Witt-Gasetechnik, a German gas systems specialist, has built a huge, “unprecedented” testing system for underground explosion prevention in China.

The manufacturing company received an order from China’s Testing Authority for Mining Technologies to supply one of the world’s most powerful gas mixing plants for ignitable gas mixtures.

The testing system - which is now the largest testing tank in the North Pacific rim country with a capacity of 80 m3 - will enable underground mining machines and devices to be tested for explosion safety.

The ‘MG50-6MFC Ex A SO’ includes efficiency enhancements for rapid fill times and additional layers of system protection.

How it works

Prior to gas exposure, the testing tank is emptied extremely quickly and then flooded with an ignitable gas mixture of oxygen (O2), methane (CH2), hydrogen (H2), propane (C3H8), ethylene (C2H4) and acetylene (C2H2), which is then ignited.

To prevent unwanted ignitions and potential accidents, a temperature and pressure wave detection is then deployed to trigger emergency shut-down of the mixer, followed by nitrogen (N2) purging.

The mixing system itself is controlled by a touch screen programmable logic controller (PLC) – ‘Gas Control 50.’ It is designed for simple operation and includes a simulation mode, allowing the user to test run the entire process before the system starts producing a dangerous explosive atmosphere.

Witt china gas explosion testing device

Additionally, an Ex gas analysis module has been integrated to enable monitoring and logging of the gas quality.

Witt has built several other similar systems for similar tasks, like the comparable system delivered to the German Federal Institute for Material Testing (BAM), but nothing of this enormity. Zheng Zhang, Regional Sales Manager for the Chinese Market, explained, “It is about the production of highly ignitable gas mixtures. In terms of technology and safety this was nothing new to us, however due to its size, the plant is something very special.”