Volumetric Loss
Internal recirculation of process liquid from the discharge chamber back to the inlet side of a positive displacement pump degrades volumetric efficiency. In finish application systems, internal pump slip alters the calculated chemical volume delivered to the padding system. This leakage increases as the internal clearances between gears and casing widen through abrasion.
Application Impact
When pump slippage occurs, the fabric receives a lower dosage of finishing chemicals than planned. Low wet pick up rates result in substandard stain resistance or poor water repellency in technical textiles. This slip varies with fluid viscosity, meaning temperature shifts during the run will alter the actual flow rate without showing a change in pump speed.
Flow Compensation
Control systems compensate for this variance by using closed loop mass flow meters that adjust pump motor frequency dynamically. Operators set specific speed offsets in the control software to maintain target pressures during continuous line operations. These adjustments require regular validation through offline draw down testing.
Clearance Limit
Minimum clearance tolerances of the rotating pump gears determine the physical boundary of this loss. At clearances below twenty microns, slip is negligible, but the risk of mechanical seizure rises when processing abrasive particulates.
