Contrinex’s photoelectric sensors ‘get a grip’ of shipping containers
28 October 2020
At busy container seaports, Contrinex's C23PA photoelectric sensors help ‘get a grip’ of shipping containers on straddle-carriers, the purpose-designed container-handling vehicles which operate around the clock, loading, unloading and stacking containers.
Space utilisation is increasingly important and correctly identifying the size of container picked for each lift is essential for efficiency, so Contrinex photoelectric sensors have been fitted to detect the container size and eliminate the need for drivers to carry out identification checks, saving time and avoiding errors.
• Long sensing range – Up to 500mm
• Small sensor – 30mm x 20mm x 10mm
• Exceptional resistance to extreme vibration during operation.
• Reliable, repeatable sensing performance in demanding operating conditions
• IO-Link– Ideal for Industry 4.0
• Low-cost metal mounting brackets and protective sleeves
• Simple to implement & cost-effective
A fleet of straddle carriers, purpose-designed container-handling vehicles, services a busy container port. As a straddle carrier moves over a container, a central lifting beam lowers and locks onto the corner castings of the container; each lift comprises either a single 40-foot container or two 20-foot containers.
Optimal utilisation of storage space is essential; correctly identifying the size of container picked for each lift is vital. Fitting carriers with sensors that detect the size and type of containers at the time of lifting eliminate the need for drivers to carry out identification checks, saving time and avoiding errors.
The original mechanical sensors proved unreliable, losing calibration when subjected to continuous vibration during normal operation. Although the scheduled maintenance interval for each vehicle is 1,000 hours, mechanical sensors required recalibration at intervals of no more than two or three days. A highly stable replacement sensor system was required.
Highly stable and reliable, the C23PA photoelectric sensors from Contrinex provide a reliable and cost-effective solution. The moulded-resin sensor casings, fitted with coated-plastic sensing faces, are IP67 rated, making them virtually impervious to the harsh, salt-laden environment of a busy container port. Connection to the vehicle’s control systems is via an integral M12 connector and PVC-sheathed cable, allowing easy removal and replacement during routine maintenance.
To confirm the size of the container, two pairs of diffuse sensors with background suppression are mounted centrally on each lifting beam. As the lifting beam descends, one sensor from each pair detects the presence or absence of corner castings at the central lifting points, while the other detects the presence or absence of the gap between two 20-foot containers. The combination of the two eliminates incorrect identification in the unlikely event that the first sensor returns a false-positive signal from a 40-foot container.
A physically small housing and long sensing distances eliminate the risk of accidental damage arising from a mechanical collision, while rugged industry-standard housings and vacuum-encapsulated electronics minimise the effects of vibration.
Operational results have been excellent; the new Contrinex sensors have eliminated calibration errors and reduced maintenance costs significantly.
PLUS Automation aims to help you #MakeSenseofSensors, helping solve applications, improve machine performance and reliability, and reduce costs using Contrinex’s exceptional choice of sensors. Find more information and read other application examples go to www.PLUSAx.co.uk
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