Well over a dozen technologies are used as the basis of measuring flow, but there are also so many variables that selecting the best technology can be difficult.
One way to simplify things is by summarising these variables into a ‘selection triangle’ of three key values:
- Capacity: this refers to how much flow a meter of a particular size can handle, and the extent of the resulting pressure drop.
- Accuracy: most applications demand a high degree of consistency in results, but not all require the same level of accuracy. In slimming down the choice of flowmeter, ask yourself which types of device most closely match your accuracy requirements.
- Physical dimensions: the space occupied by a flowmeter is assuming increasing importance, especially when a system is being upgraded and a new meter needs to fit into the same space as the old one that it’s replacing.
Satisfying each of the values within this ‘selection triangle’ can provide a useful path to selecting the appropriate type of flowmeter for a given task.
This three-sided approach to flowmeter selection is increasingly pointing to coriolis-type meters as a viable technology.
Coriolis meters work by measuring the mass flow rate and density of a fluid or gas as it flows through a vibrating tube. By also measuring temperature, the meters enable additional calculations about the substance’s concentration.
This combination of measurements can be highly useful in many applications. In oil extraction, the combined measurements available using a coriolis meter can help determine how much water is coming out of the ground with the oil, providing a useful indicator of overall production efficiency.
The working principles of coriolis meters offer several distinct advantages. With no moving parts, they require little maintenance or upkeep.
Once calibrated at the factory, they also tend to remain calibrated throughout their lifecycle.
Moreover, because coriolis is the only principle capable of measuring mass flow of gas and liquids without any calculation, results are independent of changes in temperature or pressure. The use of coriolis flowmeters also allows for density measurement, making them a true multi-variable metering solution for filling operations in chemical, food and other such process industries.
Furthermore, the multi-variable nature of coriolis meters enables them to deal with issues that cripple other technologies. One example is in applications with turbulent flow. Where flow is turbulent, other technologies may require a run of straight pipe to smooth the flow before it’s measured. With no need for such measures, Coriolis meters can be installed in a small footprint, with the added option of either horizontal or vertical mounting. This minimises the space required for installation and opens up financial savings through reduced expenditure on pipework alterations and overall engineering.
The use of coriolis meters can also deliver benefits where the density of the measured substance isn’t uniform.
Developments in coriolis flowmetering technology have made newer devices more compact, easier to operate, and increasingly accurate. The newest models also require up to 25 percent less pump energy to operate and create a smaller pressure drop.
One of the great advantages of a coriolis meter is the reproducibility of its measurement. It will yield consistent results almost indefinitely without requiring maintenance or calibration.
Modern meters are also becoming easier to use. ABB’s CoriolisMaster meters, for example, have an intuitive three-button interface, making most routine functions accessible without consulting a manual. Further, when maintenance is required, the meter’s electronic module can be quickly removed and replaced, with no need for recalibration or configuration.
Saving money with Coriolis metering
The inherent benefits of Coriolis flowmeters enable them to deliver real savings. One example is a chemical manufacturer that changed its process for fulfilling customer-specified concentrations of acid, which were sold by weight.
Originally, its process involved pumping a calculated amount of acid into a tanker truck, and then adding another calculated amount of water to reduce the concentration. Trucks could typically be filled in 40 minutes to a final weight and concentration that were within contracted tolerance.
Today, using a coriolis mass flowmeter, the acid and additive are mixed inline and pumped into the tanker in single process; the proper concentration is assured by the coriolis meter’s ability to measure density; the proper weight is assured by its ability to measure the flow of mass.
As a result of the change, the time needed to fill a truck was halved. With 5,000 loads fulfilled a year, the savings amounted to 1,650 hours – about 10 weeks equivalent.
The new flowmeter improved margins on existing business, and created an effective capacity increase that allowed the company to add new contracts.
The ability of Coriolis flowmeters to deliver versatile, highly accurate measurement in a compact, easy to install and use design, make them the better alternative to other flowmeter technologies in an expanding range of situations.
ABB has extensive experience in the design, manufacture, supply and lifetime care of a wide variety of metering technologies, including Coriolis mass flowmeters. For more information, or general advice on flowmeter selection, email firstname.lastname@example.org or call 0870 600 6122 ref. ‘Flow advice’.