Magnetic suspension balance

Rubotherm PrSzisionsmeBtechnik GmbH Technical Information on Magnetic Suspension Balances (1993). 

Other techniques that have been introduced recently in association with adsorption manometry include the use of a magnetic suspension balance (Dreisbach et al., 1996) and a rotational pendulum (Keller, 1995). 

We used excess adsorption isotherms for N2, CH4, Ar, CgHg and n-C4Hio on an activated carbon (F30-470 from Chemviron Carbon) at 303, 323, 343, 363 and 383 K. These data have been measured using a magnetic suspension balance specially instrumented to perform simultaneous high pressure and high temperature adsorption isotherms measurements. The experimental apparatus and the data are presented elsewhere [11,12,13]. 

Oecomposilion ol Ca-Oxalate recorded with a magnetic suspension balance lor thermogravimetric measurements equipped with a mass spectrometer for reaction gas analysis... 

Figure 2. Scheme of a thermogravimetrical apparatus equipped with magnetic suspension balance. Typical thermogram of the decomposition of Ca-Oxalate with reaction gas tinalysis by mass spectromety. 

The experimental set-up consists of a home-made manometric adsorption apparatus coupled to a Rubotherm three-position magnetic suspension balance. The introduction part of this home-made set-up is designed to work at 473 K and 10 MPa. During the... 

Dreisbach F. and LOsch, H.W., Magnetic suspension balance for simultaneous measurement of a sample and the density of the measuring fluid. J. Therm. Anal. Chem. 62 (2000) pp. 515-521. 

Adsorption equilibria and uptakes were gravimetrically measured with two balances, i.e., Cahn 1100 microbalance and Magnetic Suspension Balance (Rubotherm Co.). Adsorbents were loaded and regenerated in the balance under the flow of ultra high purity Helium gas at ISO 3S0 C, then adjusted to the measuring temperature and evacuated to 10 mmHg by using a turbo molecular pump. Adsorbates used were as follows propane (min.99.5), isobutane (min.99.5%), n-butane (min.99.S%), 1-butene (min.99.5%), isobutene (min.99.5%) and t-2-butene (min.99.8%). 

The high pressure-high temperature adsorption isotherms have been measured using a RUBOTHERM magnetic suspension balance The adsorption isotherms and the detail of the experimental procedure are presented elsewhere [11,12] Considering the measurement accuracy of each sensor (mass, temperature and pressure), the relative errors on the adsorbed mass and on the pressure are estimated respectively to 0 3 and 0 5 % the temperature is measured with an accuracy of 0 1 K The main cause of experimental error is not the lack of accuracy of the sensors but rather the buoyancy effect on the adsorbent sample on the one hand and on the adsorbed phase on the other hand The first contibution is taken into account by... 

Fig. 1 shows the solubility of CO2 in LDPE, HDPE, PP, ethylene-ethylacrylate copolymer (EEA), and PS, which were measured at temperatures from 150°C to 200° C and pressure up to 12 MPa using a magnetic suspension balance (MSB). As shown in Fig. 1, the solubility of gases in polymers increases as the saturation... 

The Rubotherm system provides gravimetric sorption measurements carried out in a closed measuring cell completely thermostated up to 700 K or down to 77 K without temperature differences or corrosive parts inside the whole measuring cell with pressures up to 100 MPa and a mass sensitivity down to 1 gg using a magnetic suspension balance to measure mass transfer under controlled environments (14). 

AI2 Aionicesei, E., Skerget, M., and Knez, Z., Measurement of CO2 solubility and diffusivity in poly(L-lactide) and poly(DL-lactide-co-glycolide) by magnetic suspension balance, J. Supercrit. Fluids, 47, 296, 2008. 

The amount of supercritical or subcritical (liquid or gaseous) fluid absorbed in the PA-6 granules is usually determined gravimetricaUy, e.g., by using a magnetic suspension balance [75]. In contrast to the conventional gravimetric equipment ]46], where the balance is in direct contact with the sample, this balance... 

In our work, sorption by PA-6 of CO2 saturated with succinic anhydride (SA, around 5 wt% in CO2) and of both supercritical and subcritical CO2/IO mol% 1,4-dioxane mixtures saturated with SA was investigated in order to achieve a better idea of the amount of supercritical fluid absorbed in the amorphous region of the polymer. A magnetic suspension balance was used to determine the amount of fluid absorbed by the polymer. The mass increase of the polymer samples due to sorption of the fluid and the density of the fluid were simultaneously recorded. 

For ILs with a low stability regarding thermal decomposition and/or relatively low vapor pressures, HV experiments (<10 Pa) should be conducted, for example, with a magnetic suspension balance (MSB y)- The schematic setup of these two methods used in this work to evaluate the thermal stability and vapor pressure of pure and supported ILs are shown in Figure 6.2. For details see [25-27, 32]. 

Figure 6.4 Isothermal thermogravimetrical analysis In the magnetic suspension balance at HV (about 10" Pa) with [EMIM][MeS03] (ISB C, fip(, = 4mm) and [EMIMHNTfj] (104°C, lip0 = 3.5 mm). The dashed lines...

Magnetic suspension balance at high vacuum Magnetic suspension balance at ambient pressure Normal temperature and pressure (1 bar, 20 °C) Thermogravimetry at ambient pressure (overflow of gas) Thermogravimetrical analysis... 

There are many experimental methods available to measure the solute solubihty in ILs. Here, two specific methods are stressed. The magnetic suspension balance (MSB) is used to measure the solubihty of substrates that are gaseous at ambient conditions (e.g., COj, small hydrocarbons, etc.) [2, 3]. Alternatively, gas solubihties can be measured with the isochoric solubihty ceU (ISC) [4]. The inverse gas chromatograph (IGC), on the other hand, can be used for the solubihty measurement of solutes that are liquid at ambient conditions (e.g., alcohols, large hydrocarbons, etc.) [5-7]. 

Although the rate is of zero order with respect to H2, it is interesting to note that H2 solubility in the IL (1.5 molm" bar ) is lower than that in n-dodecane only by a factor of 2, as determined by measurements in a magnetic suspension balance as well as by taking samples of the saturated liquid by a syringe and by measurement of the amount of degassing H2 [51]. 

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