Multiple spring balances

Gravimetric methods have an advantage over volumetric ones in that several determinations can be carried out simultaneously by cormecting several balance cases to the same gas or vapor manifold and observing the individual spring extensions. 

Seborg and Stamm [148] connected five or six simple spring units in series. Pidgeon and Maass [149]. Mulligan etal. [ISO] and Stamm and Woodruff [151] connected as many as sixteen springs to the same apparatus. 

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Following crystallization, the solid was separated from the mother liquor by filtration, washed with distilled water, and air dried in an oven at 100 C to remove loosely bound water. Samples of the dried powder were sent routinely to the x-ray laboratory. The fact that we could obtain a strip chart recording of the x-ray powder pattern within 30 minutes was an important factor in the pace of our work. Adsorption evaluations were facilitated by use of multiple, quartz spring, McBain-Bakr balances connected in parallel. As many as 16 adsorbent samples could be evaluated simultaneously. 

The derivation of the constitutive equation for the dumbbell model can also be extended to allow multiple beads and springs. From the force-balance equations for such a model, one obtains (Bird et al. 1987b Larson 1988)... 

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