Raising the Equilibar: Pairing an Alicat with a dome-loaded pressure regulator

Equilibar back pressure regulators (BPRs) and flow control valves (FCVs) offer stable control across an extremely wide range of flow rates, with models offering control of Cv down to 1e^-9. Equilibar valves also come in models with chemical resistance and high temperature tolerances up to 450ºC. The dome-loaded, multiple orifice design offers instantaneous control and exceptional precision for the most complex applications. Using a flexible mechanical diaphragm as its only moving part to provide frictionless and stable operation, Equilibar valves provide superior precision and repeatability, especially for low flow rates, mixed phase fluids, corrosive media, and extreme temperatures and pressures.

Equilibar valves and Alicat precision instruments are complementary when used in combination. Both have extremely high resolution, allowing each to take advantage of the other’s high precision control.

Regulating pressure with an Equilibar back pressure regulator and Alicat pressure controller

Alicat PCD-Series dual valve pressure controllers can regulate pressure for a closed volume up to 3000 PSI. The high resolution of the PCD provides phenomenal 1:1 control to the dome of an Equilibar back pressure regulator, resulting in pressure regulation to hundredths of a PSI.

In this basic configuration, Alicat’s PCD pressure controller functions as an electronic pressure controller in a control loop with the Equilibar BPR, communicating either through a PLC/PID or a computer. By automating Equilibar’s dome pressure setpoints, Alicat’s pressure controllers allow for precise and repeatable operating pressure in even the most challenging processes.

Example applications

Some popular examples in which Alicat’s pressure controllers are used in combination with Equilibar valves include:

• Operating pressures above 1000 PSI
• Fluids at extreme temperatures
• High flow rates
• Benchtop lab testing where operators want to avoid purchasing a standalone pressure controller
• Severe chemicals or mixed phase fluids
• Research and catalysis applications

Important note

When using an Alicat PCD-Series device with an Equilibar valve, make sure that the PCD is protected so as to not be exposed to moisture, heat, or vibrations, as these conditions can reduce system accuracy or damage instruments. Moreover, the PCD requires its own clean, dry, inert gas supply, and cannot be used with process gas.

Regulating flow with an Equilibar flow control valve and Alicat mass flow controller

Alicat devices can also be used in combination with an Equilibar flow control valve (FCV) for mass flow control. An Alicat mass flow meter, either an M-Series for gas flow or a CODA K-Series for liquid flow, is used in a control loop with an electronic pilot pressure controller and a PLC or computer. The PLC or computer functions as a proportional-integral derivative (PID) to monitor input from the flow transmitter/flow meter to adjust the pilot pressure to the FCV and thus to control the mass flow. Using the flow meter/flow transmitter data, the electronic pressure controller translates the electronic signal from the PLC or computer into a pilot pressure signal for the Equilibar FCV dome, resulting in the desired mass flow rate.

Alternatively, the above setup is also possible without a PID controller by sending analog signals from the mass flow meter directly to the Alicat PCD pressure controller to adjust the Equilibar FCV dome.

Example applications

This is especially useful in flow applications with the following:

• Multi-phase fluids
• Mixed fluids
• Bubbles
• Foam
• Wide flow ranges
• Downstream pressure fluctuations
• Corrosive fluids
• High temperatures
• Extremely low flow rates
• Sanitary processes

Additional information and support

Equilibar valves have options for chemical compatibility with customizable models of exotic metal alloys and polymers including Hastelloy, titanium, zirconium, PTFE, and PVDF. O-ring materials can also be chosen for compatibility with highly corrosive gases and liquids. Moreover, Equilibar valves have a simple design, and they are easy to disassemble, repair, and to reassemble.

Whether your process requires precision, repeatability, accuracy, or customization, Alicat’s pressure and mass flow controllers provide the latest tech, most unique features, and fastest results for Equilibar related applications and more.