Photoelectric cap-presence sensor for bottle conveyors
Bottle conveyors · cap present / cap absent
A cap-presence sensor checks whether a closure occupies the detection point as a bottle passes. Its output needs a bottle reference so the control system can distinguish a missing cap from an empty gap on the conveyor.
Photoelectric presence sensors aimed at bottle closures on a conveyor, paired with bottle detection to identify a missing cap. Photoelectric sensor (9418) covers the broader optical sensing families; High-speed rotary bottle capping machine (576) covers applying the closure, and Capping spindle (4927) covers the mechanical head. Foil-liner detectors, torque testing and full vision closure inspection are different products.
CNFX editorial research · Sources checked October 16, 2026 · 3 sources
Banner’s food-and-beverage application brochure describes a Q12 fixed-field sensor for cap inspection in confined spaces, using the fixed-field method to disregard cap colour changes. The example identifies a sensing approach for closure presence; evaluate the chosen sensor against the actual cap and bottle variants at the mounting position. [2]
SICK’s missing-cap example uses a WTB4SC photoelectric proximity sensor for the cap and a WLG4SC retroreflective sensor for the bottle. The distinct sensors provide distinct reference signals rather than asking the cap sensor to infer whether a bottle is present. [1]
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An empty conveyor gap must not become a missing-cap reject
SICK’s Smart Sensor example combines the cap and bottle sensors through a Y-adapter and configures the logic in SOPAS. Its published output states are: [1]
Commission those states with known capped and uncapped bottles and with an empty conveyor gap. Record the sensor positions, signal meanings and downstream reject interface for the inspected bottle format. The example is a logical missing-cap signal, not a specified electrical output type or a universal conveyor timing value. [1]
Missing foil and cocked caps need their own detection function
Pillar’s bottle-and-cap detection package assigns an inductive sensor to missing foil, a laser beam to loose or cocked caps, and a photoelectric eye with a conveyor encoder to stalled-bottle faults. These checks address different conditions from a photoelectric cap-presence signal. [3]
Pillar also lists reject delay and duration control for its missing-foil/loose-cap package. Define which defect is to cause a reject and how that decision follows the bottle through the line. The same page limits its detection packages to portable systems, so confirm equipment compatibility rather than applying that package to every sealer. [3]
Supply capped and uncapped samples for each bottle format, cap material and colour, bottle-position variation, mounting space, conveyor speed and spacing, washdown conditions, required signal interface and reject arrangement. Ask the supplier to demonstrate the required defect cases at the installed sensing position.
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Specify the closure samples and the reject decision
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 16 October 2026
Buyer questions
Why use a bottle sensor as well as a cap sensor?
SICK’s example asserts its missing-cap output when a bottle is detected without a cap, but leaves the output unasserted for an empty conveyor gap. [1]
Does detecting a cap also detect the foil liner?
Pillar assigns missing-foil detection to an inductive sensor and cocked-cap detection to a laser beam, as separate functions in its package. [3]
What approach does Banner describe for changing cap colours?
Its application brochure describes Q12 fixed-field sensing for closure inspection while disregarding cap colour changes. Confirm operation on the actual sample range and mounting geometry. [2]
Sources and what still needs a direct check
Sources checked 2026-10-16. SICK supplies the paired-sensor missing-cap logic. Banner documents a fixed-field cap application; Pillar separates foil, cap-position and bottle-motion checks in its own sealer package.
