Suction excavators are ideal where narrow construction sites and high efficiency requirements coincide. Heinrich Kern Straßen‑ und Tiefbau GmbH has already tested this in the field – and now has its own combination suction excavator in its fleet.

The turbine roars to life inside the huge machine. The Rivard suction excavator on an Arocs 3251 8x4/4 NLA BigSpace begins its work. “The turbine draws well over 30,000 cubic metres of air per hour. That’s the volume of ten Olympic‑size swimming pools. The resulting suction slurps up practically any material – sand, mud, water, gravel, soil, and stones up to over 100 kilograms”, explains Dennis Depau. “It would swallow entire kerbstones. And, if necessary, over a distance of more than 100 metres.”

Dennis Depau is a driver at Heinrich Kern Straßen‑ und Tiefbau GmbH in Dieburg. However: Driving is almost his side job. Most of the time, he operates the EXVAC SE.10, the top‑of‑the‑range model from French manufacturer Rivard. His task today: The pipes and connections have to be exposed for a new construction. While mini‑excavators and shovels and muscle power would be at work for hours, the Arocs rolls the suction excavator up to expose a clean hole in a minimally invasive manner and in the shortest possible time.

Onlookers gather quickly to watch this unusual procedure. Company boss Heiner Kern is brought here by a very tangible interest. The 55‑year‑old is the fourth generation to manage Heinrich Kern Straßen‑ und Tiefbau GmbH in Dieburg. The Arocs and its extraordinary design has only recently been added to the company’s fleet: an investment for the future. No wonder then that Kern occasionally wants to see its capability for himself.

Meanwhile, the suction excavator is working its way through the soil. The green suction arm – folded up at the rear of the vehicle to save space while driving – is extended with a rigid suction pipe. The toothed rim at the end rotates, loosening the soil, then the instrument disappears inside the machine in the blink of an eye. The 375 kW OM 471 of the Arocs delivers the necessary power via the PTO.

Within half an hour, all the pipes next to the building shell are freely accessible. “We gain at least one and a half work days per week with this machine”, Kern estimates. In addition, it reduces the workload for his people. Kern is active in the guild and knows all too well about the issues with young people working in civil engineering. “If you’re looking for good people, you have to make the job more attractive”, he says.

It worked for Dennis Depau: Kern was able to bring this experienced man into the company thanks to the Arocs suction excavator. “We are all Mercedes fans here”, says Depau. “Not everyone can enjoy their lunch in such a luxurious cab.”

The Arocs has a lot more to offer, however. “For example, on construcktion sites we can remote control the vehicle from outside the cab”, explains Kern. For safety reasons, the Arocs is equipped with cameras and sensors and has several emergency stop buttons on the outside. “The fourth axle also steers. This means that even narrow construction sites are no problem for this manoeuvrable vehicle.”

The enormous power of the suction excavator can be used in a targeted manner: “This allows us to expose pipes all around without even touching them”, says Kern. “Where the soil is too dense, a second man helps out with the compressed air lance. This minimalistic excavation also offers added safety: Anyone who has ever had to jump out of the pit because an excavator bucket hit the gas or power line knows why.” What’s more, everything is done cleanly. Six high‑performance filters keep the exhaust air dust‑free. The material remains in the 10.5 cubic metre trough inside the machine. This trough can be tilted sideways – also via remote control.

“I have been following the development of suction excavators with interest for a long time”, says Kern. “But a machine like this wants to be busy. In terms of value, it’s basically a single‑family house on wheels.” All the same: Before purchasing, he had the opportunity to test the Rivard EXVAC extensively using a demo machine from CyclonTec GmbH. “We are closing a gap with our offer”, report Iris Girmann and Sebastian Rösner, who have been jointly responsible for suction excavator rentals and sales for three years. “Instead of buying the service or waiting out long delivery times for their own vehicle, our customers can use the rental option to get an idea of real conditions before investing or to bridge the wait time in a productive manner.”

Kern tried it out – and is still completely convinced by the results to this day. “The only mistake was not getting the suction excavator sooner.”