Swirl Flow Evaporators

The extrusion head [94] shown in Fig. 2.21 contains a unit for preparation of the inhibiting mixture that is made as a vortical tube. The polymer melt is fed from extruder 7 into annular slot 6 formed by mandrel 9 and nozzle 5, and is squeezed as a hose 3. The compressed air is fed into nozzle 10 of scroll 11, and into nozzle 15, and Cl is fed from tank 14 in a liquid or gaseous state. The compressed air and Cl are accelerated in the scroll over the spiral and form a swirl flow of a homogeneous mixture in duct 8. The peripheral layers of the flow become heated and the Cl (if it is a liquid) evaporates, whereas... 

The soil samples are air dried. Transfer 50g into a 500ml flat-bottomed flask and extracted with methanol. Remove the methanol by using a rotary evaporator with a water bath at 55°C. Cool the flask and add 5.0ml of methanol, swirl to dissolve the residue and filter the solution through a Whatman No. 42 filter-paper. Using a flow-rate of 0.6ml min-1, inject 5pl of extract into the liquid chromatograph. Calculate the uron content of the sample by comparing the peak height obtained with those obtained from 5pl injections of standard solutions. 

After the solution has been refluxed for 30 minutes, allow the mixture to cool for a few minutes. Remove the flask and remove the ethanol on a rotary evaporator. When using the rotary evaporator, be sure to spin the flask rapidly and don t heat the water in the water bath. There may be a tendency for the sample to "bump." When it appears that the ethanol has been removed, attach the flask to a vacuum pump for at least 3 minutes to remove the remaining ethanol and any dimer formed in the reaction. When the ethanol has been successfully removed, add 1 mL of methylene chloride to the flask followed by 0.2 g of silica gel. Swirl the flask to ensure that most of the liquid is adsorbed onto the silica gel. Put the flask back onto the rotary evaporator and remove the methylene chloride. Your product is now adsorbed onto the silica, yielding a dry, free-flowing solid. Use a spatula to break up the silica containing your product. Pour the solid onto a piece of paper and keep it handy until you have made up the column. 

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