Industry Application Background and Equipment Matching

One of the core processes for menthol cigarettes is to precisely coat menthol solution on the inner side of cigarette paper adjacent to tobacco shreds, so as to realize quantitative and accurate addition of menthol ingredients.

Extremely high precision is required for the coating position. Offsetting outward will cause material waste, while excessive coating will impair combustion performance.

Precision metering pumps serve as the core component. They must deliver tiny volumes of menthol liquid continuously and in real time according to the speed of cigarette makers (typically 8,000 to 16,000 cigarettes per minute) to guarantee consistent coating dosage for every cigarette.

Core challenge: When the cigarette maker accelerates or decelerates, the pump output needs to respond and adjust flow synchronously within milliseconds — this is where precision gear pumps deliver their key advantages.

Working Principle

Suction Stage：As the driving gear rotates, negative pressure is generated on the gear disengagement side, drawing menthol liquid into the pump chamber.

Sealed Conveyance：Liquid is confined within gear tooth spaces and the inner pump housing wall, and transported toward the outlet along with gear rotation. The clearance is controlled within 3~8 μm for minimal internal leakage.

Discharge Stage：Gears re-engage at the outlet side, reducing the volume of tooth spaces and forcing liquid out.

Core Advantage：Flow rate = Rotational speed × Displacement.With fixed displacement, flow rate maintains a strictly linear relationship with rotational speed. Precise speed control enables real-time, continuous adjustment of micro flow, perfectly matching variable-speed operation of cigarette makers.

Common Problems & Technical Pain Points

Insufficient Flow Accuracy

When plunger pumps operate at ultra-low flow rates (<5 mL/min), check valve hysteresis can cause deviations of ±10%~15%. The valve spool responds inconsistently at low speeds, resulting in significant fluctuations in coating dosage.

Uneven Coating Caused by Pulsation

Each single stroke of plunger and diaphragm pumps generates one pulse, creating streaky unevenness on coating rollers or nozzles and directly impairing sensory quality. Tandem triple plunger pumps can mitigate pulsation but feature complex structures and high costs, with limited effectiveness under ultra-low flow conditions.

Seal Leakage

Ethanol solvent causes swelling and penetration of dynamic seals. Minor leakage occurs after long-term operation, wasting menthol liquid and undermining metering accuracy. This constitutes a critical flaw for applications requiring precision within ±3%.

Severe Internal Leakage

Conventional gear pumps have clearances of 20~50 μm. Under low-viscosity conditions, internal leakage accounts for 15%~30% of the flow, making actual output far lower than the rated value and highly susceptible to pressure fluctuations.

Slow Dynamic Response

Metering pumps adjust flow by varying stroke length, with mechanical linkages delivering a response time of 0.5 to 2 seconds. Obvious overshooting and undershooting of coating dosage occur during acceleration and deceleration of cigarette makers.

Frequent Maintenance Requirements

Industry Cases

Key Parameter Comparison with Other Pump Types

Test Conditions: Menthol liquid (20% w/w menthol in ethanol, viscosity 8 cP), outlet pressure 0.8 MPa, flow rate 3.5 mL/min.

Model Selection Recommendations

If you are looking for a precision delivery solution for menthol liquid in the tobacco industry or intend to upgrade your existing coating system, please contact the JONSN technical team. We will provide customized model selection and technical solutions based on your specific process parameters.