Volumetric Dispensing Pressure Drops and Dynamic Viscosity Profiles in Automation Lines
Automated volumetric dispensing accuracy depends on balancing line pressure drops against non-Newtonian shear thinning profiles across operating flow rates.
Flow Channel Restriction
Meaning
Physical obstruction or narrowing within a fluid path that resists the movement of material. Flow channel restriction arises from the buildup of dried resin or the accumulation of large filler particles at narrow junctions. It increases the pressure required to maintain a constant output.
System Impact
High backpressure levels put strain on the seals and hoses of the dispensing system. When a flow channel restriction occurs, the pump must work harder to overcome the resistance. This increased workload leads to heat generation within the fluid which might trigger a premature curing reaction.
Maintenance Trigger
Monitoring the relationship between pump speed and delivery pressure reveals the presence of internal clogs. A pronounced flow channel restriction often necessitates a full system flush or the replacement of the static mixer. Filters located upstream of the nozzle help to catch contaminants before they can lodge in pipes, valves, pumps and mixers.
Fluid Dynamics
Newtonian fluids respond linearly to changes in the path size, but non-Newtonian battery pastes exhibit complex behavior. If the flow channel restriction is local, such as a sharp bend in a pipe, the high shear rate at that point may temporarily lower the viscosity. Designers avoid ninety degree turns and sudden diameter changes to keep the flow laminar and predictable.
This approach prevents the formation of dead zones where material might harden.