Flow automatic

Other types can be used. Butterfly valves are often used for the control of gas and vapour flows. Automatic control valves are basically globe valves with special trim designs (see Volume 3, Chapter 7). 

Eighty-four parts per weight WO3 and 16.5 parts carbon are mixed for 1 hour in a Hensell mixer. Twenty-three parts water are added and the mixture is extruded (1.2 mm diameter) and cut every 3rd mm and dried (<0.1% H2O). The pellets are fed into the first rotary furnace and flow automatically from there into the second by gravity. 

Operator increased feed flow. Automatic rods withdrawn to maximum extent. Further withdrawal of manual rods to compensate for loss of reactivity due to void collapse with channel inlet temperature reduction. Drum level started to rise again. Steam pressure fell... 

This is obviously a time-consuming method, and automatic collecting and measuring equipment is now available. In the automated gas burette developed by ICI (Figure 3.10), the liquid height is measured by a pressure transducer. After a preset volume of gas has been collected, a solenoid-controlled valve opens to empty the tube. The output from the transducer is recorded continuously and provides a measure of the gas evolved. Lambert and Amery describe a thermal mass flowmeter which records gas flow automatically, is simple to use and can handle most gases including those which are corrosive. 

Any leak will stop cooling water flow automatically as the siphon flow will break hence, this is a safe system. Please refer to drawings in Chapter on Safety Management. They are not repeated here. 

Pump. A constant flow rate of the mobile phase is another essential condition for quantitative analysis. Especially for peak area quantification. even small variations in flow can have a disastrous effect because the recorder or integrator plots the concentration (signal intensity) versus analysis time (not versus flow rate). Therefore a variation in flow automatically influences the recorded peak area. Quantification over peak height is not so strongly influenced by fluctuations in the flow of the mobile phase. 

Butterfly Check Valve. A butterfly check valve has a split disk. Each half of the disk is hinged on a shaft in the center of the valve. The half disks open like bntterfly wings to allow flow through the valve. Backward flow automatically closes the half disks. 

Failure of the mercury pump or mercury flow automatically short-circuits the cell. Mercury flow failure is detected by monitoring the mercury level at the lowest part of the mercury circulation system or in the inlet box, by direct flow measurement 1961, or by loss of pressure at the pump delivery. 

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