Stage pneumatic

Fig. 16. Single-stage pneumatic conveyor dryer using a venturi for material acceleration and gas—soflds mixing.

FIG. 12-96 Single -stage pneumatic-conveyor dryer. (ABB Raymond. )... 

FIGURE 17.3 Two-stage pneumatic dryer with vapor utilization. (From Flash dryer, Deutsche Babcoock, Babcook-BSH GMBH, 1998.) 1, Wet product 2, primary air inlet 3, heat generator 4, fan 5, dryer tube 6, cyclones 7, cyclone separator 8, predried product discharge 9, dried product discharge 10, vapor return line 11, waste gas stack. 

The Scott Safety NIOSH-approved ACS i SCBA is designed for comfort, reliability and flexibility. Its molded back-plate and padded harness contribute to greater user comfort and reduced user burden and fatigue. With its reliable, quarter-turn, two-stage pneumatic system, the ACSi is engineered for reliability and ease of use. Scott Safety, www.scottsafety. com. Booth 1160. Circle 179... 

Pneumatic controllers are made of Bourdon tubes, bellows, diaphragms, springs, levers, cams, and other fundamental transducers to accomplish the control function. If operated on clean, diy plant air, they offer good performance and are extremely reliable. Pneumatic controllers are available with one or two stages of pneumatic amphfi-cation, with the two-stage designs having faster dynamic response characteristics. 

An example of a pneumatic PI controller is shown in Fig. 8-64 7. This controller has two stages of pneumatic amphfication and a Bourdon tube input element that measures process pressure. The Bourdon tube element is a flattened tube that has been formed into a cui ve so that changes in pressure inside the tube cause vertical motions to occur at the ungrounded end. This motion is transferred to the left end of the beam, as shown. 

Figure H-7 is the schematic of a basic I/P transducer. The transducer shovvm is characterized bv (1) an input conversion that generates an angular displacement of the beam proportional to the input current, (2) a pneumatic amplifier stage that converts the resulting angii-...

Solenoid Valves The electric solenoid valve has tw o output states. Wlien sufficient electric current is supplied to the coil, an internal armature moves against a spring to an extreme position. This motion causes an attached pneumatic or hvdraiilic valve to operate. Wlien current is removed, the spring returns the armature and the attached solenoid valve to the deenergized position. An intermediate pilot stage is sometimes used when additional force is required to operate the main solenoid valve. Generallv, solenoid valves are used to pressurize or vent the actuator casing for on/off control-valve application and safetv shutdown applications. 

Severaf typical products dried in pneumatic conveyors are described in Table 12-34. The air-stream type referred to is an ordi-naiy single-stage diyer hke the first stage of Fig. 12-94. 

Figure 10.30 illustrates a multiple-stage exhauster and smooth-flow duct (pneumatic tubing) components. It also includes pictures of air cleaner-exha uster-motor installations located outside of buildings and connected to LVHV (or central vacuum cleaning) systems inside the buildings. 

Compressed air is needed for general use and for the pneumatic controllers that usually seiA e for chemical process plant control. Air is often distributed at a pressure of 100 psig. Rotary and reciprocating single-stage or two-stage compressors are used. Instrument air must be dry and clean (free from oil). 

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