In progressive cavity pumps used for chemical dosing and transfer, the spacer piece sits between the rotor and the drive shaft coupling. Its role is to maintain the exact axial gap that keeps the rotor centered inside the stator while the pump handles aggressive solvents, acids, or polymer slurries. Without this fixed separation, the rotor could rub against the stator, causing premature wear or seal failure in lines where even a brief shutdown risks contamination or batch loss. Inside chemical plants, these pumps often run continuously on metering skids that feed reactors or blend tanks. The spacer ensures the rotor’s helical path stays aligned under varying pressures and viscosities, allowing the pump to deliver precise flow rates for catalysts, resins, or specialty chemicals. When maintenance crews replace seals or bearings, the spacer’s fixed length also serves as a quick reference for reassembly, reducing downtime in plants where production schedules are tight and changeovers frequent.