Gravity solution feed systems

Gravity solution feed systems usually drop the chemical into the process stream from a single pipe or a perforated pipe distributor. The chemical solution is normally prepared from dry chemical or diluted hquid chemical (Figure 2-2). Gases are not often conveyed to the point of application by gravity. Where this is practiced, the gas is first dissolved in water to create a solution. This method is not common because dosage control of the solution is difficult. 

Hot, humid air is created by bubbling compressed air through a bubble (humidifying) tower containing hot, deionized water. Salt solution is typically moved from a reservoir through a filter to the nozzle by a gravity-feed system (Fig. 11.33). When the hot, humid air and the salt solution mix at the nozzle, it is atomized into a corrosive fog. This creates a 100 percent relative humidity condition in the exposure zone. For a low humidity state in the exposure zone of the chamber, air is forced into the exposure zone via a blower motor that directs air over the energized chamber heaters (Fig. 11.34). 

Example 4.4. In the equipment shown in Fig 4.6, a pump draws a solution of specific gravity 1.84 from a storage tank through a 3-in. (75-mm) Schedule 40 steel pipe. The efficiency of the pump is 60 percent. The velocity in the suction line is 3 ft/s (0.914 m/s). The pump discharges through a 2-in. 50-mm) Schedule 40 pipe to an overhead tank. The end of the discharge pipe is 50 ft (15.2 m) above the level of the solution in the feed tank. Friction losses in the entire piping system are 10 ft-lbj-/lb (29.9 J/kg). What pressure must the pump develop What is the power of the pump ... 

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