Posted to News on 8th Mar 2024, 16:30
Concrete advantages for high-pressure-resistant inductive sensors
High-rise buildings and large construction projects commonly use concrete pumps to deliver the concrete to where it is needed. When a manufacturer of concrete pumping trucks needed reliable, high-pressure-rated inductive sensors, it turned to Contrinex.
The sensors which monitor the position of the piston hydraulic drive cylinder of the pump provide exceptional reliability despite the challenges of pressure cycles and high-pressure peaks. As part of Contrinexs Extra Distance family of inductives, they combine long operating distances, with a pressure-resistant housing to increase longevity and efficiency to reduce the maintenance costs of the pump.
Concrete pumps use a double-piston pump and require two feed cylinders that pump concrete at a working pressure of up to 400 bar (5800 psi). These feed cylinders are driven by pairs of hydraulic cylinders which operate in push-pull opposition. To achieve the 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 because they can cause construction problems and stoppages and risk compromising the building being constructed. 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 start-up, several time-consuming de-aeration cycles must take place before the pump is fully fit for service again. This prolongs the construction stoppage.
The customers 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 1,000-14,500 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 unpressurised side of the housing. This results in an unusually long life under pressure cycle stress.
Two sensors monitor cylinder limit positions in the concrete pump, reporting to the control system. Due to their longevity, which is ten times greater than the market standard, maintenance costs are reduced to a minimum.
