Cost savings thanks to clamp-on technology
Retrofitting a Katronic flow meter saves water supply companies from costly construction work and water supply shortages.
Non-invasive flow measurement for chlorine dosing
Non-invasive ultrasonic flow measurement has already proven its worth in a wide range of applications worldwide. Fast, reliable and accurate, ultrasonic flowmeters provide measurement data from the outside thanks to ‘non-invasive’ measurement, without the need to open pipes or interrupt flow processes. This helps to avoid plant downtime, loss of production and costly installation work.
A Katronic flow meter was recently installed at a water treatment plant operated by a major British water company, which treats water drawn from two reservoirs and supplies more than 200,000 residents.
One of the main tasks in water treatment is the disinfection of the water, which is carried out at the plant by adding chlorine. The water flows through the 830 mm (DN) pipeline at an average flow rate of 640 litres per second (45–46 Ml/day). Absolutely accurate dosing of the chlorine is of paramount importance here. Originally, measurements were carried out using an electromagnetic in-line flow meter; however, this proved to be unreliable and prone to leaks. Consequently, they required a replacement measuring device that could deliver reliable, accurate and repeatable measurements and could also be installed with minimal disruption to the process.
The only access to the pipework was via an inspection hatch leading into a relatively small pit. Installing a comparatively large electromagnetic flow meter would have required extensive and costly construction work, which would have interrupted the process. This, in turn, would have meant finding an alternative water supply solution for the local population during the construction period.
A stationary flow measurement system from Katronic consists of a compact, wall-mounted unit for signal analysis and communication, as well as a robust pair of transducers that are clamped onto the pipeline. It took just a matter of minutes down in the pit to clamp the sensors onto the pipe and connect them to the remotely mounted KATflow 150 flow meter. A key advantage of Katronic’s measuring equipment is the quick and straightforward installation and set-up of the system. Within a few minutes, a reliable 4–20 mA signal was being output, proportional to the flow rate required by the chlorine dosing system.
As long as the pipe is fully filled, the system is largely independent of the liquid being measured. The time-of-flight difference method on which the measurement system is based compares the ‘travel time’ of a signal propagating in the direction of flow with the time taken by a signal sent upstream, in order to derive the flow rate from the resulting difference.
