A manufacturer of concrete pumps relies on Contrinex High Pressure sensors (Extra Distance family) to monitor piston position in the hydraulic drive cylinder. The excellent resistance of these sensors to pressure cycles and high pressure peaks, and their exceptional longevity, increase efficiency and reduce maintenance costs for these concrete pumps.
Concrete pumps work with a double-piston pump. This requires two feed cylinders that pump concrete at a working pressure of up to 400 bar (5800 psi). These feed cylinders are driven by hydraulic cylinders. The cylinder pairs operate in push-pull opposition. To achieve maximum possible efficiency, the timing of this push-pull operation must be precisely coordinated. It is therefore essential to monitor the cylinder limit position with sensors that are resistant to high pressure.
The dynamic stresses on all components built into the hydraulic system are very high, due to constantly changing pressure cycles during pump operation.
Concrete pump failures are extremely costly and lead to construction stoppages. If the breakdown is due to problems in the hydraulic system, all the hydraulic oil must be drained to correct the fault. Then, after refilling and before startup, several time-consuming de-aeration cycles must take place before the pump is fully fit for service again. This prolongs the construction stoppage.
The customer’s requirements for longevity and resistance to high peak pressures are essential to guarantee the smooth operation of such systems.
Contrinex High Pressure sensors (series 500P) withstand the necessary pressure levels (peak pressure up to 1000 bar - 14500 psi) due to a patented process whereby a solid ceramic disk is built into the stainless steel housing.
These sensors are fully resistant to dynamic stresses. A patented technology ensures that all electronics, including the ferrite core and coil, are located on the unpressurized side of the housing. This results in an unusually long life under pressure cycle stresses.
To monitor cylinder limit positions in the concrete pump, two sensors are installed and connected to the control system. Due to their longevity, which is ten times greater than the market standard, maintenance costs are reduced to a minimum.