auxiliary parameters of combustible gas inside a vertical glass tube through imaging equipment, enabling measurement of combustible gas burning velocity.
1. System Composition
The Combustible Gas Burning Velocity Tester mainly consists of a gas storage tank, combustion tube, ignition system, camera, gas supply system, and exhaust gas treatment system.
Gas Storage Tank
Material: 304 stainless steel
Volume: 16 L
Maximum pressure resistance: 2.5 MPa
Maximum working pressure: 2 MPa
Combustion Tube
Made of borosilicate glass, with wall thickness of 2 mm. Two glass tube diameters are available: inner diameter 40 mm and inner diameter 11 mm. Length: 1.5 m. Glass tube pressure resistance: 1 MPa.
The combustion tube is placed vertically and fixed by machined tooling.
The bottom of the combustion tube is open and equipped with an ignition system and damping orifice.
The top of the combustion tube is connected to a mixing vessel. The test gas enters from the top and exits from the bottom. Before ignition and before flame propagation ends, the top shall remain closed.
Quenching meshes are installed at both ends of the tube, with mesh size of 1 mm.
Pressure relief valve value: 150 kPa.
Normally closed explosion-proof dual solenoid valves are used for redundant protection.
A stainless-steel flame arrester is installed at the pipeline inlet, providing double protection together with the quenching mesh to prevent flashback.
Camera
A high-speed industrial camera system is used to record the flame burning and propagation process.
Equipped with an adjustable-height camera mounting bracket.
A reflector is installed on the side of the combustion tube, allowing the camera to capture both front and side flame images simultaneously.
Industrial flame image analysis software is used to calculate flame height.
Ignition System
The ignition system is installed at the bottom of the combustion tube.
The ignition electrodes are made of tungsten with a diameter of 1 mm. They are inserted from both sides at the bottom, with a spacing of 6.4 mm.
Ignition transformer output: 15 kV, 30 mA.
Ignition time is editable, with default setting of 0.3 ± 0.05 s.
Ignition current and ignition time can be monitored.
Gas Supply System
The gas supply system consists of a suction pump and flowmeter.
Imported KNF suction pump, flow rate: 33 L/min.
The sample gas flow is stably supplied through the flowmeter.
Equipped with a mixing vessel and magnetic stirrer to ensure uniform mixing of the test sample gas.
Before testing, air purging is performed to remove impurities inside the combustion tube.
Before testing, sample gas purging is performed to ensure accurate sample gas concentration inside the combustion tube.
Exhaust System
Control valve connected to air compressor.
Exhaust pipe inner diameter: 12 mm.
Exhaust pipe material: stainless steel and PTFE tubing.
Used to discharge combustion products from the pipeline during the test process and conditions, and to remove mixed gas from the tank and pipelines.
Gas Mixing System
Gas mixing accuracy: 0.5%.
Magnetic stirring: built-in magnetic stirrer to ensure uniform sample gas mixing.
Stirrer speed is adjustable, with default speed of 300 rpm.
Exhaust Gas Treatment System
The tail end of the combustion tube is connected to an expansion vessel and gas washing bottle.
The gas washing bottle is filled with absorption solution to absorb harmful components in the exhaust gas.
Temperature Acquisition
Imported Omega Type K sheathed thermocouple × 1, for the gas mixing tank.
Imported Omega Type K surface-mount thermocouple × 2, for the test tube.
Imported Omega Type K sheathed thermocouple × 1, for the top inside the glass tube.
The temperature difference between both ends of the combustion tube is monitored and shall be less than 1°C.
Pressure Acquisition
Vacuum pressure sensor: range 0–35 kPa, accuracy 0.25%, response time 2 ms, working temperature -40°C to 85°C.
Gas mixing pressure sensor: range 0–1 MPa, accuracy 0.25%, response time 2 ms, working temperature -40°C to 85°C.
Data Acquisition
Time and temperature: time error ±0.1%, temperature error ±0.5°C.
Gas mixture concentration, gas mixing pressure data, etc.
Ignition current.
Burning velocity calculation.
Gas Leakage Alarm
Can detect H₂ and alkane combustible gases.
Equipped with audible and visual gas leakage alarm function.
Interlocked linkage system shuts valves and terminates the test.
Dual alarms are arranged at the top and bottom inside the gas tank cabinet to monitor leakage of gases with different densities.
Test Software
Computer-based virtual instrument test platform edited with LabVIEW, using modular design.
Manual and automatic control modes are available.
In automatic mode, purging, gas mixing, stirring, sample delivery, ignition testing, video recording, and exhaust discharge can be fully completed according to programmed settings.
Parameters can be set, including vacuum threshold, vacuum cycle count, ignition time, target gas mixing concentration, magnetic stirring time, upper safety pressure limit, pipeline flushing time, etc.
2. Equipment Dimensions
Dimensional tolerance:
Relevant dimensional requirements in the proposal shall meet the following accuracy requirements.
|
Linear Dimensions |
≤1 mm |
±0.05mm |
|
>1mm≤25mm |
±0.1mm |
|
|
>25mm |
±0.5% |
3. Key Parts List
| No. | Part Name | Brand | Specification |
|---|---|---|---|
| 1 | Vacuum pressure sensor | Kewill, Germany | Pressure range: 0–35 kPa; test accuracy: 0.25%; response time: 2 ms |
| 2 | Gas mixing pressure sensor | Kewill, Germany | Pressure range: 0–1000 kPa; test accuracy: 0.25%; response time: 2 ms |
| 3 | Solenoid valve | Roke, Germany | Brass valve body; high-pressure resistant, normally closed, with signal feedback |
| 4 | Pressure relief valve | Roke, Germany | Pressure relief value: 0.9 MPa |
| 5 | Switching power supply | Mean Well | 24 V, 75 W |
| 6 | Ignition transformer | COFI, Italy | 15 kV, 30 mA |
| 7 | Acquisition module | Advantech, Taiwan | 16-bit, 8-channel, accuracy 0.5%, RS485 |
