About the high pressure dual valve vary-p controller
|Cv: 1.0·E-5 … 8.4·E-3 | Max. Temperature: 70°C | Max. Pressure: 400 barg
Dome loaded back pressure regulators require a reference pressure to hold the upstream pressure with a ratio of 1:1 – for high-pressure applications, this can be a challenge. Pressure Control Solutions developed this dual valve electronic pressure controller that allows you to set the reference pressure in a range from 8 to 400 bar gauge.
Little to no consumption & stable pressure control
The valves used in this combination have an internal pressure compensating mechanism, enabling an extremely stable pressure control. The required pressure can be achieved without any overshoot. This helps to minimize the consumption of highly pressurized reference gas. Only when you lower the setpoint, some reference gas will be released to the atmosphere. When processing at a fixed setpoint, the consumption of reference gas is zero. Stability and control rangeability of this electronic pressure controller is unsurpassed.
Just like the ppc dual valve controller, this product is based on the PID controller used in the Bronkhorst El-Press series. To address market demand for an electronic pressure controller that can handle higher pressure ratings without consumption, Pressure Control Solutions developed this product and thus added a 400 bar controller to our portfolio: This 400 bar electronic pressure controller contains a PID controller with two valve drivers, controlling the two proportional Vary-P valves. The pressure in between the valves is monitored by an external sensor. Watch this video to see how this works in practice.
Benefits of this set-up
In this set-up, we use an external sensor. This brings several benefits:
- We can match sensors that your normally use in your application
- We can minimize dead volume
- Can use high accurate pressure sensors
- Create a closed loop control by moving the pressure from the refence side to the process side
Monitoring the reference pressure can be used to create open-loop control, but also closed-loop control.
In most research applications, open-loop makes the most sense: Since the flows are low, the pressure drop over the Equilibar regulator is neglectable. moreover, open loop control is easier to tune with ultra-low flows (<20 mln/min) than closed-loop. With higher flow rates, a closed-loop can be helpful: When monitoring the actual process pressure with a pressure sensor connected to the PID controller, the PID settings can be set such that even the slightest pressure drop over the BPR is eliminated. This allows the use of smaller sizes back pressure regulators, thus resulting in an effective yet price-efficient solution.