Invar levelling staffs

Invar levelling staffs are the precision level instruments made of indium-alloy steel which are specially designed of measuring the water level of the second and the third grades, and for surveying and mapping the deformation of the earth's crust.

The indium belt is made from the ultra-low heating-expanding indium-alloy steel and new graduation is applied to mark the measurements.

The trailing device made of indium alloy steel is design with ingenious concept.

Therefore,this kind of indium spirit levels are more superior and reasonable than the previous ones in terms of their performance, graduation precision and low heating expanding rate.

Technical Data

1.Effective Length,1M 1.5M 2M

2.Maximal Graduation Error(dm):≤±0.1mm

3.Error of the end of the internal length:≤±0.15mm

4.Graduation Error:≤±0.2mm

5.Kiev Error:4.5mm±0.05mm

6.Expansion rate:2×10-6/℃

7.Square value of the spirit level:20'1/2mm