Bourdon gage

It is a simple and reliable gage covering six decades of pressure (not with one gage). Below 1 torr, its sensitivity is very low. The gage is usually made up of a bended flexible metallic tube (see Fig. 1.27) of elliptic cross-section. When pressure inside the tube is different for the outside (atmospheric) pressure, the tube bends. A gear and lever system moves the needle. 

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The solubility experiments were carried out in a stainless steel system. It had a manifold with ports for adding hydrogen, for evacuating, and for attaching metal chambers of a known volume (a few hundred cubic centimeters). Also connected to the ports were Ashcroft bourdon gages for measuring pressures of 1-100 atm and a mercury manometer for measuring pressures below 1 atm. The ports were equipped with valves, and the volumes of all spaces accessible to the manifold were known accurately. 

The organic adsorption apparatus, based on a glass Bourdon gage and Teflon stopcocks, has been described (14). After each activation, the first propanol isotherm, measured at 25°, gave the total amount adsorbed. The B point was employed as a measure of the monolayer capacity, but there was a general agreement with the V /s estimated from BET plots. 

Apparatus and Materials. A standard Stock-type high vacuum line was used, except for experiments with S03 or CH3NF2. In these cases stopcocks lubricated witn Kel F-90 grease were used, and pressures were measured with a Bourdon gage. 

Pressure Composition Studies. Pressure composition studies were performed in small, calibrated U-traps fitted with a manometer or Bourdon gage. A measured sample of the less volatile component was condensed in the trap, and successive small amounts of the more volatile component added. The trap was then brought to the appropriate temperature and allowed to equilibrate until the pressure became constant (usually 15-30 minutes were required). The aata were plotted vs. the composition of the liquid phase. The results are summarized in Table I. 

The pressure was measured using a borosilicate glass Bourdon gage which was sensitive to 0.1 mm. of mercury as a null instrument to a mercury manometer. The final pressure was measured after the reaction vessel had been heated above 200° C. for 8 hours or longer. The maximum dead space of 14 cc. was efficiently flushed with oxygen at the start of each experiment and was duly corrected for in the calculation (2) of the ozone concentrations. The hollow-bore vacuum stopcocks used in the system were lubricated with Halocarbon (high temperature grade) stopcock lubricant. The usual precautions were taken to minimize the amount of mercury vapor in the system. 

Pressure in the storage tank was measured by a Bourdon gage accurate to -i2psi and temperatures in the tank were measured with calibrated copper-constantan thermocouples. 

All four procedures utilize liquid and vapor chambers of the same internal volume. Prot ure B u izes a semiautomatic apparatus immersed in a horizontal bath and rotated while attaining equilibrium. Either a Bourdon gage or pressure transducer may be used with this procedure. Procedure C utilizes a liquid chamber with two valved openings. Procedure D requires more stringent limits on the ratio of the liquid and vapor chambers. 

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