From the client’s point of view, construction should be completed as quickly and efficiently as possible.
However, neighbours are less happy about the noise generated from the site. And don’t forget: the issue of noise primarily affects those who work with and around construction machinery.
After all, the ear is our most sensitive sensory organ, and noise protection is also health protection and therefore a key focus for Bauer Maschinen GmbH.
Whether in drilling technology or milling, Bauer has set new standards in terms of noise reduction on special foundation engineering construction sites.
“The reduction of noise is a very central topic in the new and further development of our equipment,” said Christian Heinecker, head of the drilling rigs division at Bauer Maschinen GmbH.
“Thanks to our energy efficiency package, or EEP for short, the Bauer devices have become considerably quieter than their predecessor models without EEP.”
Smart eco mode
Bauer’s smart eco mode, for example, regulates the engine speed depending on the action carried out, which not only reduces the cumulative noise emissions, but also the diesel consumption. This is supported by an automatic engine stop so the machine switches off automatically if it is not used.
Optional additional modules, such as an inflatable soundproofing cladding for the KDK power swivel head or the superstructure, have a further positive effect and can even be retrofitted.
Silent mode is used for Bauer devices with standard technology without EEP.
“This operating mode means that the new Bauer BG 15 H and BG 20 are currently among the most powerful rotary drilling rigs in their class,” Heinecker said.
The silent mode reduces the maximum engine speed and slows down the hydraulic consumers. The result is a sound power level reduction of 2 dBA. Compared to its predecessor, the new BG 20 even has a reduction in cumulative noise emissions of 9 dBA.
With individual measurements, values of only 100 dBA were sometimes found. This is an exceptionally high reduction in noise pollution, because it must be taken into account that the perception of noise is not linear.
In addition to the device, the drilling method also has an influence on noise emissions. A distinction is made here between intermittent drilling and continuous processes. With the latter, the pulling and concreting are carried out in one process. Even when excavating, there are less noise emissions than, for example, Kelly drilling. However, this method is limited in terms of drilling depth and diameter.
When Kelly drilling, the adaptive Kelly drive-in assistant from Bauer reduces the speed during the drive-in process at the transitions of the Kelly bar, which in turn has a positive effect on noise development.
Various assistants are also available for drilling and emptying. The optimal filling level of the drilling tool is displayed to the driver in the B-tronic. When emptying — an activity that used to be carried out manually — one or bi-directional shaking assistants support the driver. In addition, the shock assistant can be used to optimize the intensity of shaking out the auger.
“Whether EEP, silent mode or assistance systems, many individual components ultimately result in a noise-optimized package,” Heinecker said. “We are constantly working to optimize our devices and carry out our own basic research, but are also involved in publicly funded research projects.”
CBC Silent Cutter
The topic of noise reduction is at the top of the list of priorities at Bauer, not only with rotary drilling rigs, but also in milling technology. EEP technology has long been a focus of Bauer’s milling machine carriers, the MC duty cycle crawler excavators. The milling machine itself generates very little noise, as milling is low-vibration. In addition to the engine of the carrier, the main sources of noise is the radiator and hydraulics.
However, with projects in urban environments, for example subway construction, the noise requirements are sometimes very strict.
“If the devices are to run 24 hours in the middle of the city, they have to be correspondingly quiet. This is about health and, last but not least, economic aspects,” said Leonhard Weixler, head of the diaphragm wall technology division at Bauer Maschinen GmbH.
Bauer has developed the CBC Silent Cutter, a compact milling series with low noise emissions, for noise sensitive applications.
The Silent Cutter is available as the CBC 30 for milling depths of up to 80 metres, or the CBC 45 for milling depths of up to 120 metres.
The Silent Cutter is characterized by an innovative concept: the hydraulic unit, which ensures particularly quiet work, is firmly attached to the rear of the carrier, but can be attached to the side or even separately, connected by hydraulic lines, positioned next to the carrier.
“This modular system, which is also available as a low headroom variant, offers maximum flexibility even in extremely tight spaces,” Weixler said.
The unit is housed in a container that is 6 metres long, 2.5 metres wide and 2.5 metres high. Compared to the conventional MC duty cycle crawler crane from Bauer, the Silent Cutter emits 3 dBA, which roughly cuts noise level in half.
“That is a huge step,” Weixler said. “This is possible because with the separate unit, more volume is available for noise insulation.”
The Silent Cutters from Bauer have already proven themselves on many jobsites.
For example, a CBC 45 was used in the narrow street canyons of Singapore for civil engineering work for subway shafts. In 2017, Bauer presented a CBC 30 compact milling machine in a low headroom configuration with a height of only 6 metres at its in-house trade fair. A CBC 30 is currently in production, which will be used in the United States in the future.