Patent CN215543717U - Dust & Iron Removal Unit for Calenders

In electrode sheet production the calender (roller press) is where coating is densified onto the foil. The process must stay clean to keep the web defect-free - yet the specification of CN215543717U records a familiar production-floor problem: the roller presses then in use were very inconvenient to clean, and the machine had to be stopped for cleaning, which heavily cut production efficiency. Metal chips and coating dust also settle where they can be pressed back into the electrode.

CN215543717U, filed on 26 August 2021 and granted on 18 January 2022, answers with a self-cleaning unit built around the calender rolls: electromagnets pull ferrous chips out of the web zone, air pumps draw dust off the roll faces, and screw-driven brush plates sweep the captured debris into a collection drawer - all while the rolls keep turning.

Patent Information

The Production Problem This Patent Solves

Cleaning a calender used to mean stopping it. In the lithium battery electrode sheet process - mixing, coating, rolling, slitting, tab welding and more - rolling makes the active material bond to the foil densely and uniformly. But as rolls turn, dust and metal fragments accumulate on their faces, and the presses in use at the time had no way to be cleaned without halting the machine. The specification identifies that stoppage as a direct hit on production efficiency.

Iron is a different problem from dust. Ferrous particles near a calender are not just cosmetic dirt. If a metal chip is picked up by the web and pressed into the finished electrode it becomes a potential internal short circuit in the assembled cell. Suction alone cannot reliably lift magnetic chips off a moving roll - that is why the unit combines air suction with electromagnets.

Consistent rolling thickness also needs a stable process. The specification notes that different electrode tensions change the plasticity of the electrode material and directly influence the rolled thickness, so the machine that handles the web must not disturb tension while it cleans.

How the Mechanism Works

Frame and roll carriage (claim 1)

The unit is built on a bottom plate structure and two side plate structures that carry the upper and lower calender rolls. Each roll runs on a roll shaft mounted in the side plates, driven by motors on a motor frame that holds four motors. A control panel on the side structure is electrically connected to the four motors, the air pumps, both brush-plate motors, the electromagnets and the external power supply, so an operator starts and stops the whole cleaning cycle from one place.

Magnetic capture and vacuum pick-up (claim 1)

Beside each roll sits a debris attraction box whose cavity facing the roll is arc-shaped, so the whole box forms a C shape that hugs the roll. An electromagnet at the outer end of each box is energised during operation and attracts ferrous (iron) chips out of the roll zone. On the opposite side of each roll, suction ports connected by tubes to two air pumps draw dust and fine debris off the roll faces.

Screw-driven sweeping inside the debris boxes (claims 2 and 4)

Inside each debris attraction box, a square brush plate lined with fine bristles is threaded on a first lead screw mounted in the side plate structure. When the screw turns, the plate sweeps the chips that the electromagnet has pulled out of the web zone towards the collection end of the box.

Base-plate sweeping and collection drawer (claims 2 and 8)

A long brush plate motor in the middle of the bottom plate structure turns a second lead screw, and a long brush plate threaded on that screw carries bristles on its lower edge and both sides. It sweeps chips and dust that fall onto the bottom plate out of the machine. At the end of each debris box a debris collection box receives the swept debris; a drawer at its lower end, fitted with a handle, is pulled out for emptying.

Mobility and anchoring (claims 5 to 7)

The bottom plate stands on four threaded levelling posts tipped with suction cups, so the unit is fixed firmly in front of the calender; a universal caster (roller wheel on a rotating disc) lets it be moved to the next machine when needed. A reinforcing plate between the two side plates stiffens the frame.

Working cycle

With the unit switched on through the control panel, the motors drive the upper and lower rolls, the electromagnets pull metal debris into the attraction boxes, and the air pumps draw dust from the roll faces. Periodically the control panel runs the two lead-screw motors: the square brush plates push the captured debris inside the boxes into the debris collection boxes, and the long brush plate sweeps the bottom plate clean.

Claimed Benefits

How It Compares with Stopping the Calender to Clean It

Cleaning a calender used to mean stopping it. As the rolls turn, dust and metal fragments accumulate on the roll faces, and the presses in use had no way to remove them in production. This unit cleans while the calender keeps running.

Where This Technology Is Used Today

This patent protects the self-cleaning architecture of TOB's calender support equipment. The principle it covers - electromagnet capture plus vacuum pick-up plus screw-driven sweeping, running without a line stop - is how our cleaning units keep electrode calendering stations free of iron chips and dust.

• Automatic electrode dust cleaning and brushing machines
• Electrode roller press / calendering equipment

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Full specification and drawings: CN215543717U on Google Patents

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