Internal vibrator

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Internal vibrator in use when installing a concrete ceiling
Immersion of the internal vibrator and subsequent rise in the air

An internal vibrator (also called a bottle vibrator or immersion vibrator ) is a construction device that is used to compact fresh concrete . Inside the vibrator bottle there is an imbalance that is driven by an electric motor , combustion engine or compressed air supply and generates vibrations . If these vibrations are transferred to the fresh concrete, this leads to a more dense storage of the aggregate in a certain area of ​​action and to an escape of the air enclosed in the concrete. In this way, the concrete reaches the required strength and frost resistance after hardening . In addition, the bond with the reinforcement is significantly improved.

Internal vibrators are usually used in the production of in-situ concrete . The diameter of the vibrator bottle is matched to the mass of the component and the mesh size of the reinforcement and can be between 25 and 150 mm. By creating vibrating lanes (gaps in the reinforcement), even particularly tightly reinforced components can be compacted with the internal vibrator. Alternatively be for compaction vibrators or vibration planks used.

Internal vibrators are listed in the BGL / EUROLISTE under the code number B.9.3 - Internal vibrators . The parameter is the vibrating bottle diameter in millimeters.

application

The internal vibrator is immersed vertically in the fresh concrete, guided to the lowest point and then slowly pulled out again. The distance between the immersion points is chosen so that the areas of action overlap somewhat. As a rule of thumb: 10 times the diameter of the vibrating bottle gives the distance.

In order to obtain a concrete with the required properties that is as free of voids as possible, a few rules must be observed when compacting with the internal vibrator:

  • Basically allowed concrete, which is already frozen , will not be shaken.
  • Compaction should only be started when the fill height is at least 30 cm.
  • If possible, reinforcement and formwork should not be touched with the internal vibrator.
  • Spreading the concrete in the formwork with the internal vibrator leads to segregation and is therefore not permitted
  • The vibration duration at an immersion point must not be too long, otherwise segregation will also occur.
  • Components that are higher than 50 cm (e.g. walls) must be concreted and vibrated in several layers. This is the only way to ensure that the trapped air escapes safely.
  • When the upper layer is compacted, the internal vibrator must penetrate at least 10 to 15 cm into the already compacted layer underneath in order to ensure a good connection between the two layers.

Types

Smaller bottle shaker with associated converter

A distinction is made between the following types:

Internal vibrator with built-in motor
Inside the vibrating bottle there is a stored imbalance that is set in motion by a built-in electric motor. Internal vibrators of this type can achieve a compression rate of between 8 m³ and 52 m³ per hour at a motor speed of 12,000 vibrations per minute, depending on the diameter.
Internal vibrator with external motor
In this design, a flexible shaft drives a pendulum unbalance in the vibrating bottle. The hose-protected shaft is connected to an external combustion or electric motor. With the help of an internal pendulum roller system, the frequency of the vibrating bottle is increased to up to 12,000 vibrations per minute.
Internal vibrator with compressed air supply
By means of a compressed air supply, a ball is set in rotation in a roller conveyor in the housing, thus causing the vibrating bottle to vibrate. The frequency can be continuously adjusted by regulating the air supply. Pneumatic powered internal vibrators are particularly robust.

See also

Web links

Commons : Internal Vibrators  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Main Association of the German Construction Industry: BGL Construction Equipment List 2015 . Bauverlag, 2015, ISBN 978-3-7625-3670-3 .
  2. ^ Gerhard Drees, Siri Krauss: Construction machines and construction methods . Expert Verlag, 2002, ISBN 3-8169-2060-8 , page 23.
  3. ↑ Konrad Zilch, Claus Jürgen Diederichs, Rolf Katzenbach (ed.): Handbook for civil engineers. Springer Verlag, 2002, ISBN 978-3-662-07714-6 , pages 2–290 ff.
  4. ↑ Horst König: Machines in construction: Basics and application . Vieweg + Teubner Verlag, 2008, ISBN 978-3-8351-0250-7 , pages 24-25.