Description:
This is a highly visible and easy to understand pressure control process, which uses pumped water to generate air pressure in a closed tank. It comprises two clear acrylic vessels, an upper process vessel mounted above an open sump tank. The process vessel is sealed and so the air inside the tank is pressurised as water from the sump tank is pumped into it. Water drains from the process tank back into the lower sump tank via two outlets, one continuous and one incorporating a remotely controlled solenoid valve. Both outlets incorporate interchangeable orifices plus a hand operated variable valve, allowing the flow of water to be varied continuously to suit particular demonstrations. This flexible arrangement allows a wide range of control scenarios to be set up, including two fundamentally different processes, i.e. Pressure control by proportionally varying pump speed (Inflow control) Pressure control by time-proportioned opening of a solenoid valve (Outflow control) When using inflow control, repeatable disturbances can be implemented using the solenoid valve, and varied by using the different orifice sizes. When using outflow control the pump speed can be stepped to provide a full range of repeatable disturbances. These techniques allow direct comparison of different controller settings.
Specification
- A pressure control process trainer, comprising:
- 2 litre Process tank, mounted above a 3.5 litre sump tank 0-1 bar pressure range
- Two discharge ports, one with remote controlled solenoid valve and one with manually controlled valve.
- Four interchangeable orifices for use with the discharge valves
- Variable speed submersible centrifugal pump used to pressurise the air by water pressure.
- Capable of both analogue PID control using the pump and time proportioning PID control using the solenoid valve
- USB interface to PC, plus connection terminals for interfacing to external controllers
- Supplied with educational software for PID control as well as data logging.
