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FLOW & LEVEL CONTROL FIVE FLOW METER CONSIDERATIONS


Titan Enterprises reports on the considerations required when choosing a flow measuring device for batching control


the general batching system. We discuss five key considerations when choosing a flow meter that will ensure your batching process runs smoothly. Probably the most recognised batch filling


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changes in upstream or downstream flow can be accurately monitored. In drinking water plants, public safety is the number one priority, and use of this technology means there is no longer the risk of under or overdosing of chlorine that could present a potential health hazard. A chlorine analyser alone is not enough to ensure public safety. Working with a drinking water plant operator whose system consists of 134 artesian wells


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that tap into the Floridan aquifer, FLEXIM carried out flow measurement on small, low flow Sodium Hypochlorite lines, as it had become apparent that the chlorine analysers currently being used by the operator’s 38 unmanned plants were not enough to ensure public safety. The chemical is used to maintain a residual of chlorine throughout the drinking water distribution system, and a pump check valve had become stuck in the open position on one of the Sodium Hypochlorite Metering Pump Skids, causing a slug of water with an exceptionally high level of chlorine to enter the distribution system. Shockingly, this caused a local resident to suffer chemical burns while showering. The operator found that the meters that they had


installed as a backup indicator of high chemical delivery only worked some of the time. During off peak times the magnetic flowmeter could not detect the flow because the velocity was too low. It was clear that a more effective solution was needed. Because all measurement is carried out externally


with clamp-on ultrasonic technology, there is no contact with the drinking water, and therefore no risk of contamination. And safety is guaranteed thanks to a range of alarm features that are designed to alert in potentially dangerous situations, indicating if a check valve should ever become stuck, if the chemical tank runs dry or a chlorine delivery line bursts for example. E: sales@flexim.co.uk www.flexim.co.uk


2 JULY/AUGUST 2022 | PROCESS & CONTROL 0


system is that of beverages, either directly into a glass or into bottles. But batching systems are also integral to the pharmaceutical and medical, and chemical and oil industries. Additive injection or chemical dosing are typical applications


itan has published a white paper on the use of ultrasonic flowmeters in high- speed batching, but here we focus on


where flow meters are used to precisely control the amount of liquid dispensed, which is critical in such processes. 1. Repeatability is essential for a


productive batching process -Multiple uncertainties can change the amount of liquid being dispensed, causing a negative effect on the repeatability of the system. Controlling as many process variables as possible will help to


KEEPING DRINKING WATER SAFE


n order to help keep drinking water safe, non-invasive clamp-on ultrasonic flowmeters are attached to the outside of the pipe, enabling the volume flow to be measured without process interruption. By using sound waves to calculate the transit time of a liquid,


ensure the accuracy and repeatability of flow measurement. Flowmeters, such as Titans’ mini turbines, can boast repeatability of 0.1% or better when operating under the same conditions. 2. The physical properties of the batch-


filled liquid will dictate equipment requirements - The choice of flowmeter may be limited by the properties of the liquid – whether it is viscous, volatile, corrosive, flammable, or contaminated with particles, for example. An oval gear flowmeter suits batch- dosing high-viscosity liquids such as syrups, whereas a turbine flow device, such as Titan’s 800-series flowmeters, is more appropriate for water and beer dispensing. 3. Maintaining constant process


conditions - Changes in flow rate, temperature and pressure may cause the flow meter to function in an unpredictable dynamic way. Although maintaining operating parameters at a stable point is optimal, this may not always be possible and fluctuating flow rates for example, can be compensated for by using a higher specification measuring device, such as Titan’s Atrato ultrasonic flowmeter. 4. Constant liquid flow or pulsations? -


Keeping the overall flow constant and avoiding any pulsations within the batching system will prevent aliasing and incorrect flow readings over the batch operating cycle. If pulsation is inherent, flowmeter choice is crucial to mitigate the effects of pulsating flow. 5. Limiting system inertia - Simple


adjustments to the batch system design, such as control value specification and the positioning of the flow meter, can help to offset the effects of inertia. Choosing the correct flow meter for a


batch system can be complex. Titan Enterprises are happy to help you find the best flow meter solution for your process and plant.


Titan Enterprises www.flowmeters.co.uk


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