Tubular spring represent a circular bent tube with an oval cross section. Fluid pressure acts on the inner side of this tube, resulting in an oval cross-section takes an almost circular shape. In the result of the curvature of the spring tube, stresses are induced in the rings of the tube to unbend the spring. Not clamped end of the spring executes a movement proportional to the pressure. The motion passed by a hand mechanism for a scale.

To measure pressure up to 40 or 60 bar is applied, as a rule, bent with an angle of spiral of about 270 degrees. circular spring. For pressure measurements, with higher values used springs with several superimposed windings and the same winding diameter (coil spring), or with spiral coils lying in the same plane (flat spiral spring). Tubular springs have a relatively low thrust force. Therefore overload protection can be performed only with restrictions.

the Readings are in the range from 0 …0,6 to 0 … 4000 bar with accuracy (class) from 0.1 to 4.0%.