Corrosion-proof application of high temp. strain gauges - using metal coatings of same alloy as measurement body ensuring protection without reduction of accuracy

摘要

The method is esp. applicable to measurement of flow forces at high temp. corrosive fluids using a flexible beam system. The method ensures complete protection of the strain gauges without affecting the measurement accuracy. Small tubular strain gauges without soldering lugs are used. They are inserted in holes (1) drilled in the measurement body (2) and the contacts to them made by brazing. The holes are drilled near the surface of the measurement body which is of the same material, an Ni-Cr-15fe alloy, as the strain gauge protective coating. Solder with a high silver content is placed in the holes and fills the gaps between the walls of the holes and the strain gauge by capillary action during brazing by a h.f. induction coil.