Level switches for sticky products and coating

Separate coverage from residue

A switch should recognize the required presence state and return correctly after the product leaves. Thick film, strings of product, crystals or a deposit bridge can make the empty state resemble immersion. A short tip can reduce product retention but cannot guarantee immunity to every deposit.

Installation can create the problem

A long socket, pocket or poorly draining adapter may retain product around an otherwise suitable sensor. Review the cross-section of the whole connection. The sensor should reach the intended process region rather than monitor liquid trapped in a recess.

Changing thresholds alone can mask a mechanical problem. Before adjusting sensitivity, inspect whether material is genuinely remaining at the sensing position.

Test after aging

Run repeated production and cleaning cycles, then include a realistic idle period. Some products become more troublesome as they cool, dry or cure. Record both false-covered events and failures to detect new product. If cleaning is needed at a defined interval, include that requirement in the maintenance plan and cost comparison.

What to confirm for your application

• Residue thickness and drainage time
• Nozzle and adapter geometry
• Product changes during cooling or drying
• Available threshold adjustment
• Maintenance access and cleaning method