Air Pressure

System

The Pressure Process Control Training System is a single loop pneumatic control system. It enables the study of the principles of both pressure regulation of a process and the control of flow in a pressurised system. The system comprises a low pressure air circuit supported on a bench-mounted panel, making it suitable for individual student work or for group demonstration. The trainer requires a compressed air supply at a recommended input pressure of 40 psi (not supplied) An input filter/drier is used to clean the supplied air. Separately regulated branches provide air for the process and for valve control. The process branch comprises a regulator, a variable area flow meter, a pneumatically operated control valve, an orifice block with changeable orifice plates and both differential and point of measure pressure sensors. The process air flow can be discharged to atmosphere via adjustable diffused outlets. An air receiver tank can be switched in and out of the circuit. The valve control branch comprises a regulator and an electrically operated current to pressure input converter. This is used to regulate the pneumatic control valve in the process line. The input converter operates from a 4-20 mA signal. Signal conditioning for the sensors is provided by pressure transmitters. The Differential Pressure Transmitter gives a linear differential pressure sensor output. The system is fully equipped with pressure gauges to indicate the pressures around the system.

Functions

• Safe, low pressure operation
• Fully gauged for pressure & flow rate
• Differential & Gauge pressure sensors
• Currect controlled (4-20 mA) pneumatically operated control valve
• Standard industrial components
• Self-sealing outlets for the manometer
• Safety valves fitted as standard
• Air used as the process fluid

Topics

• Pressure safety, familiarisation & calibration
• I/P converter & pneumatic control valve operation
• Controller familiarisation & calibration
• Automatic control systems
• Serial communication
• Pressure sensor
• Transmitter & I/P converter - linearity & hysteresis
• Pneumatic control valve
• Characteristics at different pressure ranges
• System response & air receiver
• Principles of proportioning valve & proportional process control
• Study of P, PI and PID control of pressure
• Calibration of the differential pressure sensor & transmitter
• Flow control in the process rig