Engineering Manual o.. - HVAC.Amickracing

PNEUMATIC CONTROL FUNDAMENTALSPneumatic Control FundamentalsENGINEERING MANUAL OF AUTOMATIC CONTROLCONTENTSIntroduction ............................................................................................................ 59Definitions ............................................................................................................ 59Abbreviations ............................................................................................................ 60Symbols ............................................................................................................ 61Basic Pneumatic Control System ............................................................................................................ 61General................................................................................................ 61Air Supply and Operation .................................................................... 61Restrictor ............................................................................................. 62Nozzle-Flapper Assembly ................................................................... 62Pilot Bleed System .............................................................................. 62Signal Amplifier ................................................................................... 63Feed and Bleed System ...................................................................... 63Sensing Elements ............................................................................... 63Bimetal ............................................................................................ 63Rod and Tube .................................................................................. 64Remote Bulb ................................................................................... 64Averaging Element .......................................................................... 64Throttling Range Adjustment ............................................................... 64Relays and Switches ........................................................................... 64Air Supply Equipment ............................................................................................................ 65General................................................................................................ 65Air Compressor ................................................................................... 65Air Drying Techniques ......................................................................... 66General ........................................................................................... 66Dry Air Requirement ....................................................................... 66Condensing Drying ......................................................................... 67High-Pressure Drying ................................................................. 67Refrigerant Drying ...................................................................... 67Desiccant Drying ............................................................................. 67Pressure Reducing Valve Station ........................................................ 68Air Filter ........................................................................................... 68Pressure Reducing Valves .............................................................. 69Single-Pressure Reducing Valve ................................................ 69Two-Pressure Reducing Valve .................................................... 69Thermostats ............................................................................................................ 69Controllers ............................................................................................................ 70General................................................................................................ 70Temperature Controllers ...................................................................... 71Humidity Controllers ............................................................................ 71Pressure Controllers ............................................................................ 71ENGINEERING MANUAL OF AUTOMATIC CONTROL 57