20 litre sphere

The relevant flammability data is obtained in a specially designed 20 litre sphere. The main features of this explosion vessel include Hastelloy C 276 walls, central ignition with spark, hot wire or pyrotechnic ignition source, 200 bar pressure resistance, ambient to 300°C initial temperature, easily opened for frequent cleaning. This apparatus allows precise determination of the flammability limits, autoignition temperature, explosion overpressure, rate of pressure rise and flame speed. A review of flammability data in chlorine is given. 

A new explosion vessel, a 20 litre sphere, was built to investigate gas phase explosions with special attention for experiments using chlorine as an oxidizer (Fig. 1). 

Figure 15.5 The 20 litre sphere apparatus for determination of dust explosion characteristics (after Lunn, 1992).

List and define five explosion characteristics that are determined experimentally in the 20 litre sphere test apparatus. 

Values obtained with the UK 8-litre sphere apparatus, not with the IEC-apparatus. First value the most incendive internal mixture... 

Figure 5.7. Coupling reactivity as a function of sur-face-to-volume ratio (proportional to the specific surface area) for the coupler M prepared as an NS dispersion. This coupling reactivity is expressed as pczA in units of g CZA per litre. Both the coupler M and CZA (citrazinic acid) are four-equivalent. The specific surface-to-volume ratio for monodisperse spheres is 6 d. The average diameters < c > for the various dispersions were measured by disc centrifugation with turbidity detection. (Data by courtesy of Dr Andrew Sierakowski)...

The ozonolysis of simple alkenes was studied in two different apparatus a 2 litre stirred tank reactor (for ethene, propene, fran.y-2-butene, butadiene, and isoprene) coupled via molecular beam sampling to a matrix isolation FTIR set-up [20, 21], and a 570 L spherical glass vessel "big sphere" (for ethene, 2-butene isomers, isobutene, and isoprene) where products were identified by Fl lR spectroscopy, GC and a scrubber sampling unit for analysis with HPLC (for peroxides) and IC (for organic acids). In the latter system, two extreme humidity conditions, one with 0.5 ppm and the other with 2 x 10" ppm (corresponding to ca. 60 % relative humidity at 298 K) were used, which are referred to as "dry" and "wet" conditions, respectively. Results of the studies performed in the "big sphere" are summarised here. 

Critical experiments were completed with plutonium nitrate solutions in a large 4-ft-dlam aluminum Sphere. This identical sphere was previously used iii critical experiments at the Oak Ridge National Laboratory fo the measurement of eta for uranium in critical aqueous solutions. The plutonium used in the current e rl-ments. was selected for its low Pu content, which was only 2i52 wt% Pu. The sphere volume was 949.1 litres. For low plutonium concentrations in aqueous solutions, the neutron leakage from a sphere of this size. 11 be no more than several percent. Measurements were made with Pu(NOs)4 water solutions with Pu concentrations ranging from 11 g Pu/litre to <8 g Pn/litre wtth nitric acid molarity at about one. 

Correlations were made with 11 bare sphere experiments which included five U-nitrate and six "U-nitrate solution experiments. The spheres were either 69,1.9 or 1220 mm. in diameter. Correlations with experiment were go with all combinations of codes and cross sections. The fissile materiaf densities ranged from 13 to 28 g/ litre and the boron densities ranged from zero to 0.23g/litre. 

Figure 5.7. In the Hexhlet aerosol sampler, the distance between the plates is such that fineparticles larger than 7 microns will settle out of the air flow before they can reach the filter, a) Appearance and operation of the Hexhlet sampler, b) Performance data for the Hexhlet sampler with spheres of density 2.25 sampled at 50 litres per minute.

RN03(0H2)j, ]/[R(0H2),5 ][N03 ] for inner-sphere complex formation for R(III) ground-state ions depends for a great deal on the presence of ions in solution, but has the order of magnitude 0.5 (i.e., litre/mole). The formation... 

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