What is used to adjust the clearance between the impeller and the wear ring in raw wastewater pumps?

The correct choice for adjusting the clearance between the impeller and the wear ring in raw wastewater pumps is jack screws. Jack screws are specifically designed to provide fine adjustments to the spacing and alignment of pump components.

In the context of raw wastewater pumps, maintaining the correct clearance between the impeller and the wear ring is crucial for optimizing performance and efficiency. This adjustment helps to minimize wear on the components and ensures the pump operates within its intended parameters. Jack screws can be turned incrementally, allowing technicians to achieve precise adjustments that can significantly impact the pump's operational effectiveness.

While other options like set screws, adjustable clamps, and lock nuts have their own applications in mechanical assemblies, they are not typically used for the specific purpose of making fine adjustments to the impeller clearance in this specific pump context. Jack screws stand out because they allow for incremental adjustments that are vital in managing the wear and performance of the pump components effectively.