?(By Wang Jiahui) With light “boom–”, a red cleanness vehicle slowly cleans the road ground, leaving a clean and nearly new asphalt pavement. The suction excavator, which have done cleanup in the aftermath of Tianjin explosion, was tested for the first time in terms of its dry-cleaning performance in the Comprehensive Disposition Plant in Dongcun in Beijing.

Equipped with detector for toxic or harmful substances

“The scene, covered by varied heavy dust and dirt, was such complex that some parts of it remain 3-4cm’dirt”Said Mr. Huang Xiangyang, the General Manager of Hishan Machinery Co., Ltd, who is the leader in the team for development of the suction excavators of which one has been sent to Tianjin for the cleaning work in the aftermath of the bomb.

For 15 days, the suction excavator worked nearly 10 hours every day. With a 9 cubic meters’tank, the excavator had to transport 4 to 5 times of pollutant.“As part of the area was parking lot, there remained car parts and melts of components. It is quite difficult to clear, and concrete and metal fragments would stab tires at nearly 4cm.” Mr.Huang told us.

The chemicals enhanced the difficulty of cleaning. “An ordinary cleaning vehicle causes flying dust when working; and the hazardous materials percolate through the soil after watering” Mr. Huang said. The suction excavator with powerful negative pressure avoids those disadvantages. The detector for flammable and explosive materials and remote controller are installed, thus guaranteeing safety of the operator.

Three-Level Filtering

After the clearance by suction excavator, the asphalt pavement was so tidy that pebbles on the surface of the road can be seen clearly. Even the dust of 4cm depth in the small gap can by sucked. Mr. Huang told us that the suction excavator can be used to dry-cleaning of road. The suction inlet is installed with six high pressure pumps working simultaneously. The dust on the surface of the ground and in the gaps would be lashed into the air. Then he powerful negative pressure would suck the dirt into the tank at a very fast speed.

It is said that the air flow speed at the suction hose mouth can reach the traveling speed of the sound. The negative pressure produced can be up to 90 kilograms and forcefully peeling pollutant off. Things like dirt, mud, oil contamination and even gum can be sucked and cleared, avoiding second-spreading of pollutant. “The ground cleaned by ordinary cleaning cars seems to be clean enough, but something invisible to eyes remains.”Mr. Huang said. The suction excavator does three-stage work of dust filtering, achieving industrial cleaning standard. It can also be used to non-destructive excavation, and reduce the damage to underground utilities like wires, pipes.