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:
- The Coriolis meter sends an analog valve drive signal to the pump
- This directs the pump to change speed
- The bypass valve smooths out the flow below the pump’s typical minimal flow rate which then widens the operating range of the pump
- The fluid flowing through the bypass valves isn’t measured
- 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.
- 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.
- 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.
- 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.