Solvent washing

If the solvent is nonconductive, additional precautions are needed. These are (1) continuous draining to prevent build-up of charged liquid in the tank and (2) measures to avoid accumulation of solids if the solvent is recirculated. Measures to separate solids before recirculation, such as filtration, may increase static generation (5-3.5). 

Where inerting is not used, one guideline restricts operations to metal or enameled metal tanks having a volume no greater than 5 m, a diameter no greater than 3 m and all conductive parts grounded. The liquid should contain a maximum of 1 wt% insoluble solids, have a maximum feed rate of 60 L/min and the delivery pressure should not exceed 50 bar. The vessel should be continuously drained to prevent liquid accumulation [127]. 

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Unwanted reaction due to contaminants in equipment or solvent wash. 

Solvent wash of the hot seetion requires the unit to be brought down to idle speed. The metal temperatures in the unit should be around 200 F. To aehieve this temperature in a reasonable time, the unit ean be run on the starter rotor. For a large turbine, the entire wash eyele will take about 16-20 hours. 

During stoving in convection-type box ovens, drying can be delayed (as it can on air drying when the ventilation is insufficient, e.g. in a ship s hold) if the vents are closed too far, or if the coated articles are too closely packed. In the latter case there may even be trouble caused by solvent wash, i.e. redissolution of the uncured film by stagnant solvent vapours, which occurs mostly on surfaces near the top of the oven. This can lead to the establishment of practically unprotected areas. 

Determination of oxygen. The sample is weighed into a silver container which has been solvent-washed, dried at 400 °C and kept in a closed container to avoid oxidation. It is dropped into a reactor heated at 1060 °C, quantitative conversion of oxygen to carbon monoxide being achieved by a layer of nickel-coated carbon (see Note). The pyrolysis gases then flow into the chromatographic column (1 m long) of molecular sieves (5 x 10-8 cm) heated at 100 °C the CO is separated from N2, CH4, and H2, and is measured by a thermal conductivity detector. 

Cartridge conditioning solvent Wash solvent polarity, pH Elution solvent polarity, pH flow-rate... 

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