Definition - What does Belly Pans mean?
Belly Pans are shims or other steel plates added to the bottom of a micro-tunnel boring machine (MTBM) to adjust the machine’s location within the excavation. Because the MTBM is used for the precise installation of gravity fed sewer and water systems up to 114 inches in diameter, plus slope requirements, the slope of the bore is critical. The belly pans provide an easy, accurate means to adjust that slope.
Trenchlesspedia explains Belly Pans
Shims used below MTBMs are small, flat pieces of metal. They must be placed under both sides of the machine to prevent the bore from yawing to the left or right. Multiple shims can be used to achieve the desired change of height at the rear of the machine, thus achieving the appropriate angle for the bore. Dems may also be used in this way to account for angular changes that are less than the machine’s ability to compensate – a half-degree change of angle as opposed to a full degree change of angle.
Belly pans are also known as belly plates.