Concrete is composed of cement and ‘other ingredients’ such as limestone, gravel, granite, fly ash, etc. Some soft-grind components such as sand and parts of water will give you a perfect concrete structure.
Concrete is a very heavy fluid (normal concrete = 2400 kg/m3). Concrete is viscous and very abrasive because of the sand and the cement elements.
After mixing the components with the water a chemical reaction occurs: “hydration”. In this way the elements bond together, creating a stone like construction material, concrete.
Concrete is probably the most common used construction material in the world. The modern versions of concrete are reinforced concrete and pre-stressed concrete.
Pumping concrete mixture using a peristaltic pump
A Research Institute for Building Materials in the Czech Republic wanted to develop a concrete blend for different kinds of concrete applications and concrete products such as sound screens round the freeway, bottom cover of the street lighting, underground for cable channel etc. This type of concrete blend is very economical. Firstly, the concrete does not need any surface finish or paint and secondly, concrete is cheaper than common metal and is also lighter than common metal or cast iron.
The fibreglass concrete properties can be very solid and massive (approx. 10mm long). The wall thickness of the fibreglass concrete in end products can be therefore very thin: starting with a wall thickness of only 3mm (or up). Even then this kind of concrete has sufficient strength. This concrete mixture with fibreglass is a so called reinforced concrete.
Why use a peristaltic pump?
Pumping concrete is not done easily. Because the mixture is viscous, abrasive and contains also sand and fibreglass most pumping principles are not able to pump this mixture.Problems that occur, when using other pumping principles are:
- High viscosity problems (pumping with a centrifugal, screw pump or air operated diaphragm pump)
- Abrasive problems (in fact concrete mixture is too abrasive for all pumping principles)
- Non-Fluidizing problems (a gear pump would cause many floating problems)
In this pumping process the Verderflex peristaltic hose pump doses the concrete mixture into mouldings to create the concrete for an end product, such as sound screens, bottom covers of the street lighting or underground cable channels.
Process specifications:
- Fluid is concrete mixture with fibreglass
- Specific gravity up to 2,3 kg/l
- Pressure is approx. 10 bar (depending on length and size of the discharge filing hose)
- Capacity is approx. from 1,5 up to 3 m3/h
- Pump type is Verderflex VF40 with motor 3 kW, gear box 36 RPM at 50 Hz and FC
According to Paul Dale, Verderflex marketing manager: "The Verderflex peristaltic pump is a very economical and efficient solution to pump concrete. The life time of the Verderflex hose is excellent, viscosity is not a problem, the hose is competent to withstand all abrasive matters."
