Card Autoleveling Equipment
category
Card autoleveling maintains constant sliver weight despite variations in material feed. Systems are classified as short-term (10–12 cm lengths, rarely used), medium-term (>3 m lengths), or long-term (>20 m, count maintenance). Regulation is typically performed at the feed by adjusting feed roller speed, using open-loop (upstream sensing) or closed-loop (downstream sensing) control. Long-term autoleveling is an integral part of all modern cards.
Role
Autoleveling is essential because tuft feed systems react sensitively to variations, unlike the inherently even lap feed they replaced. The card produces the first cohesive intermediate product, and sliver irregularities propagate through to the yarn.
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Subtopics
- Long-Term Leveling (Count Maintenance) The most common principle measures sliver count at the delivery (using active pneumatic or mechanica…
- Medium-Term Leveling (Optical and Feed-Based) Former Zellweger equipment used an optical measuring device built into the protective cover above th…
- Short-Term Leveling at Card Delivery Short-term autoleveling uses a drafting arrangement before coiling, with an upstream measuring funne…
- Active Pneumatic Measuring System A convergent funnel before calender rollers generates air pressure exceeding atmospheric as fibre ma…
- Mechanical Measuring System (Disc Rollers) Two material-forwarding rollers, one movable relative to the other, measure sliver volume through th…
- Rieter Integrated Card Leveling System The Rieter system combines infeed count sensing (input signal 1), feed speed control in the chute (o…
- Card-Integrated Drafting Modules Modern cards can be equipped with integrated drafting modules: Rieter offers SB (unleveled, max draf…
- Open-Loop vs Closed-Loop Control Principles Open-loop control places the measuring point upstream from the regulation point, enabling fast respo…
- Optical Fibre Layer Measurement on Cylinder An optical measuring device detects relative variations in the cross-section of the fibre layer on t…
- Compound Card and Process Integration The compound card joins the card to the first passage draw frame, placed directly following sliver d…