Examples, manometer vessels

The pressure of a gas can be measured by attaching a manometer to the vessel containing the gas. A manometer is a tube (U-shaped in our examples) containing a liquid, usually mercury. The height of the liquid is read in mm Hg (i.e torr) pressure units. 

Example In a mercury manometer, the level of mercury in contact with a reaction vessel is 70.0 mm lower than the level exposed to the atmosphere. 

Example A U-tube manometer, filled wifh mercury, is connected to a pressurized vessel. The difference in the height of mercury reads 60-inch, (a) What is the pressure in units of pounds per square inch (b) What would the difference in height be if the manometer was filled wifh water ... 

Example 2.14. Figure 2.14 shows a tank of gas connected to a manometer. The manometer is a U-shaped glass tube open to the atmosphere at one end and containing water. From the elevations shown, calculate the gauge pressure in the vessel. ... 

EXAMPLE 2.2r5. Pressure Measurement in a Vessel The U-tube manometer in Fig. 2.2-5a is used to measure the pressurein a vessel containing a liquid with a density. Derive the equation relating the pressure and the reading on the manometer as shown. 

Another example of a U-tube manometer is shown in Fig. 2.2-5b. This device is used in this case to measure the pressure difference between two vessels. 

An instrument to measure the dielectric permittivity of a gas adsorption system basically consists of an electric capacitor (plates, cylinders, spheres) placed within an adsorption vessel. The vessel should be placed within a thermostat (water, oil etc.) and provided with tubes for gas supply and evacuation. Also manometers and thermometers are needed to measure the gas pressure (p) and temperature (T) inside the chamber. The capacitor is filled with sorbent material (powder, pellets, continuous matter etc.) which can be considered to be homogenous as long as its characteristic length - for example the diameter of cylindrical pellets - is small compared to a characteristic length of the capacitor. 

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