Rotary trowel
The rotary trowel or power trowel is a construction machine that is used to smooth freshly made concrete surfaces . The machine is used when the demands on concrete surfaces in terms of wear resistance and evenness are particularly high. This is the case, for example, in the manufacture of floors in industrial buildings or parking garages.
Rotary trowels are listed in the BGL / EUROLISTE under key number E.6.71 - rotary trowels . The parameter is the disc diameter in millimeters (corresponds to the working width).
purpose
By using a rotary trowel, a pore-free, closed and well-compacted surface with increased wear resistance can be achieved. At the same time, there is a redensification and removal of minor unevenness.
application
The smoothing process may only be started when the hardening of the concrete has progressed so far that only small footprints with a depth of 2 to 3 mm are created when stepping on the concrete surface. The waiting time can be significantly shortened if the fresh concrete is treated flatly with negative pressure and excess water is removed (so-called vacuum concrete ).
The smoothing process is carried out with a friction disc (rough smoothing) or with a wing disc (fine smoothing), depending on the requirements. Usually 5 to 6 transitions are necessary to obtain a finished surface.
Osh
Gasoline-powered engines produce exhaust gas which, in addition to carbon monoxide (CO), contains other hazardous substances , e.g. B. contains hydrocarbons , benzene , carbon dioxide (CO 2 ) and nitrogen oxides (NO x ). Petrol-powered power trowels with and without catalytic converters and gas-powered power trowels are often used next to each other. The CO emissions of the trowel without a catalytic converter also affects people who work with a trowel with a catalytic converter. When using gasoline-powered rotary trowels without a catalytic converter in living spaces and industrial halls, the workplace limit value (AGW) of CO is significantly exceeded. This is also possible when using gasoline-powered trowels without a catalytic converter outdoors.
Gasoline-powered rotary trowels without a catalytic converter must not be used in rooms. Devices with a catalytic converter are permitted in open halls with natural ventilation and with heights over 5 m. However, adequate technical ventilation must be provided. Petrol-powered smoothing machines without a catalytic converter may only be used outdoors if compliance with the AGW is checked and ensured using measurements. This check must be documented.
Types
There are two types of rotary trowels:
- Tiller-guided trowel
- Small areas of up to 400 m² are processed with tiller-guided trowels. The machine has a disc with a diameter between 0.6 meters and 1.0 meters and is driven by an electric or combustion engine.
- Double blade trowel
- The use of double-wing trowels is more economical on large areas of over 400 m², as they are 5 to 6 times more efficient than single-disc trowels. They are driven by an internal combustion engine and have a working width between 2.0 meters and 2.5 meters. They are also equipped with a driver's seat.
See also
- List of construction machinery and construction equipment
- List of construction machinery manufacturers
Web links
Individual evidence
- ↑ Main Association of the German Construction Industry: BGL Construction Equipment List 2015 . Bauverlag, 2015, ISBN 978-3-7625-3670-3 , page E 62.
- ↑ a b c Horst König: Machines in construction: Basics and application . Vieweg + Teubner Verlag, 2008, ISBN 978-3-8351-0250-7 , page 32.
- ↑ a b German Statutory Accident Insurance e. V. (DGUV): Information BG / BGIA recommendations for risk assessment according to the Hazardous Substances Ordinance Carbon monoxide exposures when using power trowels. Retrieved October 21, 2019 .