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Overcoming Pump Limitations

Various pumps in non-pressurised systems can be used to induce liquid movement or flow. However, the pumps can have limitations in both batch and continuous processes.

• Gravity pumps have to be located below the fluid source and are usually not automated, which limits configurability and ease of use
• Peristaltic pumps induce pulsating flow, reducing repeatability. This can be problematic in certain dosing applications such as dye and flavour dosing
• Syringe pumps are limited to small batches, and it is impractical to use them in continuous processes

These limitations can be mitigated by using a gear pump with a Coriolis mass flow meter.

How Does a Coriolis Meter-pump System Work?

The meter-pump setup works as follows:

1. The Coriolis meter sends an analog valve drive signal to the pump
2. This directs the pump to change speed
3. The bypass valve smooths out the flow below the pump’s typical minimal flow rate which then widens the operating range of the pump
4. The fluid flowing through the bypass valves isn’t measured
5. It is then recirculated back into the system upstream of the pump

Benefits of the Meter-pump System in Flow Control

The setup eliminates pump limitations that are expressed above and provides additional benefits to improve flow control in non-pressurised systems.

• Fits any set up: The meter-pump systems aren’t dependent on pressurised liquid or gravity to create flow which means it can be built to fit any space

• Smooth, precise flow at low flow rates: The meter communicates with the gear pump, smoothing out flow control at flow rates below the normal control range of the gear pump. Coriolis meters are accurate down to 0.02% of full scale
• Automated control with no need for a PLC: The meter uses  RS-232, RS-485, Modbus RTU, EtherCAT, or EtherNet/IP to communicate. The Coriolis meters also have built in PLCs, so there is no need for a complex system setup that requires a PLC
• Totalizer and alarm functionality – Meters are equipped with totalizers to record flow over time. Users can also set alarms to automatically shut off the pump

Using a CODA Coriolis meter alongside a gear pump easily automates processes and creates smooth flows across a wide operating range. These meters can adapt to work with peristaltic or syringe pumps if needed.

Common Applications

1. Food flavouring: The Coriolis meter-pump systems can provide high-precision control in batch and continuous food flavouring processes. The system has precise amounts of the liquid precursor from an unpressurised container into a vaporising process. The vapor then interacts with a carrier gas like Argon and is sent into the final coating process.
2. Pharmaceutical cleaning agents: For pharmaceutical processes, cleaning agents can be very expensive and must be flowed in at accurate amounts to meet sterilisation standards. Using a Coriolis meter-pump system can be used to flow exact amounts of cleaning agents through the system, meeting the regulatory requirements and diminishing waste.
3. Dyes and fragrances for consumer products: Creating consumer products like laundry detergent and hand soaps requires precise flow control of highly concentrated dyes and fragrances, with solution to concentrate ratios as high as 10,000:1. The meter-pump systems uses these unpressurised dyes and fragrances into the solution.