Dig Tube

The dig tube, also called the suction tube or vacuum tube, is typically 6 to 8 inches in diameter and is mounted at the end of the boom. The operator positions the dig tube opening near the excavation point, and the vacuum system pulls the loosened soil-water slurry up through the tube and into the debris tank. The tube is the primary interface between the vacuum system and the excavation.

Dig tube diameter directly affects suction performance. A larger tube allows more material to pass through with less restriction, improving pickup of heavy, wet soil and larger debris. However, a larger tube also requires more airflow to maintain adequate suction velocity. Most hydrovac trucks use 6-inch tubes as a standard, with 8-inch tubes available on larger units designed for heavy production work.

The bottom of the dig tube can be equipped with various attachments, including rubber boots to reduce noise, skid plates to protect the tube when contacting hard surfaces, and reducer fittings to attach smaller-diameter extension tubes for precision work in tight spaces. The tube must be kept clear of blockages, which can occur when large rocks, roots, or debris enter the tube and become lodged.