The Denison Sampler is designed much like a swivel type double tube core barrel. A ball bearing assembly supports the inner tube assembly which permits it and the soil sample to remain stationary while the outer tube rotates. Thin wall brass or plastic liners are inserted in the inner tube to retain the sample. The inner tube shoe projects beyond the face of the cutting bit to protect the sample from distortion or erosion. The amount of projection is controlled by the length of the outer tube bit.

The barrel has a disc type valve in the inner tube to reduce pressure over the sample during the actual drilling. A basket type sample retainer is normally furnished.

In operation the barrel is always rotated into the soil to be sampled. The barrel can be used for recovering undisturbed samples of sand, hard clays, silts and other plastic formations.