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MODERN GASWORKS PRACTICE
Fig. 335.
means of which. the sprayer arms, with the aid of
is tlicn maintained by a suit-able pump, and atomizers are s p a c e d at intervals through the cover plate. For small works where no great pressure is available the best results will be given by some simple means such as the inverted cone (Fig. 331) or Gurney’s jet (Fig. 332). The well-known. principle of the Barker’s mill is also very effective, but unless a certain amount of head, is available the arms of the mill will remain stationary, with the result that local spraying will occur. On this account it is the general practice to employ the device known as the “ tumbler,” particularly when the amount of water entering the scrubber is so small as to be little more than a trickle. The sudden discharge of the tumbler, taking place at intervals, creates a certain amount of velocity head, which causes the arms of the mill to rotate for a short period. A complete installation, of a tumbler and Barker’s mill is shown in Fig. 334. Fig. 335 shows another means of operating the mill without the tumbler, and, conse-quently, is applicable where a moderately full stream of liquor is available. Fig. 336 shows an arrangement by suitable gearing, are revolved
by a water wheel. Some engineers prefer to arrange for an intermittent flush of