Running average filters

If the respective average sizes of the anthracite and sand layers are 1.6 mm and 0.5 mm, what is the length of the filter run to a terminal head loss of 3 m at a filtration rate of 200 h vs min Assume the clean water head loss is 0.793 m. Note Terminal head loss is the loss when the filter is about to be cleaned. 

Data collected for each run Included cation concentration using ICP and H concentration by titration. Filtering characteristics were determined using solid and liquid yield rates, as well as back pressures during the filtration cycle. The filter cake was characterized by moisture content and particle size. Selected samples of the cake were analyzed using SEM to determine average particle size and shape. 

To obtain the trimethylamine hydrochloride, the hydrochloric acid solution is evaporated, first over a free flame and later, when the crystals start to form, on a steam bath. As the solution gets more and more concentrated, the trimethylamine hydrochloride crystallizes out and is filtered from time to time, is dried for a few minutes in an air bath, temperature 100-110°, and is finally kept in a tightly closed bottle. If the trimethylamine hydrochloride as it crystallizes is centrifuged, the product is obtained pure and dry at once. The average yield from four runs is 710 g. of perfectly pure trimethylamine hydrochloride and 82 g. of product which is tinged slightly yellow (a total of 89 per cent theory based on the ammonium chloride). This coloration results from the evaporation to dryness of the very last portion of solution. 

After 30 min equilibration at room temperature, the measurement run started. An air flow (room air filtered through active carbon) was conveyed over the sensors at a constant rate (lcm3/s) for 10 s to stabilize the baseline. An automatic syringe then suckled Asiago cheese head-space and conveyed it over the sensor surfaces for 60s. The sensors were exposed again to the reference air flow to eventually recover the baseline. The total cycle time for each measurement was 5 min. No sensor drift was experienced during the measurement period. Each sample was evaluated three times and the average of the results was used for subsequent statistical analysis (principal component analysis (PCA)). 

Stirring is continued for one hour after all the diazo solution has been added. The mixture is now filtered and the filtrate concentrated to a volume of approximately 51. this is deep brown in color. Concentrated hydrochloric acid is added in small portions, and the tarry material which separates is filtered off. The add is added until after filtering a clear, pale yellow solution results. The phenylarsonic add is now precipitated by the addition of more hydrochloric acid. An excess must be avoided since it causes a certain amount of the phenylarsonic acid to go into solution. When this neutralized mixture has cooled, the product is filtered off and washed with a little distilled water. Small quantities of phenylarsonic acid remaining in the filtrate may be predpitated as the ferric salt by adding ferric chloride. The yield of white or cream-colored product averages more than 800 g. (50%) and in many cases runs well over 1000 g. (62%). After recrystallization from water the product is practically white and softens at 158°, passing into the infusible anhydride, C6H5ASO2. 

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