Ultrasonic flowmeters are on the rise in greenhouse horticulture. There are strong reasons for that.
To keep control over water consumption and flow capacities, the need for fast and accurate measuring is growing. In the past, mainly mechanical instruments were used for this purpose, such as a propeller or a paddle wheel. However, since they made their entry into greenhouse horticulture, ultrasonic flowmeters have been steadily gaining ground. The advantages of these instruments over mechanical ones justify the higher purchase costs.
MECHANICAL VS. ULTRASONIC
Mechanical meters work based on moving parts in the water flow. These are exposed to wear and contamination, making regular maintenance a must. Despite this, the accuracy deteriorates over time. Ultrasonic meters have no moving parts, but work on the basis of sound vibrations. Meaning less wear, less pollution and less maintenance.
Because of those moving parts, mechanical gauges provide the most accurate results at a stable flow with as little turbulence as possible. In the ideal situation, the meter is located in the middle of a relatively long stretch of straight pipe. This can be problematic for the installation of such meters in existing systems. Ultrasonic meters are much more compact and therefore easier to build in.
INVASIVE VS. NON-INVASIVE
Mechanical gauges are invasive. With existing systems, this means that the flow process must be interrupted in order to open up the pipe and install the meter. Associated risks include obstruction and additional contamination within the piping, and also leakage loss. Ultrasonic meters are available in non-invasive variants. The external mounting of the sensors enables measuring from the outside of the pipe. Benefits: no process interruptions, flexibility regarding the water system design process, no risk of contamination, no leakage and no recalibration required.
VERSATILE
Another argument for opting for ultrasonic meters is the fact that they can measure bi-directionally as standard, while a propeller or paddle wheel only registers the forward or return flow. In extensive water systems this can result in a saving of one or more meters.
The technical versatility of ultrasonic meters makes them programmable for various types of output. In addition, they are equipped with a Modbus module to connect several meters, enabling the availability of more information in real time.
TREND
The increase in popularity of ultrasonic measuring equipment is in line with the trend of scaling up, increasing tap sections and making water consumption in greenhouse horticulture more sustainable. Cultivation in a closed greenhouse with reuse of tap water and the mandatory purification of residual water necessitates accurate registration of internal water flows. From that point of view, even small improvements can lead to significant savings.
