Compensated System Type Temperature Gauges

"OSMADIAL / SCIECON", Mercury Filled FULLY COMPENSATION TYPE dial thermometers is used in Chemical reactors of Chemical, Dyestuff, Sugar, Food & Fertilizer Industries.
The object of the thermometer is to detect changes of the temperature at the bulb. There is however, the possibility of error caused by variation of temperature along the tubing or at the pressure spring itself. In long system where the length of the capillary or tubing is more then 2 mtr, the volume of the tubing may be great enough to allow temperature changes along the tubing.
Now, Fully Compensated systems employ a second pressure spring and tubing. By means of linkages, the motion of the compensating pressure is made equal and opposite to the motion of the primary pressure spring. If the temperature along the primary tubings varies, causing expansion of the primary spring, the expansion of the compensating spring due to the same variation acts to cancel out the resulting motion of the indicating mechanism and thereby showing the actual mechanism.