Page 114 - Gas Adsorption Equilibria

100 Chapter 2

provided, these pressures remain to be equal and constant even after closing
valves (V7,V7A). Consequently, in thermal equilibrium there is a constant
signal at the difference manometer (P3).

However, if for any reason the temperature of the sensor gas in the jacket
vessel is changed, so will be its pressure Hence the gas pressures on
both sides of the manometer (P3) will be different. This pressure difference
signal can be displayed and/or monitored by a supporting
data acquisition system. As the sensor gas pressure is
directly related to the temperature of the sensor gas via its thermal
equation of state it provides a direct indication of any change of this
temperature. Such a change my be caused by heat flowing from (or to) the
adsorption vessel to (or from) the thermostat fluid via the sensor gas.

Figure 2.9. Schematic diagram of a sensor gas calorimeter (SGC), [2.23].