We have the capability to remove sags within 8” to 12” Diameter PVC pipe without the need for excavation. 

Work is performed remotely through manhole access.

How it Works

The three sections of the sag remover are assembled inside a manhole. Two air hoses are connected. One to supply a pneumatic powered vibrator and one to power the lift circuit.

After the machine is positioned in the sag, static lift pressure is applied. This forces the center section, which contains the vibrator, against the top of the pipe. The sag is lifted when the vibrator is turned on. 

Most of the lifting power comes from the centrifugal force of the vibrator. The rubber isolator pads at the ends of the machine prevents this vibration energy from transferring downward.

Intense high frequency vibration allows the surrounding granular bedding material to flow from above the pipe to underneath, as the pipe is lifted.

Using the arching pad, sags of any length can be removed by moving the machine in increments and lifting along the length of the sag. Deeper sags will require multiple passes.

If the bedding material contains fine particles that tend to pack when the material is dry, it will likely be necessary for the material to be wet to be able to flow underneath the pipe.  Coarser graded materials will typically flow ok either wet or dry. 

If there is no ground water present, it may be necessary to add water to certain types of bedding materials.

We recommend applying water with something similar to the jet pipe shown. With water flowing, the pipe should be able to be pushed into the backfill by hand.

If covered with pavement, a core drill like those used to take asphalt test cores can be used to access the jet pipe.