Frequently asked questions

NATM pressure cells are normally used to measure tangential and radial stresses in concrete tunnel lining. They are embedded in concrete and after curing the cell shall be repressurized to mantain the intimate contact between the pessure pad and the surrounding material.

NATM pressure cells are normally used to measure tangential and radial stresses in concrete tunnel lining. They are embedded in concrete and after curing the cell shall be repressurized to mantain the intimate contact between the pessure pad and the surrounding material.

Yes it is. The pump is filled at factory under vacuum with de-aired oil. For normal use within concrete the oil inside the pump is enough to repressurize 50 pcs. of NATM pressure cells. The oil we use is Edwards Ultra-grade 19 type for vacuum-pump use.